/* AAD — engineering spec sheet. Dark by default, light on request or by preference. */

:root {
  --bg: #0c0e0f;
  --bg-2: #121516;
  --bg-3: #181c1e;
  --line: #24292c;
  --line-2: #323a3e;
  --fg: #dfe3e1;
  --fg-2: #a3aba8;
  --muted: #6f7875;
  --accent: #c6f26a;
  --accent-ink: #0c0e0f;
  --ok: #7bd88f;
  --warn: #f2b84b;
  --warn-line: #f2b84b;
  --info: #7aa7ff;
  --bad: #ff6b6b;
  --chevron: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='10' height='6' viewBox='0 0 10 6'%3E%3Cpath d='M1 1l4 4 4-4' fill='none' stroke='%23a3aba8' stroke-width='1.5' stroke-linecap='round' stroke-linejoin='round'/%3E%3C/svg%3E");
  --mono: ui-monospace, "SF Mono", "JetBrains Mono", "Cascadia Code", Menlo, Consolas, monospace;
  --sans: ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  --gutter: 24px;
  --max: 1160px;
  color-scheme: dark;
}

@media (prefers-color-scheme: light) {
  :root:not([data-theme="dark"]) {
    --bg: #f5f4ef;
    --bg-2: #ecebe4;
    --bg-3: #e3e2da;
    --line: #d4d2c8;
    --line-2: #bfbdb2;
    --fg: #15181a;
    --fg-2: #3d4447;
    --muted: #6d7275;
    --accent: #3f6d00;
    --accent-ink: #f5f4ef;
    --ok: #1f7a35;
    --warn: #9a5b00;
    --warn-line: #d9952b;
    --info: #2453c4;
    --bad: #c42b2b;
    --chevron: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='10' height='6' viewBox='0 0 10 6'%3E%3Cpath d='M1 1l4 4 4-4' fill='none' stroke='%233d4447' stroke-width='1.5' stroke-linecap='round' stroke-linejoin='round'/%3E%3C/svg%3E");
    color-scheme: light;
  }
}

:root[data-theme="light"] {
  --bg: #f5f4ef;
  --bg-2: #ecebe4;
  --bg-3: #e3e2da;
  --line: #d4d2c8;
  --line-2: #bfbdb2;
  --fg: #15181a;
  --fg-2: #3d4447;
  --muted: #6d7275;
  --accent: #3f6d00;
  --accent-ink: #f5f4ef;
  --ok: #1f7a35;
  --warn: #9a5b00;
  --warn-line: #d9952b;
  --info: #2453c4;
  --bad: #c42b2b;
  --chevron: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='10' height='6' viewBox='0 0 10 6'%3E%3Cpath d='M1 1l4 4 4-4' fill='none' stroke='%233d4447' stroke-width='1.5' stroke-linecap='round' stroke-linejoin='round'/%3E%3C/svg%3E");
  color-scheme: light;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: 64px;
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font: 15px / 1.6 var(--sans);
  -webkit-font-smoothing: antialiased;
}

a {
  color: inherit;
  text-decoration-color: var(--line-2);
  text-underline-offset: 3px;
}

a:hover {
  color: var(--accent);
  text-decoration-color: currentColor;
}

code,
pre,
kbd,
textarea,
input,
select,
button {
  font-family: var(--mono);
}

code {
  font-size: 0.88em;
  background: var(--bg-3);
  border: 1px solid var(--line);
  border-radius: 3px;
  padding: 0 0.3em;
}

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

h1,
h2,
h3 {
  font-family: var(--mono);
  letter-spacing: -0.02em;
  margin: 0;
}

.label {
  font: 500 11px / 1.4 var(--mono);
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--muted);
  margin: 0;
}

.muted {
  color: var(--muted);
}

/* ── top bar ─────────────────────────────────────────────────────────────── */

.bar {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  gap: 24px;
  padding: 10px var(--gutter);
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--line);
  font: 13px var(--mono);
}

.mark {
  display: flex;
  align-items: center;
  gap: 8px;
  text-decoration: none;
}

