/* ==========================================================================
   RoM-Nav project page
   Design notes:
     - Serif prose on warm white. The page should read as a document.
     - One accent (ink blue), used only on links and the active selector.
     - No box-shadow anywhere. Hairline rules instead of cards.
     - Sans is reserved for structure: nav, captions, tables, labels.
   ========================================================================== */

:root {
  --paper:  #fdfcfa;
  --ink:    #1a1a1a;
  --muted:  #6b6560;
  --rule:   #d9d5cf;
  --hair:   #e8e4dd;
  --accent: #1c3f6e;
  --accent-soft: #eef2f7;

  --serif: "Source Serif 4", Charter, "Bitstream Charter", Georgia, serif;
  --sans:  "Source Sans 3", system-ui, -apple-system, "Segoe UI", Helvetica, Arial, sans-serif;
  --mono:  ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace;

  /* One column at the original media width. Prose, figures, video and tables all
     sit on it, so nothing steps outside anything else. 68rem less the 1.5rem
     gutters is a 1040 px content box; at 1.25rem that is a long line (~116
     characters), carried by generous leading. Narrow --measure alone to trade
     width for measure -- but then text and media stop matching again. */
  --measure: 68rem;
  --wide:    68rem;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --paper:  #141312;
    --ink:    #e8e4de;
    --muted:  #9a938c;
    --rule:   #3a3632;
    --hair:   #2a2724;
    --accent: #8fb3d9;
    --accent-soft: #1d2530;
  }
}
:root[data-theme="dark"] {
  --paper:  #141312;
  --ink:    #e8e4de;
  --muted:  #9a938c;
  --rule:   #3a3632;
  --hair:   #2a2724;
  --accent: #8fb3d9;
  --accent-soft: #1d2530;
}

/* -------------------------------------------------------------- base */

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

html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } }

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--serif);
  font-size: 1.25rem;
  line-height: 1.75;
  font-kerning: normal;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--accent); text-decoration: none; border-bottom: 1px solid currentColor; }
a:hover { border-bottom-width: 2px; }

h1, h2, h3 { font-weight: 600; line-height: 1.25; }

p { margin: 0 0 1.1em; }
p + p { text-indent: 0; }

sup { font-size: 0.72em; line-height: 0; vertical-align: super; }

/* -------------------------------------------------------------- layout */

.wrap  { max-width: var(--wide); margin: 0 auto; padding: 0 1.5rem; }
.prose { max-width: var(--measure); margin-left: auto; margin-right: auto; }

section { padding: 5.5rem 0 0.5rem; }

/* -------------------------------------------------------------- masthead */

.masthead { padding: 4.5rem 0 2.25rem; text-align: center; }

.masthead h1 {
  font-size: clamp(1.85rem, 4.2vw, 2.85rem);
  letter-spacing: -0.012em;
  margin: 0 auto 1.6rem;
  max-width: 36ch;
  text-wrap: balance;
}

.authors {
  font-family: var(--sans);
  font-size: 1.1875rem;
  margin: 0 auto 0.65rem;
  max-width: 44rem;
  line-height: 1.9;
}
.authors a { border-bottom-color: var(--rule); }

.affil {
  font-family: var(--sans);
  font-size: 0.9375rem;
  color: var(--muted);
  margin: 0 auto 1.35rem;
  max-width: 54rem;
  line-height: 1.7;
}

.venue {
  font-family: var(--sans);
  font-size: 0.9375rem;
  letter-spacing: 0.055em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: 1.6rem;
}

.links { display: flex; gap: 0.6rem; justify-content: center; flex-wrap: wrap; }
.links a {
  font-family: var(--sans);
  font-size: 1.0625rem;
  padding: 0.42rem 1.4rem;
  border: 1px solid var(--rule);
  border-radius: 2px;
  color: var(--ink);
  transition: border-color 0.15s, color 0.15s;
}
.links a:hover { border-color: var(--accent); color: var(--accent); }
.links a[aria-disabled="true"] { color: var(--muted); border-style: dashed; cursor: default; }
.links a[aria-disabled="true"]:hover { border-color: var(--rule); color: var(--muted); }

