:root {
  --primary: #18c7c6;
  --primary-deep: #08aeb4;
  --primary-soft: #ddf8f7;
  --accent: #ff6433;
  --text: #1d1d1f;
  --text-2: #6e6e73;
  --text-3: #9aa4aa;
  --surface: #f5f5f7;
  --card: #ffffff;
  --border: rgba(0, 0, 0, 0.08);
  --radius: 22px;
  --shadow: 0 12px 40px rgba(0, 0, 0, 0.08);
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro SC", "PingFang SC", "Helvetica Neue", "Microsoft YaHei", sans-serif;
  color: var(--text);
  background: #fff;
  line-height: 1.65;
  letter-spacing: 0.01em;
  -webkit-font-smoothing: antialiased;
}

img { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }

.container { width: min(1080px, 90%); margin: 0 auto; }

/* ===== 导航：毛玻璃细条 ===== */
.nav {
  position: sticky; top: 0; z-index: 100;
  background: rgba(255, 255, 255, 0.72);
  backdrop-filter: saturate(180%) blur(20px);
  -webkit-backdrop-filter: saturate(180%) blur(20px);
  border-bottom: 1px solid var(--border);
}
.nav-inner {
  display: flex; align-items: center; justify-content: space-between;
  height: 56px;
}
.nav-right { display: flex; align-items: center; gap: 14px; }
.nav-logo { display: flex; align-items: center; gap: 9px; font-size: 20px; font-weight: 700; letter-spacing: -0.01em; }
.nav-logo img { height: 34px; width: 34px; border-radius: 8px; }
.nav-logo .dot { color: var(--primary); }
.nav-burger {
  display: none; flex-direction: column; justify-content: center; gap: 6px;
  width: 40px; height: 40px; padding: 0 9px;
  background: transparent; border: none; cursor: pointer;
}
.nav-burger span { display: block; height: 1.5px; width: 100%; background: var(--text); border-radius: 2px; transition: transform 0.25s ease; }
.nav-burger.open span:first-child { transform: translateY(3.75px) rotate(45deg); }
.nav-burger.open span:last-child { transform: translateY(-3.75px) rotate(-45deg); }
.nav-links { display: flex; gap: 36px; list-style: none; }
.nav-links a { color: var(--text-2); font-size: 14px; transition: color 0.2s; }
.nav-links a:hover { color: var(--text); }
.nav-cta {
  background: var(--text); color: #fff;
  padding: 7px 18px; border-radius: 980px; font-size: 13px; font-weight: 500;
  transition: opacity 0.2s;
}
.nav-cta:hover { opacity: 0.8; }

/* ===== 首屏：居中大标题 ===== */
.hero {
  padding: 120px 0 80px;
  text-align: center;
  background:
    radial-gradient(900px 420px at 50% -8%, rgba(24, 199, 198, 0.10), transparent 65%);
}
.hero-badge {
  display: inline-block; color: var(--accent); background: transparent;
  font-size: 15px; font-weight: 600; letter-spacing: 0.12em;
  margin-bottom: 18px;
}
.hero h1 {
  font-size: clamp(44px, 7vw, 80px);
  line-height: 1.1; font-weight: 700; letter-spacing: -0.02em;
  background: linear-gradient(120deg, #1d1d1f 30%, var(--primary-deep));
  -webkit-background-clip: text; background-clip: text; -webkit-text-fill-color: transparent;
}
.hero p.sub {
  color: var(--text-2); font-size: clamp(17px, 2vw, 21px);
  margin: 26px auto 40px; max-width: 640px; line-height: 1.55;
}
.hero-actions { display: flex; gap: 18px; justify-content: center; flex-wrap: wrap; }
.btn {
  display: inline-block; padding: 15px 34px; border-radius: 980px;
  font-size: 17px; font-weight: 500; transition: transform 0.2s, opacity 0.2s;
}
.btn:hover { transform: scale(1.03); }
.btn-primary { background: var(--primary); color: #fff; }
.btn-primary:hover { background: var(--primary-deep); }
.btn-ghost { background: transparent; border: 1px solid var(--border); color: var(--text); }
.btn-ghost:hover { background: var(--surface); }
.hero-figure { margin-top: 64px; }
.hero-figure img {
  border-radius: 28px; box-shadow: var(--shadow);
  aspect-ratio: 16 / 9; object-fit: cover; background: var(--surface);
  margin: 0 auto; max-height: 520px;
}

/* ===== 通用板块：通栏交替 ===== */
.section { padding: 110px 0; }
.section.alt { background: var(--surface); }
.section.dark { background: #000; color: #f5f5f7; }
.section-head { text-align: center; max-width: 720px; margin: 0 auto 64px; }
.section-head h2 {
  font-size: clamp(32px, 4.5vw, 52px); font-weight: 700;
  letter-spacing: -0.02em; line-height: 1.15; margin-bottom: 18px;
}
.section-head p { color: var(--text-2); font-size: 18px; }
.section.dark .section-head p { color: #a1a1a6; }
.section-head .kicker {
  display: block; color: var(--primary-deep); font-size: 14px; font-weight: 600;
  letter-spacing: 0.18em; margin-bottom: 14px;
}
.section.dark .section-head .kicker { color: var(--primary); }

/* 卡片：无描边浅灰圆角 */
.grid-4 { display: grid; grid-template-columns: repeat(4, 1fr); gap: 18px; }
.card {
  background: var(--card); border-radius: var(--radius);
  padding: 36px 28px; transition: transform 0.25s ease;
}
.section:not(.alt) .card { background: var(--surface); }
.card:hover { transform: translateY(-6px); }
.card .icon { font-size: 36px; margin-bottom: 18px; }
.card h3 { font-size: 19px; font-weight: 600; margin-bottom: 8px; letter-spacing: -0.01em; }
.card p { color: var(--text-2); font-size: 14.5px; }

