/* ===== 42 Theory — Design System ===== */
/* Identical DA to Remotion videos (glassmorphism, dark, neon accents) */

:root {
  --bg-base: #050505;
  --bg-glass: rgba(255, 255, 255, 0.03);
  --bg-glass-border: rgba(255, 255, 255, 0.1);
  --bg-glass-header: rgba(255, 255, 255, 0.015);
  --bg-dark-panel: rgba(0, 0, 0, 0.2);

  --text-primary: #f8fafc;
  --text-secondary: #94a3b8;
  --text-dim: #475569;

  --accent-blue: #3b82f6;
  --accent-purple: #8b5cf6;
  --accent-green: #10b981;
  --accent-rose: #f43f5e;
  --accent-amber: #f59e0b;

  --font-code: "JetBrains Mono", monospace;
  --font-ui: "Outfit", "Inter", sans-serif;

  --glass-blur: blur(24px);
  --glass-radius: 24px;
  --glass-shadow:
    inset 0 1px 1px rgba(255,255,255,0.15),
    inset 0 0 0 1px rgba(255,255,255,0.06),
    0 30px 60px -15px rgba(20, 20, 50, 0.5),
    0 20px 40px -20px rgba(59, 130, 246, 0.2);
}

/* ===== Reset ===== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  font-family: var(--font-ui);
  background: var(--bg-base);
  color: var(--text-primary);
  line-height: 1.7;
  min-height: 100vh;
  overflow-x: hidden;
  width: 100%;
}
html {
  overflow-x: hidden;
}
a { color: var(--accent-blue); text-decoration: none; transition: color 0.2s; }
a:hover { color: #60a5fa; }

/* ===== Background layers (fixed) ===== */
.bg-image {
  position: fixed; inset: 0; z-index: 0;
  background: url('../img/bg42.png') center/cover no-repeat;
  filter: blur(40px) brightness(0.2) grayscale(0.6);
}
.bg-glow {
  position: fixed; inset: 0; z-index: 0;
  background:
    radial-gradient(circle at 15% 50%, rgba(59,130,246,0.15), transparent 40%),
    radial-gradient(circle at 85% 30%, rgba(139,92,246,0.15), transparent 40%);
  filter: blur(80px);
  animation: breathe 8s ease-in-out infinite alternate;
}
@keyframes breathe {
  from { transform: scale(1); }
  to { transform: scale(1.08); }
}
.bg-grid {
  position: fixed; inset: 0; z-index: 1; pointer-events: none;
  background-image:
    linear-gradient(rgba(255,255,255,0.03) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255,255,255,0.03) 1px, transparent 1px);
  background-size: 60px 60px;
  mask-image: radial-gradient(circle at center, black 40%, transparent 80%);
  -webkit-mask-image: radial-gradient(circle at center, black 40%, transparent 80%);
}
.bg-grain {
  position: fixed; inset: 0; z-index: 100; pointer-events: none;
  background-image: url('data:image/svg+xml,%3Csvg viewBox="0 0 200 200" xmlns="http://www.w3.org/2000/svg"%3E%3Cfilter id="n"%3E%3CfeTurbulence type="fractalNoise" baseFrequency="0.8" numOctaves="3" stitchTiles="stitch"/%3E%3C/filter%3E%3Crect width="100%25" height="100%25" filter="url(%23n)"/%3E%3C/svg%3E');
  opacity: 0.04;
  mix-blend-mode: overlay;
}

/* ===== Nav ===== */
.main-nav {
  position: fixed; top: 0; left: 0; right: 0; z-index: 50;
  background: rgba(5, 5, 5, 0.8);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--bg-glass-border);
}
.nav-inner {
  max-width: 1200px; margin: 0 auto;
  display: flex; align-items: center; justify-content: space-between;
  padding: 14px 24px;
}
.nav-logo {
  display: flex; align-items: center; gap: 10px;
  font-weight: 700; font-size: 18px; color: var(--text-primary);
}
.nav-logo img { opacity: 0.8; }
.nav-links { display: flex; gap: 28px; font-size: 14px; font-weight: 500; }
.nav-links a { color: var(--text-secondary); }
.nav-links a:hover, .nav-links a.active { color: var(--text-primary); }
.nav-toggle { display: none; background: none; border: none; color: var(--text-primary); font-size: 22px; cursor: pointer; }