.mark-box {
  font-weight: 700;
  border: 1.5px solid var(--accent);
  color: var(--accent);
  padding: 1px 6px;
  border-radius: 3px;
}

.mark-ver {
  color: var(--muted);
}

.bar nav {
  display: flex;
  gap: 16px;
  overflow-x: auto;
  scrollbar-width: none;
  flex: 1;
}

.bar nav a,
.bar-end a {
  color: var(--fg-2);
  text-decoration: none;
  white-space: nowrap;
}

.bar nav a:hover,
.bar-end a:hover {
  color: var(--accent);
}

.bar-end {
  display: flex;
  align-items: center;
  gap: 16px;
}

.ext::after {
  content: " ↗";
  color: var(--muted);
}

.theme {
  display: grid;
  place-items: center;
  width: 28px;
  height: 28px;
  padding: 0;
  background: none;
  border: 1px solid transparent;
  border-radius: 4px;
  color: var(--fg-2);
  cursor: pointer;
  transition:
    color 0.15s,
    border-color 0.15s;
}

.theme:hover {
  color: var(--accent);
  border-color: var(--line-2);
}

.theme svg {
  width: 16px;
  height: 16px;
  fill: none;
  stroke: currentColor;
  stroke-width: 1.6;
  stroke-linecap: round;
  stroke-linejoin: round;
}

/* Show the theme the button switches to: moon in light mode, sun in dark mode. */
.theme .sun {
  display: none;
}

:root[data-theme="dark"] .theme .sun {
  display: block;
}

:root[data-theme="dark"] .theme .moon {
  display: none;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) .theme .sun {
    display: block;
  }
  :root:not([data-theme="light"]) .theme .moon {
    display: none;
  }
}

/* ── layout ──────────────────────────────────────────────────────────────── */

main {
  max-width: var(--max);
  margin: 0 auto;
  padding: 0 var(--gutter);
}

.hero {
  padding: 88px 0 56px;
  border-bottom: 1px solid var(--line);
  background: radial-gradient(var(--line-2) 1px, transparent 1.5px) 0 0 / 24px 24px;
  mask-image: linear-gradient(#000, #000);
  position: relative;
}

.hero > * {
  position: relative;
}

.hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(
    100deg,
    var(--bg) 35%,
    color-mix(in srgb, var(--bg) 55%, transparent)
  );
}

.eyebrow {
  font: 12px var(--mono);
  color: var(--accent);
  letter-spacing: 0.06em;
  text-transform: uppercase;
  margin: 0 0 20px;
}

.hero h1 {
  font-size: clamp(40px, 7.5vw, 84px);
  line-height: 0.98;
  letter-spacing: -0.045em;
  font-weight: 700;
}

.lede {
  max-width: 62ch;
  font-size: 18px;
  color: var(--fg-2);
  margin: 28px 0 32px;
}

.lede strong,
.lede em {
  color: var(--fg);
}

.term {
  max-width: 760px;
  border: 1px solid var(--line-2);
  border-radius: 4px;
  background: var(--bg-2);
}

.term-head {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 6px 12px;
  border-bottom: 1px solid var(--line);
  font: 11px var(--mono);
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

.term pre {
  margin: 0;
  padding: 14px 16px;
  overflow-x: auto;
  font-size: 13px;
  line-height: 1.7;
}

.term pre code {
  background: none;
  border: 0;
  padding: 0;
}

.term pre code::before {
  content: "$ ";
  color: var(--accent);
}

.term + .term {
  margin-top: 12px;
}

.term.prompt pre {
  max-height: 22em;
  white-space: pre-wrap;
}

.term.prompt pre code::before {
  content: none;
}

.copy,
.ghost {
  background: none;
  border: 1px solid var(--line-2);
  color: var(--fg-2);
  font-size: 11px;
  padding: 3px 10px;
  border-radius: 3px;
  cursor: pointer;
}

.copy:hover,
.ghost:hover {
  border-color: var(--accent);
  color: var(--accent);
}

.facts {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  margin: 40px 0 0;
  border-top: 1px solid var(--line);
}

