:root {
  --bg: #ffffff;
  --bg-soft: #f7f7f5;
  --bg-card: #ffffff;
  --text: #1d1d1f;
  --text-soft: #55555a;
  --text-faint: #8a8a8f;
  --border: #ececea;
  --border-strong: #dcdcda;
  --accent: #1a1a1a;
  --accent-soft: #f0efec;
  --radius: 14px;
  --radius-sm: 9px;
  --shadow: 0 1px 2px rgba(0,0,0,0.04), 0 8px 24px rgba(0,0,0,0.04);
  --maxw: 1080px;
  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", Inter, Roboto, Helvetica, Arial, sans-serif;
  --mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: var(--font);
  color: var(--text);
  background: var(--bg);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

a { color: inherit; text-decoration: none; }

.wrap { max-width: var(--maxw); margin: 0 auto; padding: 0 24px; }

/* Header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(255,255,255,0.8);
  backdrop-filter: saturate(180%) blur(20px);
  border-bottom: 1px solid var(--border);
}
.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 60px;
}
.brand { display: flex; align-items: baseline; gap: 10px; font-weight: 600; letter-spacing: -0.02em; font-size: 16px; }
.brand .mark {
  font-weight: 600;
  font-size: 16px;
}
.brand .brand-sub { color: var(--text-faint); font-weight: 400; font-size: 13px; }
.nav-links { display: flex; gap: 4px; align-items: center; }
.nav-links a {
  padding: 7px 14px;
  border-radius: 8px;
  font-size: 14px;
  color: var(--text-soft);
  transition: background .15s, color .15s;
}
.nav-links a:hover { background: var(--bg-soft); color: var(--text); }
.nav-links a.active { color: var(--text); font-weight: 500; }
.nav-toggle { display: none; }

/* Hero */
.hero { padding: 96px 0 72px; }
.hero .eyebrow {
  display: inline-block;
  font-size: 13px;
  color: var(--text-faint);
  letter-spacing: 0.04em;
  text-transform: uppercase;
  margin-bottom: 20px;
}
.hero h1 {
  font-size: clamp(38px, 6vw, 64px);
  line-height: 1.05;
  letter-spacing: -0.03em;
  margin: 0 0 24px;
  font-weight: 640;
  max-width: 16ch;
}
.hero p.lead {
  font-size: clamp(17px, 2.2vw, 21px);
  color: var(--text-soft);
  max-width: 60ch;
  margin: 0 0 36px;
}
.hero-actions { display: flex; gap: 12px; flex-wrap: wrap; }

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 11px 20px;
  border-radius: 10px;
  font-size: 15px;
  font-weight: 500;
  border: 1px solid transparent;
  cursor: pointer;
  transition: transform .12s, background .15s, border-color .15s;
}
.btn-primary { background: var(--accent); color: #fff; }
.btn-primary:hover { transform: translateY(-1px); background: #000; }
.btn-secondary { background: var(--bg); color: var(--text); border-color: var(--border-strong); }
.btn-secondary:hover { background: var(--bg-soft); }

/* Stat row */
.stats { display: flex; gap: 48px; margin-top: 64px; flex-wrap: wrap; }
.stat .num { font-size: 30px; font-weight: 640; letter-spacing: -0.02em; }
.stat .label { font-size: 14px; color: var(--text-faint); margin-top: 2px; }

/* Section */
.section { padding: 72px 0; border-top: 1px solid var(--border); }
.section-head { margin-bottom: 40px; }
.section-head h2 { font-size: clamp(26px, 3.5vw, 34px); letter-spacing: -0.02em; margin: 0 0 10px; font-weight: 620; }
.section-head p { color: var(--text-soft); margin: 0; max-width: 56ch; font-size: 16px; }
.section-head .row { display: flex; justify-content: space-between; align-items: flex-end; gap: 24px; flex-wrap: wrap; }
.link-more { font-size: 14px; color: var(--text-soft); font-weight: 500; white-space: nowrap; }
.link-more:hover { color: var(--text); }

/* Filter bar */
.filters { display: flex; gap: 8px; flex-wrap: wrap; margin-bottom: 32px; }
.filter {
  padding: 7px 15px;
  border-radius: 999px;
  font-size: 14px;
  border: 1px solid var(--border-strong);
  background: var(--bg);
  color: var(--text-soft);
  cursor: pointer;
  transition: all .15s;
}
.filter:hover { background: var(--bg-soft); }
.filter.active { background: var(--accent); color: #fff; border-color: var(--accent); }

/* Cards grid */
.grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(320px, 1fr)); gap: 20px; }

