/* 爬山虎学园 · 对外网站样式（纯静态，零依赖） */
:root {
  --primary: #FF6B6B;
  --primary-dark: #e85555;
  --primary-soft: #fff1ec;
  --ink: #22272e;
  --muted: #6a737d;
  --bg: #f6f7f9;
  --card: #ffffff;
  --line: #e6e8eb;
  --radius: 16px;
  --maxw: 1080px;
}
* { box-sizing: border-box; margin: 0; padding: 0; }
body {
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", sans-serif;
  background: var(--bg);
  color: var(--ink);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}
a { color: var(--primary); text-decoration: none; }
img { max-width: 100%; display: block; }

/* 顶部导航 */
.nav {
  position: sticky; top: 0; z-index: 10;
  display: flex; align-items: center; justify-content: space-between;
  padding: 14px 22px; background: rgba(255,255,255,.9);
  backdrop-filter: saturate(180%) blur(10px);
  border-bottom: 1px solid var(--line);
}
.nav .brand { font-weight: 800; font-size: 18px; color: var(--ink); }
.nav .brand span { color: var(--primary); }
.nav .links { display: flex; gap: 18px; font-size: 14px; }
.nav .links a { color: var(--muted); }
.nav .links a:hover { color: var(--primary); }

/* 容器 */
.wrap { max-width: var(--maxw); margin: 0 auto; padding: 0 22px; }
section { padding: 56px 0; }
.section-title { text-align: center; font-size: 26px; font-weight: 800; margin-bottom: 8px; }
.section-sub { text-align: center; color: var(--muted); margin-bottom: 36px; }

/* Hero */
.hero {
  background: linear-gradient(135deg, var(--primary), #ff9a8b);
  color: #fff; text-align: center; padding: 84px 22px 72px;
}
.hero .logo {
  width: 84px; height: 84px; border-radius: 22px; background: #fff;
  display: flex; align-items: center; justify-content: center;
  margin: 0 auto 22px; box-shadow: 0 12px 30px rgba(0,0,0,.18);
  font-size: 44px;
}
.hero h1 { font-size: 40px; font-weight: 900; letter-spacing: 1px; }
.hero .tagline { font-size: 18px; margin: 14px 0 28px; opacity: .95; }
.hero-cta { display: flex; gap: 14px; justify-content: center; flex-wrap: wrap; }
.btn-primary {
  background: #fff; color: var(--primary); font-weight: 700;
  padding: 13px 28px; border-radius: 999px; font-size: 15px;
  transition: transform .15s ease, box-shadow .15s ease;
  box-shadow: 0 8px 20px rgba(0,0,0,.15);
}
.btn-primary:hover { transform: translateY(-2px); }
.btn-ghost {
  border: 2px solid rgba(255,255,255,.8); color: #fff;
  padding: 12px 26px; border-radius: 999px; font-size: 15px; font-weight: 600;
}
.btn-ghost:hover { background: rgba(255,255,255,.15); }

/* 功能卡片 */
.grid {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 18px;
}
.card {
  background: var(--card); border: 1px solid var(--line);
  border-radius: var(--radius); padding: 26px 22px;
}
.card .ico {
  width: 46px; height: 46px; border-radius: 12px;
  background: var(--primary-soft); color: var(--primary);
  display: flex; align-items: center; justify-content: center;
  font-size: 24px; margin-bottom: 14px;
}
.card h3 { font-size: 17px; margin-bottom: 8px; }
.card p { color: var(--muted); font-size: 14px; }

/* 截图 */
.shot-grid {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 18px;
}
.shot-grid figure {
  background: var(--card); border: 1px solid var(--line);
  border-radius: var(--radius); overflow: hidden;
}
.shot-grid img { width: 100%; }
.shot-grid figcaption {
  padding: 10px 14px; font-size: 13px; color: var(--muted); text-align: center;
}

/* 下载 */
.download { text-align: center; background: var(--card); border-top: 1px solid var(--line); }
.download .qr {
  width: 200px; height: 200px; margin: 18px auto;
  border: 1px solid var(--line); border-radius: 12px; padding: 8px;
}
.download .hint { color: var(--muted); font-size: 14px; }

/* 页脚 */
footer {
  background: #1f242a; color: #c9d1d9; text-align: center;
  padding: 34px 22px; font-size: 14px;
}
footer .flinks { display: flex; gap: 16px; justify-content: center; margin-bottom: 12px; flex-wrap: wrap; }
footer .flinks a { color: #9fb3c8; }
footer .flinks a:hover { color: #fff; }
footer p { color: #8b949e; }

/* 文档页（隐私政策 / 用户协议） */
.doc { max-width: 820px; margin: 0 auto; padding: 40px 22px 70px; }
.doc h1 { font-size: 28px; margin-bottom: 6px; }
.doc .updated { color: var(--muted); font-size: 13px; margin-bottom: 28px; }
.doc h2 {
  font-size: 19px; margin: 30px 0 10px; padding-left: 12px;
  border-left: 4px solid var(--primary);
}
.doc p, .doc li { color: #3a4149; font-size: 15px; margin-bottom: 10px; }
.doc ul { padding-left: 22px; margin-bottom: 10px; }
.doc .placeholder {
  background: var(--primary-soft); color: var(--primary-dark);
  border-radius: 8px; padding: 2px 8px; font-weight: 600;
}
.doc .back { display: inline-block; margin-top: 30px; font-weight: 600; }

@media (max-width: 600px) {
  .hero h1 { font-size: 30px; }
  .nav .links { display: none; }
  section { padding: 40px 0; }
}