/* ============================================================================
   starryid.com — 主站
   ----------------------------------------------------------------------------
   产品介绍页。和 app / docs 共用设计变量，但排布是营销页节奏：
   大标题 → 特性卡片 → 三步流程 → 开发者卖点 → FAQ → 页脚
   ========================================================================== */

:root {
  --bg: #05060b;
  --surface: #0c0f18;
  --surface-2: #141824;
  --surface-3: #1c2130;

  --line: #1c2130;
  --line-strong: #2a3145;

  --text: #f0f2f7;
  --muted: #a0a8bd;
  --faint: #6e7689;

  --accent: #9db4ff;
  --accent-deep: #4a5fd0;
  --accent-text: #b8c9ff;
  --on-accent: #060a18;

  --ok: #4ade80;
  --warn: #f2c14e;

  --font: "Geist", -apple-system, BlinkMacSystemFont, "Segoe UI", system-ui, sans-serif;
  --mono: "Geist Mono", ui-monospace, "SF Mono", Menlo, Consolas, monospace;
  --font-brand: "Space Grotesk", var(--font);
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background-color: var(--bg);
  background-image:
    radial-gradient(1100px 700px at 50% -14%, rgba(110, 140, 255, 0.14), transparent 64%),
    radial-gradient(820px 520px at 82% 8%, rgba(150, 125, 255, 0.08), transparent 62%);
  background-attachment: fixed;
  color: var(--text);
  font-family: var(--font);
  font-size: 15px;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

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

/* 星空点缀 */
body::before {
  content: "";
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 0;
  background-image:
    radial-gradient(1.4px 1.4px at 12% 18%, rgba(200, 215, 255, 0.55), transparent),
    radial-gradient(1.2px 1.2px at 78% 12%, rgba(200, 215, 255, 0.42), transparent),
    radial-gradient(1.6px 1.6px at 34% 62%, rgba(190, 210, 255, 0.34), transparent),
    radial-gradient(1.1px 1.1px at 64% 78%, rgba(200, 215, 255, 0.38), transparent),
    radial-gradient(1.3px 1.3px at 89% 45%, rgba(190, 210, 255, 0.30), transparent),
    radial-gradient(1.2px 1.2px at 22% 88%, rgba(200, 215, 255, 0.26), transparent);
}

.page { position: relative; z-index: 1; }

/* ---------------------------------------------------------------------------
   顶栏
   ------------------------------------------------------------------------- */
.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 16px 28px;
  max-width: 1120px;
  margin: 0 auto;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  color: var(--text);
  font-family: var(--font-brand);
  font-size: 17px;
  font-weight: 500;
  letter-spacing: 0.005em;
}
.brand:hover { text-decoration: none; }
.brand svg { color: var(--accent); }

.topbar-right { display: flex; align-items: center; gap: 20px; font-size: 13.5px; }
.topbar-right a { color: var(--muted); }
.topbar-right a:hover { color: var(--text); text-decoration: none; }

/* ---------------------------------------------------------------------------
   按钮
   ------------------------------------------------------------------------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 7px;
  font: inherit;
  font-size: 13.5px;
  font-weight: 500;
  line-height: 1;
  padding: 11px 20px;
  border-radius: 9999px;
  border: 1px solid var(--line-strong);
  background: var(--surface-2);
  color: var(--text);
  cursor: pointer;
  transition: background .15s, border-color .15s;
}
.btn:hover { background: var(--surface-3); border-color: #35405a; text-decoration: none; }

.btn.primary {
  background: var(--accent);
  border-color: var(--accent);
  color: var(--on-accent);
  font-weight: 600;
}
.btn.primary:hover { background: #b3c5ff; border-color: #b3c5ff; }

.btn.lg { padding: 13px 26px; font-size: 14.5px; }

/* ---------------------------------------------------------------------------
   Hero
   ------------------------------------------------------------------------- */
.hero {
  max-width: 820px;
  margin: 0 auto;
  padding: 84px 28px 96px;
  text-align: center;
}

.hero h1 {
  font-size: clamp(34px, 6vw, 54px);
  font-weight: 600;
  line-height: 1.16;
  letter-spacing: -0.03em;
  margin: 0 0 22px;
}
.hero h1 em {
  font-style: normal;
  background: linear-gradient(100deg, #b8c9ff 10%, #9db4ff 45%, #c4b0ff 90%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.hero p {
  font-size: 17px;
  line-height: 1.7;
  color: var(--muted);
  margin: 0 auto 34px;
  max-width: 60ch;
}

.hero-cta { display: flex; gap: 12px; justify-content: center; flex-wrap: wrap; }

.hero-note {
  margin-top: 22px;
  font-size: 12.5px;
  color: var(--faint);
}

/* ---------------------------------------------------------------------------
   通用区块
   ------------------------------------------------------------------------- */
.wrap { max-width: 1040px; margin: 0 auto; padding: 0 28px; }

