/* ML4WX site styles. Colors are tokens; dark mode follows the system unless the user picks a theme. */
:root {
  --bg: #f7f8fa;
  --surface: #ffffff;
  --surface-2: #eef2f6;
  --text: #16202c;
  --muted: #5b6878;
  --border: #dde3ea;
  --accent: #0b6aa2;
  --accent-soft: #e3f0f8;
  --star: #b7791f;
  --star-soft: #fbf3e2;
  --tier1: #6b46c1;
  --tier1-soft: #efe9fb;
  --code: #2f7d4f;
  --code-soft: #e5f4ea;
  --shadow: 0 1px 2px rgba(16, 32, 48, .06), 0 2px 8px rgba(16, 32, 48, .04);
  --radius: 10px;
  --font: ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --mono: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  color-scheme: light;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #0f141a; --surface: #161d25; --surface-2: #1d2630; --text: #e4e9ef; --muted: #98a4b3;
    --border: #2a3542; --accent: #5ab4e8; --accent-soft: #15324a; --star: #f0b54a; --star-soft: #3a2c12;
    --tier1: #b39af0; --tier1-soft: #2c2347; --code: #6fd39a; --code-soft: #16342a;
    --shadow: 0 1px 2px rgba(0, 0, 0, .3); color-scheme: dark;
  }
}
:root[data-theme="dark"] {
  --bg: #0f141a; --surface: #161d25; --surface-2: #1d2630; --text: #e4e9ef; --muted: #98a4b3;
  --border: #2a3542; --accent: #5ab4e8; --accent-soft: #15324a; --star: #f0b54a; --star-soft: #3a2c12;
  --tier1: #b39af0; --tier1-soft: #2c2347; --code: #6fd39a; --code-soft: #16342a;
  --shadow: 0 1px 2px rgba(0, 0, 0, .3); color-scheme: dark;
}

* { box-sizing: border-box; }
[hidden] { display: none !important; }
html { -webkit-text-size-adjust: 100%; }
body { margin: 0; background: var(--bg); color: var(--text); font: 16px/1.55 var(--font); }
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }
h1, h2, h3 { line-height: 1.25; }
h2 { font-size: 1.25rem; margin: 2rem 0 .8rem; }
code { font-family: var(--mono); font-size: .9em; background: var(--surface-2); padding: .1em .35em; border-radius: 4px; }
.wrap { max-width: 1120px; margin: 0 auto; padding: 0 16px; }
.muted { color: var(--muted); }
.sr-only { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; }
.skip { position: absolute; left: -999px; }
.skip:focus { left: 16px; top: 8px; background: var(--surface); padding: 6px 10px; z-index: 10; }

/* header / footer */
.top { background: var(--surface); border-bottom: 1px solid var(--border); position: sticky; top: 0; z-index: 5; }
.top-inner { display: flex; align-items: center; gap: 20px; min-height: 56px; flex-wrap: wrap; }
.brand { display: flex; align-items: center; gap: 8px; font-weight: 750; letter-spacing: .02em; color: var(--text); font-size: 1.1rem; }
.brand:hover { text-decoration: none; }
.nav { display: flex; gap: 4px; flex-wrap: wrap; flex: 1; }
.nav a { color: var(--muted); padding: 6px 10px; border-radius: 6px; font-size: .95rem; }
.nav a:hover, .nav a[aria-current] { color: var(--text); background: var(--surface-2); text-decoration: none; }
.theme { background: none; border: 1px solid var(--border); color: var(--muted); border-radius: 8px; padding: 6px 8px; cursor: pointer; display: flex; }
.foot { border-top: 1px solid var(--border); margin-top: 64px; padding: 24px 0; color: var(--muted); font-size: .9rem; }
.foot-inner { display: flex; justify-content: space-between; gap: 12px; flex-wrap: wrap; }

