/* ═══ CSS Variables ═══ */
:root {
  --cosmic-deep: #0a0a1a;
  --cosmic-blue: #0d1b3e;
  --nebula-purple: #3a1c5c;
  --starlight-gold: #f0c040;
  --starlight-pale: #ffe9a0;
  --star-white: #e8e8f0;
  --accent-cyan: #40e0d0;
  --card-glass: rgba(15, 20, 50, 0.65);
  --card-border: rgba(100, 140, 220, 0.25);
  --text-primary: #e0e4f0;
  --text-secondary: #9098b8;
  --glow-gold: 0 0 40px rgba(240, 192, 64, 0.3);
  --glow-purple: 0 0 60px rgba(130, 60, 200, 0.4);
  --nav-bg: rgba(10, 10, 26, 0.85);
  --input-bg: rgba(255,255,255,0.04);
  --input-border: rgba(200,200,230,0.18);
  --tag-hover-bg: rgba(240,192,64,0.1);
  --tag-ai-bg: rgba(64, 224, 208, 0.1);
  --tag-dev-bg: rgba(240, 192, 64, 0.1);
  --tag-design-bg: rgba(224, 128, 192, 0.1);
  --sidebar-link-hover: rgba(240,192,64,0.08);
  --timeline-line: rgba(100,140,220,0.3);
  --divider: rgba(200,200,230,0.15);
  --filter-btn-bg: rgba(255,255,255,0.04);
  --filter-btn-border: rgba(200,200,230,0.2);
  --filter-active-bg: rgba(240,192,64,0.12);
  --tab-border: rgba(100,140,220,0.2);
}

[data-theme="light"] {
  --cosmic-deep: #f0f2f8;
  --cosmic-blue: #e0e6f4;
  --nebula-purple: #e8ddf5;
  --starlight-gold: #c89420;
  --starlight-pale: #8b6914;
  --star-white: #333340;
  --accent-cyan: #208878;
  --card-glass: rgba(255, 255, 255, 0.78);
  --card-border: rgba(60, 60, 100, 0.15);
  --text-primary: #1a1a2e;
  --text-secondary: #585870;
  --glow-gold: 0 0 40px rgba(180, 140, 30, 0.2);
  --glow-purple: 0 0 60px rgba(100, 40, 160, 0.15);
  --nav-bg: rgba(240, 242, 248, 0.88);
  --input-bg: rgba(0,0,0,0.03);
  --input-border: rgba(0,0,0,0.12);
  --tag-hover-bg: rgba(180,140,30,0.12);
  --tag-ai-bg: rgba(32, 136, 120, 0.1);
  --tag-dev-bg: rgba(200, 148, 32, 0.1);
  --tag-design-bg: rgba(180, 100, 150, 0.1);
  --sidebar-link-hover: rgba(180,140,30,0.1);
  --timeline-line: rgba(60,60,100,0.2);
  --divider: rgba(0,0,0,0.1);
  --filter-btn-bg: rgba(0,0,0,0.03);
  --filter-btn-border: rgba(0,0,0,0.12);
  --filter-active-bg: rgba(180,140,30,0.15);
  --tab-border: rgba(0,0,0,0.1);
}

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

body {
  font-family: 'Noto Sans SC', sans-serif;
  background: var(--cosmic-deep);
  color: var(--text-primary);
  overflow-x: hidden;
  cursor: default;
}

/* ═══ Canvas Starfield ═══ */
#starfield {
  position: fixed;
  top: 0; left: 0;
  width: 100%; height: 100%;
  z-index: 0;
  pointer-events: none;
}

/* ═══ Floating Orbs ═══ */
.orb {
  position: fixed;
  border-radius: 50%;
  filter: blur(80px);
  pointer-events: none;
  z-index: 0;
  opacity: 0.35;
}
.orb-1 { width: 600px; height: 600px; background: radial-gradient(circle, #4a2080 0%, transparent 70%); top: -200px; left: -150px; animation: orbDrift1 20s ease-in-out infinite; }
.orb-2 { width: 500px; height: 500px; background: radial-gradient(circle, #1a4070 0%, transparent 70%); bottom: -200px; right: -100px; animation: orbDrift2 25s ease-in-out infinite; }
.orb-3 { width: 400px; height: 400px; background: radial-gradient(circle, #5a3a20 0%, transparent 70%); top: 60%; left: 50%; animation: orbDrift3 22s ease-in-out infinite; }

