/* 飞书式界面：白底、灰底分区、品牌蓝、轻阴影与圆角 */

:root {
  color-scheme: light;
  --bg: #f5f6f7;
  --bg-elevated: #ffffff;
  --fg: #1f2329;
  --fg-secondary: #646a73;
  --fg-tertiary: #8f959e;
  --line: #dee0e3;
  --line-soft: #e8e9eb;
  --accent: #3370ff;
  --accent-hover: #245bdb;
  --accent-soft: rgba(51, 112, 255, 0.08);
  --accent-soft-strong: rgba(51, 112, 255, 0.12);
  --shadow-sm: 0 1px 2px rgba(31, 35, 41, 0.06);
  --shadow-md: 0 4px 16px rgba(31, 35, 41, 0.08);
  --radius: 12px;
  --radius-lg: 16px;
  --header-h: 56px;
  --wide: 1080px;
  --max: 720px;
  --font: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei",
    -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: var(--font);
  background: var(--bg);
  color: var(--fg);
  line-height: 1.6;
  font-size: 14px;
  -webkit-font-smoothing: antialiased;
}

a {
  color: var(--accent);
  text-decoration: none;
}

a:hover {
  color: var(--accent-hover);
}

.wrap {
  width: min(100% - 40px, var(--wide));
  margin-inline: auto;
}

/* —— 顶栏 —— */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  height: var(--header-h);
  background: rgba(255, 255, 255, 0.92);
  border-bottom: 1px solid var(--line-soft);
  backdrop-filter: saturate(180%) blur(12px);
}

.site-header .inner {
  height: var(--header-h);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: var(--fg);
  font-weight: 600;
  font-size: 16px;
  text-decoration: none;
}

.brand:hover {
  color: var(--fg);
}

.brand-icon {
  width: 28px;
  height: 28px;
  border-radius: 7px;
  display: block;
  box-shadow: var(--shadow-sm);
}

.nav {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 4px 4px;
}

.nav a {
  color: var(--fg-secondary);
  font-size: 14px;
  padding: 6px 12px;
  border-radius: 6px;
  text-decoration: none;
}

.nav a:hover {
  color: var(--fg);
  background: var(--bg);
}

.nav a[aria-current="page"] {
  color: var(--accent);
  background: var(--accent-soft);
  font-weight: 500;
}

/* —— 首页 Hero —— */
.hero {
  padding: 56px 0 40px;
  background:
    radial-gradient(ellipse 80% 60% at 80% 0%, rgba(51, 112, 255, 0.08), transparent 55%),
    var(--bg);
}

.hero-grid {
  display: grid;
  gap: 40px;
  align-items: center;
}

@media (min-width: 880px) {
  .hero-grid {
    grid-template-columns: 1.15fr 0.85fr;
    gap: 48px;
  }
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 13px;
  font-weight: 500;
  color: var(--accent);
  background: var(--accent-soft);
  padding: 4px 10px;
  border-radius: 4px;
  margin-bottom: 16px;
}

h1 {
  margin: 0 0 12px;
  font-size: clamp(28px, 4vw, 40px);
  line-height: 1.25;
  font-weight: 600;
  letter-spacing: -0.02em;
  color: var(--fg);
}

.lead {
  margin: 0 0 28px;
  font-size: 16px;
  line-height: 1.7;
  color: var(--fg-secondary);
  max-width: 34em;
}

.actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 40px;
  padding: 0 18px;
  border-radius: 6px;
  font-weight: 500;
  font-size: 14px;
  border: 1px solid transparent;
  cursor: pointer;
  transition: background 0.15s ease, border-color 0.15s ease, color 0.15s ease;
  text-decoration: none;
}

.btn:hover {
  text-decoration: none;
}

.btn-primary {
  background: var(--accent);
  color: #fff;
}

.btn-primary:hover {
  background: var(--accent-hover);
  color: #fff;
}

.btn-secondary {
  background: var(--bg-elevated);
  color: var(--fg);
  border-color: var(--line);
  box-shadow: var(--shadow-sm);
}

.btn-secondary:hover {
  border-color: var(--accent);
  color: var(--accent);
}

.hero-visual {
  display: flex;
  justify-content: center;
}

.hero-card {
  width: min(100%, 360px);
  background: var(--bg-elevated);
  border: 1px solid var(--line-soft);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
  padding: 28px 24px 24px;
  text-align: center;
}

