/* ============================================================
   DS Master - Complete Design System
   Premium Web3/Glassmorphism Educational Platform
   ============================================================ */

/* ── Google Fonts ── */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700;800;900&family=Tajawal:wght@300;400;500;700;800&family=JetBrains+Mono:wght@400;500;600;700&display=swap');

/* ============================================================
   1. DESIGN TOKENS (CSS Custom Properties)
   ============================================================ */
:root {
  /* ── Dark Theme (Default) ── */
  --bg-primary: #060a13;
  --bg-secondary: #0d1224;
  --bg-tertiary: #131a2e;
  --bg-surface: rgba(13, 18, 36, 0.75);
  --bg-surface-hover: rgba(20, 28, 52, 0.85);
  --bg-glass: rgba(13, 18, 36, 0.55);
  --bg-code: #0d1117;
  --bg-input: rgba(13, 18, 36, 0.6);

  --border-primary: rgba(255, 255, 255, 0.06);
  --border-hover: rgba(255, 255, 255, 0.12);
  --border-glow: rgba(var(--color-primary-rgb), 0.4);
  --border-glass: rgba(255, 255, 255, 0.08);

  --color-primary: #7c6cf0;
  --color-primary-rgb: 124, 108, 240;
  --color-primary-light: #a29bfe;
  --color-primary-dark: #5a4bd1;
  --color-secondary: #00d2d3;
  --color-secondary-rgb: 0, 210, 211;
  --color-secondary-light: #55efc4;
  --color-accent: #fd79a8;
  --color-accent-rgb: 253, 121, 168;
  --color-important: #ff4757;
  --color-important-rgb: 255, 71, 87;
  --color-success: #00b894;
  --color-success-rgb: 0, 184, 148;
  --color-warning: #ffc048;
  --color-warning-rgb: 255, 192, 72;
  --color-error: #ff4757;
  --color-info: #74b9ff;

  --accent-purple: 124, 108, 240;      /* #7c6cf0 */
  --accent-purple-hex: #7c6cf0;
  --accent-teal: 0, 210, 211;         /* #00d2d3 */
  --accent-teal-hex: #00d2d3;
  --accent-blue: 59, 130, 246;         /* #3b82f6 */
  --accent-blue-hex: #3b82f6;
  --accent-green: 16, 185, 129;        /* #10b981 */
  --accent-green-hex: #10b981;
  --accent-orange: 249, 115, 22;       /* #f97316 */
  --accent-orange-hex: #f97316;
  --accent-pink: 236, 72, 153;         /* #ec4899 */
  --accent-pink-hex: #ec4899;

  --text-primary: #e2e8f0;
  --text-secondary: #8892b0;
  --text-muted: #5a6680;
  --text-heading: #f1f5f9;
  --text-inverse: #060a13;
  --text-code: #e6edf3;
  --text-link: var(--color-secondary);

  --gradient-primary: linear-gradient(135deg, var(--color-primary) 0%, var(--color-secondary) 100%);
  --gradient-primary-subtle: linear-gradient(135deg, rgba(var(--color-primary-rgb), 0.15) 0%, rgba(var(--color-secondary-rgb), 0.15) 100%);
  --gradient-secondary: linear-gradient(135deg, var(--color-secondary) 0%, var(--color-secondary-light) 100%);
  --gradient-accent: linear-gradient(135deg, var(--color-accent) 0%, var(--color-primary-light) 100%);
  --gradient-bg: radial-gradient(ellipse at 20% 50%, rgba(var(--color-primary-rgb), 0.08) 0%, transparent 50%),
                 radial-gradient(ellipse at 80% 20%, rgba(var(--color-secondary-rgb), 0.06) 0%, transparent 50%),
                 radial-gradient(ellipse at 50% 80%, rgba(var(--color-accent-rgb), 0.04) 0%, transparent 50%),
                 linear-gradient(180deg, #060a13 0%, #0d1224 100%);
  --gradient-card: linear-gradient(135deg, rgba(var(--color-primary-rgb), 0.06) 0%, rgba(var(--color-secondary-rgb), 0.03) 100%);
  --gradient-sidebar: linear-gradient(180deg, rgba(13,18,36,0.95) 0%, rgba(6,10,19,0.98) 100%);
  --gradient-glow-line: linear-gradient(90deg, transparent, var(--color-primary), var(--color-secondary), transparent);

  --shadow-xs: 0 1px 3px rgba(0,0,0,0.3);
  --shadow-sm: 0 2px 8px rgba(0,0,0,0.35);
  --shadow-md: 0 4px 20px rgba(0,0,0,0.4);
  --shadow-lg: 0 8px 40px rgba(0,0,0,0.5);
  --shadow-xl: 0 16px 64px rgba(0,0,0,0.6);
  --shadow-glow-primary: 0 0 30px rgba(var(--color-primary-rgb), 0.25), 0 0 60px rgba(var(--color-primary-rgb), 0.1);
  --shadow-glow-secondary: 0 0 30px rgba(var(--color-secondary-rgb), 0.25), 0 0 60px rgba(var(--color-secondary-rgb), 0.1);
  --shadow-glow-accent: 0 0 30px rgba(var(--color-accent-rgb), 0.2);
  --shadow-card: 0 4px 24px rgba(0,0,0,0.3), inset 0 1px 0 rgba(255,255,255,0.04);
  --shadow-card-hover: 0 8px 40px rgba(0,0,0,0.4), 0 0 30px rgba(var(--color-primary-rgb), 0.15);

  --blur-glass: 20px;
  --blur-heavy: 40px;

  --radius-xs: 6px;
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-xl: 24px;
  --radius-2xl: 32px;
  --radius-full: 9999px;

  --font-en: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-ar: 'Tajawal', 'Inter', sans-serif;
  --font-code: 'JetBrains Mono', 'Fira Code', 'Consolas', monospace;

  --fs-xs: 0.75rem;
  --fs-sm: 0.875rem;
  --fs-base: 1rem;
  --fs-md: 1.125rem;
  --fs-lg: 1.25rem;
  --fs-xl: 1.5rem;
  --fs-2xl: 1.875rem;
  --fs-3xl: 2.25rem;
  --fs-4xl: 3rem;
  --fs-5xl: 3.75rem;

  --fw-light: 300;
  --fw-normal: 400;
  --fw-medium: 500;
  --fw-semibold: 600;
  --fw-bold: 700;
  --fw-extrabold: 800;

  --lh-tight: 1.25;
  --lh-normal: 1.6;
  --lh-relaxed: 1.8;
  --lh-loose: 2;

  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.25rem;
  --space-6: 1.5rem;
  --space-8: 2rem;
  --space-10: 2.5rem;
  --space-12: 3rem;
  --space-16: 4rem;
  --space-20: 5rem;
  --space-24: 6rem;

  --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-normal: 250ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 400ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-spring: 500ms cubic-bezier(0.34, 1.56, 0.64, 1);

  --sidebar-width: 300px;
  --sidebar-collapsed: 70px;
  --header-height: 70px;
  --z-sidebar: 100;
  --z-header: 110;
  --z-modal: 200;
  --z-toast: 300;
  --z-particles: -1;

  --scrollbar-w: 6px;
  --scrollbar-track: rgba(255,255,255,0.03);
  --scrollbar-thumb: rgba(var(--color-primary-rgb), 0.3);
}

/* ── Light Theme ── */
[data-theme="light"] {
  --bg-primary: #f4f6fb;
  --bg-secondary: #ffffff;
  --bg-tertiary: #eef1f8;
  --bg-surface: rgba(255, 255, 255, 0.8);
  --bg-surface-hover: rgba(255, 255, 255, 0.95);
  --bg-glass: rgba(255, 255, 255, 0.6);
  --bg-code: #f6f8fa;
  --bg-input: rgba(255, 255, 255, 0.7);

  --border-primary: rgba(0, 0, 0, 0.08);
  --border-hover: rgba(0, 0, 0, 0.15);
  --border-glow: rgba(var(--color-primary-rgb), 0.3);
  --border-glass: rgba(0, 0, 0, 0.06);

  --color-primary: #5f3dc4;
  --color-primary-rgb: 95, 61, 196;
  --color-primary-light: #7950f2;
  --color-primary-dark: #4c2ca0;
  --color-secondary: #0891b2;
  --color-secondary-rgb: 8, 145, 178;
  --color-secondary-light: #06b6d4;

  --text-primary: #1e293b;
  --text-secondary: #475569;
  --text-muted: #94a3b8;
  --text-heading: #0f172a;
  --text-inverse: #f1f5f9;
  --text-code: #1f2937;

  --gradient-bg: radial-gradient(ellipse at 20% 50%, rgba(var(--color-primary-rgb), 0.06) 0%, transparent 50%),
                 radial-gradient(ellipse at 80% 20%, rgba(var(--color-secondary-rgb), 0.05) 0%, transparent 50%),
                 linear-gradient(180deg, #f4f6fb 0%, #eef1f8 100%);
  --gradient-sidebar: linear-gradient(180deg, rgba(255,255,255,0.95) 0%, rgba(244,246,251,0.98) 100%);