@keyframes orbDrift1 {
  0%, 100% { transform: translate(0, 0); }
  33% { transform: translate(80px, 50px); }
  66% { transform: translate(-40px, -30px); }
}
@keyframes orbDrift2 {
  0%, 100% { transform: translate(0, 0); }
  33% { transform: translate(-60px, -40px); }
  66% { transform: translate(50px, 30px); }
}
@keyframes orbDrift3 {
  0%, 100% { transform: translate(0, 0); }
  50% { transform: translate(60px, -50px); }
}

/* ═══ Main Container ═══ */
.main-container {
  position: relative;
  z-index: 1;
  max-width: 1400px;
  margin: 0 auto;
  padding: 0 2rem;
}

/* ═══ Page Wrapper (for sub-pages) ═══ */
.page-wrapper {
  position: relative;
  z-index: 1;
  max-width: 1400px;
  margin: 0 auto;
  padding: 7rem 2rem 3rem;
  min-height: 100vh;
}

/* ═══ Navigation ═══ */
.nav {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 100;
  padding: 1.2rem 3rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  transition: background 0.4s, backdrop-filter 0.4s;
}
.nav.scrolled {
  background: var(--nav-bg);
  backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--card-border);
}
.nav-logo {
  font-family: 'Orbitron', monospace;
  font-size: 1.5rem;
  font-weight: 900;
  background: linear-gradient(135deg, var(--starlight-gold), var(--starlight-pale));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  letter-spacing: 0.08em;
  text-decoration: none;
  cursor: pointer;
}
.nav-links {
  display: flex;
  gap: 2.5rem;
  list-style: none;
}
.nav-links a {
  color: var(--text-secondary);
  text-decoration: none;
  font-size: 0.95rem;
  font-weight: 400;
  letter-spacing: 0.04em;
  transition: color 0.3s, text-shadow 0.3s;
  position: relative;
}
.nav-links a::after {
  content: '';
  position: absolute;
  bottom: -4px; left: 0;
  width: 0; height: 1px;
  background: var(--starlight-gold);
  transition: width 0.3s;
}
.nav-links a:hover {
  color: var(--starlight-pale);
  text-shadow: 0 0 20px rgba(240, 192, 64, 0.4);
}
.nav-links a:hover::after { width: 100%; }

/* ═══ Buttons ═══ */
.btn {
  padding: 0.85rem 2.5rem;
  border-radius: 50px;
  font-family: 'Space Grotesk', sans-serif;
  font-size: 0.95rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  cursor: pointer;
  transition: all 0.35s;
  text-decoration: none;
  position: relative;
  overflow: hidden;
  display: inline-block;
  border: none;
}
.btn-primary {
  background: linear-gradient(135deg, #f0c040, #d4a020);
  color: #0a0a1a;
  box-shadow: 0 0 30px rgba(240, 192, 64, 0.25);
}
.btn-primary:hover {
  box-shadow: 0 0 50px rgba(240, 192, 64, 0.5);
  transform: translateY(-2px);
}
.btn-ghost {
  background: transparent;
  color: var(--text-primary);
  border: 1px solid var(--card-border);
  backdrop-filter: blur(10px);
}
.btn-ghost:hover {
  border-color: var(--accent-cyan);
  box-shadow: 0 0 25px rgba(64, 224, 208, 0.2);
  color: var(--accent-cyan);
}
.btn-sm {
  padding: 0.5rem 1.5rem;
  font-size: 0.8rem;
}

