@import url('https://fonts.googleapis.com/css2?family=Inter:ital,wght@0,400;0,500;0,600;0,700;1,400&family=JetBrains+Mono:wght@400;500&display=swap');

/* ============================================================
   DESIGN TOKENS
   bchiang7/v4 navy + cyan palette · shadcn card structure
   leerob editorial type scale · magicui radial glow hero
   ============================================================ */

:root {
  /* Dark defaults — bchiang7 navy palette */
  --bg:         #020c1b;
  --bg-surface: #0a192f;
  --bg-card:    #112240;
  --border:     #233554;
  --text:       #ccd6f6;
  --bright:     #e6f1ff;
  --muted:      #8892b0;
  --faint:      #495670;
  --accent:     #64ffda;
  --accent-bg:  rgba(100, 255, 218, 0.07);
  --nav-bg:     rgba(2, 12, 27, 0.88);
  --shadow:     0 4px 28px rgba(0, 0, 0, 0.4);

  /* Shared */
  --r:    8px;
  --ease: cubic-bezier(0.4, 0, 0.2, 1);
  --max:  960px;
  --sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --mono: 'JetBrains Mono', 'Fira Code', 'Courier New', monospace;
}

[data-theme="light"] {
  --bg:         #f8fafc;
  --bg-surface: #f1f5f9;
  --bg-card:    #ffffff;
  --border:     #e2e8f0;
  --text:       #334155;
  --bright:     #0f172a;
  --muted:      #64748b;
  --faint:      #94a3b8;
  --accent:     #0284c7;
  --accent-bg:  rgba(2, 132, 199, 0.07);
  --nav-bg:     rgba(248, 250, 252, 0.88);
  --shadow:     0 2px 16px rgba(0, 0, 0, 0.08);
}

/* ============================================================
   RESET & BASE
   ============================================================ */

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.6;
  color: var(--text);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
  min-height: 100vh;
  transition: background 0.25s var(--ease), color 0.25s var(--ease);
}

a {
  color: var(--accent);
  text-decoration: none;
  transition: color 0.15s;
}
a:hover { text-decoration: underline; }
a:focus-visible {
  outline: 2px dashed var(--accent);
  outline-offset: 3px;
  border-radius: 2px;
}

/* ============================================================
   NAVIGATION
   sticky · blur · bchiang7 100px nav rhythm (scaled to 60px)
   ============================================================ */

.site-nav {
  position: sticky;
  top: 0;
  z-index: 100;
  height: 60px;
  background: var(--nav-bg);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--border);
}

.site-nav__inner {
  max-width: var(--max);
  height: 100%;
  margin: 0 auto;
  padding: 0 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-brand {
  font-size: 14px;
  font-weight: 600;
  color: var(--bright);
  letter-spacing: -0.01em;
  text-decoration: none;
  transition: color 0.15s;
}
.nav-brand:hover { color: var(--accent); text-decoration: none; }
.nav-brand .sep { color: var(--accent); opacity: 0.7; margin: 0 4px; }

.nav-right {
  display: flex;
  align-items: center;
  gap: 16px;
}

.nav-link {
  font-size: 13px;
  font-weight: 500;
  color: var(--muted);
  transition: color 0.15s;
}
.nav-link:hover { color: var(--accent); text-decoration: none; }

.theme-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 34px;
  height: 34px;
  border-radius: 50%;
  border: 1px solid var(--border);
  background: transparent;
  color: var(--muted);
  cursor: pointer;
  transition: color 0.15s, border-color 0.15s, background 0.15s;
  flex-shrink: 0;
}
.theme-btn:hover {
  color: var(--accent);
  border-color: var(--accent);
  background: var(--accent-bg);
}
.theme-btn svg {
  width: 15px;
  height: 15px;
  stroke: currentColor;
  fill: none;
  stroke-width: 1.75;
  stroke-linecap: round;
  stroke-linejoin: round;
  pointer-events: none;
}

.icon-moon { display: block; }
.icon-sun  { display: none;  }
[data-theme="light"] .icon-moon { display: none;  }
[data-theme="light"] .icon-sun  { display: block; }

/* ============================================================
   BREADCRUMB
   monospace — leerob code-page aesthetic
   ============================================================ */

