/* ============================================
   CodeShelf — Dark Academic E-Library Theme
   Palette: Rosewood Library + Deep Burgundy
   ============================================ */

:root {
  --bg-primary: #0e0a0d;
  --bg-secondary: #160d12;
  --bg-card: #1c1118;
  --bg-card-hover: #231520;
  --accent-gold: #c9a87c;
  --accent-gold-light: #e2c99a;
  --accent-rose: #7d3c50;
  --accent-rose-light: #a05068;
  --accent-java: #f89820;
  --accent-css: #2965f1;
  --accent-html: #e44d26;
  --accent-python: #3572a5;
  --text-primary: #f2ede4;
  --text-secondary: #b8a898;
  --text-muted: #7a6a5a;
  --border: rgba(201,168,124,0.15);
  --border-hover: rgba(201,168,124,0.35);
  --font-display: 'Playfair Display', Georgia, serif;
  --font-body: 'Outfit', sans-serif;
  --font-mono: 'DM Mono', 'Courier New', monospace;
}

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

html { scroll-behavior: smooth; }

body {
  background: var(--bg-primary);
  color: var(--text-primary);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.7;
  overflow-x: hidden;
}

/* ---- Ambient Background ---- */
.ambient-bg {
  position: fixed; inset: 0; z-index: 0; pointer-events: none; overflow: hidden;
}
.orb {
  position: absolute; border-radius: 50%; filter: blur(80px); opacity: 0.18;
  animation: orbFloat 12s ease-in-out infinite;
}
.orb-1 { width: 500px; height: 500px; background: #7d3c50; top: -100px; left: -100px; animation-delay: 0s; }
.orb-2 { width: 400px; height: 400px; background: #4a1c2b; top: 40%; right: -80px; animation-delay: 4s; }
.orb-3 { width: 350px; height: 350px; background: #c9a87c; bottom: -80px; left: 30%; animation-delay: 8s; }
@keyframes orbFloat {
  0%, 100% { transform: translateY(0) scale(1); }
  50% { transform: translateY(-30px) scale(1.05); }
}

/* ---- Navbar ---- */
.navbar {
  position: fixed; top: 0; left: 0; right: 0; z-index: 100;
  display: flex; align-items: center; gap: 2rem;
  padding: 1rem 3rem;
  background: rgba(14,10,13,0.85);
  backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--border);
}
.nav-brand { display: flex; align-items: center; gap: 0.6rem; text-decoration: none; }
.brand-icon { font-size: 1.4rem; }
.brand-name {
  font-family: var(--font-display); font-size: 1.3rem; font-weight: 700;
  color: var(--accent-gold); letter-spacing: 0.02em;
}
.nav-links {
  display: flex; list-style: none; gap: 0.3rem; margin-left: auto;
}
.nav-link {
  text-decoration: none; color: var(--text-secondary); font-size: 0.9rem;
  font-weight: 500; padding: 0.4rem 0.9rem; border-radius: 6px;
  transition: all 0.2s; letter-spacing: 0.03em;
}
.nav-link:hover, .nav-link.active {
  color: var(--accent-gold); background: rgba(201,168,124,0.1);
}
.lang-java:hover { color: var(--accent-java); background: rgba(248,152,32,0.1); }
.lang-css:hover  { color: var(--accent-css);  background: rgba(41,101,241,0.1); }
.lang-html:hover { color: var(--accent-html); background: rgba(228,77,38,0.1); }
.lang-python:hover { color: var(--accent-python); background: rgba(53,114,165,0.1); }
.hamburger {
  display: none; background: none; border: 1px solid var(--border);
  color: var(--accent-gold); font-size: 1.2rem; padding: 0.4rem 0.7rem;
  border-radius: 6px; cursor: pointer; margin-left: auto;
}
.mobile-menu {
  display: none; position: fixed; top: 64px; left: 0; right: 0; z-index: 99;
  background: rgba(14,10,13,0.97); backdrop-filter: blur(20px);
  flex-direction: column; padding: 1rem 2rem;
  border-bottom: 1px solid var(--border);
}
.mobile-menu a {
  color: var(--text-secondary); text-decoration: none; padding: 0.8rem 0;
  border-bottom: 1px solid var(--border); font-size: 1rem;
}
.mobile-menu.open { display: flex; }

