/* Topology Optimizer — drafting-sheet aesthetic */

:root {
  --desk: #dfe1d8;
  --paper: #f6f7f2;
  --sheet-white: #fdfdfa;
  --ink: #20262d;
  --ink-soft: #4a545e;
  --ink-faint: #98a0a7;
  --hairline: #c9cec9;
  --blue: #2b5aa6;
  --cyan: #8fb9c9;
  --red: #c23d26;
  --grid: rgba(43, 90, 166, 0.055);
  --grid-major: rgba(43, 90, 166, 0.11);
  --font-display: "Saira Condensed", "Arial Narrow", sans-serif;
  --font-mono: "IBM Plex Mono", ui-monospace, monospace;
}

* { margin: 0; padding: 0; box-sizing: border-box; }

html, body { height: 100%; }

body {
  background: var(--desk);
  color: var(--ink);
  font-family: var(--font-mono);
  font-size: 13px;
  line-height: 1.45;
}

button { font: inherit; color: inherit; background: none; border: none; cursor: pointer; }

:focus-visible { outline: 2px dashed var(--blue); outline-offset: 2px; }

.desk {
  min-height: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 20px 16px;
}

.sheet {
  width: 100%;
  max-width: 1280px;
  background: var(--paper);
  border: 2px solid var(--ink);
  box-shadow: 0 14px 40px rgba(32, 38, 45, 0.18);
}

.sheet-inner {
  margin: 5px;
  border: 1px solid var(--ink-faint);
  display: flex;
  flex-direction: column;
}

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

.masthead {
  display: flex;
  align-items: stretch;
  justify-content: space-between;
  gap: 16px;
  border-bottom: 2px solid var(--ink);
  padding: 10px 16px;
}

.masthead-title h1 {
  font-family: var(--font-display);
  font-size: 24px;
  font-weight: 700;
  letter-spacing: 0.09em;
  text-transform: uppercase;
  line-height: 1.1;
}

.masthead-sub {
  font-size: 10px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--ink-soft);
}

.masthead-specs {
  display: flex;
  align-items: stretch;
}

.masthead-specs > div {
  border-left: 1px solid var(--hairline);
  padding: 2px 14px;
  min-width: 86px;
}

.masthead-specs dt {
  font-size: 9px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--ink-faint);
}

.masthead-specs dd {
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 500;
  margin-top: 2px;
  white-space: nowrap;
}

/* ---------- work area ---------- */

.work {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 300px;
}

.stage {
  display: flex;
  flex-direction: column;
  padding: 10px 10px 0;
  background-image:
    linear-gradient(var(--grid-major) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid-major) 1px, transparent 1px),
    linear-gradient(var(--grid) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid) 1px, transparent 1px);
  background-size: 80px 80px, 80px 80px, 16px 16px, 16px 16px;
}

#field {
  display: block;
  width: 100%;
  flex: 1;
  touch-action: none;
  cursor: crosshair;
}

.statusbar {
  display: flex;
  gap: 18px;
  align-items: baseline;
  border-top: 1px solid var(--hairline);
  margin-top: 8px;
  padding: 7px 6px;
  font-size: 11px;
  min-height: 32px;
}

#status-state {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 12px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--blue);
  white-space: nowrap;
}

#status-state.warn { color: var(--red); }

#status-hint { color: var(--ink-soft); }

/* ---------- panel ---------- */

.panel {
  border-left: 2px solid var(--ink);
  display: flex;
  flex-direction: column;
  background: var(--paper);
}

.block {
  padding: 12px 14px 14px;
  border-bottom: 1px solid var(--hairline);
}

.block-label {
  font-family: var(--font-display);
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--ink-soft);
  margin-bottom: 10px;
}

/* presets */

.preset-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 8px;
}

.preset {
  border: 1px solid var(--ink-soft);
  background: var(--sheet-white);
  padding: 7px 6px 5px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 3px;
  transition: background 120ms, color 120ms;
}

.preset svg { width: 52px; height: 31px; overflow: visible; }

.preset span {
  font-family: var(--font-display);
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

.preset:hover { border-color: var(--blue); color: var(--blue); }

.preset[aria-pressed="true"] {
  background: var(--ink);
  border-color: var(--ink);
  color: var(--paper);
}

.ps-domain { fill: none; stroke: currentColor; stroke-width: 0.8; opacity: 0.55; }
.ps-wall { stroke: currentColor; stroke-width: 1.6; }
.ps-hatch { stroke: currentColor; stroke-width: 0.8; }
.ps-pin { fill: currentColor; }
.ps-force { stroke: var(--red); stroke-width: 1.4; }
.ps-head { fill: var(--red); }

.preset[aria-pressed="true"] .ps-force { stroke: #e2664a; }
.preset[aria-pressed="true"] .ps-head { fill: #e2664a; }

/* tools */

.tool-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 6px;
}

.tool {
  border: 1px solid var(--ink-soft);
  background: var(--sheet-white);
  padding: 6px 2px 4px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 2px;
  transition: background 120ms, color 120ms;
}