.section { padding: 72px 0; }
.section.tight { padding: 52px 0; }

.section h2 {
  font-size: 26px;
  font-weight: 600;
  letter-spacing: -0.02em;
  margin: 0 0 10px;
  text-align: center;
}
.section > .wrap > p.sub {
  text-align: center;
  color: var(--muted);
  margin: 0 0 44px;
  font-size: 15px;
}

/* 特性卡片 */
.cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 16px;
}

.card {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 26px 24px;
}
.card .ico {
  width: 38px;
  height: 38px;
  border-radius: 10px;
  display: grid;
  place-items: center;
  background: var(--surface-3);
  border: 1px solid var(--line-strong);
  color: var(--accent);
  margin-bottom: 16px;
}
.card h3 {
  font-size: 15.5px;
  font-weight: 600;
  margin: 0 0 8px;
}
.card p {
  margin: 0;
  font-size: 13.5px;
  line-height: 1.65;
  color: var(--muted);
}

/* 三步 */
.steps3 {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 16px;
  counter-reset: s;
}
.step {
  position: relative;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 26px 24px 24px;
  counter-increment: s;
}
.step::before {
  content: counter(s, decimal-leading-zero);
  position: absolute;
  top: 20px;
  right: 22px;
  font-family: var(--mono);
  font-size: 12px;
  color: var(--faint);
  letter-spacing: 0.05em;
}
.step h3 { font-size: 15px; font-weight: 600; margin: 0 0 8px; }
.step p { margin: 0; font-size: 13.5px; color: var(--muted); line-height: 1.65; }

code {
  font-family: var(--mono);
  font-size: 12.5px;
  background: var(--surface-3);
  padding: 1.5px 6px;
  border-radius: 4px;
  color: var(--accent-text);
}

/* 开发者区块 */
.dev {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 16px;
  padding: 40px 36px;
  display: grid;
  grid-template-columns: 1.1fr 1fr;
  gap: 44px;
  align-items: center;
}
.dev h2 {
  text-align: left;
  margin-bottom: 12px;
  font-size: 24px;
}
.dev .lead { color: var(--muted); margin: 0 0 20px; font-size: 14.5px; }
.dev ul { margin: 0 0 26px; padding-left: 20px; }
.dev li { margin-bottom: 10px; color: #d3d9e6; font-size: 14px; line-height: 1.6; }

.dev pre {
  margin: 0;
  background: #080a11;
  border: 1px solid var(--line);
  border-radius: 11px;
  padding: 18px 20px;
  overflow-x: auto;
  font-family: var(--mono);
  font-size: 12.5px;
  line-height: 1.7;
  color: #cdd6e8;
}
.dev pre .k { color: #9db4ff; }
.dev pre .s { color: #8fdfb0; }
.dev pre .c { color: #5a6478; }

/* FAQ */
.faq { max-width: 720px; margin: 0 auto; }
.faq details {
  border-bottom: 1px solid var(--line);
  padding: 18px 0;
}
.faq summary {
  cursor: pointer;
  font-size: 15px;
  font-weight: 500;
  list-style: none;
  display: flex;
  justify-content: space-between;
  gap: 16px;
  align-items: center;
}
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after {
  content: "+";
  font-family: var(--mono);
  color: var(--faint);
  font-size: 16px;
  flex: none;
  transition: transform .15s;
}
.faq details[open] summary::after { content: "−"; }
.faq p {
  margin: 12px 0 0;
  color: var(--muted);
  font-size: 14px;
  line-height: 1.7;
}

/* 页脚 */
.footer {
  border-top: 1px solid var(--line);
  margin-top: 40px;
  padding: 40px 28px 56px;
}
.footer-inner {
  max-width: 1040px;
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  gap: 32px;
  flex-wrap: wrap;
}
.footer-brand { color: var(--muted); font-size: 13.5px; }
.footer-brand .tag { margin-top: 6px; color: var(--faint); font-size: 12.5px; }
.footer-links { display: flex; gap: 32px; flex-wrap: wrap; }
.footer-col { display: flex; flex-direction: column; gap: 8px; font-size: 13px; }
.footer-col .h { color: var(--faint); font-size: 11.5px; text-transform: uppercase; letter-spacing: 0.06em; margin-bottom: 2px; }
.footer-col a { color: var(--muted); }
.footer-col a:hover { color: var(--text); }

/* 语言切换 */
.lang-switch {
  display: inline-flex;
  border: 1px solid var(--line-strong);
  border-radius: 9999px;
  overflow: hidden;
}
.lang-switch button {
  font: inherit;
  font-size: 12px;
  padding: 4px 10px;
  background: transparent;
  border: 0;
  color: var(--faint);
  cursor: pointer;
}
.lang-switch button:hover { color: var(--text); }
.lang-switch button.active { background: var(--surface-3); color: var(--text); }

@media (max-width: 820px) {
  .dev { grid-template-columns: 1fr; gap: 28px; padding: 30px 24px; }
  .hero { padding: 56px 20px 64px; }
  .section { padding: 52px 0; }
  .topbar { padding: 14px 20px; }
  .wrap { padding: 0 20px; }
}