/* ===== Main content ===== */
.main-content {
  position: relative; z-index: 2;
  max-width: 1200px; margin: 0 auto;
  padding: 100px 24px 60px;
  width: 100%;
  box-sizing: border-box;
}

/* ===== Glass Panel ===== */
.glass-panel {
  background: var(--bg-glass);
  backdrop-filter: var(--glass-blur);
  -webkit-backdrop-filter: var(--glass-blur);
  border-radius: var(--glass-radius);
  box-shadow: var(--glass-shadow);
  border: none;
  overflow: hidden;
}
.glass-header {
  padding: 16px 24px;
  border-bottom: 1px solid var(--bg-glass-border);
  background: var(--bg-glass-header);
  display: flex; align-items: center; gap: 12px;
}

/* ===== Hero (lesson page) ===== */
.lesson-hero {
  text-align: center;
  padding: 60px 20px 40px;
}
.lesson-hero .lesson-id {
  font-size: 14px; font-weight: 600; color: var(--accent-blue);
  text-transform: uppercase; letter-spacing: 3px; margin-bottom: 12px;
}
.lesson-hero h1 {
  font-size: 48px; font-weight: 800;
  background: linear-gradient(90deg, #61afef, #56b6c2);
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
  filter: drop-shadow(0 0 20px rgba(86,182,194,0.3));
  margin-bottom: 16px;
}
.lesson-hero .lesson-desc {
  font-size: 18px; color: var(--text-secondary); max-width: 600px; margin: 0 auto;
}
.lesson-prereqs {
  display: flex; gap: 8px; justify-content: center; margin-top: 20px; flex-wrap: wrap;
}
.lesson-prereqs a {
  font-size: 12px; padding: 4px 12px; border-radius: 20px;
  background: rgba(59,130,246,0.1); border: 1px solid rgba(59,130,246,0.2);
  color: var(--accent-blue); font-weight: 600;
}

/* ===== Lesson layout ===== */
.lesson-layout {
  display: grid;
  grid-template-columns: 220px 1fr;
  gap: 40px;
  align-items: start;
  min-width: 0;
  overflow: hidden;
}
.lesson-toc {
  position: sticky; top: 90px;
}
.lesson-toc h3 {
  font-size: 11px; font-weight: 600; color: var(--text-dim);
  text-transform: uppercase; letter-spacing: 2px; margin-bottom: 16px;
}
.lesson-toc a {
  display: block; padding: 6px 0; font-size: 13px;
  color: var(--text-secondary); border-left: 2px solid transparent;
  padding-left: 12px; transition: all 0.2s;
}
.lesson-toc a:hover, .lesson-toc a.active {
  color: var(--text-primary); border-left-color: var(--accent-blue);
}

/* ===== Lesson body ===== */
.lesson-body {
  min-width: 0;
  overflow-wrap: break-word;
  word-wrap: break-word;
}
.lesson-body h2 {
  font-size: 28px; font-weight: 700; margin: 48px 0 20px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--bg-glass-border);
}
.lesson-body h3 {
  font-size: 20px; font-weight: 600; margin: 32px 0 12px; color: var(--text-primary);
}
.lesson-body p {
  margin-bottom: 16px; color: var(--text-secondary); font-size: 16px; line-height: 1.8;
}
.lesson-body strong { color: var(--text-primary); }
.lesson-body code {
  font-family: var(--font-code); font-size: 14px;
  background: rgba(255,255,255,0.06); padding: 2px 8px; border-radius: 6px;
  color: #e5c07b;
  word-break: break-all;
}

/* ===== Tables ===== */
.table-wrap {
  margin: 20px 0; overflow-x: auto;
}
.table-wrap table {
  width: 100%; border-collapse: collapse;
  font-size: 14px;
}
.table-wrap th {
  text-align: left; padding: 10px 16px;
  background: var(--bg-dark-panel);
  color: var(--text-primary); font-weight: 600;
  border-bottom: 1px solid var(--bg-glass-border);
  font-size: 13px; text-transform: uppercase; letter-spacing: 0.5px;
}
.table-wrap td {
  padding: 10px 16px;
  border-bottom: 1px solid rgba(255,255,255,0.04);
  color: var(--text-secondary);
}
.table-wrap tr:hover td {
  background: rgba(255,255,255,0.02);
}
.table-wrap code {
  font-size: 13px;
}