/* ---- Hero ---- */
.hero {
  position: relative; z-index: 1;
  min-height: 100vh; display: flex; align-items: center;
  padding: 8rem 3rem 4rem;
  gap: 4rem; max-width: 1300px; margin: 0 auto;
}
.hero-content { flex: 1; max-width: 600px; }
.hero-eyebrow {
  font-family: var(--font-mono); font-size: 0.8rem; letter-spacing: 0.15em;
  color: var(--accent-gold); text-transform: uppercase; margin-bottom: 1.2rem;
  opacity: 0; animation: fadeUp 0.8s 0.2s forwards;
}
.hero-title {
  font-family: var(--font-display); font-size: clamp(2.8rem, 5vw, 4.5rem);
  font-weight: 700; line-height: 1.1; color: var(--text-primary);
  margin-bottom: 1.5rem;
  opacity: 0; animation: fadeUp 0.8s 0.4s forwards;
}
.hero-title em { color: var(--accent-gold); font-style: italic; }
.hero-subtitle {
  font-size: 1.1rem; color: var(--text-secondary); line-height: 1.8;
  margin-bottom: 2.5rem; max-width: 480px;
  opacity: 0; animation: fadeUp 0.8s 0.6s forwards;
}
.hero-cta {
  display: flex; gap: 1rem; flex-wrap: wrap; margin-bottom: 3rem;
  opacity: 0; animation: fadeUp 0.8s 0.8s forwards;
}
.btn-primary {
  display: inline-block; padding: 0.85rem 2rem; border-radius: 8px;
  background: linear-gradient(135deg, var(--accent-rose), #4a1c2b);
  color: var(--accent-gold-light); font-weight: 600; text-decoration: none;
  font-size: 0.95rem; letter-spacing: 0.03em;
  border: 1px solid rgba(201,168,124,0.3);
  transition: all 0.3s; box-shadow: 0 4px 20px rgba(125,60,80,0.4);
}
.btn-primary:hover {
  transform: translateY(-2px); box-shadow: 0 8px 30px rgba(125,60,80,0.6);
  background: linear-gradient(135deg, #a05068, #5a2535);
}
.btn-secondary {
  display: inline-block; padding: 0.85rem 2rem; border-radius: 8px;
  background: transparent; color: var(--accent-gold);
  font-weight: 500; text-decoration: none; font-size: 0.95rem;
  border: 1px solid var(--border-hover); transition: all 0.3s;
}
.btn-secondary:hover {
  background: rgba(201,168,124,0.1); transform: translateY(-2px);
}
.hero-stats {
  display: flex; align-items: center; gap: 2rem;
  opacity: 0; animation: fadeUp 0.8s 1s forwards;
}
.stat { display: flex; flex-direction: column; }
.stat-num {
  font-family: var(--font-display); font-size: 2rem; font-weight: 700;
  color: var(--accent-gold); line-height: 1;
}
.stat-label { font-size: 0.75rem; color: var(--text-muted); letter-spacing: 0.08em; text-transform: uppercase; }
.stat-divider { width: 1px; height: 40px; background: var(--border); }

/* ---- Book Stack Visual ---- */
.hero-visual {
  flex: 0 0 auto; display: flex; align-items: center; justify-content: center;
  opacity: 0; animation: fadeIn 1s 0.5s forwards;
}
.book-stack {
  display: flex; gap: 0.8rem; align-items: flex-end;
  perspective: 800px;
}
.book {
  display: flex; cursor: pointer;
  transition: transform 0.4s cubic-bezier(0.34,1.56,0.64,1);
  transform-style: preserve-3d;
}
.book:hover { transform: translateY(-20px) rotateY(-15deg); }
.book-spine {
  width: 28px; background: rgba(0,0,0,0.4);
  display: flex; align-items: center; justify-content: center;
  font-family: var(--font-mono); font-size: 0.55rem; font-weight: 500;
  letter-spacing: 0.15em; writing-mode: vertical-rl;
  color: rgba(255,255,255,0.6); border-radius: 4px 0 0 4px;
  padding: 0.5rem 0;
}
.book-cover {
  width: 90px; border-radius: 0 6px 6px 0;
  display: flex; flex-direction: column; align-items: center;
  justify-content: center; gap: 0.5rem; padding: 1.5rem 0.5rem;
}
.book-icon { font-size: 1.8rem; }
.book-label {
  font-family: var(--font-mono); font-size: 0.65rem; font-weight: 500;
  letter-spacing: 0.1em; color: rgba(255,255,255,0.8);
}
.book-java .book-cover { background: linear-gradient(160deg, #b8620a, #7a3d05); height: 200px; }
.book-java .book-spine { background: #7a3d05; }
.book-css .book-cover  { background: linear-gradient(160deg, #1a4db8, #0d2d7a); height: 170px; }
.book-css .book-spine  { background: #0d2d7a; }
.book-html .book-cover { background: linear-gradient(160deg, #c43d1a, #7a2010); height: 185px; }
.book-html .book-spine { background: #7a2010; }
.book-python .book-cover { background: linear-gradient(160deg, #1e5c8a, #0d3355); height: 160px; }
.book-python .book-spine { background: #0d3355; }

