/* physics.ndot.io: light mode only, in the palette of ndot.io (see SPEC.md, "Visual design"). */
:root {
  --night: #181B21;
  --ink: #22252B;
  --paper: #EFECE6;
  --chalk: #F7F5F0;
  --soft: #F3F1EC;
  --soft-muted: #B4AEA4;
  --muted: #66615A;
  --blue: #263A73;
  --oak: #C9A97E;
  --line: rgba(34, 37, 43, .12);
  --st-verified: #3F6B4E;
  --st-open: #66615A;
  --st-draft: #74613F;
  --st-error: #9B3B2E;
  --st-affected: #A0521C;
  --st-needs-decision: #5B3F7A;
  --display: 'Geologica', system-ui, sans-serif;
  --text: 'Manrope', system-ui, sans-serif;
  --serif: 'Noto Serif Display', Georgia, serif;
  --mono: 'Geist Mono', ui-monospace, monospace;
  --gutter: clamp(16px, 4vw, 40px);
}

* { box-sizing: border-box; }
html { background: var(--paper); }
body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font: 400 17px/1.7 var(--text);
  -webkit-font-smoothing: antialiased;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}
a { color: var(--blue); }

/* Status colours: .st-<status> sets --st for badges and dots. */
.st-verified { --st: var(--st-verified); }
.st-open { --st: var(--st-open); }
.st-draft { --st: var(--st-draft); }
.st-error { --st: var(--st-error); }
.st-affected { --st: var(--st-affected); }
.st-needs-decision { --st: var(--st-needs-decision); }
.badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font: 500 11px/1 var(--mono);
  letter-spacing: .06em;
  text-transform: uppercase;
  color: var(--st, var(--st-open));
  white-space: nowrap;
}
.badge::before, .dot {
  content: "";
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--st, var(--st-open));
  flex: none;
}
.crumb {
  font: 400 11px/1.4 var(--mono);
  letter-spacing: .08em;
  text-transform: uppercase;
  color: var(--muted);
}

/* Header and footer: dark, like the main site. */
.top {
  background: var(--night);
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 12px 32px;
  padding: 16px var(--gutter);
}
.brand { white-space: nowrap; }
.brand a { text-decoration: none; }
.brand-main { font: 800 20px/1 var(--display); color: #FFFFFF; }
.brand-sub { font: italic 400 21px/1 var(--serif); color: var(--oak); }
.top-nav { display: flex; flex-wrap: wrap; gap: 8px 22px; margin-left: auto; }
.top-nav a { color: var(--soft-muted); font: 600 14px/1.4 var(--text); text-decoration: none; }
.top-nav a:hover, .top-nav a.active { color: #FFFFFF; }
.foot {
  background: var(--night);
  display: flex;
  justify-content: space-between;
  gap: 16px;
  padding: 18px var(--gutter);
  font: 400 11px/1.4 var(--mono);
  letter-spacing: .08em;
  text-transform: uppercase;
  color: var(--soft-muted);
}
.foot a { color: var(--oak); text-decoration: none; }

/* Page body: sidebar and reading column. */
.shell {
  flex: 1;
  width: 100%;
  max-width: 1240px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: 260px minmax(0, 1fr);
  gap: clamp(24px, 4vw, 56px);
  padding: 36px var(--gutter) 72px;
}
.shell.wide { grid-template-columns: minmax(0, 1fr); }
main { min-width: 0; max-width: 800px; }

.side { font-size: 14px; line-height: 1.4; }
.side-title {
  display: block;
  font: 800 16px/1.3 var(--display);
  color: var(--ink);
  text-decoration: none;
}
.side-folder { font: 400 11px/1.4 var(--mono); color: var(--muted); margin: 4px 0 16px; }
.side-nav { position: sticky; top: 16px; }
.side-nav a {
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 5px 8px;
  border-radius: 6px;
  color: var(--ink);
  text-decoration: none;
}
.side-nav a:hover { background: rgba(34, 37, 43, .05); }
.side-nav a.active { background: var(--chalk); font-weight: 700; box-shadow: inset 0 0 0 1px var(--line); }
.side-nav .num { font: 400 11px/1 var(--mono); color: var(--muted); min-width: 18px; }
.side-nav .name { flex: 1; }
.side-nav .dot { align-self: center; }
.side-nav .sep { border-top: 1px solid var(--line); margin: 10px 8px; }
.menu-toggle { position: absolute; opacity: 0; pointer-events: none; }
.menu-label { display: none; }