  --shadow-xs: 0 1px 3px rgba(0,0,0,0.06);
  --shadow-sm: 0 2px 8px rgba(0,0,0,0.08);
  --shadow-md: 0 4px 20px rgba(0,0,0,0.1);
  --shadow-lg: 0 8px 40px rgba(0,0,0,0.12);
  --shadow-xl: 0 16px 64px rgba(0,0,0,0.15);
  --shadow-glow-primary: 0 0 30px rgba(var(--color-primary-rgb), 0.15), 0 0 60px rgba(var(--color-primary-rgb), 0.05);
  --shadow-glow-secondary: 0 0 30px rgba(var(--color-secondary-rgb), 0.15);
  --shadow-card: 0 4px 24px rgba(0,0,0,0.06), inset 0 1px 0 rgba(255,255,255,0.5);
  --shadow-card-hover: 0 8px 40px rgba(0,0,0,0.1), 0 0 30px rgba(var(--color-primary-rgb), 0.08);

  --scrollbar-track: rgba(0,0,0,0.03);
  --scrollbar-thumb: rgba(var(--color-primary-rgb), 0.25);
}

/* ── Pitch Black Theme (Additional) ── */
[data-theme="black"] {
  --bg-primary: #000000;
  --bg-secondary: #050505;
  --bg-tertiary: #0b0b0c;
  --bg-surface: rgba(8, 8, 8, 0.88);
  --bg-surface-hover: rgba(16, 16, 16, 0.95);
  --bg-glass: rgba(0, 0, 0, 0.8);
  --bg-code: #000000;
  --bg-input: rgba(6, 6, 6, 0.9);

  --border-primary: rgba(255, 255, 255, 0.09);
  --border-hover: rgba(255, 255, 255, 0.16);
  --border-glow: rgba(var(--color-primary-rgb), 0.5);
  --border-glass: rgba(255, 255, 255, 0.11);

  --color-primary: #7c6cf0;
  --color-primary-rgb: 124, 108, 240;
  --color-primary-light: #a29bfe;
  --color-primary-dark: #5a4bd1;
  --color-secondary: #00d2d3;
  --color-secondary-rgb: 0, 210, 211;
  --color-secondary-light: #55efc4;

  --text-primary: #f4f4f5;
  --text-secondary: #a1a1aa;
  --text-muted: #52525b;
  --text-heading: #fafafa;
  --text-inverse: #000000;

  --gradient-bg: radial-gradient(ellipse at 20% 50%, rgba(var(--color-primary-rgb), 0.15) 0%, transparent 50%),
                 radial-gradient(ellipse at 80% 20%, rgba(var(--color-secondary-rgb), 0.1) 0%, transparent 50%),
                 linear-gradient(180deg, #000000 0%, #050505 100%);
  --gradient-sidebar: linear-gradient(180deg, rgba(5,5,5,0.99) 0%, rgba(0,0,0,1) 100%);

  --shadow-xs: 0 1px 3px rgba(0,0,0,0.6);
  --shadow-sm: 0 2px 8px rgba(0,0,0,0.7);
  --shadow-md: 0 4px 20px rgba(0,0,0,0.8);
  --shadow-lg: 0 8px 40px rgba(0,0,0,0.9);
  --shadow-xl: 0 16px 64px rgba(0,0,0,0.95);
  --shadow-card: 0 4px 24px rgba(0,0,0,0.7), inset 0 1px 0 rgba(255,255,255,0.06);
  --shadow-card-hover: 0 8px 40px rgba(0,0,0,0.9), 0 0 30px rgba(var(--color-primary-rgb), 0.25);

  --scrollbar-track: rgba(0,0,0,0.3);
  --scrollbar-thumb: rgba(255,255,255,0.15);
}

[data-accent="purple"] { 
  --color-primary-rgb: var(--accent-purple); 
  --color-primary: var(--accent-purple-hex);
}
[data-accent="teal"] { 
  --color-primary-rgb: var(--accent-teal); 
  --color-primary: var(--accent-teal-hex);
}
[data-accent="blue"] { 
  --color-primary-rgb: var(--accent-blue); 
  --color-primary: var(--accent-blue-hex);
}
[data-accent="green"] { 
  --color-primary-rgb: var(--accent-green); 
  --color-primary: var(--accent-green-hex);
}
[data-accent="orange"] { 
  --color-primary-rgb: var(--accent-orange); 
  --color-primary: var(--accent-orange-hex);
}
[data-accent="pink"] { 
  --color-primary-rgb: var(--accent-pink); 
  --color-primary: var(--accent-pink-hex);
}

/* ============================================================
   2. BASE / RESET
   ============================================================ */
*, *::before, *::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font-en);
  background: var(--gradient-bg);
  background-attachment: fixed;
  color: var(--text-primary);
  line-height: var(--lh-normal);
  min-height: 100vh;
  overflow-x: hidden;
  transition: background var(--transition-slow), color var(--transition-slow);
}

body[dir="rtl"] {
  font-family: var(--font-ar);
}

/* Scrollbar */
::-webkit-scrollbar { width: var(--scrollbar-w); height: var(--scrollbar-w); }
::-webkit-scrollbar-track { background: var(--scrollbar-track); }
::-webkit-scrollbar-thumb {
  background: var(--scrollbar-thumb);
  border-radius: var(--radius-full);
}
::-webkit-scrollbar-thumb:hover { background: var(--color-primary); }

::selection {
  background: rgba(var(--color-primary-rgb), 0.3);
  color: var(--text-heading);
}

a { color: var(--text-link); text-decoration: none; transition: color var(--transition-fast); }
a:hover { color: var(--color-primary-light); }

img { max-width: 100%; height: auto; }
button { cursor: pointer; font-family: inherit; }
code { font-family: var(--font-code); }

/* ============================================================
   3. PARTICLE CANVAS (Background)
   ============================================================ */
#particles-canvas {
  position: fixed;
  top: 0; left: 0;
  width: 100%; height: 100%;
  z-index: var(--z-particles);
  pointer-events: none;
}

/* ============================================================
   4. LAYOUT
   ============================================================ */
.app-wrapper {
  display: block;
  min-height: 100vh;
  width: 100%;
}

/* ── Header / Topbar ── */
.header {
  position: fixed;
  top: 0;
  left: var(--sidebar-width);
  right: 0;
  height: var(--header-height);
  background: var(--bg-glass);
  backdrop-filter: blur(var(--blur-glass));
  -webkit-backdrop-filter: blur(var(--blur-glass));
  border-bottom: 1px solid var(--border-glass);
  z-index: var(--z-header);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 var(--space-8);
  transition: left var(--transition-normal), background var(--transition-slow);
}

body[dir="rtl"] .header {
  left: 0;
  right: var(--sidebar-width);
}

.header-left {
  display: flex;
  align-items: center;
  gap: var(--space-4);
}

.header-right {
  display: flex;
  align-items: center;
  gap: var(--space-3);
}

/* ── Lang Toggle ── */
.lang-toggle {
  display: flex;
  background: var(--bg-input);
  border-radius: var(--radius-sm);
  padding: 2px;
  border: 1px solid var(--border-glass);
}

.lang-option {
  background: transparent;
  border: none;
  color: var(--text-secondary);
  padding: var(--space-1) var(--space-3);
  font-size: var(--fs-xs);
  font-weight: var(--fw-medium);
  border-radius: calc(var(--radius-sm) - 2px);
  transition: all var(--transition-fast);
}

.lang-option:hover {
  color: var(--text-primary);
}

.lang-option.active {
  background: var(--bg-surface);
  color: var(--color-primary-light);
  box-shadow: var(--shadow-xs);
}

/* ── Theme Menu ── */
.theme-menu-container {
  position: relative;
  display: flex;
  align-items: center;
}

.theme-menu-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: var(--radius-sm);
  background: var(--bg-surface);
  border: 1px solid var(--border-glass);
  color: var(--text-primary);
  font-size: 1.1rem;
  transition: all var(--transition-fast);
}

.theme-menu-btn:hover {
  background: var(--bg-surface-hover);
  border-color: rgba(var(--color-primary-rgb), 0.3);
  box-shadow: 0 0 10px rgba(var(--color-primary-rgb), 0.1);
}

.theme-menu-dropdown {
  position: absolute;
  top: 120%;
  right: 0;
  width: 280px;
  background: var(--bg-surface);
  backdrop-filter: blur(var(--blur-heavy));
  -webkit-backdrop-filter: blur(var(--blur-heavy));
  border: 1px solid var(--border-glass);
  border-radius: var(--radius-md);
  padding: var(--space-4);
  box-shadow: var(--shadow-lg);
  opacity: 0;
  visibility: hidden;
  transform: translateY(10px) scale(0.95);
  transition: all var(--transition-fast);
  z-index: var(--z-modal);
  pointer-events: none;
}

body[dir="rtl"] .theme-menu-dropdown {
  right: auto;
  left: 0;
}

.theme-menu-dropdown.active {
  opacity: 1;
  visibility: visible;
  transform: translateY(0) scale(1);
  pointer-events: auto;
}

