/* BusScope — the page is a page from an interface specification: a figure,
   a caption, and the text that explains what the figure is showing. Colour
   carries one meaning only, which is who is driving the wire. */

:root {
  --paper:      #f3f4f1;
  --figure:     #ffffff;
  --band:       #eaece7;
  --rule:       #d2d5d1;
  --ink:        #14181c;
  --ink-2:      #4c545a;
  --ink-3:      #79818a;

  --man:        #1a4fd0;   /* manager / controller / source */
  --sub:        #ad2a72;   /* subordinate / target / sink   */
  --event:      #0d7a52;   /* the edge that captures        */
  --idle:       #9aa3a9;
  --cursor:     rgba(26, 79, 208, 0.07);
  --clock:      #5a636a;

  --sans: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --mono: ui-monospace, "SF Mono", "JetBrains Mono", "Cascadia Mono", Menlo, Consolas, monospace;
}

[data-theme="dark"] {
  --paper:      #14171a;
  --figure:     #0e1113;
  --band:       #1b2023;
  --rule:       #2b3237;
  --ink:        #e6eae8;
  --ink-2:      #a3abaf;
  --ink-3:      #7b848a;
  --man:        #74a2ff;
  --sub:        #f083bd;
  --event:      #4fca90;
  --idle:       #6b747a;
  --cursor:     rgba(116, 162, 255, 0.10);
  --clock:      #8d979d;
}

* { box-sizing: border-box; }
@media (prefers-reduced-motion: reduce) { * { transition: none !important; animation: none !important; } }

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 15px;
  line-height: 1.55;
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3 { font-weight: 620; letter-spacing: -0.015em; margin: 0; }
p { margin: 0; }
code, kbd { font-family: var(--mono); font-size: 0.92em; }
:focus-visible { outline: 2px solid var(--man); outline-offset: 2px; }

/* ---------- rail ---------- */

.rail {
  position: sticky; top: 0; z-index: 20;
  display: flex; align-items: center; gap: 22px;
  height: 52px; padding: 0 22px;
  background: var(--paper);
  border-bottom: 1px solid var(--rule);
}
.wordmark { font-size: 17px; letter-spacing: -0.03em; }
.views { display: flex; gap: 2px; }
.viewtab {
  border: 0; background: none; font: inherit; font-size: 13.5px; cursor: pointer;
  color: var(--ink-3); padding: 6px 11px;
}
.viewtab:hover { color: var(--ink); }
.viewtab.is-on { color: var(--ink); box-shadow: inset 0 -2px 0 var(--ink); }
.rail-actions { margin-left: auto; display: flex; gap: 7px; }

.chip {
  font: inherit; font-size: 12.5px; cursor: pointer;
  color: var(--ink-2); background: none;
  border: 1px solid var(--rule); border-radius: 3px; padding: 5px 10px;
}
.chip:hover { color: var(--ink); border-color: var(--ink-3); }

main { max-width: 1480px; margin: 0 auto; padding: 22px 22px 56px; }
.view { display: none; }
.view.is-on { display: block; }

/* ---------- protocol index ---------- */

.explore { display: grid; grid-template-columns: 178px minmax(0, 1fr); gap: 34px; align-items: start; }

.index { position: sticky; top: 74px; }
.index h4 {
  margin: 18px 0 6px; font-size: 11.5px; font-weight: 620; color: var(--ink-3);
  letter-spacing: 0.01em;
}
.index h4:first-child { margin-top: 0; }
.index button {
  display: block; width: 100%; text-align: left;
  border: 0; border-left: 2px solid transparent; background: none;
  font: inherit; font-size: 13.5px; color: var(--ink-2);
  padding: 4px 0 4px 10px; cursor: pointer;
}
.index button:hover { color: var(--ink); }
.index button.is-on { color: var(--ink); font-weight: 620; border-left-color: var(--man); }
.index button small { display: block; font-size: 11px; color: var(--ink-3); font-weight: 400; }

/* ---------- stage ---------- */

.stage { min-width: 0; }
.stage-head { max-width: 76ch; }
.stage-head h2 { font-size: 27px; letter-spacing: -0.025em; }
.stage-kind { font-size: 12.5px; color: var(--ink-3); margin-top: 2px; }
.stage-summary { color: var(--ink-2); margin-top: 10px; font-size: 14.5px; }

