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

:root {
  --bg-deep: #0a0e1a;
  --bg-surface: #111827;
  --bg-card: rgba(17, 24, 39, 0.7);
  --glass: rgba(255,255,255,0.04);
  --glass-border: rgba(255,255,255,0.08);
  --text-primary: #f1f5f9;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;
  --phase1: #06b6d4;
  --phase1-glow: rgba(6, 182, 212, 0.15);
  --phase1-bg: rgba(6, 182, 212, 0.06);
  --phase2: #10b981;
  --phase2-glow: rgba(16, 185, 129, 0.15);
  --phase2-bg: rgba(16, 185, 129, 0.06);
  --phase3: #f59e0b;
  --phase3-glow: rgba(245, 158, 11, 0.15);
  --phase3-bg: rgba(245, 158, 11, 0.06);
  --accent-red: #ef4444;
  --accent-green: #22c55e;
  --gold: #fbbf24;
}

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

html { scroll-behavior: smooth; scroll-padding-top: 80px; }

body {
  font-family: 'Inter', sans-serif;
  background: var(--bg-deep);
  color: var(--text-primary);
  line-height: 1.7;
  min-height: 100vh;
  overflow-x: hidden;
}

/* ===== PROGRESS BAR ===== */
.progress-bar {
  position: fixed; top: 0; left: 0;
  height: 3px; background: linear-gradient(90deg, var(--phase1), var(--phase2), var(--phase3));
  z-index: 1000; transition: width 0.1s linear;
}

/* ===== HEADER ===== */
.site-header {
  position: fixed; top: 12px; left: 12px; right: 12px;
  background: rgba(10, 14, 26, 0.85);
  backdrop-filter: blur(20px);
  border: 1px solid var(--glass-border);
  border-radius: 16px;
  padding: 12px 24px;
  z-index: 100;
  display: flex; align-items: center; justify-content: space-between;
}
.header-title {
  font-size: 14px; font-weight: 600;
  background: linear-gradient(135deg, var(--phase1), var(--phase2));
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
}
.header-version {
  font-size: 11px; font-family: 'JetBrains Mono', monospace;
  color: var(--text-muted); background: var(--glass);
  padding: 4px 10px; border-radius: 20px;
  border: 1px solid var(--glass-border);
}
.author-link {
  color: var(--gold); text-decoration: none;
  font-size: 13px; font-weight: 600;
  display: flex; align-items: center; gap: 6px;
  padding: 6px 14px; border-radius: 20px;
  border: 1px solid rgba(251, 191, 36, 0.3);
  background: rgba(251, 191, 36, 0.08);
  transition: all 0.3s;
}
.author-link:hover { background: rgba(251,191,36,0.15); border-color: var(--gold); }

/* ===== TIMELINE NAV (Desktop) ===== */
.timeline-nav {
  position: fixed; left: 24px; top: 50%;
  transform: translateY(-50%);
  z-index: 90; display: flex; flex-direction: column;
  gap: 2px;
}
.timeline-nav::before {
  content: ''; position: absolute;
  left: 15px; top: 0; bottom: 0; width: 2px;
  background: var(--glass-border);
}
.nav-item {
  display: flex; align-items: center; gap: 12px;
  padding: 6px 0; cursor: pointer; position: relative;
  text-decoration: none; color: var(--text-muted);
  font-size: 12px; font-weight: 500;
  transition: all 0.3s;
}
.nav-dot {
  width: 10px; height: 10px; border-radius: 50%;
  border: 2px solid var(--glass-border);
  background: var(--bg-deep);
  z-index: 1; transition: all 0.3s;
  flex-shrink: 0;
}
.nav-label {
  opacity: 1; white-space: nowrap;
  transition: all 0.3s;
  font-size: 11px; color: var(--text-muted);
}
.nav-item:hover .nav-label { color: var(--text-secondary); }
.nav-item.active .nav-dot { border-color: var(--phase1); background: var(--phase1); box-shadow: 0 0 12px var(--phase1-glow); }
.nav-item.active .nav-label { color: var(--text-primary); font-weight: 600; }
.nav-item[data-phase="1"] .nav-dot { border-color: var(--phase1); }
.nav-item[data-phase="2"] .nav-dot { border-color: var(--phase2); }
.nav-item[data-phase="3"] .nav-dot { border-color: var(--phase3); }
.nav-item[data-phase="1"].active .nav-dot { background: var(--phase1); box-shadow: 0 0 12px var(--phase1-glow); }
.nav-item[data-phase="2"].active .nav-dot { background: var(--phase2); box-shadow: 0 0 12px var(--phase2-glow); }
.nav-item[data-phase="3"].active .nav-dot { background: var(--phase3); box-shadow: 0 0 12px var(--phase3-glow); }
.nav-phase-label {
  font-size: 10px; font-weight: 800; text-transform: uppercase;
  letter-spacing: 1.5px; padding: 12px 0 4px 32px;
  margin-top: 4px;
}
.nav-phase-label:first-child { padding-top: 0; margin-top: 0; }
.nav-phase-label.pl1 { color: var(--phase1); }
.nav-phase-label.pl2 { color: var(--phase2); }
.nav-phase-label.pl3 { color: var(--phase3); }

