/* TAP protocol documentation
   Visual language: authorization. Indigo carries ordinary state,
   warm gold carries authority. Nothing else uses gold. */

*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body, h1, h2, h3, h4, p, ul, ol, dl, dd, figure, pre, table { margin: 0; }
ul, ol { padding: 0; }
img, svg { max-width: 100%; }

:root {
  color-scheme: light dark;

  --bg: #f4f5fb;
  --bg-deep: #e8ebf7;
  --surface: #ffffff;
  --surface-2: #eceffa;
  --ink: #12162f;
  --ink-2: #3a406b;
  --ink-muted: #4c5279;
  --line: #d0d5ec;
  --line-strong: #aeb6d8;

  --indigo: #2f3a8f;
  --indigo-soft: #e2e6fb;
  --indigo-line: #8f9ad8;
  --on-indigo: #ffffff;

  --gold: #7a5200;
  --gold-soft: #fdf3d8;
  --gold-line: #b98a1e;
  --gold-strong: #8a5b00;

  --danger: #8c1d1d;
  --danger-soft: #fbe6e6;
  --danger-line: #c46a6a;
  --ok: #145239;
  --ok-soft: #e0f2ea;
  --ok-line: #5fa588;

  --focus: #1c2a7a;

  --radius: 10px;
  --radius-sm: 6px;
  --measure: 74ch;

  --font-text: ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto,
    "Helvetica Neue", Arial, "Noto Sans", sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas,
    "Liberation Mono", "Courier New", monospace;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #0b0e26;
    --bg-deep: #070919;
    --surface: #141935;
    --surface-2: #1c2246;
    --ink: #e9ebf9;
    --ink-2: #c3c9ea;
    --ink-muted: #a9b0d6;
    --line: #2b3260;
    --line-strong: #414a83;

    --indigo: #9db3ff;
    --indigo-soft: #1a2150;
    --indigo-line: #4a58a8;
    --on-indigo: #0b0e26;

    --gold: #ffcb5c;
    --gold-soft: #2c2310;
    --gold-line: #8a6a1e;
    --gold-strong: #ffd782;

    --danger: #ff9f9f;
    --danger-soft: #35171a;
    --danger-line: #8c4448;
    --ok: #7fd8ae;
    --ok-soft: #102b21;
    --ok-line: #35755a;

    --focus: #ffcb5c;
  }
}

:root[data-theme="dark"] {
  --bg: #0b0e26;
  --bg-deep: #070919;
  --surface: #141935;
  --surface-2: #1c2246;
  --ink: #e9ebf9;
  --ink-2: #c3c9ea;
  --ink-muted: #a9b0d6;
  --line: #2b3260;
  --line-strong: #414a83;

  --indigo: #9db3ff;
  --indigo-soft: #1a2150;
  --indigo-line: #4a58a8;
  --on-indigo: #0b0e26;

  --gold: #ffcb5c;
  --gold-soft: #2c2310;
  --gold-line: #8a6a1e;
  --gold-strong: #ffd782;

  --danger: #ff9f9f;
  --danger-soft: #35171a;
  --danger-line: #8c4448;
  --ok: #7fd8ae;
  --ok-soft: #102b21;
  --ok-line: #35755a;

  --focus: #ffcb5c;
}

body {
  background: var(--bg);
  color: var(--ink);
  font-family: var(--font-text);
  font-size: 16px;
  line-height: 1.65;
  overflow-wrap: break-word;
}

a { color: var(--indigo); text-underline-offset: 3px; }
a:hover { text-decoration-thickness: 2px; }

:focus-visible {
  outline: 3px solid var(--focus);
  outline-offset: 2px;
  border-radius: 3px;
}

.skip {
  position: absolute;
  left: -9999px;
  top: 0;
  background: var(--surface);
  color: var(--ink);
  padding: 10px 16px;
  border: 2px solid var(--focus);
  border-radius: 0 0 var(--radius) 0;
  z-index: 60;
}
.skip:focus { left: 0; }

/* ---------- shell ---------- */

.shell { width: 100%; max-width: 1240px; margin: 0 auto; padding: 0 18px; }

.masthead {
  position: sticky;
  top: 0;
  z-index: 40;
  background: var(--bg-deep);
  border-bottom: 1px solid var(--line);
}

.masthead-in {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 12px 18px;
  padding-block: 10px;
}

.seal {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  letter-spacing: 0.01em;
  text-decoration: none;
  color: var(--ink);
  flex: 0 0 auto;
}
.seal svg { display: block; }
.seal small {
  display: block;
  font-weight: 500;
  font-size: 11px;
  letter-spacing: 0.09em;
  text-transform: uppercase;
  color: var(--ink-muted);
}

