:root {
  --bg: #FFFCF5;
  --bg-soft: #F8F0E1;
  --card: #FFFFFF;
  --fg: #3B2A20;
  --fg-2: #8C6A55;
  --accent: #E9A866;
  --accent-text: #A8642A;
  --on-accent: #3B2A20;
  --line: rgba(59, 42, 32, .12);
  --shadow: 0 18px 50px rgba(59, 42, 32, .14);
  --radius: 22px;
  color-scheme: light dark;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #1A1512;
    --bg-soft: #231C17;
    --card: #2A221C;
    --fg: #F3EADB;
    --fg-2: #B9A592;
    --accent: #E9A866;
    --accent-text: #E9A866;
    --on-accent: #1A1512;
    --line: rgba(243, 234, 219, .12);
    --shadow: 0 18px 50px rgba(0, 0, 0, .45);
  }
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font: 17px/1.7 -apple-system, BlinkMacSystemFont, "SF Pro Text", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Segoe UI", sans-serif;
  -webkit-font-smoothing: antialiased;
}

a { color: inherit; }

img { display: block; max-width: 100%; height: auto; }

.wrap { width: min(1120px, 100% - 40px); margin: 0 auto; }

/* 导航 */
.nav {
  position: sticky; top: 0; z-index: 10;
  background: color-mix(in srgb, var(--bg) 85%, transparent);
  backdrop-filter: saturate(1.4) blur(14px);
  -webkit-backdrop-filter: saturate(1.4) blur(14px);
  border-bottom: 1px solid var(--line);
}
.nav .wrap { display: flex; align-items: center; gap: 28px; height: 64px; }
.brand { display: flex; align-items: center; gap: 10px; font-weight: 700; font-size: 18px; text-decoration: none; }
.brand img { width: 34px; height: 34px; border-radius: 9px; }
.nav-links { display: flex; gap: 22px; margin-left: auto; font-size: 15px; }
.nav-links a { text-decoration: none; color: var(--fg-2); }
.nav-links a:hover { color: var(--fg); }
.lang { border: 1px solid var(--line); border-radius: 999px; padding: 2px 12px; }

/* 按钮 */
.btn {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 13px 24px; border-radius: 999px;
  font-weight: 600; font-size: 16px; text-decoration: none;
  border: 1.5px solid var(--fg);
}
.btn-primary { background: var(--accent); border-color: var(--accent); color: var(--on-accent); }
.btn-primary:hover { filter: brightness(1.04); }
.btn-ghost:hover { background: var(--bg-soft); }

/* 首屏 */
.hero { padding: 72px 0 40px; overflow: hidden; }
.hero .wrap { display: grid; grid-template-columns: 1.1fr .9fr; gap: 48px; align-items: center; }
.eyebrow {
  display: inline-block; margin-bottom: 18px;
  padding: 4px 14px; border-radius: 999px;
  background: var(--bg-soft); color: var(--accent-text);
  font-size: 14px; font-weight: 600;
}
h1 { font-size: clamp(38px, 5.4vw, 62px); line-height: 1.18; margin: 0 0 22px; letter-spacing: -.01em; }
h1 em { font-style: normal; background: linear-gradient(transparent 62%, color-mix(in srgb, var(--accent) 55%, transparent) 62%); }
.lead { font-size: 19px; color: var(--fg-2); margin: 0 0 32px; max-width: 34em; }
.cta { display: flex; flex-wrap: wrap; gap: 14px; align-items: center; }
.note { font-size: 14px; color: var(--fg-2); margin-top: 16px; }

.hero-visual { position: relative; display: flex; justify-content: center; }
.hero-visual .mascot {
  position: absolute; left: -10px; bottom: 30px; width: 150px;
  border-radius: 34px; box-shadow: var(--shadow);
  transform: rotate(-8deg);
}

/* 手机外框 */
.phone {
  width: 280px; aspect-ratio: 920 / 2000;
  border-radius: 44px; padding: 10px;
  background: #241A14;
  box-shadow: var(--shadow), inset 0 0 0 2px #4a3a2f;
}
.phone img { width: 100%; height: 100%; object-fit: cover; border-radius: 35px; }
.phone.sm { width: 250px; }

/* 区块 */
section { padding: 84px 0; }
.soft { background: var(--bg-soft); }
h2 { font-size: clamp(28px, 3.6vw, 40px); line-height: 1.3; margin: 0 0 14px; }
.section-head { text-align: center; max-width: 680px; margin: 0 auto 52px; }
.section-head p { color: var(--fg-2); margin: 0; font-size: 18px; }

/* 三步 */
.steps { display: grid; grid-template-columns: repeat(3, 1fr); gap: 22px; counter-reset: step; }
.step {
  background: var(--card); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 28px 26px;
}
.step::before {
  counter-increment: step; content: counter(step);
  display: grid; place-items: center; width: 40px; height: 40px; margin-bottom: 16px;
  border-radius: 50%; background: var(--accent); color: var(--on-accent); font-weight: 700;
}
.step h3 { margin: 0 0 8px; font-size: 20px; }
.step p { margin: 0; color: var(--fg-2); font-size: 16px; }