/* ═══ Section Common ═══ */
.section {
  padding: 8rem 0;
  position: relative;
}
.section-header {
  text-align: center;
  margin-bottom: 5rem;
}
.section-label {
  font-family: 'Space Grotesk', sans-serif;
  font-size: 0.8rem;
  letter-spacing: 0.25em;
  color: var(--accent-cyan);
  text-transform: uppercase;
  margin-bottom: 1rem;
}
.section-title {
  font-family: 'Orbitron', monospace;
  font-size: clamp(2rem, 5vw, 3.5rem);
  font-weight: 700;
  letter-spacing: 0.04em;
}
.section-title em {
  font-style: normal;
  background: linear-gradient(135deg, var(--starlight-gold), var(--starlight-pale));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}
.section-desc {
  margin-top: 1rem;
  color: var(--text-secondary);
  font-size: 1.1rem;
  font-weight: 300;
}

/* ═══ Books Grid ═══ */
.books-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 2.5rem;
}
.book-card {
  perspective: 1200px;
  height: 420px;
}
.book-card-inner {
  position: relative;
  width: 100%;
  height: 100%;
  transition: transform 0.6s cubic-bezier(0.23, 1, 0.32, 1);
  transform-style: preserve-3d;
}
.book-card:hover .book-card-inner {
  transform: rotateY(8deg) rotateX(4deg);
}
.book-card-face {
  position: absolute;
  inset: 0;
  border-radius: 20px;
  padding: 2rem;
  background: var(--card-glass);
  backdrop-filter: blur(20px);
  border: 1px solid var(--card-border);
  display: flex;
  flex-direction: column;
  transition: box-shadow 0.5s, border-color 0.5s;
  overflow: hidden;
  cursor: pointer;
}
.book-card:hover .book-card-face {
  border-color: rgba(240, 192, 64, 0.4);
  box-shadow: var(--glow-gold), 0 20px 60px rgba(0, 0, 0, 0.4);
}
.book-card-glow {
  position: absolute;
  top: -50%; left: -50%;
  width: 200%; height: 200%;
  background: radial-gradient(circle at var(--mx, 50%) var(--my, 50%), rgba(240, 192, 64, 0.12) 0%, transparent 50%);
  pointer-events: none;
  opacity: 0;
  transition: opacity 0.4s;
}
.book-card:hover .book-card-glow { opacity: 1; }
.book-cover {
  width: 80px;
  height: 110px;
  border-radius: 8px;
  background: linear-gradient(135deg, var(--starlight-gold), #b8860b);
  margin-bottom: 1.5rem;
  position: relative;
  overflow: hidden;
  box-shadow: 0 8px 30px rgba(0,0,0,0.3);
  flex-shrink: 0;
}
.book-cover::after {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0; bottom: 0;
  background: linear-gradient(45deg, transparent 48%, rgba(255,255,255,0.1) 50%, transparent 52%);
}
.book-cover.c2 { background: linear-gradient(135deg, #6c3cb0, #4a2080); }
.book-cover.c3 { background: linear-gradient(135deg, #1a6090, #0d3b5e); }
.book-cover.c4 { background: linear-gradient(135deg, #c04860, #8b2040); }
.book-cover.c5 { background: linear-gradient(135deg, #40a070, #1a6040); }
.book-cover.c6 { background: linear-gradient(135deg, #d08030, #a05010); }
.book-tag {
  display: inline-block;
  padding: 0.25rem 0.85rem;
  border-radius: 50px;
  font-size: 0.7rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  margin-bottom: 1rem;
  border: 1px solid;
}
.book-tag.ai { color: #40e0d0; border-color: rgba(64, 224, 208, 0.3); }
.book-tag.dev { color: #f0c040; border-color: rgba(240, 192, 64, 0.3); }
.book-tag.design { color: #e080c0; border-color: rgba(224, 128, 192, 0.3); }
.book-title {
  font-size: 1.25rem;
  font-weight: 700;
  letter-spacing: 0.02em;
  margin-bottom: 0.5rem;
}
.book-author {
  font-size: 0.85rem;
  color: var(--text-secondary);
  margin-bottom: 1rem;
}
.book-desc {
  font-size: 0.9rem;
  color: var(--text-secondary);
  line-height: 1.6;
  flex: 1;
}
.book-stars {
  display: flex;
  gap: 0.2rem;
  margin-top: 1rem;
  color: var(--starlight-gold);
  font-size: 0.9rem;
}

