/* ============================================================
   Awesome AI Native — visual system
   ============================================================ */
:root {
  --bg: #07080c;
  --bg-soft: #0d0f16;
  --card: #11141d;
  --card-hover: #161a25;
  --border: #1f2430;
  --border-soft: #171b25;
  --text: #eef1f6;
  --text-dim: #98a1b2;
  --text-faint: #626b7d;
  --accent: #7c93ff;
  --accent-2: #4be3c0;
  --accent-soft: rgba(124, 147, 255, 0.14);
  --cat: var(--accent); /* per-section accent, set inline */
  --radius: 16px;
  --radius-sm: 10px;
  --shadow: 0 1px 2px rgba(0, 0, 0, 0.5), 0 14px 40px rgba(0, 0, 0, 0.35);
  --shadow-glow: 0 0 0 1px color-mix(in srgb, var(--cat) 40%, transparent), 0 12px 36px color-mix(in srgb, var(--cat) 18%, transparent);
  --maxw: 1240px;
  --sans: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  --display: "Space Grotesk", "Inter", -apple-system, BlinkMacSystemFont, sans-serif;
  --ease: cubic-bezier(0.22, 1, 0.36, 1);
}

html[data-theme="light"] {
  --bg: #fbfcfe;
  --bg-soft: #ffffff;
  --card: #ffffff;
  --card-hover: #f6f8fc;
  --border: #e6eaf2;
  --border-soft: #eef1f7;
  --text: #131722;
  --text-dim: #525b6b;
  --text-faint: #8b93a4;
  --accent: #4f63d2;
  --accent-2: #0fa088;
  --accent-soft: rgba(79, 99, 210, 0.1);
  --shadow: 0 1px 2px rgba(20, 30, 60, 0.05), 0 14px 40px rgba(20, 30, 60, 0.08);
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } * { animation: none !important; transition: none !important; } }

body {
  margin: 0;
  font-family: var(--sans);
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  overflow-x: hidden;
}

a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: none; }

.wrap { max-width: var(--maxw); margin: 0 auto; padding: 0 28px; }

::selection { background: color-mix(in srgb, var(--accent) 40%, transparent); }

/* ---------- Aurora background ---------- */
.aurora {
  position: fixed;
  inset: 0;
  z-index: -1;
  overflow: hidden;
  pointer-events: none;
}
.aurora::before, .aurora::after {
  content: "";
  position: absolute;
  width: 60vw; height: 60vw;
  border-radius: 50%;
  filter: blur(90px);
  opacity: 0.5;
}
.aurora::before {
  top: -18vw; left: -10vw;
  background: radial-gradient(circle at 30% 30%, #5b6cff 0%, transparent 60%);
  animation: drift1 26s var(--ease) infinite alternate;
}
.aurora::after {
  top: -8vw; right: -14vw;
  background: radial-gradient(circle at 70% 30%, #19c8a8 0%, transparent 60%);
  animation: drift2 32s var(--ease) infinite alternate;
}
html[data-theme="light"] .aurora::before { opacity: 0.28; }
html[data-theme="light"] .aurora::after { opacity: 0.22; }
@keyframes drift1 { to { transform: translate(14vw, 8vw) scale(1.15); } }
@keyframes drift2 { to { transform: translate(-10vw, 10vw) scale(1.2); } }

/* ---------- Header ---------- */
header.site {
  position: sticky; top: 0; z-index: 60;
  background: color-mix(in srgb, var(--bg) 80%, transparent);
  backdrop-filter: saturate(160%) blur(14px);
  border-bottom: 1px solid var(--border-soft);
}
.nav { display: flex; align-items: center; gap: 14px; height: 62px; }
.brand { display: flex; align-items: center; gap: 10px; font-family: var(--display); font-weight: 700; font-size: 17px; color: var(--text); letter-spacing: -0.01em; }
.brand:hover { text-decoration: none; }
.brand svg { width: 26px; height: 26px; display: block; }
.nav .spacer { flex: 1; }

.icon-btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 6px;
  border: 1px solid var(--border); background: var(--card); color: var(--text-dim);
  height: 38px; min-width: 38px; padding: 0 11px; border-radius: var(--radius-sm);
  cursor: pointer; font-size: 14px; font-weight: 600; transition: all 0.18s var(--ease);
}
.icon-btn:hover { color: var(--text); border-color: color-mix(in srgb, var(--accent) 50%, var(--border)); background: var(--card-hover); transform: translateY(-1px); }
.lang-toggle { display: inline-flex; border: 1px solid var(--border); border-radius: var(--radius-sm); overflow: hidden; height: 38px; }
.lang-toggle button { border: 0; background: var(--card); color: var(--text-dim); padding: 0 13px; cursor: pointer; font-size: 13px; font-weight: 700; font-family: var(--sans); transition: all 0.18s var(--ease); }
.lang-toggle button:hover { color: var(--text); }
.lang-toggle button.active { background: linear-gradient(135deg, var(--accent), color-mix(in srgb, var(--accent) 60%, var(--accent-2))); color: #fff; }

