/* ============================================================
   无限AI · 主题（参考 Kouri AI 的极简黑白骨架 + 樱色单点强调）
   - 底色近乎纯黑，靠排版/留白撑质感，不靠大面积渐变
   - 强调色只用一种：#ff5c93（樱），出现在主按钮、链接、选中态
   - 圆角 10px，字体 Sora + 国产无衬线中文
   只改 :root 就能换肤
   ============================================================ */

:root {
  --bg: #0a0a0b;
  --bg-soft: #0e0e10;
  --surface: #111113;
  --surface-2: #16161a;
  --line: #202025;
  --line-strong: #2c2c33;
  --text: #fafafa;
  --muted: #a1a1aa;
  --muted-2: #71717a;

  --sakura: #ff5c93;
  --sakura-soft: #ffa8c5;
  --violet: #b388ff;
  --success: #4ade80;

  --radius: 10px;
  --radius-sm: 8px;
  --max: 1140px;
  --font: "Sora", "HarmonyOS Sans SC", "MiSans", "OPPO Sans", "PingFang SC", "Microsoft YaHei", system-ui, sans-serif;
  --mono: "JetBrains Mono", "Fira Code", "SF Mono", Menlo, Consolas, monospace;
}

* { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }

body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--font);
  font-size: 15.5px;
  line-height: 1.7;
  letter-spacing: -.005em;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

a { color: inherit; text-decoration: none; }
img { max-width: 100%; display: block; }
button { font-family: inherit; cursor: pointer; }

.wrap { width: min(var(--max), calc(100% - 48px)); margin: 0 auto; }

/* ---------- 背景 ---------- */
.glow {
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 0;
  background:
    radial-gradient(760px 380px at 16% -12%, rgba(255, 92, 147, .10), transparent 62%),
    radial-gradient(640px 360px at 92% -6%, rgba(179, 136, 255, .07), transparent 64%);
}

.grid-bg {
  position: fixed;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  background-image:
    linear-gradient(rgba(255, 255, 255, .022) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255, 255, 255, .022) 1px, transparent 1px);
  background-size: 64px 64px;
  mask-image: radial-gradient(circle at 50% 0%, #000 0%, transparent 68%);
}

#petals {
  position: fixed;
  inset: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  z-index: 1;
  opacity: .45;
}

main, header, footer { position: relative; z-index: 2; }

/* ---------- 头部 ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  backdrop-filter: blur(16px) saturate(140%);
  background: rgba(10, 10, 11, .76);
  border-bottom: 1px solid var(--line);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
  gap: 24px;
}

.brand { display: flex; align-items: center; gap: 9px; font-weight: 600; letter-spacing: -.02em; font-size: 15px; }

.brand-mark {
  width: 28px; height: 28px;
  border-radius: 8px;
  background: var(--sakura);
  display: grid; place-items: center;
  font-size: 15px; font-weight: 700; color: #fff;
}

.nav { display: flex; align-items: center; gap: 2px; }
.nav a {
  padding: 7px 12px;
  border-radius: 7px;
  color: var(--muted);
  font-size: 13.5px;
  transition: color .16s, background .16s;
}
.nav a:hover { color: var(--text); background: var(--surface-2); }

.header-cta { display: flex; align-items: center; gap: 8px; }

.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  padding: 9px 16px;
  border-radius: var(--radius-sm);
  border: 1px solid transparent;
  font-size: 13.5px; font-weight: 600; letter-spacing: -.01em;
  transition: background .18s, border-color .18s, color .18s, transform .14s;
  white-space: nowrap;
}
.btn:hover { transform: translateY(-1px); }
.btn-primary { background: var(--sakura); color: #fff; }
.btn-primary:hover { background: #ff4a86; }
.btn-ghost { border-color: var(--line-strong); color: var(--text); background: transparent; }
.btn-ghost:hover { background: var(--surface-2); border-color: #3a3a44; }
.btn-sm { padding: 7px 13px; font-size: 13px; }