.breadcrumb {
  max-width: var(--max);
  margin: 0 auto;
  padding: 20px 24px 0;
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 12.5px;
  font-family: var(--mono);
  color: var(--muted);
}
.breadcrumb a { color: var(--muted); }
.breadcrumb a:hover { color: var(--accent); text-decoration: none; }
.bc-sep     { color: var(--faint); user-select: none; }
.bc-current { color: var(--text); }

/* ============================================================
   HERO
   magicui radial glow behind title · bchiang7 clamp type
   ============================================================ */

.hero {
  max-width: var(--max);
  margin: 0 auto;
  padding: 64px 24px 52px;
  position: relative;
  overflow: hidden;
}

/* Radial accent glow — top-right quadrant */
.hero::after {
  content: '';
  position: absolute;
  top: -40px;
  right: -60px;
  width: 420px;
  height: 420px;
  background: radial-gradient(circle at center, var(--accent-bg) 0%, transparent 65%);
  pointer-events: none;
  z-index: 0;
}

.hero > * { position: relative; z-index: 1; }

.hero-eyebrow {
  display: block;
  font-family: var(--mono);
  font-size: 11.5px;
  font-weight: 500;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 20px;
}

.hero h1 {
  font-size: clamp(30px, 5vw, 52px);
  font-weight: 700;
  color: var(--bright);
  letter-spacing: -0.03em;
  line-height: 1.1;
  margin-bottom: 20px;
}

.hero-desc {
  font-size: 17px;
  color: var(--text);
  max-width: 560px;
  line-height: 1.65;
}

/* ============================================================
   DIVIDER
   ============================================================ */

.divider {
  max-width: var(--max);
  margin: 0 auto;
  padding: 0 24px;
  border: none;
  border-top: 1px solid var(--border);
}

/* ============================================================
   CARD GRID
   shadcn-ui card proportions · tailwind headlessui spacing
   ============================================================ */

.cards-wrap {
  max-width: var(--max);
  margin: 0 auto;
  padding: 44px 24px 80px;
}

.section-label {
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--faint);
  margin-bottom: 20px;
}

.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(270px, 1fr));
  gap: 14px;
}

.card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--r);
  padding: 24px;
  display: flex;
  flex-direction: column;
  gap: 14px;
  box-shadow: var(--shadow);
  transition: border-color 0.2s var(--ease), transform 0.2s var(--ease);
}
.card:hover {
  border-color: var(--accent);
  transform: translateY(-2px);
}

.card-icon {
  width: 42px;
  height: 42px;
  border-radius: 10px;
  background: var(--accent-bg);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}
.card-icon svg {
  width: 20px;
  height: 20px;
  stroke: var(--accent);
  fill: none;
  stroke-width: 1.75;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.card-body {
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.card-title {
  font-size: 15px;
  font-weight: 600;
  color: var(--bright);
  line-height: 1.3;
}

.card-desc {
  font-size: 13.5px;
  color: var(--muted);
  line-height: 1.55;
  flex: 1;
}

.card-cta {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  font-size: 12.5px;
  font-weight: 600;
  letter-spacing: 0.02em;
  color: var(--accent);
  margin-top: 4px;
  transition: gap 0.15s;
}
.card-cta:hover { gap: 9px; text-decoration: none; }
.card-cta svg {
  width: 12px;
  height: 12px;
  stroke: currentColor;
  fill: none;
  stroke-width: 2.25;
  stroke-linecap: round;
  stroke-linejoin: round;
  transition: transform 0.15s;
}
.card-cta:hover svg { transform: translateX(2px); }

/* ============================================================
   FOOTER
   ============================================================ */

.site-footer {
  border-top: 1px solid var(--border);
  padding: 28px 24px;
}
.site-footer__inner {
  max-width: var(--max);
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 12px;
}

.footer-back {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 13px;
  font-weight: 500;
  color: var(--muted);
  transition: color 0.15s;
}
.footer-back:hover { color: var(--accent); text-decoration: none; }
.footer-back svg {
  width: 13px;
  height: 13px;
  stroke: currentColor;
  fill: none;
  stroke-width: 2;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.footer-text {
  font-size: 12px;
  color: var(--faint);
}

/* ============================================================
   RESPONSIVE
   ============================================================ */

@media (max-width: 640px) {
  .hero        { padding: 44px 20px 36px; }
  .cards-wrap  { padding: 32px 20px 60px; }
  .breadcrumb  { padding: 16px 20px 0; }
  .site-nav__inner { padding: 0 16px; }
  .site-footer { padding: 24px 20px; }
  .nav-brand .brand-sub { display: none; }
}