.theme-dropdown-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: var(--space-4);
  padding-bottom: var(--space-2);
  border-bottom: 1px solid var(--border-primary);
}

.theme-dropdown-title {
  font-size: var(--fs-sm);
  font-weight: var(--fw-semibold);
  color: var(--text-secondary);
}

.theme-modes-row {
  display: flex;
  gap: var(--space-2);
  margin-bottom: var(--space-4);
}

.theme-mode-btn {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-2);
  background: var(--bg-input);
  border: 1px solid var(--border-glass);
  border-radius: var(--radius-sm);
  color: var(--text-secondary);
  transition: all var(--transition-fast);
}

.theme-mode-btn:hover {
  background: var(--bg-surface-hover);
  color: var(--text-primary);
  border-color: var(--border-hover);
}

.theme-mode-btn.active {
  background: var(--gradient-primary);
  color: #fff;
  border-color: transparent;
  box-shadow: var(--shadow-glow-primary);
}

.mode-icon {
  font-size: 1.2rem;
}

.mode-label {
  font-size: var(--fs-xs);
  font-weight: var(--fw-medium);
}

.theme-accents-grid {
  display: grid;
  grid-template-columns: repeat(6, 1fr);
  gap: var(--space-2);
  justify-items: center;
}

.theme-accent-dot {
  width: 24px;
  height: 24px;
  border-radius: 50%;
  border: 2px solid transparent;
  cursor: pointer;
  transition: transform var(--transition-fast), box-shadow var(--transition-fast);
}

.theme-accent-dot:hover {
  transform: scale(1.1);
}

.theme-accent-dot.active {
  transform: scale(1.2);
  border: 2px solid #fff;
  box-shadow: 0 0 0 2px var(--bg-surface), 0 0 10px currentColor;
}

/* Animations Toggle */
.theme-animation-toggle {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-top: var(--space-4);
  padding-top: var(--space-3);
  border-top: 1px solid var(--border-primary);
}

.animation-label {
  font-size: var(--fs-xs);
  font-weight: var(--fw-semibold);
  color: var(--text-secondary);
}

/* Switch styling */
.switch {
  position: relative;
  display: inline-block;
  width: 36px;
  height: 20px;
}
.switch input { 
  opacity: 0;
  width: 0;
  height: 0;
}
.slider {
  position: absolute;
  cursor: pointer;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-color: var(--bg-surface-hover);
  transition: .4s;
}
.slider:before {
  position: absolute;
  content: "";
  height: 14px;
  width: 14px;
  left: 3px;
  bottom: 3px;
  background-color: white;
  transition: .4s;
}
input:checked + .slider {
  background: var(--gradient-primary);
}
input:checked + .slider:before {
  transform: translateX(16px);
}
.slider.round {
  border-radius: 34px;
}
.slider.round:before {
  border-radius: 50%;
}

.breadcrumb {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  font-size: var(--fs-sm);
  color: var(--text-secondary);
}

.breadcrumb-sep { opacity: 0.4; }
.breadcrumb-current { color: var(--text-primary); font-weight: var(--fw-medium); }

.menu-toggle {
  display: flex;
  background: none;
  border: none;
  color: var(--text-primary);
  font-size: 1.5rem;
  padding: var(--space-2);
  border-radius: var(--radius-sm);
  transition: background var(--transition-fast);
}
.menu-toggle:hover { background: var(--bg-surface); }

/* ── Sidebar ── */
.sidebar {
  position: fixed;
  top: 0;
  left: 0;
  width: var(--sidebar-width);
  height: 100vh;
  background: var(--gradient-sidebar);
  backdrop-filter: blur(var(--blur-heavy));
  -webkit-backdrop-filter: blur(var(--blur-heavy));
  border-right: 1px solid var(--border-glass);
  z-index: var(--z-sidebar);
  display: flex;
  flex-direction: column;
  transition: transform var(--transition-normal), background var(--transition-slow);
  overflow: hidden;
}

body[dir="rtl"] .sidebar {
  left: auto;
  right: 0;
  border-right: none;
  border-left: 1px solid var(--border-glass);
}

.sidebar-header {
  padding: var(--space-6) var(--space-6) var(--space-4);
  border-bottom: 1px solid var(--border-primary);
  flex-shrink: 0;
}

.sidebar-logo {
  display: flex;
  align-items: center;
  gap: var(--space-3);
}

.logo-icon {
  width: 44px;
  height: 44px;
  background: var(--gradient-primary);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.4rem;
  box-shadow: var(--shadow-glow-primary);
  position: relative;
  overflow: hidden;
}

.logo-icon::after {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, rgba(255,255,255,0.2) 0%, transparent 50%);
  border-radius: inherit;
}

.logo-text {
  display: flex;
  flex-direction: column;
}

.logo-title {
  font-size: var(--fs-lg);
  font-weight: var(--fw-bold);
  background: var(--gradient-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  line-height: var(--lh-tight);
}

.logo-subtitle {
  font-size: var(--fs-xs);
  color: var(--text-muted);
  font-weight: var(--fw-normal);
}

/* Sidebar subject selector */
.subject-selector {
  padding: var(--space-4) var(--space-6);
  border-bottom: 1px solid var(--border-primary);
  flex-shrink: 0;
}

.subject-badge {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-2) var(--space-3);
  background: var(--gradient-primary-subtle);
  border: 1px solid rgba(var(--color-primary-rgb), 0.2);
  border-radius: var(--radius-sm);
  font-size: var(--fs-sm);
  color: var(--color-primary-light);
  font-weight: var(--fw-medium);
}

.subject-badge-icon { font-size: 1rem; }

/* Sidebar nav */
.sidebar-nav {
  flex: 1;
  overflow-y: auto;
  padding: var(--space-4) var(--space-3);
}

.nav-section-title {
  font-size: var(--fs-xs);
  font-weight: var(--fw-semibold);
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  padding: var(--space-2) var(--space-3);
  margin-bottom: var(--space-1);
}

.nav-item {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: var(--space-3) var(--space-3);
  border-radius: var(--radius-sm);
  color: var(--text-secondary);
  font-size: var(--fs-sm);
  font-weight: var(--fw-medium);
  cursor: pointer;
  transition: all var(--transition-fast);
  position: relative;
  margin-bottom: 2px;
  border: 1px solid transparent;
  user-select: none;
}

.nav-item:hover {
  background: var(--bg-surface);
  color: var(--text-primary);
  border-color: var(--border-primary);
}

.nav-item.active {
  background: var(--gradient-primary-subtle);
  color: var(--color-primary-light);
  border-color: rgba(var(--color-primary-rgb), 0.2);
  box-shadow: 0 0 20px rgba(var(--color-primary-rgb), 0.08);
}

.nav-item.active::before {
  content: '';
  position: absolute;
  left: 0;
  top: 50%;
  transform: translateY(-50%);
  width: 3px;
  height: 60%;
  background: var(--gradient-primary);
  border-radius: 0 var(--radius-full) var(--radius-full) 0;
}

body[dir="rtl"] .nav-item.active::before {
  left: auto;
  right: 0;
  border-radius: var(--radius-full) 0 0 var(--radius-full);
}

.nav-item-icon {
  width: 32px;
  height: 32px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-xs);
  background: var(--bg-surface);
  font-size: 0.9rem;
  flex-shrink: 0;
  transition: all var(--transition-fast);
}

.nav-item.active .nav-item-icon {
  background: rgba(var(--color-primary-rgb), 0.15);
}

.nav-item-text {
  flex: 1;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.nav-item-badge {
  font-size: var(--fs-xs);
  padding: 1px 6px;
  border-radius: var(--radius-full);
  background: rgba(var(--color-primary-rgb), 0.15);
  color: var(--color-primary-light);
  font-weight: var(--fw-semibold);
}

.nav-item-badge.completed {
  background: rgba(var(--color-success-rgb), 0.15);
  color: var(--color-success);
}

/* Sidebar footer */
.sidebar-footer {
  padding: var(--space-4) var(--space-6);
  border-top: 1px solid var(--border-primary);
  flex-shrink: 0;
}

.sidebar-progress {
  margin-bottom: var(--space-3);
}

.progress-label {
  display: flex;
  justify-content: space-between;
  font-size: var(--fs-xs);
  color: var(--text-muted);
  margin-bottom: var(--space-2);
}

.progress-bar {
  width: 100%;
  height: 6px;
  background: var(--bg-surface);
  border-radius: var(--radius-full);
  overflow: hidden;
}

