:root {
  --bg: #080A0E;
  --surface: #0E1117;
  --border: rgba(255,255,255,0.07);
  --accent: #00E5FF;
  --accent2: #FF6B35;
  --accent3: #A8FF3E;
  --text: #E8EAF0;
  --muted: #6B7280;
}

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

body {
  background: var(--bg);
  color: var(--text);
  font-family: 'Syne', sans-serif;
  overflow-x: hidden;
  cursor: none;
}

body::before {
  content: '';
  position: fixed; inset: 0;
  background-image:
    linear-gradient(rgba(0,229,255,0.03) 1px, transparent 1px),
    linear-gradient(90deg, rgba(0,229,255,0.03) 1px, transparent 1px);
  background-size: 60px 60px;
  pointer-events: none; z-index: 0;
}

.cursor {
  width: 12px; height: 12px;
  background: var(--accent);
  border-radius: 50%;
  position: fixed; pointer-events: none; z-index: 9999;
  transition: transform 0.15s ease, background 0.2s;
  mix-blend-mode: difference;
}
.cursor-ring {
  width: 36px; height: 36px;
  border: 1.5px solid var(--accent);
  border-radius: 50%;
  position: fixed; pointer-events: none; z-index: 9998;
  transition: left 0.08s ease, top 0.08s ease;
  opacity: 0.5; mix-blend-mode: difference;
}

/* ── Top Navigation ── */
.topnav {
  position: fixed; top: 0; left: 0; right: 0;
  display: flex; align-items: center; gap: 24px;
  padding: 16px 4vw;
  background: rgba(8,10,14,0.92);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  z-index: 100;
}
.nav-brand {
  font-family: 'DM Serif Display', serif;
  font-size: 1.2rem; color: var(--accent);
  text-decoration: none; margin-right: auto;
}
.nav-brand em { color: var(--text); }
.nav-days { display: flex; gap: 4px; }
.nav-day {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.6rem; font-weight: 700;
  letter-spacing: 0.1em; text-transform: uppercase;
  color: var(--muted); text-decoration: none;
  padding: 6px 12px; border: 1px solid var(--border);
  transition: all 0.2s;
}
.nav-day:hover, .nav-day.active {
  color: var(--c, var(--accent));
  border-color: var(--c, var(--accent));
}

/* ── Hero Mini ── */
.hero-mini {
  position: relative; z-index: 1;
  padding: 140px 10vw 80px;
  overflow: hidden;
}
.hero-bg-circle {
  position: absolute; width: 700px; height: 700px;
  background: radial-gradient(circle, rgba(0,229,255,0.08) 0%, transparent 70%);
  right: -200px; top: 50%; transform: translateY(-50%);
  pointer-events: none;
}
.badge {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.7rem; font-weight: 700;
  letter-spacing: 0.2em; text-transform: uppercase;
  color: var(--accent); border: 1px solid var(--accent);
  padding: 6px 16px; display: inline-block;
  margin-bottom: 32px; animation: fadeUp 0.6s ease both;
}
.hero-mini h1 {
  font-family: 'DM Serif Display', serif;
  font-size: clamp(2.5rem, 5vw, 4.5rem);
  line-height: 1; margin-bottom: 20px;
  animation: fadeUp 0.7s ease 0.1s both;
}
.hero-mini h1 em { font-style: italic; color: var(--accent); }
.hero-mini p {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.9rem; color: var(--muted);
  max-width: 560px; line-height: 1.7;
  animation: fadeUp 0.7s ease 0.2s both;
}

/* ── Hub Grid ── */
.hub-grid { position: relative; z-index: 1; padding: 0 6vw 120px; }
.section-label {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.65rem; letter-spacing: 0.25em;
  text-transform: uppercase; color: var(--muted);
  margin-bottom: 48px; padding-left: 4vw;
  display: flex; align-items: center; gap: 16px;
}
.section-label::before { content: ''; width: 40px; height: 1px; background: var(--muted); }
.days-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px,1fr));
  gap: 20px;
}
.hub-card {
  border: 1px solid var(--border);
  padding: 40px 32px;
  position: relative; overflow: hidden;
  text-decoration: none; color: var(--text);
  transition: border-color 0.3s, background 0.3s;
}
.hub-card:hover {
  border-color: var(--c);
  background: rgba(255,255,255,0.02);
}
.hub-num {
  font-family: 'DM Serif Display', serif;
  font-size: 4rem; color: var(--c);
  opacity: 0.15; position: absolute;
  top: 16px; right: 24px; line-height: 1;
}
.hub-tag {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.6rem; font-weight: 700;
  letter-spacing: 0.2em; text-transform: uppercase;
  margin-bottom: 16px;
}
.hub-title {
  font-family: 'DM Serif Display', serif;
  font-size: 1.5rem; line-height: 1.2;
  margin-bottom: 20px;
}
.hub-meta {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.7rem; color: var(--muted);
}