/* ===== MAIN CONTENT ===== */
.main-content {
  max-width: 820px;
  margin: 0 auto;
  padding: 100px 24px 80px;
}

/* ===== HERO ===== */
.hero {
  text-align: center;
  padding: 60px 0 40px;
  position: relative;
}
.hero::before {
  content: ''; position: absolute;
  top: -60px; left: 50%; transform: translateX(-50%);
  width: 500px; height: 500px;
  background: radial-gradient(circle, rgba(6,182,212,0.08) 0%, transparent 70%);
  pointer-events: none;
}
.hero-badge {
  display: inline-block; font-size: 11px; font-weight: 600;
  text-transform: uppercase; letter-spacing: 2px;
  color: var(--phase1); padding: 6px 16px;
  border: 1px solid rgba(6,182,212,0.3);
  border-radius: 20px; background: var(--phase1-bg);
  margin-bottom: 20px;
}
.hero h1 {
  font-size: clamp(28px, 5vw, 42px);
  font-weight: 800; line-height: 1.2;
  margin-bottom: 16px;
  background: linear-gradient(135deg, #f1f5f9 30%, var(--phase1) 100%);
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
}
.hero-subtitle {
  font-size: 17px; color: var(--text-secondary);
  max-width: 600px; margin: 0 auto 28px;
}
.hero-quote {
  font-size: 14px; font-style: italic;
  color: var(--phase1); padding: 14px 24px;
  border-left: 3px solid var(--phase1);
  background: var(--phase1-bg);
  border-radius: 0 12px 12px 0;
  max-width: 540px; margin: 0 auto;
  text-align: left;
}

/* ===== PHASE HEADER ===== */
.phase-header {
  display: flex; align-items: center; gap: 14px;
  margin: 56px 0 24px; padding: 16px 20px;
  border-radius: 14px;
}
.phase-header.p1 { background: var(--phase1-bg); border: 1px solid rgba(6,182,212,0.15); }
.phase-header.p2 { background: var(--phase2-bg); border: 1px solid rgba(16,185,129,0.15); }
.phase-header.p3 { background: var(--phase3-bg); border: 1px solid rgba(245,158,11,0.15); }
.phase-num {
  font-size: 13px; font-weight: 700;
  padding: 6px 14px; border-radius: 8px;
  font-family: 'JetBrains Mono', monospace;
}
.p1 .phase-num { background: rgba(6,182,212,0.15); color: var(--phase1); }
.p2 .phase-num { background: rgba(16,185,129,0.15); color: var(--phase2); }
.p3 .phase-num { background: rgba(245,158,11,0.15); color: var(--phase3); }
.phase-header h2 { font-size: 20px; font-weight: 700; }
.p1 h2 { color: var(--phase1); }
.p2 h2 { color: var(--phase2); }
.p3 h2 { color: var(--phase3); }

