:root {
  --bg: #0b0c10;
  --bg-elev: #12141a;
  --text: #e6e6eb;
  --muted: #a0a1aa;
  --card: #141722;
  --border: #252838;
  --primary: #6aa3ff;
  --primary-weak: #1b2a4d;
  --accent: #a26bff;
  --ring: #2c3654;
  --success: #35d49a;
  --danger: #ff5a7a;
  --shadow: 0 10px 30px rgba(0,0,0,.25);
}

html[data-theme="light"] {
  --bg: #f7f8fa;
  --bg-elev: #ffffff;
  --text: #121319;
  --muted: #646a73;
  --card: #ffffff;
  --border: #e7e9ee;
  --primary: #2f6bff;
  --primary-weak: #e7efff;
  --accent: #6d42ff;
  --ring: #dfe6ff;
  --shadow: 0 10px 24px rgba(34,57,120,.12);
}

* { box-sizing: border-box; }
html, body { height: 100%; }
body {
  margin: 0;
  font-family: ui-sans-serif, system-ui, -apple-system, Segoe UI, Roboto, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans CJK SC", Arial, sans-serif;
  color: var(--text);
  background: linear-gradient(180deg, var(--bg) 0%, color-mix(in oklab, var(--bg) 85%, var(--card)) 100%);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

a { color: inherit; text-decoration: none; }
img { max-width: 100%; display: block; }
.muted { color: var(--muted); }
.small { font-size: 0.9rem; }
.center { text-align: center; }

.container {
  width: min(1120px, 92vw);
  margin: 0 auto;
}

/* Header */
.site-header {
  position: sticky; top: 0; z-index: 50;
  background: color-mix(in oklab, var(--bg-elev) 92%, transparent);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
}
.nav {
  display: grid; grid-template-columns: 1fr auto 1fr; align-items: center;
  gap: 12px; height: 64px;
}
.brand {
  display: inline-flex; align-items: center; gap: 10px; width: fit-content;
}
.brand-mark {
  display: inline-grid; place-items: center;
  width: 28px; height: 28px; border-radius: 8px;
  background: linear-gradient(135deg, var(--primary), var(--accent));
  color: white; font-weight: 700;
}
.brand-text { font-weight: 700; letter-spacing: .5px; }

.nav-links {
  display: flex; gap: 20px; justify-content: center; align-items: center;
}
.nav-links a { color: var(--muted); }
.nav-links a:hover { color: var(--text); }

.nav-actions { display: flex; gap: 10px; justify-content: end; align-items: center; }
.icon-btn {
  height: 36px; width: 36px; border-radius: 8px;
  border: 1px solid var(--border); background: var(--bg-elev);
  display: grid; place-items: center; cursor: pointer; color: var(--text);
}
.icon-btn:hover { border-color: color-mix(in oklab, var(--border) 80%, var(--text)); }

/* Buttons */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  height: 40px; padding: 0 14px; border-radius: 10px; border: 1px solid var(--border);
  background: var(--bg-elev); color: var(--text); cursor: pointer;
  transition: transform .06s ease, box-shadow .2s ease, border-color .2s ease, background .2s ease;
  box-shadow: none;
}
.btn:hover { transform: translateY(-1px); box-shadow: var(--shadow); }
.btn:active { transform: translateY(0); }

.btn-primary {
  background: linear-gradient(135deg, var(--primary), var(--accent));
  border-color: transparent; color: white;
}
.btn-ghost {
  background: var(--bg-elev); color: var(--text);
}
.btn-sm { height: 34px; padding: 0 12px; border-radius: 8px; }

/* Hero */
.hero {
  position: relative; overflow: clip;
  border-bottom: 1px solid var(--border);
}
.hero-inner {
  padding: 72px 0 48px;
  display: grid; gap: 20px; justify-items: center; text-align: center;
}
.hero-title {
  font-size: clamp(28px, 6vw, 44px);
  line-height: 1.1; margin: 0;
}
.hero-subtitle {
  margin: 6px 0 14px; color: var(--muted); font-size: clamp(14px, 2.2vw, 18px);
}
.hero-actions { display: flex; gap: 12px; }
.hero-showcase {
  margin-top: 16px;
  display: flex; gap: 10px; flex-wrap: wrap; justify-content: center;
}
.chip {
  padding: 6px 10px; border-radius: 999px; font-size: 12px;
  color: white; background: linear-gradient(135deg, var(--primary), var(--accent));
  opacity: .9;
}

