/* ----------------------------------------------------
   LINUX SOC HANDBOOK - ULTIMATE PLATFORM STYLESHEET
   ---------------------------------------------------- */

:root {
  /* Ruled Notebook Light Palette */
  --bg-app: #f4edd9;
  --paper-bg: #fffdf5;
  --paper-line: #d8e3ef;
  --margin-line: #f28b82;
  --text-ink: #1a237e;
  --text-dark: #212121;
  --accent-blue: #1565c0;
  --accent-red: #d32f2f;
  --accent-green: #2e7d32;
  --sticky-bg: #fff59d;
  --sticky-text: #212121;
  --sticky-shadow: rgba(0, 0, 0, 0.12);
  --terminal-bg: #1e1e1e;
  --terminal-text: #4af626;
  --card-border: #e0d7c3;
  --font-hand: 'Kalam', 'Architects Daughter', cursive;
  --font-mono: 'Fira Code', monospace;
  --font-sans: 'Outfit', sans-serif;
  --intent-bg: rgba(255, 152, 0, 0.1);
  --intent-border: #f57c00;
  --intent-text: #333;
  --ideal-bg: rgba(46, 125, 50, 0.1);
  --ideal-border: #2e7d32;
  --ideal-text: #1b5e20;
  --protip-bg: #e8eaf6;
  --protip-border: #1565c0;
  --protip-text: #1565c0;
  --sticky-top-offset: 115px;
  --sidebar-height: calc(100dvh - 115px);
  --mobile-bottom-nav-space: 72px;
}

/* Dark Cyber Theme (High-Contrast Fixes) */
body.theme-cyber {
  --bg-app: #090d16;
  --paper-bg: #111827;
  --paper-line: rgba(56, 189, 248, 0.12);
  --margin-line: #00f2fe;
  --text-ink: #f8fafc;
  --text-dark: #cbd5e1;
  --accent-blue: #38bdf8;
  --accent-red: #ff5252;
  --accent-green: #4ade80;
  --sticky-bg: #1c1902;
  --sticky-text: #ffee55;
  --sticky-shadow: rgba(255, 238, 85, 0.2);
  --terminal-bg: #05080e;
  --terminal-text: #4af626;
  --card-border: #1e293b;
  --intent-bg: rgba(255, 152, 0, 0.18);
  --intent-border: #ff9800;
  --intent-text: #ffe0b2;
  --ideal-bg: rgba(74, 222, 128, 0.15);
  --ideal-border: #4ade80;
  --ideal-text: #f0fdf4;
  --protip-bg: #0f172a;
  --protip-border: #38bdf8;
  --protip-text: #38bdf8;
}


* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: var(--font-sans);
  background-color: var(--bg-app);
  color: var(--text-dark);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  overflow-x: hidden;
}

body.splash-active,
body.drawer-open {
  overflow: hidden;
}

/* --- APP BRAND HEADER --- */
.app-header {
  background: var(--paper-bg);
  border-bottom: 2px solid var(--card-border);
  padding: 0.6rem 1.5rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: 0 4px 12px rgba(0,0,0,0.05);
}

.header-left {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.brand-header-logo {
  width: 52px;
  height: 52px;
  border-radius: 50%;
  border: 2px solid var(--accent-blue);
  box-shadow: 0 2px 8px rgba(0,0,0,0.2);
}

.header-left h1 {
  font-size: 1.25rem;
  font-weight: 800;
  color: var(--text-ink);
}

.brand-tagline {
  color: var(--accent-blue);
  font-size: 0.95rem;
  font-weight: 700;
}

.header-subtitle {
  font-size: 0.8rem;
  color: var(--text-dark);
  margin-top: 0.1rem;
}

/* --- HEADER PROFILE SOCIAL LINKS --- */
.header-profiles {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  margin: 0 auto;
}

.mode-tab {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
}

.mode-tab svg {
  flex-shrink: 0;
  vertical-align: middle;
  transition: transform 0.2s ease;
}

.mode-tab:hover svg {
  transform: scale(1.18);
}

.cyber-chip {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
}

.cyber-chip svg {
  flex-shrink: 0;
  vertical-align: middle;
}

.profile-pill {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.4rem 0.8rem;
  border-radius: 50px;
  font-size: 0.82rem;
  font-weight: 600;
  text-decoration: none;
  transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
  box-shadow: 0 2px 6px rgba(0, 0, 0, 0.08);
  border: 1px solid rgba(0, 0, 0, 0.1);
  white-space: nowrap;
  cursor: pointer;
}

.profile-pill .profile-icon {
  flex-shrink: 0;
  transition: transform 0.2s ease;
}

.profile-pill:hover {
  transform: translateY(-2px) scale(1.03);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.18);
}

.profile-pill:hover .profile-icon {
  transform: scale(1.15);
}

/* GitHub Badge */
.btn-github {
  background: #24292e;
  color: #ffffff;
  border-color: #1b1f23;
}
.btn-github:hover {
  background: #000000;
  color: #58a6ff;
  border-color: #58a6ff;
}

/* LinkedIn Badge */
.btn-linkedin {
  background: #0a66c2;
  color: #ffffff;
  border-color: #004182;
}
.btn-linkedin:hover {
  background: #004182;
  color: #70b5f9;
  border-color: #70b5f9;
}

/* Email Badge */
.btn-email {
  background: linear-gradient(135deg, #ea4335, #d93025);
  color: #ffffff;
  border-color: #b31412;
}
.btn-email:hover {
  background: linear-gradient(135deg, #d93025, #b31412);
  color: #ffffff;
  border-color: #ff8a80;
}

/* Dark Cyber Theme Adjustments */
body.theme-cyber .profile-pill {
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.4);
}
body.theme-cyber .btn-github {
  background: #161b22;
  color: #f0f6fc;
  border-color: #30363d;
}
body.theme-cyber .btn-github:hover {
  background: #21262d;
  color: #58a6ff;
  border-color: #58a6ff;
  box-shadow: 0 0 12px rgba(88, 166, 255, 0.4);
}

body.theme-cyber .btn-linkedin {
  background: #0a66c2;
  color: #ffffff;
  border-color: #38bdf8;
}
body.theme-cyber .btn-linkedin:hover {
  background: #004182;
  color: #e0f2fe;
  border-color: #38bdf8;
  box-shadow: 0 0 12px rgba(56, 189, 248, 0.4);
}

body.theme-cyber .btn-email {
  background: linear-gradient(135deg, #dc2626, #b91c1c);
  color: #ffffff;
  border-color: #ef4444;
}
body.theme-cyber .btn-email:hover {
  background: linear-gradient(135deg, #ef4444, #dc2626);
  color: #ffffff;
  box-shadow: 0 0 12px rgba(239, 68, 68, 0.4);
}

.header-right {
  display: flex;
  gap: 0.6rem;
}

.btn-action {
  background: var(--paper-bg);
  border: 2px solid var(--card-border);
  color: var(--text-ink);
  padding: 0.45rem 0.85rem;
  border-radius: 8px;
  font-weight: 600;
  font-size: 0.85rem;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  transition: all 0.2s ease;
}

.btn-action:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 8px rgba(0,0,0,0.15);
}

.btn-cyber { background: #1e1e1e; color: #4af626; border-color: #333; }
.btn-pdf { background: var(--accent-red); color: #fff; border-color: var(--accent-red); }
.btn-pwa { background: linear-gradient(135deg, #7c3aed, #4f46e5); color: #ffffff; border-color: #6d28d9; }
.btn-pwa:hover { background: linear-gradient(135deg, #6d28d9, #4338ca); box-shadow: 0 0 12px rgba(124, 58, 237, 0.4); }
.btn-voice { background: linear-gradient(135deg, #0284c7, #0d9488); color: #ffffff; border-color: #0369a1; }
.btn-voice:hover { background: linear-gradient(135deg, #0369a1, #0f766e); box-shadow: 0 0 12px rgba(2, 132, 199, 0.4); }
.btn-voice.speaking { animation: pulseVoice 1.2s infinite alternate; background: #ea580c; border-color: #c2410c; }

@keyframes pulseVoice {
  from { box-shadow: 0 0 4px #ea580c; }
  to { box-shadow: 0 0 16px #f97316; transform: scale(1.04); }
}

/* --- MITRE ATT&CK MATRIX STYLES --- */
.mitre-matrix-wrapper {
  padding: 1.5rem;
  background: var(--paper-bg);
  border-radius: 14px;
  border: 2px solid var(--card-border);
  box-shadow: 0 8px 30px rgba(0,0,0,0.06);
}

.mitre-matrix-header {
  text-align: center;
  margin-bottom: 2rem;
}

.mitre-matrix-header h2 {
  font-size: 1.6rem;
  color: var(--accent-blue);
  font-family: var(--font-sans);
  margin-bottom: 0.5rem;
}

.mitre-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 1.2rem;
}

.mitre-column {
  background: var(--bg-app);
  border-radius: 12px;
  border: 1px solid var(--card-border);
  padding: 1rem;
}

.mitre-tactic-title {
  font-weight: 800;
  font-size: 0.95rem;
  color: var(--text-ink);
  padding-bottom: 0.6rem;
  margin-bottom: 0.8rem;
  border-bottom: 2px solid var(--accent-blue);
  display: flex;
  align-items: center;
  gap: 0.4rem;
}

.mitre-tech-card {
  background: var(--paper-bg);
  border: 1px solid var(--card-border);
  border-radius: 8px;
  padding: 0.8rem;
  margin-bottom: 0.7rem;
  cursor: pointer;
  transition: all 0.2s ease;
}

.mitre-tech-card:hover {
  transform: translateY(-2px);
  border-color: var(--accent-blue);
  box-shadow: 0 4px 12px rgba(21, 101, 192, 0.2);
}

.mitre-tech-id {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  font-weight: 700;
  color: var(--accent-blue);
  background: rgba(21, 101, 192, 0.1);
  padding: 0.1rem 0.4rem;
  border-radius: 4px;
  display: inline-block;
  margin-bottom: 0.3rem;
}

.mitre-tech-name {
  font-weight: 700;
  font-size: 0.88rem;
  color: var(--text-dark);
  margin-bottom: 0.3rem;
}

.mitre-tech-desc {
  font-size: 0.76rem;
  color: #64748b;
  line-height: 1.35;
}

/* --- LOG PARSER LAB STYLES --- */
.logparser-wrapper {
  background: var(--paper-bg);
  border-radius: 14px;
  border: 2px solid var(--card-border);
  padding: 1.5rem;
  box-shadow: 0 8px 30px rgba(0,0,0,0.06);
}

.log-preset-bar {
  display: flex;
  gap: 0.6rem;
  margin-bottom: 1rem;
  flex-wrap: wrap;
}

.btn-preset {
  background: var(--bg-app);
  border: 1px solid var(--card-border);
  padding: 0.4rem 0.8rem;
  border-radius: 8px;
  font-size: 0.82rem;
  font-weight: 700;
  color: var(--text-dark);
  cursor: pointer;
  transition: all 0.2s ease;
}

.btn-preset:hover {
  background: var(--accent-blue);
  color: #fff;
}

.log-textarea {
  width: 100%;
  height: 140px;
  background: #090d16;
  color: #38bdf8;
  font-family: var(--font-mono);
  font-size: 0.82rem;
  padding: 0.8rem;
  border-radius: 8px;
  border: 1px solid #1e293b;
  resize: vertical;
  margin-bottom: 1rem;
}

.log-output-box {
  background: #05080e;
  border: 1px solid #1e293b;
  border-radius: 8px;
  padding: 1rem;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  max-height: 350px;
  overflow-y: auto;
  margin-top: 1rem;
}