/* ── Day Content Page ── */
.day-hero {
  position: relative; z-index: 1;
  padding: 140px 10vw 60px;
}
.day-hero-number {
  font-family: 'DM Serif Display', serif;
  font-size: clamp(6rem,12vw,10rem);
  line-height: 0.85; opacity: 0.08;
  position: absolute; right: 6vw; top: 100px;
  pointer-events: none;
}
.day-hero-tag {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.65rem; font-weight: 700;
  letter-spacing: 0.2em; text-transform: uppercase;
  margin-bottom: 16px;
}
.day-hero h1 {
  font-family: 'DM Serif Display', serif;
  font-size: clamp(2.2rem,4.5vw,4rem);
  line-height: 1.05; margin-bottom: 16px;
}
.day-hero h1 em { font-style: italic; }
.day-hero-desc {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.85rem; color: var(--muted);
  max-width: 600px; line-height: 1.7;
}

/* ── Topic Section ── */
.topic-section {
  position: relative; z-index: 1;
  padding: 80px 8vw;
  border-top: 1px solid var(--border);
}
.topic-header {
  display: flex; align-items: flex-start;
  gap: 24px; margin-bottom: 48px;
}
.topic-index {
  font-family: 'DM Serif Display', serif;
  font-size: 3rem; line-height: 1;
  opacity: 0.25; flex-shrink: 0;
}
.topic-info h2 {
  font-family: 'DM Serif Display', serif;
  font-size: 2rem; line-height: 1.1;
  margin-bottom: 12px;
}
.topic-info .lead {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.8rem; color: var(--muted);
  line-height: 1.7; max-width: 640px;
}

/* ── Content blocks ── */
.content-block {
  margin-bottom: 48px;
}
.content-block h3 {
  font-family: 'Syne', sans-serif;
  font-weight: 800; font-size: 1.1rem;
  margin-bottom: 16px;
  padding-left: 16px;
  border-left: 3px solid var(--c, var(--accent));
}
.content-block p, .content-block li {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.78rem; color: var(--muted);
  line-height: 1.8;
}
.content-block ul {
  list-style: none; padding-left: 0;
}
.content-block li { padding: 6px 0 6px 20px; position: relative; }
.content-block li::before {
  content: '→';
  position: absolute; left: 0;
  color: var(--c, var(--accent));
  font-size: 0.7rem;
}

/* ── Diagram container ── */
.diagram-wrap {
  background: var(--surface);
  border: 1px solid var(--border);
  padding: 32px;
  margin: 32px 0;
  overflow-x: auto;
}
.diagram-wrap svg {
  width: 100%; height: auto;
  max-height: 400px;
}
.diagram-caption {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.65rem; color: var(--muted);
  text-align: center; margin-top: 16px;
  letter-spacing: 0.1em; text-transform: uppercase;
}

/* ── Code block ── */
.code-block {
  background: var(--surface);
  border: 1px solid var(--border);
  padding: 24px; margin: 24px 0;
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.75rem; line-height: 1.8;
  color: var(--muted); overflow-x: auto;
  white-space: pre;
}
.code-block .kw { color: var(--accent); }
.code-block .str { color: #A8FF3E; }
.code-block .cmt { color: #444; }
.code-block .num { color: #FF6B35; }

/* ── Callout ── */
.callout {
  border: 1px solid var(--border);
  border-left: 3px solid var(--c, var(--accent));
  padding: 24px 28px;
  margin: 32px 0;
  background: rgba(255,255,255,0.015);
}
.callout-title {
  font-family: 'Syne', sans-serif;
  font-weight: 800; font-size: 0.85rem;
  margin-bottom: 8px;
}
.callout-text {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.72rem; color: var(--muted);
  line-height: 1.7;
}

/* ── Comparison table ── */
.compare-table {
  width: 100%; border-collapse: collapse;
  margin: 24px 0;
}
.compare-table th, .compare-table td {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.72rem;
  padding: 12px 16px;
  border: 1px solid var(--border);
  text-align: left;
}
.compare-table th {
  background: var(--surface);
  color: var(--c, var(--accent));
  font-weight: 700; letter-spacing: 0.05em;
  text-transform: uppercase; font-size: 0.65rem;
}
.compare-table td { color: var(--muted); }

/* ── Day navigation ── */
.day-nav {
  position: relative; z-index: 1;
  display: flex; justify-content: space-between;
  padding: 40px 8vw;
  border-top: 1px solid var(--border);
}
.day-nav a {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.75rem; color: var(--muted);
  text-decoration: none; padding: 12px 24px;
  border: 1px solid var(--border);
  transition: all 0.2s;
}
.day-nav a:hover { color: var(--text); border-color: rgba(255,255,255,0.3); }

/* ── Footer ── */
.footer {
  position: relative; z-index: 1;
  padding: 48px 10vw;
  border-top: 1px solid var(--border);
  display: flex; justify-content: space-between;
  align-items: center; flex-wrap: wrap; gap: 24px;
}
.footer-brand {
  font-family: 'DM Serif Display', serif;
  font-size: 1.5rem; color: var(--accent);
}
.footer-text {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.65rem; color: var(--muted);
}

@keyframes fadeUp {
  from { opacity: 0; transform: translateY(24px); }
  to { opacity: 1; transform: translateY(0); }
}

@media (max-width: 768px) {
  .topnav { flex-wrap: wrap; }
  .nav-days { flex-wrap: wrap; }
  .hero-mini, .day-hero { padding: 120px 6vw 60px; }
  .topic-section { padding: 60px 5vw; }
  .topic-header { flex-direction: column; }
  .days-grid { grid-template-columns: 1fr; }
}