:root {
  --bg: #f7f6f3;
  --raise: #fffefc;
  --card: #ffffff;
  --text: #161513;
  --secondary: #63605a;
  --tertiary: #9c978f;
  --hairline: #e7e3db;
  --accent: #3b5570;
  --accent-soft: #eaeef3;
  --shadow: 0 1px 2px rgba(28, 27, 25, .04), 0 12px 32px -12px rgba(28, 27, 25, .12);
  --bezel: #2a2c30;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #101113;
    --raise: #17191b;
    --card: #1d1f22;
    --text: #f2f3f5;
    --secondary: #9aa0a8;
    --tertiary: #6e747c;
    --hairline: #2a2d31;
    --accent: #93aecb;
    --accent-soft: #1b2530;
    --shadow: 0 12px 40px -16px rgba(0, 0, 0, .6);
    --bezel: #08090a;
  }
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 16px/1.7 -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
        "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  -webkit-font-smoothing: antialiased;
  -webkit-text-size-adjust: 100%;
}

.wrap { max-width: 1040px; margin: 0 auto; padding: 0 24px; }
.narrow { max-width: 720px; }

/* ── 顶栏 ───────────────────────────────── */
.top {
  position: sticky; top: 0; z-index: 20;
  background: color-mix(in srgb, var(--bg) 82%, transparent);
  backdrop-filter: saturate(180%) blur(20px);
  -webkit-backdrop-filter: saturate(180%) blur(20px);
  border-bottom: 0.5px solid var(--hairline);
}
.top .wrap {
  display: flex; align-items: center; justify-content: space-between;
  gap: 20px; height: 60px;
}
.brand { display: flex; align-items: center; gap: 11px; text-decoration: none; color: inherit; }
.brand img { width: 30px; height: 30px; border-radius: 7.5px; display: block; }
.brand b { font-weight: 550; font-size: 15px; letter-spacing: -0.1px; }
.brand i { font-style: normal; color: var(--tertiary); font-size: 13px; margin-left: 3px; }

nav { display: flex; align-items: center; gap: 4px; }
nav a {
  color: var(--secondary); text-decoration: none; font-size: 14px;
  padding: 6px 11px; border-radius: 7px;
}
nav a:hover { color: var(--text); background: var(--card); }
nav a[aria-current] { color: var(--text); }

#lang {
  margin-left: 6px;
  border: 0.5px solid var(--hairline); background: var(--card); color: var(--secondary);
  border-radius: 7px; padding: 6px 11px; font: inherit; font-size: 13px; cursor: pointer;
}
#lang:hover { color: var(--text); border-color: var(--tertiary); }

/* ── 首屏 ───────────────────────────────── */
.hero { padding: 76px 0 0; text-align: center; }
.hero-icon {
  width: 76px; height: 76px; border-radius: 18px;
  box-shadow: var(--shadow); margin: 0 auto 26px; display: block;
}
.hero h1 {
  font-size: clamp(31px, 5.2vw, 50px);
  line-height: 1.14; font-weight: 560; letter-spacing: -1.1px;
  margin: 0 auto 18px; max-width: 15em;
}
.hero .lead {
  color: var(--secondary); font-size: clamp(15px, 1.9vw, 18px);
  max-width: 32em; margin: 0 auto; line-height: 1.65;
}

/* ── 手机外框 ───────────────────────────── */
.phone {
  background: var(--bezel);
  border-radius: 34px;
  padding: 7px;
  box-shadow: var(--shadow);
  width: 250px; flex: none;
}
.phone img { display: block; width: 100%; border-radius: 27px; }
.phone.lg { width: 286px; border-radius: 38px; padding: 8px; }
.phone.lg img { border-radius: 31px; }

.hero-stage {
  margin-top: 52px;
  display: flex; justify-content: center; align-items: flex-end; gap: 26px;
  padding-bottom: 8px;
}
.hero-stage .side { transform: translateY(22px) scale(.9); opacity: .82; }
@media (max-width: 720px) { .hero-stage .side { display: none; } }

/* ── 分节 ───────────────────────────────── */
section { padding: 84px 0; }
.rule { border-top: 0.5px solid var(--hairline); }

