:root {
  --bg: #fcfbf8;
  --bg-elev: #ffffff;
  --bg-sunken: #f4f2ed;
  --fg: #1f1d19;
  --muted: #6c6861;
  --line: #e7e3da;
  --line-strong: #d3cdc1;
  --accent: #2d4a9b;
  --accent-soft: #edf0f7;
  --tight: #2f6f4a;
  --tight-soft: #e6f1ea;
  --near: #96661c;
  --near-soft: #f8f0e0;
  --gap: #a83a35;
  --gap-soft: #f8e8e6;
  --unknown: #85817a;
  --unknown-soft: #ecebe6;
  --stronger: #27609f;
  --stronger-soft: #e4eef9;
  --weaker: #b4531d;
  --weaker-soft: #fcebdf;
  --serif: "Source Serif 4", Georgia, "Times New Roman", serif;
  --sans: Inter, system-ui, -apple-system, "Segoe UI", sans-serif;
  --mono: ui-monospace, SFMono-Regular, Menlo, monospace;
  --radius: 8px;
  --radius-sm: 6px;
  --shadow: none;
  --measure: 75ch;
  /* figures: edges and outlines need >= 3:1 against the panel; lattices and grids stay in the background */
  --fig-ink: #857f74;
  --fig-faint: #dcd7cd;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #16171a; --bg-elev: #1c1d21; --bg-sunken: #202227; --fg: #e6e3dc; --muted: #a29e96; --line: #2c2e34; --line-strong: #3d4048; --fig-ink: #7d818b; --fig-faint: #34373e;
    --accent: #a3b4ec; --accent-soft: #232a3d;
    --tight: #74cf9b; --tight-soft: #1d3327; --near: #e5b45e; --near-soft: #3a2f16;
    --gap: #f08a8a; --gap-soft: #3d1f1f; --unknown: #9a968f; --unknown-soft: #2a2d33;
    --stronger: #86b6ea; --stronger-soft: #1d2d3f; --weaker: #f0a070; --weaker-soft: #3b271a;
    --shadow: none;
    color-scheme: dark;
  }
}
:root[data-theme="dark"] {
  --bg: #16171a; --bg-elev: #1c1d21; --bg-sunken: #202227; --fg: #e6e3dc; --muted: #a29e96; --line: #2c2e34; --line-strong: #3d4048; --fig-ink: #7d818b; --fig-faint: #34373e;
  --accent: #a3b4ec; --accent-soft: #232a3d;
  --tight: #74cf9b; --tight-soft: #1d3327; --near: #e5b45e; --near-soft: #3a2f16;
  --gap: #f08a8a; --gap-soft: #3d1f1f; --unknown: #9a968f; --unknown-soft: #2a2d33;
  --stronger: #86b6ea; --stronger-soft: #1d2d3f; --weaker: #f0a070; --weaker-soft: #3b271a;
  --shadow: none;
  color-scheme: dark;
}

/* ---------- base ---------- */
* { box-sizing: border-box; min-width: 0; }
html { -webkit-text-size-adjust: 100%; }
body { margin: 0; background: var(--bg); color: var(--fg); font-family: var(--sans); font-size: 15px; line-height: 1.55; }
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }
h1, h2, h3, h4 { font-family: var(--serif); font-weight: 600; line-height: 1.2; margin: 0 0 .5rem; overflow-wrap: anywhere; }
h1 { font-size: 2.1rem; letter-spacing: -.01em; }
h2 { font-size: 1.45rem; margin-top: 1.8rem; }
h3 { font-size: 1.12rem; margin-top: 1.3rem; }
p { margin: .5rem 0 .9rem; }
.lead { font-size: 1.02rem; max-width: 78ch; }
code { font-family: var(--mono); font-size: .9em; background: var(--unknown-soft); padding: .05em .3em; border-radius: 4px; }
.muted { color: var(--muted); }
.small { font-size: .86rem; }
hr { border: 0; border-top: 1px solid var(--line); margin: 1.5rem 0; }
table { border-collapse: collapse; width: 100%; }
th, td { text-align: left; vertical-align: top; padding: .5rem .6rem; border-bottom: 1px solid var(--line); }
th { font-size: .76rem; text-transform: uppercase; letter-spacing: .05em; color: var(--muted); font-weight: 600; }
.katex { font-size: 1.02em; }
.prose p:last-child { margin-bottom: 0; }

/* eyebrow section labels */
.eyebrow { font-family: var(--sans); font-size: .76rem; font-weight: 600; text-transform: uppercase; letter-spacing: .07em; color: var(--muted); margin: 0 0 .7rem; }
.eyebrow .muted { font-weight: 400; text-transform: none; letter-spacing: 0; }
.panel .eyebrow + .chips { margin-bottom: .2rem; }
.panel > .eyebrow:not(:first-child) { margin-top: 1.3rem; }

/* ---------- chrome ---------- */
.topbar { display: flex; align-items: center; justify-content: space-between; gap: 1rem; padding: .75rem 16px; border-bottom: 1px solid var(--line); background: color-mix(in srgb, var(--bg-elev) 88%, transparent); backdrop-filter: blur(8px); position: sticky; top: env(safe-area-inset-top, 0px); z-index: 10; }
.brand { font-family: var(--serif); font-weight: 600; font-size: 1.1rem; color: var(--fg); }
.topbar nav { display: flex; flex-wrap: wrap; gap: .3rem 1.1rem; font-size: .9rem; min-width: 0; }
.topbar nav a { color: var(--muted); }
.topbar nav a:hover { color: var(--fg); text-decoration: none; }
.container { max-width: 1280px; margin: 0 auto; padding: 1.5rem 16px 3rem; }
.footer { border-top: 1px solid var(--line); padding: 1.2rem 16px; color: var(--muted); font-size: .84rem; text-align: center; }

.hero { padding: .8rem 0 1.2rem; }
.hero h1 { font-size: 2.5rem; }
.hero .tagline { font-size: 1.12rem; color: var(--muted); max-width: 60ch; }
.stats { display: flex; flex-wrap: wrap; gap: .6rem; margin: 1rem 0; }
.stat { background: var(--bg-elev); border: 1px solid var(--line); border-radius: var(--radius-sm); padding: .5rem .9rem; min-width: 7rem; }
.stat b { display: block; font-size: 1.35rem; font-family: var(--serif); }
.stat span { font-size: .78rem; color: var(--muted); }

.cards { display: grid; grid-template-columns: repeat(auto-fill, minmax(250px, 1fr)); gap: .9rem; margin: .8rem 0; }
.card { display: block; background: var(--bg-elev); border: 1px solid var(--line); border-radius: var(--radius); padding: .95rem 1.05rem; color: var(--fg); box-shadow: var(--shadow); overflow: hidden; }
.card:hover { text-decoration: none; border-color: var(--accent); }
.card h3 { margin: 0 0 .35rem; font-size: 1.05rem; }
.card .summary { color: var(--muted); font-size: .88rem; margin: .35rem 0 .55rem; }
.card .chips { margin: .1rem 0 .3rem; }

/* ---------- chips and badges ---------- */
.chips { display: flex; flex-wrap: wrap; gap: .35rem; max-width: 100%; }
.chips.tiny { gap: .28rem; }
.chip { display: inline-block; font-size: .78rem; line-height: 1.3; padding: .2rem .6rem; border-radius: 999px; border: 1px solid var(--line); background: var(--bg-elev); color: var(--fg); max-width: 100%; white-space: normal; overflow-wrap: anywhere; text-align: left; }
.chip .ax, .chip b { margin-right: .3em; }
.chips.tiny .chip { font-size: .74rem; padding: .14rem .5rem; }
.chip .ax { color: var(--muted); }
.chip .ax::after { content: ":"; }
.chip b { font-weight: 700; }
.chip.stronger { background: var(--stronger-soft); border-color: transparent; color: var(--stronger); }
.chip.weaker { background: var(--weaker-soft); border-color: transparent; color: var(--weaker); }
.chip.base { background: var(--unknown-soft); border-color: transparent; color: var(--muted); }
.chip.base .ax { color: var(--muted); }
.chip.changed { outline: 2px solid currentColor; outline-offset: -1px; font-weight: 600; }
.chip.changed .ax { color: inherit; opacity: .8; }
.chip.assume { background: var(--accent-soft); border-color: transparent; color: var(--accent); }
.chip .katex { font-size: .95em; white-space: nowrap; }

.badge { display: inline-block; font-size: .7rem; font-weight: 600; letter-spacing: .04em; text-transform: uppercase; padding: .14rem .5rem; border-radius: 6px; vertical-align: middle; white-space: nowrap; }
.badge.tight { background: var(--tight-soft); color: var(--tight); }
.badge.near { background: var(--near-soft); color: var(--near); }
.badge.gap { background: var(--gap-soft); color: var(--gap); }
.badge.unknown { background: var(--unknown-soft); color: var(--unknown); }
.badge.impossible { background: var(--fg); color: var(--bg); }
.badge.introductory { background: var(--accent-soft); color: var(--accent); }
.badge.best { background: var(--tight-soft); color: var(--tight); }
.badge.other { background: var(--unknown-soft); color: var(--unknown); }
.badge.own { background: var(--accent-soft); color: var(--accent); }
.badge.verified { background: var(--tight-soft); color: var(--tight); }
.badge.draft { background: var(--near-soft); color: var(--near); }

