/* 两地扫码 · 官网
   浅色版式站：暖白底、唯一强调色、大标题、极简卡片、深色演示段。 */

:root {
  --bg: #fbfaf7;
  --bg-alt: #edf2ec;
  --ink: #101413;
  --ink-2: #4e5a55;
  --ink-3: #8a948e;
  --line: #e4e7e1;
  --line-2: #d7dcd5;
  --brand: #0f3b2e;
  --brand-2: #14634c;
  --mint: #46e0ae;
  --mint-deep: #12a57c;
  --mint-soft: #e8f8f1;
  --dark: #0c1310;
  --dark-2: #141d18;
  --radius: 18px;
  --shell: 1200px;
  --shadow: 0 1px 2px rgba(16, 20, 19, .04), 0 12px 32px -18px rgba(16, 20, 19, .18);
  --sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "HarmonyOS Sans SC", "Microsoft YaHei", Roboto, sans-serif;
  --mono: ui-monospace, SFMono-Regular, "Cascadia Mono", Consolas, Menlo, monospace;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

img { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }
h1, h2, h3, h4 { margin: 0; letter-spacing: -.035em; text-wrap: balance; }
p { margin: 0; }

.wrap { max-width: var(--shell); margin: 0 auto; padding: 0 clamp(20px, 5vw, 64px); }

/* ---------------- 导航 ---------------- */

.nav {
  position: fixed; inset: 0 0 auto; z-index: 20;
  display: flex; align-items: center; gap: 28px;
  height: 64px; padding: 0 clamp(20px, 5vw, 64px);
  border-bottom: 1px solid transparent;
  transition: background .25s, border-color .25s, backdrop-filter .25s;
}
.nav.stuck {
  background: rgba(251, 250, 247, .82);
  border-bottom-color: var(--line);
  -webkit-backdrop-filter: saturate(160%) blur(14px);
  backdrop-filter: saturate(160%) blur(14px);
}
.brand { display: flex; align-items: center; gap: 9px; font-weight: 700; letter-spacing: -.02em; }
.brand img { width: 26px; height: 26px; }
.brand span { font-size: 16.5px; }
.brand em { font-style: normal; font-size: 10px; letter-spacing: .16em; color: var(--ink-3); font-weight: 600; }

.links { display: flex; align-items: center; gap: 26px; margin-left: auto; }
.links a { font-size: 14px; color: var(--ink-2); transition: color .18s; }
.links a:hover { color: var(--ink); }

.navcta { display: flex; align-items: center; gap: 10px; }

/* ---------------- 按钮 ---------------- */

.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  padding: 14px 24px; border-radius: 999px;
  font-size: 15px; font-weight: 600; letter-spacing: -.01em;
  background: var(--brand); color: #fff;
  border: 1px solid var(--brand);
  transition: transform .16s ease, box-shadow .2s ease, background .2s;
  box-shadow: 0 10px 24px -14px rgba(15, 59, 46, .8);
}
.btn:hover { transform: translateY(-1px); box-shadow: 0 14px 30px -14px rgba(15, 59, 46, .75); }
.btn.sm { padding: 9px 18px; font-size: 13.5px; box-shadow: none; }
.btn.ghost {
  background: #fff; color: var(--ink); border-color: var(--line-2); box-shadow: none;
}
.btn.ghost:hover { border-color: var(--ink-3); }
.btn.mint { background: var(--mint); color: #06301f; border-color: var(--mint); }
.btn svg { width: 17px; height: 17px; }

/* ---------------- Hero ---------------- */

.hero {
  position: relative; overflow: hidden;
  padding: clamp(124px, 14vw, 176px) 0 clamp(56px, 7vw, 88px);
  background:
    radial-gradient(120% 90% at 50% -20%, #eefaf3 0%, rgba(251, 250, 247, 0) 58%),
    linear-gradient(#f7faf6, var(--bg));
}
.hero::before {
  content: ""; position: absolute; inset: 0;
  background-image:
    linear-gradient(to right, #e8ece5 1px, transparent 1px),
    linear-gradient(to bottom, #e8ece5 1px, transparent 1px);
  background-size: 72px 72px;
  opacity: .5;
  mask-image: radial-gradient(120% 80% at 50% 8%, #000 20%, transparent 72%);
  -webkit-mask-image: radial-gradient(120% 80% at 50% 8%, #000 20%, transparent 72%);
}
.hero .wrap { position: relative; text-align: center; }

.hero h1 {
  font-size: clamp(40px, 6vw, 84px);
  line-height: 1.07; font-weight: 800; letter-spacing: -.04em;
}
.hero h1 em { font-style: normal; color: var(--mint-deep); }
.hero h1 .mint { color: var(--brand); }

.lede {
  max-width: 660px; margin: 26px auto 0;
  font-size: clamp(15.5px, 1.6vw, 17.5px); line-height: 1.8; color: var(--ink-2);
  text-wrap: pretty;
}
.lede b { color: var(--brand); font-weight: 700; }
.lede .pain { display: block; font-size: .92em; color: var(--ink-3); }
.actions { display: flex; flex-wrap: wrap; gap: 12px; justify-content: center; margin-top: 32px; }

/* 数字行 */
.stats {
  display: flex; flex-wrap: wrap; justify-content: center; gap: clamp(28px, 6vw, 72px);
  margin-top: clamp(42px, 5.6vw, 66px); padding-top: 24px;
  border-top: 1px solid var(--line);
}
.stats div { text-align: left; min-width: 96px; }
.stats dt { font-size: 12.5px; color: var(--ink-3); letter-spacing: .04em; }
.stats dd {
  margin: 4px 0 0; font-size: clamp(26px, 3.4vw, 36px); font-weight: 750; letter-spacing: -.03em;
  font-variant-numeric: tabular-nums;
}
.stats dd small { font-size: .46em; font-weight: 600; color: var(--ink-3); margin-left: 3px; letter-spacing: 0; }

