:root {
  color-scheme: light dark;
  --bg: #ffffff;
  --fg: #1f2937;
  --muted: #6b7280;
  --accent: #2563eb;
  --border: #e5e7eb;
  --card: #f9fafb;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0b0f19;
    --fg: #e5e7eb;
    --muted: #9ca3af;
    --accent: #60a5fa;
    --border: #1f2937;
    --card: #111827;
  }
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  line-height: 1.6;
  color: var(--fg);
  background: var(--bg);
}

.site-header,
.site-main,
.site-footer {
  max-width: 44rem;
  margin-inline: auto;
  padding-inline: 1.25rem;
}

.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding-block: 1.25rem;
  border-bottom: 1px solid var(--border);
}

.brand {
  font-weight: 700;
  font-size: 1.1rem;
  text-decoration: none;
  color: var(--fg);
}

.site-nav {
  display: flex;
  gap: 1rem;
}

.site-main {
  padding-block: 2.5rem;
}

.site-footer {
  padding-block: 2rem;
  border-top: 1px solid var(--border);
  color: var(--muted);
  font-size: 0.9rem;
}

h1 {
  font-size: 2rem;
  line-height: 1.2;
  margin-top: 0;
}

a {
  color: var(--accent);
}

.lead {
  font-size: 1.15rem;
  color: var(--muted);
}

.button {
  display: inline-block;
  margin-top: 0.5rem;
  padding: 0.6rem 1rem;
  border-radius: 0.5rem;
  background: var(--accent);
  color: #fff;
  text-decoration: none;
  font-weight: 600;
}

code {
  background: var(--card);
  padding: 0.1rem 0.35rem;
  border-radius: 0.3rem;
  font-size: 0.9em;
}

.stages {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.95rem;
}

.stages th,
.stages td {
  padding: 0.5rem 0.6rem;
  border-bottom: 1px solid var(--border);
  text-align: left;
  vertical-align: top;
}

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

.post pre {
  overflow-x: auto;
  padding: 0.75rem 1rem;
  background: var(--card);
  border-radius: 0.5rem;
}

.post table {
  border-collapse: collapse;
}

.post th,
.post td {
  padding: 0.3rem 0.6rem;
  border: 1px solid var(--border);
}

/* ---- editor ---------------------------------------------------------------------------------- */

body:has(.editor) .site-header,
body:has(.editor) .site-main,
body:has(.editor) .site-footer {
  max-width: 80rem;
}

.stage-head h1 {
  margin-bottom: 0.25rem;
}

.stage-head p {
  margin: 0.25rem 0;
}

.stage-head .meta {
  color: var(--muted);
  display: flex;
  gap: 1rem;
}

.part .label.small {
  font-size: 9px;
}

.workspace {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 22rem;
  gap: 1.5rem;
  align-items: start;
}

@media (max-width: 60rem) {
  .workspace {
    grid-template-columns: 1fr;
  }
}

.board-wrap {
  overflow-x: auto;
}

.board {
  width: 100%;
  height: auto;
  touch-action: none;
  user-select: none;
  --wire: var(--fg);
  --wire-on: #16a34a;
  --short: #dc2626;
}

.board.tool-wire,
.board.tool-cross,
.board.tool-erase,
.board.tool-place {
  cursor: crosshair;
}

.board-bg {
  fill: var(--card);
}

.grid {
  stroke: var(--border);
  stroke-width: 1;
}

.problem {
  fill: rgba(220, 38, 38, 0.25);
}

.wire {
  stroke: var(--wire);
  stroke-width: 4;
  stroke-linecap: round;
  fill: var(--wire);
}

.wire.bus {
  stroke-width: 9;
}

.wire.on {
  stroke: var(--wire-on);
  fill: var(--wire-on);
}

.wire.short {
  stroke: var(--short);
  fill: var(--short);
}

.part rect {
  fill: var(--bg);
  stroke: var(--fg);
  stroke-width: 1.5;
}

.part.prim-relay-on rect {
  fill: color-mix(in srgb, var(--accent) 25%, var(--bg));
}

.part.prim-relay-off rect {
  fill: var(--bg);
  stroke: var(--accent);
}

.part.prim-one rect {
  fill: color-mix(in srgb, #16a34a 30%, var(--bg));
}

.part.selected rect {
  stroke: var(--accent);
  stroke-width: 3;
  stroke-dasharray: 6 3;
}

.part.ghost {
  opacity: 0.5;
}

.part.ghost.bad rect {
  stroke: var(--short);
  fill: rgba(220, 38, 38, 0.2);
}

.part .label {
  text-anchor: middle;
  font-size: 11px;
  font-weight: 600;
  fill: var(--fg);
  pointer-events: none;
}

.pinmark {
  fill: var(--wire);
  stroke: none;
}

.pinmark.on {
  fill: var(--wire-on);
}

.pinmark.short {
  fill: var(--short);
}

.pinname {
  text-anchor: middle;
  font-size: 8px;
  fill: var(--muted);
  pointer-events: none;
}

.pinname.small {
  font-size: 6.5px;
}

.pinmark.bus {
  stroke: var(--bg);
  stroke-width: 1.5;
}

.pin.bus circle {
  stroke-width: 3;
}

.pin.bus text {
  font-size: 10px;
}

.pin .busname {
  font-size: 7px;
  font-weight: 600;
  fill: var(--muted);
}

.pin.on .busname {
  fill: var(--muted);
}

.stub.bus {
  stroke-width: 5;
}

.stub.bus.connected {
  stroke-width: 8;
}

.part.prim-split rect {
  fill: color-mix(in srgb, var(--muted) 20%, var(--bg));
}

