:root {
  --bg: #0b0d10;
  --bg-elev: #14171c;
  --border: #242832;
  --fg: #e7ebf0;
  --fg-dim: #9aa4b2;
  --accent: #7cc4ff;
  --tag-bg: #1d2330;
  --tag-fg: #9ad0ff;
  --radius: 12px;
  --container: 960px;
}
@media (prefers-color-scheme: light) {
  :root {
    --bg: #fafbfc;
    --bg-elev: #ffffff;
    --border: #e4e7eb;
    --fg: #111418;
    --fg-dim: #55606e;
    --accent: #1f6feb;
    --tag-bg: #eef4ff;
    --tag-fg: #1f6feb;
  }
}
* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body {
  font-family: -apple-system, BlinkMacSystemFont, "Inter", "Segoe UI", Roboto, sans-serif;
  background: var(--bg);
  color: var(--fg);
  font-size: 16px;
  line-height: 1.6;
}
.container {
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 24px;
}
.site-header {
  padding: 56px 0 32px;
  border-bottom: 1px solid var(--border);
  background: var(--bg-elev);
}
.site-header h1 {
  margin: 0 0 8px;
  font-size: 32px;
  letter-spacing: -0.02em;
}
.subtitle {
  color: var(--fg-dim);
  margin: 0 0 24px;
}
#search {
  width: 100%;
  padding: 12px 16px;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  color: var(--fg);
  font-size: 15px;
  outline: none;
}
#search:focus { border-color: var(--accent); }

.grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 16px;
  padding: 32px 0;
}
.card {
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  transition: transform 0.15s ease, border-color 0.15s ease;
}
.card:hover {
  transform: translateY(-2px);
  border-color: var(--accent);
}
.card-link {
  display: block;
  padding: 20px;
  text-decoration: none;
  color: inherit;
}
.card-meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  color: var(--fg-dim);
  font-size: 13px;
  margin-bottom: 8px;
}
.card h2 {
  margin: 0 0 8px;
  font-size: 18px;
  letter-spacing: -0.01em;
}
.card p {
  margin: 0;
  color: var(--fg-dim);
  font-size: 14px;
}
.card-tags { display: flex; flex-wrap: wrap; gap: 6px; }
.tag {
  display: inline-block;
  padding: 2px 8px;
  font-size: 12px;
  border-radius: 999px;
  background: var(--tag-bg);
  color: var(--tag-fg);
}

.empty {
  grid-column: 1 / -1;
  padding: 48px;
  text-align: center;
  color: var(--fg-dim);
  border: 1px dashed var(--border);
  border-radius: var(--radius);
}

.research-header {
  padding: 32px 0 24px;
  border-bottom: 1px solid var(--border);
  background: var(--bg-elev);
}
.back {
  color: var(--accent);
  text-decoration: none;
  font-size: 14px;
}
.back:hover { text-decoration: underline; }
.research-header .meta {
  display: flex;
  align-items: center;
  gap: 12px;
  color: var(--fg-dim);
  font-size: 13px;
  margin: 16px 0 8px;
}
.research-header h1 {
  margin: 0 0 12px;
  font-size: 28px;
  letter-spacing: -0.02em;
}
.summary { color: var(--fg-dim); margin: 0 0 16px; }
.research-nav {
  display: flex;
  gap: 12px;
  font-size: 13px;
}
.research-nav a {
  color: var(--fg-dim);
  text-decoration: none;
  padding: 4px 10px;
  border: 1px solid var(--border);
  border-radius: 999px;
}
.research-nav a:hover { color: var(--accent); border-color: var(--accent); }

.research-content {
  padding: 32px 0 64px;
}
.research-content h1, .research-content h2, .research-content h3 { letter-spacing: -0.01em; }
.research-content img { max-width: 100%; border-radius: var(--radius); }
.research-content table {
  width: 100%;
  border-collapse: collapse;
  margin: 16px 0;
  font-size: 14px;
}
.research-content th, .research-content td {
  padding: 10px 12px;
  border-bottom: 1px solid var(--border);
  text-align: left;
}
.research-content code {
  background: var(--bg-elev);
  padding: 2px 6px;
  border-radius: 6px;
  font-size: 0.9em;
}
.research-content pre {
  background: var(--bg-elev);
  padding: 16px;
  border-radius: var(--radius);
  overflow-x: auto;
  border: 1px solid var(--border);
}

.site-footer {
  padding: 24px 0;
  border-top: 1px solid var(--border);
  color: var(--fg-dim);
  font-size: 13px;
  text-align: center;
}
.site-footer a { color: var(--fg-dim); }