.progress-fill {
  height: 100%;
  background: var(--gradient-primary);
  border-radius: var(--radius-full);
  transition: width var(--transition-slow);
  position: relative;
}

.progress-fill::after {
  content: '';
  position: absolute;
  right: 0;
  top: 0;
  width: 20px;
  height: 100%;
  background: linear-gradient(90deg, transparent, rgba(255,255,255,0.4));
  animation: progressShine 2s ease-in-out infinite;
}

/* Comprehensive Exam button */
.exam-btn {
  width: 100%;
  padding: var(--space-3) var(--space-4);
  background: var(--gradient-accent);
  border: none;
  border-radius: var(--radius-sm);
  color: white;
  font-weight: var(--fw-semibold);
  font-size: var(--fs-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  transition: all var(--transition-normal);
  box-shadow: 0 4px 15px rgba(var(--color-accent-rgb), 0.3);
}

.exam-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 25px rgba(var(--color-accent-rgb), 0.4);
}

/* ── Main Content ── */
.main-content {
  flex: 1;
  min-width: 0;
  margin-left: var(--sidebar-width);
  margin-top: var(--header-height);
  padding: var(--space-8);
  min-height: calc(100vh - var(--header-height));
  transition: margin var(--transition-normal);
}

body[dir="rtl"] .main-content {
  margin-left: 0;
  margin-right: var(--sidebar-width);
}

.content-wrapper {
  width: 80%;
  max-width: 1400px;
  margin: 0 auto;
  animation: fadeInUp 0.5s ease-out;
}

@media (max-width: 1024px) {
  .content-wrapper {
    width: 95%;
  }
}

/* ============================================================
   5. BUTTONS
   ============================================================ */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  padding: var(--space-2) var(--space-5);
  border: 1px solid transparent;
  border-radius: var(--radius-sm);
  font-size: var(--fs-sm);
  font-weight: var(--fw-semibold);
  cursor: pointer;
  transition: all var(--transition-normal);
  white-space: nowrap;
  text-decoration: none;
  position: relative;
  overflow: hidden;
}

.btn::before {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, rgba(255,255,255,0.1) 0%, transparent 50%);
  opacity: 0;
  transition: opacity var(--transition-fast);
}

.btn:hover::before { opacity: 1; }

.btn-primary {
  background: var(--gradient-primary);
  color: white;
  box-shadow: 0 4px 15px rgba(var(--color-primary-rgb), 0.3);
}
.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 25px rgba(var(--color-primary-rgb), 0.4);
}

.btn-secondary {
  background: var(--bg-surface);
  color: var(--text-primary);
  border-color: var(--border-primary);
  backdrop-filter: blur(10px);
}
.btn-secondary:hover {
  background: var(--bg-surface-hover);
  border-color: var(--border-hover);
}

.btn-ghost {
  background: transparent;
  color: var(--text-secondary);
}
.btn-ghost:hover {
  background: var(--bg-surface);
  color: var(--text-primary);
}

.btn-icon {
  width: 40px;
  height: 40px;
  padding: 0;
  border-radius: var(--radius-sm);
  background: var(--bg-surface);
  border: 1px solid var(--border-primary);
  color: var(--text-secondary);
  font-size: 1.1rem;
  backdrop-filter: blur(10px);
  transition: all var(--transition-normal);
}
.btn-icon:hover {
  color: var(--text-primary);
  border-color: var(--border-hover);
  background: var(--bg-surface-hover);
  transform: translateY(-1px);
}

.btn-quiz {
  background: var(--gradient-secondary);
  color: var(--text-inverse);
  font-weight: var(--fw-bold);
  padding: var(--space-3) var(--space-8);
  border-radius: var(--radius-lg);
  font-size: var(--fs-md);
  box-shadow: 0 4px 20px rgba(var(--color-secondary-rgb), 0.35);
}
.btn-quiz:hover {
  transform: translateY(-3px) scale(1.02);
  box-shadow: 0 8px 35px rgba(var(--color-secondary-rgb), 0.45);
}

/* Language Toggle Button */
.lang-toggle {
  display: flex;
  align-items: center;
  background: var(--bg-surface);
  border: 1px solid var(--border-primary);
  border-radius: var(--radius-full);
  padding: 3px;
  gap: 2px;
  backdrop-filter: blur(10px);
}

.lang-option {
  padding: var(--space-1) var(--space-3);
  border-radius: var(--radius-full);
  border: none;
  background: transparent;
  color: var(--text-muted);
  font-size: var(--fs-xs);
  font-weight: var(--fw-semibold);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.lang-option.active {
  background: var(--gradient-primary);
  color: white;
  box-shadow: 0 2px 8px rgba(var(--color-primary-rgb), 0.3);
}

/* Theme Toggle */
.theme-toggle {
  position: relative;
  width: 52px;
  height: 28px;
  border-radius: var(--radius-full);
  background: var(--bg-surface);
  border: 1px solid var(--border-primary);
  cursor: pointer;
  transition: all var(--transition-normal);
  overflow: hidden;
}

.theme-toggle-thumb {
  position: absolute;
  top: 3px;
  left: 3px;
  width: 20px;
  height: 20px;
  border-radius: 50%;
  background: var(--gradient-primary);
  transition: all var(--transition-spring);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.7rem;
  box-shadow: 0 2px 6px rgba(0,0,0,0.3);
}

[data-theme="light"] .theme-toggle-thumb {
  left: 27px;
  background: var(--gradient-secondary);
}

/* ============================================================
   6. CARDS
   ============================================================ */
.card {
  background: var(--bg-surface);
  backdrop-filter: blur(var(--blur-glass));
  -webkit-backdrop-filter: blur(var(--blur-glass));
  border: 1px solid var(--border-glass);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  box-shadow: var(--shadow-card);
  transition: all var(--transition-normal);
  position: relative;
  overflow: hidden;
}

.card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 1px;
  background: var(--gradient-glow-line);
  opacity: 0;
  transition: opacity var(--transition-normal);
}

.card:hover::before { opacity: 1; }

.card:hover {
  border-color: var(--border-hover);
  box-shadow: var(--shadow-card-hover);
  transform: translateY(-2px);
}

.card-3d {
  perspective: 1000px;
  transform-style: preserve-3d;
}

.card-3d:hover {
  transform: translateY(-4px) rotateX(2deg) rotateY(-2deg);
}

/* Lecture card (home page) */
.lecture-card {
  display: flex;
  gap: var(--space-5);
  align-items: flex-start;
  cursor: pointer;
}

.lecture-card-num {
  width: 56px;
  height: 56px;
  background: var(--gradient-primary-subtle);
  border: 1px solid rgba(var(--color-primary-rgb), 0.15);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: var(--fs-xl);
  font-weight: var(--fw-extrabold);
  color: var(--color-primary-light);
  flex-shrink: 0;
  transition: all var(--transition-normal);
}

.lecture-card:hover .lecture-card-num {
  background: var(--gradient-primary);
  color: white;
  box-shadow: var(--shadow-glow-primary);
  transform: scale(1.05) rotate(-3deg);
}

.lecture-card-content { flex: 1; }

.lecture-card-title {
  font-size: var(--fs-lg);
  font-weight: var(--fw-bold);
  color: var(--text-heading);
  margin-bottom: var(--space-1);
  line-height: var(--lh-tight);
}

.lecture-card-desc {
  font-size: var(--fs-sm);
  color: var(--text-secondary);
  margin-bottom: var(--space-3);
}

.lecture-card-meta {
  display: flex;
  align-items: center;
  gap: var(--space-4);
  font-size: var(--fs-xs);
  color: var(--text-muted);
}

.lecture-card-tag {
  padding: 2px 8px;
  border-radius: var(--radius-full);
  background: rgba(var(--color-secondary-rgb), 0.1);
  color: var(--color-secondary);
  font-weight: var(--fw-medium);
}

/* ============================================================
   7. LECTURE CONTENT STYLES
   ============================================================ */
.lecture-header {
  margin-bottom: var(--space-10);
  text-align: center;
  position: relative;
}

.lecture-num-badge {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-1) var(--space-4);
  background: var(--gradient-primary-subtle);
  border: 1px solid rgba(var(--color-primary-rgb), 0.2);
  border-radius: var(--radius-full);
  font-size: var(--fs-sm);
  color: var(--color-primary-light);
  font-weight: var(--fw-semibold);
  margin-bottom: var(--space-4);
}

.lecture-title {
  font-size: var(--fs-3xl);
  font-weight: var(--fw-extrabold);
  color: var(--text-heading);
  margin-bottom: var(--space-3);
  line-height: var(--lh-tight);
  background: var(--gradient-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.lecture-subtitle {
  font-size: var(--fs-md);
  color: var(--text-secondary);
}

/* Section inside lecture */
.section {
  margin-bottom: var(--space-10);
  animation: fadeInUp 0.5s ease-out backwards;
}