/* Package header and sub-navigation. */
.pkg-head { border-bottom: 1px solid var(--line); padding-bottom: 14px; margin-bottom: 28px; }
.pkg-title {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 6px 14px;
  margin: 6px 0 12px;
  font: 800 22px/1.25 var(--display);
}
.pkg-num { font: 400 15px/1 var(--mono); color: var(--muted); }
.cause { font: 400 12px/1 var(--mono); color: var(--st-affected); }
.subnav { display: flex; flex-wrap: wrap; gap: 8px 24px; font-size: 14px; line-height: 1.6; }
.subnav .group { display: inline-flex; flex-wrap: wrap; align-items: baseline; gap: 4px; }
.subnav .label {
  font: 500 11px/1 var(--mono);
  letter-spacing: .06em;
  text-transform: uppercase;
  color: var(--muted);
  margin-right: 4px;
}
.subnav a { color: var(--blue); text-decoration: none; padding: 1px 7px; border-radius: 5px; }
.subnav a:hover { background: rgba(38, 58, 115, .06); }
.subnav a.active { background: var(--chalk); box-shadow: inset 0 0 0 1px var(--line); }
.subnav a.is-current { font-weight: 700; }
.subnav a.is-current::after {
  content: "current";
  font: 500 9px/1 var(--mono);
  letter-spacing: .06em;
  text-transform: uppercase;
  color: var(--muted);
  margin-left: 5px;
  vertical-align: 2px;
}
.meta-line { font-size: 14px; color: var(--muted); margin: -12px 0 24px; }
.meta-line strong { color: var(--ink); font-weight: 700; }
.verdict { color: var(--ink); font-weight: 600; }

/* Editorial texts (site/seo/): written for the site, marked as such. */
.editorial { font-size: 15px; line-height: 1.6; color: var(--ink); margin: -2px 0 12px; max-width: 680px; }
.editorial-label {
  font: 500 10px/1 var(--mono);
  letter-spacing: .08em;
  text-transform: uppercase;
  color: var(--muted);
  border: 1px solid var(--line);
  border-radius: 4px;
  padding: 2px 5px;
  margin-right: 6px;
  vertical-align: 2px;
}

/* Subproject start page: summary and package list above the base problem. */
.sub-intro { margin-bottom: 36px; }
.sub-title { font: 800 clamp(26px, 3vw, 34px)/1.2 var(--display); margin: 6px 0 14px; letter-spacing: -.01em; }
.sub-intro .editorial, .sub-description { font-size: 17px; margin-bottom: 22px; }
.sub-description { color: var(--muted); }
.report-link {
  display: flex;
  flex-direction: column;
  gap: 4px;
  background: var(--chalk);
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 14px 18px;
  margin: 0 0 24px;
  color: var(--ink);
  text-decoration: none;
}
.report-link:hover { border-color: rgba(38, 58, 115, .35); }
.report-label { font: 800 17px/1.3 var(--display); color: var(--blue); }
.report-text { font-size: 14px; color: var(--muted); }
.pkg-list { list-style: none; margin: 0; padding: 0; border-top: 1px solid var(--line); }
.pkg-list li { border-bottom: 1px solid var(--line); }
.pkg-list a { display: flex; align-items: baseline; gap: 12px; padding: 10px 4px; color: var(--ink); text-decoration: none; }
.pkg-list a:hover { background: rgba(34, 37, 43, .04); }
.pkg-list .num { font: 400 11px/1 var(--mono); color: var(--muted); min-width: 20px; }
.pkg-line { flex: 1; display: flex; flex-direction: column; gap: 2px; }
.pkg-label { font-weight: 700; }
.pkg-sentence { font-size: 14px; line-height: 1.5; color: var(--muted); }