/* ═══ Courses ═══ */
.courses-layout {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(360px, 1fr));
  gap: 2rem;
}
.course-card {
  background: var(--card-glass);
  backdrop-filter: blur(20px);
  border: 1px solid var(--card-border);
  border-radius: 20px;
  padding: 2rem;
  transition: all 0.5s cubic-bezier(0.23, 1, 0.32, 1);
  position: relative;
  overflow: hidden;
  cursor: pointer;
}
.course-card::before {
  content: '';
  position: absolute;
  top: 0; left: 0;
  width: 100%; height: 3px;
  background: linear-gradient(90deg, var(--accent-cyan), var(--starlight-gold), #e080c0);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.6s cubic-bezier(0.23, 1, 0.32, 1);
}
.course-card:hover::before { transform: scaleX(1); }
.course-card:hover {
  transform: translateY(-8px);
  border-color: rgba(240, 192, 64, 0.35);
  box-shadow: var(--glow-gold), 0 30px 60px rgba(0, 0, 0, 0.5);
}
.course-icon {
  width: 56px; height: 56px;
  border-radius: 16px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.6rem;
  margin-bottom: 1.5rem;
  position: relative;
}
.course-icon::after {
  content: '';
  position: absolute;
  inset: -4px;
  border-radius: 20px;
  border: 2px solid transparent;
  background: linear-gradient(135deg, var(--starlight-gold), var(--accent-cyan)) border-box;
  -webkit-mask: linear-gradient(#fff 0 0) padding-box, linear-gradient(#fff 0 0);
  -webkit-mask-composite: xor;
  mask-composite: exclude;
  opacity: 0.6;
}
.course-level {
  display: inline-block;
  padding: 0.2rem 0.8rem;
  border-radius: 50px;
  font-size: 0.7rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  margin-bottom: 0.8rem;
}
.course-level.beginner { background: rgba(64, 224, 208, 0.1); color: #40e0d0; }
.course-level.intermediate { background: rgba(240, 192, 64, 0.1); color: #f0c040; }
.course-level.advanced { background: rgba(224, 128, 192, 0.1); color: #e080c0; }
.course-title {
  font-size: 1.2rem;
  font-weight: 700;
  margin-bottom: 0.6rem;
}
.course-info {
  display: flex;
  gap: 1.5rem;
  margin-top: 1.2rem;
  font-size: 0.8rem;
  color: var(--text-secondary);
}
.course-info span {
  display: flex;
  align-items: center;
  gap: 0.35rem;
}

/* ═══ Features Grid ═══ */
.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1px;
  background: rgba(100, 140, 220, 0.1);
  border-radius: 24px;
  overflow: hidden;
}
.feature-item {
  background: var(--card-glass);
  backdrop-filter: blur(20px);
  padding: 3rem 2rem;
  text-align: center;
  transition: all 0.4s;
  position: relative;
  overflow: hidden;
}
.feature-item::after {
  content: '';
  position: absolute;
  inset: 0;
  background: radial-gradient(circle at center, rgba(240, 192, 64, 0.08) 0%, transparent 60%);
  opacity: 0;
  transition: opacity 0.4s;
}
.feature-item:hover::after { opacity: 1; }
.feature-item:hover {
  background: rgba(20, 30, 60, 0.8);
}
.feature-num {
  font-family: 'Orbitron', monospace;
  font-size: 3rem;
  font-weight: 900;
  background: linear-gradient(135deg, var(--starlight-gold), var(--starlight-pale));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  line-height: 1;
  margin-bottom: 1rem;
}
.feature-name {
  font-size: 1.05rem;
  font-weight: 600;
  margin-bottom: 0.5rem;
}
.feature-desc {
  font-size: 0.85rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

/* ═══ Stats Row ═══ */
.stats-row {
  display: flex;
  justify-content: center;
  gap: 6rem;
  flex-wrap: wrap;
  padding: 4rem 0;
}
.stat-item {
  text-align: center;
}
.stat-num {
  font-family: 'Orbitron', monospace;
  font-size: 3.5rem;
  font-weight: 900;
  background: linear-gradient(135deg, var(--starlight-gold), var(--starlight-pale));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  line-height: 1;
}
.stat-label {
  margin-top: 0.5rem;
  font-size: 0.9rem;
  color: var(--text-secondary);
  letter-spacing: 0.06em;
}