.facts div {
  padding: 14px 16px 0 0;
}

.facts div + div {
  padding-left: 16px;
  border-left: 1px solid var(--line);
}

.facts dt {
  font: 11px var(--mono);
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

.facts dd {
  margin: 4px 0 0;
  font: 14px var(--mono);
}

.sec {
  padding: 72px 0;
  border-bottom: 1px solid var(--line);
}

.sec-head {
  display: grid;
  grid-template-columns: 80px 1fr;
  column-gap: 16px;
  margin-bottom: 32px;
}

.sec-no {
  grid-row: span 2;
  font: 13px var(--mono);
  color: var(--accent);
  padding-top: 8px;
}

.sec-head h2 {
  font-size: 30px;
}

.sec-head p {
  margin: 8px 0 0;
  color: var(--fg-2);
  max-width: 70ch;
}

.split {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  gap: 24px;
  align-items: start;
}

.panel {
  border: 1px solid var(--line);
  background: var(--bg-2);
  border-radius: 4px;
  padding: 20px;
}

.panel h3 {
  font-size: 16px;
  margin-bottom: 12px;
}

.panel p {
  margin: 0 0 12px;
}

/* ── tags ────────────────────────────────────────────────────────────────── */

.tag,
.tag-sm {
  display: inline-block;
  font: 600 11px / 1 var(--mono);
  letter-spacing: 0.04em;
  text-transform: uppercase;
  padding: 5px 8px;
  border-radius: 3px;
  border: 1px solid currentColor;
}

.tag-sm {
  font-size: 10px;
  padding: 3px 6px;
  color: var(--muted);
}

.routine {
  --c: var(--ok);
}
.approval-sensitive {
  --c: var(--warn);
}
.unclassified {
  --c: var(--info);
}
.invalid {
  --c: var(--bad);
}

.tag.routine,
.tag.approval-sensitive,
.tag.unclassified,
.tag.invalid {
  color: var(--c);
  background: color-mix(in srgb, var(--c) 10%, transparent);
}

.dot {
  display: inline-block;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--c);
  flex: none;
}

.legend {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 16px;
}

/* ── §01 rules ───────────────────────────────────────────────────────────── */

.rules {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  border-top: 1px solid var(--line);
  border-left: 1px solid var(--line);
}

.rules li {
  display: flex;
  gap: 12px;
  padding: 18px;
  border-right: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  min-height: 96px;
  transition: background 0.15s;
}

.rules li:hover {
  background: var(--bg-2);
}

.rules .n,
.steps li::before,
.checklist .n,
.tabs .n,
.log .n {
  font: 12px var(--mono);
  color: var(--accent);
}

.sub {
  font-size: 18px;
  margin: 48px 0 4px;
}

.sub-note {
  margin: 0 0 16px;
}

.table-wrap {
  overflow-x: auto;
  border: 1px solid var(--line);
  border-radius: 4px;
}

.ref {
  width: 100%;
  border-collapse: collapse;
  font-size: 14px;
}

.ref th {
  text-align: left;
  font: 500 11px var(--mono);
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--muted);
  background: var(--bg-2);
}

.ref th,
.ref td {
  padding: 10px 14px;
  border-bottom: 1px solid var(--line);
  vertical-align: top;
}

.ref tr:last-child td {
  border-bottom: 0;
}

.ref td {
  color: var(--fg-2);
}

.ref td:first-child {
  font-family: var(--mono);
  font-size: 13px;
  color: var(--fg);
}

@media (max-width: 640px) {
  .ref,
  .ref tbody,
  .ref tr,
  .ref td {
    display: block;
  }
  .ref thead {
    display: none;
  }
  .ref td {
    border: 0;
    padding: 2px 14px;
  }
  .ref td:first-child {
    padding-top: 12px;
  }
  .ref tr {
    border-bottom: 1px solid var(--line);
    padding-bottom: 12px;
  }
}