/* ---------- toolbar ---------- */

.toolbar {
  display: flex; flex-wrap: wrap; align-items: end; gap: 18px;
  margin: 22px 0 14px; padding: 12px 0;
  border-top: 1px solid var(--rule); border-bottom: 1px solid var(--rule);
}
.tool { display: grid; gap: 4px; }
.tool > span { font-size: 11.5px; color: var(--ink-3); }
.tool output { font-family: var(--mono); color: var(--ink); }
.tool select {
  font: inherit; font-size: 13px; color: var(--ink);
  background: var(--figure); border: 1px solid var(--rule); border-radius: 3px; padding: 5px 7px;
}
.tool-range input { width: 132px; accent-color: var(--man); }
.tool-check { display: flex; align-items: center; gap: 7px; font-size: 13px; color: var(--ink-2); padding-bottom: 4px; }
.tool-check input { accent-color: var(--man); width: 15px; height: 15px; }

.transport { margin-left: auto; display: flex; gap: 6px; }
.transport button {
  font: inherit; font-size: 13px; cursor: pointer; min-width: 36px; padding: 6px 10px;
  color: var(--ink-2); background: var(--figure);
  border: 1px solid var(--rule); border-radius: 3px;
}
.transport button:hover { color: var(--ink); border-color: var(--ink-3); }
.transport .is-primary { color: var(--figure); background: var(--ink); border-color: var(--ink); min-width: 68px; }

/* ---------- figure ---------- */

.figure { margin: 0; }
.scroller {
  overflow-x: auto; overflow-y: hidden;
  background: var(--figure);
  border: 1px solid var(--rule);
  border-radius: 2px;
}
.scroller canvas { display: block; cursor: crosshair; }
.figure figcaption {
  display: flex; gap: 9px; align-items: baseline;
  margin-top: 9px; font-size: 13px; color: var(--ink-2); max-width: 88ch;
}
.fig-no { font-size: 11.5px; font-weight: 640; color: var(--ink-3); flex: none; }

.legend { display: flex; flex-wrap: wrap; gap: 8px 22px; margin-top: 12px; font-size: 12px; color: var(--ink-3); }
.legend span { display: flex; align-items: center; gap: 7px; }
.sw { width: 14px; height: 3px; display: inline-block; }
.sw-man { background: var(--man); }
.sw-sub { background: var(--sub); }
.sw-event { background: var(--event); }
.sw-idle { background: var(--idle); }

/* ---------- cycle inspector ---------- */

.inspector { margin-top: 30px; padding-top: 16px; border-top: 1px solid var(--rule); }
.inspector-head { display: flex; align-items: baseline; gap: 12px; }
.inspector-head h3 { font-size: 16px; }
.cycle-phase { font-family: var(--mono); font-size: 12px; color: var(--man); }
.cycle-note { margin-top: 7px; color: var(--ink-2); font-size: 14px; max-width: 78ch; }

.values { border-collapse: collapse; margin-top: 16px; width: 100%; max-width: 620px; }
.values th, .values td { text-align: left; padding: 6px 14px 6px 0; border-bottom: 1px solid var(--rule); }
.values th { font-size: 11.5px; font-weight: 620; color: var(--ink-3); }
.values td { font-family: var(--mono); font-size: 12.5px; }
.values td:first-child { color: var(--ink-2); }
.values td.v-man { color: var(--man); }
.values td.v-sub { color: var(--sub); }
.values td.v-idle { color: var(--idle); }
.values td:last-child { font-family: var(--sans); font-size: 12px; color: var(--ink-3); }

/* ---------- where it fits ---------- */

.fit { margin-top: 34px; }
.fit h3 { font-size: 16px; margin-bottom: 10px; }
.fit dl { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 0 46px; margin: 0; }
.fit dl > div { padding: 13px 0; border-top: 1px solid var(--rule); }
.fit dt { font-size: 14px; font-weight: 620; }
.fit dt small { display: block; font-weight: 400; font-size: 11.5px; color: var(--ink-3); }
.fit dd { margin: 4px 0 0; color: var(--ink-2); font-size: 13.5px; max-width: 54ch; }