/* ═══ Footer ═══ */
.footer {
  text-align: center;
  padding: 6rem 2rem 3rem;
  border-top: 1px solid var(--card-border);
}
.footer-logo {
  font-family: 'Orbitron', monospace;
  font-size: 1.3rem;
  font-weight: 900;
  background: linear-gradient(135deg, var(--starlight-gold), var(--starlight-pale));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  letter-spacing: 0.08em;
  margin-bottom: 1rem;
}
.footer-text {
  color: var(--text-secondary);
  font-size: 0.85rem;
}

/* ═══ Reveal Animations ═══ */
.reveal {
  opacity: 0;
  transform: translateY(50px);
  transition: opacity 0.8s ease-out, transform 0.8s cubic-bezier(0.23, 1, 0.32, 1);
}
.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}
.reveal-delay-1 { transition-delay: 0.1s; }
.reveal-delay-2 { transition-delay: 0.2s; }
.reveal-delay-3 { transition-delay: 0.3s; }
.reveal-delay-4 { transition-delay: 0.4s; }

/* ═══ Mobile Menu Button ═══ */
.mobile-menu-btn {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  flex-direction: column;
  gap: 5px;
  padding: 5px;
  z-index: 101;
}
.mobile-menu-btn span {
  display: block;
  width: 24px; height: 2px;
  background: var(--text-primary);
  transition: all 0.3s;
}

/* ═══ Language Toggle ═══ */
.lang-toggle {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  background: var(--input-bg);
  border: 1px solid var(--filter-btn-border);
  border-radius: 50px;
  padding: 0.3rem;
  cursor: pointer;
  font-family: 'Space Grotesk', sans-serif;
  font-size: 0.78rem;
  font-weight: 600;
  color: var(--text-secondary);
  transition: all 0.3s;
  white-space: nowrap;
}
.lang-toggle:hover {
  border-color: var(--starlight-gold);
  color: var(--starlight-pale);
  box-shadow: 0 0 15px rgba(240,192,64,0.15);
}
.lang-toggle span {
  padding: 0.3rem 0.7rem;
  border-radius: 50px;
  transition: all 0.3s;
}
.lang-toggle span.active {
  background: linear-gradient(135deg, var(--starlight-gold), #d4a020);
  color: #0a0a1a;
}

/* ═══ Theme Toggle ═══ */
.theme-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 38px; height: 38px;
  border-radius: 50%;
  background: var(--input-bg);
  border: 1px solid var(--filter-btn-border);
  cursor: pointer;
  font-size: 1.1rem;
  color: var(--text-secondary);
  transition: all 0.3s;
  padding: 0;
}
.theme-toggle:hover {
  border-color: var(--starlight-gold);
  color: var(--starlight-pale);
  box-shadow: 0 0 15px rgba(240,192,64,0.15);
}

/* ═══ Keyframe Animations ═══ */
@keyframes fadeInUp {
  from { opacity: 0; transform: translateY(30px); }
  to { opacity: 1; transform: translateY(0); }
}
@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.3; }
}

/* ═══ Glass Card (generic) ═══ */
.glass-card {
  background: var(--card-glass);
  backdrop-filter: blur(20px);
  border: 1px solid var(--card-border);
  border-radius: 20px;
  padding: 2rem;
}

/* ═══ Breadcrumb ═══ */
.breadcrumb {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  margin-bottom: 2rem;
  font-size: 0.85rem;
  color: var(--text-secondary);
}
.breadcrumb a {
  color: var(--text-secondary);
  text-decoration: none;
  transition: color 0.3s;
}
.breadcrumb a:hover { color: var(--starlight-pale); }
.breadcrumb .sep { color: rgba(100, 140, 220, 0.4); }