.section:nth-child(1) { animation-delay: 0.1s; }
.section:nth-child(2) { animation-delay: 0.2s; }
.section:nth-child(3) { animation-delay: 0.3s; }
.section:nth-child(4) { animation-delay: 0.4s; }
.section:nth-child(5) { animation-delay: 0.5s; }

.section-title {
  font-size: var(--fs-xl);
  font-weight: var(--fw-bold);
  color: var(--text-heading);
  margin-bottom: var(--space-5);
  padding-bottom: var(--space-3);
  border-bottom: 2px solid var(--border-primary);
  display: flex;
  align-items: center;
  gap: var(--space-3);
}

.section-title-icon {
  width: 36px;
  height: 36px;
  background: var(--gradient-primary-subtle);
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1rem;
  flex-shrink: 0;
}

body[dir="rtl"] .section-title {
  border-right: 4px solid var(--color-primary);
  border-bottom: none;
  padding-right: var(--space-4);
  padding-bottom: 0;
}

.content-block {
  background: var(--bg-surface);
  backdrop-filter: blur(var(--blur-glass));
  border: 1px solid var(--border-glass);
  border-radius: var(--radius-md);
  padding: var(--space-5);
  margin-bottom: var(--space-4);
  line-height: var(--lh-relaxed);
  font-size: var(--fs-base);
}

.content-block p {
  margin-bottom: var(--space-3);
}

.content-block p:last-child {
  margin-bottom: 0;
}

/* Important terms (red highlight) */
.term-important {
  color: var(--color-important);
  font-weight: var(--fw-bold);
  position: relative;
}

.term-important::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 0;
  right: 0;
  height: 2px;
  background: rgba(var(--color-important-rgb), 0.4);
  border-radius: var(--radius-full);
}

/* English terms inside Arabic text */
.term-en {
  font-family: var(--font-code);
  color: var(--color-secondary);
  direction: ltr;
  display: inline;
  font-size: 0.95em;
  background: rgba(var(--color-secondary-rgb), 0.08);
  padding: 1px 6px;
  border-radius: var(--radius-xs);
}

/* Key formula/concept highlight */
.formula-highlight {
  display: block;
  text-align: center;
  padding: var(--space-4) var(--space-6);
  margin: var(--space-4) 0;
  background: var(--gradient-primary-subtle);
  border: 1px solid rgba(var(--color-primary-rgb), 0.2);
  border-radius: var(--radius-md);
  font-size: var(--fs-xl);
  font-weight: var(--fw-bold);
  color: var(--color-primary-light);
  font-family: var(--font-code);
}

/* Tip box */
.tip-box {
  padding: var(--space-4) var(--space-5);
  border-radius: var(--radius-md);
  margin: var(--space-4) 0;
  display: flex;
  align-items: flex-start;
  gap: var(--space-3);
  font-size: var(--fs-sm);
}

.tip-box-icon {
  font-size: 1.3rem;
  flex-shrink: 0;
  margin-top: 2px;
}

.tip-box.important {
  background: rgba(var(--color-important-rgb), 0.08);
  border: 1px solid rgba(var(--color-important-rgb), 0.2);
  color: #ffa0a8;
}

[data-theme="light"] .tip-box.important { color: var(--color-important); }

.tip-box.info {
  background: rgba(var(--color-secondary-rgb), 0.08);
  border: 1px solid rgba(var(--color-secondary-rgb), 0.2);
  color: var(--color-secondary-light);
}

.tip-box.success {
  background: rgba(var(--color-success-rgb), 0.08);
  border: 1px solid rgba(var(--color-success-rgb), 0.2);
  color: var(--color-success);
}

/* ============================================================
   8. CODE BLOCKS
   ============================================================ */
.code-block {
  background: var(--bg-code);
  border: 1px solid var(--border-primary);
  border-radius: var(--radius-md);
  margin: var(--space-4) 0;
  overflow: hidden;
  position: relative;
}

.code-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-2) var(--space-4);
  background: rgba(255,255,255,0.03);
  border-bottom: 1px solid var(--border-primary);
  font-size: var(--fs-xs);
  color: var(--text-muted);
}

.code-lang-badge {
  padding: 2px 8px;
  background: rgba(var(--color-primary-rgb), 0.15);
  border-radius: var(--radius-xs);
  color: var(--color-primary-light);
  font-weight: var(--fw-semibold);
}

.code-body {
  padding: var(--space-4) var(--space-5);
  overflow-x: auto;
  font-family: var(--font-code);
  font-size: var(--fs-sm);
  line-height: var(--lh-relaxed);
  color: var(--text-code);
  direction: ltr;
  text-align: left;
  white-space: pre;
  tab-size: 4;
}

/* Syntax highlighting */
.hl-keyword { color: #ff7b72; font-weight: var(--fw-medium); }
.hl-type { color: #79c0ff; }
.hl-string { color: #a5d6ff; }
.hl-number { color: #d2a8ff; }
.hl-comment { color: #8b949e; font-style: italic; }
.hl-function { color: #d2a8ff; }
.hl-operator { color: #ff7b72; }
.hl-class { color: #ffa657; }

/* Complexity result box */
.complexity-result {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-3);
  padding: var(--space-3) var(--space-5);
  margin: var(--space-4) 0;
  background: rgba(var(--color-secondary-rgb), 0.08);
  border: 1px solid rgba(var(--color-secondary-rgb), 0.25);
  border-radius: var(--radius-md);
  font-family: var(--font-code);
  font-size: var(--fs-lg);
  font-weight: var(--fw-bold);
  color: var(--color-secondary);
}

/* ============================================================
   9. DIAGRAM / VISUALIZATION BOXES
   ============================================================ */
.diagram-container {
  background: var(--bg-surface);
  border: 1px dashed rgba(var(--color-primary-rgb), 0.3);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  margin: var(--space-6) 0;
  text-align: center;
  position: relative;
  overflow: hidden;
}

.diagram-container::before {
  content: '';
  position: absolute;
  inset: 0;
  background: var(--gradient-card);
  pointer-events: none;
}

.diagram-title {
  font-size: var(--fs-md);
  font-weight: var(--fw-bold);
  color: var(--color-primary-light);
  margin-bottom: var(--space-4);
  position: relative;
}

.diagram-desc {
  font-size: var(--fs-sm);
  color: var(--text-muted);
  margin-bottom: var(--space-5);
  position: relative;
}

/* Interactive visualization area */
.viz-area {
  min-height: 200px;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-wrap: wrap;
  gap: var(--space-3);
  position: relative;
}

.viz-controls {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  margin-top: var(--space-4);
  position: relative;
}

.viz-controls input {
  padding: var(--space-2) var(--space-3);
  border: 1px solid var(--border-primary);
  border-radius: var(--radius-sm);
  background: var(--bg-input);
  color: var(--text-primary);
  font-family: var(--font-code);
  width: 80px;
  text-align: center;
}

/* Array cells */
.array-cell {
  width: 52px;
  height: 52px;
  background: var(--bg-tertiary);
  border: 2px solid rgba(var(--color-primary-rgb), 0.4);
  border-radius: var(--radius-xs);
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-code);
  font-weight: var(--fw-bold);
  font-size: var(--fs-md);
  color: var(--text-heading);
  position: relative;
  transition: all var(--transition-normal);
}

.array-cell:hover {
  border-color: var(--color-primary);
  box-shadow: var(--shadow-glow-primary);
  transform: translateY(-3px);
}

.array-cell .cell-index {
  position: absolute;
  bottom: -22px;
  font-size: var(--fs-xs);
  color: var(--text-muted);
  font-weight: var(--fw-normal);
}

/* Stack visualization */
.stack-viz {
  display: inline-flex;
  flex-direction: column-reverse;
  border-bottom: 3px solid var(--color-primary);
  border-left: 3px solid var(--color-primary);
  border-right: 3px solid var(--color-primary);
  border-radius: 0 0 var(--radius-sm) var(--radius-sm);
  padding: var(--space-2);
  min-width: 120px;
  position: relative;
}

.stack-item {
  padding: var(--space-2) var(--space-4);
  background: var(--bg-tertiary);
  border: 1px solid rgba(var(--color-primary-rgb), 0.3);
  border-radius: var(--radius-xs);
  margin-top: var(--space-1);
  font-family: var(--font-code);
  font-weight: var(--fw-bold);
  color: var(--text-heading);
  text-align: center;
  transition: all var(--transition-normal);
  animation: slideInFromTop 0.3s ease-out;
}

.stack-top-indicator {
  position: absolute;
  top: -30px;
  left: 50%;
  transform: translateX(-50%);
  color: var(--color-important);
  font-weight: var(--fw-bold);
  font-size: var(--fs-sm);
  white-space: nowrap;
}

/* Queue visualization */
.queue-viz {
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