/* ---------- Hero ---------- */
.hero { padding: 72px 0 40px; position: relative; }
.eyebrow {
  display: inline-flex; align-items: center; gap: 8px;
  font-size: 12.5px; font-weight: 700; letter-spacing: 0.08em; text-transform: uppercase;
  color: var(--accent-2); border: 1px solid var(--border); background: var(--card);
  padding: 6px 13px; border-radius: 999px; margin-bottom: 22px;
}
.eyebrow .pulse { width: 7px; height: 7px; border-radius: 50%; background: var(--accent-2); box-shadow: 0 0 0 0 var(--accent-2); animation: pulse 2.4s infinite; }
@keyframes pulse { 0% { box-shadow: 0 0 0 0 color-mix(in srgb, var(--accent-2) 70%, transparent); } 70% { box-shadow: 0 0 0 8px transparent; } 100% { box-shadow: 0 0 0 0 transparent; } }

.hero h1 { font-family: var(--display); font-size: clamp(40px, 7vw, 76px); line-height: 1.0; letter-spacing: -0.035em; margin: 0 0 20px; font-weight: 700; }
.hero h1 .grad { background: linear-gradient(110deg, var(--accent) 10%, var(--accent-2) 90%); -webkit-background-clip: text; background-clip: text; -webkit-text-fill-color: transparent; }
.hero .lede { font-size: clamp(17px, 2.3vw, 22px); color: var(--text-dim); max-width: 680px; margin: 0 0 30px; }

.cta-row { display: flex; flex-wrap: wrap; gap: 12px; }
.btn { display: inline-flex; align-items: center; gap: 8px; padding: 12px 20px; border-radius: 11px; font-weight: 650; font-size: 14.5px; border: 1px solid var(--border); cursor: pointer; transition: all 0.18s var(--ease); }
.btn.primary { background: linear-gradient(135deg, var(--accent), color-mix(in srgb, var(--accent) 55%, var(--accent-2))); color: #fff; border-color: transparent; box-shadow: 0 8px 24px color-mix(in srgb, var(--accent) 30%, transparent); }
.btn.primary:hover { transform: translateY(-2px); box-shadow: 0 12px 30px color-mix(in srgb, var(--accent) 40%, transparent); text-decoration: none; }
.btn.ghost { background: var(--card); color: var(--text); }
.btn.ghost:hover { border-color: color-mix(in srgb, var(--accent) 50%, var(--border)); transform: translateY(-2px); text-decoration: none; }

.stats { display: flex; gap: 36px; margin-top: 42px; flex-wrap: wrap; }
.stat .num { font-family: var(--display); font-size: 34px; font-weight: 700; letter-spacing: -0.02em; line-height: 1; background: linear-gradient(135deg, var(--text), var(--text-dim)); -webkit-background-clip: text; background-clip: text; -webkit-text-fill-color: transparent; }
.stat .lbl { font-size: 12.5px; color: var(--text-faint); text-transform: uppercase; letter-spacing: 0.07em; margin-top: 7px; }

/* ---------- What is + comparison ---------- */
.explain { display: grid; grid-template-columns: 1fr 1.25fr; gap: 40px; align-items: start; margin: 64px 0 8px; }
.explain h2 { font-family: var(--display); font-size: 28px; letter-spacing: -0.02em; margin: 0 0 14px; font-weight: 700; }
.explain .intro { font-size: 16px; color: var(--text-dim); }
.explain .intro strong { color: var(--text); font-weight: 650; }
.explain .analogy { margin-top: 16px; padding: 14px 16px; border-left: 3px solid var(--accent-2); background: var(--card); border-radius: 0 var(--radius-sm) var(--radius-sm) 0; font-size: 14.5px; color: var(--text-dim); }