.bus-inputs label {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  font-size: 0.9rem;
}

.bus-inputs input {
  width: 4.5rem;
}

.stub {
  stroke: var(--muted);
  stroke-width: 3;
  stroke-dasharray: 3 3;
  fill: none;
}

.stub.connected {
  stroke: var(--wire);
  stroke-dasharray: none;
  stroke-width: 4;
}

.stub.connected.on {
  stroke: var(--wire-on);
}

.stub.short {
  stroke: var(--short);
}

.pin circle {
  fill: var(--bg);
  stroke: var(--fg);
  stroke-width: 2;
}

.pin.in circle {
  cursor: pointer;
}

.pin.on circle {
  fill: var(--wire-on);
  stroke: var(--wire-on);
}

.pin.short circle {
  stroke: var(--short);
}

.pin text {
  text-anchor: middle;
  font-size: 9px;
  font-weight: 700;
  fill: var(--fg);
  pointer-events: none;
}

.pin.on text {
  fill: #fff;
}

.toolbar .group {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem;
  margin-bottom: 0.6rem;
  align-items: center;
}

.toolbar button {
  font: inherit;
  font-size: 0.9rem;
  padding: 0.3rem 0.6rem;
  border: 1px solid var(--border);
  border-radius: 0.4rem;
  background: var(--card);
  color: var(--fg);
  cursor: pointer;
}

.toolbar button.active {
  background: var(--accent);
  border-color: var(--accent);
  color: #fff;
}

.toolbar button:disabled {
  opacity: 0.5;
  cursor: default;
}

.toolbar input[type="number"] {
  width: 4rem;
  font: inherit;
  padding: 0.2rem 0.4rem;
  border: 1px solid var(--border);
  border-radius: 0.4rem;
  background: var(--bg);
  color: var(--fg);
}

.toolbar .hint,
.tests .hint {
  font-size: 0.85rem;
  color: var(--muted);
}

.toolbar .message {
  color: var(--short, #dc2626);
  font-size: 0.9rem;
}

.tests table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.85rem;
  font-variant-numeric: tabular-nums;
}

.tests th,
.tests td {
  padding: 0.2rem 0.4rem;
  border-bottom: 1px solid var(--border);
  text-align: left;
}

.tests tr.ng td:first-child {
  color: #dc2626;
}

.tests tr.ok td:first-child {
  color: #16a34a;
}

.tests tbody tr {
  cursor: pointer;
}

.tests tbody tr:hover {
  background: var(--card);
}

.tests .problems,
.tests .sim-error {
  color: #dc2626;
}

.tests .pass {
  color: #16a34a;
  font-weight: 600;
}

/* ---- library ---------------------------------------------------------------------------------- */

.progress.cleared {
  color: #16a34a;
  font-weight: 600;
}

.library-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  align-items: center;
  margin-bottom: 1rem;
}

.library-actions button,
.library-actions .import {
  font: inherit;
  font-size: 0.9rem;
  padding: 0.3rem 0.6rem;
  border: 1px solid var(--border);
  border-radius: 0.4rem;
  background: var(--card);
  color: var(--fg);
  cursor: pointer;
}

.library-actions .import input {
  display: none;
}

.library-actions .danger {
  margin-left: auto;
  color: #dc2626;
}

.library table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.9rem;
}

.library th,
.library td {
  padding: 0.35rem 0.5rem;
  border-bottom: 1px solid var(--border);
  text-align: left;
  vertical-align: middle;
}

.library td.pins {
  font-family: ui-monospace, monospace;
  font-size: 0.8rem;
  color: var(--muted);
}

.library input[type="text"] {
  font: inherit;
  width: 100%;
  padding: 0.2rem 0.4rem;
  border: 1px solid transparent;
  border-radius: 0.3rem;
  background: transparent;
  color: var(--fg);
}

.library input[type="text"]:hover,
.library input[type="text"]:focus {
  border-color: var(--border);
  background: var(--bg);
}

.library h2 small {
  font-size: 0.8rem;
  color: var(--muted);
  font-weight: 400;
}

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

.library .message,
.toolbar .message {
  color: var(--accent);
}

.register form {
  display: flex;
  gap: 0.4rem;
}

.register input {
  flex: 1;
  font: inherit;
  padding: 0.3rem 0.5rem;
  border: 1px solid var(--border);
  border-radius: 0.4rem;
  background: var(--bg);
  color: var(--fg);
}

.register button {
  font: inherit;
  padding: 0.3rem 0.7rem;
  border: 1px solid var(--accent);
  border-radius: 0.4rem;
  background: var(--accent);
  color: #fff;
  cursor: pointer;
}

.toolbar .group-title {
  font-size: 0.8rem;
  color: var(--muted);
  width: 100%;
}

.tests h3 {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.tests .play {
  font: inherit;
  font-size: 0.8rem;
  padding: 0.15rem 0.5rem;
  border: 1px solid var(--border);
  border-radius: 0.4rem;
  background: var(--card);
  color: var(--fg);
  cursor: pointer;
}

.tests tr.shown {
  background: color-mix(in srgb, var(--accent) 15%, transparent);
}