/* 分类 */
.cats { display: grid; grid-template-columns: repeat(8, 1fr); gap: 14px; }
.cat {
  background: #fff; border-radius: 18px; padding: 26px 8px; text-align: center;
  transition: transform 0.2s ease, box-shadow 0.2s ease; cursor: default;
}
.cat:hover { transform: translateY(-4px); box-shadow: var(--shadow); }
.cat .icon { font-size: 32px; }
.cat .name { font-size: 14px; margin-top: 10px; color: var(--text); font-weight: 500; }

/* 安全：深色通栏 */
.section.dark .card { background: #1c1c1e; }
.section.dark .card h3 { color: #f5f5f7; }
.section.dark .card p { color: #a1a1a6; }

/* 关于 */
.about-grid { display: grid; grid-template-columns: 1.25fr 1fr; gap: 64px; align-items: center; }
.about-copy p { color: var(--text-2); margin-bottom: 16px; font-size: 17px; }
.stats { display: grid; grid-template-columns: repeat(3, 1fr); gap: 14px; margin-top: 40px; }
.stat { background: var(--surface); border-radius: 18px; text-align: center; padding: 28px 8px; }
.stat .value { font-size: 34px; font-weight: 700; color: var(--primary-deep); letter-spacing: -0.02em; }
.stat .label { color: var(--text-3); font-size: 13px; }

/* ===== 下载：深色 ===== */
.download {
  background:
    radial-gradient(720px 380px at 50% 118%, rgba(24, 199, 198, 0.22), transparent 72%),
    #000;
  color: #f5f5f7; text-align: center; padding: 120px 0;
}
.download .section-head { margin-bottom: 56px; }
.download .kicker { color: var(--primary); }
.download h2 {
  font-size: clamp(34px, 5vw, 56px); font-weight: 700;
  letter-spacing: -0.02em; color: #fff;
  -webkit-text-fill-color: #fff;
  background: none;
}
.download .section-head p { color: #a1a1a6; font-size: 19px; }
.qr-row { display: flex; gap: 24px; justify-content: center; flex-wrap: wrap; }
.qr-item {
  background: #fff; border-radius: 24px; padding: 28px 26px 24px;
  width: 216px; color: var(--text);
}
.qr-item img, .qr-placeholder {
  width: 148px; height: 148px; margin: 0 auto 16px; object-fit: contain;
  background: var(--surface); border-radius: 14px;
}
.qr-placeholder {
  display: flex; align-items: center; justify-content: center;
  color: var(--text-3); font-size: 12px; border: 1px dashed #d2d7dc;
}
.qr-item .qr-title { font-weight: 600; font-size: 16px; letter-spacing: -0.01em; }
.qr-item .qr-desc { color: var(--text-3); font-size: 12.5px; margin-top: 4px; }
.dl-mobile-hint { margin-top: 44px; }
.dl-mobile-btn {
  display: inline-block; padding: 13px 30px; border-radius: 980px;
  background: var(--primary); color: #fff; font-size: 15px; font-weight: 500;
  transition: transform 0.2s, background 0.2s;
}
.dl-mobile-btn:hover { background: var(--primary-deep); transform: scale(1.03); }

/* ===== 页脚 ===== */
.footer { background: var(--surface); color: var(--text-2); padding: 64px 0 32px; font-size: 14px; }
.footer-grid { display: grid; grid-template-columns: 2fr 1fr 1fr; gap: 40px; margin-bottom: 48px; }
.footer h4 { color: var(--text); margin-bottom: 16px; font-size: 14px; font-weight: 600; }
.footer ul { list-style: none; }
.footer li { margin-bottom: 10px; }
.footer a:hover { color: var(--primary-deep); }
.footer .brand-line { font-size: 22px; color: var(--text); font-weight: 700; margin-bottom: 12px; letter-spacing: -0.01em; }
.footer-logo { height: 72px; width: auto; margin-bottom: 16px; border-radius: 12px; }
.footer .icp {
  border-top: 1px solid var(--border); padding-top: 24px;
  text-align: center; color: var(--text-3); font-size: 13px;
}

/* ===== 滚动渐入 ===== */
.reveal { opacity: 0; transform: translateY(28px); transition: opacity 0.7s ease, transform 0.7s ease; }
.reveal.in { opacity: 1; transform: none; }

/* ===== 响应式 ===== */
@media (max-width: 900px) {
  .nav-burger { display: flex; }
  .nav-cta { display: none; }
  .nav-links {
    display: flex; flex-direction: column; gap: 0;
    position: absolute; top: 56px; left: 0; right: 0;
    background: rgba(255, 255, 255, 0.96);
    backdrop-filter: saturate(180%) blur(20px);
    -webkit-backdrop-filter: saturate(180%) blur(20px);
    border-bottom: 1px solid var(--border);
    max-height: 0; overflow: hidden;
    transition: max-height 0.3s ease;
  }
  .nav-links.open { max-height: 320px; }
  .nav-links li { border-top: 1px solid var(--border); }
  .nav-links li:first-child { border-top: none; }
  .nav-links a { display: block; padding: 14px 5%; font-size: 15px; color: var(--text); }
  .grid-4 { grid-template-columns: repeat(2, 1fr); }
  .cats { grid-template-columns: repeat(4, 1fr); }
  .about-grid { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr; gap: 28px; }
  .section { padding: 72px 0; }
  .hero { padding: 80px 0 56px; }
  .qr-row { gap: 16px; }
  .qr-item { width: 164px; padding: 20px 16px 18px; }
  .qr-item img, .qr-placeholder { width: 120px; height: 120px; }
  .dl-mobile-btn { font-size: 14px; padding: 12px 24px; }
}