/* -------------------------------------------------------------- nav */

.nav {
  position: sticky; top: 0; z-index: 20;
  background: color-mix(in srgb, var(--paper) 92%, transparent);
  backdrop-filter: saturate(140%) blur(8px);
  border-bottom: 1px solid var(--hair);
  margin-top: 2.5rem;
}
.nav ul {
  display: flex; gap: 1.75rem; justify-content: center; flex-wrap: wrap;
  list-style: none; margin: 0 auto; padding: 0.8rem 1.5rem;
  max-width: var(--wide);
}
.nav a {
  font-family: var(--sans);
  font-size: 0.875rem;
  letter-spacing: 0.07em;
  text-transform: uppercase;
  color: var(--muted);
  border-bottom: 1px solid transparent;
  padding-bottom: 2px;
}
.nav a:hover { color: var(--ink); }
.nav a.current { color: var(--accent); border-bottom-color: var(--accent); }

/* -------------------------------------------------------------- headings */

.sec-head {
  max-width: var(--measure);
  margin: 0 auto 2.25rem;
  padding-bottom: 0.6rem;
  border-bottom: 1px solid var(--rule);
}
.sec-num {
  display: block;
  font-family: var(--sans);
  font-size: 0.8125rem;
  font-weight: 600;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: 0.4rem;
}
.sec-head h2 { font-size: 1.5rem; margin: 0; letter-spacing: -0.008em; }

h3.sub {
  max-width: var(--measure);
  margin: 3.5rem auto 1.1rem;
  font-family: var(--sans);
  font-size: 1.125rem;
  font-weight: 600;
  letter-spacing: 0.005em;
}
h3.sub .lt { color: var(--muted); font-weight: 400; margin-right: 0.5em; }

/* -------------------------------------------------------------- figures */

figure { margin: 3.5rem auto; max-width: var(--wide); }
figure img, figure video { display: block; width: 100%; height: auto; border: 1px solid var(--hair); border-radius: 2px; background: var(--hair); }
figure.plain img { border: none; background: none; }

figcaption {
  font-family: var(--sans);
  font-size: 0.875rem;
  line-height: 1.6;
  color: var(--muted);
  margin-top: 0.8rem;
}
figcaption b { color: var(--ink); font-weight: 600; font-variant: small-caps; letter-spacing: 0.03em; }
figcaption a { color: var(--muted); border-bottom-color: var(--rule); }
figcaption a:hover { color: var(--accent); border-bottom-color: currentColor; }

.hero-fig { margin: 0 auto 0; }
.hero-fig video { border: 1px solid var(--hair); }

.duo { display: grid; grid-template-columns: 1fr 1fr; gap: 1.25rem; }
.duo figcaption { margin-top: 0.55rem; }
@media (max-width: 40rem) { .duo { grid-template-columns: 1fr; } }

.trio { display: grid; grid-template-columns: repeat(3, 1fr); gap: 1.1rem; }
@media (max-width: 52rem) { .trio { grid-template-columns: 1fr; } }

/* -------------------------------------------------------------- selector */

.picker {
  display: flex; gap: 1.6rem; flex-wrap: wrap;
  max-width: var(--wide); margin: 0 auto 1.4rem;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid var(--hair);
}
.picker button {
  font-family: var(--sans);
  font-size: 0.9375rem;
  background: none;
  border: none;
  border-bottom: 2px solid transparent;
  color: var(--muted);
  padding: 0.2rem 0 0.35rem;
  cursor: pointer;
  letter-spacing: 0.01em;
}
.picker button:hover { color: var(--ink); }
.picker button[aria-selected="true"] { color: var(--accent); border-bottom-color: var(--accent); }
.picker .hint { margin-left: auto; font-family: var(--sans); font-size: 0.75rem; color: var(--muted); align-self: center; }
@media (max-width: 52rem) { .picker .hint { display: none; } }

