:root {
  --bg-start: #0ea5e9; /* sky-500 */
  --bg-end: #8b5cf6;   /* violet-500 */
  --card-bg: rgba(255, 255, 255, 0.9);
  --text-color: #0f172a; /* slate-900 */
  --muted-color: #334155; /* slate-700 */
  --accent: #0ea5e9;
}
@media (prefers-color-scheme: dark) {
  :root {
    --card-bg: rgba(2, 6, 23, 0.8);
    --text-color: #e2e8f0;
    --muted-color: #94a3b8;
  }
}
* { box-sizing: border-box; }
html, body { height: 100%; }
body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen, Ubuntu, Cantarell, "Helvetica Neue", Arial, "Noto Sans SC", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  background: linear-gradient(135deg, var(--bg-start), var(--bg-end));
  display: grid;
  place-items: center;
  color: var(--text-color);
}
.card {
  width: min(720px, 92vw);
  background: var(--card-bg);
  backdrop-filter: saturate(180%) blur(16px);
  border-radius: 18px;
  box-shadow: 0 10px 25px rgba(0,0,0,0.18);
  padding: 32px 28px;
  animation: floatIn .8s ease-out;
}
.title {
  font-size: clamp(28px, 6vw, 40px);
  line-height: 1.2;
  margin: 0 0 12px 0;
  letter-spacing: 0.5px;
}
.subtitle {
  margin: 0 0 20px 0;
  font-size: clamp(16px, 3.8vw, 18px);
  color: var(--muted-color);
}
.badge {
  display: inline-block;
  padding: 6px 12px;
  border-radius: 999px;
  background: rgba(14, 165, 233, 0.12);
  color: var(--accent);
  font-weight: 600;
  font-size: 14px;
  border: 1px solid rgba(14,165,233,0.25);
}
.actions .badge {
  display: inline-block;
  text-decoration: none;
}
.footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-top: 24px;
  font-size: 14px;
  color: var(--muted-color);
}
.footer a {
  color: var(--accent);
  text-decoration: none;
  border-bottom: 1px dashed rgba(14,165,233,0.35);
}
.footer a:hover { opacity: .9; }
.links {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 16px;
}
.link-card {
  display: block;
  flex: 1 1 180px;
  min-width: 180px;
  padding: 16px;
  border-radius: 12px;
  background: rgba(255,255,255,0.6);
  text-decoration: none;
  color: var(--text-color);
  border: 1px solid rgba(0,0,0,0.04);
}
@media (prefers-color-scheme: dark) {
  .link-card {
    background: rgba(2,6,23,0.6);
    border-color: rgba(255,255,255,0.06);
  }
}
.link-card:hover { filter: brightness(1.02); }
@keyframes floatIn {
  from { opacity: 0; transform: translateY(10px); }
  to { opacity: 1; transform: translateY(0); }
}
.pdf-container {
  width: 100%;
  height: 100vh;
  overflow: auto;
  -webkit-overflow-scrolling: touch;
  overscroll-behavior: contain;
  padding: 12px 0;
}
.pdf-container iframe {
  width: 100%;
  height: calc(100vh - 24px);
  border: none;
}
@media (min-width: 800px) {
  /* 桌面端优化：更好的交互与阅读体验 */
  .pdf-container {
    height: calc(100vh - 160px);
    padding: 0;
  }
  .pdf-container iframe {
    height: 100%;
  }
}