.menu-toggle {
  display: none;
  width: 38px; height: 38px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--line-strong);
  background: transparent;
  color: var(--text);
  font-size: 17px;
}

/* ---------- Hero ---------- */
.hero { padding: 104px 0 76px; position: relative; overflow: hidden; }

.hero::after {
  content: "❀";
  position: absolute;
  right: 2%;
  top: 6%;
  font-size: clamp(160px, 24vw, 300px);
  line-height: 1;
  color: rgba(255, 168, 197, .045);
  pointer-events: none;
  z-index: -1;
}

.badge {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 5px 12px 5px 10px;
  border-radius: 999px;
  border: 1px solid var(--line-strong);
  background: var(--surface);
  font-size: 12.5px; color: var(--muted);
  margin-bottom: 26px;
}
.dot { width: 6px; height: 6px; border-radius: 50%; background: var(--success); box-shadow: 0 0 0 3px rgba(74, 222, 128, .14); }

.hero h1 {
  font-size: clamp(38px, 5.2vw, 64px);
  line-height: 1.04;
  letter-spacing: -.045em;
  font-weight: 700;
  max-width: 16ch;
}
.hero h1 .grad { color: var(--sakura); }

.hero p.lead {
  margin-top: 22px;
  max-width: 600px;
  color: var(--muted);
  font-size: 16px;
  line-height: 1.8;
}
.hero-actions { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 34px; }

.stats {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  margin-top: 64px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
}
.stat { padding: 22px; border-right: 1px solid var(--line); background: var(--bg-soft); }
.stat:last-child { border-right: 0; }
.stat b { display: block; font-size: 24px; font-weight: 700; letter-spacing: -.03em; }
.stat span { color: var(--muted-2); font-size: 12.5px; }

/* ---------- 区块 ---------- */
section { padding: 96px 0; }
.section-head { margin-bottom: 40px; max-width: 720px; }
.section-head h2 { font-size: clamp(26px, 3vw, 36px); letter-spacing: -.035em; line-height: 1.15; font-weight: 700; }
.section-head p { color: var(--muted); margin-top: 12px; font-size: 15px; }

.eyebrow {
  font-family: var(--mono);
  font-size: 11.5px;
  letter-spacing: .18em;
  text-transform: uppercase;
  color: var(--muted-2);
  margin-bottom: 14px;
}
.eyebrow::before { content: "❀ "; color: var(--sakura); letter-spacing: 0; }

/* ---------- 模型 ---------- */
.filters { display: flex; flex-wrap: wrap; gap: 6px; margin-bottom: 26px; }

.chip {
  padding: 6px 13px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--line);
  background: transparent;
  color: var(--muted);
  font-size: 13px;
  transition: all .16s;
}
.chip:hover { color: var(--text); border-color: var(--line-strong); }
.chip.active {
  color: var(--text);
  background: var(--surface-2);
  border-color: var(--line-strong);
  font-weight: 600;
}
.chip.active::before {
  content: "";
  display: inline-block;
  width: 5px; height: 5px;
  border-radius: 50%;
  background: var(--sakura);
  margin-right: 7px;
  vertical-align: middle;
}

.model-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(230px, 1fr)); gap: 10px; }

.model-card {
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  background: var(--surface);
  padding: 15px 15px 13px;
  transition: border-color .18s, background .18s, transform .16s;
}
.model-card:hover { border-color: var(--line-strong); background: var(--surface-2); transform: translateY(-1px); }
.model-card .name { font-weight: 600; font-size: 14px; letter-spacing: -.01em; word-break: break-word; }
.model-card .meta { display: flex; gap: 8px; align-items: center; margin-top: 9px; color: var(--muted-2); font-size: 11.5px; }