.queue-items {
  display: flex;
  border-top: 3px solid var(--color-secondary);
  border-bottom: 3px solid var(--color-secondary);
  padding: var(--space-2);
  gap: var(--space-1);
  min-width: 60px;
}

.queue-item {
  width: 48px;
  height: 48px;
  background: var(--bg-tertiary);
  border: 1px solid rgba(var(--color-secondary-rgb), 0.3);
  border-radius: var(--radius-xs);
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-code);
  font-weight: var(--fw-bold);
  color: var(--text-heading);
  animation: slideInFromLeft 0.3s ease-out;
}

.queue-label {
  font-size: var(--fs-sm);
  font-weight: var(--fw-bold);
  color: var(--color-important);
}

/* Linked list visualization */
.ll-viz {
  display: flex;
  align-items: center;
  gap: var(--space-1);
  flex-wrap: wrap;
  justify-content: center;
}

.ll-node {
  display: flex;
  border: 2px solid rgba(var(--color-primary-rgb), 0.4);
  border-radius: var(--radius-sm);
  overflow: hidden;
  transition: all var(--transition-normal);
}

.ll-node:hover {
  border-color: var(--color-primary);
  box-shadow: var(--shadow-glow-primary);
}

.ll-data {
  padding: var(--space-2) var(--space-4);
  background: var(--bg-tertiary);
  font-family: var(--font-code);
  font-weight: var(--fw-bold);
  color: var(--text-heading);
  display: flex;
  align-items: center;
  border-right: 1px solid rgba(var(--color-primary-rgb), 0.3);
}

body[dir="rtl"] .ll-data {
  border-right: none;
  border-left: 1px solid rgba(var(--color-primary-rgb), 0.3);
}

.ll-next {
  padding: var(--space-2) var(--space-3);
  font-size: var(--fs-xs);
  color: var(--text-muted);
  display: flex;
  align-items: center;
  background: rgba(var(--color-primary-rgb), 0.05);
}

.ll-arrow {
  color: var(--color-important);
  font-weight: var(--fw-bold);
  font-size: var(--fs-lg);
  margin: 0 var(--space-2);
  animation: arrowPulse 1.5s ease-in-out infinite;
}

.ll-null {
  color: var(--color-secondary);
  font-family: var(--font-code);
  font-weight: var(--fw-bold);
  padding: var(--space-2) var(--space-3);
  border: 2px dashed rgba(var(--color-secondary-rgb), 0.3);
  border-radius: var(--radius-sm);
}

/* Tree visualization */
.tree-viz {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-4);
}

.tree-level {
  display: flex;
  justify-content: center;
  gap: var(--space-6);
}

.tree-node {
  width: 48px;
  height: 48px;
  background: var(--gradient-primary-subtle);
  border: 2px solid rgba(var(--color-primary-rgb), 0.4);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-code);
  font-weight: var(--fw-bold);
  color: var(--text-heading);
  transition: all var(--transition-normal);
  position: relative;
}

.tree-node:hover {
  border-color: var(--color-primary);
  box-shadow: var(--shadow-glow-primary);
  transform: scale(1.1);
}

.tree-node.highlight {
  background: var(--gradient-primary);
  color: white;
  box-shadow: var(--shadow-glow-primary);
  animation: nodeGlow 0.5s ease-out;
}

/* ============================================================
   10. CLASSIFICATION TREE
   ============================================================ */
.classification-tree {
  text-align: left;
  direction: ltr;
  padding: var(--space-4);
}

.tree-branch {
  padding-left: var(--space-8);
  border-left: 2px dashed rgba(var(--color-primary-rgb), 0.3);
  margin-top: var(--space-2);
}

body[dir="rtl"] .tree-branch {
  padding-left: 0;
  padding-right: var(--space-8);
  border-left: none;
  border-right: 2px dashed rgba(var(--color-primary-rgb), 0.3);
}

.tree-branch-item {
  padding: var(--space-2) var(--space-3);
  margin: var(--space-1) 0;
  font-size: var(--fs-sm);
  color: var(--text-primary);
  position: relative;
}

.tree-branch-item strong {
  color: var(--text-heading);
}

.tree-branch-item .tree-type {
  color: var(--color-secondary);
  font-family: var(--font-code);
  font-size: var(--fs-xs);
}

/* ============================================================
   11. QUIZ STYLES
   ============================================================ */
.quiz-container {
  max-width: 800px;
  margin: 0 auto;
}

.quiz-header {
  text-align: center;
  margin-bottom: var(--space-8);
}

.quiz-title {
  font-size: var(--fs-2xl);
  font-weight: var(--fw-bold);
  background: var(--gradient-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  margin-bottom: var(--space-2);
}

.quiz-info {
  color: var(--text-secondary);
  font-size: var(--fs-sm);
}

.quiz-progress {
  margin-bottom: var(--space-6);
}

.quiz-progress-bar {
  width: 100%;
  height: 8px;
  background: var(--bg-surface);
  border-radius: var(--radius-full);
  overflow: hidden;
  margin-bottom: var(--space-2);
}

.quiz-progress-fill {
  height: 100%;
  background: var(--gradient-primary);
  border-radius: var(--radius-full);
  transition: width var(--transition-normal);
}

.quiz-progress-text {
  display: flex;
  justify-content: space-between;
  font-size: var(--fs-xs);
  color: var(--text-muted);
}

.quiz-question-card {
  background: var(--bg-surface);
  backdrop-filter: blur(var(--blur-glass));
  border: 1px solid var(--border-glass);
  border-radius: var(--radius-lg);
  padding: var(--space-8);
  margin-bottom: var(--space-6);
  box-shadow: var(--shadow-card);
  animation: fadeInUp 0.4s ease-out;
}

.quiz-question-num {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-1) var(--space-3);
  background: var(--gradient-primary-subtle);
  border-radius: var(--radius-full);
  font-size: var(--fs-xs);
  color: var(--color-primary-light);
  font-weight: var(--fw-semibold);
  margin-bottom: var(--space-4);
}

.quiz-question-text {
  font-size: var(--fs-lg);
  font-weight: var(--fw-semibold);
  color: var(--text-heading);
  margin-bottom: var(--space-6);
  line-height: var(--lh-relaxed);
}

.quiz-question-text code {
  background: var(--bg-code);
  padding: 2px 8px;
  border-radius: var(--radius-xs);
  font-size: 0.9em;
  color: var(--color-secondary);
}

.quiz-options {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.quiz-option {
  display: flex;
  align-items: center;
  gap: var(--space-4);
  padding: var(--space-4) var(--space-5);
  background: var(--bg-input);
  border: 2px solid var(--border-primary);
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all var(--transition-normal);
  font-size: var(--fs-base);
  color: var(--text-primary);
}

.quiz-option:hover {
  border-color: rgba(var(--color-primary-rgb), 0.4);
  background: rgba(var(--color-primary-rgb), 0.05);
  transform: translateX(4px);
}

body[dir="rtl"] .quiz-option:hover {
  transform: translateX(-4px);
}

.quiz-option.selected {
  border-color: var(--color-primary);
  background: rgba(var(--color-primary-rgb), 0.1);
}

.quiz-option.correct {
  border-color: var(--color-success);
  background: rgba(var(--color-success-rgb), 0.1);
  animation: correctPulse 0.5s ease-out;
}

.quiz-option.wrong {
  border-color: var(--color-error);
  background: rgba(var(--color-important-rgb), 0.1);
  animation: shake 0.4s ease-out;
}

.quiz-option-letter {
  width: 36px;
  height: 36px;
  border-radius: var(--radius-sm);
  background: var(--bg-surface);
  border: 1px solid var(--border-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: var(--fw-bold);
  font-size: var(--fs-sm);
  color: var(--text-secondary);
  flex-shrink: 0;
  transition: all var(--transition-fast);
}

.quiz-option.selected .quiz-option-letter {
  background: var(--gradient-primary);
  border-color: transparent;
  color: white;
}

.quiz-option.correct .quiz-option-letter {
  background: var(--color-success);
  border-color: transparent;
  color: white;
}

.quiz-option.wrong .quiz-option-letter {
  background: var(--color-error);
  border-color: transparent;
  color: white;
}

.quiz-option-text { flex: 1; }

.quiz-explanation {
  margin-top: var(--space-4);
  padding: var(--space-4);
  border-radius: var(--radius-md);
  background: rgba(var(--color-info), 0.08);
  border: 1px solid rgba(var(--color-info), 0.2);
  font-size: var(--fs-sm);
  color: var(--color-info);
  animation: fadeIn 0.3s ease-out;
}

.quiz-nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-top: var(--space-6);
}

/* Quiz Results */
.quiz-results {
  text-align: center;
  padding: var(--space-10) 0;
}

.quiz-score-circle {
  width: 180px;
  height: 180px;
  border-radius: 50%;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  margin: 0 auto var(--space-6);
  position: relative;
}