.log-line {
  padding: 0.2rem 0;
  line-height: 1.4;
}

.log-line.threat-high {
  background: rgba(239, 68, 68, 0.2);
  color: #fca5a5;
  font-weight: bold;
}

.log-line.threat-medium {
  background: rgba(234, 179, 8, 0.2);
  color: #fef08a;
}

/* --- HARDENING CHECKLIST STYLES --- */
.hardening-wrapper {
  background: var(--paper-bg);
  border-radius: 14px;
  border: 2px solid var(--card-border);
  padding: 1.5rem;
  box-shadow: 0 8px 30px rgba(0,0,0,0.06);
}

.score-card {
  background: linear-gradient(135deg, #1565c0, #0284c7);
  color: #fff;
  border-radius: 12px;
  padding: 1.2rem;
  text-align: center;
  margin-bottom: 1.5rem;
}

.score-bar-bg {
  background: rgba(255,255,255,0.2);
  height: 12px;
  border-radius: 999px;
  overflow: hidden;
  margin-top: 0.8rem;
}

.score-bar-fill {
  background: #4ade80;
  height: 100%;
  width: 0%;
  transition: width 0.4s ease;
}

.checklist-group {
  margin-bottom: 1.5rem;
}

.checklist-item {
  display: flex;
  align-items: flex-start;
  gap: 0.8rem;
  background: var(--bg-app);
  border: 1px solid var(--card-border);
  border-radius: 8px;
  padding: 0.8rem 1rem;
  margin-bottom: 0.6rem;
  cursor: pointer;
  transition: all 0.2s ease;
}

.checklist-item:hover {
  border-color: var(--accent-blue);
}

.checklist-item input[type="checkbox"] {
  width: 18px;
  height: 18px;
  accent-color: var(--accent-blue);
  cursor: pointer;
  margin-top: 0.1rem;
}

/* --- CHEAT SHEET STYLES --- */
.cheatsheet-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 1rem;
}

.cmd-card {
  background: var(--paper-bg);
  border: 1px solid var(--card-border);
  border-radius: 10px;
  padding: 1rem;
  position: relative;
  transition: all 0.2s ease;
}

.cmd-card:hover {
  transform: translateY(-2px);
  border-color: var(--accent-blue);
}

.btn-copy-cmd {
  position: absolute;
  top: 0.8rem;
  right: 0.8rem;
  background: var(--bg-app);
  border: 1px solid var(--card-border);
  padding: 0.2rem 0.5rem;
  border-radius: 6px;
  font-size: 0.72rem;
  cursor: pointer;
  font-weight: 700;
}

/* --- INCIDENT LABS STYLES --- */
.lab-card {
  background: var(--paper-bg);
  border: 2px solid var(--card-border);
  border-radius: 12px;
  padding: 1.4rem;
  margin-bottom: 1.5rem;
}

.quiz-option-btn {
  width: 100%;
  text-align: left;
  background: var(--bg-app);
  border: 1px solid var(--card-border);
  padding: 0.7rem 1rem;
  border-radius: 8px;
  margin-bottom: 0.5rem;
  font-weight: 600;
  font-size: 0.88rem;
  cursor: pointer;
  transition: all 0.2s ease;
}

.quiz-option-btn:hover {
  background: rgba(21, 101, 192, 0.08);
  border-color: var(--accent-blue);
}

.quiz-option-btn.correct {
  background: rgba(74, 222, 128, 0.2);
  border-color: #4ade80;
  color: #166534;
}

.quiz-option-btn.wrong {
  background: rgba(248, 113, 113, 0.2);
  border-color: #f87171;
  color: #991b1b;
}

/* --- CYBER TOOL LOGOS BAR --- */
.cyber-tools-bar {
  background: var(--paper-bg);
  border-bottom: 1px solid var(--card-border);
  padding: 0.3rem 1rem;
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 1.2rem;
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--text-dark);
  overflow-x: auto;
}

.cyber-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  background: var(--bg-app);
  padding: 0.15rem 0.6rem;
  border-radius: 12px;
  border: 1px solid var(--card-border);
  white-space: nowrap;
}

/* --- MODE TABS BAR (BALANCED SEGMENTED CONTROL & CYBER BADGES) --- */
.mode-tabs-bar {
  background: var(--paper-bg);
  border-bottom: 2px solid var(--card-border);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.5rem;
  padding: 0.5rem 1.5rem;
  width: 100%;
}

.mode-tabs-badges-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  width: 100%;
}

.header-badge-group {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  flex-shrink: 0;
}

.cyber-chip {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.35rem 0.75rem;
  border-radius: 20px;
  font-size: 0.78rem;
  font-weight: 700;
  border: 1px solid var(--card-border);
  background: var(--paper-bg);
  color: var(--text-dark);
  box-shadow: 0 1px 4px rgba(0,0,0,0.06);
  transition: all 0.2s ease;
  white-space: nowrap;
  cursor: default;
}

.cyber-chip:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 10px rgba(0,0,0,0.12);
}

.chip-linux {
  border-color: #eab308;
  color: #854d0e;
  background: rgba(254, 240, 138, 0.4);
}
.chip-blue {
  border-color: #3b82f6;
  color: #1e40af;
  background: rgba(219, 234, 254, 0.4);
}
.chip-siem {
  border-color: #10b981;
  color: #065f46;
  background: rgba(209, 250, 229, 0.4);
}
.chip-threat {
  border-color: #ef4444;
  color: #991b1b;
  background: rgba(254, 226, 226, 0.4);
}
.chip-mitre {
  border-color: #8b5cf6;
  color: #5b21b6;
  background: rgba(237, 233, 254, 0.4);
}
.chip-forensics {
  border-color: #06b6d4;
  color: #155e75;
  background: rgba(207, 250, 254, 0.4);
}

.mode-tabs-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: var(--bg-app);
  padding: 0.3rem;
  border-radius: 12px;
  border: 1.5px solid var(--card-border);
  width: 100%;
  gap: 0.3rem;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  box-shadow: inset 0 1px 3px rgba(0,0,0,0.06);
}

.mode-tab {
  flex: 1;
  background: transparent;
  border: 1px solid transparent;
  padding: 0.45rem 0.6rem;
  border-radius: 8px;
  font-weight: 700;
  font-size: 0.83rem;
  color: var(--text-dark);
  cursor: pointer;
  transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  white-space: nowrap;
}

.mode-tab:hover:not(.active) {
  background: rgba(21, 101, 192, 0.08);
  color: var(--accent-blue);
}

.mode-tab.active {
  background: var(--accent-blue);
  color: #ffffff;
  border-color: var(--accent-blue);
  box-shadow: 0 4px 12px rgba(21, 101, 192, 0.3);
}

/* Cyber Dark Mode Segmented Tabs */
body.theme-cyber .mode-tabs-container {
  background: #0b1324;
  border-color: #1e293b;
}

body.theme-cyber .mode-tab {
  color: #94a3b8;
}

body.theme-cyber .mode-tab:hover:not(.active) {
  background: rgba(56, 189, 248, 0.12);
  color: #38bdf8;
}

body.theme-cyber .mode-tab.active {
  background: linear-gradient(135deg, #1565c0, #0284c7);
  color: #ffffff;
  border-color: #38bdf8;
  box-shadow: 0 0 14px rgba(56, 189, 248, 0.4);
}

/* Cyber Dark Theme Badge Chips */
body.theme-cyber .chip-linux {
  border-color: #facc15;
  color: #fef08a;
  background: rgba(234, 179, 8, 0.15);
  box-shadow: 0 0 8px rgba(250, 204, 21, 0.2);
}
body.theme-cyber .chip-blue {
  border-color: #38bdf8;
  color: #e0f2fe;
  background: rgba(56, 189, 248, 0.15);
  box-shadow: 0 0 8px rgba(56, 189, 248, 0.2);
}
body.theme-cyber .chip-siem {
  border-color: #4ade80;
  color: #f0fdf4;
  background: rgba(74, 222, 128, 0.15);
  box-shadow: 0 0 8px rgba(74, 222, 128, 0.2);
}
body.theme-cyber .chip-threat {
  border-color: #f87171;
  color: #fef2f2;
  background: rgba(248, 113, 113, 0.15);
  box-shadow: 0 0 8px rgba(248, 113, 113, 0.2);
}
body.theme-cyber .chip-mitre {
  border-color: #c084fc;
  color: #faf5ff;
  background: rgba(192, 132, 252, 0.15);
  box-shadow: 0 0 8px rgba(192, 132, 252, 0.2);
}
body.theme-cyber .chip-forensics {
  border-color: #22d3ee;
  color: #ecfeff;
  background: rgba(34, 211, 238, 0.15);
  box-shadow: 0 0 8px rgba(34, 211, 238, 0.2);
}


/* --- COLLAPSIBLE SIDEBAR --- */
.main-container.sidebar-collapsed .sidebar {
  display: none !important;
}

.main-container.sidebar-collapsed .notebook-workspace {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
}

/* --- AUTO PLAY BUTTON --- */
.btn-play {
  background: #22c55e !important;
  color: #ffffff !important;
  border-color: #22c55e !important;
  font-weight: 700;
  box-shadow: 0 4px 10px rgba(34, 197, 94, 0.3);
}

.btn-play:hover {
  background: #16a34a !important;
}

.btn-play.playing {
  background: #ef4444 !important;
  border-color: #ef4444 !important;
  box-shadow: 0 4px 10px rgba(239, 68, 68, 0.3);
}

/* --- REALISTIC BOOK PAGE FLIP ANIMATIONS --- */
.page-flip-next {
  animation: pageFlipNext 0.45s cubic-bezier(0.25, 1, 0.5, 1) forwards;
  transform-origin: left center;
}

.page-flip-prev {
  animation: pageFlipPrev 0.45s cubic-bezier(0.25, 1, 0.5, 1) forwards;
  transform-origin: right center;
}

@keyframes pageFlipNext {
  0% {
    opacity: 0.4;
    transform: perspective(1200px) rotateY(-20deg) scale(0.97);
  }
  100% {
    opacity: 1;
    transform: perspective(1200px) rotateY(0deg) scale(1);
  }
}

@keyframes pageFlipPrev {
  0% {
    opacity: 0.4;
    transform: perspective(1200px) rotateY(20deg) scale(0.97);
  }
  100% {
    opacity: 1;
    transform: perspective(1200px) rotateY(0deg) scale(1);
  }
}

/* --- MAIN CONTAINER & SIDEBAR --- */
.main-container {
  display: flex;
  flex: 1;
  transition: all 0.35s ease;
}

/* Reading Mode: Full-width centered when sidebar hidden */
.main-container.sidebar-collapsed .notebook-workspace {
  width: 100%;
  display: flex;
  flex-direction: column;
  align-items: center;
}

.main-container.sidebar-collapsed .notebook-controls {
  max-width: 860px;
  width: 100%;
}

.main-container.sidebar-collapsed .notebook-page-container {
  max-width: 860px;
  width: 100%;
  box-shadow: 0 8px 48px rgba(0,0,0,0.22);
  border-radius: 12px;
}


.sidebar {
  width: 330px;
  background: var(--paper-bg);
  border-right: 2px solid var(--card-border);
  display: flex;
  flex-direction: column;
  height: var(--sidebar-height);
  position: sticky;
  top: var(--sticky-top-offset);
}


.sidebar-search {
  padding: 0.8rem;
  border-bottom: 1px solid var(--card-border);
}

.sidebar-search input {
  width: 100%;
  padding: 0.55rem 0.8rem;
  border: 2px solid var(--card-border);
  border-radius: 8px;
  font-size: 0.85rem;
  background: var(--bg-app);
  color: var(--text-ink);
  outline: none;
}

.sidebar-filters {
  display: flex;
  gap: 0.5rem;
  padding: 0.4rem 0.8rem;
  border-bottom: 1px solid var(--card-border);
}