/* ── §02 tree ────────────────────────────────────────────────────────────── */

.tree {
  list-style: none;
  margin: 0;
  padding: 12px 0;
  border: 1px solid var(--line);
  border-radius: 4px;
  background: var(--bg-2);
  font: 13px var(--mono);
}

.tree button {
  all: unset;
  display: flex;
  align-items: stretch;
  width: 100%;
  box-sizing: border-box;
  height: 26px;
  padding: 0 16px;
  cursor: pointer;
  color: var(--fg-2);
  white-space: nowrap;
}

.tree .name,
.tree .muted {
  align-self: center;
  overflow: hidden;
  text-overflow: ellipsis;
}

.tree .muted {
  margin-left: 0.6ch;
  overflow: visible;
}

/* Tree guides: each segment is one indent column; lines touch across rows. */
.guide {
  position: relative;
  flex: none;
  width: 22px;
  color: var(--muted);
}

.guide::before,
.guide::after {
  content: "";
  position: absolute;
  left: 7px;
  border-color: currentColor;
  border-style: solid;
  border-width: 0;
}

.guide.pipe::before,
.guide.tee::before {
  top: 0;
  bottom: 0;
  border-left-width: 1px;
}

.guide.elbow::before {
  top: 0;
  height: 50%;
  border-left-width: 1px;
}

.guide.tee::after,
.guide.elbow::after {
  top: 50%;
  width: 10px;
  border-top-width: 1px;
}

.tree button:hover {
  color: var(--fg);
  background: var(--bg-3);
}

.tree button:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: -2px;
}

.tree button[aria-pressed="true"] {
  color: var(--accent-ink);
  background: var(--accent);
}

.tree button[aria-pressed="true"] .guide,
.tree button[aria-pressed="true"] .muted {
  color: inherit;
}

[data-tree-detail] {
  position: sticky;
  top: 72px;
}

[data-tree-detail] h3 {
  font-size: 22px;
  margin: 4px 0 14px;
}

[data-tree-detail] .sample {
  margin: 6px 0 0;
  padding: 12px 14px;
  background: var(--bg);
  border: 1px solid var(--line);
  border-radius: 3px;
  font-size: 12px;
  line-height: 1.6;
  white-space: pre-wrap;
  overflow-wrap: anywhere;
  max-height: 360px;
  overflow-y: auto;
}

[data-tree-detail] .tree-sample {
  font-family: var(--mono);
  white-space: nowrap;
  overflow-x: auto;
  line-height: 1;
}

.tree-sample .line {
  display: flex;
  align-items: stretch;
  height: 20px;
}

.tree-sample .guide {
  width: 20px;
}

.tree-sample .name,
.tree-sample .comment {
  align-self: center;
}

.tree-sample .comment {
  margin-left: 2ch;
  color: var(--muted);
}

[data-tree-detail] .sample code,
[data-tree-detail] h3 code {
  background: none;
  border: 0;
  padding: 0;
}

/* ── §03 machine ─────────────────────────────────────────────────────────── */

.machine {
  border: 1px solid var(--line);
  border-radius: 4px;
  background: var(--bg-2);
}

[data-machine] {
  display: block;
  width: 100%;
  height: auto;
  border-bottom: 1px solid var(--line);
  font: 13px var(--mono);
}

/* Lines use a lighter amber than text; labels keep --warn for contrast. */
.edge.approval-sensitive {
  --c-line: var(--warn-line);
}

.edge path {
  fill: none;
  stroke: var(--c-line, var(--c));
  stroke-width: 1.5;
  opacity: 0.28;
  transition:
    opacity 0.2s,
    stroke-width 0.2s;
}

.edge text {
  fill: var(--c);
  font-size: 10px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  opacity: 0.35;
}

.edge.live path {
  opacity: 1;
  stroke-width: 2;
  stroke-dasharray: 5 4;
  animation: flow 0.8s linear infinite;
}

.edge.live text {
  opacity: 1;
}

@keyframes flow {
  to {
    stroke-dashoffset: -9;
  }
}

@media (prefers-reduced-motion: reduce) {
  .edge.live path {
    animation: none;
  }
}