/* ===== Info cards ===== */
.info-card {
  display: flex; gap: 0; margin: 20px 0; border-radius: 12px;
  background: var(--bg-dark-panel);
  border: 1px solid color-mix(in srgb, var(--card-color) 20%, transparent);
  overflow: hidden;
}
.info-bar {
  width: 4px; flex-shrink: 0;
  background: var(--card-color);
  box-shadow: 0 0 12px color-mix(in srgb, var(--card-color) 40%, transparent);
}
.info-content {
  padding: 16px 20px; font-size: 15px; color: var(--text-secondary); line-height: 1.6;
}
.info-icon { margin-right: 6px; }

/* ===== Concept list (cards grid) ===== */
.concept-list {
  display: flex; flex-wrap: wrap; gap: 16px; margin: 24px 0;
}
.concept-card {
  flex: 1 1 300px;
  background: var(--bg-dark-panel);
  border-radius: 16px;
  padding: 20px 24px;
  display: flex; align-items: center; gap: 18px;
  border: 1px solid rgba(255,255,255,0.05);
}
.concept-card .accent-bar {
  width: 4px; height: 44px; border-radius: 4px; flex-shrink: 0;
}
.concept-card .card-label {
  font-family: var(--font-ui); font-size: 18px; font-weight: 700;
}
.concept-card .card-desc {
  font-family: var(--font-code); font-size: 14px; color: rgba(255,255,255,0.55);
  margin-top: 4px;
}

/* ===== Video embed ===== */
.video-embed {
  margin: 30px 0; border-radius: 16px; overflow: hidden;
  aspect-ratio: 16 / 9;
}
.video-embed iframe {
  width: 100%; height: 100%; border: none;
}

/* ===== Lesson nav (prev/next) ===== */
.lesson-nav {
  display: flex; justify-content: space-between; margin-top: 60px;
  padding-top: 30px; border-top: 1px solid var(--bg-glass-border);
}
.lesson-nav a {
  display: flex; flex-direction: column; gap: 4px;
  padding: 16px 24px; border-radius: 16px;
  background: var(--bg-dark-panel); border: 1px solid var(--bg-glass-border);
  transition: all 0.2s; max-width: 45%;
}
.lesson-nav a:hover {
  border-color: var(--accent-blue);
  box-shadow: 0 0 20px rgba(59,130,246,0.1);
}
.lesson-nav .nav-label {
  font-size: 12px; color: var(--text-dim); text-transform: uppercase; letter-spacing: 1px;
}
.lesson-nav .nav-title {
  font-size: 16px; font-weight: 600; color: var(--text-primary);
}

/* ===== Landing: Cards grid ===== */
.hero-section {
  text-align: center; padding: 80px 0 60px;
}
.hero-section h1 {
  font-size: 64px; font-weight: 800;
  background: linear-gradient(90deg, #61afef, #56b6c2);
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
  filter: drop-shadow(0 0 30px rgba(86,182,194,0.4));
}
.hero-section p {
  font-size: 20px; color: var(--text-secondary); margin-top: 16px;
}

.section-title {
  font-size: 13px; font-weight: 600; color: var(--text-dim);
  text-transform: uppercase; letter-spacing: 2px;
  margin: 48px 0 20px;
  display: flex; align-items: center; gap: 12px;
}
.section-title::after {
  content: ''; flex: 1; height: 1px; background: var(--bg-glass-border);
}

.cards-grid {
  display: grid; grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 16px;
}
.lesson-card {
  display: flex; align-items: center; gap: 16px;
  padding: 20px 24px; border-radius: 16px;
  background: var(--bg-dark-panel);
  border: 1px solid rgba(255,255,255,0.05);
  transition: all 0.25s;
}
.lesson-card:hover {
  border-color: var(--accent-blue);
  box-shadow: 0 0 25px rgba(59,130,246,0.1);
  transform: translateY(-2px);
}
.lesson-card .card-num {
  font-size: 14px; font-weight: 700; font-family: var(--font-code);
  width: 44px; height: 44px; border-radius: 12px;
  display: flex; align-items: center; justify-content: center;
  flex-shrink: 0;
}
.lesson-card .card-info .card-title {
  font-size: 16px; font-weight: 600; color: var(--text-primary);
}
.lesson-card .card-info .card-section {
  font-size: 12px; color: var(--text-dim); margin-top: 2px;
}

