:root {
  --bg: #0b1020;
  --bg-elev: #121933;
  --surface: #161e3b;
  --border: #243056;
  --text: #e7ecf7;
  --muted: #aab3cf;
  --brand: #5b8cff;
  --brand-2: #7a5bff;
  --accent: #1ed3a4;
  --warn: #ffb454;
  --danger: #ff6b6b;
  --maxw: 1100px;
  --radius: 12px;
  --shadow: 0 10px 30px rgba(0, 0, 0, 0.35);
  --code-bg: #0f1730;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue",
    Arial, "PingFang HK", "Microsoft JhengHei", "Noto Sans CJK TC", sans-serif;
  background: radial-gradient(1200px 600px at 80% -10%, #1a2557 0%, var(--bg) 60%) no-repeat fixed;
  color: var(--text);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--brand); text-decoration: none; }
a:hover { color: #9fb6ff; text-decoration: underline; }

.container {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 0 24px;
}

/* Top navigation */
.nav {
  position: sticky;
  top: 0;
  z-index: 50;
  backdrop-filter: saturate(140%) blur(8px);
  background: rgba(11, 16, 32, 0.78);
  border-bottom: 1px solid var(--border);
}

.nav-inner {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 12px 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  letter-spacing: 0.2px;
  color: var(--text);
}

.brand-logo {
  width: 34px;
  height: 34px;
  border-radius: 8px;
  background: linear-gradient(135deg, var(--brand), var(--brand-2));
  display: grid;
  place-items: center;
  font-size: 16px;
  color: #fff;
  font-weight: 800;
  box-shadow: var(--shadow);
}

.nav-links {
  display: flex;
  gap: 6px;
  flex-wrap: wrap;
}

.nav-links a {
  color: var(--muted);
  padding: 8px 12px;
  border-radius: 8px;
  font-size: 14px;
  font-weight: 500;
}
.nav-links a:hover { color: var(--text); background: var(--surface); text-decoration: none; }
.nav-links a.active { color: var(--text); background: var(--surface); }

/* Hero */
.hero {
  padding: 64px 0 32px;
}
.hero h1 {
  font-size: clamp(28px, 4.2vw, 44px);
  line-height: 1.15;
  margin: 0 0 16px;
  letter-spacing: -0.4px;
}
.hero p.lede {
  font-size: clamp(16px, 1.5vw, 18px);
  color: var(--muted);
  max-width: 780px;
  margin: 0 0 28px;
}
.hero .pill {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: var(--surface);
  border: 1px solid var(--border);
  color: var(--muted);
  padding: 6px 12px;
  border-radius: 999px;
  font-size: 13px;
  margin-bottom: 16px;
}
.hero .pill .dot {
  width: 8px; height: 8px; background: var(--accent); border-radius: 50%;
}

.cta {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 18px;
  border-radius: 10px;
  background: linear-gradient(135deg, var(--brand), var(--brand-2));
  color: #fff !important;
  font-weight: 600;
  border: none;
  cursor: pointer;
  box-shadow: var(--shadow);
}
.cta:hover { filter: brightness(1.07); text-decoration: none; }

.cta-secondary {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 18px;
  border-radius: 10px;
  background: var(--surface);
  border: 1px solid var(--border);
  color: var(--text) !important;
  font-weight: 600;
}
.cta-secondary:hover { background: var(--bg-elev); text-decoration: none; }

/* Section / cards */
section { padding: 32px 0; }

h2 {
  font-size: clamp(22px, 2.4vw, 28px);
  margin: 0 0 18px;
  letter-spacing: -0.2px;
}
h3 {
  font-size: clamp(18px, 1.8vw, 20px);
  margin: 24px 0 8px;
  color: var(--text);
}
h4 {
  font-size: 16px;
  margin: 18px 0 6px;
  color: var(--text);
}

p, li { color: var(--text); }
.muted { color: var(--muted); }

.grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 16px;
}

.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
}
.card h3 { margin-top: 0; }
.card .ico {
  width: 36px; height: 36px;
  border-radius: 8px;
  background: linear-gradient(135deg, rgba(91,140,255,0.2), rgba(122,91,255,0.2));
  border: 1px solid var(--border);
  display: grid; place-items: center;
  margin-bottom: 10px;
  font-size: 18px;
}
.card .more {
  display: inline-block;
  margin-top: 12px;
  font-weight: 600;
}