.tag { font-size: 10.5px; padding: 1px 7px; border-radius: 5px; border: 1px solid var(--line-strong); color: var(--muted); }
.tag.chat { color: var(--sakura-soft); border-color: rgba(255, 92, 147, .35); }
.tag.reason { color: #cbb3ff; border-color: rgba(179, 136, 255, .3); }
.tag.code { color: #9be8bd; border-color: rgba(74, 222, 128, .28); }

/* ---------- 价格 ---------- */
.billing-toggle {
  display: inline-flex; align-items: center; gap: 2px;
  padding: 3px; border: 1px solid var(--line); border-radius: var(--radius-sm);
  margin-bottom: 28px; background: var(--surface);
}
.billing-toggle button {
  border: 0; background: transparent; color: var(--muted);
  padding: 6px 14px; border-radius: 6px; font-size: 13px;
}
.billing-toggle button.active { background: var(--surface-2); color: var(--text); font-weight: 600; }

.plans { display: grid; grid-template-columns: repeat(3, 1fr); gap: 12px; align-items: stretch; }

.plan {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--bg-soft);
  padding: 26px 24px;
  display: flex; flex-direction: column; gap: 18px;
  position: relative;
  transition: border-color .18s;
}
.plan:hover { border-color: var(--line-strong); }
.plan.featured { border-color: rgba(255, 92, 147, .55); background: linear-gradient(180deg, rgba(255, 92, 147, .07), rgba(255, 255, 255, .008)); }
.plan .plan-name { font-size: 13px; color: var(--muted); letter-spacing: .02em; }
.plan .price { font-size: 36px; font-weight: 700; letter-spacing: -.04em; line-height: 1; margin-top: 6px; }
.plan .price small { font-size: 13px; color: var(--muted-2); font-weight: 400; letter-spacing: 0; }
.plan ul { list-style: none; display: grid; gap: 8px; color: var(--muted); font-size: 13.5px; }
.plan ul li::before { content: "·"; color: var(--sakura); margin-right: 8px; font-weight: 700; }
.plan .btn { margin-top: auto; }
.plan .ribbon {
  position: absolute; top: 16px; right: 18px;
  font-size: 10.5px; font-weight: 600; letter-spacing: .04em;
  padding: 3px 8px; border-radius: 999px;
  border: 1px solid rgba(255, 92, 147, .45);
  color: var(--sakura);
  background: rgba(255, 92, 147, .08);
}

/* ---------- 代码 ---------- */
.code-box { border: 1px solid var(--line); border-radius: var(--radius); background: #08080a; overflow: hidden; }
.code-tabs { display: flex; gap: 2px; padding: 8px 8px 0; border-bottom: 1px solid var(--line); flex-wrap: wrap; }
.code-tabs button {
  border: 0; background: transparent; color: var(--muted-2);
  padding: 7px 13px; border-radius: 6px 6px 0 0; font-size: 12.5px;
  font-family: var(--mono);
}
.code-tabs button.active { color: var(--text); background: var(--surface); }
.code-body { position: relative; }
.code-body pre {
  margin: 0; padding: 22px; overflow-x: auto;
  font-family: var(--mono); font-size: 12.5px; line-height: 1.8;
  color: #d9d9e3; tab-size: 2;
}
.copy-btn {
  position: absolute; top: 12px; right: 12px;
  border: 1px solid var(--line-strong); background: var(--surface);
  color: var(--muted); font-size: 11.5px; padding: 4px 10px; border-radius: 6px;
}
.copy-btn:hover { color: var(--text); }

.inline-code {
  font-family: var(--mono); font-size: .9em;
  background: var(--surface-2); color: var(--sakura-soft);
  padding: 1px 6px; border-radius: 5px;
}

