/* ==========================================================================
   CONNECTIVITY SYSTEM — server-rendered document pages
   Topic pages, About, Methodology, Sources, Contribute, 404, 500.

   Loaded after main.css and reuses its custom properties, so light/dark and
   the palette stay in sync. main.css owns the 3-panel app; this file owns
   everything that is a readable document instead.
   ========================================================================== */

.docbody {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--font);
  line-height: 1.65;
  /* main.css locks the app to the viewport; documents must scroll */
  height: auto;
  overflow: auto;
}

/* ------------------------------------------------------------------ head -- */
.dochead {
  position: sticky;
  top: 0;
  z-index: 40;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  height: var(--topbar-h);
  padding: 0 clamp(16px, 4vw, 40px);
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--line);
}

.doc-brand {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  color: var(--ink);
}
.doc-brand .brand-mark { width: 30px; height: 30px; flex: none; }
.doc-brand span { display: flex; flex-direction: column; line-height: 1.2; }
.doc-brand strong { font-size: 15px; font-weight: 700; letter-spacing: -.01em; }
.doc-brand em {
  font-style: normal;
  font-size: 11px;
  color: var(--ink-3);
  letter-spacing: .02em;
}

.doc-nav { display: flex; align-items: center; gap: 4px; }
.doc-nav a {
  padding: 7px 12px;
  border-radius: var(--r-sm);
  color: var(--ink-2);
  text-decoration: none;
  font-size: 13.5px;
  font-weight: 500;
  white-space: nowrap;
}
.doc-nav a:hover { background: var(--bg-3); color: var(--ink); }

/* ----------------------------------------------------------- breadcrumbs -- */
.doc-crumbs {
  max-width: 1080px;
  margin: 0 auto;
  padding: 18px clamp(16px, 4vw, 40px) 0;
  font-size: 13px;
}
.doc-crumbs ol {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 6px;
  margin: 0;
  padding: 0;
  list-style: none;
}
.doc-crumbs li + li::before {
  content: '›';
  margin-right: 6px;
  color: var(--ink-3);
}
.doc-crumbs a { color: var(--ink-3); text-decoration: none; }
.doc-crumbs a:hover { color: var(--accent); text-decoration: underline; }
.doc-crumbs [aria-current] { color: var(--ink-2); font-weight: 500; }

/* ------------------------------------------------------------------ body -- */
.doc {
  display: block;
  max-width: 1080px;
  margin: 0 auto;
  padding: 28px clamp(16px, 4vw, 40px) 80px;
  --doc-accent: var(--accent);
}

.doc h1 {
  font-size: clamp(28px, 4.4vw, 42px);
  line-height: 1.15;
  letter-spacing: -.025em;
  margin: 0 0 10px;
  font-weight: 800;
}
.doc h2 {
  font-size: clamp(19px, 2.4vw, 24px);
  letter-spacing: -.015em;
  margin: 0 0 6px;
  font-weight: 700;
}
.doc h3 { font-size: 16px; font-weight: 650; margin: 22px 0 6px; }
.doc p  { margin: 0 0 14px; color: var(--ink-2); }
.doc a  { color: var(--accent); }

.doc > .t-article > .t-sec,
.doc > .t-sec {
  padding-top: 34px;
  margin-top: 34px;
  border-top: 1px solid var(--line);
}
.t-sec-sub { font-size: 13.5px; color: var(--ink-3); margin: 0 0 16px; }

/* ------------------------------------------------------------------ hero -- */
.t-hero {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 32px;
  align-items: start;
  padding-bottom: 4px;
}
.t-kicker {
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: .09em;
  font-weight: 650;
  color: var(--doc-accent);
  margin: 0 0 8px;
}
.t-bn { font-size: 18px; color: var(--ink-2); margin: -4px 0 10px; }
.t-lede { font-size: 17px; line-height: 1.6; color: var(--ink-2); max-width: 62ch; }
.t-actions { margin: 20px 0 0; }

.primary-btn {
  display: inline-block;
  padding: 10px 18px;
  border-radius: var(--r-md);
  background: var(--doc-accent);
  color: #06101F;
  font-weight: 650;
  font-size: 14px;
  text-decoration: none;
  border: 0;
  cursor: pointer;
}
.primary-btn:hover { filter: brightness(1.08); }

.t-tiles {
  display: grid;
  grid-template-columns: repeat(2, minmax(96px, 1fr));
  gap: 10px;
  margin: 0;
}
.t-tiles > div {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: var(--r-md);
  padding: 12px 14px;
}
.t-tiles dt {
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: .06em;
  color: var(--ink-3);
  margin-bottom: 3px;
}
.t-tiles dd {
  margin: 0;
  font-size: 22px;
  font-weight: 700;
  font-family: var(--mono);
  color: var(--ink);
}

