:root {
  --bg: #0f1115;
  --bg-2: #161a22;
  --card: #1b2029;
  --text: #e8eaed;
  --muted: #9aa3b2;
  --accent: #6ea8fe;
  --border: #2a3140;
}

@media (prefers-color-scheme: light) {
  :root {
    --bg: #f5f7fb;
    --bg-2: #eef1f7;
    --card: #ffffff;
    --text: #1b2029;
    --muted: #5b6675;
    --accent: #2f6fed;
    --border: #e2e6ee;
  }
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 24px;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", Roboto, Helvetica, Arial, sans-serif;
  color: var(--text);
  background: radial-gradient(1200px 600px at 50% -10%, var(--bg-2), var(--bg));
}

/* 右上角固定按钮 */
.top-btn {
  position: fixed;
  top: 18px;
  right: 18px;
  padding: 8px 16px;
  font-size: 14px;
  font-weight: 600;
  text-decoration: none;
  color: var(--text);
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 999px;
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.18);
  transition: transform 0.15s ease, border-color 0.15s ease, color 0.15s ease;
}

.top-btn:hover {
  transform: translateY(-1px);
  border-color: var(--accent);
  color: var(--accent);
}

.card {
  width: 100%;
  max-width: 420px;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 20px;
  padding: 40px 28px 28px;
  text-align: center;
  box-shadow: 0 12px 40px rgba(0, 0, 0, 0.25);
}

.avatar {
  width: 88px;
  height: 88px;
  margin: 0 auto 16px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 38px;
  font-weight: 700;
  color: #fff;
  background: linear-gradient(135deg, var(--accent), #b07cff);
}

h1 {
  margin: 0 0 6px;
  font-size: 26px;
}

.tagline {
  margin: 0 0 26px;
  color: var(--muted);
  font-size: 15px;
  line-height: 1.5;
}

.links {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.link {
  display: block;
  padding: 13px 16px;
  font-size: 15px;
  font-weight: 600;
  text-decoration: none;
  color: var(--text);
  background: var(--bg-2);
  border: 1px solid var(--border);
  border-radius: 12px;
  transition: transform 0.15s ease, border-color 0.15s ease, color 0.15s ease;
}

.link:hover {
  transform: translateY(-2px);
  border-color: var(--accent);
  color: var(--accent);
}

.foot {
  margin-top: 26px;
  font-size: 13px;
  color: var(--muted);
}