.dots { display: inline-flex; gap: .25rem; vertical-align: middle; flex: none; }
.dot { width: .58rem; height: .58rem; border-radius: 50%; display: inline-block; background: var(--unknown); flex: none; }
.dot.tight { background: var(--tight); } .dot.near { background: var(--near); } .dot.gap { background: var(--gap); } .dot.impossible { background: var(--fg); }

.strip { display: flex; flex-wrap: wrap; gap: .4rem; margin: .2rem 0 .8rem; }
.pill { display: inline-flex; align-items: center; gap: .4rem; font-size: .8rem; font-weight: 500; padding: .22rem .65rem; border-radius: 999px; background: var(--bg-sunken); border: 1px solid var(--line); }
.pill.tight { color: var(--tight); } .pill.near { color: var(--near); } .pill.gap { color: var(--gap); } .pill.impossible { color: var(--fg); } .pill.unknown { color: var(--muted); }

/* ---------- problem statement ---------- */
details.statement { background: var(--bg-elev); border: 1px solid var(--line); border-radius: var(--radius); box-shadow: var(--shadow); margin: .4rem 0 1.3rem; }
details.statement summary { cursor: pointer; list-style: none; display: flex; justify-content: space-between; align-items: center; gap: 1rem; padding: .8rem 1.2rem; font-family: var(--serif); font-weight: 600; font-size: 1.05rem; }
details.statement summary::-webkit-details-marker { display: none; }
details.statement summary .hint { font-family: var(--sans); font-weight: 400; font-size: .78rem; color: var(--muted); text-transform: uppercase; letter-spacing: .05em; }
details.statement[open] summary { border-bottom: 1px solid var(--line); }
details.statement .statement-body { padding: .6rem 1.2rem .4rem; }

/* ---------- layout ---------- */
.layout { display: grid; grid-template-columns: 290px minmax(0, 1fr); gap: 1.5rem; align-items: start; }
.sidebar { position: sticky; top: 4rem; max-height: calc(100vh - 4.6rem); overflow: auto; padding-right: .3rem; scrollbar-width: thin; }
.sidenav > summary { list-style: none; cursor: default; }
.sidenav > summary::-webkit-details-marker { display: none; }
.sidehead { display: flex; align-items: baseline; justify-content: space-between; gap: .5rem; margin: .2rem 0 .5rem; }
.sidehead .current { display: none; }
.sidebar h4 { font-family: var(--sans); font-size: .74rem; text-transform: uppercase; letter-spacing: .06em; color: var(--muted); margin: 0; }
.sidebar .maplink { font-size: .8rem; white-space: nowrap; }
.tree, .tree ul { list-style: none; margin: 0; padding: 0; }
.tree ul { margin-left: .7rem; border-left: 1px solid var(--line-strong); padding-left: .45rem; }
.tree li { margin: .1rem 0; }
.tree a { display: flex; align-items: center; justify-content: space-between; gap: .4rem; padding: .3rem .55rem; border-radius: 7px; color: var(--fg); font-size: .86rem; line-height: 1.3; }
.tree a .t { display: block; min-width: 0; }
.tree a:hover { background: var(--accent-soft); text-decoration: none; }
.tree a.active { background: var(--accent); color: #fff; }
.tree a.active .dot { outline: 1px solid rgba(255,255,255,.7); }
.tree .delta { display: block; color: var(--muted); font-size: .74rem; line-height: 1.25; margin-top: .05rem; }
.tree a.active .delta { color: rgba(255,255,255,.82); }

.crumbs { font-size: .86rem; color: var(--muted); margin-bottom: .45rem; display: flex; flex-wrap: wrap; gap: .3rem; align-items: center; }
.crumbs a { color: var(--muted); }
.crumbs .sep { opacity: .5; }

.panel { background: var(--bg-elev); border: 1px solid var(--line); border-radius: var(--radius); padding: 1.15rem 1.35rem; box-shadow: var(--shadow); overflow: hidden; }
.panel + .panel { margin-top: 1rem; }
.panel > h2:first-child { margin-top: 0; }
.panel.head h2 { margin: 0; font-size: 1.6rem; }
.section-title { display: flex; align-items: center; justify-content: space-between; gap: 1rem; margin-bottom: .5rem; }

/* ---------- what is known ---------- */
.known { padding: 1rem 0; border-top: 1px solid var(--line); }
.known:first-of-type { border-top: 0; padding-top: 0; }
.known:last-child { padding-bottom: .2rem; }
.kname { font-weight: 600; font-family: var(--serif); font-size: 1.12rem; margin-bottom: .55rem; }
.kname .muted { font-family: var(--sans); font-weight: 400; }
.kgrid { display: grid; grid-template-columns: minmax(0, 1.35fr) minmax(0, 1fr) minmax(0, 1fr); gap: 1rem; margin-top: .8rem; }
.kcell { min-width: 0; padding: .7rem .8rem; background: var(--bg-sunken); border-radius: var(--radius-sm); }
.kcell small { display: block; color: var(--muted); font-size: .7rem; text-transform: uppercase; letter-spacing: .05em; margin-bottom: .3rem; font-weight: 600; }
.kcell .bound { font-size: 1.05rem; overflow-x: auto; overflow-y: hidden; padding-bottom: .1rem; }
.kcell .bound .katex { font-size: 1.1em; }
.kcell .cite { font-size: .8rem; }
.kcell .cite-after { font-size: .8rem; margin-left: .3rem; }
.kcell .chips { margin-top: .4rem; }
.lb + .lb { margin-top: .7rem; padding-top: .6rem; border-top: 1px dashed var(--line-strong); }
.lb-row { display: grid; grid-template-columns: 5.2rem minmax(0, 1fr); gap: .4rem; margin-top: .4rem; font-size: .84rem; align-items: baseline; }
.lb-row .lbl { color: var(--muted); font-size: .68rem; text-transform: uppercase; letter-spacing: .05em; font-weight: 600; padding-top: .15rem; }
.lb-row .bottleneck { font-weight: 500; }
ul.pre { list-style: none; margin: 0; padding: 0; display: flex; flex-direction: column; gap: .15rem; }
ul.pre li { position: relative; padding-left: .85rem; color: var(--fg); line-height: 1.4; }
ul.pre li::before { content: ""; position: absolute; left: 0; top: .55em; width: .35rem; height: .35rem; border-radius: 50%; background: var(--line-strong); }
ul.pre li p { margin: 0; display: inline; }

.meter { display: grid; grid-template-columns: auto minmax(5rem, 11rem) minmax(0, 1fr); align-items: center; gap: .7rem; }
.meter .bar { height: .5rem; border-radius: 999px; background: var(--unknown-soft); position: relative; overflow: hidden; }
.meter .bar::after { content: ""; position: absolute; inset: 0; border-radius: 999px; }
.meter.tight .bar::after { background: var(--tight); }
.meter.near .bar::after { background: linear-gradient(90deg, var(--tight) 0 70%, var(--near) 70% 100%); }
.meter.gap .bar::after { background: linear-gradient(90deg, var(--tight) 0 35%, var(--gap) 35% 100%); }
.meter.impossible .bar::after { background: var(--fg); opacity: .85; }
.meter.unknown .bar::after { background: repeating-linear-gradient(90deg, var(--unknown) 0 6px, transparent 6px 12px); opacity: .6; }
.gapnote { font-size: .86rem; color: var(--muted); }
.gapnote:empty { display: none; }

/* ---------- results ---------- */
.result { display: grid; grid-template-columns: minmax(0, 1fr) auto; gap: .35rem 1rem; padding: .75rem 0; border-top: 1px solid var(--line); }
.result:first-of-type { border-top: 0; padding-top: .1rem; }
.result .who { font-weight: 500; display: flex; flex-wrap: wrap; align-items: center; gap: .4rem; }
.result .bounds-inline { color: var(--muted); font-size: .9rem; display: flex; flex-wrap: wrap; gap: .3rem 1rem; justify-content: flex-end; }
.result .bounds-inline b { color: var(--fg); font-weight: 500; }
.result .note { grid-column: 1 / -1; font-size: .92rem; }
.result .note p { margin: .25rem 0 0; }
.result .note .chips { margin-bottom: .2rem; }

ol.open { padding-left: 1.3rem; margin: 0; }
ol.open li { margin: .45rem 0; }
ol.open li p { margin: 0; }

.cite { font-size: .9em; color: var(--accent); white-space: nowrap; }
.cite::before { content: "["; } .cite::after { content: "]"; }

.ref { padding: .65rem 0; border-bottom: 1px solid var(--line); scroll-margin-top: 5rem; }
.ref .key { font-family: var(--mono); font-size: .78rem; color: var(--muted); }
.ref .title { font-weight: 500; }
.ref .links a { margin-right: .8rem; font-size: .86rem; }
.ref:target { background: var(--accent-soft); }

.axes td:first-child { white-space: nowrap; font-weight: 500; }

/* ---------- overview essays ---------- */
.overviews { margin: .2rem 0 1.2rem; }
.essay { max-width: 76ch; margin: 0 auto; }
.essay header { margin-bottom: 1.2rem; }
.essay header h1 { font-size: 2.2rem; text-wrap: balance; }
.essay header .chips { margin: .6rem 0; }
.essay .toc { background: var(--bg-sunken); border-radius: var(--radius); padding: .9rem 1.2rem; margin: 1rem 0 1.6rem; }
.essay .toc ol { margin: 0; padding-left: 1.2rem; }
.essay .toc li { margin: .15rem 0; }
.essay section { scroll-margin-top: 4.5rem; }
.essay section h2 { font-size: 1.5rem; margin-top: 2.2rem; text-wrap: balance; }
.essay .prose { font-size: 1.04rem; line-height: 1.65; }
.essay .prose p { margin: .7rem 0 1rem; }
.essay .prose blockquote { margin: 1rem 0; padding: .4rem 1rem; border-left: 3px solid var(--line-strong); color: var(--muted); font-style: italic; }
.essay .prose blockquote p { margin: .3rem 0; }
.essay .prose h3 { font-size: 1.15rem; margin-top: 1.5rem; }
.essay .prose table { font-size: .92rem; margin: .8rem 0; }
.chip a, a.chip { text-decoration: none; }