/* ----------------------------------------------------------------- cards -- */
.t-cards {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  gap: 12px;
  list-style: none;
  margin: 0;
  padding: 0;
}
.t-cards a {
  display: flex;
  flex-direction: column;
  gap: 4px;
  height: 100%;
  padding: 14px 16px;
  background: var(--panel);
  border: 1px solid var(--line);
  border-left: 3px solid var(--doc-accent);
  border-radius: var(--r-md);
  text-decoration: none;
  color: var(--ink);
}
.t-cards a:hover { background: var(--panel-2); border-color: var(--line-2); }
.t-cards strong { font-size: 14.5px; font-weight: 650; }
.t-cards span { font-size: 12.5px; color: var(--ink-3); line-height: 1.5; }
.t-cards em {
  font-style: normal;
  font-size: 11px;
  color: var(--ink-3);
  font-family: var(--mono);
  margin-top: auto;
  padding-top: 4px;
}

/* --------------------------------------------------------- linked topics -- */
.t-links { list-style: none; margin: 0; padding: 0; display: grid; gap: 10px; }
.t-links li {
  padding: 13px 16px;
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: var(--r-md);
}
.t-links li.is-cross { border-left: 3px solid var(--accent-2); }

.tl-head { display: flex; align-items: center; flex-wrap: wrap; gap: 8px; }
.tl-head a { font-weight: 650; font-size: 14.5px; text-decoration: none; }
.tl-head a:hover { text-decoration: underline; }
.tl-disc { font-size: 11.5px; color: var(--ink-3); }

.tl-badge {
  font-size: 10px;
  text-transform: uppercase;
  letter-spacing: .05em;
  font-weight: 700;
  padding: 2px 7px;
  border-radius: 999px;
  margin-left: auto;
}
.tl-verified { background: color-mix(in srgb, var(--good) 18%, transparent); color: var(--good); }
.tl-derived  { background: color-mix(in srgb, var(--warn) 18%, transparent); color: var(--warn); }
.tl-proposed { background: var(--bg-3); color: var(--ink-3); }

.tl-meter {
  height: 3px;
  background: var(--bg-3);
  border-radius: 999px;
  margin: 9px 0 0;
  overflow: hidden;
}
.tl-meter i { display: block; height: 100%; background: var(--doc-accent); }
.tl-why { font-size: 13px; color: var(--ink-2); margin: 9px 0 0; }

/* ---------------------------------------------------------------- tables -- */
.t-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 13.5px;
}
.t-table th, .t-table td {
  text-align: left;
  padding: 10px 12px;
  border-bottom: 1px solid var(--line);
  vertical-align: top;
}
.t-table thead th {
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: .06em;
  color: var(--ink-3);
  font-weight: 650;
  border-bottom-color: var(--line-2);
}
.t-table tbody th { font-weight: 600; color: var(--ink); }
.t-table tbody td { color: var(--ink-2); }
.t-table small { display: block; font-size: 11.5px; color: var(--ink-3); font-weight: 400; }
.t-table tbody tr:hover { background: var(--panel-2); }

.lic, .dm, .rel {
  display: inline-block;
  font-size: 10.5px;
  text-transform: uppercase;
  letter-spacing: .04em;
  font-weight: 700;
  padding: 2px 7px;
  border-radius: 999px;
  white-space: nowrap;
}
.lic-free, .lic-open_source { background: color-mix(in srgb, var(--good) 16%, transparent); color: var(--good); }
.lic-freemium, .lic-academic, .lic-trial { background: color-mix(in srgb, var(--warn) 16%, transparent); color: var(--warn); }
.lic-commercial { background: var(--bg-3); color: var(--ink-3); }

.dm-very_high { background: color-mix(in srgb, var(--good) 20%, transparent); color: var(--good); }
.dm-high      { background: color-mix(in srgb, var(--good) 13%, transparent); color: var(--good); }
.dm-moderate  { background: color-mix(in srgb, var(--warn) 15%, transparent); color: var(--warn); }
.dm-low       { background: var(--bg-3); color: var(--ink-3); }

.rel-primary   { background: color-mix(in srgb, var(--good) 16%, transparent); color: var(--good); }
.rel-secondary { background: var(--bg-3); color: var(--ink-3); }
.rel-tertiary  { background: color-mix(in srgb, var(--bad) 14%, transparent); color: var(--bad); }

/* ----------------------------------------------------------------- chips -- */
.t-chips {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  list-style: none;
  margin: 0;
  padding: 0;
}
.t-chips li {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 5px 12px;
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 999px;
  font-size: 13px;
}
.t-chips a { text-decoration: none; }
.t-chips a:hover { text-decoration: underline; }
.t-chips em {
  font-style: normal;
  font-size: 10.5px;
  color: var(--ink-3);
  font-family: var(--mono);
}

/* --------------------------------------------------------------- sources -- */
.t-sources { margin: 0; padding-left: 20px; font-size: 13.5px; }
.t-sources li { margin-bottom: 9px; color: var(--ink-2); }
.t-sources .rel { margin-left: 6px; }

.t-caveat {
  font-size: 12.5px;
  color: var(--ink-3);
  border-left: 2px solid var(--warn);
  padding: 8px 0 8px 12px;
  margin-top: 16px;
}
.t-empty {
  background: var(--panel);
  border: 1px dashed var(--line-2);
  border-radius: var(--r-md);
  padding: 18px 20px;
  color: var(--ink-3);
  font-size: 13.5px;
  margin: 0;
}