.filter-btn {
  flex: 1;
  padding: 0.35rem;
  border: 1px solid var(--card-border);
  background: var(--bg-app);
  border-radius: 6px;
  font-size: 0.8rem;
  font-weight: 600;
  cursor: pointer;
  color: var(--text-ink);
}

.filter-btn.active {
  background: var(--accent-blue);
  color: #ffffff;
  border-color: var(--accent-blue);
}

.module-nav {
  flex: 1;
  overflow-y: auto;
  padding: 0.5rem;
}

.module-group { margin-bottom: 0.8rem; }

.module-title {
  font-family: var(--font-hand);
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--accent-red);
  padding: 0.3rem 0.5rem;
  border-bottom: 2px dashed var(--card-border);
  margin-bottom: 0.3rem;
}

.page-item {
  padding: 0.45rem 0.7rem;
  border-radius: 6px;
  font-size: 0.85rem;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 0.2rem;
  color: var(--text-ink);
  transition: background 0.15s;
}

.page-item:hover { background: var(--bg-app); }
.page-item.active { background: var(--accent-blue); color: #ffffff; font-weight: 600; }
.page-item .page-num { font-size: 0.75rem; background: rgba(255,255,255,0.15); padding: 0.1rem 0.4rem; border-radius: 4px; }

/* --- NOTEBOOK WORKSPACE --- */
.notebook-workspace {
  flex: 1;
  padding: 1.5rem 2rem;
  overflow-y: auto;
}

.notebook-controls {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 1.2rem;
  background: var(--paper-bg);
  padding: 0.6rem 1rem;
  border-radius: 10px;
  border: 2px solid var(--card-border);
  gap: 0.8rem;
  flex-wrap: wrap;
}

/* Toolbar group layout */
.toolbar-left-group {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.quick-tags {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}


.page-switcher { display: flex; align-items: center; gap: 0.8rem; color: var(--text-ink); }

.nav-arrow {
  background: var(--accent-blue);
  color: #ffffff;
  border: none;
  padding: 0.4rem 0.8rem;
  border-radius: 6px;
  font-weight: 600;
  cursor: pointer;
}

.page-indicator input {
  width: 55px;
  text-align: center;
  padding: 0.2rem;
  border: 1px solid var(--card-border);
  border-radius: 4px;
  font-weight: 700;
  background: var(--bg-app);
  color: var(--text-ink);
}

.btn-star {
  background: var(--bg-app);
  border: 2px solid #ffe082;
  color: #f57f17;
  padding: 0.4rem 0.8rem;
  border-radius: 6px;
  font-weight: 600;
  cursor: pointer;
}

.btn-star.bookmarked { background: #f57f17; color: #ffffff; }

/* --- HANDWRITTEN RULED PAPER PAGE STYLING --- */
.notebook-page-container { max-width: 940px; margin: 0 auto; }

.ruled-paper {
  background-color: var(--paper-bg);
  background-image: repeating-linear-gradient(
    var(--paper-bg) 0px,
    var(--paper-bg) 31px,
    var(--paper-line) 32px
  );
  line-height: 32px;
  padding: 2.5rem 3rem 2.5rem 4rem;
  border-radius: 6px;
  border: 1px solid var(--card-border);
  box-shadow: 0 10px 30px rgba(0,0,0,0.15);
  position: relative;
  margin-bottom: 2rem;
  overflow: hidden;
}

/* Red Vertical Margin Line */
.ruled-paper::before {
  content: '';
  position: absolute;
  top: 0;
  bottom: 0;
  left: 3.2rem;
  width: 2px;
  background-color: var(--margin-line);
  z-index: 1;
}

/* Brand Watermark Overlay on Pages */
.brand-watermark-stamp {
  position: absolute;
  top: 1.5rem;
  right: 1.5rem;
  width: 90px;
  opacity: 0.85;
  pointer-events: none;
  transform: rotate(-6deg);
}

.page-header-row {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  margin-bottom: 1.5rem;
  border-bottom: 2px solid var(--text-ink);
  padding-bottom: 0.5rem;
  padding-right: 6rem;
}

.concept-title-box h2 {
  font-family: var(--font-sans);
  font-size: 1.5rem;
  color: var(--text-ink);
  font-weight: 800;
  text-transform: uppercase;
}

.concept-tag {
  display: inline-block;
  background: var(--accent-red);
  color: #ffffff;
  font-size: 0.75rem;
  font-weight: 700;
  padding: 0.15rem 0.5rem;
  border-radius: 4px;
  margin-top: 0.3rem;
}

.page-stamp {
  font-family: var(--font-hand);
  font-weight: 700;
  font-size: 1.1rem;
  color: var(--accent-blue);
  border: 2px solid var(--accent-blue);
  padding: 0.2rem 0.6rem;
  border-radius: 8px;
  transform: rotate(-3deg);
}

.section-block { margin-bottom: 1.5rem; }

.section-label {
  font-family: var(--font-sans);
  font-weight: 800;
  font-size: 0.85rem;
  text-transform: uppercase;
  color: var(--accent-red);
  letter-spacing: 1px;
  margin-bottom: 0.3rem;
}

.handwritten-text {
  font-family: var(--font-hand);
  font-size: 1.25rem;
  color: var(--text-ink);
  line-height: 32px;
}

.cmd-box {
  background: var(--terminal-bg);
  color: var(--terminal-text);
  font-family: var(--font-mono);
  padding: 0.8rem 1.2rem;
  border-radius: 8px;
  font-size: 0.95rem;
  margin: 0.5rem 0;
  box-shadow: 2px 4px 10px rgba(0,0,0,0.3);
  position: relative;
  white-space: pre-wrap;
  word-break: break-all;
  border: 1px solid var(--card-border);
}

.syntax-box {
  background: rgba(56, 189, 248, 0.12);
  border-left: 4px solid var(--accent-blue);
  padding: 0.6rem 1rem;
  font-family: var(--font-mono);
  font-size: 0.9rem;
  color: var(--text-ink);
  border-radius: 0 6px 6px 0;
}

.sticky-note {
  background: var(--sticky-bg);
  color: var(--sticky-text);
  font-family: var(--font-hand);
  font-size: 1.2rem;
  padding: 1rem 1.5rem;
  border-radius: 4px;
  box-shadow: 3px 6px 12px var(--sticky-shadow);
  transform: rotate(-1.5deg);
  margin: 1.5rem 0 1rem 0;
  position: relative;
  border-left: 6px solid #fbc02d;
}

.diagram-box {
  border: 2px dashed var(--accent-blue);
  background: rgba(0, 0, 0, 0.2);
  padding: 1rem;
  border-radius: 8px;
  font-family: var(--font-mono);
  font-size: 0.88rem;
  color: var(--text-ink);
  white-space: pre-wrap;
  margin: 1rem 0;
}


/* --- INTERVIEW CARD STYLING --- */
.interview-card {
  background: var(--paper-bg);
  border: 2px solid var(--card-border);
  border-radius: 12px;
  padding: 2rem;
  box-shadow: 0 8px 24px rgba(0,0,0,0.15);
  margin-bottom: 2rem;
  position: relative;
}

.qa-intent-box {
  background: var(--intent-bg);
  border-left: 4px solid var(--intent-border);
  color: var(--intent-text);
  padding: 0.8rem 1.2rem;
  border-radius: 0 8px 8px 0;
  font-size: 0.9rem;
  margin: 1rem 0;
}

.qa-ideal-box {
  background: var(--ideal-bg);
  border-left: 4px solid var(--ideal-border);
  color: var(--ideal-text);
  padding: 1rem 1.2rem;
  border-radius: 0 8px 8px 0;
  font-size: 0.95rem;
  font-weight: 500;
  margin: 1rem 0;
}

.pro-tip-box {
  background: var(--protip-bg);
  border: 2px dashed var(--protip-border);
  color: var(--protip-text);
  padding: 0.8rem 1.2rem;
  border-radius: 8px;
  font-family: var(--font-sans);
  font-size: 0.9rem;
  font-weight: 600;
  margin-top: 1.5rem;
}

/* --- OFFICIAL COVER PAGE STYLING --- */
.brand-cover-page {
  background: var(--paper-bg);
  border: 4px double var(--accent-blue);
  border-radius: 16px;
  padding: 3rem;
  text-align: center;
  box-shadow: 0 15px 40px rgba(0,0,0,0.2);
  margin-bottom: 2rem;
}

.cover-logo-hero {
  width: 180px;
  height: 180px;
  border-radius: 50%;
  border: 4px solid var(--accent-blue);
  box-shadow: 0 8px 25px rgba(56, 189, 248, 0.4);
  margin-bottom: 1.5rem;
}

.cover-title {
  font-size: 2.2rem;
  font-weight: 900;
  color: var(--text-ink);
  text-transform: uppercase;
  letter-spacing: 1px;
}

.cover-subtitle {
  font-size: 1.2rem;
  color: var(--accent-red);
  font-weight: 700;
  margin-top: 0.5rem;
}

.cover-badge-row {
  display: flex;
  justify-content: center;
  gap: 1rem;
  margin: 2rem 0;
  flex-wrap: wrap;
}

.cover-badge {
  background: var(--accent-blue);
  color: #ffffff;
  padding: 0.6rem 1.2rem;
  border-radius: 30px;
  font-weight: 700;
  font-size: 0.9rem;
}

/* --- SVG DIAGRAM RESPONSIVENESS --- */
.svg-diagram {
  width: 100%;
  height: auto;
  margin: 1rem 0;
  border-radius: 8px;
}

/* --- INTERACTIVE TERMINAL MODAL --- */
.terminal-modal {
  position: fixed; top: 0; left: 0; right: 0; bottom: 0;
  background: rgba(0,0,0,0.75); z-index: 1000;
  display: flex; justify-content: center; align-items: center;
  backdrop-filter: blur(4px);
}
.terminal-modal.hidden { display: none; }
.terminal-window {
  width: 800px; max-width: 90%; height: 500px;
  background: #090d16; border-radius: 10px; border: 1px solid #333;
  display: flex; flex-direction: column; box-shadow: 0 20px 50px rgba(0,0,0,0.5); overflow: hidden;
}
.terminal-header {
  background: #1e293b; padding: 0.6rem 1rem;
  display: flex; justify-content: space-between; align-items: center; border-bottom: 1px solid #333;
}
.term-dots { display: flex; gap: 0.4rem; }
.dot { width: 12px; height: 12px; border-radius: 50%; }
.dot.red { background: #ff5f56; }
.dot.yellow { background: #ffbd2e; }
.dot.green { background: #27c93f; }
.term-title { color: #cbd5e1; font-size: 0.85rem; font-family: var(--font-mono); }
.term-close { background: none; border: none; color: #cbd5e1; font-size: 1.1rem; cursor: pointer; }
.terminal-body {
  flex: 1; padding: 1rem; font-family: var(--font-mono); font-size: 0.9rem;
  color: #4af626; overflow-y: auto; display: flex; flex-direction: column;
}
.term-welcome { color: #94a3b8; margin-bottom: 1rem; line-height: 1.4; }
.cmd-tag { color: #38bdf8; font-weight: 600; }
.terminal-input-line { display: flex; align-items: center; margin-top: auto; }
.term-prompt { color: #38bdf8; margin-right: 0.5rem; white-space: nowrap; }
.terminal-input-line input {
  flex: 1; background: transparent; border: none; color: #ffffff;
  font-family: var(--font-mono); font-size: 0.9rem; outline: none;
}

/* --- TERMINAL COLOR SCHEMES --- */
.term-theme-control {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  font-size: 0.78rem;
  color: #cbd5e1;
  font-family: var(--font-mono);
}