.hero-bg {
  position: absolute; inset: 0; pointer-events: none; z-index: -1;
  background:
    radial-gradient(800px 400px at 50% -10%, color-mix(in oklab, var(--primary) 14%, transparent) 0%, transparent 60%),
    radial-gradient(700px 360px at 0% 10%, color-mix(in oklab, var(--accent) 12%, transparent) 0%, transparent 60%),
    radial-gradient(700px 360px at 100% 10%, color-mix(in oklab, var(--success) 10%, transparent) 0%, transparent 60%);
  filter: blur(20px) saturate(120%);
}

/* Sections */
.section { padding: 56px 0; }
.section.alt {
  background: color-mix(in oklab, var(--bg-elev) 96%, var(--bg));
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
}
.section-head { margin-bottom: 20px; }
.section-head h2 {
  margin: 0 0 8px; font-size: clamp(20px, 4vw, 28px);
}
.section-head .muted { margin: 0; }

/* Grid and cards */
.grid { display: grid; gap: 16px; }
.grid.four { grid-template-columns: repeat(4, minmax(0,1fr)); }
.grid.three { grid-template-columns: repeat(3, minmax(0,1fr)); }

.card {
  background: var(--card); border: 1px solid var(--border); border-radius: 14px;
  padding: 16px; box-shadow: none; transition: transform .08s ease, box-shadow .2s ease, border-color .2s ease;
}
.card:hover { transform: translateY(-2px); box-shadow: var(--shadow); }
.feature .icon {
  width: 40px; height: 40px; border-radius: 10px;
  display: grid; place-items: center; font-size: 20px;
  background: color-mix(in oklab, var(--primary-weak) 60%, transparent);
  border: 1px solid var(--border);
  margin-bottom: 8px;
}
.link { color: var(--primary); }
.link:hover { text-decoration: underline; }

/* Demo media placeholders */
.demo-media {
  height: 140px; border-radius: 10px; margin: -6px -6px 10px;
  border: 1px solid var(--border);
}
.gradient-1 { background: linear-gradient(135deg,#2f6bff,#6d42ff); }
.gradient-2 { background: linear-gradient(135deg,#6d42ff,#35d49a); }
.gradient-3 { background: linear-gradient(135deg,#ff5a7a,#2f6bff); }
.actions { display: flex; gap: 10px; flex-wrap: wrap; }

/* Knowledge base */
.kb-search {
  display: grid; gap: 10px; grid-template-columns: 1fr auto; align-items: center;
  margin: 6px 0 16px;
}
.kb-search input[type="search"] {
  height: 40px; border-radius: 10px; border: 1px solid var(--border);
  background: var(--bg-elev); color: var(--text); padding: 0 12px;
  outline: none; box-shadow: inset 0 1px 0 rgba(0,0,0,.05);
}
.tags { display: flex; gap: 8px; flex-wrap: wrap; justify-content: end; }
.tag {
  font-size: 12px; color: var(--text);
  border: 1px solid var(--border); background: var(--bg-elev);
  padding: 6px 10px; border-radius: 999px;
}

/* Subscribe */
.subscribe {
  display: grid; grid-template-columns: 1fr auto; gap: 10px;
  width: min(560px, 100%); margin: 0 auto;
}
.subscribe input[type="email"] {
  height: 44px; border-radius: 12px; border: 1px solid var(--border);
  background: var(--bg-elev); color: var(--text); padding: 0 12px; outline: none;
}

/* Footer */
.site-footer {
  padding: 30px 0; border-top: 1px solid var(--border);
}
.footer-inner {
  display: grid; grid-template-columns: 1fr auto 1fr; align-items: center;
  gap: 12px;
}
.brand-row { display: inline-flex; align-items: center; gap: 10px; }
.footer-links { display: flex; gap: 16px; justify-content: center; }
.footer-links a { color: var(--muted); }
.footer-links a:hover { color: var(--text); }
.copyright { display: flex; gap: 14px; justify-content: end; color: var(--muted); }

/* Responsive */
@media (max-width: 900px) {
  .grid.four { grid-template-columns: repeat(2, minmax(0,1fr)); }
  .grid.three { grid-template-columns: repeat(2, minmax(0,1fr)); }
  .nav { grid-template-columns: auto 1fr auto; }
  .kb-search { grid-template-columns: 1fr; }
  .tags { justify-content: start; }
}
@media (max-width: 600px) {
  .grid.four, .grid.three { grid-template-columns: 1fr; }
  .nav-links { display: none; }
  .hero-inner { padding: 56px 0 36px; }
  .footer-inner { grid-template-columns: 1fr; justify-items: center; gap: 10px; }
  .copyright { justify-content: center; }
}