:root {
  --bg: #ffffff;
  --fg: #14181f;
  --muted: #5b6673;
  --accent: #0b6bcb;
  --accent-dark: #084e96;
  --line: #e5e9ef;
  --card: #f7f9fc;
  --maxw: 960px;
  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --mono: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
}

* { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  font-family: var(--font);
  color: var(--fg);
  background: var(--bg);
  line-height: 1.6;
  font-size: 17px;
}

.container {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 0 20px;
}

a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }

/* Header */
.site-header {
  border-bottom: 1px solid var(--line);
  position: sticky;
  top: 0;
  background: rgba(255,255,255,0.92);
  backdrop-filter: saturate(180%) blur(8px);
  z-index: 10;
}
.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 62px;
}
.brand-mark {
  font-weight: 800;
  letter-spacing: 0.06em;
  font-size: 1.25rem;
  color: var(--fg);
}
.brand:hover { text-decoration: none; }
.site-nav { display: flex; gap: 22px; flex-wrap: wrap; }
.site-nav a { color: var(--muted); font-size: 0.95rem; font-weight: 500; }
.site-nav a:hover, .site-nav a.active { color: var(--accent); text-decoration: none; }

main.container { padding-top: 8px; padding-bottom: 40px; }

/* Hero */
.hero { padding: 64px 0 40px; border-bottom: 1px solid var(--line); }
.hero h1 { font-size: 2.4rem; line-height: 1.15; margin: 0 0 16px; letter-spacing: -0.02em; }
.hero-sub { font-size: 1.2rem; color: var(--muted); max-width: 640px; margin: 0 0 28px; }
.hero-cta { display: flex; gap: 14px; flex-wrap: wrap; }

.btn {
  display: inline-block;
  padding: 11px 20px;
  border-radius: 8px;
  font-weight: 600;
  font-size: 0.98rem;
  border: 1px solid transparent;
}
.btn:hover { text-decoration: none; }
.btn-primary { background: var(--accent); color: #fff; }
.btn-primary:hover { background: var(--accent-dark); }
.btn-ghost { border-color: var(--line); color: var(--fg); }
.btn-ghost:hover { border-color: var(--accent); color: var(--accent); }

/* Services grid */
.services-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 18px;
  padding: 44px 0;
}
.service-card {
  display: block;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 24px;
  color: var(--fg);
  transition: border-color .15s, transform .15s;
}
.service-card:hover { text-decoration: none; border-color: var(--accent); transform: translateY(-2px); }
.service-card h2 { font-size: 1.15rem; margin: 0 0 10px; }
.service-card p { color: var(--muted); font-size: 0.97rem; margin: 0 0 14px; }
.card-link { color: var(--accent); font-weight: 600; font-size: 0.95rem; }

/* Home intro + sections */
.home-intro { max-width: 680px; color: var(--fg); padding: 8px 0 24px; }
.section-title { font-size: 1.4rem; margin: 0 0 18px; }
.latest-articles { border-top: 1px solid var(--line); padding: 40px 0 8px; }

/* Topic chips nav */
.topic-chips {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 4px 0 28px;
}
.topic-chips a {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 13px;
  border: 1px solid var(--line);
  border-radius: 999px;
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--muted);
  background: var(--bg);
}
.topic-chips a:hover { text-decoration: none; border-color: var(--accent); color: var(--accent); }
.topic-chips a.active { background: var(--accent); border-color: var(--accent); color: #fff; }
.topic-chips .chip-count { font-size: 0.78rem; opacity: 0.75; }

/* Blog topic groups */
.topic-group { margin: 0 0 28px; }
.topic-group + .topic-group { border-top: 1px solid var(--line); padding-top: 20px; }
.topic-group .section-title { font-size: 1.25rem; margin: 0 0 6px; }

/* Article list */
.article-list { list-style: none; padding: 0; margin: 0 0 20px; }
.article-list li {
  display: flex;
  align-items: baseline;
  gap: 12px;
  flex-wrap: wrap;
  padding: 12px 0;
  border-bottom: 1px solid var(--line);
}
.article-list li a { font-weight: 600; font-size: 1.05rem; }
.article-list time { color: var(--muted); font-size: 0.85rem; }
.article-list .excerpt { flex-basis: 100%; color: var(--muted); font-size: 0.95rem; }

/* Content pages */
.page { max-width: 720px; padding: 40px 0; }
.page-head h1 { font-size: 2rem; letter-spacing: -0.01em; margin: 0 0 8px; }
.page-head .meta { color: var(--muted); font-size: 0.9rem; margin: 0 0 8px; }
.prose { font-size: 1.05rem; }
.prose h2 { margin-top: 34px; font-size: 1.35rem; }
.prose ul { padding-left: 22px; }
.prose li { margin: 8px 0; }
.prose code { font-family: var(--mono); background: var(--card); padding: 2px 6px; border-radius: 5px; font-size: 0.9em; }
.prose blockquote {
  border-left: 3px solid var(--accent);
  margin: 24px 0;
  padding: 4px 18px;
  color: var(--muted);
  font-style: italic;
}
.page-cta {
  margin-top: 40px;
  padding: 24px;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 12px;
}
.page-cta p { margin: 0 0 14px; font-weight: 600; }

/* Lab gallery */
.gallery {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 16px;
  margin: 28px 0 8px;
}
.gallery-item { margin: 0; }
.gallery-item a { display: block; border-radius: 10px; overflow: hidden; border: 1px solid var(--line); }
.gallery-item img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 76 / 52;
  object-fit: cover;
  transition: transform .25s ease;
}
.gallery-item a:hover img { transform: scale(1.04); }
.gallery-item figcaption { margin-top: 8px; font-size: 0.88rem; color: var(--muted); }
.muted-note { color: var(--muted); }

/* Footer */
.site-footer { border-top: 1px solid var(--line); background: var(--card); }
.footer-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
  padding: 26px 20px;
  color: var(--muted);
  font-size: 0.92rem;
}
.footer-contact .sep { margin: 0 8px; }

@media (max-width: 560px) {
  .hero h1 { font-size: 1.9rem; }
  .header-inner { height: auto; padding: 12px 0; flex-direction: column; align-items: flex-start; gap: 10px; }
}