/* ===== Quiz ===== */
.quiz {
  margin: 48px 0;
}
.quiz-header h2 {
  border-bottom: none; margin-bottom: 8px;
}
.quiz-subtitle {
  color: var(--text-dim); font-size: 14px; margin-bottom: 32px;
}
.quiz-question {
  background: var(--bg-dark-panel);
  border: 1px solid var(--bg-glass-border);
  border-radius: 16px;
  padding: 24px;
  margin-bottom: 16px;
  transition: border-color 0.3s;
}
.quiz-question.correct { border-color: var(--accent-green); }
.quiz-question.wrong { border-color: var(--accent-rose); }

.quiz-q-header {
  display: flex; align-items: flex-start; gap: 14px; margin-bottom: 16px;
}
.quiz-num {
  font-family: var(--font-code); font-size: 14px; font-weight: 700;
  width: 32px; height: 32px; border-radius: 10px;
  display: flex; align-items: center; justify-content: center;
  background: rgba(59,130,246,0.1); color: var(--accent-blue);
  flex-shrink: 0;
}
.quiz-q-text {
  font-size: 16px; font-weight: 500; color: var(--text-primary); line-height: 1.5;
}
.quiz-choices {
  display: flex; flex-direction: column; gap: 8px;
}
.quiz-choice {
  display: block; width: 100%; text-align: left;
  padding: 12px 18px; border-radius: 12px;
  background: rgba(255,255,255,0.03);
  border: 1px solid rgba(255,255,255,0.08);
  color: var(--text-secondary);
  font-family: var(--font-ui); font-size: 15px;
  cursor: pointer; transition: all 0.2s;
}
.quiz-choice:hover:not(.selected):not(.disabled) {
  border-color: var(--accent-blue);
  color: var(--text-primary);
  background: rgba(59,130,246,0.05);
}
.quiz-choice.selected {
  border-color: var(--accent-blue);
  background: rgba(59,130,246,0.1);
  color: var(--text-primary);
  font-weight: 600;
}
.quiz-choice.correct-answer {
  border-color: var(--accent-green);
  background: rgba(16,185,129,0.1);
  color: var(--accent-green);
  font-weight: 600;
}
.quiz-choice.wrong-answer {
  border-color: var(--accent-rose);
  background: rgba(244,63,94,0.1);
  color: var(--accent-rose);
  opacity: 0.7;
}
.quiz-choice.disabled { cursor: default; pointer-events: none; }

.quiz-explain {
  margin-top: 12px; padding: 14px 18px;
  border-radius: 10px;
  background: rgba(255,255,255,0.02);
  border-left: 3px solid var(--accent-blue);
}
.quiz-explain p {
  font-size: 14px; color: var(--text-secondary); margin: 0; line-height: 1.6;
}

.quiz-result {
  margin-top: 24px; padding: 20px 24px;
  border-radius: 16px; text-align: center;
  font-size: 18px; font-weight: 600;
}
.quiz-result.good {
  background: rgba(16,185,129,0.1); border: 1px solid rgba(16,185,129,0.3);
  color: var(--accent-green);
}
.quiz-result.mid {
  background: rgba(245,158,11,0.1); border: 1px solid rgba(245,158,11,0.3);
  color: var(--accent-amber);
}
.quiz-result.bad {
  background: rgba(244,63,94,0.1); border: 1px solid rgba(244,63,94,0.3);
  color: var(--accent-rose);
}

/* ===== Footer ===== */
.main-footer {
  position: relative; z-index: 2;
  border-top: 1px solid var(--bg-glass-border);
  padding: 30px 24px; margin-top: 80px;
}
.footer-inner {
  max-width: 1200px; margin: 0 auto;
  display: flex; justify-content: space-between; align-items: center;
}
.footer-links { display: flex; gap: 24px; }
.footer-links a { color: var(--text-dim); font-size: 13px; }
.footer-links a:hover { color: var(--text-secondary); }
.footer-copy { color: var(--text-dim); font-size: 13px; }