.term-theme-dropdown {
  background: #0f172a;
  color: #38bdf8;
  border: 1px solid #334155;
  border-radius: 6px;
  padding: 0.2rem 0.5rem;
  font-size: 0.78rem;
  font-family: var(--font-mono);
  cursor: pointer;
  outline: none;
  transition: border-color 0.2s ease;
}

.term-theme-dropdown:hover {
  border-color: #38bdf8;
}

/* 1. Light Theme (Default) */
.terminal-window[data-term-theme="light"],
.terminal-window:not([data-term-theme]) {
  background: #f8fafc;
  border-color: #cbd5e1;
}
.terminal-window[data-term-theme="light"] .terminal-header { background: #e2e8f0; border-bottom-color: #cbd5e1; }
.terminal-window[data-term-theme="light"] .terminal-body { color: #0f172a; }
.terminal-window[data-term-theme="light"] .term-prompt { color: #0369a1; }
.terminal-window[data-term-theme="light"] .term-welcome { color: #475569; }
.terminal-window[data-term-theme="light"] .cmd-tag { color: #0ea5e9; font-weight: bold; }
.terminal-window[data-term-theme="light"] .term-response { color: #0f766e; }
.terminal-window[data-term-theme="light"] .terminal-input-line input { color: #0f172a; }
.terminal-window[data-term-theme="light"] .term-theme-dropdown { background: #f8fafc; color: #0369a1; border-color: #94a3b8; }

/* 2. Dark Cyber Theme */
.terminal-window[data-term-theme="cyber-dark"] {
  background: #0d0221;
  border-color: #ff007f;
  box-shadow: 0 0 25px rgba(255, 0, 127, 0.3);
}
.terminal-window[data-term-theme="cyber-dark"] .terminal-header { background: #150535; border-bottom-color: #ff007f; }
.terminal-window[data-term-theme="cyber-dark"] .terminal-body { color: #00f0ff; }
.terminal-window[data-term-theme="cyber-dark"] .term-prompt { color: #ff007f; }
.terminal-window[data-term-theme="cyber-dark"] .term-welcome { color: #ffe600; }
.terminal-window[data-term-theme="cyber-dark"] .cmd-tag { color: #ff007f; font-weight: bold; }
.terminal-window[data-term-theme="cyber-dark"] .term-response { color: #00f0ff; }
.terminal-window[data-term-theme="cyber-dark"] .terminal-input-line input { color: #ffe600; }
.terminal-window[data-term-theme="cyber-dark"] .term-theme-dropdown { background: #150535; color: #ff007f; border-color: #ff007f; }

/* --- MILESTONE TOAST BANNER --- */
.milestone-toast-banner {
  position: fixed;
  top: -100px;
  left: 50%;
  transform: translateX(-50%);
  background: linear-gradient(135deg, #1565c0, #0284c7);
  color: #ffffff;
  padding: 0.9rem 1.8rem;
  border-radius: 50px;
  box-shadow: 0 10px 30px rgba(21, 101, 192, 0.4), 0 0 20px rgba(56, 189, 248, 0.4);
  font-family: var(--font-sans, 'Outfit', sans-serif);
  font-weight: 800;
  font-size: 0.95rem;
  z-index: 100000;
  transition: top 0.5s cubic-bezier(0.34, 1.56, 0.64, 1);
  pointer-events: none;
  border: 2px solid rgba(255, 255, 255, 0.3);
}

.milestone-toast-banner.show {
  top: 24px;
}

.milestone-toast-content {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  white-space: nowrap;
}

@keyframes spinStar {
  from { transform: scale(1) rotate(0deg); }
  to { transform: scale(1.3) rotate(20deg); }
}

/* --- MARK AS COMPLETE BUTTON & FOOTER --- */
.page-completion-footer {
  margin-top: 1.8rem;
  padding-top: 1.2rem;
  border-top: 2px dashed var(--card-border, #e0d7c3);
  display: flex;
  justify-content: center;
  align-items: center;
}

.btn-mark-complete {
  background: var(--paper-bg, #fffdf5);
  color: var(--text-ink, #1a237e);
  border: 2px solid var(--accent-blue, #1565c0);
  border-radius: 50px;
  padding: 0.65rem 1.6rem;
  font-family: var(--font-sans, 'Outfit', sans-serif);
  font-size: 0.95rem;
  font-weight: 800;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
  box-shadow: 0 3px 10px rgba(21, 101, 192, 0.12);
}

.btn-mark-complete:hover {
  background: var(--accent-blue, #1565c0);
  color: #ffffff;
  transform: translateY(-2px);
  box-shadow: 0 6px 16px rgba(21, 101, 192, 0.25);
}

.btn-mark-complete.completed {
  background: linear-gradient(135deg, #16a34a, #15803d);
  color: #ffffff;
  border-color: #15803d;
  box-shadow: 0 4px 14px rgba(22, 163, 74, 0.3);
}

.btn-mark-complete.completed:hover {
  background: linear-gradient(135deg, #15803d, #166534);
  transform: translateY(-2px);
}

body.theme-cyber .btn-mark-complete {
  background: #1e293b;
  color: #38bdf8;
  border-color: #38bdf8;
}

body.theme-cyber .btn-mark-complete:hover {
  background: #38bdf8;
  color: #0f172a;
}

body.theme-cyber .btn-mark-complete.completed {
  background: linear-gradient(135deg, #22c55e, #16a34a);
  color: #0f172a;
  border-color: #4ade80;
}

.page-item.completed-item span:first-child {
  color: #16a34a;
  font-weight: bold;
}

body.theme-cyber .page-item.completed-item span:first-child {
  color: #4ade80;
}

@keyframes spinStar {
  from { transform: scale(1) rotate(0deg); }
  to { transform: scale(1.3) rotate(20deg); }
}

/* --- PRINT / PDF EXPORT --- */

.print-only-container { display: none; }
@media print {
  body { background: #fff; color: #000; }
  .no-print, .app-header, .cyber-tools-bar, .mode-tabs-bar, .sidebar, .notebook-controls { display: none !important; }
  .main-container { display: block; }
  .notebook-workspace { padding: 0; overflow: visible; }
  #notebook-paper-view { display: none !important; }
  .print-only-container { display: block !important; }
  .ruled-paper, .interview-card, .brand-cover-page {
    page-break-after: always; break-after: page;
    box-shadow: none; border: 1px solid #ccc; margin-bottom: 0; padding: 2cm;
  }
}

/* ============================================================
   MISSING CRITICAL STYLES — SIDEBAR COLLAPSE, PAGE FLIP,
   AUTO-PLAY BUTTON, BOOKMARK BUTTON, READING MODE
   ============================================================ */

/* --- SIDEBAR COLLAPSE (Hide Sidebar / Show Sidebar) --- */
.sidebar {
  transition: width 0.35s ease, opacity 0.3s ease, padding 0.3s ease;
  overflow: hidden;
}

.main-container.sidebar-collapsed .sidebar {
  width: 0 !important;
  min-width: 0 !important;
  padding: 0 !important;
  border: none !important;
  opacity: 0;
  pointer-events: none;
}

/* --- 3D PAGE FLIP ANIMATIONS --- */
@keyframes pageFlipNext {
  0%   { opacity: 0.3; transform: perspective(1200px) rotateY(-25deg) scale(0.96); }
  100% { opacity: 1;   transform: perspective(1200px) rotateY(0deg)   scale(1); }
}

@keyframes pageFlipPrev {
  0%   { opacity: 0.3; transform: perspective(1200px) rotateY(25deg)  scale(0.96); }
  100% { opacity: 1;   transform: perspective(1200px) rotateY(0deg)   scale(1); }
}

.page-flip-next {
  animation: pageFlipNext 0.42s ease forwards;
  transform-origin: left center;
}

.page-flip-prev {
  animation: pageFlipPrev 0.42s ease forwards;
  transform-origin: right center;
}

/* --- AUTO PLAY BUTTON (▶ / ⏸️) --- */
.btn-play {
  background: var(--accent-green);
  color: #ffffff;
  border: none;
  font-weight: 700;
  transition: background 0.2s ease, transform 0.15s ease;
}

.btn-play:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(46,125,50,0.4);
}

.btn-play.playing {
  background: var(--accent-red);
  animation: pulse-play 1.2s infinite;
}

@keyframes pulse-play {
  0%, 100% { box-shadow: 0 0 0 0 rgba(211,47,47,0.5); }
  50%       { box-shadow: 0 0 0 6px rgba(211,47,47,0); }
}

/* --- BOOKMARK / SAVE BUTTON --- */
.btn-star {
  background: var(--bg-app);
  border: 2px solid var(--card-border);
  color: var(--text-ink);
  padding: 0.45rem 0.85rem;
  border-radius: 8px;
  font-weight: 600;
  font-size: 0.85rem;
  cursor: pointer;
  transition: all 0.2s ease;
}

.btn-star:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 8px rgba(0,0,0,0.15);
}

.btn-star.bookmarked {
  background: #fef08a;
  border-color: #ca8a04;
  color: #78350f;
}

/* --- READING MODE: Full-width centered page when sidebar hidden --- */
.main-container.sidebar-collapsed .notebook-workspace {
  align-items: center;
}

.main-container.sidebar-collapsed .notebook-controls {
  max-width: 860px;
  width: 100%;
}

.main-container.sidebar-collapsed #notebook-paper-view {
  max-width: 860px;
  width: 100%;
  box-shadow: 0 8px 48px rgba(0,0,0,0.22);
  border-radius: 12px;
}

/* --- TERM RESPONSE LINES --- */
.term-cmd-line { margin-top: 0.5rem; color: #94a3b8; }
/* --- READING PROGRESS CARD (Exact Match to User Request Image 1) --- */
.reading-progress-card {
  background: var(--paper-bg, #fffdf5);
  border: 1.5px solid var(--card-border, #e0d7c3);
  border-radius: 12px;
  padding: 0.85rem 1.2rem;
  margin: 0.8rem 0 1rem 0;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.04);
  width: 100%;
}

.progress-card-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 0.6rem;
}

.progress-card-title {
  font-weight: 800;
  color: var(--text-ink, #1a237e);
  font-size: 0.98rem;
  font-family: var(--font-sans, 'Outfit', sans-serif);
  letter-spacing: -0.01em;
}

.progress-card-pct {
  font-weight: 800;
  color: var(--text-ink, #1a237e);
  font-size: 0.98rem;
  font-family: var(--font-sans, 'Outfit', sans-serif);
}

.progress-track-bg {
  background: rgba(0, 0, 0, 0.05);
  border: 1px solid var(--card-border, #e0d7c3);
  height: 14px;
  border-radius: 999px;
  overflow: hidden;
  width: 100%;
}

.progress-fill-bar {
  height: 100%;
  width: 0%;
  background: linear-gradient(90deg, #1565c0, #0284c7);
  border-radius: 999px;
  transition: width 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

body.theme-cyber .reading-progress-card {
  background: #111827;
  border-color: #1e293b;
}

body.theme-cyber .progress-card-title,
body.theme-cyber .progress-card-pct {
  color: #38bdf8;
}

body.theme-cyber .progress-track-bg {
  background: #0f172a;
  border-color: #1e293b;
}

/* --- INTERACTIVE 3D FLIP FLASHCARDS (Exact Match to User Request Image 2) --- */
.flashcard-3d-wrapper {
  perspective: 1200px;
  cursor: pointer;
  width: 100%;
  margin-bottom: 1.5rem;
}

.flashcard-inner {
  position: relative;
  width: 100%;
  transition: transform 0.6s cubic-bezier(0.4, 0, 0.2, 1);
  transform-style: preserve-3d;
}