.compare { border: 1px solid var(--border); border-radius: var(--radius); overflow: hidden; background: var(--bg-soft); box-shadow: var(--shadow); }
.compare table { width: 100%; border-collapse: collapse; font-size: 14.5px; }
.compare th, .compare td { padding: 14px 18px; text-align: left; border-bottom: 1px solid var(--border-soft); vertical-align: top; }
.compare tr:last-child td { border-bottom: 0; }
.compare thead th { font-size: 11.5px; text-transform: uppercase; letter-spacing: 0.07em; color: var(--text-faint); background: var(--card); font-weight: 700; }
.compare thead th:last-child { color: var(--accent); }
.compare td:first-child, .compare th:first-child { font-weight: 650; color: var(--text-dim); width: 120px; }
.compare tbody tr { transition: background 0.18s var(--ease); }
.compare tbody tr:hover { background: var(--card); }
.compare td:last-child { color: var(--text); }

/* ---------- Controls (sticky search) ---------- */
.controls { position: sticky; top: 62px; z-index: 50; background: color-mix(in srgb, var(--bg) 88%, transparent); backdrop-filter: blur(10px); padding: 16px 0; border-bottom: 1px solid var(--border-soft); margin-top: 56px; }
.search-wrap { position: relative; }
.search {
  width: 100%; padding: 14px 96px 14px 46px; border-radius: 12px;
  border: 1px solid var(--border); background: var(--card); color: var(--text);
  font-size: 15px; font-family: var(--sans);
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='18' height='18' viewBox='0 0 24 24' fill='none' stroke='%2398a1b2' stroke-width='2' stroke-linecap='round'%3E%3Ccircle cx='11' cy='11' r='8'/%3E%3Cpath d='m21 21-4.3-4.3'/%3E%3C/svg%3E");
  background-repeat: no-repeat; background-position: 16px center;
  transition: border-color 0.18s var(--ease), box-shadow 0.18s var(--ease);
}
.search::placeholder { color: var(--text-faint); }
.search:focus { outline: none; border-color: var(--accent); box-shadow: 0 0 0 4px var(--accent-soft); }
.search-kbd { position: absolute; right: 14px; top: 50%; transform: translateY(-50%); display: flex; gap: 5px; pointer-events: none; }
.search-kbd kbd { font-family: var(--sans); font-size: 11px; color: var(--text-faint); background: var(--bg-soft); border: 1px solid var(--border); border-radius: 6px; padding: 2px 7px; }
.chips { display: none; gap: 8px; margin-top: 12px; overflow-x: auto; padding-bottom: 2px; -webkit-overflow-scrolling: touch; scrollbar-width: none; }
.chips::-webkit-scrollbar { display: none; }
.chip { border: 1px solid var(--border); background: var(--card); color: var(--text-dim); padding: 7px 13px; border-radius: 999px; font-size: 13px; font-weight: 600; cursor: pointer; white-space: nowrap; transition: all 0.16s var(--ease); }
.chip.active { background: var(--accent-soft); color: var(--accent); border-color: color-mix(in srgb, var(--accent) 50%, var(--border)); }

/* ---------- Layout: sidebar + content ---------- */
.layout { display: grid; grid-template-columns: 232px 1fr; gap: 44px; padding: 36px 0 80px; align-items: start; }
.sidebar { position: sticky; top: 150px; align-self: start; }
.sidebar nav { display: flex; flex-direction: column; gap: 2px; }
.side-group { font-size: 10.5px; font-weight: 700; letter-spacing: 0.11em; text-transform: uppercase; color: var(--text-faint); padding: 16px 11px 6px; }
.side-group:first-child { padding-top: 0; }
.side-link { display: flex; align-items: center; gap: 10px; padding: 8px 11px; border-radius: var(--radius-sm); color: var(--text-dim); font-size: 13.5px; font-weight: 550; cursor: pointer; transition: all 0.16s var(--ease); border: 1px solid transparent; }
.side-link .se { font-size: 15px; width: 20px; text-align: center; }
.side-link .sn { flex: 1; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.side-link .sc { font-size: 11.5px; color: var(--text-faint); font-variant-numeric: tabular-nums; }
.side-link:hover { color: var(--text); background: var(--card); text-decoration: none; }
.side-link.active { color: var(--text); background: var(--card); border-color: var(--border); box-shadow: inset 3px 0 0 var(--cat); }
.side-link.active .se { filter: drop-shadow(0 0 6px color-mix(in srgb, var(--cat) 70%, transparent)); }

