/* QNFO Publications — Unified Stylesheet */

:root {
  --bg: #fafaf8;
  --fg: #1a1a1a;
  --fg-muted: #555;
  --accent: #2a5c8a;
  --accent-hover: #1d4a6e;
  --border: #e0ddd5;
  --card-bg: #fff;
  --card-hover: #f5f3ed;
  --badge-new: #c44;
  --badge-flagship: #2a5c8a;
  --badge-edu: #3a7d44;
  --badge-synth: #8a6d2a;
  --badge-interactive: #6a3d8a;
  --radius: 8px;
  --shadow: 0 1px 3px rgba(0,0,0,0.06);
  --shadow-hover: 0 2px 8px rgba(0,0,0,0.1);
  --max-width: 1100px;
  --font-serif: 'Georgia', 'Times New Roman', serif;
  --font-sans: system-ui, -apple-system, 'Segoe UI', sans-serif;
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

body {
  font-family: var(--font-sans);
  background: var(--bg);
  color: var(--fg);
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* Header */
.site-header {
  background: var(--card-bg);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 10;
  box-shadow: var(--shadow);
}
.header-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0.75rem 1.5rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.brand {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--accent);
  text-decoration: none;
  letter-spacing: -0.01em;
}
.header-nav { display: flex; gap: 1.5rem; }
.header-nav a {
  color: var(--fg-muted);
  text-decoration: none;
  font-size: 0.875rem;
  transition: color 0.15s;
}
.header-nav a:hover { color: var(--accent); }

/* Main */
.site-main {
  flex: 1;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 3rem 1.5rem;
  width: 100%;
}
h1 { font-size: 2rem; font-weight: 700; margin-bottom: 0.5rem; }
.lede {
  font-size: 1.05rem;
  color: var(--fg-muted);
  max-width: 700px;
  margin-bottom: 2.5rem;
  line-height: 1.7;
}
.lede a { color: var(--accent); }

/* Sections */
.paper-section { margin-bottom: 3rem; }
.paper-section h2 {
  font-size: 1.25rem;
  font-weight: 600;
  margin-bottom: 1rem;
  padding-bottom: 0.5rem;
  border-bottom: 2px solid var(--border);
}

/* Paper Grid */
.paper-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 1rem;
}
.paper-card {
  display: block;
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.25rem;
  text-decoration: none;
  color: var(--fg);
  transition: box-shadow 0.15s, border-color 0.15s;
  box-shadow: var(--shadow);
}
.paper-card:hover {
  box-shadow: var(--shadow-hover);
  border-color: var(--accent);
  background: var(--card-hover);
}
.paper-card h3 {
  font-size: 1.05rem;
  font-weight: 600;
  margin-bottom: 0.25rem;
  color: var(--accent);
}
.paper-card p {
  font-size: 0.875rem;
  color: var(--fg-muted);
  line-height: 1.5;
}
.badge {
  display: inline-block;
  font-size: 0.7rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.03em;
  padding: 0.1em 0.5em;
  border-radius: 3px;
  margin-left: 0.35em;
  vertical-align: middle;
  color: #fff;
  background: var(--fg-muted);
}
.badge[data-type="new"] { background: var(--badge-new); }
.badge[data-type="flagship"] { background: var(--badge-flagship); }
.badge[data-type="educational"] { background: var(--badge-edu); }
.badge[data-type="synthesis"] { background: var(--badge-synth); }
.badge[data-type="interactive"] { background: var(--badge-interactive); }

/* Footer */
.site-footer {
  background: var(--card-bg);
  border-top: 1px solid var(--border);
  padding: 1.5rem;
  text-align: center;
  font-size: 0.8rem;
  color: var(--fg-muted);
  margin-top: auto;
}
.site-footer p { margin: 0.25rem 0; }
.site-footer a { color: var(--accent); }

/* Paper detail page */
.paper-detail {
  max-width: 750px;
  margin: 2rem auto;
  padding: 2rem;
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}
.paper-detail h1 { font-size: 1.5rem; margin-bottom: 1rem; }
.paper-detail .notice {
  background: #fef9e7;
  border: 1px solid #f0d060;
  border-radius: var(--radius);
  padding: 1rem;
  margin: 1.5rem 0;
  font-size: 0.9rem;
  color: #6a5d20;
}
.paper-detail .back-link {
  display: inline-block;
  margin-bottom: 1rem;
  color: var(--accent);
  text-decoration: none;
  font-size: 0.875rem;
}
.paper-detail .back-link:hover { text-decoration: underline; }

/* Responsive */
@media (max-width: 700px) {
  .paper-grid { grid-template-columns: 1fr; }
  h1 { font-size: 1.5rem; }
  .header-inner { flex-direction: column; gap: 0.5rem; text-align: center; }
}