:root {
  --bg: #0a1020;
  --bg2: #0f1830;
  --panel: #121d38;
  --panel2: #16223f;
  --line: #243456;
  --text: #e6edf7;
  --muted: #93a4c4;
  --cyan: #36d6e7;
  --blue: #4d8dff;
  --accent: #ffb547;
  --ok: #45d483;
  --err: #ff6b6b;
  --radius: 14px;
  --maxw: 1080px;
}

* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  background: radial-gradient(1200px 600px at 70% -10%, #14264e 0%, var(--bg) 55%) fixed;
  color: var(--text);
  line-height: 1.6;
  min-height: 100vh;
}
a { color: var(--cyan); text-decoration: none; }
a:hover { text-decoration: underline; }

/* 导航 */
.nav {
  display: flex; align-items: center; gap: 18px;
  max-width: var(--maxw); margin: 0 auto; padding: 16px 20px;
  position: sticky; top: 0; z-index: 20;
  background: rgba(10, 16, 32, 0.82); backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--line);
}
.brand { font-weight: 800; font-size: 20px; letter-spacing: 0.5px; color: var(--text); }
.brand .ai { color: var(--cyan); }
.nav .links { margin-left: auto; display: flex; gap: 18px; flex-wrap: wrap; }
.nav .links a { color: var(--muted); font-weight: 600; }
.nav .links a:hover, .nav .links a.active { color: var(--cyan); text-decoration: none; }

/* 布局 */
.wrap { max-width: var(--maxw); margin: 0 auto; padding: 28px 20px 60px; }
.grid { display: grid; gap: 18px; }
.grid.cols-2 { grid-template-columns: repeat(2, 1fr); }
.grid.cols-3 { grid-template-columns: repeat(3, 1fr); }
@media (max-width: 820px) { .grid.cols-2, .grid.cols-3 { grid-template-columns: 1fr; } }

/* 卡片 */
.card {
  background: linear-gradient(180deg, var(--panel) 0%, var(--panel2) 100%);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 22px;
}
.card h3 { margin: 0 0 10px; color: var(--cyan); }
.card p { color: var(--muted); margin: 0; }

/* Hero */
.hero { text-align: center; padding: 56px 20px 40px; }
.hero .badge {
  display: inline-block; padding: 6px 14px; border: 1px solid var(--line);
  border-radius: 999px; color: var(--muted); font-size: 13px; margin-bottom: 18px;
}
.hero h1 { font-size: 44px; margin: 0 0 14px; line-height: 1.15; }
.hero h1 .ai { color: var(--cyan); }
.hero .sub { color: var(--muted); font-size: 18px; max-width: 720px; margin: 0 auto 26px; }
.hero .actions { display: flex; gap: 14px; justify-content: center; flex-wrap: wrap; }

/* 按钮 */
.btn {
  display: inline-block; padding: 12px 22px; border-radius: 10px; font-weight: 700;
  border: 1px solid var(--line); background: var(--panel2); color: var(--text); cursor: pointer;
  font-size: 15px; transition: 0.15s;
}
.btn:hover { text-decoration: none; border-color: var(--cyan); }
.btn.primary { background: linear-gradient(135deg, var(--blue), var(--cyan)); color: #04121f; border: none; }
.btn.ghost { background: transparent; }
.btn.sm { padding: 8px 14px; font-size: 13px; }

/* 表单 */
label { display: block; color: var(--muted); margin: 14px 0 6px; font-size: 14px; }
input, textarea, select {
  width: 100%; padding: 11px 13px; border-radius: 10px; border: 1px solid var(--line);
  background: #0c1428; color: var(--text); font-size: 15px;
}
input:focus, textarea:focus, select:focus { outline: none; border-color: var(--cyan); }
.note { color: var(--muted); font-size: 13px; margin-top: 8px; }
.msg { padding: 10px 14px; border-radius: 10px; margin: 12px 0; font-size: 14px; }
.msg.err { background: rgba(255,107,107,0.12); border: 1px solid var(--err); color: #ffb3b3; }
.msg.ok { background: rgba(69,212,131,0.12); border: 1px solid var(--ok); color: #aef0c8; }

/* 标签 */
.tag { display: inline-block; padding: 2px 10px; border-radius: 999px; background: #0c1428; border: 1px solid var(--line); color: var(--muted); font-size: 12px; margin: 2px; }
.pill { display: inline-block; padding: 3px 12px; border-radius: 999px; font-size: 12px; font-weight: 700; }
.pill.free { background: rgba(147,164,196,0.18); color: var(--muted); }
.pill.standard { background: rgba(77,141,255,0.18); color: var(--blue); }
.pill.pro { background: rgba(54,214,231,0.18); color: var(--cyan); }

/* 表格 */
table { width: 100%; border-collapse: collapse; font-size: 14px; }
th, td { text-align: left; padding: 10px 12px; border-bottom: 1px solid var(--line); }
th { color: var(--muted); font-weight: 600; }

/* 代码块 */
pre { background: #0c1428; border: 1px solid var(--line); border-radius: 10px; padding: 14px; overflow: auto; color: #cfe3ff; font-size: 13px; }

/* 页脚 */
.footer { border-top: 1px solid var(--line); margin-top: 40px; padding: 26px 20px; color: var(--muted); font-size: 13px; text-align: center; }
.footer .disc { max-width: 760px; margin: 10px auto 0; opacity: 0.8; }

.row { display: flex; gap: 12px; align-items: center; flex-wrap: wrap; }
.spacer { flex: 1; }
.hidden { display: none !important; }