/* Rendered Markdown. */
.md-source {
  white-space: pre-wrap;
  word-wrap: break-word;
  font: 400 13px/1.6 var(--mono);
  background: var(--chalk);
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 16px;
}
.js .md-source { display: none; }
.md-render h1 { font: 800 clamp(26px, 3vw, 32px)/1.2 var(--display); margin: 0 0 20px; letter-spacing: -.01em; }
.md-render h2 { font: 800 22px/1.3 var(--display); margin: 40px 0 12px; }
.md-render h3 { font: 700 18px/1.35 var(--display); margin: 30px 0 10px; }
.md-render h4 { font: 700 16px/1.4 var(--display); margin: 24px 0 8px; }
.md-render p, .md-render ul, .md-render ol { margin: 0 0 14px; }
.md-render li { margin: 3px 0; }
.md-render li > p { margin: 0 0 6px; }
.md-render hr { border: 0; border-top: 1px solid var(--line); margin: 28px 0; }
.md-render blockquote { margin: 0 0 14px; padding: 2px 16px; border-left: 3px solid var(--line); color: var(--muted); }
.md-render code { font: 400 .86em var(--mono); background: var(--chalk); padding: 1px 5px; border-radius: 4px; }
.md-render pre, .file-text {
  background: var(--chalk);
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 12px 16px;
  overflow-x: auto;
  font: 400 13px/1.55 var(--mono);
}
.md-render pre code { background: none; padding: 0; font-size: inherit; }
.md-render table {
  display: block;
  overflow-x: auto;
  border-collapse: collapse;
  margin: 0 0 18px;
  font-size: 15px;
  line-height: 1.5;
}
.md-render th, .md-render td { border: 1px solid var(--line); padding: 6px 10px; text-align: left; vertical-align: top; }
.md-render th { background: var(--chalk); font-weight: 700; }
.math-block { overflow-x: auto; overflow-y: hidden; margin: 4px 0 14px; padding: 0 4px; border-radius: 6px; }
.math-block:target { background: rgba(38, 58, 115, .08); }
.math-block .katex-display { margin: .7em 0; }
.katex { font-size: 1.08em; }
.math-error { color: var(--st-error); }

/* Equation citations: the current version is the main link, other versions follow as small superscripts. */
a.cite { text-decoration: none; border-bottom: 1px solid rgba(38, 58, 115, .3); }
a.cite:hover { border-bottom-color: var(--blue); }
a.cite.cite-current { font-weight: 700; }
.cite-versions { font: 500 10px/1 var(--mono); margin-left: 2px; }
.cite-versions a { color: var(--muted); text-decoration: none; margin-right: 3px; }
.cite-versions a:hover { color: var(--blue); }

/* Code view. */
.file { margin: 0 0 32px; }
.file-head {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  font: 500 12px/1.4 var(--mono);
  color: var(--muted);
  margin-bottom: 6px;
}
.file-head span:first-child { color: var(--ink); }
.file-text { max-height: 640px; overflow: auto; margin: 0; }
.file-image { display: block; max-width: 100%; border: 1px solid var(--line); border-radius: 8px; background: #FFFFFF; }
.file-md { background: var(--chalk); border: 1px solid var(--line); border-radius: 8px; padding: 16px 20px; }

/* Start page. */
.home { max-width: 760px; }
.home-title { font: 800 clamp(30px, 4vw, 42px)/1.15 var(--display); margin: 8px 0 14px; letter-spacing: -.01em; }
.home-lead { font-size: 19px; color: var(--ink); margin: 0 0 32px; }
.cards { display: grid; gap: 16px; }
.card {
  display: block;
  background: var(--chalk);
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 20px 24px;
  color: inherit;
  text-decoration: none;
}
.card:hover { border-color: rgba(38, 58, 115, .35); }
.card h2 { font: 800 22px/1.25 var(--display); margin: 6px 0 8px; }
.card p { margin: 0 0 14px; color: var(--muted); font-size: 16px; }
.counts { display: flex; flex-wrap: wrap; gap: 8px 18px; }

@media (max-width: 900px) {
  .shell { grid-template-columns: minmax(0, 1fr); padding-top: 20px; }
  .side { border-bottom: 1px solid var(--line); padding-bottom: 12px; }
  .side-nav { display: none; position: static; margin-top: 8px; }
  .menu-label {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    font: 500 11px/1 var(--mono);
    letter-spacing: .06em;
    text-transform: uppercase;
    color: var(--blue);
    border: 1px solid var(--line);
    border-radius: 6px;
    padding: 8px 10px;
    cursor: pointer;
  }
  .menu-label::after { content: "+"; }
  .menu-toggle:checked ~ .menu-label::after { content: "\2212"; }
  .menu-toggle:checked ~ .side-nav { display: block; }
  .menu-toggle:focus-visible + .menu-label { outline: 2px solid var(--blue); }
  .top-nav { margin-left: 0; }
  body { font-size: 16px; }
}