/* -------------------------------------------------------- prose / static -- */
.doc-prose { max-width: 72ch; }
.doc-prose h2 { margin-top: 34px; }
.doc-prose ul, .doc-prose ol { color: var(--ink-2); padding-left: 22px; margin: 0 0 14px; }
.doc-prose li { margin-bottom: 7px; }
.doc-prose blockquote {
  margin: 18px 0;
  padding: 2px 0 2px 16px;
  border-left: 3px solid var(--doc-accent);
  color: var(--ink-2);
  font-size: 15px;
}
.doc-prose code {
  font-family: var(--mono);
  font-size: .9em;
  background: var(--bg-3);
  padding: 1px 5px;
  border-radius: 4px;
}
.doc-lede {
  font-size: 17.5px;
  line-height: 1.6;
  color: var(--ink-2);
  max-width: 62ch;
  margin-bottom: 26px;
}

/* ------------------------------------------------------------------ form -- */
.doc-form { display: grid; gap: 14px; max-width: 560px; margin-top: 22px; }
.doc-form label { display: grid; gap: 5px; font-size: 13px; font-weight: 600; color: var(--ink-2); }
.doc-form input, .doc-form select, .doc-form textarea {
  font: inherit;
  font-size: 14px;
  padding: 9px 12px;
  background: var(--panel);
  color: var(--ink);
  border: 1px solid var(--line-2);
  border-radius: var(--r-sm);
  width: 100%;
}
.doc-form textarea { min-height: 130px; resize: vertical; line-height: 1.55; }
.doc-form input:focus, .doc-form select:focus, .doc-form textarea:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--ring);
}
.doc-form .hint { font-weight: 400; font-size: 12px; color: var(--ink-3); }

.doc-note {
  padding: 14px 18px;
  border-radius: var(--r-md);
  font-size: 13.5px;
  margin: 0 0 20px;
}
.doc-note.ok   { background: color-mix(in srgb, var(--good) 12%, transparent); color: var(--good); }
.doc-note.bad  { background: color-mix(in srgb, var(--bad) 12%, transparent);  color: var(--bad); }

/* ----------------------------------------------------------------- error -- */
.doc-error { text-align: center; padding: 70px 0 40px; max-width: 560px; margin: 0 auto; }
.doc-error .code {
  font-family: var(--mono);
  font-size: clamp(64px, 14vw, 110px);
  font-weight: 700;
  line-height: 1;
  color: var(--line-2);
  letter-spacing: -.04em;
}
.doc-error h1 { font-size: 26px; margin: 10px 0 12px; }
.doc-error .doc-actions { display: flex; gap: 10px; justify-content: center; flex-wrap: wrap; margin-top: 24px; }
.ghost-btn {
  display: inline-block;
  padding: 10px 18px;
  border-radius: var(--r-md);
  border: 1px solid var(--line-2);
  color: var(--ink-2);
  text-decoration: none;
  font-size: 14px;
  font-weight: 600;
}
.ghost-btn:hover { background: var(--bg-3); color: var(--ink); }

/* ---------------------------------------------------------------- footer -- */
.docfoot {
  border-top: 1px solid var(--line);
  background: var(--panel);
  padding: 40px clamp(16px, 4vw, 40px) 26px;
}
.df-grid {
  max-width: 1080px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 30px;
}
.df-grid h4 {
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: .07em;
  color: var(--ink-3);
  margin: 0 0 10px;
}
.df-grid strong { font-size: 14px; display: block; margin-bottom: 8px; }
.df-grid p { font-size: 12.5px; color: var(--ink-3); margin: 0; max-width: 40ch; }
.df-grid a {
  display: block;
  font-size: 13px;
  color: var(--ink-2);
  text-decoration: none;
  margin-bottom: 6px;
}
.df-grid a:hover { color: var(--accent); }

.df-bottom {
  max-width: 1080px;
  margin: 30px auto 0;
  padding-top: 18px;
  border-top: 1px solid var(--line);
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 10px;
  font-size: 12px;
  color: var(--ink-3);
}
.df-bottom a { color: var(--ink-3); }

/* ----------------------------------------------------------- responsive -- */
@media (max-width: 860px) {
  .t-hero { grid-template-columns: 1fr; gap: 22px; }
  .t-tiles { grid-template-columns: repeat(auto-fit, minmax(90px, 1fr)); width: 100%; }
  .df-grid { grid-template-columns: 1fr 1fr; }
}
@media (max-width: 620px) {
  .doc-nav a { display: none; }
  .doc-nav a:first-child { display: inline-block; }
  .df-grid { grid-template-columns: 1fr; gap: 22px; }
  .t-table { font-size: 12.5px; }
  .t-table th, .t-table td { padding: 8px 8px; }
}

@media print {
  .dochead, .docfoot, .doc-crumbs, .t-actions { display: none; }
  .doc { max-width: none; padding: 0; }
  .doc a { color: inherit; text-decoration: underline; }
}