/* ---------- Category sections + cards ---------- */
main#cats { min-width: 0; }
.group-head { display: flex; align-items: center; gap: 16px; margin: 44px 0 28px; }
.group-head:first-child { margin-top: 4px; }
.group-head .gtitle { font-family: var(--display); font-size: 13px; font-weight: 700; letter-spacing: 0.16em; text-transform: uppercase; color: var(--text-dim); white-space: nowrap; }
.group-head::after { content: ""; flex: 1; height: 1px; background: linear-gradient(90deg, var(--border), transparent); }
.cat { margin: 0 0 52px; scroll-margin-top: 160px; }
.cat-head { display: flex; align-items: center; gap: 12px; margin-bottom: 5px; }
.cat-badge { display: inline-flex; align-items: center; justify-content: center; width: 38px; height: 38px; border-radius: 11px; font-size: 19px; background: color-mix(in srgb, var(--cat) 16%, transparent); border: 1px solid color-mix(in srgb, var(--cat) 30%, transparent); }
.cat-head h2 { font-family: var(--display); font-size: 23px; letter-spacing: -0.02em; margin: 0; font-weight: 700; }
.cat-head .count { margin-left: auto; font-size: 12px; color: var(--text-faint); font-weight: 650; background: var(--card); border: 1px solid var(--border); padding: 3px 10px; border-radius: 999px; }
.cat-desc { color: var(--text-dim); margin: 0 0 20px; font-size: 14.5px; padding-left: 50px; }

.grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(290px, 1fr)); gap: 14px; }
.card {
  position: relative; display: flex; flex-direction: column; gap: 7px;
  border: 1px solid var(--border); background: var(--card); border-radius: var(--radius);
  padding: 18px 18px 17px; overflow: hidden; cursor: pointer;
  transition: transform 0.2s var(--ease), border-color 0.2s var(--ease), box-shadow 0.2s var(--ease), background 0.2s var(--ease);
}
.card::before { content: ""; position: absolute; left: 0; top: 0; bottom: 0; width: 3px; background: var(--cat); opacity: 0; transition: opacity 0.2s var(--ease); }
.card:hover { transform: translateY(-3px); background: var(--card-hover); border-color: color-mix(in srgb, var(--cat) 45%, var(--border)); box-shadow: var(--shadow-glow); }
.card:hover::before { opacity: 1; }
.card .title { display: block; font-weight: 700; font-size: 15.5px; color: var(--text); letter-spacing: -0.01em; line-height: 1.35; padding-right: 18px; }
a.title:hover { text-decoration: none; }
.card:hover .title { color: var(--cat); }
.card .author { font-size: 12px; color: color-mix(in srgb, var(--cat) 75%, var(--text-dim)); font-weight: 650; }
.card .note { font-size: 13.5px; color: var(--text-dim); margin: 2px 0 0; }
.card .arrow { position: absolute; top: 15px; right: 15px; color: var(--text-faint); opacity: 0; transition: all 0.2s var(--ease); }
.card:hover .arrow { opacity: 1; transform: translate(2px, -2px); color: var(--cat); }

/* highlight search matches */
mark { background: color-mix(in srgb, var(--accent-2) 35%, transparent); color: var(--text); border-radius: 3px; padding: 0 2px; }

/* reveal on scroll */
.reveal { opacity: 0; transform: translateY(14px); transition: opacity 0.5s var(--ease), transform 0.5s var(--ease); }
.reveal.in { opacity: 1; transform: none; }

.empty { text-align: center; padding: 80px 0; color: var(--text-faint); font-size: 15px; }

/* ---------- Back to top ---------- */
.totop { position: fixed; right: 24px; bottom: 24px; z-index: 70; width: 44px; height: 44px; border-radius: 50%; border: 1px solid var(--border); background: var(--card); color: var(--text-dim); cursor: pointer; font-size: 18px; display: flex; align-items: center; justify-content: center; opacity: 0; pointer-events: none; transform: translateY(10px); transition: all 0.25s var(--ease); box-shadow: var(--shadow); }
.totop.show { opacity: 1; pointer-events: auto; transform: none; }
.totop:hover { color: var(--text); border-color: var(--accent); transform: translateY(-2px); }

/* ---------- Footer ---------- */
footer.site { border-top: 1px solid var(--border-soft); padding: 40px 0; color: var(--text-faint); font-size: 14px; }
.foot-row { display: flex; flex-wrap: wrap; gap: 10px 22px; align-items: center; justify-content: space-between; }
footer.site a { color: var(--text-dim); }
footer.site a:hover { color: var(--accent); }

/* ---------- Responsive ---------- */
@media (max-width: 960px) {
  .layout { grid-template-columns: 1fr; gap: 0; }
  .sidebar { display: none; }
  .chips { display: flex; }
  .explain { grid-template-columns: 1fr; gap: 26px; }
}
@media (max-width: 640px) {
  .wrap { padding: 0 18px; }
  .hero { padding: 48px 0 24px; }
  .stats { gap: 26px; }
  .compare { overflow-x: auto; }
  .cat-desc { padding-left: 0; }
  .controls { top: 62px; }
}