/* ═══ Page Title ═══ */
.page-title {
  font-family: 'Orbitron', monospace;
  font-size: clamp(2rem, 5vw, 3rem);
  font-weight: 700;
  letter-spacing: 0.04em;
  margin-bottom: 0.5rem;
}
.page-title em {
  font-style: normal;
  background: linear-gradient(135deg, var(--starlight-gold), var(--starlight-pale));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

/* ═══ Tabs ═══ */
.tabs {
  display: flex;
  gap: 0;
  border-bottom: 1px solid var(--tab-border);
  margin-bottom: 2rem;
}
.tab-btn {
  padding: 0.8rem 1.8rem;
  background: none;
  border: none;
  color: var(--text-secondary);
  font-family: 'Space Grotesk', sans-serif;
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.3s;
  border-bottom: 2px solid transparent;
}
.tab-btn.active {
  color: var(--starlight-pale);
  border-bottom-color: var(--starlight-gold);
}
.tab-btn:hover { color: var(--text-primary); }
.tab-panel { display: none; }
.tab-panel.active { display: block; }

/* ═══ Form Elements ═══ */
.form-group {
  margin-bottom: 1.5rem;
}
.form-label {
  display: block;
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--text-secondary);
  margin-bottom: 0.5rem;
}
.form-input {
  width: 100%;
  padding: 0.85rem 1.2rem;
  background: rgba(255,255,255,0.04);
  border: 1px solid rgba(200,200,230,0.2);
  border-radius: 12px;
  color: var(--text-primary);
  font-family: 'Space Grotesk', sans-serif;
  font-size: 0.95rem;
  transition: all 0.3s;
  outline: none;
}
.form-input:focus {
  border-color: var(--starlight-gold);
  box-shadow: 0 0 20px rgba(240, 192, 64, 0.15);
  background: rgba(255,255,255,0.06);
}
.form-input.error {
  border-color: #e04060;
  box-shadow: 0 0 15px rgba(224, 64, 96, 0.2);
}
.form-error {
  font-size: 0.78rem;
  color: #e04060;
  margin-top: 0.4rem;
  display: none;
}
.form-checkbox {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  font-size: 0.85rem;
  color: var(--text-secondary);
}

/* ═══ Badge / Tag ═══ */
.tag {
  display: inline-block;
  padding: 0.25rem 0.85rem;
  border-radius: 50px;
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  border: 1px solid;
  cursor: pointer;
  transition: all 0.3s;
}
.tag.active, .tag:hover { background: rgba(240,192,64,0.1); border-color: var(--starlight-gold); color: var(--starlight-pale); }
.tag-ai { color: #40e0d0; border-color: rgba(64,224,208,0.3); }
.tag-dev { color: #f0c040; border-color: rgba(240,192,64,0.3); }
.tag-design { color: #e080c0; border-color: rgba(224,128,192,0.3); }

/* ═══ Light Theme Overrides ═══ */
[data-theme="light"] .nav-links.mobile-open {
  background: rgba(240, 242, 248, 0.95);
  border-bottom-color: rgba(0, 0, 0, 0.1);
}
[data-theme="light"] .features-grid {
  background: rgba(0, 0, 0, 0.06);
}
[data-theme="light"] .feature-item:hover {
  background: rgba(240, 240, 250, 0.9);
}
[data-theme="light"] .btn-primary {
  color: #fff;
}
[data-theme="light"] .lang-toggle span.active,
[data-theme="light"] .theme-toggle.active {
  color: #fff;
}
[data-theme="light"] .orb {
  opacity: 0.22;
}
[data-theme="light"] .submit-btn {
  color: #fff;
}

/* ═══ Responsive ═══ */
@media (max-width: 900px) {
  .features-grid { grid-template-columns: 1fr; }
  .stats-row { gap: 3rem; }
  .nav-links { display: none; }
  .mobile-menu-btn { display: flex; }
  .nav { padding: 1rem 1.5rem; }
  .books-grid { grid-template-columns: 1fr; }
  .courses-layout { grid-template-columns: 1fr; }
  .section { padding: 5rem 0; }
}

@media (max-width: 600px) {
  .main-container, .page-wrapper { padding-left: 1.2rem; padding-right: 1.2rem; }
  .stat-num { font-size: 2.5rem; }
  .book-card { height: 380px; }
}