/* ---- Sections ---- */
.library-section, .cheatsheet-section {
  position: relative; z-index: 1;
  padding: 6rem 3rem; max-width: 1300px; margin: 0 auto;
}
.section-header { text-align: center; margin-bottom: 4rem; }
.section-eyebrow {
  font-family: var(--font-mono); font-size: 0.75rem; letter-spacing: 0.2em;
  color: var(--accent-gold); text-transform: uppercase; margin-bottom: 0.8rem;
}
.section-title {
  font-family: var(--font-display); font-size: clamp(2rem, 3.5vw, 3rem);
  font-weight: 700; color: var(--text-primary); margin-bottom: 1rem;
}
.section-desc { color: var(--text-secondary); font-size: 1rem; max-width: 500px; margin: 0 auto; }

/* ---- Language Cards ---- */
.lang-cards {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1.5rem;
}
.lang-card {
  position: relative; display: flex; flex-direction: column;
  background: var(--bg-card); border: 1px solid var(--border);
  border-radius: 16px; padding: 2rem; text-decoration: none;
  overflow: hidden; transition: all 0.35s cubic-bezier(0.34,1.2,0.64,1);
}
.lang-card:hover {
  transform: translateY(-8px); border-color: var(--border-hover);
  background: var(--bg-card-hover);
  box-shadow: 0 20px 60px rgba(0,0,0,0.5);
}
.card-glow {
  position: absolute; inset: 0; border-radius: 16px; opacity: 0;
  transition: opacity 0.35s; pointer-events: none;
}
.lang-card-java .card-glow  { background: radial-gradient(circle at 50% 0%, rgba(248,152,32,0.12), transparent 70%); }
.lang-card-css .card-glow   { background: radial-gradient(circle at 50% 0%, rgba(41,101,241,0.12), transparent 70%); }
.lang-card-html .card-glow  { background: radial-gradient(circle at 50% 0%, rgba(228,77,38,0.12), transparent 70%); }
.lang-card-python .card-glow{ background: radial-gradient(circle at 50% 0%, rgba(53,114,165,0.12), transparent 70%); }
.lang-card:hover .card-glow { opacity: 1; }
.card-header { display: flex; align-items: center; justify-content: space-between; margin-bottom: 1.2rem; }
.card-icon { font-size: 2rem; }
.card-badge {
  font-family: var(--font-mono); font-size: 0.65rem; letter-spacing: 0.1em;
  padding: 0.25rem 0.6rem; border-radius: 20px; text-transform: uppercase;
  background: rgba(201,168,124,0.1); color: var(--accent-gold); border: 1px solid var(--border);
}
.card-title {
  font-family: var(--font-display); font-size: 1.8rem; font-weight: 700;
  color: var(--text-primary); margin-bottom: 0.8rem;
}
.lang-card-java .card-title  { color: var(--accent-java); }
.lang-card-css .card-title   { color: var(--accent-css); }
.lang-card-html .card-title  { color: var(--accent-html); }
.lang-card-python .card-title{ color: var(--accent-python); }
.card-desc { color: var(--text-secondary); font-size: 0.9rem; line-height: 1.7; margin-bottom: 1.5rem; flex: 1; }
.card-topics { display: flex; flex-wrap: wrap; gap: 0.4rem; margin-bottom: 1.5rem; }
.topic-tag {
  font-family: var(--font-mono); font-size: 0.7rem; padding: 0.2rem 0.6rem;
  border-radius: 4px; background: rgba(255,255,255,0.05); color: var(--text-muted);
  border: 1px solid rgba(255,255,255,0.08);
}
.card-footer { display: flex; align-items: center; justify-content: space-between; }
.card-count { font-family: var(--font-mono); font-size: 0.75rem; color: var(--text-muted); }
.card-arrow {
  font-size: 1.2rem; color: var(--accent-gold); opacity: 0;
  transform: translateX(-8px); transition: all 0.3s;
}
.lang-card:hover .card-arrow { opacity: 1; transform: translateX(0); }

