:root {
  --paper: #f4f7f6;
  --grid-minor: #e4ebe8;
  --grid-major: #d2ddd8;
  --panel: #ffffff;
  --line: #d8e0dd;
  --ink: #1f2a36;
  --ink-muted: #5a6772;
  --shape-fill: #ffffff;
  --shape-stroke: #34414e;
  --accent: #2f5bd3;
  --accent-soft: #e3eafc;
  --buffer: #2f5bd3;
  --danger: #b4332f;
  --c0: #2f5bd3;
  --c1: #0d8576;
  --c2: #b8337a;
  --c3: #a8690e;
  --c4: #6b4fc8;
  --c5: #4d7a24;
  --shadow: 0 1px 2px rgb(31 42 54 / 0.08);
  --font: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  color-scheme: light;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --paper: #1a2027;
    --grid-minor: #212932;
    --grid-major: #2a343f;
    --panel: #20272f;
    --line: #333e4a;
    --ink: #e2e8ee;
    --ink-muted: #9aa7b3;
    --shape-fill: #262f39;
    --shape-stroke: #b9c4cf;
    --accent: #86a3ff;
    --accent-soft: #2a3550;
    --buffer: #86a3ff;
    --danger: #ff8a80;
    --c0: #86a3ff;
    --c1: #3cc7b4;
    --c2: #f07ab8;
    --c3: #e8b04e;
    --c4: #ad96ff;
    --c5: #93c86c;
    --shadow: none;
    color-scheme: dark;
  }
}

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

html {
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font: 14px/1.45 var(--font);
  height: 100dvh;
  display: flex;
  flex-direction: column;
}

a {
  color: var(--accent);
  text-underline-offset: 2px;
}

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

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  overflow: hidden;
  clip-path: inset(50%);
  white-space: nowrap;
}

/* --- masthead ------------------------------------------------------------ */

.masthead {
  display: flex;
  align-items: center;
  gap: 24px;
  padding: 12px 20px;
  border-bottom: 1px solid var(--line);
  background: var(--panel);
}

.masthead-text {
  display: flex;
  align-items: baseline;
  gap: 16px;
  min-width: 0;
  flex: 1;
}

.masthead h1 {
  margin: 0;
  font-size: 17px;
  font-weight: 650;
  letter-spacing: -0.01em;
  white-space: nowrap;
}

.intro {
  margin: 0;
  color: var(--ink-muted);
  max-width: 78ch;
}

.repo-link {
  flex: none;
  font-weight: 550;
  text-decoration: none;
  padding: 6px 12px;
  border: 1px solid var(--line);
  border-radius: 6px;
  color: var(--ink);
}

.repo-link:hover {
  border-color: var(--accent);
  color: var(--accent);
}

/* --- workspace layout ---------------------------------------------------- */

.workspace {
  flex: 1;
  display: grid;
  grid-template-columns: minmax(0, 1fr) 320px;
  min-height: 0;
}

.stage {
  display: flex;
  flex-direction: column;
  min-width: 0;
  min-height: 0;
}

.inspector {
  border-left: 1px solid var(--line);
  background: var(--panel);
  overflow-y: auto;
  overscroll-behavior: contain;
}

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

.toolbar {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  padding: 8px 12px;
  border-bottom: 1px solid var(--line);
  background: var(--panel);
}

.tools,
.zoom {
  display: flex;
  gap: 2px;
}

.toolbar button {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  min-height: 34px;
  padding: 0 10px;
  border: 1px solid transparent;
  border-radius: 6px;
  background: none;
  color: var(--ink);
  font: inherit;
  cursor: pointer;
}

.toolbar button:hover {
  background: var(--accent-soft);
}

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

.toolbar svg {
  width: 18px;
  height: 18px;
  fill: currentColor;
  stroke: currentColor;
  stroke-width: 1.6;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.toolbar [data-tool="move"] svg,
.toolbar [data-tool="box"] svg {
  fill: none;
}

/* --- canvas -------------------------------------------------------------- */

.canvas-wrap {
  position: relative;
  flex: 1;
  min-height: 0;
}

#canvas {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  display: block;
  touch-action: none;
  user-select: none;
  -webkit-user-select: none;
  cursor: default;
}

#canvas.panning {
  cursor: grabbing;
}

#canvas.tool-box,
#canvas.tool-junction {
  cursor: crosshair;
}

.grid-minor {
  stroke: var(--grid-minor);
}

.grid-major {
  stroke: var(--grid-major);
}

.cluster path {
  fill: var(--accent-soft);
  fill-opacity: 0.55;
  stroke: var(--accent);
  stroke-opacity: 0.55;
  stroke-dasharray: 6 4;
}