/* ---------- map ---------- */
.map .row { display: grid; grid-template-columns: minmax(0, 1.4fr) 1fr 1fr; gap: .8rem; align-items: center; padding: .55rem .6rem; border-top: 1px solid var(--line); }
.map .row:hover { background: var(--accent-soft); }
.map .row .name a { font-weight: 500; }
.map .row .name .summary { font-size: .82rem; color: var(--muted); }
.map .head { font-size: .74rem; text-transform: uppercase; letter-spacing: .05em; color: var(--muted); border: 0; }
.map .mini { display: flex; flex-direction: column; gap: .15rem; font-size: .88rem; min-width: 0; }
.map .mini .vs { overflow-x: auto; }
.map .mini .katex { font-size: .95em; }
.legend { display: flex; flex-wrap: wrap; gap: .9rem; font-size: .84rem; color: var(--muted); margin: .4rem 0 1rem; align-items: center; }
.legend span { display: inline-flex; align-items: center; gap: .3rem; }

.empty { color: var(--muted); font-style: italic; }
.error { background: var(--gap-soft); color: var(--gap); padding: 1rem; border-radius: var(--radius); }

/* ---------- responsive ---------- */
@media (max-width: 1080px) {
  .kgrid { grid-template-columns: 1fr 1fr; }
  .kgrid .kcell:first-child { grid-column: 1 / -1; }
}
@media (max-width: 900px) {
  .layout { grid-template-columns: 1fr; }
  .sidebar { position: static; max-height: none; }
  .sidenav { background: var(--bg-elev); border: 1px solid var(--line); border-radius: var(--radius); padding: .6rem .9rem; }
  .sidenav > summary { cursor: pointer; }
  .sidehead { margin: 0; flex-wrap: wrap; }
  .sidehead .current { display: block; width: 100%; font-size: .9rem; color: var(--fg); margin-top: .2rem; }
  .sidehead .current::before { content: "▸ "; color: var(--muted); }
  .sidenav[open] .sidehead .current::before { content: "▾ "; }
  .sidenav[open] .sidehead { margin-bottom: .6rem; }
  .map .row { grid-template-columns: 1fr; }
  .map .head { display: none; }
  .hero h1 { font-size: 1.9rem; }
  .meter { grid-template-columns: auto minmax(0, 1fr); }
  .meter .gapnote { grid-column: 1 / -1; }
  .result { grid-template-columns: 1fr; }
  .result .bounds-inline { justify-content: flex-start; }
}
@media (max-width: 600px) {
  .topbar { flex-wrap: wrap; row-gap: .25rem; padding: .55rem 16px; }
  .brand { font-size: 1rem; white-space: nowrap; }
  .topbar nav { flex-wrap: wrap; gap: .35rem .9rem; font-size: .86rem; width: 100%; min-width: 0; justify-content: flex-start; }
  .topbar nav a { padding: .15rem 0; white-space: nowrap; }
  .kgrid { grid-template-columns: 1fr; }
  .lb-row { grid-template-columns: 1fr; gap: .15rem; }
}

/* ---------- assumption tree (computed; root = no assumptions) ---------- */
.dot.hollow { background: transparent; box-shadow: inset 0 0 0 1.5px var(--unknown); }
.badge.std { background: var(--accent-soft); color: var(--accent); }
.tree a.gapnode .t { color: var(--muted); font-style: italic; }
.tree a.gapnode.active .t { color: #fff; }
.tree a.gapnode .delta { font-style: normal; }
.chip .lvl { display: inline-block; min-width: 1.1em; margin-right: .35em; padding: 0 .3em; border-radius: 4px; background: rgba(127,127,127,.18); font-size: .72em; font-weight: 600; text-align: center; }

.bigtree, .bigtree ul { list-style: none; margin: 0; padding: 0; }
.bigtree ul { margin-left: 1.05rem; padding-left: 0; }
.bigtree li { position: relative; padding-left: 1.25rem; margin: .35rem 0 0; }
.bigtree > li { padding-left: 0; }
/* connectors: a vertical line from the parent down to the last child, an elbow into each child */
.bigtree ul > li::before { content: ""; position: absolute; left: 0; top: 0; bottom: 0; border-left: 1.5px solid var(--line-strong); }
.bigtree ul > li:last-child::before { bottom: auto; height: 1.15rem; }
.bigtree ul > li::after { content: ""; position: absolute; left: 0; top: 1.15rem; width: 1rem; border-top: 1.5px solid var(--line-strong); }
.bigtree .edge { margin: 0 0 .2rem; padding-top: .55rem; }
.bigtree .edge .chip { font-size: .72rem; padding: .1rem .45rem; }
.bigtree .node { display: grid; grid-template-columns: minmax(0, 1fr) auto; gap: .1rem .6rem; align-items: center; padding: .5rem .75rem; border: 1px solid var(--line); border-radius: var(--radius-sm); background: var(--bg-elev); color: var(--fg); max-width: 44rem; }
.bigtree .node:hover { border-color: var(--accent); text-decoration: none; }
.bigtree .nt { font-weight: 600; font-size: .93rem; }
.bigtree .ns { grid-column: 1 / -1; color: var(--muted); font-size: .82rem; line-height: 1.4; }
.bigtree li.gap > .node { background: transparent; border-style: dashed; }
.bigtree li.gap > .node .nt { color: var(--muted); font-weight: 500; font-style: italic; }
.bigtree li.standard > .node { border-color: var(--accent); box-shadow: 0 0 0 1px var(--accent) inset; }
.bigtree > li > .node { background: var(--bg-sunken); }

.crumbs.path { font-size: .8rem; line-height: 1.6; }
.card.gapcard { background: transparent; border-style: dashed; box-shadow: none; }
.card.gapcard h3 { color: var(--muted); font-style: italic; font-weight: 500; }
.map .row.gaprow .name a { color: var(--muted); font-style: italic; font-weight: 400; }

.imp-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 1.2rem; }
.imp-grid h4 { font-family: var(--sans); font-size: .82rem; font-weight: 600; margin: .2rem 0 .5rem; }
.imp { padding: .45rem 0; border-top: 1px solid var(--line); font-size: .88rem; }
.imp .bounds-inline { margin-top: .15rem; }

/* home: model › family › problem */
.model-h { margin-top: .2rem; }
.family { margin-top: 1.1rem; padding-top: .9rem; border-top: 1px solid var(--line); }
.family:first-of-type { border-top: 0; padding-top: 0; }
.fam-h { margin: 0 0 .2rem; font-size: 1.15rem; }
.fam-h .eyebrow { display: block; margin-bottom: .1rem; }

@media (max-width: 900px) {
  .imp-grid { grid-template-columns: 1fr; }
  .bigtree ul { margin-left: .35rem; }
  .bigtree li { padding-left: .9rem; }
  .bigtree ul > li::after { width: .7rem; }
}
.bigtree li.gap > .node { padding: .25rem .65rem; max-width: 26rem; }
.bigtree li.gap > .node .nt { font-size: .84rem; }
.bigtree .split { font-style: normal; font-weight: 400; font-size: .78rem; }
.bigtree li.gap > .node .dots { display: none; }
@media (min-width: 901px) { .layout { grid-template-columns: 320px minmax(0, 1fr); } }
.tree ul { margin-left: .45rem; padding-left: .3rem; }
.imp .bounds-inline { display: flex; flex-wrap: wrap; gap: .2rem 1rem; }

/* ---------- view switch and assumption graph ---------- */
.viewhead { margin-top: 1.4rem; }
.viewhead h2 { margin: 0; }
.viewswitch { display: inline-flex; border: 1px solid var(--line-strong); border-radius: 999px; overflow: hidden; flex: none; }
.viewswitch a { padding: .25rem .8rem; font-size: .82rem; color: var(--muted); }
.viewswitch a + a { border-left: 1px solid var(--line-strong); }
.viewswitch a.on { background: var(--accent); color: #fff; }
.viewswitch a:hover { text-decoration: none; color: var(--fg); }
.viewswitch a.on:hover { color: #fff; }