.quiz-score-circle.excellent {
  background: rgba(var(--color-success-rgb), 0.1);
  border: 4px solid var(--color-success);
  box-shadow: 0 0 40px rgba(var(--color-success-rgb), 0.3);
}

.quiz-score-circle.good {
  background: rgba(var(--color-primary-rgb), 0.1);
  border: 4px solid var(--color-primary);
  box-shadow: var(--shadow-glow-primary);
}

.quiz-score-circle.average {
  background: rgba(var(--color-warning-rgb), 0.1);
  border: 4px solid var(--color-warning);
  box-shadow: 0 0 40px rgba(var(--color-warning-rgb), 0.3);
}

.quiz-score-circle.poor {
  background: rgba(var(--color-important-rgb), 0.1);
  border: 4px solid var(--color-important);
  box-shadow: 0 0 40px rgba(var(--color-important-rgb), 0.3);
}

.quiz-score-num {
  font-size: var(--fs-4xl);
  font-weight: var(--fw-extrabold);
  line-height: 1;
}

.quiz-score-label {
  font-size: var(--fs-sm);
  color: var(--text-muted);
  margin-top: var(--space-1);
}

.quiz-result-message {
  font-size: var(--fs-xl);
  font-weight: var(--fw-bold);
  margin-bottom: var(--space-2);
}

.quiz-result-detail {
  color: var(--text-secondary);
  margin-bottom: var(--space-6);
}

/* ============================================================
   12. HOME PAGE
   ============================================================ */
.home-hero {
  text-align: center;
  padding: var(--space-12) 0 var(--space-10);
  position: relative;
}

.home-hero-badge {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-2) var(--space-4);
  background: var(--gradient-primary-subtle);
  border: 1px solid rgba(var(--color-primary-rgb), 0.2);
  border-radius: var(--radius-full);
  font-size: var(--fs-sm);
  color: var(--color-primary-light);
  font-weight: var(--fw-medium);
  margin-bottom: var(--space-6);
  animation: fadeInDown 0.6s ease-out;
}

.home-hero-title {
  font-size: var(--fs-4xl);
  font-weight: var(--fw-extrabold);
  line-height: var(--lh-tight);
  margin-bottom: var(--space-4);
  animation: fadeInUp 0.6s ease-out 0.1s backwards;
}

.home-hero-title .gradient-text {
  background: var(--gradient-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.home-hero-desc {
  font-size: var(--fs-lg);
  color: var(--text-secondary);
  max-width: 600px;
  margin: 0 auto var(--space-8);
  animation: fadeInUp 0.6s ease-out 0.2s backwards;
}

.home-stats {
  display: flex;
  justify-content: center;
  gap: var(--space-8);
  margin-bottom: var(--space-10);
  animation: fadeInUp 0.6s ease-out 0.3s backwards;
}

.home-stat {
  text-align: center;
}

.home-stat-num {
  font-size: var(--fs-3xl);
  font-weight: var(--fw-extrabold);
  background: var(--gradient-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.home-stat-label {
  font-size: var(--fs-sm);
  color: var(--text-muted);
}

.home-lectures-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-4);
}

/* ── Hero CTA Buttons ── */
.hero-cta-group {
  display: flex;
  justify-content: center;
  gap: var(--space-4);
  flex-wrap: wrap;
  margin-top: var(--space-6);
}

.btn-cta-primary {
  display: inline-flex;
  align-items: center;
  gap: var(--space-3);
  padding: var(--space-4) var(--space-10);
  background: var(--gradient-primary);
  border: none;
  border-radius: var(--radius-xl);
  color: white;
  font-size: var(--fs-lg);
  font-weight: var(--fw-bold);
  cursor: pointer;
  transition: all var(--transition-normal);
  box-shadow: 0 6px 30px rgba(var(--color-primary-rgb), 0.4);
  position: relative;
  overflow: hidden;
}

.btn-cta-primary::before {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, rgba(255,255,255,0.2) 0%, transparent 50%);
  opacity: 0;
  transition: opacity var(--transition-fast);
}

.btn-cta-primary:hover {
  transform: translateY(-3px) scale(1.03);
  box-shadow: 0 10px 45px rgba(var(--color-primary-rgb), 0.55);
}

.btn-cta-primary:hover::before { opacity: 1; }

.cta-icon { font-size: 1.3rem; }
.cta-arrow { 
  transition: transform var(--transition-normal); 
  font-size: 1.2rem;
}
.btn-cta-primary:hover .cta-arrow { 
  transform: translateX(4px); 
}
body[dir="rtl"] .btn-cta-primary:hover .cta-arrow {
  transform: translateX(-4px);
}

.btn-cta-secondary {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-4) var(--space-8);
  background: var(--bg-surface);
  border: 2px solid rgba(var(--color-primary-rgb), 0.3);
  border-radius: var(--radius-xl);
  color: var(--color-primary-light);
  font-size: var(--fs-md);
  font-weight: var(--fw-semibold);
  cursor: pointer;
  transition: all var(--transition-normal);
  backdrop-filter: blur(10px);
}

.btn-cta-secondary:hover {
  border-color: var(--color-primary);
  background: rgba(var(--color-primary-rgb), 0.1);
  transform: translateY(-2px);
}

/* ── Home Section Title ── */
.home-section-title {
  font-size: var(--fs-2xl);
  font-weight: var(--fw-bold);
  color: var(--text-heading);
  margin: var(--space-8) 0 var(--space-4);
  text-align: center;
}

/* ── Interactive Stack Demo ── */
.home-demo-section {
  background: var(--bg-surface);
  backdrop-filter: blur(var(--blur-glass));
  -webkit-backdrop-filter: blur(var(--blur-glass));
  border: 1px solid var(--border-glass);
  border-radius: var(--radius-xl);
  padding: var(--space-8);
  margin: var(--space-10) 0;
  position: relative;
  overflow: hidden;
}

.home-demo-section::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: var(--gradient-glow-line);
}

.demo-header {
  text-align: center;
  margin-bottom: var(--space-6);
}

.demo-title {
  font-size: var(--fs-xl);
  font-weight: var(--fw-bold);
  color: var(--text-heading);
  margin-bottom: var(--space-2);
}

.demo-desc {
  color: var(--text-muted);
  font-size: var(--fs-sm);
}

.demo-body {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-8);
  flex-wrap: wrap;
}

.demo-stack-container {
  display: flex;
  flex-direction: column;
  align-items: center;
  min-width: 140px;
}

.demo-stack-label {
  color: var(--color-important);
  font-weight: var(--fw-bold);
  font-size: var(--fs-sm);
  margin-bottom: var(--space-2);
  animation: float 2s ease-in-out infinite;
}

.demo-stack {
  display: flex;
  flex-direction: column;
  min-height: 60px;
  min-width: 130px;
  border-left: 3px solid var(--color-primary);
  border-right: 3px solid var(--color-primary);
  padding: var(--space-2);
  gap: var(--space-1);
}

.demo-stack-base {
  background: var(--color-primary);
  color: white;
  text-align: center;
  padding: var(--space-1) var(--space-4);
  border-radius: 0 0 var(--radius-sm) var(--radius-sm);
  font-family: var(--font-code);
  font-weight: var(--fw-bold);
  font-size: var(--fs-xs);
  letter-spacing: 0.1em;
}

.demo-stack-item {
  padding: var(--space-2) var(--space-4);
  border: 2px solid;
  border-radius: var(--radius-xs);
  text-align: center;
  font-family: var(--font-code);
  font-weight: var(--fw-bold);
  color: var(--text-heading);
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  transition: all var(--transition-normal);
}

.demo-stack-item.is-top {
  animation: glowPulse 1.5s ease-in-out infinite !important;
}

.demo-top-badge {
  font-size: var(--fs-xs);
  padding: 1px 6px;
  border-radius: var(--radius-full);
  background: rgba(255,255,255,0.15);
  font-weight: var(--fw-semibold);
}

.demo-stack-empty {
  padding: var(--space-4);
  color: var(--text-muted);
  font-style: italic;
  text-align: center;
}

.demo-controls {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
  align-items: stretch;
  min-width: 120px;
}

.demo-controls input {
  padding: var(--space-3);
  border: 2px solid var(--border-primary);
  border-radius: var(--radius-sm);
  background: var(--bg-input);
  color: var(--text-primary);
  font-family: var(--font-code);
  font-size: var(--fs-lg);
  text-align: center;
  width: 100%;
  transition: border-color var(--transition-fast);
}

.demo-controls input:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 15px rgba(var(--color-primary-rgb), 0.2);
}

.demo-output {
  width: 100%;
  text-align: center;
  margin-top: var(--space-4);
  padding: var(--space-3);
  border-radius: var(--radius-sm);
  font-size: var(--fs-sm);
  font-weight: var(--fw-medium);
  min-height: 40px;
}