.mainnav { flex: 1 1 320px; }
.mainnav ul {
  display: flex;
  flex-wrap: wrap;
  gap: 2px 4px;
  list-style: none;
}
.mainnav a {
  display: block;
  padding: 5px 10px;
  border-radius: var(--radius-sm);
  text-decoration: none;
  color: var(--ink-2);
  font-size: 14px;
  font-weight: 600;
}
.mainnav a:hover { background: var(--surface-2); color: var(--ink); }
.mainnav a[aria-current="page"] {
  background: var(--indigo-soft);
  color: var(--indigo);
  box-shadow: inset 0 -2px 0 var(--indigo);
}

.tools { display: flex; align-items: center; gap: 8px; flex: 0 0 auto; }

.searchbox { position: relative; }
.searchbox input {
  font: inherit;
  font-size: 14px;
  width: 190px;
  max-width: 46vw;
  padding: 6px 10px;
  color: var(--ink);
  background: var(--surface);
  border: 1px solid var(--line-strong);
  border-radius: var(--radius-sm);
}
.searchbox input::placeholder { color: var(--ink-muted); }

.hitlist {
  position: absolute;
  right: 0;
  top: calc(100% + 6px);
  width: min(440px, 88vw);
  max-height: 62vh;
  overflow-y: auto;
  background: var(--surface);
  border: 1px solid var(--line-strong);
  border-radius: var(--radius);
  box-shadow: 0 14px 34px rgba(5, 8, 30, 0.28);
  list-style: none;
  padding: 6px;
  z-index: 50;
}
.hitlist:empty { display: none; }
.hitlist li + li { margin-top: 2px; }
.hitlist a {
  display: block;
  padding: 8px 10px;
  border-radius: var(--radius-sm);
  text-decoration: none;
  color: var(--ink);
}
.hitlist a:hover, .hitlist a:focus-visible { background: var(--indigo-soft); }
.hitlist b { display: block; font-size: 14px; color: var(--indigo); }
.hitlist span { display: block; font-size: 13px; color: var(--ink-muted); }
.hitlist .note { padding: 10px; font-size: 14px; color: var(--ink-muted); }

.themebtn {
  font: inherit;
  font-size: 13px;
  font-weight: 600;
  padding: 6px 11px;
  color: var(--ink-2);
  background: var(--surface);
  border: 1px solid var(--line-strong);
  border-radius: var(--radius-sm);
  cursor: pointer;
}
.themebtn:hover { color: var(--ink); border-color: var(--indigo); }

/* ---------- page frame ---------- */

.frame { display: block; padding: 26px 0 56px; }

@media (min-width: 1000px) {
  .frame {
    display: grid;
    grid-template-columns: 224px minmax(0, 1fr);
    gap: 40px;
    align-items: start;
  }
}

.sidenav {
  display: none;
  position: sticky;
  top: 72px;
  max-height: calc(100vh - 96px);
  overflow-y: auto;
  font-size: 14px;
  border-left: 2px solid var(--line);
  padding-left: 14px;
}
@media (min-width: 1000px) { .sidenav { display: block; } }
.sidenav p {
  font-size: 11px;
  letter-spacing: 0.09em;
  text-transform: uppercase;
  color: var(--ink-muted);
  font-weight: 700;
  margin-bottom: 8px;
}
.sidenav ul { list-style: none; }
.sidenav li + li { margin-top: 2px; }
.sidenav a {
  display: block;
  padding: 3px 0;
  text-decoration: none;
  color: var(--ink-2);
}
.sidenav a:hover { color: var(--indigo); text-decoration: underline; }

.doc { min-width: 0; }
.doc > * + * { margin-top: 20px; }

/* ---------- typography ---------- */

.kicker {
  font-size: 11px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  font-weight: 700;
  color: var(--ink-muted);
}

h1 {
  font-size: clamp(28px, 5vw, 42px);
  line-height: 1.15;
  letter-spacing: -0.02em;
  font-weight: 800;
}
h2 {
  font-size: clamp(21px, 3vw, 27px);
  line-height: 1.25;
  letter-spacing: -0.01em;
  font-weight: 750;
  margin-top: 42px;
  padding-top: 14px;
  border-top: 2px solid var(--line);
}
h3 {
  font-size: clamp(17px, 2.2vw, 20px);
  line-height: 1.3;
  font-weight: 700;
  margin-top: 28px;
}
h4 { font-size: 16px; font-weight: 700; margin-top: 22px; }

h2 .anchor, h3 .anchor {
  font-size: 0.7em;
  font-weight: 500;
  color: var(--ink-muted);
  text-decoration: none;
  margin-left: 8px;
  opacity: 0;
}
h2:hover .anchor, h3:hover .anchor, .anchor:focus-visible { opacity: 1; }