.arrow.routine {
  fill: var(--ok);
}

.arrow.approval-sensitive {
  fill: var(--warn-line);
}

.node {
  cursor: pointer;
}

.node rect {
  fill: var(--bg);
  stroke: var(--line-2);
  stroke-width: 1.5;
  transition:
    fill 0.15s,
    stroke 0.15s;
}

.node text {
  fill: var(--fg);
}

.node:hover rect,
.node:focus-visible rect {
  stroke: var(--accent);
}

.node:focus {
  outline: none;
}

.node.on rect {
  fill: var(--accent);
  stroke: var(--accent);
}

.node.on text {
  fill: var(--accent-ink);
  font-weight: 700;
}

.machine-ctl {
  padding: 16px 20px 20px;
}

.row {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 12px 16px;
}

.pill {
  font: 600 13px var(--mono);
  color: var(--accent);
}

.check {
  display: flex;
  align-items: center;
  gap: 8px;
  cursor: pointer;
  font-size: 14px;
}

.check input {
  accent-color: var(--accent);
  margin: 0;
  width: 15px;
  height: 15px;
  flex: none;
}

.targets {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 16px 0;
}

.target {
  display: flex;
  align-items: center;
  gap: 10px;
  background: var(--bg);
  border: 1px solid var(--line-2);
  border-left: 3px solid var(--c);
  color: var(--fg);
  font-size: 13px;
  padding: 8px 12px;
  border-radius: 3px;
  cursor: pointer;
}

.target:hover {
  border-color: var(--c);
}

.target .tag-sm {
  color: var(--c);
}

.log {
  list-style: none;
  margin: 0;
  padding: 12px 14px;
  background: var(--bg);
  border: 1px solid var(--line);
  border-radius: 3px;
  font: 12px / 1.8 var(--mono);
  min-height: 120px;
  overflow-x: auto;
}

.log li {
  white-space: pre-wrap;
  overflow-wrap: anywhere;
  padding-left: 2.2em;
  text-indent: -2.2em;
  color: var(--fg-2);
}

.log li .n {
  margin-right: 12px;
  color: var(--muted);
}

.log li.routine {
  color: var(--ok);
}
.log li.approval-sensitive {
  color: var(--warn);
}
.log li.invalid {
  color: var(--bad);
}

.log li:first-child {
  animation: in 0.25s ease-out;
}

@keyframes in {
  from {
    opacity: 0;
    transform: translateY(-3px);
  }
}

/* ── §04 lint ────────────────────────────────────────────────────────────── */

.lint {
  display: grid;
  grid-template-columns: minmax(0, 1.1fr) minmax(0, 1fr);
  grid-template-rows: auto 1fr;
  border: 1px solid var(--line);
  border-radius: 4px;
  overflow: hidden;
}

/* Both panels share the parent's rows, so their headers always match in height. */
.editor,
.output {
  display: grid;
  grid-row: span 2;
  grid-template-rows: subgrid;
}

.editor {
  border-right: 1px solid var(--line);
}

.editor-head,
.output-head {
  display: flex;
  flex-wrap: wrap;
  align-items: end;
  gap: 12px;
  padding: 10px 14px;
  background: var(--bg-2);
  border-bottom: 1px solid var(--line);
}

.output-head {
  justify-content: space-between;
  align-items: center;
  font: 12px var(--mono);
}

.editor-head label,
.form label:not(.check) {
  display: grid;
  gap: 4px;
}

input[type="text"],
input[type="search"],
select {
  background: var(--bg);
  color: var(--fg);
  border: 1px solid var(--line-2);
  border-radius: 3px;
  padding: 0 8px;
  height: 30px;
  font-size: 13px;
  min-width: 0;
}

select {
  appearance: none;
  /* Chevron sits 8px from the right edge, matching the 8px left padding. */
  padding-right: 26px;
  background: var(--bg) var(--chevron) no-repeat right 8px center / 10px 6px;
  cursor: pointer;
}