.flashcard-3d-wrapper.flipped .flashcard-inner {
  transform: rotateY(180deg);
}

.flashcard-front,
.flashcard-back {
  width: 100%;
  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;
  border-radius: 14px;
  background: var(--paper-bg, #fffdf5);
  border: 2px solid var(--card-border, #e0d7c3);
  box-shadow: 0 6px 24px rgba(0, 0, 0, 0.06);
  padding: 2rem 2.2rem;
  box-sizing: border-box;
}

.flashcard-front {
  min-height: 320px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.flashcard-back {
  position: absolute;
  top: 0;
  left: 0;
  transform: rotateY(180deg);
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.3s ease;
}

.flashcard-3d-wrapper.flipped .flashcard-front {
  position: absolute;
  top: 0;
  left: 0;
  opacity: 0;
  pointer-events: none;
}

.flashcard-3d-wrapper.flipped .flashcard-back {
  position: relative;
  opacity: 1;
  pointer-events: auto;
}

.flashcard-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 1rem;
  width: 100%;
}

.flashcard-question-title {
  font-family: var(--font-sans, 'Outfit', sans-serif);
  font-size: 1.25rem;
  font-weight: 800;
  color: var(--text-ink, #1a237e);
  text-transform: uppercase;
  line-height: 1.4;
  letter-spacing: -0.01em;
  margin: 0 0 0.5rem 0;
}

.flashcard-question-badge {
  background: #d32f2f;
  color: #ffffff;
  border-radius: 4px;
  font-size: 0.72rem;
  font-weight: 800;
  padding: 0.2rem 0.55rem;
  text-transform: uppercase;
  display: inline-block;
  letter-spacing: 0.04em;
}

.flashcard-logo-badge {
  width: 60px;
  height: 60px;
  border-radius: 10px;
  border: 1.5px solid var(--card-border, #e0d7c3);
  box-shadow: 0 3px 10px rgba(0, 0, 0, 0.08);
  object-fit: cover;
  flex-shrink: 0;
}

.flashcard-click-hint {
  text-align: center;
  font-weight: 700;
  font-size: 0.9rem;
  color: #78716c;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.4rem;
  margin-top: 3rem;
  user-select: none;
  transition: color 0.2s ease;
}

.flashcard-3d-wrapper:hover .flashcard-click-hint {
  color: var(--accent-blue, #1565c0);
}

.flashcard-flip-badge {
  background: var(--accent-blue, #1565c0);
  color: #ffffff;
  border-radius: 20px;
  font-size: 0.78rem;
  font-weight: 700;
  padding: 0.25rem 0.75rem;
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  flex-shrink: 0;
}

/* Cyber Theme for Flashcards */
body.theme-cyber .flashcard-front,
body.theme-cyber .flashcard-back {
  background: #111827;
  border-color: #1e293b;
  box-shadow: 0 6px 24px rgba(0, 0, 0, 0.4);
}

body.theme-cyber .flashcard-question-title {
  color: #f8fafc;
}

body.theme-cyber .flashcard-click-hint {
  color: #94a3b8;
}

body.theme-cyber .flashcard-3d-wrapper:hover .flashcard-click-hint {
  color: #38bdf8;
}

/* Search Term Highlights */
mark.highlight {
  background-color: #fff9c4 !important;
  color: #1a237e !important;
  padding: 0.1em 0.3em;
  border-radius: 4px;
  box-shadow: 0 0 6px rgba(255, 249, 196, 0.9);
  animation: highlightFade 0.4s ease-in-out;
}

@keyframes highlightFade {
  from { background-color: #ffe082; }
  to { background-color: #fff9c4; }
}

body.theme-cyber mark.highlight {
  background-color: #fef08a !important;
  color: #0f172a !important;
}

/* ============================================================
   📱 MOBILE RESPONSIVE STYLES
   Breakpoints: ≤1024px (tablet), ≤768px (mobile), ≤480px (phone)
   ============================================================ */

/* ── Large Desktop & Tablet (≤1200px) ── */
@media (max-width: 1200px) {
  .header-badge-group { display: none; }
  .mode-tabs-bar { justify-content: center; }
}

/* ── Tablet (≤1024px) ── */
@media (max-width: 1024px) {
  .sidebar { width: 260px; }
  .app-header { padding: 0.5rem 1rem; }
  .header-left h1 { font-size: 1.05rem; }
  .brand-tagline { font-size: 0.8rem; }
  .header-subtitle { font-size: 0.72rem; }
  .notebook-workspace { padding: 1rem 1.2rem; }
  .ruled-paper { padding: 1.5rem; font-size: 0.92rem; }
}

/* ── Mobile (≤768px) ── */
@media (max-width: 768px) {

  /* Header collapses to icon + title only */
  .app-header {
    padding: 0.5rem 0.8rem;
    flex-wrap: wrap;
    gap: 0.4rem;
  }

  .header-left h1 { font-size: 0.95rem; }
  .header-subtitle { display: none; }
  .brand-header-logo { width: 38px; height: 38px; }

  .header-profiles {
    gap: 0.3rem;
    margin-left: 0.3rem;
    margin-right: 0.3rem;
  }
  .profile-pill {
    padding: 0.35rem 0.55rem;
    font-size: 0.75rem;
  }

  .header-right {
    gap: 0.3rem;
  }

  .btn-action {
    padding: 0.35rem 0.55rem;
    font-size: 0.78rem;
  }

  /* Cyber tools bar wraps cleanly */
  .cyber-tools-bar { gap: 0.6rem; font-size: 0.72rem; padding: 0.25rem 0.6rem; }

  /* Mode tabs become scrollable row on mobile */
  .mode-tabs-bar {
    padding: 0.4rem 0.6rem;
  }
  .mode-tabs-container {
    overflow-x: auto;
    justify-content: flex-start;
    -webkit-overflow-scrolling: touch;
  }
  .mode-tab { font-size: 0.8rem; padding: 0.4rem 0.8rem; white-space: nowrap; flex: none; }

  /* Sidebar: hidden by default on mobile — slides in as drawer */
  .sidebar {
    position: fixed;
    top: 0; left: 0; bottom: 0;
    z-index: 500;
    width: 280px;
    transform: translateX(-100%);
    transition: transform 0.3s ease;
    box-shadow: 4px 0 20px rgba(0,0,0,0.25);
  }

  /* When sidebar is shown on mobile (toggled via button) */
  .sidebar.mobile-open {
    transform: translateX(0);
  }

  /* Overlay behind sidebar drawer */
  .sidebar-overlay {
    display: none;
    position: fixed;
    inset: 0;
    background: rgba(0,0,0,0.45);
    z-index: 499;
    backdrop-filter: blur(2px);
  }

  .sidebar-overlay.active { display: block; }

  /* Main content fills full width */
  .main-container { flex-direction: column; }
  .notebook-workspace { padding: 0.5rem 0.4rem; width: 100%; }

  /* Toolbar: stack into 2 rows */
  .notebook-controls {
    flex-wrap: wrap;
    gap: 0.5rem;
    padding: 0.5rem 0.7rem;
    justify-content: center;
  }

  .toolbar-left-group { width: 100%; justify-content: center; }
  .page-switcher { justify-content: center; }
  .quick-tags { justify-content: center; width: 100%; }

  .page-indicator input { width: 48px; font-size: 0.9rem; }

  /* --- MOBILE RULED PAPER & TEXT ALIGNMENT FIX --- */
  .ruled-paper, .interview-card {
    padding: 1rem 0.8rem 1.5rem 2.8rem !important; /* Keep text to the right of red margin line */
    font-size: 0.88rem;
    line-height: 28px;
    border-radius: 8px;
    margin: 0;
    background-image: repeating-linear-gradient(
      var(--paper-bg) 0px,
      var(--paper-bg) 27px,
      var(--paper-line) 28px
    );
  }

  /* Reposition Red Vertical Margin Line on Mobile */
  .ruled-paper::before {
    left: 1.8rem !important; /* Move red line to 1.8rem so it sits to the left of text */
  }

  /* Watermark Stamp positioning on Mobile */
  .brand-watermark-stamp {
    width: 42px !important;
    top: 0.5rem !important;
    right: 0.5rem !important;
    opacity: 0.35 !important;
  }

  /* Page Title Header Row on Mobile */
  .page-header-row {
    flex-direction: column !important;
    padding-right: 0 !important;
    gap: 0.4rem !important;
    margin-bottom: 0.8rem !important;
    align-items: flex-start !important;
  }

  .concept-title-box h2 {
    font-size: 1.15rem !important;
    line-height: 1.35 !important;
    word-break: break-word !important;
  }

  .page-stamp {
    position: relative !important;
    top: 0 !important;
    right: 0 !important;
    align-self: flex-start !important;
    font-size: 0.78rem !important;
    padding: 0.2rem 0.6rem !important;
  }

  /* Section blocks stack vertically */
  .section-block { margin-bottom: 0.8rem; }
  .section-label { font-size: 0.75rem; }

  .handwritten-text { font-size: 0.95rem; line-height: 1.5; }

  /* Terminal modal full screen */
  .terminal-window {
    width: 100%;
    height: 100%;
    border-radius: 0;
    max-width: 100%;
  }

  /* Cover page adjustments */
  .cover-logo-hero { width: 80px; height: 80px; }
  .cover-title { font-size: 1.5rem; }
  .cover-badge-row { gap: 0.5rem; }
  .cover-badge { padding: 0.4rem 0.7rem; font-size: 0.78rem; }

  /* Sidebar collapsed reading mode — same as full width on mobile */
  .main-container.sidebar-collapsed .notebook-controls,
  .main-container.sidebar-collapsed #notebook-paper-view {
    max-width: 100%;
  }
}

/* ── Phone (≤480px) ── */
@media (max-width: 480px) {
  .app-header {
    padding: 0.5rem;
    gap: 0.4rem;
  }

  .header-left h1 { font-size: 0.9rem; }
  .brand-header-logo { width: 34px; height: 34px; }
  .header-subtitle { font-size: 0.72rem; }

  /* Scrollable Profile Pills on Phone */
  .header-profiles {
    width: 100%;
    overflow-x: auto;
    flex-wrap: nowrap;
    justify-content: flex-start;
    padding-bottom: 4px;
    -webkit-overflow-scrolling: touch;
  }

  .profile-pill {
    padding: 0.35rem 0.6rem;
    font-size: 0.75rem;
    flex-shrink: 0;
  }
  .profile-label { display: inline; }

  /* Header action buttons scrollable */
  .header-right {
    width: 100%;
    overflow-x: auto;
    flex-wrap: nowrap;
    justify-content: flex-start;
    padding-bottom: 4px;
    -webkit-overflow-scrolling: touch;
  }

  .btn-action {
    padding: 0.35rem 0.65rem;
    font-size: 0.75rem;
    flex-shrink: 0;
  }

  /* Mode tabs scrollable bar */
  .mode-tabs-bar {
    padding: 0.4rem 0.5rem;
  }

  .mode-tabs-badges-row {
    overflow-x: auto;
    flex-wrap: nowrap;
    padding-bottom: 4px;
    -webkit-overflow-scrolling: touch;
  }

  .mode-tabs-container {
    overflow-x: auto;
    flex-wrap: nowrap;
    justify-content: flex-start;
    padding: 0.2rem;
    -webkit-overflow-scrolling: touch;
  }

  .mode-tab {
    flex-shrink: 0;
    font-size: 0.75rem;
    padding: 0.35rem 0.65rem;
  }

  .ruled-paper, .interview-card {
    padding: 0.8rem 0.6rem 1.2rem 2.6rem !important; /* Keeps text to the right of red margin line */
    font-size: 0.83rem;
  }

  .ruled-paper::before {
    left: 1.6rem !important; /* Move red line to 1.6rem */
  }

  .page-indicator input { width: 40px; }

  .nav-arrow { padding: 0.35rem 0.6rem; font-size: 0.85rem; }

  /* Stack SVG diagrams below text on phones */
  .svg-diagram { max-width: 100%; }