.lede {
  font-size: clamp(17px, 2.3vw, 19px);
  color: var(--ink-2);
  max-width: var(--measure);
}

.doc p, .doc li { max-width: var(--measure); }
.doc ul, .doc ol { padding-left: 22px; }
.doc li + li { margin-top: 6px; }
.doc ul { list-style: square; }

.small { font-size: 14px; color: var(--ink-muted); }

code, kbd, samp, pre { font-family: var(--font-mono); }
code {
  font-size: 0.9em;
  background: var(--surface-2);
  border: 1px solid var(--line);
  border-radius: 4px;
  padding: 0.08em 0.34em;
}
pre {
  background: var(--surface);
  border: 1px solid var(--line);
  border-left: 4px solid var(--indigo-line);
  border-radius: var(--radius);
  padding: 14px 16px;
  overflow-x: auto;
  font-size: 13.5px;
  line-height: 1.6;
}
pre code { background: none; border: 0; padding: 0; font-size: inherit; }
kbd {
  font-size: 0.85em;
  background: var(--surface-2);
  border: 1px solid var(--line-strong);
  border-bottom-width: 2px;
  border-radius: 4px;
  padding: 0.05em 0.4em;
}

/* ---------- hero ---------- */

.hero {
  background: var(--surface);
  border: 1px solid var(--line);
  border-top: 4px solid var(--indigo);
  border-radius: var(--radius);
  padding: 26px 22px;
}
.hero > * + * { margin-top: 14px; }

.stamp {
  display: flex;
  flex-wrap: wrap;
  gap: 6px 8px;
  list-style: none;
  font-size: 12.5px;
}
.stamp li {
  background: var(--surface-2);
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 3px 11px;
  color: var(--ink-2);
  max-width: none;
}
.stamp b { color: var(--ink); font-weight: 700; }

.cta { display: flex; flex-wrap: wrap; gap: 10px; }
.btn {
  display: inline-block;
  font-size: 15px;
  font-weight: 650;
  padding: 9px 16px;
  border-radius: var(--radius-sm);
  text-decoration: none;
  border: 1px solid var(--indigo);
}
.btn-solid { background: var(--indigo); color: var(--on-indigo); }
.btn-solid:hover { filter: brightness(1.08); }
.btn-line { background: transparent; color: var(--indigo); }
.btn-line:hover { background: var(--indigo-soft); }

/* ---------- panels ---------- */

.panel {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 18px 20px;
}
.panel > * + * { margin-top: 12px; }
.panel > h3:first-child, .panel > h2:first-child { margin-top: 0; border-top: 0; padding-top: 0; }

.cols {
  display: grid;
  gap: 16px;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
}
.cols > .panel { margin-top: 0; }

.note, .warn, .auth-note {
  border-radius: var(--radius);
  padding: 14px 16px;
  border: 1px solid var(--line);
  border-left-width: 4px;
  background: var(--surface-2);
}
.note { border-left-color: var(--indigo); }
.warn {
  border-left-color: var(--danger-line);
  background: var(--danger-soft);
  border-color: var(--danger-line);
}
.warn strong { color: var(--danger); }
.auth-note {
  border-left-color: var(--gold-line);
  background: var(--gold-soft);
  border-color: var(--gold-line);
}
.auth-note strong { color: var(--gold); }
.note > * + *, .warn > * + *, .auth-note > * + * { margin-top: 8px; }

/* ---------- authority language ---------- */

.tag {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  font-weight: 700;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  padding: 2px 8px;
  border-radius: 999px;
  border: 1px solid var(--indigo-line);
  background: var(--indigo-soft);
  color: var(--indigo);
  white-space: nowrap;
}
.tag-auth {
  border-color: var(--gold-line);
  background: var(--gold-soft);
  color: var(--gold);
}
.tag-out {
  border-color: var(--line-strong);
  background: var(--surface-2);
  color: var(--ink-muted);
}
.tag-ok { border-color: var(--ok-line); background: var(--ok-soft); color: var(--ok); }
.tag-no { border-color: var(--danger-line); background: var(--danger-soft); color: var(--danger); }

