:root {
  --bg: #0b1020;
  --bg-soft: #121a33;
  --fg: #e8ecf6;
  --muted: #9aa6c2;
  --card: rgba(255, 255, 255, 0.04);
  --card-border: rgba(255, 255, 255, 0.08);
  --card-hover: rgba(255, 255, 255, 0.08);
  --primary: #4f7cff;
  --shadow: 0 10px 30px rgba(0, 0, 0, 0.35);
  color-scheme: dark;
}

@media (prefers-color-scheme: light) {
  :root {
    --bg: #f5f7fb;
    --bg-soft: #ffffff;
    --fg: #1a2236;
    --muted: #5b6785;
    --card: #ffffff;
    --card-border: #e6eaf2;
    --card-hover: #f0f4ff;
    --shadow: 0 10px 30px rgba(20, 30, 60, 0.08);
    color-scheme: light;
  }
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  min-height: 100%;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", Roboto, Helvetica, Arial, sans-serif;
  background:
    radial-gradient(1200px 600px at 80% -10%, rgba(79, 124, 255, 0.18), transparent 60%),
    radial-gradient(900px 500px at 0% 110%, rgba(139, 92, 246, 0.14), transparent 55%),
    var(--bg);
  color: var(--fg);
  line-height: 1.55;
  display: flex;
  flex-direction: column;
}

.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 20px clamp(16px, 5vw, 48px);
}

.brand { display: flex; align-items: center; gap: 12px; }

.logo {
  width: 34px; height: 34px;
  display: grid; place-items: center;
  border-radius: 9px;
  background: linear-gradient(135deg, var(--primary), #8b5cf6);
  color: #fff; font-weight: 800;
  box-shadow: var(--shadow);
}

.brand-name { font-weight: 700; letter-spacing: 0.3px; font-size: 18px; }

.session { display: flex; align-items: center; gap: 12px; min-height: 34px; }
.session-hint { color: var(--muted); font-size: 14px; }
.session-user { font-size: 14px; }
.session-user b { color: var(--fg); }

.hero {
  flex: 1;
  width: 100%;
  max-width: 1080px;
  margin: 0 auto;
  padding: clamp(24px, 6vw, 64px) clamp(16px, 5vw, 48px);
}

.hero-title {
  font-size: clamp(28px, 5vw, 46px);
  line-height: 1.15;
  margin: 0 0 10px;
  font-weight: 800;
}

.hero-sub { color: var(--muted); margin: 0 0 40px; font-size: clamp(15px, 2vw, 18px); }

.grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 18px;
}

.card {
  display: flex;
  gap: 16px;
  padding: 20px;
  border-radius: 16px;
  background: var(--card);
  border: 1px solid var(--card-border);
  text-decoration: none;
  color: inherit;
  box-shadow: var(--shadow);
  transition: transform 0.16s ease, background 0.16s ease, border-color 0.16s ease;
}

.card:hover,
.card:focus-visible {
  transform: translateY(-3px);
  background: var(--card-hover);
  border-color: rgba(79, 124, 255, 0.45);
  outline: none;
}

.card-icon {
  flex: 0 0 auto;
  width: 48px; height: 48px;
  border-radius: 12px;
  display: grid; place-items: center;
  font-weight: 800; font-size: 22px; color: #fff;
  background: linear-gradient(135deg, var(--accent, var(--primary)), color-mix(in srgb, var(--accent, var(--primary)) 60%, #000));
}

.card-body { min-width: 0; }
.card-title { margin: 0 0 4px; font-size: 17px; font-weight: 700; }
.card-desc { margin: 0 0 8px; color: var(--muted); font-size: 14px; }
.card-host { font-size: 12px; color: var(--primary); opacity: 0.9; word-break: break-all; }

.btn {
  display: inline-block;
  padding: 7px 14px;
  border-radius: 999px;
  font-size: 14px;
  text-decoration: none;
  border: 1px solid transparent;
  cursor: pointer;
}
.btn-primary { background: var(--primary); color: #fff; }
.btn-primary:hover { filter: brightness(1.08); }
.btn-ghost { background: transparent; color: var(--fg); border-color: var(--card-border); }
.btn-ghost:hover { background: var(--card-hover); }

.site-footer {
  padding: 24px clamp(16px, 5vw, 48px);
  color: var(--muted);
  font-size: 13px;
  text-align: center;
}

@media (max-width: 480px) {
  .card { flex-direction: column; }
}