  .cmd-box { font-size: 0.78rem; padding: 0.6rem; overflow-x: auto; }
  .syntax-box { font-size: 0.78rem; }
}

/* ── Floating Mobile Nav Bar ── */
/* A sticky bottom nav for phone users (≤768px) */
@media (max-width: 768px) {
  .mobile-bottom-nav {
    display: flex;
    position: fixed;
    bottom: 0; left: 0; right: 0;
    background: var(--paper-bg);
    border-top: 2px solid var(--card-border);
    z-index: 400;
    padding: 0.4rem 1rem;
    justify-content: space-around;
    align-items: center;
    box-shadow: 0 -4px 16px rgba(0,0,0,0.12);
  }

  .mobile-nav-btn {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.15rem;
    background: none;
    border: none;
    color: var(--text-ink);
    font-size: 0.65rem;
    font-weight: 700;
    cursor: pointer;
    padding: 0.3rem 0.5rem;
    border-radius: 8px;
    transition: background 0.15s;
  }

  .mobile-nav-btn .nav-icon { font-size: 1.3rem; }
  .mobile-nav-btn:active { background: var(--bg-app); }

  /* Pad main content so it's not hidden behind bottom nav */
  .main-container { padding-bottom: var(--mobile-bottom-nav-space); }
}

/* --- PRINT & PDF EXPORT STYLES (CLEAN A4 PAGE BREAKS & PERFECT LINE FITTING) --- */
@media print {
  body {
    background: #ffffff !important;
    color: #0f172a !important;
    font-size: 11pt !important;
  }

  .no-print, header, nav, .sidebar, .sidebar-overlay, .mode-tabs-bar, .notebook-controls, .mobile-bottom-nav, #terminal-modal, #pdf-export-choice-modal, #pdf-progress-modal {
    display: none !important;
  }

  .main-container {
    padding: 0 !important;
    margin: 0 !important;
    width: 100% !important;
  }

  .notebook-workspace {
    padding: 0 !important;
    width: 100% !important;
  }

  #full-pdf-container {
    display: block !important;
    width: 100% !important;
  }

  .ruled-paper, .interview-card {
    page-break-after: always !important;
    break-after: page !important;
    page-break-inside: avoid !important;
    break-inside: avoid !important;
    margin: 0 !important;
    padding: 2.5rem !important;
    border: none !important;
    box-shadow: none !important;
    min-height: 95vh !important;
    background: #ffffff !important;
    color: #0f172a !important;
  }

  .cmd-box, .syntax-box, pre, code {
    white-space: pre-wrap !important;
    word-break: break-all !important;
    background: #f8fafc !important;
    color: #0f172a !important;
    border: 1px solid #cbd5e1 !important;
  }
}

}

/* Hide mobile bottom nav on desktop */
@media (min-width: 769px) {
  .mobile-bottom-nav { display: none; }
}

/* ============================================================
/* ============================================================
   CINEMATIC LINUX PENGUIN INTRO SPLASH OVERLAY
   ============================================================ */
.splash-screen-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100dvh;
  min-height: 100vh;
  z-index: 999999;
  display: flex;
  justify-content: center;
  align-items: center;
  overflow: hidden;
  background: #060911 !important;
  opacity: 1;
  visibility: visible;
  transition: opacity 0.75s cubic-bezier(0.4, 0, 0.2, 1), visibility 0.75s cubic-bezier(0.4, 0, 0.2, 1);
  will-change: opacity, visibility;
}

.splash-screen-overlay.fade-out {
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
}

.splash-video {
  width: 100%;
  height: 100%;
  max-width: 100vw;
  max-height: 100dvh;
  object-fit: cover;
  object-position: center center;
  display: block;
  pointer-events: none;
  background: #060911;
}

/* Device Specific Optimizations */
@media (min-width: 769px) {
  .splash-video-desktop { display: block !important; }
  .splash-video-mobile { display: none !important; }
}

@media (max-width: 768px) {
  .splash-screen-overlay {
    height: 100dvh;
    background: #060911 !important;
  }
  .splash-video-desktop { display: none !important; }
  .splash-video-mobile { 
    display: block !important; 
    object-fit: cover !important; 
    object-position: center center !important;
  }
}

.splash-audio-badge {
  position: absolute;
  top: max(16px, env(safe-area-inset-top));
  right: 16px;
  z-index: 1000000;
  display: flex;
  align-items: center;
  gap: 6px;
  background: rgba(11, 19, 36, 0.85);
  border: 1px solid rgba(56, 189, 248, 0.5);
  color: #38bdf8;
  font-family: 'Fira Code', monospace;
  font-size: 0.78rem;
  font-weight: 600;
  padding: 6px 14px;
  border-radius: 20px;
  backdrop-filter: blur(12px);
  cursor: pointer;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.4), 0 0 15px rgba(56, 189, 248, 0.2);
  transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
  user-select: none;
}

.splash-audio-badge:hover {
  background: rgba(15, 23, 42, 0.95);
  border-color: #38bdf8;
  box-shadow: 0 0 20px rgba(56, 189, 248, 0.6);
  transform: scale(1.05);
}

.splash-audio-badge.unmuted {
  border-color: rgba(74, 222, 128, 0.6);
  color: #4ade80;
  box-shadow: 0 0 15px rgba(74, 222, 128, 0.3);
}

/* ============================================================
   A–Z MASTER CHEATSHEET STYLES
   ============================================================ */
.cs-master-container {
  display: flex;
  flex-direction: column;
  gap: 1.2rem;
}

/* CHEAT SHEET SUB-TAB SWITCHER */
.cs-tab-switcher {
  display: flex;
  gap: 0.5rem;
  overflow-x: auto;
  padding: 0.4rem 0.6rem;
  background: var(--paper-bg);
  border: 1.5px solid var(--card-border);
  border-radius: 12px;
  box-shadow: 0 4px 12px rgba(0,0,0,0.02);
}

.cs-tab-btn {
  white-space: nowrap;
  background: var(--bg-app);
  border: 1px solid var(--card-border);
  color: var(--text-dark);
  font-family: 'Outfit', sans-serif;
  font-size: 0.85rem;
  font-weight: 700;
  padding: 0.5rem 1rem;
  border-radius: 8px;
  cursor: pointer;
  transition: all 0.2s ease;
}

.cs-tab-btn:hover {
  background: var(--accent-blue);
  color: #ffffff;
  border-color: var(--accent-blue);
}

.cs-tab-btn.active {
  background: var(--accent-blue);
  color: #ffffff;
  border-color: var(--accent-blue);
  box-shadow: 0 4px 12px rgba(56, 189, 248, 0.3);
}

.cs-sub-section {
  display: none;
  animation: csFadeIn 0.3s ease forwards;
}

.cs-sub-section.active {
  display: block;
}

@keyframes csFadeIn {
  from { opacity: 0; transform: translateY(6px); }
  to { opacity: 1; transform: translateY(0); }
}

.cs-stats-row {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 1rem;
}

.cs-stat-card {
  background: var(--paper-bg);
  border: 1.5px solid var(--card-border);
  border-radius: 12px;
  padding: 1rem 1.2rem;
  display: flex;
  align-items: center;
  gap: 1rem;
  box-shadow: 0 4px 12px rgba(0,0,0,0.03);
}

.cs-stat-icon {
  font-size: 2rem;
}

.cs-stat-val {
  font-family: 'Outfit', sans-serif;
  font-size: 1.4rem;
  font-weight: 800;
  color: var(--accent-blue);
  line-height: 1;
}

.cs-stat-lbl {
  font-size: 0.78rem;
  font-weight: 700;
  color: #64748b;
  margin-top: 0.2rem;
}

.cs-section-box {
  background: var(--paper-bg);
  border: 1.5px solid var(--card-border);
  border-radius: 14px;
  padding: 1.4rem;
  box-shadow: 0 4px 16px rgba(0,0,0,0.04);
}

.cs-section-title {
  font-family: 'Outfit', sans-serif;
  font-size: 1.15rem;
  font-weight: 800;
  color: var(--accent-blue);
  margin-bottom: 0.8rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.cs-top25-grid {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.cs-top25-btn {
  background: var(--bg-app);
  border: 1px solid var(--card-border);
  color: var(--text-ink);
  font-family: 'Fira Code', monospace;
  font-size: 0.82rem;
  font-weight: 700;
  padding: 0.4rem 0.8rem;
  border-radius: 8px;
  cursor: pointer;
  transition: all 0.2s ease;
}

.cs-top25-btn:hover {
  background: var(--accent-blue);
  color: #ffffff;
  border-color: var(--accent-blue);
  transform: translateY(-2px);
}

.cs-az-bar {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem;
  justify-content: center;
}

.cs-az-btn {
  width: 32px;
  height: 32px;
  display: inline-flex;
  justify-content: center;
  align-items: center;
  background: var(--bg-app);
  border: 1px solid var(--card-border);
  border-radius: 6px;
  font-weight: 800;
  font-size: 0.82rem;
  color: var(--accent-blue);
  cursor: pointer;
  transition: all 0.15s ease;
}

.cs-az-btn:hover {
  background: var(--accent-blue);
  color: #ffffff;
  transform: scale(1.1);
}

.cs-controls-bar {
  display: flex;
  flex-direction: column;
  gap: 0.9rem;
  background: var(--paper-bg);
  border: 1.5px solid var(--card-border);
  border-radius: 14px;
  padding: 1.2rem;
}

.cs-search-input {
  width: 100%;
  padding: 0.75rem 1.2rem;
  border-radius: 10px;
  border: 1.5px solid var(--card-border);
  background: var(--bg-app);
  color: var(--text-ink);
  font-size: 0.92rem;
  outline: none;
  transition: border-color 0.2s ease;
}

.cs-search-input:focus {
  border-color: var(--accent-blue);
}

.cs-filter-pills {
  display: flex;
  gap: 0.45rem;
  overflow-x: auto;
  padding-bottom: 0.4rem;
  scrollbar-width: thin;
}

.cs-pill {
  white-space: nowrap;
  background: var(--bg-app);
  border: 1px solid var(--card-border);
  color: var(--text-dark);
  font-size: 0.78rem;
  font-weight: 700;
  padding: 0.35rem 0.85rem;
  border-radius: 20px;
  cursor: pointer;
  transition: all 0.2s ease;
}

.cs-pill.active {
  background: var(--accent-blue);
  color: #ffffff;
  border-color: var(--accent-blue);
}

.cs-cards-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(360px, 1fr));
  gap: 1.2rem;
}

.cs-card {
  background: var(--paper-bg);
  border: 1.5px solid var(--card-border);
  border-radius: 14px;
  padding: 1.4rem;
  box-shadow: 0 4px 16px rgba(0,0,0,0.03);
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  position: relative;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.cs-card:hover {
  transform: translateY(-3px);
  box-shadow: 0 8px 24px rgba(0,0,0,0.08);
}

.cs-card-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 0.5rem;
  margin-bottom: 0.6rem;
}

.cs-card-cat {
  font-size: 0.74rem;
  font-weight: 800;
  color: var(--accent-blue);
  text-transform: uppercase;
}

.cs-card-badges {
  display: flex;
  gap: 0.35rem;
  align-items: center;
}

.cs-badge {
  font-size: 0.68rem;
  font-weight: 700;
  padding: 0.2rem 0.55rem;
  border-radius: 12px;
}

.cs-badge-beg { background: rgba(34, 197, 94, 0.12); color: #15803d; border: 1px solid #22c55e; }
.cs-badge-int { background: rgba(245, 158, 11, 0.12); color: #b45309; border: 1px solid #f59e0b; }
.cs-badge-adv { background: rgba(239, 68, 68, 0.12); color: #b91c1c; border: 1px solid #ef4444; }
.cs-badge-changing { background: rgba(225, 29, 72, 0.15); color: #e11d48; border: 1px solid #e11d48; font-weight: 800; }