/* ===== STEP SECTION ===== */
.step-section {
  margin-bottom: 40px; padding: 28px;
  background: var(--bg-card);
  border: 1px solid var(--glass-border);
  border-radius: 16px;
  backdrop-filter: blur(10px);
  transition: border-color 0.3s;
}
.step-section:hover { border-color: rgba(255,255,255,0.12); }
.step-title {
  display: flex; align-items: center; gap: 12px;
  margin-bottom: 16px;
}
.step-num {
  font-size: 12px; font-weight: 700;
  font-family: 'JetBrains Mono', monospace;
  width: 32px; height: 32px;
  display: flex; align-items: center; justify-content: center;
  border-radius: 8px; flex-shrink: 0;
}
.step-section[data-phase="1"] .step-num { background: rgba(6,182,212,0.15); color: var(--phase1); }
.step-section[data-phase="2"] .step-num { background: rgba(16,185,129,0.15); color: var(--phase2); }
.step-section[data-phase="3"] .step-num { background: rgba(245,158,11,0.15); color: var(--phase3); }
.step-title h3 { font-size: 18px; font-weight: 700; }
.step-desc { color: var(--text-secondary); font-size: 14px; margin-bottom: 20px; }

/* ===== TABLES ===== */
.table-wrap { overflow-x: auto; margin: 16px 0; border-radius: 10px; border: 1px solid var(--glass-border); }
table {
  width: 100%; border-collapse: collapse;
  font-size: 13px;
}
th {
  background: rgba(255,255,255,0.04);
  text-align: left; padding: 10px 14px;
  font-weight: 600; color: var(--text-primary);
  border-bottom: 1px solid var(--glass-border);
  white-space: nowrap;
}
td {
  padding: 10px 14px; border-bottom: 1px solid var(--glass-border);
  color: var(--text-secondary);
}
tr:last-child td { border-bottom: none; }
tr:hover td { background: rgba(255,255,255,0.02); }

/* ===== CALLOUT ===== */
.callout {
  padding: 14px 18px; border-radius: 10px;
  font-size: 13px; margin: 16px 0;
  border-left: 3px solid;
}
.callout.info { border-color: var(--phase1); background: var(--phase1-bg); color: var(--phase1); }
.callout.warn { border-color: var(--phase3); background: var(--phase3-bg); color: var(--phase3); }
.callout.danger { border-color: var(--accent-red); background: rgba(239,68,68,0.06); color: #f87171; }
.callout.success { border-color: var(--accent-green); background: rgba(34,197,94,0.06); color: var(--accent-green); }

/* ===== TRAFFIC LIGHT ===== */
.traffic-light { display: inline-block; width: 10px; height: 10px; border-radius: 50%; margin-right: 6px; }
.tl-green { background: #22c55e; box-shadow: 0 0 6px rgba(34,197,94,0.4); }
.tl-yellow { background: #eab308; box-shadow: 0 0 6px rgba(234,179,8,0.4); }
.tl-red { background: #ef4444; box-shadow: 0 0 6px rgba(239,68,68,0.4); }

/* ===== TEMPLATE BOX ===== */
.template-box {
  background: var(--bg-deep);
  border: 1px solid var(--glass-border);
  border-radius: 12px; padding: 20px;
  font-family: 'JetBrains Mono', monospace;
  font-size: 12px; line-height: 2;
  color: var(--text-secondary); overflow-x: auto;
  white-space: pre; word-break: keep-all;
}

/* ===== CHECKLIST ===== */
.checklist { list-style: none; padding: 0; }
.checklist li {
  display: flex; align-items: flex-start; gap: 10px;
  padding: 8px 0; font-size: 13px;
  color: var(--text-secondary);
  border-bottom: 1px solid var(--glass-border);
}
.checklist li:last-child { border-bottom: none; }
.check-box {
  width: 18px; height: 18px; border-radius: 4px;
  border: 2px solid var(--glass-border);
  flex-shrink: 0; margin-top: 2px;
}