/* -------------------------------------------------------------- tables */

.tbl { max-width: var(--wide); margin: 3.5rem auto; overflow-x: auto; }
.tbl table {
  width: 100%;
  border-collapse: collapse;
  font-family: var(--sans);
  font-size: 0.9375rem;
  font-variant-numeric: tabular-nums;
  border-top: 1.5px solid var(--ink);
  border-bottom: 1.5px solid var(--ink);
}
.tbl caption {
  caption-side: top;
  text-align: left;
  font-family: var(--sans);
  font-size: 0.875rem;
  line-height: 1.6;
  color: var(--muted);
  margin-bottom: 0.7rem;
  width: 100%;
}
.tbl caption b { color: var(--ink); font-weight: 600; font-variant: small-caps; letter-spacing: 0.03em; }
.tbl th, .tbl td { padding: 0.44rem 0.7rem; text-align: right; white-space: nowrap; }
.tbl th:first-child, .tbl td:first-child { white-space: normal; }
.tbl th:first-child, .tbl td:first-child { text-align: left; padding-left: 0; }
.tbl td:last-child, .tbl th:last-child { padding-right: 0; }
.tbl thead th { font-weight: 600; }
.tbl thead tr:last-child th { border-bottom: 1px solid var(--ink); }
.tbl thead tr:first-child th.grp { border-bottom: 1px solid var(--rule); text-align: center; font-weight: 400; color: var(--muted); }
.tbl tbody tr.gap td { padding-top: 1rem; }
.tbl tbody td.best { font-weight: 600; }
.tbl tbody td.na { color: var(--muted); }
.tbl .tnote {
  font-family: var(--sans);
  font-size: 0.8125rem;
  color: var(--muted);
  margin-top: 0.6rem;
  line-height: 1.6;
  width: 100%;
}

/* -------------------------------------------------------------- math */

.eq { margin: 1.5rem auto; max-width: var(--measure); overflow-x: auto; }
.katex { font-size: 1.02em; }

/* -------------------------------------------------------------- video facade */

.facade {
  position: relative; display: block; max-width: var(--wide); margin: 3rem auto 0;
  border: 1px solid var(--hair); border-radius: 2px; overflow: hidden; cursor: pointer;
  background: var(--hair);
}
.facade img { display: block; width: 100%; height: auto; }
.facade .play {
  position: absolute; inset: 0; display: grid; place-items: center;
  background: rgba(10,10,10,0.28);
  transition: background 0.18s;
}
.facade:hover .play { background: rgba(10,10,10,0.14); }
.facade .play span {
  font-family: var(--sans); font-size: 0.875rem; letter-spacing: 0.09em; text-transform: uppercase;
  color: #fff; border: 1px solid rgba(255,255,255,0.85);
  padding: 0.6rem 1.9rem; border-radius: 2px;
  background: rgba(0,0,0,0.3);
}
.facade iframe { display: block; width: 100%; aspect-ratio: 16/9; border: 0; }

/* -------------------------------------------------------------- citation */

.cite { max-width: var(--wide); margin: 1.5rem auto 0; }
.cite .bar { display: flex; align-items: baseline; justify-content: space-between; margin-bottom: 0.5rem; }
.cite .bar span { font-family: var(--sans); font-size: 0.75rem; letter-spacing: 0.09em; text-transform: uppercase; color: var(--muted); }
.cite button {
  font-family: var(--sans); font-size: 0.8125rem; background: none; border: none;
  color: var(--accent); cursor: pointer; padding: 0; border-bottom: 1px solid currentColor;
}
.cite pre {
  margin: 0; padding: 1.1rem 1.25rem; overflow-x: auto;
  font-family: var(--mono); font-size: 0.8125rem; line-height: 1.7;
  border: 1px solid var(--hair); border-radius: 2px;
  background: var(--accent-soft); color: var(--ink);
}

/* -------------------------------------------------------------- footer */

footer {
  margin-top: 6rem; padding: 2.5rem 0 4rem;
  border-top: 1px solid var(--rule);
  font-family: var(--sans); font-size: 0.8125rem; color: var(--muted);
}
footer p { max-width: var(--measure); margin: 0 auto 0.8rem; }

/* -------------------------------------------------------------- misc */

.lead { font-size: 1.06em; }
.note { color: var(--muted); font-size: 0.9375rem; }
.nowrap { white-space: nowrap; }