.tool svg { width: 20px; height: 20px; }

.tool span {
  font-family: var(--font-display);
  font-size: 10px;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

.tool:hover { border-color: var(--blue); color: var(--blue); }

.tool[aria-pressed="true"] {
  background: var(--blue);
  border-color: var(--blue);
  color: var(--paper);
}

.ti-line { stroke: currentColor; stroke-width: 1.3; fill: none; }
.ti-dash { stroke: currentColor; stroke-width: 1.1; fill: none; stroke-dasharray: 2.4 2; }
.ti-force { stroke: var(--red); stroke-width: 1.6; }
.ti-head { fill: var(--red); }

.tool[aria-pressed="true"] .ti-force { stroke: #ffd9cf; }
.tool[aria-pressed="true"] .ti-head { fill: #ffd9cf; }

/* controls */

.control-row {
  display: grid;
  grid-template-columns: 92px 1fr 44px;
  align-items: center;
  gap: 8px;
  margin-bottom: 10px;
}

.control-row:last-child { margin-bottom: 0; }

.control-row label,
.control-row .control-label {
  font-size: 10px;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--ink-soft);
}

.control-row label sub { text-transform: none; }

.control-row output {
  font-size: 12px;
  font-weight: 500;
  text-align: right;
}

input[type="range"] {
  -webkit-appearance: none;
  appearance: none;
  width: 100%;
  height: 18px;
  background: transparent;
}

input[type="range"]::-webkit-slider-runnable-track {
  height: 2px;
  background: var(--ink-faint);
}

input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 11px;
  height: 11px;
  margin-top: -4.5px;
  background: var(--paper);
  border: 2px solid var(--ink);
}

input[type="range"]::-moz-range-track {
  height: 2px;
  background: var(--ink-faint);
}

input[type="range"]::-moz-range-thumb {
  width: 7px;
  height: 7px;
  border-radius: 0;
  background: var(--paper);
  border: 2px solid var(--ink);
}

input[type="range"]:hover::-webkit-slider-thumb { border-color: var(--blue); }
input[type="range"]:hover::-moz-range-thumb { border-color: var(--blue); }

.seg { display: flex; }

.seg button {
  flex: 1;
  border: 1px solid var(--ink-soft);
  border-right-width: 0;
  background: var(--sheet-white);
  padding: 4px 2px;
  font-size: 10.5px;
  letter-spacing: 0.04em;
}

.seg button:last-child { border-right-width: 1px; }

.seg button:hover { color: var(--blue); }

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

/* run */

.run-btn {
  width: 100%;
  background: var(--ink);
  color: var(--paper);
  font-family: var(--font-display);
  font-size: 14px;
  font-weight: 700;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  padding: 11px 8px;
  transition: background 120ms;
}

.run-btn:hover { background: var(--blue); }

.run-btn.running { background: var(--blue); }

.run-aux {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 6px;
  margin-top: 6px;
}

.run-aux button {
  border: 1px solid var(--ink-soft);
  background: var(--sheet-white);
  font-family: var(--font-display);
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  padding: 6px 4px;
}

.run-aux button:hover { border-color: var(--red); color: var(--red); }

/* ---------- title block ---------- */

.titleblock {
  margin-top: auto;
  border-top: 2px solid var(--ink);
  background: var(--sheet-white);
}

.tb-stats {
  display: grid;
  grid-template-columns: 1fr 1fr;
}

.tb-cell {
  border-bottom: 1px solid var(--hairline);
  padding: 6px 12px 5px;
  display: flex;
  flex-direction: column;
}

.tb-cell:nth-child(odd) { border-right: 1px solid var(--hairline); }

.tb-k {
  font-size: 8.5px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--ink-faint);
}

.tb-k em { font-style: normal; color: var(--blue); }

.no-caps { text-transform: none; }

.tb-v {
  font-size: 15px;
  font-weight: 500;
  font-variant-numeric: tabular-nums;
  margin-top: 1px;
}

.tb-spark {
  padding: 6px 12px 4px;
  border-bottom: 1px solid var(--hairline);
}

#spark {
  display: block;
  width: 100%;
  height: 44px;
  margin-top: 4px;
  cursor: crosshair;
}

.tb-credits {
  display: flex;
  justify-content: space-between;
  gap: 8px;
  padding: 5px 12px;
  font-size: 8.5px;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--ink-faint);
}

/* ---------- margin note ---------- */

.margin-note {
  border-top: 2px solid var(--ink);
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 24px;
  padding: 8px 16px;
  font-size: 10.5px;
  color: var(--ink-soft);
}

.margin-cite {
  white-space: nowrap;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  font-size: 9px;
  color: var(--ink-faint);
}

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

@media (max-width: 900px) {
  .desk { padding: 10px 8px; }

  .work { grid-template-columns: 1fr; }

  .panel { border-left: none; border-top: 2px solid var(--ink); }

  .stage { min-height: 46vh; }

  .masthead { flex-wrap: wrap; }

  .masthead-specs > div:first-child { border-left: none; padding-left: 0; }

  .margin-note { flex-direction: column; gap: 4px; }

  .margin-cite { white-space: normal; }
}