.gwrap { overflow: auto; margin: .6rem -.4rem 0; padding: .4rem; border: 1px solid var(--line); border-radius: var(--radius-sm); background: var(--bg-sunken); max-height: 78vh; }
.gcanvas { position: relative; }
.gsvg { position: absolute; left: 0; top: 0; overflow: visible; }
.gedge { fill: none; stroke: var(--line-strong); stroke-width: 1.4; marker-end: url(#garrow); transition: opacity .12s; }
.garrowhead { fill: var(--line-strong); }
.glabel { position: absolute; transform: translate(-50%, -50%); font-size: .68rem; line-height: 1.2; padding: .05rem .4rem; border-radius: 999px; background: var(--stronger-soft); color: var(--stronger); white-space: nowrap; max-width: 150px; overflow: hidden; text-overflow: ellipsis; pointer-events: auto; transition: opacity .12s; }
.glabel .katex { font-size: .95em; }
.gnode { position: absolute; display: flex; flex-direction: column; justify-content: center; gap: .2rem; padding: .35rem .55rem; border: 1px solid var(--line); border-radius: var(--radius-sm); background: var(--bg-elev); color: var(--fg); box-shadow: var(--shadow); font-size: .8rem; line-height: 1.25; overflow: hidden; transition: opacity .12s, border-color .12s; }
.gnode:hover, .gnode:focus { text-decoration: none; border-color: var(--accent); }
.gnode .gt { font-weight: 600; display: -webkit-box; -webkit-line-clamp: 2; -webkit-box-orient: vertical; overflow: hidden; }
.gnode .dots { align-self: flex-start; }
.gnode.groot { border-style: dashed; background: transparent; box-shadow: none; }
.gnode.groot .gt { font-style: italic; font-weight: 500; color: var(--muted); }
.gnode.standard { border-color: var(--accent); box-shadow: 0 0 0 1px var(--accent) inset; }
.gcanvas.focus .gnode, .gcanvas.focus .gedge, .gcanvas.focus .glabel { opacity: .22; }
.gcanvas.focus .gnode.on, .gcanvas.focus .gnode.up, .gcanvas.focus .gnode.down,
.gcanvas.focus .gedge.up, .gcanvas.focus .gedge.down, .gcanvas.focus .glabel.up, .gcanvas.focus .glabel.down { opacity: 1; }
.gcanvas.focus .gnode.on { border-color: var(--accent); }
.gcanvas.focus .gnode.up { border-color: var(--weaker); }
.gcanvas.focus .gnode.down { border-color: var(--stronger); }
.gcanvas.focus .gedge.up { stroke: var(--weaker); stroke-width: 2; }
.gcanvas.focus .gedge.down { stroke: var(--stronger); stroke-width: 2; }
.gsizer { position: relative; }
.gcanvas { position: absolute; left: 0; top: 0; }
.glabel { max-width: 132px; }
.glabel.many { display: none; }
.gcanvas.focus .glabel.many.up, .gcanvas.focus .glabel.many.down { display: block; }
.gtools { display: flex; gap: .3rem; justify-content: flex-end; align-items: center; margin-top: .4rem; }
.gtools button { font: inherit; font-size: .8rem; padding: .15rem .6rem; border: 1px solid var(--line-strong); border-radius: 6px; background: var(--bg-elev); color: var(--fg); cursor: pointer; }
.gtools button:hover { border-color: var(--accent); }
/* the graph gets the full window width on large screens */
@media (min-width: 1100px) {
  .gpanel { width: calc(100vw - 48px); margin-left: calc(50% - 50vw + 24px); }
}

/* problem families as trees of problems: derived problems hang under their parent */
/* a grid of problems; a problem with derived problems takes a full row and its
   derived problems fill a grid beneath it, so wide screens are used */
.ftree { display: grid; grid-template-columns: repeat(auto-fill, minmax(min(100%, 270px), 1fr)); gap: .9rem; margin: .8rem 0; align-items: start; }
.fnode { min-width: 0; }
.fnode.has-kids { grid-column: 1 / -1; }
.fnode > .card { margin: 0; }
.fnode.has-kids > .card { max-width: 46rem; }
.fkids { margin-left: 1.1rem; padding-left: .9rem; border-left: 2px solid var(--line-strong); }
.fgrid { display: grid; grid-template-columns: repeat(auto-fill, minmax(min(100%, 250px), 1fr)); grid-auto-flow: row dense; gap: 0 .9rem; align-items: start; }
.fgrid > .fderived.deep { grid-column: span 2; }
@media (max-width: 640px) { .fgrid > .fderived.deep { grid-column: auto; } }
.fderived { padding-top: .6rem; min-width: 0; }
.fderived > .eyebrow { display: block; margin: 0 0 .3rem; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.fderived > .eyebrow.rep { visibility: hidden; }
.fkids:not(.many) .fgrid { grid-template-columns: minmax(0, 1fr); }
@media (max-width: 640px) { .fderived > .eyebrow.rep { display: none; } }
.panel.relation .prose p { margin: .2rem 0 .6rem; }

/* papers as leaves of the assumption graph */
.gnode.gpaper { flex-direction: row; align-items: center; padding: .15rem .55rem; font-size: .74rem; border-radius: 999px; background: var(--bg); box-shadow: none; border-color: var(--line-strong); }
.gnode.gpaper .gt { font-weight: 500; -webkit-line-clamp: 1; }
.gnode.gpaper.own { border-color: var(--near); }
.gedge.gpe { stroke-width: 1.1; marker-end: none; stroke-dasharray: 4 3; opacity: .75; }
.gedge.gpe.best { stroke: var(--tight); }
.gedge.gpe.introductory { stroke: var(--accent); }
.gedge.gpe.lb { stroke: var(--gap); }
.gedge.gpe.other { stroke: var(--line-strong); }
.pline { display: inline-block; width: 22px; border-top: 2px dashed var(--line-strong); vertical-align: middle; }
.pline.best { border-color: var(--tight); } .pline.introductory { border-color: var(--accent); } .pline.lb { border-color: var(--gap); }
.gtools .gsep { flex: 1; }
.gcanvas.focus .gedge.gpe.up, .gcanvas.focus .gedge.gpe.down { stroke-width: 1.8; stroke-dasharray: none; }
.gcanvas.focus .gedge.gpe.up.best, .gcanvas.focus .gedge.gpe.down.best { stroke: var(--tight); }
.frel { font-size: .8rem; color: var(--muted); margin: .35rem .2rem 0; }
.frel::before { content: "↔ "; }

/* chronological view */
.timeline { padding-left: 1.2rem; }
.tl-decade { font-family: var(--serif); font-size: 1.3rem; font-weight: 600; margin: 1.2rem 0 .4rem -1rem; color: var(--muted); }
.tl-year { display: grid; grid-template-columns: 3.6rem minmax(0, 1fr); gap: .8rem; padding: .55rem 0; border-left: 2px solid var(--line-strong); margin-left: .2rem; }
.tl-y { font-weight: 600; font-variant-numeric: tabular-nums; position: relative; padding-left: .8rem; }
.tl-y::before { content: ""; position: absolute; left: -.42rem; top: .45rem; width: .7rem; height: .7rem; border-radius: 50%; background: var(--bg-elev); border: 2px solid var(--accent); }
.tl-origin { background: var(--accent-soft); border-radius: var(--radius-sm); padding: .55rem .8rem; margin-bottom: .5rem; }
.tl-origin .eyebrow { display: block; margin: 0 0 .15rem; }
.tl-pname { font-family: var(--serif); font-weight: 600; font-size: 1.05rem; }
.tl-papers { margin: 0; padding-left: 1rem; font-size: .86rem; }
.tl-papers li { margin: .15rem 0; }
.tl-role { font-size: .72rem; padding: .02rem .4rem; border-radius: 999px; background: var(--unknown-soft); color: var(--muted); white-space: nowrap; }
.tl-role.best { background: var(--tight-soft); color: var(--tight); }
.tl-role.introductory { background: var(--accent-soft); color: var(--accent); }
.tl-role.lb { background: var(--gap-soft); color: var(--gap); }
.focus { border-left: 3px solid var(--accent); padding: .45rem .8rem; margin: .5rem 0 .8rem; background: var(--accent-soft); border-radius: 0 var(--radius-sm) var(--radius-sm) 0; font-size: .92rem; }
.focus .eyebrow { display: block; margin: 0 0 .2rem; }
.panel.history .prose p:first-child { margin-top: 0; }
.axis-list { padding-top: .4rem; padding-bottom: .4rem; }
.axis-block { padding: .9rem 0; border-top: 1px solid var(--line); }
.axis-block:first-child { border-top: 0; }
.axis-head { display: flex; flex-wrap: wrap; align-items: baseline; gap: .4rem 1rem; }
.axis-head h3 { margin: 0; font-size: 1.02rem; }
.axis-origin { margin-top: .5rem; }
.axis-origin p { margin: 0; }
.panel.story h3 { margin-top: 0; }
details.defs { margin-top: .5rem; font-size: .86rem; }
details.defs summary { cursor: pointer; color: var(--accent); font-size: .8rem; }
details.defs dl { margin: .4rem 0 0; display: grid; grid-template-columns: minmax(9rem, max-content) minmax(0, 1fr); gap: .3rem .9rem; }
details.defs dt { font-weight: 600; }
details.defs dd { margin: 0; color: var(--fg); }
details.defs .lvl { display: inline-block; min-width: 1.1em; margin-right: .35em; padding: 0 .3em; border-radius: 4px; background: rgba(127,127,127,.18); font-size: .72em; text-align: center; }
@media (max-width: 600px) { details.defs dl { grid-template-columns: 1fr; } details.defs dd { margin-bottom: .4rem; } }

/* results whose proofs are disputed in the literature */
:root { --disputed: #8a3ffc; --disputed-soft: #f0e8ff; }
@media (prefers-color-scheme: dark) { :root:not([data-theme="light"]) { --disputed: #c4a0ff; --disputed-soft: #2c2240; } }
:root[data-theme="dark"] { --disputed: #c4a0ff; --disputed-soft: #2c2240; }
.badge.disputed { background: var(--disputed-soft); color: var(--disputed); }
.gedge.gpe.disputed { stroke: var(--disputed); }
.pline.disputed { border-color: var(--disputed); }
.result:has(.badge.disputed) { border-left: 3px solid var(--disputed); padding-left: .6rem; }