.op {
  border: 1px solid var(--line);
  border-left: 5px solid var(--indigo);
  border-radius: var(--radius);
  background: var(--surface);
  padding: 16px 18px;
}
.op[data-authority="required"] { border-left-color: var(--gold-line); }
.op[data-authority="required"] .op-head code { color: var(--gold); border-color: var(--gold-line); background: var(--gold-soft); }
.op > * + * { margin-top: 10px; }
.op-head {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px 10px;
}
.op-head h3 { margin: 0; font-size: 17px; }
.op-head code { font-size: 14px; font-weight: 700; }

.stack { display: grid; gap: 14px; }

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

.tablewrap {
  overflow-x: auto;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface);
}
table { border-collapse: collapse; width: 100%; font-size: 14.5px; }
caption {
  text-align: left;
  font-size: 13px;
  color: var(--ink-muted);
  padding: 10px 14px 0;
}
th, td {
  text-align: left;
  vertical-align: top;
  padding: 9px 14px;
  border-bottom: 1px solid var(--line);
}
thead th {
  background: var(--surface-2);
  font-size: 12px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--ink-2);
  white-space: nowrap;
}
tbody tr:last-child td { border-bottom: 0; }
tbody tr.is-auth { background: var(--gold-soft); }
tbody tr.is-auth td:first-child { box-shadow: inset 3px 0 0 var(--gold-line); }
td code { white-space: nowrap; }

/* ---------- numbered rules ---------- */

.rules { list-style: none; padding-left: 0; counter-reset: none; }
.rules > li {
  max-width: var(--measure);
  padding-left: 74px;
  position: relative;
  min-height: 26px;
}
.rules > li + li { margin-top: 12px; }
.rules > li > .rid {
  position: absolute;
  left: 0;
  top: 2px;
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 700;
  color: var(--indigo);
  background: var(--indigo-soft);
  border: 1px solid var(--indigo-line);
  border-radius: 4px;
  padding: 1px 6px;
}
.rules > li[data-authority="required"] > .rid {
  color: var(--gold);
  background: var(--gold-soft);
  border-color: var(--gold-line);
}

/* ---------- steps ---------- */

.steps { list-style: none; padding-left: 0; counter-reset: step; }
.steps > li {
  counter-increment: step;
  position: relative;
  padding-left: 46px;
  max-width: var(--measure);
}
.steps > li + li { margin-top: 20px; }
.steps > li::before {
  content: counter(step);
  position: absolute;
  left: 0;
  top: 0;
  width: 30px;
  height: 30px;
  display: grid;
  place-items: center;
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 14px;
  color: var(--on-indigo);
  background: var(--indigo);
  border-radius: 50%;
}
.steps > li[data-authority="required"]::before {
  color: var(--gold);
  background: var(--gold-soft);
  border: 2px solid var(--gold-line);
}
.steps h3 { margin-top: 0; }

/* ---------- vectors ---------- */

.vector {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface);
  overflow: hidden;
}
.vector + .vector { margin-top: 14px; }
.vector-head {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px 12px;
  padding: 12px 16px;
  background: var(--surface-2);
  border-bottom: 1px solid var(--line);
}
.vector-head h3 { margin: 0; font-size: 16px; }
.vector-body { padding: 14px 16px; }
.vector-body > * + * { margin-top: 10px; }
.vector-body pre { margin: 0; }
.vector[data-outcome="accepted"] { border-left: 5px solid var(--ok-line); }
.vector[data-outcome="rejected"] { border-left: 5px solid var(--danger-line); }

dl.kv { display: grid; grid-template-columns: max-content minmax(0, 1fr); gap: 4px 16px; font-size: 14.5px; }
dl.kv dt { font-weight: 700; color: var(--ink-2); }
dl.kv dd { margin: 0; min-width: 0; }

/* ---------- diagrams ---------- */

figure.fig {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 16px;
  overflow-x: auto;
}
figure.fig svg { display: block; min-width: 480px; width: 100%; height: auto; }
figure.fig figcaption {
  margin-top: 10px;
  font-size: 13.5px;
  color: var(--ink-muted);
  min-width: 0;
}
.d-plain { fill: var(--surface-2); stroke: var(--indigo-line); }
.d-auth { fill: var(--gold-soft); stroke: var(--gold-line); }
.d-line { stroke: var(--line-strong); fill: none; }
.d-flow { stroke: var(--indigo); fill: none; }
.d-flow-auth { stroke: var(--gold-line); fill: none; }
.d-text { fill: var(--ink); font-family: var(--font-text); font-size: 13px; }
.d-text-sm { fill: var(--ink-muted); font-family: var(--font-text); font-size: 11px; }
.d-code { fill: var(--ink); font-family: var(--font-mono); font-size: 12px; }
.d-arrow { fill: var(--indigo); }
.d-arrow-auth { fill: var(--gold-line); }