.hero-card .app-icon {
  width: 96px;
  height: 96px;
  border-radius: 22px;
  margin: 0 auto 16px;
  display: block;
  box-shadow: 0 8px 24px rgba(51, 112, 255, 0.18);
}

.hero-card h2 {
  margin: 0 0 8px;
  font-size: 18px;
  font-weight: 600;
}

.hero-card .sub {
  margin: 0 0 18px;
  color: var(--fg-secondary);
  font-size: 13px;
}

.hero-card ul {
  margin: 0;
  padding: 0;
  list-style: none;
  text-align: left;
}

.hero-card li {
  display: flex;
  gap: 10px;
  align-items: flex-start;
  padding: 10px 12px;
  border-radius: 8px;
  font-size: 13px;
  color: var(--fg-secondary);
}

.hero-card li + li {
  margin-top: 4px;
}

.hero-card li:nth-child(odd) {
  background: var(--bg);
}

.hero-card li::before {
  content: "";
  width: 6px;
  height: 6px;
  margin-top: 7px;
  border-radius: 50%;
  background: var(--accent);
  flex-shrink: 0;
}

/* —— 分区 —— */
.section {
  padding: 8px 0 48px;
}

.section-head {
  margin-bottom: 20px;
}

.section-head h2 {
  margin: 0 0 6px;
  font-size: 22px;
  font-weight: 600;
}

.section-head p {
  margin: 0;
  color: var(--fg-secondary);
  font-size: 14px;
}

.feature-grid {
  display: grid;
  gap: 12px;
}

@media (min-width: 720px) {
  .feature-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

.feature {
  background: var(--bg-elevated);
  border: 1px solid var(--line-soft);
  border-radius: var(--radius);
  padding: 18px 16px;
  box-shadow: var(--shadow-sm);
  transition: border-color 0.15s ease, box-shadow 0.15s ease;
}

.feature:hover {
  border-color: #c9d4f0;
  box-shadow: var(--shadow-md);
}

.feature-icon {
  width: 36px;
  height: 36px;
  border-radius: 8px;
  background: var(--accent-soft);
  color: var(--accent);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 16px;
  font-weight: 600;
  margin-bottom: 12px;
}

.feature h3 {
  margin: 0 0 6px;
  font-size: 15px;
  font-weight: 600;
}

.feature h3 a {
  color: inherit;
}

.feature h3 a:hover {
  color: var(--accent);
}

.feature p {
  margin: 0;
  color: var(--fg-secondary);
  font-size: 13px;
  line-height: 1.65;
}

/* —— 页脚 —— */
.site-footer {
  border-top: 1px solid var(--line-soft);
  background: var(--bg-elevated);
  padding: 20px 0 28px;
  color: var(--fg-tertiary);
  font-size: 13px;
}

.site-footer .inner {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 20px;
  justify-content: space-between;
  align-items: center;
}

.site-footer a {
  color: var(--fg-secondary);
}

.site-footer a:hover {
  color: var(--accent);
}

/* —— 协议页 —— */
.legal-page {
  width: min(100% - 40px, var(--max));
  margin: 24px auto 48px;
  background: var(--bg-elevated);
  border: 1px solid var(--line-soft);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
  padding: 28px 28px 36px;
}

.legal-page h1 {
  font-size: 24px;
  margin-bottom: 8px;
}

.legal-page h2 {
  font-size: 16px;
  font-weight: 600;
  margin: 28px 0 10px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--line-soft);
}

.legal-page p,
.legal-page li {
  font-size: 14px;
  color: var(--fg);
  line-height: 1.7;
}

.legal-page p {
  color: var(--fg-secondary);
}

.legal-page ul {
  padding-left: 1.2rem;
  color: var(--fg-secondary);
}

.legal-page table {
  border-collapse: collapse;
  width: 100%;
  font-size: 13px;
  margin: 12px 0;
}

.legal-page th,
.legal-page td {
  border: 1px solid var(--line);
  padding: 8px 10px;
  text-align: left;
  vertical-align: top;
}

.legal-page th {
  background: var(--bg);
  font-weight: 500;
}

.lang-switch {
  font-size: 13px;
  margin-bottom: 16px;
}

.lang-switch a {
  display: inline-flex;
  padding: 4px 10px;
  border-radius: 4px;
  background: var(--accent-soft);
  color: var(--accent);
  font-weight: 500;
}

.lang-switch a:hover {
  background: var(--accent-soft-strong);
}

@media (max-width: 560px) {
  .legal-page {
    padding: 20px 16px 28px;
  }

  .nav a {
    padding: 6px 8px;
  }
}