/* citing the atlas */
.cite-link .q, .cite-footer .q, h1 .q { font-family: var(--serif); font-size: 1.15em; line-height: 0; vertical-align: -0.12em; color: var(--accent); }
.cite-footer { max-width: 920px; margin: 0 auto .6rem; padding: .6rem .9rem; border-left: 3px solid var(--accent); background: var(--bg-elev); border-radius: 0 var(--radius-sm) var(--radius-sm) 0; text-align: left; font-size: .85rem; line-height: 1.45; }
.cite-footer .lbl { font-weight: 600; color: var(--fg); margin-right: .3rem; }
.cite-footer .txt { color: var(--fg); }
.citebox .citetext { font-size: 1.02rem; }
.citebox pre.bibtex { background: var(--bg-sunken); padding: .7rem .9rem; border-radius: var(--radius-sm); overflow-x: auto; font-size: .85rem; }
.citebox button { font: inherit; font-size: .85rem; padding: .3rem .9rem; border-radius: 8px; border: 1px solid var(--accent); background: var(--accent); color: #fff; cursor: pointer; }

/* cite popup */
dialog.cite-modal { border: none; padding: 0; background: transparent; max-width: min(640px, calc(100vw - 32px)); width: 100%; }
dialog.cite-modal::backdrop { background: rgba(20, 18, 12, .45); }
.cite-modal-card { position: relative; background: var(--bg-elev); color: var(--fg); border-radius: var(--radius); box-shadow: 0 10px 40px rgba(0,0,0,.25); padding: 1.3rem 1.4rem 1.2rem; border-top: 3px solid var(--accent); }
.cite-modal-card h2 { margin: 0 0 .8rem; font-size: 1.3rem; }
.cite-modal-card pre.bibtex { background: var(--bg-sunken); padding: .7rem .9rem; border-radius: var(--radius-sm); overflow-x: auto; font-size: .82rem; margin: .3rem 0 .8rem; }
.cite-modal-card .citetext { margin: .2rem 0 .9rem; }
.cite-actions { display: flex; gap: 1rem; align-items: center; flex-wrap: wrap; }
.cite-actions button { font: inherit; font-size: .85rem; padding: .3rem .9rem; border-radius: 8px; border: 1px solid var(--accent); background: var(--accent); color: #fff; cursor: pointer; }
.cite-close { position: absolute; top: .5rem; right: .7rem; border: none; background: transparent; font-size: 1.5rem; line-height: 1; color: var(--muted); cursor: pointer; }
.cite-close:hover { color: var(--fg); }

/* AI-use disclaimer */
.ai-note { font-size: .86rem; color: var(--muted); margin: .2rem 0 .6rem; }
.ai-note .ai-tag { display: inline-block; font-size: .7rem; font-weight: 600; letter-spacing: .04em; text-transform: uppercase; padding: .05rem .45rem; border-radius: 999px; background: var(--accent-soft); color: var(--accent); margin-right: .3rem; vertical-align: .08em; }
.ai-note.foot { max-width: 920px; margin: 0 auto .5rem; text-align: center; }

/* bottom navigation of overview essays */
.essay-nav { max-width: 76ch; margin: 2rem auto 1rem; padding-top: 1rem; border-top: 1px solid var(--line-strong); }
.essay-nav-row { display: grid; grid-template-columns: 1fr auto 1fr; gap: .8rem; align-items: center; }
.essay-nav-link { display: flex; flex-direction: column; gap: .15rem; padding: .55rem .75rem; border: 1px solid var(--line); border-radius: 10px; background: var(--bg-elev); text-decoration: none; min-width: 0; }
.essay-nav-link:hover { border-color: var(--accent); }
.essay-nav-link.next { text-align: right; }
.essay-nav-mid { display: flex; flex-direction: column; align-items: center; gap: .2rem; font-size: .88rem; }
.essay-nav-probs { margin-top: .8rem; display: flex; flex-wrap: wrap; gap: .35rem; align-items: center; }
@media (max-width: 640px) {
  .essay-nav-row { grid-template-columns: 1fr 1fr; }
  .essay-nav-mid { grid-column: 1 / -1; grid-row: 2; flex-direction: row; justify-content: center; gap: .9rem; }
}
.to-top { position: fixed; right: 1.2rem; bottom: 1.4rem; width: 2.6rem; height: 2.6rem; display: flex; align-items: center; justify-content: center; border-radius: 50%; background: var(--bg-elev); border: 1px solid var(--line-strong); color: var(--accent); font-size: 1.2rem; text-decoration: none; box-shadow: 0 2px 8px rgba(0,0,0,.12); z-index: 20; }
.to-top:hover { border-color: var(--accent); background: var(--accent); color: #fff; }
@media print { .to-top, .essay-nav { display: none; } }

/* ---------- home page ---------- */
:root { --m0: #3553c9; --m1: #0f7b6c; --m2: #b5502b; --m3: #7a3fb0; }
@media (prefers-color-scheme: dark) { :root:not([data-theme="light"]) { --m0: #93a7ff; --m1: #5fd0bd; --m2: #f0a07e; --m3: #c79bf2; } }
:root[data-theme="dark"] { --m0: #93a7ff; --m1: #5fd0bd; --m2: #f0a07e; --m3: #c79bf2; }
.home-hero { display: grid; grid-template-columns: minmax(0, 1.5fr) minmax(0, 1fr); gap: 2rem; align-items: center; padding: 1.4rem 0 1.6rem; border-bottom: 1px solid var(--line); margin-bottom: 1.4rem; }
.home-hero h1 { font-size: clamp(2.2rem, 4vw, 3.2rem); line-height: 1.05; margin: 0 0 .5rem; letter-spacing: -.01em; }
.home-hero .tagline { font-size: 1.15rem; color: var(--muted); max-width: 46ch; margin: 0 0 .6rem; }
.hh-intro { max-width: 62ch; margin: .8rem 0 1rem; line-height: 1.6; }
.hh-links { display: flex; flex-wrap: wrap; gap: .5rem; }
.btn { display: inline-block; padding: .45rem .95rem; border-radius: 999px; background: var(--accent); color: #fff; border: 1px solid var(--accent); font-size: .9rem; text-decoration: none; }
.btn:hover { text-decoration: none; filter: brightness(1.08); }
.btn.ghost { background: transparent; color: var(--accent); }
.hh-glance { padding: 1.1rem 1.2rem; margin: 0; }
.glance-nums { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: .5rem; margin: .4rem 0 1rem; }
.glance-nums div { display: flex; flex-direction: column; }
.glance-nums b { font-family: var(--serif); font-size: 1.7rem; line-height: 1.1; }
.glance-nums span { font-size: .76rem; color: var(--muted); }
.sbar { display: flex; height: 10px; border-radius: 999px; overflow: hidden; background: var(--bg-sunken); gap: 2px; margin: .4rem 0; }
.sbar span { display: block; min-width: 3px; }
.sb-tight { background: var(--tight); } .sb-near { background: var(--near); } .sb-gap { background: var(--gap); } .sb-unknown { background: var(--line-strong); } .sb-impossible { background: var(--fg); }
.sbar-legend { display: flex; flex-wrap: wrap; gap: .3rem .9rem; font-size: .8rem; color: var(--muted); margin: .4rem 0 .5rem; }
.sbar-legend i { display: inline-block; width: .65rem; height: .65rem; border-radius: 2px; margin-right: .3rem; vertical-align: -1px; }
.sbar-legend b { color: var(--fg); font-weight: 600; margin-right: .15rem; }
.mgrid { display: grid; grid-template-columns: repeat(auto-fill, minmax(min(100%, 460px), 1fr)); gap: 1rem; margin: .6rem 0 2rem; }
.mcard { background: var(--bg-elev); border: 1px solid var(--line); border-top: 4px solid var(--mc, var(--accent)); border-radius: var(--radius); padding: 1.1rem 1.2rem 1rem; display: flex; flex-direction: column; gap: .55rem; min-width: 0; }
.mcard.m0 { --mc: var(--m0); } .mcard.m1 { --mc: var(--m1); } .mcard.m2 { --mc: var(--m2); } .mcard.m3 { --mc: var(--m3); }
.mcard header .eyebrow { color: var(--mc); }
.mcard h3 { font-size: 1.35rem; margin: .1rem 0 .3rem; }
.mcard h3 a { color: var(--fg); }
.mcard header p { margin: 0; font-size: .92rem; }
.mstats { display: flex; flex-wrap: wrap; gap: .3rem 1rem; font-size: .82rem; color: var(--muted); }
.mstats b { color: var(--fg); font-family: var(--serif); font-size: 1.05rem; margin-right: .15rem; }
.mfams { display: flex; flex-direction: column; gap: .7rem; margin-top: .3rem; }
.mfam h4 { margin: 0 0 .3rem; font-size: .74rem; text-transform: uppercase; letter-spacing: .06em; color: var(--muted); font-weight: 600; }
.plinks { display: flex; flex-wrap: wrap; gap: .3rem; }
.plink { display: inline-block; padding: .2rem .6rem; border-radius: 999px; border: 1px solid var(--line-strong); font-size: .84rem; color: var(--fg); background: var(--bg); text-decoration: none; }
.plink:hover { border-color: var(--mc, var(--accent)); color: var(--mc, var(--accent)); text-decoration: none; }
.plink.derived { border-style: dashed; color: var(--muted); }
.plink.derived::before { content: "↳ "; opacity: .6; }
.mmore { margin-top: auto; padding-top: .5rem; font-size: .85rem; color: var(--mc); }
.ovgrid { display: grid; grid-template-columns: repeat(auto-fill, minmax(min(100%, 300px), 1fr)); gap: .2rem 1.6rem; margin: .4rem 0 2rem; }
.ovitem { display: block; padding: .75rem 0; border-top: 1px solid var(--line); color: var(--fg); text-decoration: none; }
.ovitem:hover { text-decoration: none; }
.ovitem:hover h4 { color: var(--accent); }
.ovitem h4 { font-family: var(--serif); font-size: 1.05rem; margin: 0 0 .25rem; }
.ovitem p { margin: 0; font-size: .86rem; color: var(--muted); display: -webkit-box; -webkit-line-clamp: 3; -webkit-box-orient: vertical; overflow: hidden; }
@media (max-width: 860px) {
  .home-hero { grid-template-columns: minmax(0, 1fr); gap: 1.2rem; }
  .glance-nums { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