/* home */
.hero { padding: 48px 0 16px; }
.hero h1 { font-size: clamp(1.8rem, 4vw, 2.6rem); margin: 0 0 12px; letter-spacing: -.01em; }
.lede { color: var(--muted); font-size: 1.08rem; max-width: 760px; margin: 0 0 20px; }
.hero-search { display: flex; gap: 8px; max-width: 760px; }
.hero-search input, .search-row input {
  flex: 1; min-width: 0; font: inherit; padding: 12px 14px; border-radius: var(--radius);
  border: 1px solid var(--border); background: var(--surface); color: var(--text);
}
.hero-search input:focus, .search-row input:focus { outline: 2px solid var(--accent); outline-offset: 1px; }
.hero-search button, .btn {
  font: inherit; border: 1px solid var(--border); background: var(--surface); color: var(--text);
  padding: 8px 14px; border-radius: 8px; cursor: pointer; display: inline-block;
}
.hero-search button { background: var(--accent); border-color: var(--accent); color: #fff; padding: 0 18px; font-weight: 600; }
.btn:hover { border-color: var(--accent); text-decoration: none; }
.stats { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 12px; max-width: 760px; margin: 28px 0 0; }
.stats div { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 12px 14px; }
.stats dt { color: var(--muted); font-size: .8rem; text-transform: uppercase; letter-spacing: .05em; }
.stats dd { margin: 2px 0 0; font-size: 1.4rem; font-weight: 700; font-variant-numeric: tabular-nums; }
.notice { background: var(--accent-soft); border-radius: var(--radius); padding: 10px 14px; margin: 24px 0 0; }
.sec-head { display: flex; justify-content: space-between; align-items: baseline; gap: 12px; margin-top: 40px; }
.sec-head h2 { margin: 0 0 12px; }
.group { font-size: .85rem; text-transform: uppercase; letter-spacing: .06em; color: var(--muted); margin: 20px 0 8px; }
.topic-grid { list-style: none; padding: 0; margin: 0; display: grid; grid-template-columns: repeat(auto-fill, minmax(240px, 1fr)); gap: 8px; }
.topic-grid a, .org-list a {
  display: flex; justify-content: space-between; gap: 8px; padding: 10px 12px; border-radius: 8px;
  background: var(--surface); border: 1px solid var(--border); color: var(--text);
}
.topic-grid a:hover, .org-list a:hover { border-color: var(--accent); text-decoration: none; }
.topic-grid b, .org-list b { color: var(--muted); font-weight: 600; font-variant-numeric: tabular-nums; }

/* cards */
.grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(320px, 1fr)); gap: 12px; }
.list { display: grid; gap: 10px; }
.card { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 14px 16px; box-shadow: var(--shadow); }
.card.is-hl { border-left: 3px solid var(--star); }
.card-title { font-size: 1.02rem; margin: 0 0 4px; }
.card-title a { color: var(--text); }
.star { color: var(--star); margin-right: 4px; }
.card-meta { color: var(--muted); font-size: .88rem; margin: 0 0 6px; }
.card-summary { margin: 0 0 8px; font-size: .95rem; }
.excerpt { color: var(--muted); font-size: .88rem; margin: 0 0 6px; }
.excerpt mark { background: var(--star-soft); color: inherit; padding: 0 2px; }
.dot { opacity: .6; margin: 0 2px; }
.chips { display: flex; flex-wrap: wrap; gap: 6px; margin: 0; }
.chip { font-size: .78rem; padding: 2px 8px; border-radius: 999px; background: var(--surface-2); color: var(--muted); }
.chip-topic { background: var(--accent-soft); color: var(--accent); }
.chip-org.tier1 { background: var(--tier1-soft); color: var(--tier1); }
.chip-code { background: var(--code-soft); color: var(--code); }