/* ---------- 特性 ---------- */
.features { display: grid; grid-template-columns: repeat(3, 1fr); gap: 12px; }
.feature {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 24px 22px;
  background: var(--bg-soft);
  transition: border-color .18s;
}
.feature:hover { border-color: var(--line-strong); }
.feature .ico {
  width: 34px; height: 34px; border-radius: var(--radius-sm);
  display: grid; place-items: center;
  border: 1px solid var(--line-strong);
  background: var(--surface);
  margin-bottom: 16px; font-size: 15px; color: var(--sakura-soft);
}
.feature h3 { font-size: 14.5px; margin-bottom: 8px; font-weight: 600; letter-spacing: -.01em; }
.feature p { color: var(--muted); font-size: 13.5px; line-height: 1.72; }

/* ---------- FAQ ---------- */
.faq { display: grid; gap: 8px; max-width: 820px; }
details.item {
  border: 1px solid var(--line); border-radius: var(--radius-sm);
  background: var(--bg-soft); padding: 17px 20px;
  transition: border-color .16s;
}
details.item:hover { border-color: var(--line-strong); }
details.item summary {
  cursor: pointer; font-weight: 600; font-size: 14px; list-style: none;
  display: flex; justify-content: space-between; gap: 16px;
}
details.item summary::-webkit-details-marker { display: none; }
details.item summary::after {
  content: "+"; color: var(--muted-2);
  font-size: 16px; font-family: var(--mono); line-height: 1;
}
details.item[open] summary::after { content: "−"; }
details.item p { color: var(--muted); font-size: 13.5px; margin-top: 12px; }

/* ---------- CTA ---------- */
.cta-band {
  border: 1px solid var(--line-strong);
  border-radius: var(--radius);
  padding: 44px 40px;
  background: var(--bg-soft);
  display: flex; align-items: center; justify-content: space-between; gap: 24px; flex-wrap: wrap;
  position: relative;
  overflow: hidden;
}
.cta-band::after {
  content: "❀";
  position: absolute; right: 26px; bottom: -30px;
  font-size: 130px; color: rgba(255, 168, 197, .07); line-height: 1;
  pointer-events: none;
}
.cta-band h2 { font-size: clamp(22px, 2.6vw, 30px); letter-spacing: -.03em; font-weight: 700; }
.cta-band p { color: var(--muted); margin-top: 8px; font-size: 14px; }

/* ---------- 页脚 ---------- */
.site-footer { border-top: 1px solid var(--line); padding: 40px 0 56px; margin-top: 40px; }
.footer-inner { display: flex; justify-content: space-between; gap: 28px; flex-wrap: wrap; color: var(--muted-2); font-size: 12.5px; }
.footer-links { display: flex; gap: 18px; flex-wrap: wrap; }
.footer-links a:hover { color: var(--text); }

/* ---------- 动画 ---------- */
.reveal { opacity: 0; transform: translateY(10px); transition: opacity .5s ease, transform .5s ease; }
.reveal.in { opacity: 1; transform: none; }

/* ---------- 响应式 ---------- */
@media (max-width: 900px) {
  .nav { display: none; }
  .menu-toggle { display: grid; place-items: center; }
  .nav.open {
    display: flex; position: absolute; top: 64px; left: 0; right: 0;
    flex-direction: column; align-items: stretch; gap: 2px;
    padding: 10px 24px 18px;
    background: rgba(10, 10, 11, .99);
    border-bottom: 1px solid var(--line);
  }
  .stats { grid-template-columns: repeat(2, 1fr); }
  .stat:nth-child(2) { border-right: 0; }
  .stat:nth-child(1), .stat:nth-child(2) { border-bottom: 1px solid var(--line); }
  .plans, .features { grid-template-columns: 1fr; }
  .hero { padding: 64px 0 48px; }
  section { padding: 64px 0; }
  .cta-band { padding: 30px 24px; }
}

@media (max-width: 520px) {
  .wrap { width: calc(100% - 32px); }
  .header-cta .btn-ghost { display: none; }
  .stat b { font-size: 21px; }
}

@media (prefers-reduced-motion: reduce) {
  #petals { display: none; }
  .reveal { opacity: 1; transform: none; transition: none; }
  html { scroll-behavior: auto; }
}