/* ---------------- 通用章节 ---------------- */

.section { padding: clamp(66px, 8.6vw, 118px) 0; }
.section.dark { background: var(--dark); color: #eef4f1; }

.head { max-width: 720px; margin: 0 auto clamp(34px, 4.6vw, 56px); text-align: center; }
.head h2 { font-size: clamp(27px, 3.3vw, 40px); line-height: 1.2; font-weight: 780; }
.head h2 em { font-style: normal; color: var(--mint-deep); }
.section.dark .head h2 em { color: var(--mint); }
.head p { margin-top: 14px; color: var(--ink-2); font-size: 15.5px; text-wrap: pretty; }
.section.dark .head p { color: #a7b6b0; }

/* ---------------- 流程链：两段六步 ----------------
   一条链路拆两段：发起（人 → 人）与执行（中继 → 学习通）。
   段内是一条贯穿的细轨，圆点压在轨上，步骤号挂在圆点左上角；
   段与段之间用虚线切一刀，终点（回传）反色收尾。 */

/* ---------------- 流程：两行三列 ----------------
   六个动作只留图标、标题、一句描述。等宽三列保证两行对齐，
   不画连接线、不挂步骤号：链路本身不复杂，界面也不该复杂。 */

.flow {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: clamp(30px, 4.2vw, 54px) clamp(16px, 2.6vw, 40px);
  margin: 0; padding: 0; list-style: none;
}
.flow li { display: grid; justify-items: center; text-align: center; }

.flow .dot {
  width: 58px; height: 58px; border-radius: 18px;
  display: grid; place-items: center;
  background: var(--mint-soft); color: var(--mint-deep);
  border: 1px solid #d5f0e4;
  transition: transform .2s ease, border-color .2s ease, box-shadow .2s ease;
}
.flow .dot svg { width: 25px; height: 25px; }
.flow h3 { margin: 15px 0 6px; font-size: 16.5px; font-weight: 700; }
.flow p { font-size: 13.6px; color: var(--ink-2); max-width: 220px; text-wrap: balance; }

.flow li:hover .dot { transform: translateY(-2px); border-color: #b6e7d4; box-shadow: 0 14px 24px -18px rgba(18, 165, 124, .8); }

/* 终点：回传成功，反色收尾 */
.flow li.end .dot { background: var(--brand); border-color: var(--brand); color: var(--mint); }
.flow li.end h3 { color: var(--brand); }

/* ---------------- 演示（深色段） ---------------- */

.phones {
  display: grid; grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: clamp(20px, 3.4vw, 44px); justify-items: center;
  max-width: 780px; margin: 0 auto;
}
.phone {
  width: 100%; max-width: 340px; padding: 10px;
  background: #0f1714; border: 1px solid #22322b; border-radius: 26px;
  box-shadow: 0 30px 60px -40px rgba(0, 0, 0, .95);
}
.phone img { display: block; width: 100%; height: auto; border-radius: 18px; }
.phone b { display: block; margin: 12px 4px 4px; font-size: 13px; font-weight: 600; color: #cfdcd6; }

.darknote { margin-top: clamp(28px, 4vw, 44px); text-align: center; font-size: 13.5px; color: #8fa39b; text-wrap: balance; }

/* ---------------- 上手 ---------------- */

/* ---------------- 页脚 ---------------- */

.foot { background: var(--dark); color: #9fb2ab; padding: clamp(44px, 5vw, 64px) 0 40px; }
.foot .wrap { display: flex; flex-wrap: wrap; align-items: center; gap: 18px; justify-content: space-between; }
.foot .brand { color: #eef4f1; }
.foot p { font-size: 13.6px; line-height: 1.9; max-width: 620px; color: #93a89f; letter-spacing: .01em; }
.foot nav { display: flex; gap: 18px; font-size: 13px; }
.foot nav a:hover { color: var(--mint); }

/* ---------------- 入场 ---------------- */

.reveal { opacity: 0; transform: translateY(14px); transition: opacity .5s ease, transform .5s ease; }
.reveal.in { opacity: 1; transform: none; }

/* ---------------- 响应式 ---------------- */

@media (max-width: 1024px) {
  .flow p { font-size: 13.2px; }
}

@media (max-width: 720px) {
  .links { display: none; }
  .navcta { margin-left: auto; }
  .brand em { display: none; }
  .hero { padding-top: 96px; padding-bottom: 44px; }
  .hero h1 { font-size: clamp(34px, 9.4vw, 46px); }
  .lede { font-size: 15px; }
  .head p { font-size: 14.6px; }
  .stats { gap: 18px 12px; justify-content: space-between; }
  .stats > div { flex: 1 1 0; min-width: 0; }
  .stats dd { font-size: 24px; }
  .phones { grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 14px; }
  /* 移动端仍是两行三列，只收紧图标与字号 */
  .flow { gap: 22px 10px; }
  .flow .dot { width: 42px; height: 42px; border-radius: 13px; }
  .flow .dot svg { width: 19px; height: 19px; }
  .flow h3 { margin: 10px 0 4px; font-size: 13.8px; }
  .flow p { max-width: none; font-size: 11.6px; line-height: 1.5; }
  .phone { max-width: none; padding: 7px; border-radius: 20px; }
  .phone img { border-radius: 14px; }
  .phone b { margin: 9px 2px 2px; font-size: 11.5px; line-height: 1.4; }
  .foot .wrap { flex-direction: column; align-items: flex-start; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .reveal { opacity: 1; transform: none; transition: none; }
  .btn:hover, .flow li:hover .dot { transform: none; }
}