.eyebrow {
  font-size: 12px; letter-spacing: .09em; text-transform: uppercase;
  color: var(--accent); font-weight: 550; margin: 0 0 12px;
}
h2 { font-size: clamp(23px, 3vw, 31px); line-height: 1.25; font-weight: 550; letter-spacing: -0.6px; margin: 0 0 14px; }
h3 { font-size: 16px; font-weight: 550; margin: 0 0 6px; letter-spacing: -0.1px; }
p { margin: 0 0 14px; }
.muted { color: var(--secondary); }

/* 图文交替 */
.feature {
  display: grid; grid-template-columns: 1fr 250px; gap: 64px; align-items: center;
  padding: 62px 0;
}
.feature + .feature { border-top: 0.5px solid var(--hairline); }
.feature.flip { grid-template-columns: 250px 1fr; }
.feature.flip .copy { order: 2; }
.feature .shot { display: flex; justify-content: center; }
@media (max-width: 820px) {
  .feature, .feature.flip { grid-template-columns: 1fr; gap: 36px; }
  .feature.flip .copy { order: 0; }
  .feature .phone { margin: 0 auto; }
}

/* 数字强调 */
.figure {
  font-size: clamp(30px, 4.4vw, 42px); font-weight: 560; letter-spacing: -1px;
  line-height: 1.1; margin: 0 0 8px;
}
.figure.neg { color: #b5563f; }
@media (prefers-color-scheme: dark) { .figure.neg { color: #e88b7d; } }

/* ── 卡片 / 网格 ────────────────────────── */
.grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(230px, 1fr)); gap: 14px; }
.card {
  background: var(--card); border: 0.5px solid var(--hairline);
  border-radius: 14px; padding: 20px 22px;
}
.card p:last-child { margin-bottom: 0; }

.band {
  background: var(--accent-soft);
  border-radius: 18px; padding: 40px clamp(22px, 4vw, 48px);
}
.band h2 { margin-bottom: 10px; }

/* ── 文档页 ─────────────────────────────── */
.doc { padding: 56px 0 96px; }
.doc h1 { font-size: clamp(27px, 3.6vw, 36px); font-weight: 550; letter-spacing: -0.8px; margin: 0 0 8px; }
.doc h2 { font-size: 18px; margin: 40px 0 10px; letter-spacing: -0.2px; }
.doc h3 { margin-top: 26px; }
.doc p, .doc li { color: var(--text); }
.doc .meta { color: var(--tertiary); font-size: 13.5px; margin: 0 0 30px; }
.doc ul { padding-left: 20px; }
.doc li { margin: 7px 0; }

.summary {
  background: var(--raise); border: 0.5px solid var(--hairline);
  border-left: 2px solid var(--accent);
  border-radius: 0 14px 14px 0; padding: 20px 24px; margin: 0 0 8px;
}
.key { border-left: 2px solid var(--accent); padding-left: 18px; margin: 22px 0; color: var(--secondary); }

table { width: 100%; border-collapse: collapse; font-size: 14.5px; margin: 18px 0; }
th, td { text-align: left; padding: 11px 10px; border-bottom: 0.5px solid var(--hairline); vertical-align: top; }
th { color: var(--tertiary); font-weight: 500; font-size: 13px; }

code {
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace; font-size: .88em;
  background: var(--bg); border: 0.5px solid var(--hairline); border-radius: 5px; padding: 1px 6px;
}

a { color: var(--accent); text-underline-offset: 3px; }

.mail {
  display: inline-block; margin-top: 4px;
  font-size: clamp(17px, 2.4vw, 22px); font-weight: 500; letter-spacing: -0.3px;
  text-decoration: none;
}
.mail:hover { text-decoration: underline; }

footer {
  border-top: 0.5px solid var(--hairline);
  padding: 30px 0 56px; color: var(--tertiary); font-size: 13.5px;
  display: flex; justify-content: space-between; gap: 16px; flex-wrap: wrap;
}
footer a { color: var(--tertiary); text-decoration: none; }
footer a:hover { color: var(--text); }

/* ── 双语显隐 ───────────────────────────── */
[lang] { display: none; }
html[data-lang="zh"] [lang="zh"] { display: revert; }
html[data-lang="en"] [lang="en"] { display: revert; }
html[data-lang="zh"] nav a[lang="zh"],
html[data-lang="en"] nav a[lang="en"] { display: block; }