/* ---- Cheat Sheet Grid ---- */
.cheatsheet-section { background: rgba(22,13,18,0.5); border-radius: 24px; }
.cheatsheet-grid {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 1rem;
}
.cs-card {
  display: flex; align-items: center; gap: 1rem;
  background: var(--bg-card); border: 1px solid var(--border);
  border-radius: 12px; padding: 1.4rem 1.6rem; text-decoration: none;
  transition: all 0.3s; position: relative; overflow: hidden;
}
.cs-card:hover { transform: translateY(-4px); border-color: var(--border-hover); }
.cs-icon { font-size: 1.8rem; flex-shrink: 0; }
.cs-info h4 { font-family: var(--font-display); font-size: 1rem; color: var(--text-primary); margin-bottom: 0.2rem; }
.cs-info p  { font-size: 0.8rem; color: var(--text-muted); }
.cs-arrow { margin-left: auto; font-size: 1.1rem; color: var(--accent-gold); opacity: 0; transition: opacity 0.3s; }
.cs-card:hover .cs-arrow { opacity: 1; }
.cs-java:hover  { box-shadow: 0 8px 30px rgba(248,152,32,0.15); }
.cs-css:hover   { box-shadow: 0 8px 30px rgba(41,101,241,0.15); }
.cs-html:hover  { box-shadow: 0 8px 30px rgba(228,77,38,0.15); }
.cs-python:hover{ box-shadow: 0 8px 30px rgba(53,114,165,0.15); }

/* ---- Quote Banner ---- */
.quote-banner {
  position: relative; z-index: 1;
  text-align: center; padding: 5rem 3rem;
  background: linear-gradient(135deg, rgba(74,28,43,0.3), rgba(14,10,13,0.8));
  border-top: 1px solid var(--border); border-bottom: 1px solid var(--border);
}
.quote-banner blockquote {
  font-family: var(--font-display); font-size: clamp(1.2rem, 2.5vw, 1.8rem);
  font-style: italic; color: var(--text-secondary); line-height: 1.7;
  max-width: 700px; margin: 0 auto 1rem;
}
.quote-banner blockquote em { color: var(--accent-gold); }
.quote-banner cite { font-family: var(--font-mono); font-size: 0.8rem; color: var(--text-muted); letter-spacing: 0.1em; }

/* ---- Footer ---- */
.footer {
  position: relative; z-index: 1;
  text-align: center; padding: 3rem;
  border-top: 1px solid var(--border);
}
.footer-brand { display: flex; align-items: center; justify-content: center; gap: 0.6rem; margin-bottom: 0.8rem; }
.footer-tagline { color: var(--text-muted); font-size: 0.9rem; margin-bottom: 1.5rem; }
.footer-links { display: flex; justify-content: center; gap: 2rem; margin-bottom: 1.5rem; }
.footer-links a { color: var(--text-secondary); text-decoration: none; font-size: 0.9rem; transition: color 0.2s; }
.footer-links a:hover { color: var(--accent-gold); }
.footer-copy { font-family: var(--font-mono); font-size: 0.75rem; color: var(--text-muted); }

/* ---- Animations ---- */
@keyframes fadeUp {
  from { opacity: 0; transform: translateY(24px); }
  to   { opacity: 1; transform: translateY(0); }
}
@keyframes fadeIn {
  from { opacity: 0; } to { opacity: 1; }
}

/* ---- Responsive ---- */
@media (max-width: 900px) {
  .hero { flex-direction: column; padding: 7rem 1.5rem 3rem; text-align: center; }
  .hero-cta { justify-content: center; }
  .hero-stats { justify-content: center; }
  .hero-subtitle { margin: 0 auto 2.5rem; }
  .navbar { padding: 1rem 1.5rem; }
  .nav-links { display: none; }
  .hamburger { display: block; }
  .library-section, .cheatsheet-section { padding: 4rem 1.5rem; }
}
@media (max-width: 600px) {
  .lang-cards { grid-template-columns: 1fr; }
  .cheatsheet-grid { grid-template-columns: 1fr; }
  .book-stack { gap: 0.5rem; }
  .book-cover { width: 70px; }
}