:root {
  --bg: #f6f3ee;
  --surface: #fffdf8;
  --text: #1f2937;
  --muted: #6b7280;
  --brand: #0ea5a4;
  --line: #e5e7eb;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  min-height: 100vh;
  font-family: "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  color: var(--text);
  background: linear-gradient(180deg, #f2f9ff 0%, #e7f3ff 48%, #d8ecff 100%);
  background-attachment: fixed;
}

.container {
  width: min(980px, 92vw);
  margin: 0 auto;
}

.site-header {
  position: fixed;
  left: 0;
  top: 0;
  bottom: 0;
  width: 220px;
  background: rgba(255, 255, 255, 0.85);
  backdrop-filter: blur(8px);
  border-right: 1px solid var(--line);
  z-index: 10;
}

.nav {
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding: 18px 14px;
}

.nav a {
  text-decoration: none;
  color: var(--text);
  padding: 10px 12px;
  border-radius: 10px;
  border: 1px solid #e2e8f0;
  background: #ffffff;
}

.nav a:hover,
.nav a.active {
  border-color: var(--brand);
  color: #0f766e;
  background: #ecfeff;
}

main {
  padding: 28px 0 40px;
  margin-left: 220px;
}

.card {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 18px;
  box-shadow: 0 8px 22px rgba(0, 0, 0, 0.06);
}

h1, h2, h3 { margin-top: 0; }

.grid-2 {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
}

.badge {
  display: inline-block;
  padding: 4px 10px;
  border-radius: 999px;
  background: #ecfeff;
  color: #0f766e;
  font-size: 13px;
}

.media-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
}

img, video {
  width: 100%;
  border-radius: 10px;
  border: 1px solid var(--line);
  background: #f9fafb;
}

input, button {
  font: inherit;
}

input {
  width: 100%;
  border: 1px solid #cbd5e1;
  border-radius: 10px;
  padding: 10px 12px;
}

button {
  border: 0;
  border-radius: 10px;
  padding: 10px 14px;
  background: var(--brand);
  color: white;
  font-weight: 600;
  cursor: pointer;
}

.result {
  margin-top: 12px;
  background: #f8fafc;
  border: 1px dashed #cbd5e1;
  border-radius: 10px;
  padding: 12px;
  min-height: 58px;
}

small, .muted { color: var(--muted); }

@media (max-width: 768px) {
  .site-header {
    position: static;
    width: 100%;
    border-right: 0;
    border-bottom: 1px solid var(--line);
  }

  .nav {
    flex-direction: row;
    flex-wrap: wrap;
    padding: 14px 0;
  }

  .site-header .container {
    width: min(980px, 92vw);
    margin: 0 auto;
  }

  main { margin-left: 0; }
  .grid-2, .media-grid { grid-template-columns: 1fr; }
}

.site-header .container {
  width: 100%;
  margin: 0;
}