.card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  cursor: pointer;
  transition: transform .15s, box-shadow .2s, border-color .15s;
  display: flex;
  flex-direction: column;
  min-height: 190px;
}
.card:hover { transform: translateY(-2px); box-shadow: var(--shadow); border-color: var(--border-strong); }
.card .meta { display: flex; gap: 8px; align-items: center; margin-bottom: 14px; }
.pill {
  font-size: 12px;
  padding: 3px 10px;
  border-radius: 999px;
  background: var(--accent-soft);
  color: var(--text-soft);
  font-weight: 500;
}
.pill.model { background: #eef1f6; color: #3a4a63; }
.card h3 { font-size: 18px; margin: 0 0 8px; letter-spacing: -0.01em; font-weight: 600; }
.card p { margin: 0; color: var(--text-soft); font-size: 14.5px; flex: 1; }
.card .foot { margin-top: 16px; display: flex; gap: 6px; flex-wrap: wrap; }
.tag { font-size: 12px; color: var(--text-faint); }
.tag::before { content: "#"; opacity: .5; }

/* Article cards */
.article-card .date { font-size: 13px; color: var(--text-faint); }
.article-card h3 { font-size: 19px; margin: 8px 0 8px; }

/* Modal / detail */
.overlay {
  position: fixed;
  inset: 0;
  background: rgba(20,20,22,0.4);
  backdrop-filter: blur(4px);
  z-index: 100;
  display: none;
  padding: 40px 20px;
  overflow-y: auto;
}
.overlay.open { display: block; }
.modal {
  max-width: 760px;
  margin: 0 auto;
  background: var(--bg);
  border-radius: 18px;
  box-shadow: 0 24px 80px rgba(0,0,0,0.24);
  overflow: hidden;
  animation: rise .22s ease;
}
@keyframes rise { from { opacity: 0; transform: translateY(12px); } to { opacity: 1; transform: none; } }
.modal-head {
  padding: 32px 36px 24px;
  border-bottom: 1px solid var(--border);
  position: relative;
}
.modal-head .meta { display: flex; gap: 8px; margin-bottom: 16px; flex-wrap: wrap; padding-right: 44px; }
.modal-head h2 { margin: 0 0 10px; font-size: 27px; letter-spacing: -0.02em; }
.modal-head p { margin: 0; color: var(--text-soft); }
.modal-close {
  position: absolute;
  top: 24px; right: 28px;
  width: 32px; height: 32px;
  border-radius: 8px;
  border: 1px solid var(--border-strong);
  background: var(--bg);
  cursor: pointer;
  font-size: 18px;
  line-height: 1;
  color: var(--text-soft);
  display: grid; place-items: center;
}
.modal-close:hover { background: var(--bg-soft); }
.modal-body { padding: 28px 36px 36px; }

.prompt-box {
  position: relative;
  background: var(--bg-soft);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 20px 20px 20px;
  margin: 4px 0 20px;
}
.prompt-box pre {
  margin: 0;
  font-family: var(--mono);
  font-size: 13.5px;
  line-height: 1.7;
  white-space: pre-wrap;
  color: var(--text);
}
.copy-btn {
  position: absolute;
  top: 14px; right: 14px;
  padding: 6px 13px;
  border-radius: 7px;
  font-size: 13px;
  border: 1px solid var(--border-strong);
  background: var(--bg);
  cursor: pointer;
  color: var(--text-soft);
  font-weight: 500;
  transition: all .15s;
}
.copy-btn:hover { background: var(--text); color: #fff; border-color: var(--text); }
.copy-btn.done { background: #1f7a3f; color: #fff; border-color: #1f7a3f; }

.note {
  font-size: 14.5px;
  color: var(--text-soft);
  background: #fbfaf7;
  border-left: 3px solid var(--border-strong);
  padding: 12px 16px;
  border-radius: 0 8px 8px 0;
}
.note strong { color: var(--text); font-weight: 600; }

.article-body { font-size: 16.5px; line-height: 1.75; color: #2a2a2e; }
.article-body p { margin: 0 0 20px; }

/* About */
.about-grid { display: grid; grid-template-columns: 1.4fr 1fr; gap: 48px; align-items: start; }
.about-grid h2 { font-size: 30px; letter-spacing: -0.02em; margin: 0 0 20px; }
.about-grid p { color: var(--text-soft); font-size: 16px; margin: 0 0 16px; }
.principles { list-style: none; padding: 0; margin: 0; }
.principles li { padding: 16px 0; border-bottom: 1px solid var(--border); }
.principles li:last-child { border-bottom: none; }
.principles strong { display: block; font-size: 15px; margin-bottom: 3px; }
.principles span { font-size: 14px; color: var(--text-faint); }

/* Footer */
.site-footer { border-top: 1px solid var(--border); padding: 48px 0; margin-top: 40px; color: var(--text-faint); }
.footer-inner { display: flex; justify-content: space-between; align-items: center; flex-wrap: wrap; gap: 16px; }
.footer-inner .brand { color: var(--text); }
.footer-links { display: flex; gap: 20px; font-size: 14px; }
.footer-links a:hover { color: var(--text); }
.copyright { font-size: 13px; }

/* Empty */
.empty { text-align: center; padding: 60px 0; color: var(--text-faint); }

@media (max-width: 720px) {
  .nav-links { display: none; }
  .about-grid { grid-template-columns: 1fr; gap: 32px; }
  .hero { padding: 64px 0 48px; }
  .stats { gap: 32px; }
  .modal-body, .modal-head { padding-left: 22px; padding-right: 22px; }
}