/* Tables */
.table-wrap { overflow-x: auto; border: 1px solid var(--border); border-radius: var(--radius); }
table {
  width: 100%;
  border-collapse: collapse;
  font-size: 14.5px;
  background: var(--surface);
}
th, td {
  text-align: left;
  padding: 12px 14px;
  border-bottom: 1px solid var(--border);
  vertical-align: top;
}
th {
  background: var(--bg-elev);
  font-weight: 600;
  color: var(--text);
  font-size: 13px;
  letter-spacing: 0.3px;
  text-transform: uppercase;
}
tr:last-child td { border-bottom: none; }

/* Badges */
.badge {
  display: inline-block;
  padding: 2px 9px;
  border-radius: 999px;
  font-size: 12px;
  font-weight: 600;
  border: 1px solid var(--border);
}
.badge-yes { background: rgba(255,107,107,0.12); color: #ff9b9b; border-color: rgba(255,107,107,0.35); }
.badge-no { background: rgba(30,211,164,0.12); color: #6fe6c6; border-color: rgba(30,211,164,0.35); }
.badge-maybe { background: rgba(255,180,84,0.12); color: #ffd49a; border-color: rgba(255,180,84,0.35); }
.badge-info { background: rgba(91,140,255,0.12); color: #b6c8ff; border-color: rgba(91,140,255,0.35); }

/* Callout */
.callout {
  display: flex;
  gap: 12px;
  padding: 14px 16px;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  background: var(--bg-elev);
  margin: 16px 0;
}
.callout.warn { border-color: rgba(255,180,84,0.35); background: rgba(255,180,84,0.08); }
.callout.info { border-color: rgba(91,140,255,0.35); background: rgba(91,140,255,0.06); }
.callout .ico { font-size: 18px; flex-shrink: 0; }

/* Lists */
ul.tidy { padding-left: 20px; }
ul.tidy li { margin-bottom: 6px; }

ol.steps { padding-left: 20px; }
ol.steps li { margin-bottom: 8px; }

/* Code-ish */
code {
  background: var(--code-bg);
  padding: 2px 6px;
  border-radius: 6px;
  font-size: 0.92em;
  border: 1px solid var(--border);
}

/* Decision-tree */
.tree {
  border-left: 3px solid var(--brand);
  padding: 0 0 0 18px;
  margin: 16px 0 16px 6px;
}
.tree .step { margin: 10px 0; }
.tree .q { font-weight: 600; }
.tree .a { color: var(--muted); margin-left: 8px; }

/* Footer */
.footer {
  border-top: 1px solid var(--border);
  margin-top: 48px;
  padding: 28px 0;
  color: var(--muted);
  font-size: 14px;
}
.footer a { color: var(--muted); text-decoration: underline; }

.disclaimer {
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-left: 3px solid var(--warn);
  border-radius: var(--radius);
  padding: 14px 16px;
  font-size: 13.5px;
  color: var(--muted);
  margin: 24px 0;
}

/* Anchor offset for sticky nav */
:target { scroll-margin-top: 80px; }

/* Toc */
.toc {
  position: sticky;
  top: 84px;
  background: var(--surface);
  border: 1px solid var(--border);
  padding: 14px 16px;
  border-radius: var(--radius);
  font-size: 14px;
}
.toc h4 { margin: 0 0 8px; font-size: 13px; text-transform: uppercase; color: var(--muted); letter-spacing: 0.6px; }
.toc a { display: block; padding: 4px 0; color: var(--muted); }
.toc a:hover { color: var(--text); text-decoration: none; }

.layout-toc {
  display: grid;
  grid-template-columns: 1fr;
  gap: 24px;
}
@media (min-width: 960px) {
  .layout-toc { grid-template-columns: 240px 1fr; }
}

/* Misc */
hr { border: none; border-top: 1px solid var(--border); margin: 28px 0; }