.editor-head input {
  width: 120px;
}

.editor-head .ghost {
  height: 30px;
}

textarea {
  resize: vertical;
  min-height: 420px;
  background: var(--bg);
  color: var(--fg);
  border: 0;
  padding: 14px 16px;
  font-size: 13px;
  line-height: 1.65;
  tab-size: 2;
}

textarea:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: -2px;
}

.output {
  background: var(--bg);
}

.good {
  color: var(--ok);
}
.warn {
  color: var(--warn);
}
.bad {
  color: var(--bad);
}

.diag {
  list-style: none;
  margin: 0;
  padding: 8px 0;
  font: 12px / 1.55 var(--mono);
}

.diag li {
  display: grid;
  grid-template-columns: auto auto 1fr;
  gap: 2px 10px;
  padding: 8px 14px;
  border-bottom: 1px dashed var(--line);
}

.diag .loc {
  color: var(--muted);
}

.diag .sev {
  font-weight: 700;
  text-transform: uppercase;
}

.diag .msg {
  color: var(--fg);
  font-family: var(--sans);
  font-size: 13px;
}

.diag .rule {
  grid-column: 3;
  color: var(--muted);
}

.diag .error .sev {
  color: var(--bad);
}
.diag .warning .sev {
  color: var(--warn);
}
.diag .info .sev {
  color: var(--info);
}
.diag .ok .msg {
  grid-column: 1 / -1;
  color: var(--ok);
}

/* ── §05 publication ─────────────────────────────────────────────────────── */

.changes fieldset {
  border: 0;
  margin: 0 0 18px;
  padding: 0;
}

.changes legend {
  margin-bottom: 6px;
}

.change {
  justify-content: space-between;
  padding: 7px 10px;
  border: 1px solid var(--line);
  border-radius: 3px;
  margin-bottom: 4px;
  background: var(--bg-2);
}

.change span:nth-child(2) {
  flex: 1;
}

.change:has(input:checked) {
  border-color: var(--c, var(--line-2));
  background: var(--bg-3);
}

.change:has(.routine) {
  --c: var(--ok);
}
.change:has(.approval-sensitive) {
  --c: var(--warn);
}
.change:has(.unclassified) {
  --c: var(--info);
}
.change:has(.invalid) {
  --c: var(--bad);
}

.presets {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 6px;
}

.verdict {
  position: sticky;
  top: 72px;
}

.verdict .path {
  font-size: 16px;
  margin: 12px 0 20px;
}

.verdict ul {
  margin: 6px 0 18px;
  padding-left: 18px;
  color: var(--fg-2);
  font-size: 14px;
}

.verdict .notes {
  list-style: none;
  padding: 0;
}

.verdict .notes li {
  display: flex;
  gap: 10px;
  align-items: baseline;
  margin-bottom: 6px;
}

/* ── §06 activities ──────────────────────────────────────────────────────── */

.tabs {
  display: flex;
  overflow-x: auto;
  border-bottom: 1px solid var(--line);
  scrollbar-width: thin;
}

.tabs button {
  background: none;
  border: 0;
  border-bottom: 2px solid transparent;
  color: var(--fg-2);
  font-size: 13px;
  padding: 10px 16px;
  cursor: pointer;
  white-space: nowrap;
  display: flex;
  gap: 8px;
}

.tabs button[aria-selected="true"] {
  color: var(--fg);
  border-bottom-color: var(--accent);
}

.tab-body {
  padding: 28px 0 0;
  max-width: 780px;
}

.lede-sm {
  font-size: 18px;
  margin: 0 0 20px;
}

.steps {
  list-style: none;
  counter-reset: step;
  margin: 0;
  padding: 0;
}

.steps li {
  counter-increment: step;
  display: grid;
  grid-template-columns: 36px 1fr;
  padding: 9px 0;
  border-bottom: 1px solid var(--line);
}

.steps li::before {
  content: counter(step, decimal-leading-zero);
  padding-top: 2px;
}

.note {
  margin-top: 20px;
  padding: 12px 16px;
  border-left: 2px solid var(--accent);
  background: var(--bg-2);
  color: var(--fg-2);
}