.cluster text {
  fill: var(--accent);
  font-size: 13px;
  font-weight: 600;
}

.buffer {
  fill: none;
  stroke: var(--buffer);
  stroke-opacity: 0.45;
  stroke-dasharray: 3 3;
}

.shape {
  cursor: grab;
  outline: none;
}

.shape .body {
  fill: var(--shape-fill);
  stroke: var(--shape-stroke);
  stroke-width: 1.4;
}

.shape .label {
  fill: var(--ink);
  font-size: 13px;
  font-weight: 500;
  text-anchor: middle;
  dominant-baseline: central;
  pointer-events: none;
}

.shape.obstacle .body {
  fill: var(--grid-minor);
  stroke: var(--ink-muted);
  stroke-dasharray: 4 3;
}

.shape.obstacle .label {
  fill: var(--ink-muted);
}

.shape.selected .body,
.shape:focus-visible .body {
  stroke: var(--accent);
  stroke-width: 2.4;
}

.pin {
  fill: var(--shape-fill);
  stroke: var(--ink-muted);
  stroke-width: 1.2;
}

.tool-connect .pin {
  fill: var(--accent-soft);
  stroke: var(--accent);
  cursor: crosshair;
}

.tool-connect .shape,
.tool-connect .junction {
  cursor: crosshair;
}

.pin.drop {
  fill: var(--accent);
}

.conn {
  fill: none;
  stroke-width: 2;
  stroke-linejoin: round;
  stroke-linecap: round;
  pointer-events: none;
}

.conn-hit {
  fill: none;
  stroke: transparent;
  stroke-width: 14;
  pointer-events: stroke;
  cursor: pointer;
}

.tool-checkpoint .conn-hit,
.tool-junction .conn-hit {
  cursor: copy;
}

.tool-delete .conn-hit,
.tool-delete .shape,
.tool-delete .junction,
.tool-delete .cluster path {
  cursor: not-allowed;
}

.conn.selected {
  stroke-width: 3.4;
}

.raw {
  fill: none;
  stroke: var(--ink-muted);
  stroke-width: 1;
  stroke-dasharray: 2 3;
  opacity: 0.9;
}

.raw-hidden #layer-raw {
  display: none;
}

.buffers-hidden #layer-buffers {
  display: none;
}

.junction {
  fill: var(--ink);
  stroke: var(--paper);
  stroke-width: 2;
  cursor: grab;
  outline: none;
}

.junction.fixed {
  fill: var(--paper);
  stroke: var(--ink);
}

.junction.selected,
.junction:focus-visible {
  fill: var(--accent);
}

.endpoint {
  fill: var(--paper);
  stroke-width: 2;
  cursor: grab;
}

.checkpoint {
  fill: var(--paper);
  stroke-width: 1.8;
  cursor: grab;
}

.tool-checkpoint .checkpoint,
.tool-delete .checkpoint {
  cursor: pointer;
}

#preview {
  fill: none;
  stroke: var(--accent);
  stroke-width: 1.6;
  stroke-dasharray: 5 4;
  pointer-events: none;
}

.c0 { stroke: var(--c0); color: var(--c0); }
.c1 { stroke: var(--c1); color: var(--c1); }
.c2 { stroke: var(--c2); color: var(--c2); }
.c3 { stroke: var(--c3); color: var(--c3); }
.c4 { stroke: var(--c4); color: var(--c4); }
.c5 { stroke: var(--c5); color: var(--c5); }

.arrow {
  fill: context-stroke;
}

.boot {
  position: absolute;
  inset: 0;
  display: grid;
  place-items: center;
  padding: 24px;
  text-align: center;
  color: var(--ink-muted);
  background: var(--paper);
}

.boot.error {
  color: var(--danger);
  font-weight: 550;
}

.boot[hidden] {
  display: none;
}

/* --- status strip -------------------------------------------------------- */

.status {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 6px 24px;
  padding: 8px 14px;
  border-top: 1px solid var(--line);
  background: var(--panel);
}

.timing {
  display: flex;
  flex-wrap: wrap;
  gap: 2px 20px;
  margin: 0;
}

.timing div {
  display: flex;
  align-items: baseline;
  gap: 6px;
  white-space: nowrap;
}

.timing dt {
  color: var(--ink-muted);
  font-size: 12.5px;
}

.timing dd {
  margin: 0;
  font-weight: 650;
  font-variant-numeric: tabular-nums;
  min-width: 5.2ch;
}

.hint {
  margin: 0;
  color: var(--ink-muted);
  font-size: 12.5px;
  flex: 1;
  min-width: 16ch;
  text-align: right;
}