.demo-output-success {
  background: rgba(var(--color-success-rgb), 0.1);
  color: var(--color-success);
  border: 1px solid rgba(var(--color-success-rgb), 0.2);
}

.demo-output-error {
  background: rgba(var(--color-important-rgb), 0.1);
  color: var(--color-important);
  border: 1px solid rgba(var(--color-important-rgb), 0.2);
}

.demo-output-info {
  background: rgba(var(--color-secondary-rgb), 0.1);
  color: var(--color-secondary);
  border: 1px solid rgba(var(--color-secondary-rgb), 0.2);
}

/* ============================================================
   13. ANIMATIONS & KEYFRAMES
   ============================================================ */
@keyframes fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

@keyframes fadeInUp {
  from { opacity: 0; transform: translateY(20px); }
  to { opacity: 1; transform: translateY(0); }
}

@keyframes fadeInDown {
  from { opacity: 0; transform: translateY(-20px); }
  to { opacity: 1; transform: translateY(0); }
}

@keyframes slideInFromTop {
  from { opacity: 0; transform: translateY(-15px); }
  to { opacity: 1; transform: translateY(0); }
}

@keyframes slideInFromLeft {
  from { opacity: 0; transform: translateX(-15px); }
  to { opacity: 1; transform: translateX(0); }
}

@keyframes progressShine {
  0%, 100% { opacity: 0; }
  50% { opacity: 1; }
}

@keyframes arrowPulse {
  0%, 100% { opacity: 0.6; transform: translateX(0); }
  50% { opacity: 1; transform: translateX(3px); }
}

@keyframes nodeGlow {
  0% { box-shadow: 0 0 0 rgba(var(--color-primary-rgb), 0.5); }
  50% { box-shadow: 0 0 30px rgba(var(--color-primary-rgb), 0.5); }
  100% { box-shadow: var(--shadow-glow-primary); }
}

@keyframes correctPulse {
  0% { transform: scale(1); }
  50% { transform: scale(1.02); }
  100% { transform: scale(1); }
}

@keyframes shake {
  0%, 100% { transform: translateX(0); }
  25% { transform: translateX(-8px); }
  50% { transform: translateX(8px); }
  75% { transform: translateX(-4px); }
}

@keyframes float {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-10px); }
}

@keyframes glowPulse {
  0%, 100% { box-shadow: 0 0 20px rgba(var(--color-primary-rgb), 0.2); }
  50% { box-shadow: 0 0 40px rgba(var(--color-primary-rgb), 0.4), 0 0 60px rgba(var(--color-primary-rgb), 0.1); }
}

@keyframes rotateGlow {
  0% { transform: rotate(0deg); }
  100% { transform: rotate(360deg); }
}

@keyframes typewriter {
  from { width: 0; }
  to { width: 100%; }
}

@keyframes blink {
  0%, 100% { opacity: 1; }
  50% { opacity: 0; }
}

/* ============================================================
   14. RESPONSIVE
   ============================================================ */
@media (max-width: 1024px) {
  .main-content { padding: var(--space-6); }
}

@media (max-width: 768px) {
  .sidebar {
    transform: translateX(-100%);
  }
  
  body[dir="rtl"] .sidebar {
    transform: translateX(100%);
  }

  .sidebar.open {
    transform: translateX(0) !important;
  }

  .header {
    left: 0;
    right: 0;
  }

  body[dir="rtl"] .header {
    left: 0;
    right: 0;
  }

  .main-content {
    margin-left: 0;
    margin-right: 0;
    padding: var(--space-4);
  }

  body[dir="rtl"] .main-content {
    margin-right: 0;
  }



  .home-hero-title { font-size: var(--fs-2xl); }
  .home-stats { gap: var(--space-4); }
  .home-stat-num { font-size: var(--fs-xl); }

  .lecture-title { font-size: var(--fs-2xl); }

  .quiz-question-card { padding: var(--space-5); }
  .quiz-option { padding: var(--space-3) var(--space-4); }

  .ll-viz { gap: var(--space-2); }

  .sidebar-overlay {
    display: block;
    position: fixed;
    inset: 0;
    background: rgba(0,0,0,0.5);
    z-index: calc(var(--z-sidebar) - 1);
    opacity: 0;
    pointer-events: none;
    transition: opacity var(--transition-normal);
    backdrop-filter: blur(4px);
    -webkit-backdrop-filter: blur(4px);
  }

  .sidebar-overlay.open {
    opacity: 1;
    pointer-events: auto;
  }
}

@media (max-width: 480px) {
  :root {
    --header-height: 60px;
  }
  
  .home-hero { padding: var(--space-6) 0; }
  .home-hero-title { font-size: var(--fs-xl); }
  .home-hero-desc { font-size: var(--fs-base); }
  
  .lecture-title { font-size: var(--fs-xl); }
  .section-title { font-size: var(--fs-lg); }
  
  .array-cell { width: 40px; height: 40px; font-size: var(--fs-sm); }
}

/* ============================================================
   15. UTILITY CLASSES
   ============================================================ */
.text-center { text-align: center; }
.text-left { text-align: left; }
.text-right { text-align: right; }
.text-gradient {
  background: var(--gradient-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
.text-important { color: var(--color-important); font-weight: var(--fw-bold); }
.text-secondary { color: var(--text-secondary); }
.text-muted { color: var(--text-muted); }
.font-code { font-family: var(--font-code); }
.font-bold { font-weight: var(--fw-bold); }
.ltr { direction: ltr; text-align: left; }
.rtl { direction: rtl; text-align: right; }

.mt-2 { margin-top: var(--space-2); }
.mt-4 { margin-top: var(--space-4); }
.mt-6 { margin-top: var(--space-6); }
.mt-8 { margin-top: var(--space-8); }
.mb-2 { margin-bottom: var(--space-2); }
.mb-4 { margin-bottom: var(--space-4); }
.mb-6 { margin-bottom: var(--space-6); }

.flex { display: flex; }
.flex-col { flex-direction: column; }
.flex-center { align-items: center; justify-content: center; }
.flex-between { justify-content: space-between; }
.gap-2 { gap: var(--space-2); }
.gap-4 { gap: var(--space-4); }

.hidden { display: none !important; }
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border-width: 0;
}

/* Glow border effect */
.glow-border {
  position: relative;
}

.glow-border::after {
  content: '';
  position: absolute;
  inset: -1px;
  border-radius: inherit;
  background: conic-gradient(from 0deg, var(--color-primary), var(--color-secondary), var(--color-accent), var(--color-primary));
  z-index: -1;
  opacity: 0;
  transition: opacity var(--transition-normal);
  filter: blur(8px);
}

.glow-border:hover::after {
  opacity: 0.6;
}

/* ============================================================
   16. FOOTER
   ============================================================ */
.app-footer {
  margin-top: var(--space-12);
  padding: var(--space-6) 0;
  border-top: 1px solid var(--border-primary);
  text-align: center;
  animation: fadeInUp 0.5s ease-out backwards;
}

.footer-content {
  color: var(--text-secondary);
  font-size: var(--fs-sm);
  line-height: var(--lh-relaxed);
}

.developer-name {
  color: var(--color-primary-light);
  font-weight: var(--fw-bold);
  font-size: var(--fs-base);
  margin: 0 var(--space-1);
  text-decoration: none;
  display: inline-block;
  animation: electricSpark 4s infinite;
  transition: all var(--transition-fast);
}

.developer-name:hover {
  color: var(--color-secondary-light);
  text-shadow: 0 0 10px var(--color-secondary), 0 0 20px var(--color-secondary);
}

@keyframes electricSpark {
  0%, 90%, 100% {
    text-shadow: none;
    color: var(--color-primary-light);
  }
  92% {
    text-shadow: 0 0 5px #fff, 0 0 15px var(--color-secondary), 0 0 25px var(--color-secondary);
    color: #fff;
  }
  94% {
    text-shadow: none;
    color: var(--color-primary-light);
  }
  96% {
    text-shadow: 0 0 5px #fff, 0 0 15px var(--color-primary), 0 0 25px var(--color-primary);
    color: #fff;
  }
  98% {
    text-shadow: none;
    color: var(--color-primary-light);
  }
}

.developer-contact {
  margin-top: var(--space-2);
  font-family: var(--font-code);
  color: var(--color-secondary);
  font-weight: var(--fw-medium);
}

/* ── Sidebar collapsed on desktop (min-width: 769px) ── */
@media (min-width: 769px) {
  body.sidebar-closed .sidebar {
    transform: translateX(-100%);
  }
  body.sidebar-closed[dir="rtl"] .sidebar {
    transform: translateX(100%);
  }
  body.sidebar-closed .header {
    left: 0;
  }
  body.sidebar-closed[dir="rtl"] .header {
    right: 0;
  }
  body.sidebar-closed .main-content {
    margin-left: 0;
  }
  body.sidebar-closed[dir="rtl"] .main-content {
    margin-right: 0;
  }
}