/* ---------- model landscape ---------- */
.landscape h3 { margin-top: 1.4rem; }
.land-tabs { display: flex; flex-wrap: wrap; gap: .4rem; margin: .8rem 0 .3rem; }
.land-tabs button, .land-tabs a { font: inherit; font-size: .85rem; padding: .3rem .9rem; border-radius: 999px; border: 1px solid var(--line-strong); background: var(--bg-elev); color: var(--fg); cursor: pointer; }
.land-tabs button.on, .land-tabs a.on { background: var(--accent); border-color: var(--accent); color: #fff; }
.land-scroll { overflow-x: auto; -webkit-overflow-scrolling: touch; }
.landgrid { border-collapse: separate; border-spacing: 6px; margin: .4rem 0; }
.landgrid th { font-size: .78rem; font-weight: 600; color: var(--muted); text-align: center; padding: 0 .2rem; white-space: nowrap; }
.landgrid tbody th { text-align: left; padding-right: .6rem; }
.landgrid tbody th b { display: block; color: var(--fg); font-size: .9rem; }
.landgrid tbody th span { font-weight: 400; font-size: .74rem; }
.lcell { width: 4.2rem; height: 2.6rem; border-radius: 8px; border: 1.5px solid var(--line-strong); background: var(--bg-elev); color: var(--fg); cursor: pointer; font: inherit; font-size: 1.05rem; font-weight: 600; }
.lcell:hover { border-color: var(--accent); }
.lcell.st-self { background: var(--accent); border-color: var(--accent); color: #fff; }
.lcell.st-strong, .land-legend i.st-strong { background: var(--tight-soft, #e3f2e9); border-color: var(--tight); color: var(--tight); }
.lcell.st-weak, .land-legend i.st-weak { background: var(--near-soft, #f8eedd); border-color: var(--near); color: var(--near); }
.lcell.st-eq, .land-legend i.st-eq { background: var(--accent-soft); border-color: var(--accent); color: var(--accent); }
.lcell.st-inc, .land-legend i.st-inc { background: var(--disputed-soft); border-color: var(--disputed); color: var(--disputed); }
.lcell.st-unk, .land-legend i.st-unk { background: var(--bg-sunken); border-color: var(--line); color: var(--muted); }
.lcell.derived, .land-legend i.derived { border-style: dashed; }
.land-legend { display: flex; flex-wrap: wrap; gap: .3rem 1rem; align-items: center; font-size: .82rem; color: var(--muted); margin: .5rem 0 .2rem; }
.land-legend i { display: inline-block; width: .9rem; height: .9rem; border-radius: 3px; border: 1.5px solid; margin-right: .3rem; vertical-align: -2px; }
.lm sup { font-size: .68em; margin-left: .05em; }
.landrel { width: 100%; border-collapse: collapse; font-size: .86rem; }
.landrel th, .landrel td { text-align: left; padding: .4rem .5rem; border-bottom: 1px solid var(--line); vertical-align: top; }
.landrel th { font-size: .74rem; text-transform: uppercase; letter-spacing: .05em; color: var(--muted); font-weight: 600; }
.landrel .lrel { font-weight: 700; text-align: center; }
.caveat { font-size: .8rem; color: var(--near); margin-top: .2rem; }
dl.seps dt { margin-top: .5rem; }
dl.seps dd { margin: .1rem 0 0 1rem; font-size: .88rem; }
ul.conflicts li { margin-bottom: .35rem; }
.home-hero .subtitle { font-family: var(--serif); font-size: clamp(1.15rem, 2vw, 1.45rem); line-height: 1.3; margin: 0 0 .6rem; max-width: 40ch; color: var(--accent); }

/* problem figures */
.pfig { float: right; width: min(46%, 420px); margin: 0 0 .8rem 1.2rem; background: var(--bg); border: 1px solid var(--line); border-radius: var(--radius-sm); padding: .5rem .6rem .4rem; }
.pfig .figsvg { width: 100%; height: auto; display: block; }
.pfig figcaption { font-size: .8rem; color: var(--muted); margin-top: .3rem; line-height: 1.4; }
.statement-body::after { content: ""; display: block; clear: both; }
@media (max-width: 720px) { .pfig { float: none; width: 100%; margin: 0 0 .8rem; } }
.figwrap { display: flex; flex-direction: column; }
.figplay { align-self: flex-end; margin-top: .35rem; width: 1.7rem; height: 1.7rem; border-radius: 50%; border: 1px solid var(--line-strong); background: var(--bg-elev); color: var(--muted); font: 600 .62rem/1 var(--sans); cursor: pointer; opacity: .75; transition: opacity .15s; }
.figplay:hover, .figplay:focus-visible { opacity: 1; color: var(--fg); }
/* open questions page */
ol.prio { padding-left: 1.4rem; }
ol.prio > li { margin: 0 0 1.3rem; padding-left: .3rem; }
ol.prio > li::marker { font-family: var(--serif); font-weight: 700; color: var(--accent); }
ol.prio h3 { margin: 0 0 .3rem; }
.otable td b { font-family: var(--serif); font-size: 1.05rem; }

/* search box in the top bar */
.search { position: relative; flex: 1 1 18rem; max-width: 30rem; }
.search input { width: 100%; box-sizing: border-box; font: inherit; font-size: .88rem; padding: .42rem .75rem; border: 1px solid var(--line); border-radius: 999px; background: var(--bg); color: var(--fg); }
.search input:focus { outline: none; border-color: var(--accent); box-shadow: 0 0 0 3px color-mix(in srgb, var(--accent) 18%, transparent); }
.search-results { position: absolute; left: 0; right: 0; top: calc(100% + 6px); background: var(--bg-elev); border: 1px solid var(--line); border-radius: var(--radius); box-shadow: var(--shadow); max-height: 70vh; overflow-y: auto; z-index: 30; padding: .3rem; }
.sr-item, .sr-all { display: grid; grid-template-columns: 6.5rem minmax(0, 1fr); gap: 0 .6rem; padding: .45rem .55rem; border-radius: 8px; color: var(--fg); text-decoration: none; }
.sr-item:hover, .sr-item.on, .sr-all:hover, .sr-all.on { background: var(--bg-sunken); text-decoration: none; }
.sr-type { grid-row: span 2; font-size: .7rem; text-transform: uppercase; letter-spacing: .04em; color: var(--muted); padding-top: .15rem; }
.sr-title { font-weight: 600; font-size: .9rem; overflow: hidden; text-overflow: ellipsis; }
.sr-sub { font-size: .78rem; color: var(--muted); overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.sr-all { display: block; font-size: .82rem; color: var(--accent); border-top: 1px solid var(--line); border-radius: 0 0 8px 8px; margin-top: .2rem; }
.sr-empty { padding: .6rem; color: var(--muted); font-size: .86rem; }
.search-page { display: flex; gap: .5rem; margin: .4rem 0 1rem; max-width: 40rem; }
.search-page input { flex: 1; font: inherit; padding: .5rem .8rem; border: 1px solid var(--line); border-radius: 8px; background: var(--bg-elev); color: var(--fg); min-width: 0; }
.search-page button { font: inherit; padding: .5rem 1rem; border-radius: 8px; border: 1px solid var(--accent); background: var(--accent); color: #fff; cursor: pointer; }
.search-list { padding: .3rem; }
.search-hit { display: flex; flex-direction: column; gap: .1rem; padding: .6rem .7rem; border-radius: 8px; color: var(--fg); }
.search-hit + .search-hit { border-top: 1px solid var(--line); }
.search-hit:hover { background: var(--bg-sunken); text-decoration: none; }
.sh-title { font-weight: 600; color: var(--accent); }
.search-hit mark { background: color-mix(in srgb, var(--near) 35%, transparent); color: inherit; border-radius: 2px; }
@media (max-width: 960px) { .topbar { flex-wrap: wrap; row-gap: .4rem; } .search { order: 3; flex-basis: 100%; max-width: none; } }
@media (max-width: 700px) { .search { order: 3; flex-basis: 100%; max-width: none; } .sr-item { grid-template-columns: 1fr; } .sr-type { grid-row: auto; } }