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

.panel {
  padding: 16px 18px;
  border-bottom: 1px solid var(--line);
}

.panel h2,
.field-label {
  display: block;
  margin: 0 0 10px;
  font-size: 13px;
  font-weight: 650;
}

select {
  width: 100%;
  min-height: 36px;
  padding: 0 10px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: var(--paper);
  color: var(--ink);
  font: inherit;
}

.blurb {
  margin: 10px 0 0;
  color: var(--ink-muted);
}

.selection .blurb {
  margin-top: 0;
  color: var(--ink);
}

.actions {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.actions:not(:empty) {
  margin-top: 12px;
}

.actions button,
.actions label {
  min-height: 32px;
  padding: 0 12px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: var(--paper);
  color: var(--ink);
  font: inherit;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

.actions button:hover {
  border-color: var(--accent);
  color: var(--accent);
}

.actions button.danger:hover {
  border-color: var(--danger);
  color: var(--danger);
}

.segmented {
  display: grid;
  grid-template-columns: 1fr 1fr;
  border: 1px solid var(--line);
  border-radius: 7px;
  padding: 2px;
  background: var(--paper);
}

.segmented label {
  position: relative;
  cursor: pointer;
}

.segmented input {
  position: absolute;
  opacity: 0;
  inset: 0;
  margin: 0;
  cursor: pointer;
}

.segmented span {
  display: block;
  padding: 6px 0;
  border-radius: 5px;
  text-align: center;
  font-weight: 550;
  color: var(--ink-muted);
}

.segmented input:checked + span {
  background: var(--panel);
  color: var(--ink);
  box-shadow: var(--shadow), 0 0 0 1px var(--line);
}

.segmented input:focus-visible + span {
  outline: 2px solid var(--accent);
  outline-offset: 1px;
}

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

.param-head {
  display: flex;
  justify-content: space-between;
  gap: 8px;
}

.param-head label {
  font-weight: 500;
}

.param output {
  font-variant-numeric: tabular-nums;
  font-weight: 600;
}

.param .scope {
  color: var(--ink-muted);
  font-size: 12px;
  font-weight: 400;
}

.param input[type="range"] {
  width: 100%;
  margin: 6px 0 0;
  accent-color: var(--accent);
}

.param .param-hint {
  display: none;
  margin: 2px 0 0;
  font-size: 12.5px;
  color: var(--ink-muted);
}

.param:focus-within .param-hint,
.param:hover .param-hint {
  display: block;
}

.param.inactive label,
.param.inactive output {
  color: var(--ink-muted);
}

.param.inactive input[type="range"] {
  opacity: 0.5;
}

.text-button {
  margin-top: 14px;
  padding: 0;
  border: 0;
  background: none;
  color: var(--accent);
  font: inherit;
  cursor: pointer;
  text-decoration: underline;
  text-underline-offset: 2px;
}

.checks {
  display: grid;
  gap: 8px;
}

.checks label {
  display: flex;
  gap: 8px;
  align-items: flex-start;
  cursor: pointer;
}

.checks input {
  margin: 2px 0 0;
  flex: none;
  accent-color: var(--accent);
  width: 16px;
  height: 16px;
}

.checks label.inactive {
  color: var(--ink-muted);
}

.colophon {
  padding: 16px 18px 24px;
  color: var(--ink-muted);
  font-size: 12.5px;
}

.colophon p {
  margin: 0;
}

/* --- narrow screens ------------------------------------------------------ */

@media (max-width: 900px) {
  body {
    height: auto;
  }

  .masthead {
    flex-wrap: wrap;
    gap: 8px;
    padding: 10px 16px;
  }

  .masthead-text {
    flex-direction: column;
    gap: 2px;
  }

  .repo-link {
    display: none;
  }

  .workspace {
    display: block;
    height: auto;
  }

  .intro {
    font-size: 13.5px;
  }

  .stage {
    height: min(62dvh, 560px);
    min-height: 360px;
  }

  .inspector {
    border-left: 0;
    border-top: 1px solid var(--line);
    overflow: visible;
  }

  .panel {
    padding: 14px 16px;
  }

  .toolbar {
    padding: 6px 8px;
    overflow-x: auto;
  }

  .hint {
    text-align: left;
    flex-basis: 100%;
  }
}

@media (max-width: 600px) {
  .toolbar button span {
    display: none;
  }

  .toolbar button {
    padding: 0 8px;
  }

  .timing {
    gap: 2px 14px;
  }

  .status {
    padding: 8px 12px;
  }
}

@media (prefers-reduced-motion: no-preference) {
  .toolbar button,
  .actions button,
  .repo-link {
    transition: background-color 120ms, border-color 120ms, color 120ms;
  }
}