.cs-cmd-box {
  background: var(--bg-app);
  border: 1px solid var(--card-border);
  border-radius: 8px;
  padding: 0.75rem 1rem;
  margin: 0.6rem 0 0.8rem 0;
  position: relative;
  overflow-x: auto;
}

.cs-cmd-code {
  font-family: 'Fira Code', monospace;
  font-size: 0.86rem;
  font-weight: 700;
  color: var(--accent-red);
  white-space: pre-wrap;
  word-break: break-all;
}

.cs-btn-copy {
  position: absolute;
  top: 0.4rem;
  right: 0.4rem;
  background: var(--accent-blue);
  color: #ffffff;
  border: none;
  border-radius: 6px;
  padding: 0.25rem 0.6rem;
  font-size: 0.72rem;
  font-weight: 700;
  cursor: pointer;
  transition: all 0.15s ease;
}

.cs-btn-copy:hover {
  transform: scale(1.05);
}

.cs-btn-copy.copied {
  background: #22c55e;
}

.cs-card-detail {
  font-size: 0.84rem;
  color: var(--text-dark);
  line-height: 1.48;
  margin-bottom: 0.5rem;
}

.cs-card-detail strong {
  color: var(--text-ink);
}

.cs-card-footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-top: 0.8rem;
  padding-top: 0.6rem;
  border-top: 1px dashed var(--card-border);
}

.cs-btn-star {
  background: transparent;
  border: none;
  font-size: 1.1rem;
  cursor: pointer;
  opacity: 0.5;
  transition: opacity 0.2s ease, transform 0.2s ease;
}

.cs-btn-star.starred {
  opacity: 1;
  transform: scale(1.2);
}

/* =============================================================
   FEATURES.JS — Enhancement UI Styles (Zero extra buttons)
   ============================================================= */

/* --- FONT STYLE MODES --- */
body.font-sans { --font-hand: 'Outfit', sans-serif; font-family: 'Outfit', sans-serif !important; }
body.font-dyslexia { --font-hand: 'Comic Sans MS', 'Trebuchet MS', sans-serif; font-family: 'Comic Sans MS', 'Trebuchet MS', sans-serif !important; letter-spacing: 0.04em; word-spacing: 0.12em; line-height: 1.8; }

/* --- HIGH CONTRAST MODES --- */
body.contrast-high-dark { --bg-app: #000; --paper-bg: #0a0a0a; --text-ink: #fff; --text-dark: #f0f0f0; --accent-blue: #00d4ff; --card-border: #444; --paper-line: #222; filter: contrast(1.2); }
body.contrast-high-light { --bg-app: #fff; --paper-bg: #fff; --text-ink: #000; --text-dark: #000; --accent-blue: #0000cc; --card-border: #000; filter: contrast(1.4); }

/* --- DAILY STREAK CHIP --- */
.streak-chip-bar { display: flex; align-items: center; gap: 0.5rem; padding: 0.5rem 0.8rem; background: linear-gradient(135deg,#fff3cd,#ffe082); border-radius: 10px; margin: 0 0.5rem 0.5rem; font-size: 0.82rem; font-weight: 700; color: #92400e; box-shadow: 0 2px 8px rgba(251,191,36,0.3); }
.streak-flame { font-size: 1.1rem; animation: flicker 1.2s infinite alternate; }
@keyframes flicker { from { transform: scale(1); } to { transform: scale(1.15) rotate(-3deg); } }
.streak-label { flex: 1; }
.streak-badge-btn { cursor: pointer; background: #1565c0; color: #fff; border: none; padding: 0.2rem 0.55rem; border-radius: 6px; font-size: 0.75rem; font-weight: 700; transition: background 0.2s; }
.streak-badge-btn:hover { background: #0d47a1; }

/* --- BADGE TOAST --- */
.badge-toast { position: fixed; bottom: 2rem; right: 2rem; z-index: 99999; background: linear-gradient(135deg,#1565c0,#0d47a1); color: #fff; border-radius: 14px; padding: 1rem 1.2rem; display: flex; align-items: center; gap: 1rem; box-shadow: 0 8px 32px rgba(21,101,192,0.5); transform: translateX(120%); transition: transform 0.4s cubic-bezier(0.175,0.885,0.32,1.275); max-width: 320px; }
.badge-toast.show { transform: translateX(0); }
.badge-toast-icon { font-size: 2.2rem; }
.badge-toast-title { font-size: 0.72rem; text-transform: uppercase; letter-spacing: 0.08em; opacity: 0.8; }
.badge-toast-name { font-size: 1rem; font-weight: 800; }
.badge-toast-desc { font-size: 0.78rem; opacity: 0.85; margin-top: 0.15rem; }

/* --- SHARED MODAL STYLES --- */
.feat-modal-overlay { position: fixed; inset: 0; background: rgba(0,0,0,0.75); z-index: 99998; display: flex; align-items: center; justify-content: center; padding: 1rem; backdrop-filter: blur(4px); }
.feat-modal-card { background: var(--paper-bg); border: 2px solid var(--accent-blue); border-radius: 18px; width: 100%; max-width: 780px; max-height: 88vh; display: flex; flex-direction: column; box-shadow: 0 24px 64px rgba(0,0,0,0.4); overflow: hidden; }
.feat-modal-header { display: flex; justify-content: space-between; align-items: center; padding: 1rem 1.4rem; border-bottom: 1px solid var(--card-border); font-weight: 800; font-size: 1.1rem; color: var(--accent-blue); font-family: var(--font-sans); }
.feat-modal-close { background: none; border: none; font-size: 1.3rem; cursor: pointer; color: var(--text-dark); opacity: 0.7; transition: opacity 0.2s; }
.feat-modal-close:hover { opacity: 1; }
.feat-modal-body { padding: 1.2rem 1.4rem; overflow-y: auto; flex: 1; }
.feat-modal-hint { font-size: 0.85rem; color: #64748b; margin-bottom: 1rem; }

/* --- BADGES GRID & CUSTOM BADGE GRAPHICS --- */
.badges-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(150px, 1fr)); gap: 1rem; }
.badge-card { text-align: center; padding: 1.1rem 0.7rem; border-radius: 14px; border: 2px solid transparent; transition: all 0.25s cubic-bezier(0.34, 1.56, 0.64, 1); display: flex; flex-direction: column; align-items: center; justify-content: space-between; }
.badge-card:hover { transform: translateY(-4px) scale(1.02); }
.badge-earned { background: linear-gradient(135deg, rgba(34, 197, 94, 0.08), rgba(16, 185, 129, 0.04)); border-color: rgba(34, 197, 94, 0.4); box-shadow: 0 4px 14px rgba(34, 197, 94, 0.12); }
.badge-locked { background: var(--bg-app); border-color: var(--card-border); opacity: 0.75; }
.badge-img-wrapper { position: relative; width: 92px; height: 92px; margin: 0 auto 0.6rem auto; display: flex; align-items: center; justify-content: center; }
.badge-img { width: 100%; height: 100%; object-fit: contain; filter: drop-shadow(0 6px 12px rgba(0, 0, 0, 0.25)); transition: transform 0.3s cubic-bezier(0.34, 1.56, 0.64, 1), filter 0.3s ease; }
.badge-card:hover .badge-img:not(.badge-img-locked) { transform: scale(1.14) rotate(2deg); filter: drop-shadow(0 10px 22px rgba(34, 197, 94, 0.45)); }
.badge-img-locked { filter: grayscale(1) opacity(0.4) contrast(0.85); }
.badge-lock-overlay { position: absolute; bottom: -2px; right: 2px; background: rgba(15, 23, 42, 0.9); color: #fbbf24; font-size: 0.8rem; padding: 0.2rem 0.45rem; border-radius: 50%; border: 1.5px solid rgba(255, 255, 255, 0.25); box-shadow: 0 3px 8px rgba(0, 0, 0, 0.5); }
.badge-name { font-weight: 800; font-size: 0.88rem; color: var(--text-dark); margin-top: 0.2rem; }
.badge-desc { font-size: 0.73rem; color: #64748b; margin-top: 0.2rem; line-height: 1.25; }
.badge-status-tag { margin-top: 0.6rem; font-size: 0.65rem; font-weight: 800; letter-spacing: 0.08em; padding: 0.2rem 0.55rem; border-radius: 12px; display: inline-block; }
.badge-earned .badge-status-tag { background: rgba(34, 197, 94, 0.15); color: #16a34a; border: 1px solid rgba(34, 197, 94, 0.4); }
.badge-locked .badge-status-tag { background: rgba(100, 116, 139, 0.12); color: #64748b; border: 1px solid rgba(100, 116, 139, 0.25); }
.badge-toast-img-wrap { width: 48px; height: 48px; flex-shrink: 0; }
.badge-toast-img { width: 100%; height: 100%; object-fit: contain; filter: drop-shadow(0 4px 8px rgba(0,0,0,0.35)); }
/* --- THREAT TICKER --- */
.threat-ticker { display: flex; align-items: center; gap: 0.8rem; background: linear-gradient(90deg,#0f172a,#1e293b); color: #e2e8f0; padding: 0.35rem 1rem; font-size: 0.8rem; font-family: var(--font-mono); overflow: hidden; z-index: 100; border-bottom: 1px solid #334155; }
.ticker-label { background: #ef4444; color: #fff; font-weight: 800; font-size: 0.72rem; padding: 0.1rem 0.5rem; border-radius: 4px; white-space: nowrap; letter-spacing: 0.05em; }
.ticker-scroll { flex: 1; transition: opacity 0.4s ease; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.ticker-close { background: none; border: none; color: #94a3b8; cursor: pointer; font-size: 0.9rem; padding: 0.1rem 0.3rem; border-radius: 4px; transition: color 0.2s; white-space: nowrap; }
.ticker-close:hover { color: #ef4444; }

/* --- STUDY NOTES PANEL --- */
.study-notes-panel { margin-top: 2rem; border-top: 2px dashed var(--paper-line); padding-top: 1rem; }
.notes-header { display: flex; justify-content: space-between; align-items: center; font-weight: 700; font-size: 0.9rem; color: var(--text-ink); margin-bottom: 0.5rem; }
.notes-hint { font-size: 0.72rem; color: #94a3b8; font-weight: 400; }
.notes-textarea { width: 100%; min-height: 90px; padding: 0.75rem; border-radius: 10px; border: 1.5px solid var(--card-border); background: var(--paper-bg); color: var(--text-dark); font-family: var(--font-hand); font-size: 0.9rem; resize: vertical; outline: none; transition: border-color 0.2s; box-sizing: border-box; }
.notes-textarea:focus { border-color: var(--accent-blue); }
.notes-textarea::placeholder { color: #94a3b8; }

/* --- FUZZY SEARCH DROPDOWN --- */
.search-results-dropdown { position: absolute; top: calc(100% + 4px); left: 0; right: 0; background: var(--paper-bg); border: 1.5px solid var(--accent-blue); border-radius: 10px; box-shadow: 0 8px 24px rgba(0,0,0,0.15); z-index: 9999; max-height: 280px; overflow-y: auto; }
.search-results-dropdown.hidden { display: none; }
.search-result-item { padding: 0.55rem 0.9rem; font-size: 0.83rem; color: var(--text-dark); cursor: pointer; transition: background 0.15s; border-bottom: 1px solid var(--card-border); white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.search-result-item:last-child { border-bottom: none; }
.search-result-item:hover { background: rgba(21,101,192,0.08); color: var(--accent-blue); }
.search-no-result { padding: 1rem; text-align: center; font-size: 0.85rem; color: #94a3b8; }