/* explore by assumptions */
.chip.on { background: var(--accent); color: #fff; border-color: var(--accent); }
.chip.on .lvl { background: rgba(255,255,255,.25); }
a.chip { text-decoration: none; cursor: pointer; }
a.chip:hover { border-color: var(--accent); }
.ex-models { margin-bottom: 1rem; flex-wrap: wrap; }
.ex-models a, .ex-panel .land-tabs a { text-decoration: none; }
.ex-axis { display: grid; grid-template-columns: 11rem minmax(0, 1fr); gap: .3rem 1rem; align-items: baseline; padding: .45rem 0; border-top: 1px solid var(--line); }
.ex-name { font-weight: 600; font-size: .88rem; }
.ex-table td { vertical-align: top; }
.ex-m { white-space: nowrap; display: flex; align-items: center; gap: .35rem; }
.ex-prob h3 { margin: 0; }
.ex-exact { margin: .4rem 0 .6rem; }
.ex-exact .dot, .ex-prob .bounds-inline .dot { margin-right: .3rem; }
@media (max-width: 600px) { .ex-axis { grid-template-columns: 1fr; } .ex-m { white-space: normal; flex-wrap: wrap; } }
.ex-exact .bounds-inline, .ex-prob .imp .bounds-inline { display: flex; flex-wrap: wrap; gap: .3rem 1.1rem; }

/* notation and the index of assumptions */
.nottable td.sym { white-space: nowrap; }
.nottable td { vertical-align: top; }
.ix-model h3 { margin-top: 0; }
.ix-axis { padding: .7rem 0; border-top: 1px solid var(--line); }
.ix-axis h4 { margin: 0 0 .3rem; font-size: .98rem; }
.ix-vals { margin: 0; display: grid; grid-template-columns: minmax(10rem, max-content) minmax(0, 1fr); gap: .35rem 1rem; font-size: .88rem; }
.ix-vals dt { font-weight: 600; }
.ix-vals dd { margin: 0; }
.ix-vals .lvl { display: inline-block; min-width: 1.1em; margin-right: .35em; padding: 0 .3em; border-radius: 4px; background: rgba(127,127,127,.18); font-size: .72em; text-align: center; }
@media (max-width: 600px) { .ix-vals { grid-template-columns: 1fr; } .ix-vals dd { margin-bottom: .4rem; } }

/* a first look: primer for newcomers */
details.primer > summary { cursor: pointer; display: flex; flex-wrap: wrap; align-items: baseline; gap: .3rem .8rem; list-style: none; }
details.primer > summary::-webkit-details-marker { display: none; }
details.primer > summary h3 { margin: 0; }
.idea { border-top: 1px solid var(--line); padding: .8rem 0 .4rem; }
.idea-head { display: flex; flex-wrap: wrap; align-items: center; gap: .35rem .6rem; margin-bottom: .3rem; }
.idea-n { display: inline-grid; place-items: center; width: 1.5rem; height: 1.5rem; border-radius: 50%; background: var(--accent); color: #fff; font-size: .8rem; font-weight: 600; }
.idea-analysis { background: var(--bg-sunken); border-radius: 8px; padding: .55rem .8rem; margin: .4rem 0; font-size: .92rem; }

/* explore on phones: results as cards */
.ex-jump { display: none; }
@media (max-width: 700px) {
  .ex-jump { display: inline; }
  .ex-table, .ex-table tbody, .ex-table tr, .ex-table td { display: block; width: 100%; }
  .ex-table thead { display: none; }
  .ex-table tr { border: 1px solid var(--line); border-radius: var(--radius); padding: .6rem .8rem; margin-bottom: .7rem; background: var(--bg-elev); }
  .ex-table td { border: 0; padding: .2rem 0; }
  .ex-table td::before { content: attr(data-label); display: block; font-size: .7rem; text-transform: uppercase; letter-spacing: .04em; color: var(--muted); }
  .ex-table td:first-child { font-weight: 600; font-size: 1rem; }
  .ex-table td:first-child::before { display: none; }
  .ex-m { white-space: normal; flex-wrap: wrap; }
  .ex-panel .chips { gap: .3rem; }
  .imp-grid { grid-template-columns: 1fr !important; }
}

/* contributing and acknowledgements */
.contribute { margin: 1.4rem 0 .4rem; padding-top: .8rem; border-top: 1px dashed var(--line); }
.foot-links { margin-top: .35rem; }
.ack-list { margin: 0; padding-left: 1.1rem; }
.ack-list li { margin: .3rem 0; }
:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; border-radius: 3px; }

/* ======================================================================
   Editorial layer: the atlas reads like a typeset survey. Serif text at a
   comfortable measure, sans-serif for interface labels, sections separated
   by rules and whitespace instead of boxes inside boxes.
   ====================================================================== */
body { font-family: var(--serif); font-size: 16.5px; line-height: 1.6; font-feature-settings: "kern", "liga", "onum" 0; }
.topbar, .eyebrow, .chip, .badge, .pill, .crumbs, .sidebar, .btn, .legend, th, .kcell small, .lb-row .lbl,
.map .head, .gnode, .glabel, .viewswitch, .land-tabs, .lcell, .landgrid th, .search, .search-results, .search-page,
.mstats, .plink, .glance-nums span, .sbar-legend, .footer, .gtools, .ex-name, button, input, select,
.idea-n, .tl-role, .tl-y, .hint, .ai-note, .cite-actions, .to-top, .dots, .sr-type, .ex-m, .essay-nav-mid, .frel,
.ref .links, .cite-modal-card pre, .glance-nums b + span { font-family: var(--sans); }
.small, .muted.small, .small.muted { font-size: .88rem; }
h1 { font-size: 2.35rem; font-weight: 600; letter-spacing: -.012em; text-wrap: balance; }
h2 { font-size: 1.5rem; text-wrap: balance; }
h3 { font-size: 1.15rem; }

/* the measure: running text stays near 72 characters a line */
.prose, .lead, .hh-intro, .statement-body > p, .statement-body > ul, .statement-body > ol, .statement-body > blockquote,
ol.open, .result .note, .panel > p, .panel > ul, .panel > ol, .idea > .prose, .idea > p, .ovitem p, .axis-origin, .essay,
ol.prio > li > p, ol.prio > li > .prose { max-width: var(--measure); }
.lead { font-size: 1.1rem; line-height: 1.55; }
p.muted.lead, .muted.lead { color: var(--muted); }
.prose li { margin: .2rem 0; }
.prose blockquote { margin: .8rem 0; padding: .1rem 0 .1rem 1rem; border-left: 2px solid var(--line-strong); color: var(--muted); }

/* chrome */
.topbar { background: var(--bg); backdrop-filter: none; padding: .7rem 24px; border-bottom: 1px solid var(--line); }
.brand { font-size: 1.2rem; letter-spacing: -.005em; }
.brand:hover { text-decoration: none; }
.topbar nav { gap: .3rem 1.25rem; font-size: .86rem; }
.topbar nav a { color: var(--muted); padding: .1rem 0; border-bottom: 1px solid transparent; }
.topbar nav a:hover { color: var(--fg); border-bottom-color: var(--line-strong); }
.topbar nav a.on { color: var(--fg); border-bottom-color: var(--fg); }
.search input { background: var(--bg-elev); border-color: var(--line-strong); border-radius: 6px; }
.container { max-width: 1240px; padding: 2rem 24px 4rem; }
.footer { padding: 2rem 24px 2.4rem; font-size: .82rem; line-height: 1.6; }
.cite-footer { background: none; border: 0; padding: 0; margin: 0 auto .7rem; text-align: center; max-width: 72ch; font-size: .84rem; }
.ai-note.foot { max-width: 72ch; }

/* sections: a hairline above, no box */
.panel { background: none; border: 0; border-top: 1px solid var(--line); border-radius: 0; box-shadow: none; padding: 1.5rem 0 1.3rem; overflow: visible; }
.panel + .panel { margin-top: 0; }
.panel > .eyebrow:first-child, .panel > .section-title:first-child { margin-top: 0; }
.eyebrow { font-size: .72rem; letter-spacing: .09em; color: var(--muted); margin-bottom: .8rem; }
.panel.head { border-top: 0; padding-top: .4rem; }
.panel.head h2 { font-size: 1.75rem; }
.panel.focus, section.panel.focus { border: 0; border-left: 2px solid var(--accent); background: var(--accent-soft); padding: .8rem 1.1rem; border-radius: 0; margin: 1rem 0 1.4rem; }
.panel.citebox { border-left: 2px solid var(--accent); border-top: 0; padding-left: 1.1rem; }
.panel.story h3 { font-size: 1.2rem; }
.focus { border-left-width: 2px; border-radius: 0; }
.crumbs { font-size: .8rem; letter-spacing: .01em; margin-bottom: .7rem; }
.section-title h2 { margin: 0; }

/* problem statement: an open section, the figure set beside the text */
details.statement { background: none; border: 0; border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); border-radius: 0; box-shadow: none; margin: 1.2rem 0 1.6rem; }
details.statement summary { padding: .8rem 0; font-size: 1.15rem; }
details.statement[open] summary { border-bottom: 0; }
details.statement .statement-body { padding: .2rem 0 1.2rem; }
.pfig { width: min(48%, 540px); margin: 0 0 1rem 2rem; padding: 0; background: none; border: 0; border-radius: 0; }
.pfig .figsvg { background: var(--bg-elev); border: 1px solid var(--line); border-radius: var(--radius-sm); padding: .4rem; }
.pfig figcaption { font-size: .86rem; line-height: 1.45; margin-top: .55rem; }
@media (max-width: 720px) { .pfig { width: 100%; margin: 0 0 1rem; } }

/* primer and history read as text, the analysis set off by a rule */
.idea { padding: 1.1rem 0 .6rem; }
.idea-head h4, .idea-head b { font-family: var(--serif); }
.idea-n { background: none; color: var(--accent); border: 1.5px solid var(--accent); width: 1.6rem; height: 1.6rem; }
.idea-analysis { background: none; border-left: 2px solid var(--line-strong); border-radius: 0; padding: .1rem 0 .1rem 1rem; margin: .7rem 0; font-size: .97rem; max-width: var(--measure); }