/* ===== COMPARISON GRID ===== */
.compare-grid {
  display: grid; grid-template-columns: 1fr 1fr;
  gap: 16px; margin: 16px 0;
}
.compare-card {
  padding: 18px; border-radius: 12px;
  border: 1px solid var(--glass-border);
}
.compare-card.before { background: rgba(239,68,68,0.04); border-color: rgba(239,68,68,0.15); }
.compare-card.after { background: rgba(34,197,94,0.04); border-color: rgba(34,197,94,0.15); }
.compare-card h4 { font-size: 13px; font-weight: 700; margin-bottom: 10px; }
.compare-card.before h4 { color: #f87171; }
.compare-card.after h4 { color: #4ade80; }
.compare-card ul { list-style: none; padding: 0; font-size: 13px; color: var(--text-secondary); }
.compare-card li { padding: 4px 0; padding-left: 16px; position: relative; }
.compare-card.before li::before { content: '✕'; position: absolute; left: 0; color: #f87171; font-size: 11px; }
.compare-card.after li::before { content: '✓'; position: absolute; left: 0; color: #4ade80; font-size: 11px; }

/* ===== FOUR MODE GRID ===== */
.mode-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; margin: 16px 0; }
.mode-card {
  padding: 16px; border-radius: 12px;
  background: var(--glass); border: 1px solid var(--glass-border);
}
.mode-card h4 { font-size: 13px; font-weight: 700; margin-bottom: 6px; color: var(--text-primary); }
.mode-card p { font-size: 12px; color: var(--text-muted); }
.mode-card .mode-tag {
  display: inline-block; font-size: 10px; font-weight: 600;
  padding: 2px 8px; border-radius: 4px; margin-bottom: 8px;
}
.mode-card:nth-child(1) .mode-tag { background: rgba(6,182,212,0.15); color: var(--phase1); }
.mode-card:nth-child(2) .mode-tag { background: rgba(16,185,129,0.15); color: var(--phase2); }
.mode-card:nth-child(3) .mode-tag { background: rgba(245,158,11,0.15); color: var(--phase3); }
.mode-card:nth-child(4) .mode-tag { background: rgba(239,68,68,0.15); color: #f87171; }

/* ===== FOOTER ===== */
.site-footer {
  text-align: center; padding: 40px 24px;
  border-top: 1px solid var(--glass-border);
  color: var(--text-muted); font-size: 13px;
}
.footer-brand { color: var(--gold); font-weight: 600; text-decoration: none; }
.footer-brand:hover { text-decoration: underline; }

/* ===== SCROLL TOP ===== */
.scroll-top {
  position: fixed; bottom: 24px; right: 24px;
  width: 42px; height: 42px; border-radius: 12px;
  background: var(--bg-surface); border: 1px solid var(--glass-border);
  color: var(--text-secondary); cursor: pointer;
  display: flex; align-items: center; justify-content: center;
  font-size: 18px; opacity: 0; transition: all 0.3s;
  z-index: 90;
}
.scroll-top.visible { opacity: 1; }
.scroll-top:hover { background: var(--phase1); color: white; border-color: var(--phase1); }

/* ===== MOBILE NAV ===== */
.mobile-nav {
  display: none;
  position: fixed; bottom: 0; left: 0; right: 0;
  background: rgba(10,14,26,0.95);
  backdrop-filter: blur(20px);
  border-top: 1px solid var(--glass-border);
  z-index: 100; padding: 8px 12px;
  justify-content: space-around;
}
.mob-item {
  display: flex; flex-direction: column; align-items: center;
  gap: 3px; text-decoration: none;
  font-size: 10px; color: var(--text-muted);
  padding: 6px 8px; border-radius: 8px;
  transition: all 0.2s;
}
.mob-item.active { color: var(--phase1); }
.mob-dot { width: 6px; height: 6px; border-radius: 50%; background: currentColor; }

/* ===== RESPONSIVE ===== */
@media (max-width: 800px) {
  .timeline-nav { display: none; }
  .mobile-nav { display: flex; }
  .main-content { padding: 90px 16px 100px; }
  .site-header { left: 8px; right: 8px; top: 8px; padding: 10px 16px; }
  .hero h1 { font-size: 24px; }
  .hero-subtitle { font-size: 15px; }
  .compare-grid, .mode-grid { grid-template-columns: 1fr; }
  .step-section { padding: 20px 16px; }
  .scroll-top { bottom: 72px; right: 16px; }
  .phase-header { flex-wrap: wrap; }
  .author-link span { display: none; }
}
@media (max-width: 375px) {
  .header-version { display: none; }
}