/* --- CVE LAUNCH CHIP (inside Log Parser Lab) --- */
.cve-launch-chip { margin-bottom: 1rem; }
.cve-chip-btn { width: 100%; padding: 0.75rem 1.2rem; background: linear-gradient(135deg,#1a1a2e,#16213e); color: #38bdf8; border: 1.5px solid #38bdf8; border-radius: 10px; font-size: 0.9rem; font-weight: 700; font-family: var(--font-mono); cursor: pointer; transition: all 0.2s; text-align: left; }
.cve-chip-btn:hover { background: #1565c0; color: #fff; border-color: #1565c0; box-shadow: 0 4px 16px rgba(21,101,192,0.4); }

/* --- CVE MODAL CARDS --- */
.cve-search-input { width: 100%; padding: 0.75rem 1rem; border-radius: 10px; border: 1.5px solid var(--card-border); background: var(--bg-app); color: var(--text-dark); font-size: 0.95rem; margin-bottom: 1rem; outline: none; box-sizing: border-box; transition: border-color 0.2s; }
.cve-search-input:focus { border-color: var(--accent-blue); }
.cve-results-list { display: flex; flex-direction: column; gap: 0.8rem; }
.cve-card { background: var(--bg-app); border: 1.5px solid var(--card-border); border-radius: 12px; padding: 1rem 1.2rem; }
.cve-card-header { display: flex; align-items: center; gap: 0.6rem; flex-wrap: wrap; margin-bottom: 0.4rem; }
.cve-id-badge { background: #1565c0; color: #fff; font-size: 0.78rem; font-weight: 800; padding: 0.2rem 0.6rem; border-radius: 5px; font-family: var(--font-mono); }
.cve-name { font-weight: 800; font-size: 1rem; color: var(--text-ink); flex: 1; }
.cve-cvss { font-size: 0.78rem; font-weight: 800; padding: 0.2rem 0.6rem; border-radius: 5px; }
.cve-critical { background: #fef2f2; color: #dc2626; border: 1px solid #fca5a5; }
.cve-high { background: #fff7ed; color: #ea580c; border: 1px solid #fdba74; }
.cve-product { font-size: 0.8rem; color: #64748b; margin-bottom: 0.4rem; }
.cve-desc { font-size: 0.85rem; color: var(--text-dark); margin-bottom: 0.5rem; }
.cve-mitigation { font-size: 0.83rem; color: var(--text-dark); }
.cve-mitigation-code { background: #0f172a; color: #4ade80; border-radius: 8px; padding: 0.6rem 0.8rem; font-family: var(--font-mono); font-size: 0.78rem; margin-top: 0.4rem; white-space: pre-wrap; word-break: break-word; }

/* --- SPACED REPETITION BUTTONS --- */
.sr-row { display: flex; gap: 0.6rem; margin-top: 1rem; padding-top: 0.8rem; border-top: 1px dashed var(--card-border); }
.sr-btn { flex: 1; padding: 0.55rem 0.8rem; border-radius: 8px; font-size: 0.82rem; font-weight: 700; cursor: pointer; transition: all 0.2s; border: 1.5px solid var(--card-border); background: var(--bg-app); color: var(--text-dark); }
.sr-gotit:hover, .sr-active-gotit { background: #dcfce7; border-color: #4ade80; color: #15803d; }
.sr-review:hover, .sr-active-review { background: #fff7ed; border-color: #fb923c; color: #c2410c; }

/* --- VOICE ACTIVE STATE --- */
.btn-voice-active { background: linear-gradient(135deg,#dc2626,#b91c1c) !important; color: #fff !important; animation: pulse-red 1.5s ease-in-out infinite; }
@keyframes pulse-red { 0%,100% { box-shadow: 0 0 0 0 rgba(220,38,38,0.4); } 50% { box-shadow: 0 0 0 8px rgba(220,38,38,0); } }

/* =============================================================
   PART 2 FEATURES — Quizzes, Skill Tree, Custom PDF, Logs, Prism
   ============================================================= */

/* --- END-OF-MODULE QUIZ TRIGGER --- */
.quiz-trigger-strip { margin-top: 2rem; border-top: 2px solid var(--accent-blue); padding-top: 1rem; text-align: center; }
.quiz-trigger-btn { width: 100%; padding: 1rem 1.5rem; background: linear-gradient(135deg,#1565c0,#0d47a1); color: #fff; border: none; border-radius: 12px; font-size: 1rem; font-weight: 800; cursor: pointer; transition: all 0.2s; font-family: var(--font-sans); box-shadow: 0 4px 20px rgba(21,101,192,0.35); }
.quiz-trigger-btn:hover { transform: translateY(-2px); box-shadow: 0 8px 32px rgba(21,101,192,0.5); }

/* --- QUIZ MODAL --- */
.quiz-progress-bar { height: 6px; background: #e2e8f0; border-radius: 999px; margin-bottom: 1.2rem; overflow: hidden; }
.quiz-progress-fill { height: 100%; background: linear-gradient(90deg,#1565c0,#38bdf8); border-radius: 999px; transition: width 0.4s ease; }
.quiz-question { font-size: 1.05rem; font-weight: 700; color: var(--text-ink); margin-bottom: 1.2rem; line-height: 1.5; }
.quiz-options { display: flex; flex-direction: column; gap: 0.6rem; }
.quiz-opt-btn { display: flex; align-items: center; gap: 0.8rem; padding: 0.75rem 1rem; border-radius: 10px; border: 2px solid var(--card-border); background: var(--bg-app); color: var(--text-dark); font-size: 0.92rem; font-weight: 600; cursor: pointer; transition: all 0.18s; text-align: left; }
.quiz-opt-btn:hover:not(:disabled) { border-color: var(--accent-blue); background: rgba(21,101,192,0.06); color: var(--accent-blue); }
.quiz-opt-btn:disabled { cursor: default; }
.quiz-opt-btn.quiz-opt-correct { border-color: #4ade80; background: #dcfce7; color: #15803d; }
.quiz-opt-btn.quiz-opt-wrong { border-color: #f87171; background: #fef2f2; color: #dc2626; }
.quiz-opt-letter { display: inline-flex; align-items: center; justify-content: center; width: 1.6rem; height: 1.6rem; border-radius: 50%; background: var(--accent-blue); color: #fff; font-size: 0.75rem; font-weight: 800; flex-shrink: 0; }
.quiz-feedback { margin-top: 1rem; padding: 0.75rem 1rem; border-radius: 10px; font-size: 0.88rem; font-weight: 600; }
.quiz-feedback.hidden { display: none; }
.quiz-feedback-correct { background: #dcfce7; color: #15803d; border: 1px solid #4ade80; }
.quiz-feedback-wrong { background: #fef2f2; color: #dc2626; border: 1px solid #f87171; }

/* --- EXPANDABLE LOG SNIPPETS --- */
.log-snippet-wrapper { margin: 0.5rem 0; border-radius: 10px; overflow: hidden; border: 1.5px solid var(--card-border); }
.log-snippet-header { display: flex; justify-content: space-between; align-items: center; padding: 0.5rem 0.9rem; background: #1e293b; color: #94a3b8; font-size: 0.82rem; font-family: var(--font-mono); cursor: pointer; }
.log-expand-btn { background: #334155; border: none; color: #38bdf8; padding: 0.2rem 0.6rem; border-radius: 5px; font-size: 0.78rem; font-weight: 700; cursor: pointer; transition: background 0.2s; }
.log-expand-btn:hover { background: #1565c0; color: #fff; }

/* --- VISUAL SKILL TREE --- */
.skill-tree-grid { display: flex; gap: 1rem; overflow-x: auto; padding-bottom: 0.5rem; }
.skill-tree-level { display: flex; flex-direction: column; gap: 0.7rem; min-width: 160px; }
.skill-tree-level-label { font-size: 0.72rem; font-weight: 800; text-transform: uppercase; letter-spacing: 0.08em; color: #94a3b8; padding: 0.2rem 0.5rem; border-bottom: 2px solid var(--card-border); }
.skill-node { padding: 0.9rem 0.75rem; border-radius: 12px; border: 2px solid var(--card-border); text-align: center; transition: transform 0.2s; }
.skill-node:hover { transform: translateY(-2px); }
.skill-done { background: linear-gradient(135deg,#dcfce7,#f0fdf4); border-color: #4ade80; }
.skill-available { background: var(--bg-app); border-color: var(--node-color,#3b82f6); box-shadow: 0 0 0 3px color-mix(in srgb, var(--node-color,#3b82f6) 20%, transparent); }
.skill-locked { background: #f8fafc; border-color: #e2e8f0; opacity: 0.55; filter: grayscale(0.8); }
.skill-node-icon { font-size: 1.6rem; margin-bottom: 0.3rem; }
.skill-node-label { font-size: 0.82rem; font-weight: 800; color: var(--text-ink); line-height: 1.3; margin-bottom: 0.2rem; }
.skill-node-pages { font-size: 0.7rem; color: #64748b; margin-bottom: 0.5rem; }
.skill-node-btn { padding: 0.25rem 0.7rem; border-radius: 6px; border: none; background: var(--node-color,#3b82f6); color: #fff; font-size: 0.75rem; font-weight: 700; cursor: pointer; transition: opacity 0.2s; }
.skill-node-btn:hover { opacity: 0.85; }

/* --- CUSTOM PDF BUILDER --- */
.custpdf-summary { background: var(--bg-app); border-radius: 10px; border: 1.5px solid var(--card-border); padding: 0.9rem 1.1rem; margin-bottom: 0.5rem; }
.custpdf-row { display: flex; justify-content: space-between; align-items: center; padding: 0.3rem 0; font-size: 0.88rem; color: var(--text-dark); border-bottom: 1px solid var(--card-border); }
.custpdf-row:last-child { border-bottom: none; }
.custpdf-total { font-weight: 800; color: var(--accent-blue); padding-top: 0.5rem; }
.custpdf-btn { padding: 0.7rem 1.2rem; border-radius: 10px; border: 2px solid var(--accent-blue); background: var(--accent-blue); color: #fff; font-size: 0.88rem; font-weight: 700; cursor: pointer; transition: all 0.2s; font-family: var(--font-sans); }
.custpdf-btn:hover { background: #0d47a1; border-color: #0d47a1; transform: translateY(-1px); }

/* --- PRISM.JS OVERRIDES (dark theme to match our terminal palette) --- */
code[class*="language-"], pre[class*="language-"] { font-family: var(--font-mono) !important; font-size: 0.85rem !important; border-radius: 8px !important; }
pre[class*="language-"] { margin: 0.5rem 0 !important; padding: 1rem !important; }
:not(pre) > code[class*="language-"] { padding: 0.15em 0.4em; border-radius: 4px; }

/* --- MOBILE BOTTOM NAV (Desktop Hide & Mobile Styling) --- */
.mobile-bottom-nav {
  display: none !important;
}

@media (max-width: 768px) {
  .mobile-bottom-nav {
    display: flex !important;
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    height: 56px;
    background: var(--paper-bg, #f4edd9);
    border-top: 1.5px solid var(--card-border, #e0d7c3);
    z-index: 9999;
    justify-content: space-around;
    align-items: center;
    padding: 0 0.5rem;
    box-shadow: 0 -4px 16px rgba(0,0,0,0.1);
  }
  .mobile-nav-btn {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    background: transparent;
    border: none;
    color: var(--text-dark, #212121);
    font-size: 0.72rem;
    font-weight: 700;
    cursor: pointer;
    gap: 2px;
    padding: 4px 8px;
    border-radius: 6px;
  }
  .mobile-nav-btn:active {
    background: rgba(21, 101, 192, 0.1);
    color: var(--accent-blue, #1565c0);
  }
  .mobile-nav-btn .nav-icon {
    font-size: 1.1rem;
  }
}