/* chips and badges: lighter */
.chip { border-radius: 4px; font-size: .76rem; padding: .16rem .5rem; }
.chip.assume, .chip.stronger, .chip.weaker, .chip.base { border: 0; }
.badge { border-radius: 3px; font-size: .66rem; letter-spacing: .06em; }
.pill { background: none; font-size: .78rem; }

/* home */
.home-hero { padding: 1rem 0 2rem; gap: 3rem; }
.home-hero h1 { font-weight: 600; letter-spacing: -.02em; }
.home-hero .subtitle { color: var(--fg); font-style: italic; font-weight: 400; }
.home-hero .tagline { font-size: 1.08rem; }
.hh-glance { border: 1px solid var(--line); border-radius: var(--radius); padding: 1.1rem 1.3rem; background: var(--bg-elev); }
.glance-nums b { font-weight: 600; }
.btn { border-radius: 6px; font-family: var(--sans); font-size: .86rem; padding: .42rem .95rem; }
.mgrid { gap: 1.6rem 2rem; }
.mcard { background: none; border: 0; border-top: 2px solid var(--mc, var(--accent)); border-radius: 0; padding: 1rem 0 .4rem; }
.mcard h3 { font-size: 1.45rem; }
.plink { border-radius: 4px; background: var(--bg-elev); border-color: var(--line); font-size: .8rem; padding: .16rem .5rem; }
.ovitem h4 { font-size: 1.1rem; }

/* cards (branches, perspectives on problem pages) */
.card { box-shadow: none; border-radius: var(--radius-sm); }
.card:hover { border-color: var(--line-strong); background: var(--bg-elev); }
.card:hover h3 { color: var(--accent); }

/* what is known */
.kcell { border-radius: 4px; }
.kname { font-size: 1.2rem; }

/* sidebar: wider, airier, a quiet active state */
@media (min-width: 901px) { .layout { grid-template-columns: 340px minmax(0, 1fr); gap: 2.4rem; } }
.sidebar { top: 4.4rem; padding-right: .6rem; }
.sidebar .tree a { font-family: var(--sans); font-size: .85rem; padding: .34rem .6rem; border-radius: 4px; border-left: 2px solid transparent; }
.tree ul { margin-left: .55rem; padding-left: .45rem; border-left-color: var(--line); }
.tree li { margin: .12rem 0; }
.tree a:hover { background: var(--bg-sunken); }
.tree a.active { background: var(--accent-soft); color: var(--accent); border-left-color: var(--accent); border-radius: 0 4px 4px 0; }
.tree a.active .delta { color: var(--accent); opacity: .8; }
.tree a.active .dot { outline: 0; }
.tree a.gapnode.active .t { color: var(--accent); }
.tree .delta { font-size: .73rem; margin-top: .1rem; }

/* tree of variants on the problem page */
.bigtree .node { border-radius: 4px; }
.bigtree li.standard > .node { box-shadow: none; border-width: 1.5px; }
.bigtree > li > .node { background: var(--bg-elev); }

/* tables */
th { font-size: .7rem; letter-spacing: .07em; }
td { line-height: 1.5; }

/* essays */
.essay { max-width: 70ch; }
.essay .prose { font-size: 1.07rem; line-height: 1.7; }
.essay .toc { background: none; border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); border-radius: 0; padding: .9rem 0; }
.essay-nav-link { border-radius: 6px; }

/* graph view and landscape keep their frames: they are drawings */
.gwrap { border-radius: 6px; }
.lcell { border-radius: 5px; }
.viewswitch { border-radius: 6px; font-family: var(--sans); }
.viewswitch a.on { background: var(--fg); color: var(--bg); }
.viewswitch a.on:hover { color: var(--bg); }
.land-tabs button, .land-tabs a { border-radius: 6px; }
.land-tabs button.on, .land-tabs a.on, .chip.on { background: var(--fg); border-color: var(--fg); color: var(--bg); }

/* open questions */
ol.prio > li { margin-bottom: 1.8rem; }
ol.prio > li::marker { font-weight: 600; }

@media (max-width: 900px) {
  .sidenav { border-radius: var(--radius-sm); }
  .layout { gap: 1.2rem; }
}
@media (max-width: 600px) {
  body { font-size: 16px; }
  h1, .home-hero h1 { font-size: 1.85rem; }
  .container { padding: 1.2rem 16px 3rem; }
  .topbar { padding: .55rem 16px; }
  .panel.head h2 { font-size: 1.4rem; }
}
details.statement + .panel, details.statement + section { border-top: 0; padding-top: .6rem; }
/* reading pages: one centred column, so the measure does not leave half the window empty */
#app[data-page="model"], #app[data-page="overview"], #app[data-page="open"], #app[data-page="cite"],
#app[data-page="acknowledgements"], #app[data-page="references"], #app[data-page="timeline"], #app[data-page="search"] { max-width: 940px; }
.panel.focus { max-width: calc(var(--measure) + 2.4rem); }
@media (max-width: 600px) {
  .section-title { flex-wrap: wrap; gap: .4rem .6rem; }
  /* notation tables as stacked entries */
  .nottable thead { display: none; }
  .nottable, .nottable tbody, .nottable tr, .nottable td { display: block; width: 100%; }
  .nottable tr { padding: .55rem 0; border-bottom: 1px solid var(--line); }
  .nottable td { border: 0; padding: .1rem 0; }
  .nottable td.sym { font-size: 1.05rem; }
  .nottable td:nth-child(3):not(:empty)::before { content: "Papers write: "; color: var(--muted); font-family: var(--sans); font-size: .78rem; }
  .nottable td:nth-child(4):not(:empty)::before { content: "Used in: "; color: var(--muted); font-family: var(--sans); font-size: .78rem; }
  .nottable td:empty { display: none; }
}
/* filled buttons: text in the page colour, so dark mode keeps its contrast */
.btn, .citebox button, .cite-actions button, .search-page button { color: var(--bg); }
.btn.ghost { color: var(--accent); }
.btn:hover { color: var(--bg); }
.btn.ghost:hover { color: var(--accent); }
.panel.gpanel, .panel.map { border-top: 0; padding-top: .4rem; }

/* ---------- problem page as a chapter: contents rail, then the sections in reading order ---------- */
.chapter { display: grid; grid-template-columns: minmax(0, 1fr); gap: 0 2.2rem; }
.chapter-toc { display: none; }
@media (min-width: 1180px) {
  .chapter { grid-template-columns: 11.5rem minmax(0, 1fr); }
  .chapter-toc { display: block; position: sticky; top: 4.6rem; align-self: start; padding-top: .3rem; font-family: var(--sans); }
  .chapter-toc h4 { font-size: .7rem; letter-spacing: .08em; text-transform: uppercase; color: var(--muted); margin: 0 0 .5rem; font-weight: 600; }
  .chapter-toc ol { list-style: none; margin: 0; padding: 0; border-left: 1px solid var(--line); }
  .chapter-toc li a { display: block; padding: .28rem 0 .28rem .8rem; margin-left: -1px; border-left: 2px solid transparent; color: var(--muted); font-size: .84rem; line-height: 1.3; text-decoration: none; }
  .chapter-toc li a:hover { color: var(--fg); border-left-color: var(--line-strong); }
  .chapter-toc li a.on { color: var(--accent); border-left-color: var(--accent); }
}
.chapter-body > section, .chapter-body > details { scroll-margin-top: 4.6rem; }
.chapter-body h2 .count { font-family: var(--sans); font-size: .9rem; font-weight: 500; }
.badge.std { background: var(--accent-soft); color: var(--accent); }
.openblock { margin: 1.1rem 0 0; max-width: var(--measure); }
.openblock h3 { font-size: 1rem; margin: 0 0 .3rem; font-family: var(--sans); font-weight: 600; }
.openblock ol { margin: 0; padding-left: 1.4rem; }
.openblock li { margin: .35rem 0; line-height: 1.55; }
.ovlist { list-style: none; padding: 0; margin: .4rem 0 0; max-width: var(--measure); }
.ovlist li { padding: .55rem 0; border-top: 1px solid var(--line); line-height: 1.5; }
.ovlist li:first-child { border-top: 0; }
.ovlist li a { font-weight: 600; margin-right: .35rem; }
.treefold > summary { cursor: pointer; font-family: var(--sans); font-size: .92rem; color: var(--accent); padding: .3rem 0 .6rem; }
.treefold[open] > summary { margin-bottom: .4rem; }

/* light/dark switch in the top bar */
.theme-toggle { display: inline-flex; align-items: center; justify-content: center; width: 1.7rem; height: 1.7rem; margin: -.15rem 0; padding: 0; border: 1px solid var(--line-strong); border-radius: 50%; background: var(--bg-elev); color: var(--muted); font: 1rem/1 var(--sans); cursor: pointer; }
.theme-toggle:hover, .theme-toggle:focus-visible { color: var(--fg); border-color: var(--muted); }

/* last-updated tag on the home page */
.updated { font-family: var(--sans); font-size: .82rem; color: var(--muted); margin: -.2rem 0 1rem; }
.updated-tag { display: inline-block; font-size: .68rem; font-weight: 600; text-transform: uppercase; letter-spacing: .07em; color: var(--accent); border: 1px solid currentColor; border-radius: 3px; padding: .05rem .4rem; margin-right: .35rem; vertical-align: .08em; }