/* ---------- compare ---------- */

.head { max-width: 74ch; margin-bottom: 18px; }
.head h2 { font-size: 24px; }
.head p { color: var(--ink-2); margin-top: 6px; font-size: 14.5px; }

.picker { display: flex; flex-wrap: wrap; gap: 7px; margin-bottom: 16px; }
.picker button {
  font: inherit; font-size: 12.5px; cursor: pointer; padding: 5px 12px;
  color: var(--ink-3); background: none; border: 1px solid var(--rule); border-radius: 999px;
}
.picker button.is-on { color: var(--figure); background: var(--ink); border-color: var(--ink); }

.matrix-wrap { overflow-x: auto; }
.matrix { border-collapse: collapse; width: 100%; min-width: 720px; }
.matrix th, .matrix td {
  text-align: left; vertical-align: top; padding: 11px 16px 11px 0;
  border-bottom: 1px solid var(--rule); font-size: 13px;
}
.matrix thead th { font-size: 13.5px; font-weight: 640; border-bottom: 1.5px solid var(--ink); }
.matrix tbody th { font-weight: 400; color: var(--ink-3); width: 190px; font-size: 12.5px; }
.matrix td { color: var(--ink-2); }

.notes { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 0 46px; margin-top: 8px; }
.notes > article { padding: 15px 0; border-bottom: 1px solid var(--rule); }
.notes h3 { font-size: 14px; }
.notes p { color: var(--ink-2); font-size: 13.5px; margin-top: 4px; max-width: 56ch; }

/* ---------- reference ---------- */

.ref { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 0 46px; margin: 0; }
.ref > div { padding: 15px 0; border-top: 1px solid var(--rule); }
.ref dt { font-weight: 620; font-size: 14.5px; }
.ref dd { margin: 5px 0 0; color: var(--ink-2); font-size: 14px; max-width: 58ch; }

.axi-fields { margin-top: 36px; }
.axi-fields h3 { font-size: 16px; margin-bottom: 8px; }
.axi-fields dl { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 0 34px; margin: 0; }
.axi-fields dl > div { padding: 13px 0; border-top: 1px solid var(--rule); }
.axi-fields dt { font-family: var(--mono); font-size: 12.5px; color: var(--man); }
.axi-fields dd { margin: 5px 0 0; color: var(--ink-2); font-size: 13.5px; }
.ref-note { margin-top: 14px; color: var(--ink-3); font-size: 13px; max-width: 70ch; }

.keys-block { margin-top: 36px; padding-top: 16px; border-top: 1px solid var(--rule); }
.keys-block h3 { font-size: 15px; margin-bottom: 10px; }
.keylist { list-style: none; padding: 0; margin: 0; display: flex; flex-wrap: wrap; gap: 8px 26px; }
.keylist li { display: flex; align-items: center; gap: 7px; font-size: 13px; color: var(--ink-2); }
kbd { border: 1px solid var(--rule); border-bottom-width: 2px; border-radius: 3px; padding: 1px 6px; font-size: 11.5px; }

.colophon { border-top: 1px solid var(--rule); padding: 16px 22px 40px; color: var(--ink-3); font-size: 12.5px; }
.colophon p { max-width: 1480px; margin: 0 auto; }

/* ---------- responsive ---------- */

@media (max-width: 1000px) {
  .explore { grid-template-columns: 1fr; gap: 20px; }
  .index { position: static; display: flex; flex-wrap: wrap; gap: 4px 14px; align-items: baseline;
    padding-bottom: 12px; border-bottom: 1px solid var(--rule); }
  .index h4 { margin: 0; width: 100%; }
  .index button { width: auto; border-left: 0; border-bottom: 2px solid transparent; padding: 3px 0; }
  .index button small { display: none; }
  .index button.is-on { border-left-color: transparent; border-bottom-color: var(--man); }
  .fit dl, .notes, .ref { grid-template-columns: 1fr; }
  .axi-fields dl { grid-template-columns: 1fr; }
}
@media (max-width: 700px) {
  .rail { height: auto; padding: 8px 12px; flex-wrap: wrap; gap: 10px; position: static; }
  main { padding: 14px 12px 40px; }
  .toolbar { gap: 14px; }
  .transport { margin-left: 0; }
  .stage-head h2 { font-size: 22px; }
}