/* ── §07 startup ─────────────────────────────────────────────────────────── */

.form {
  display: grid;
  gap: 12px;
  margin-bottom: 16px;
}

.verdict-line {
  padding: 12px 14px;
  background: var(--bg);
  border: 1px solid var(--line);
  border-radius: 3px;
  font-size: 14px;
  line-height: 1.7;
}

.bump {
  margin-top: 24px;
}

.impacts {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 6px 24px;
  margin-bottom: 16px;
}

.impacts .check {
  padding: 5px 0;
}

.impacts .check span:nth-child(2) {
  flex: 1;
}

/* ── §08 adoption ────────────────────────────────────────────────────────── */

.progress {
  height: 22px;
  border: 1px solid var(--line-2);
  border-radius: 3px;
  margin-bottom: 12px;
  overflow: hidden;
}

.progress-bar {
  height: 100%;
  background: repeating-linear-gradient(
    -45deg,
    var(--accent) 0 6px,
    color-mix(in srgb, var(--accent) 75%, var(--bg)) 6px 12px
  );
  transition: width 0.3s;
  min-width: 44px;
  display: flex;
  align-items: center;
  justify-content: flex-end;
  padding-right: 6px;
}

.progress-bar::after {
  content: attr(data-label);
  font: 600 11px / 1 var(--mono);
  /* Trim to the digits' cap height and baseline so they center optically. */
  text-box: trim-both cap alphabetic;
  color: var(--accent-ink);
}

.checklist {
  list-style: none;
  margin: 0;
  padding: 0;
}

.checklist li {
  border-bottom: 1px solid var(--line);
}

.checklist .check {
  padding: 8px 0;
  align-items: baseline;
}

.checklist .check:has(input:checked) span:last-child {
  color: var(--muted);
  text-decoration: line-through;
}

.cases input {
  width: 100%;
  margin-bottom: 12px;
}

.cases ul {
  list-style: none;
  margin: 0;
  padding: 0;
  max-height: 520px;
  overflow-y: auto;
}

.cases li {
  padding: 10px 0;
  border-bottom: 1px solid var(--line);
  font-size: 14px;
}

.cases li p {
  margin: 0;
}

.cases .res {
  color: var(--fg-2);
  margin-top: 2px;
}

.changelog ul {
  margin: 8px 0 0;
  padding-left: 18px;
  max-width: 80ch;
}

.changelog li {
  margin-bottom: 8px;
  color: var(--fg-2);
}

/* ── footer ──────────────────────────────────────────────────────────────── */

.foot {
  max-width: var(--max);
  margin: 0 auto;
  padding: 28px var(--gutter) 48px;
  display: flex;
  flex-wrap: wrap;
  gap: 8px 24px;
  justify-content: space-between;
  font: 12px var(--mono);
  color: var(--muted);
}

/* ── responsive ──────────────────────────────────────────────────────────── */

@media (max-width: 900px) {
  .rules {
    grid-template-columns: repeat(2, 1fr);
  }
  .split,
  .lint {
    grid-template-columns: minmax(0, 1fr);
  }
  .editor {
    border-right: 0;
    border-bottom: 1px solid var(--line);
  }
  [data-tree-detail],
  .verdict {
    position: static;
  }
}

@media (max-width: 640px) {
  :root {
    --gutter: 16px;
  }
  .bar nav {
    display: none;
  }
  .bar {
    justify-content: space-between;
  }
  .hero {
    padding: 56px 0 40px;
  }
  .facts {
    grid-template-columns: repeat(2, 1fr);
  }
  .facts div:nth-child(3) {
    padding-left: 0;
    border-left: 0;
  }
  .rules {
    grid-template-columns: 1fr;
  }
  .rules li {
    min-height: 0;
  }
  .sec {
    padding: 52px 0;
  }
  .sec-head {
    grid-template-columns: 1fr;
  }
  .sec-no {
    grid-row: auto;
    padding: 0 0 4px;
  }
  .sec-head h2 {
    font-size: 24px;
  }
  .impacts {
    grid-template-columns: 1fr;
  }
  textarea {
    min-height: 340px;
  }
}