/* pages */
.page-title { font-size: clamp(1.6rem, 3vw, 2.1rem); margin: 32px 0 8px; }
.crumbs { margin: 28px 0 0; font-size: .9rem; display: flex; gap: 10px; align-items: center; flex-wrap: wrap; }
.actions { display: flex; gap: 8px; flex-wrap: wrap; margin: 12px 0; }
.badge, .badge-hl { font-size: .78rem; padding: 2px 8px; border-radius: 999px; background: var(--surface-2); color: var(--muted); }
.badge-hl { background: var(--star-soft); color: var(--star); font-weight: 600; }
.paper { max-width: 820px; }
.paper h1 { font-size: clamp(1.5rem, 3vw, 2rem); margin: 10px 0 8px; }
.authors { margin: 0 0 4px; }
.paper-meta { color: var(--muted); margin: 0 0 8px; }
.why, .tldr { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 12px 14px; }
.why { border-left: 3px solid var(--star); }
.abstract { text-align: justify; hyphens: auto; }
.facets { display: grid; grid-template-columns: max-content 1fr; gap: 6px 16px; margin: 0; }
.facets dt { color: var(--muted); }
.facets dd { margin: 0; overflow-wrap: anywhere; }
.fineprint { color: var(--muted); font-size: .85rem; margin-top: 32px; }
.topic-cards { display: grid; grid-template-columns: repeat(auto-fill, minmax(300px, 1fr)); gap: 12px; }
.topic-card { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 14px 16px; }
.topic-card h3 { margin: 0 0 6px; font-size: 1.05rem; }
.topic-card p { margin: 0 0 6px; font-size: .93rem; }
.topic-card.is-later { opacity: .7; }
.org-list { list-style: none; padding: 0; display: grid; grid-template-columns: repeat(auto-fill, minmax(300px, 1fr)); gap: 8px; }
.tier { color: var(--tier1); font-weight: 600; }
.years { display: flex; align-items: flex-end; gap: 4px; height: 120px; margin: 16px 0 28px; flex-wrap: wrap; }
.years .bar { flex: 1; min-width: 14px; height: 100px; display: flex; flex-direction: column; justify-content: flex-end; align-items: center; }
.years .bar span { width: 100%; background: var(--accent); border-radius: 3px 3px 0 0; min-height: 2px; opacity: .85; }
.years .bar small { color: var(--muted); font-size: .7rem; margin-top: 2px; }
.years figcaption { width: 100%; font-size: .8rem; }
.digest-list { list-style: none; padding: 0; }
.digest-list li { padding: 8px 0; border-bottom: 1px solid var(--border); display: flex; gap: 12px; flex-wrap: wrap; }
.prose { max-width: 820px; }
.prose h1 { margin-top: 28px; }
.prose li { margin: 6px 0; }

/* explore */
.explore { display: grid; grid-template-columns: 260px minmax(0, 1fr); gap: 24px; align-items: start; }
.facets-panel { position: sticky; top: 72px; max-height: calc(100vh - 88px); overflow: auto; background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 12px 14px; }
.facets-head { display: flex; justify-content: space-between; align-items: baseline; }
.facets-head h2 { margin: 0 0 8px; font-size: 1rem; }
.link { background: none; border: 0; color: var(--accent); cursor: pointer; font: inherit; font-size: .88rem; padding: 0; }
.facets-panel details { border-top: 1px solid var(--border); padding: 8px 0; }
.facets-panel summary { cursor: pointer; font-weight: 600; font-size: .92rem; }
.facets-panel ul { list-style: none; padding: 0; margin: 6px 0 0; max-height: 260px; overflow: auto; }
.facets-panel li { display: grid; grid-template-columns: auto 1fr auto; gap: 6px; align-items: start; font-size: .88rem; padding: 2px 0; }
.facets-panel li label { cursor: pointer; }
.facets-panel .n { color: var(--muted); font-variant-numeric: tabular-nums; }
.pill { background: var(--accent); color: #fff; border-radius: 999px; font-size: .72rem; padding: 0 6px; margin-left: 4px; }
.search-row { display: flex; gap: 10px; align-items: center; margin: 8px 0 16px; flex-wrap: wrap; }
.results #count { margin-top: 0; }
.sort { color: var(--muted); font-size: .9rem; display: flex; gap: 6px; align-items: center; }
.sort select { font: inherit; padding: 8px; border-radius: 8px; border: 1px solid var(--border); background: var(--surface); color: var(--text); }
#more { margin: 16px 0; }

@media (max-width: 760px) {
  .top-inner { gap: 4px 12px; padding-top: 8px; }
  .brand { flex: 1; }
  .nav { order: 3; flex: 0 0 100%; flex-wrap: nowrap; overflow-x: auto; margin: 0 -8px; padding-bottom: 6px; }
  .nav a { white-space: nowrap; }
  .stats { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .explore { grid-template-columns: 1fr; }
  .facets-panel { position: static; max-height: none; }
  .hero { padding-top: 28px; }
  .grid { grid-template-columns: 1fr; }
}