/* 功能 */
.feature { display: grid; grid-template-columns: 1fr 1fr; gap: 64px; align-items: center; }
.feature + .feature { margin-top: 96px; }
.feature.flip .feature-media { order: 2; }
.feature-media { display: flex; justify-content: center; }
.feature h2 { margin-bottom: 18px; }
.feature p.lead { margin-bottom: 20px; }
.ticks { list-style: none; padding: 0; margin: 0; }
.ticks li { position: relative; padding-left: 30px; margin: 10px 0; }
.ticks li::before {
  content: ""; position: absolute; left: 0; top: .42em;
  width: 18px; height: 18px; border-radius: 50%; background: var(--accent);
}
.ticks li::after {
  content: ""; position: absolute; left: 6px; top: calc(.42em + 4px);
  width: 5px; height: 9px; border: solid var(--on-accent); border-width: 0 2px 2px 0; transform: rotate(45deg);
}

/* 承诺卡片 */
.cards { display: grid; grid-template-columns: repeat(3, 1fr); gap: 22px; }
.card {
  background: var(--card); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 30px 28px;
}
.card .ico { font-size: 30px; line-height: 1; margin-bottom: 14px; }
.card h3 { margin: 0 0 8px; font-size: 20px; }
.card p { margin: 0; color: var(--fg-2); font-size: 16px; }

/* 下载 */
.platforms { display: grid; grid-template-columns: repeat(2, 1fr); gap: 22px; max-width: 860px; margin: 0 auto; }
.platform {
  display: flex; gap: 20px; align-items: center;
  background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); padding: 26px;
}
.platform img { width: 76px; height: 76px; border-radius: 18px; flex: none; }
.platform h3 { margin: 0 0 4px; font-size: 20px; }
.platform p { margin: 0; color: var(--fg-2); font-size: 15px; }
.badge {
  display: inline-block; margin-top: 10px; padding: 3px 12px; border-radius: 999px;
  background: var(--accent); color: var(--on-accent); font-size: 13px; font-weight: 600;
}

/* 常见问题 */
.faq { max-width: 820px; margin: 0 auto; }
.faq details {
  background: var(--card); border: 1px solid var(--line); border-radius: 16px;
  padding: 18px 22px; margin-bottom: 12px;
}
.faq summary { cursor: pointer; font-weight: 600; list-style: none; display: flex; justify-content: space-between; gap: 16px; }
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after { content: "+"; color: var(--accent-text); font-size: 22px; line-height: 1.2; }
.faq details[open] summary::after { content: "−"; }
.faq details p { margin: 12px 0 2px; color: var(--fg-2); }

/* 页脚 */
footer { padding: 40px 0 56px; border-top: 1px solid var(--line); color: var(--fg-2); font-size: 14px; }
footer .wrap { display: flex; flex-wrap: wrap; gap: 14px 28px; align-items: center; }
footer nav { display: flex; flex-wrap: wrap; gap: 18px; margin-left: auto; }
footer a { text-decoration: none; }
footer a:hover { color: var(--fg); }

@media (max-width: 860px) {
  .nav-links a:not(.lang) { display: none; }
  .hero { padding-top: 44px; }
  .hero .wrap, .feature { grid-template-columns: 1fr; gap: 40px; }
  .hero-visual .mascot { width: 110px; left: 4%; }
  .feature.flip .feature-media { order: 0; }
  .steps, .cards, .platforms { grid-template-columns: 1fr; }
  section { padding: 64px 0; }
  .feature + .feature { margin-top: 72px; }
  footer nav { margin-left: 0; }
}

/* 说明与协议页 */
.doc { padding: 56px 0 88px; }
.prose { max-width: 780px; }
.prose h1 { font-size: clamp(30px, 4vw, 42px); margin-bottom: 28px; }
.prose h2 { font-size: 24px; margin: 44px 0 12px; }
.prose h3 { font-size: 20px; margin: 32px 0 10px; }
.prose p, .prose li { margin: 0 0 14px; }
.prose ul, .prose ol { padding-left: 1.4em; margin: 0 0 14px; }
.prose li { margin-bottom: 8px; }
.prose a { color: var(--accent-text); text-underline-offset: 3px; }
.prose code { font: 15px ui-monospace, SFMono-Regular, Menlo, monospace; background: var(--bg-soft); padding: 1px 6px; border-radius: 6px; }
.prose figure { margin: 18px 0 26px; }
.prose figure img { border-radius: 14px; border: 1px solid var(--line); box-shadow: var(--shadow); }
.callout { background: var(--bg-soft); border-left: 4px solid var(--accent); border-radius: 12px; padding: 18px 22px 6px; margin: 0 0 24px; }
.table { overflow-x: auto; margin: 0 0 22px; }
.prose table { border-collapse: collapse; width: 100%; font-size: 15px; line-height: 1.6; }
.prose th, .prose td { border: 1px solid var(--line); padding: 10px 12px; text-align: left; vertical-align: top; }
.prose th { background: var(--bg-soft); }

/* 下载：手机端、电脑端各两项 */
.platform-group { max-width: 860px; margin: 36px auto 14px; font-size: 15px; color: var(--fg-2); font-weight: 600; letter-spacing: .04em; }
.platform-group:first-of-type { margin-top: 0; }
a.platform { color: inherit; text-decoration: none; }
a.platform:not(.pending):hover { border-color: var(--accent); }
.platform.pending { cursor: default; }
.platform.pending .badge { background: var(--bg-soft); color: var(--accent-text); }