.legend { display: flex; flex-wrap: wrap; gap: 8px 16px; list-style: none; font-size: 13.5px; }
.legend li { display: flex; align-items: center; gap: 7px; max-width: none; }
.legend .sw { width: 15px; height: 15px; border-radius: 4px; border: 1px solid var(--indigo-line); background: var(--indigo-soft); flex: 0 0 auto; }
.legend .sw-auth { border-color: var(--gold-line); background: var(--gold-soft); }

/* ---------- validator ---------- */

.tool { display: grid; gap: 16px; }
@media (min-width: 900px) { .tool { grid-template-columns: minmax(0, 1fr) minmax(0, 1fr); } }
.tool label { display: block; font-weight: 700; margin-bottom: 6px; }
.tool textarea {
  font-family: var(--font-mono);
  font-size: 13.5px;
  line-height: 1.55;
  width: 100%;
  min-height: 240px;
  padding: 12px;
  color: var(--ink);
  background: var(--surface);
  border: 1px solid var(--line-strong);
  border-radius: var(--radius);
  resize: vertical;
}
.toolbar { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 10px; }
.toolbar button {
  font: inherit;
  font-size: 14px;
  font-weight: 650;
  padding: 7px 13px;
  border-radius: var(--radius-sm);
  cursor: pointer;
  background: var(--surface);
  color: var(--ink-2);
  border: 1px solid var(--line-strong);
}
.toolbar button:hover { border-color: var(--indigo); color: var(--indigo); }
.toolbar button.primary { background: var(--indigo); color: var(--on-indigo); border-color: var(--indigo); }
.toolbar button.primary:hover { filter: brightness(1.08); color: var(--on-indigo); }

.result { border: 1px solid var(--line); border-radius: var(--radius); background: var(--surface); padding: 16px; }
.result > * + * { margin-top: 12px; }
.result[data-state="ok"] { border-left: 5px solid var(--ok-line); }
.result[data-state="bad"] { border-left: 5px solid var(--danger-line); }
.result[data-state="info"] { border-left: 5px solid var(--indigo); }
.checks { list-style: none; padding-left: 0; font-size: 14.5px; }
.checks li { padding-left: 26px; position: relative; max-width: none; }
.checks li + li { margin-top: 5px; }
.checks li::before {
  position: absolute;
  left: 0;
  top: 0;
  font-family: var(--font-mono);
  font-weight: 700;
}
.checks li[data-r="pass"]::before { content: "OK"; color: var(--ok); font-size: 11px; top: 3px; }
.checks li[data-r="fail"]::before { content: "X"; color: var(--danger); }
.checks li[data-r="info"]::before { content: "i"; color: var(--indigo); }

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

.pagefoot {
  border-top: 2px solid var(--line);
  background: var(--bg-deep);
  padding: 26px 0 40px;
  font-size: 14px;
}
.pagefoot .shell > * + * { margin-top: 16px; }
.footgrid {
  display: grid;
  gap: 8px 28px;
  grid-template-columns: repeat(auto-fit, minmax(210px, 1fr));
}
.footgrid dl { display: grid; grid-template-columns: max-content minmax(0, 1fr); gap: 2px 12px; }
.footgrid dt { color: var(--ink-muted); }
.footgrid dd { margin: 0; color: var(--ink); min-width: 0; }
.footlinks { display: flex; flex-wrap: wrap; gap: 6px 18px; list-style: none; }
.footnote { color: var(--ink-muted); max-width: var(--measure); }

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

.vh {
  position: absolute;
  width: 1px;
  height: 1px;
  margin: -1px;
  padding: 0;
  overflow: hidden;
  clip: rect(0 0 0 0);
  clip-path: inset(50%);
  white-space: nowrap;
  border: 0;
}

html:not(.js) .jsonly { display: none; }
html.js .nojs { display: none; }

.linklist { list-style: none; padding-left: 0; display: grid; gap: 8px; }
.linklist li { max-width: var(--measure); }
.linklist a { font-weight: 650; }
.linklist span { display: block; font-size: 14px; color: var(--ink-muted); }

@media (prefers-reduced-motion: reduce) {
  * { animation: none !important; transition: none !important; scroll-behavior: auto !important; }
}