:root {
  --bg: #0f1115;
  --card: #171a21;
  --line: #262b36;
  --text: #e6e9ef;
  --muted: #9aa4b5;
  --accent: #4ade80;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  min-height: 100vh;
  display: grid;
  place-items: center;
  padding: 24px;
  background: radial-gradient(1200px 600px at 50% -10%, #1d2430, var(--bg));
  color: var(--text);
  font: 16px/1.65 -apple-system, "Segoe UI", "Microsoft YaHei", system-ui, sans-serif;
}

/* 首页：整页只有这句问候 */
.greeting {
  margin: 0;
  font-size: clamp(32px, 8vw, 64px);
  letter-spacing: .02em;
}

/* 下面几段给 404 页用 */
.card {
  width: 100%;
  max-width: 680px;
  padding: 40px;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 16px;
}

.badge {
  display: inline-block;
  padding: 4px 12px;
  border-radius: 999px;
  background: rgba(74, 222, 128, .12);
  border: 1px solid rgba(74, 222, 128, .35);
  color: var(--accent);
  font-size: 13px;
  letter-spacing: .04em;
}

h1 { margin: 16px 0 12px; font-size: 30px; }

.lead { margin: 0 0 24px; color: #c8cfdb; }

.foot {
  margin: 28px 0 0;
  padding-top: 20px;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 14px;
}

@media (max-width: 520px) {
  .card { padding: 24px; }
  h1 { font-size: 24px; }
}