:root {

  --bg: #ffffff;

  --fg: #0f172a;          /* slate-900 */

  --accent: #2563eb;      /* blue-600 */

  --ok: #16a34a;          /* green-600 */

  --warn: #dc2626;        /* red-600 */

  --muted: #64748b;       /* slate-500 */

  --grid: #e2e8f0;        /* slate-200 */

  --codeBg: #0b1020;      /* deep code bg (dark by default for code) */



  --card: #f8fafc;

  --shadow: 0 4px 14px rgba(0,0,0,.08);



  --cell-size: 56px;

  --cell-gap: 8px;



  --anim-pointer: 200ms cubic-bezier(0.2, 0.8, 0.2, 1);

  --anim-pulse: 400ms cubic-bezier(0.2, 0.8, 0.2, 1);

  --anim-flash: 120ms linear;

  --anim-comment: 150ms ease;

  --step-interval: 700ms; /* base, scaled by speed */



  color-scheme: light;

}



:root.dark {

  --bg: #0b1220;

  --fg: #e5e7eb;

  --accent: #60a5fa;

  --ok: #22c55e;

  --warn: #f87171;

  --muted: #94a3b8;

  --grid: #1f2937;

  --card: #0f172a;

  --codeBg: #0b1020;

  color-scheme: dark;

}



:root.hc {

  --accent: #ffb000;

  --ok: #00ff6a;

  --warn: #ff375f;

  --muted: #d0d0d0;

  --grid: #8a8a8a;

  --shadow: 0 0 0 2px var(--accent);

}



* { box-sizing: border-box; }



html, body {

  height: 100%;

}



body {

  margin: 0;

  font: 15px/1.45 system-ui, -apple-system, Segoe UI, Roboto, Ubuntu, Cantarell, Noto Sans, 'Helvetica Neue', Arial, 'Apple Color Emoji', 'Segoe UI Emoji';

  background: var(--bg);

  color: var(--fg);

}



.app {

  display: grid;

  grid-template-rows: auto auto 1fr auto auto;

  min-height: 100vh;

}



.header {

  display: grid;

  gap: 12px;

  padding: 16px clamp(12px, 2vw, 24px);

  border-bottom: 1px solid var(--grid);

  background: var(--card);

}



.title-wrap .title {

  margin: 0;

  font-weight: 800;

  font-size: clamp(18px, 2.2vw, 28px);

}

.subtitle { margin: 4px 0 0 0; color: var(--muted); }



.input-form {

  display: grid;

  grid-template-columns: 1fr 2fr auto auto;

  gap: 12px;

  align-items: end;

}

@media (max-width: 900px) {

  .input-form { grid-template-columns: 1fr; }

}

.field { display: grid; gap: 6px; }

.field.grow { width: 100%; }

.field input, .field select {

  width: 100%;

  height: 36px;

  padding: 8px 10px;

  border: 1px solid var(--grid);

  border-radius: 10px;

  background: var(--bg);

  color: var(--fg);

  box-shadow: var(--shadow);

}

.toggles { display: flex; align-items: center; gap: 10px; }

.toggle { display: inline-flex; gap: 6px; align-items: center; font-weight: 600; }

.actions { display: flex; gap: 8px; justify-content: flex-end; }

.btn {

  appearance: none;

  border: 1px solid var(--grid);

  border-radius: 10px;

  background: var(--bg);

  color: var(--fg);

  padding: 8px 12px;

  cursor: pointer;

  box-shadow: var(--shadow);

  transition: transform .06s ease, background .15s ease;

}

.btn:hover { transform: translateY(-1px); }

.btn:active { transform: translateY(0); }

.btn.accent { background: var(--accent); border-color: transparent; color: white; }



.error { color: var(--warn); font-weight: 700; }

.error[hidden] { display: none; }



.controls {

  display: grid;

  grid-template-columns: auto 1fr auto;

  gap: 12px;

  align-items: center;

  padding: 10px clamp(12px, 2vw, 24px);

  border-bottom: 1px solid var(--grid);

}

.controls .buttons { display: flex; gap: 8px; }

.speed {

  display: grid; place-items: center;

  gap: 4px;

}

.speed input[type="range"] { width: min(420px, 80vw); }

.speed-labels { display: flex; justify-content: space-between; gap: 8px; width: min(420px, 80vw); font-size: 12px; color: var(--muted); }

.hints { color: var(--muted); text-align: right; }



.main {

  display: grid;

  grid-template-columns: 1fr minmax(260px, 360px);

  grid-template-rows: auto 1fr;

  gap: 12px;

  padding: 12px clamp(12px, 2vw, 24px);

}

@media (max-width: 960px) {

  .main { grid-template-columns: 1fr; grid-template-rows: auto auto auto; }

}



.array-pane {

  min-height: 180px;

  border: 1px dashed var(--grid);

  border-radius: 14px;

  position: relative;

  overflow: auto;

  padding: 18px;

  background:

    linear-gradient(transparent 23px, var(--grid) 24px, transparent 24px) top left/100% 24px no-repeat;

}

.array-inner {

  display: grid;

  grid-auto-flow: column;

  grid-auto-columns: var(--cell-size);

  gap: var(--cell-gap);

  position: relative;

  padding-bottom: 52px; /* space for underline & pointers */

}

.cell {

  position: relative;

  display: grid;

  place-items: center;

  height: var(--cell-size);

  width: var(--cell-size);

  border-radius: 12px;

  background: var(--card);

  color: var(--fg);

  border: 1px solid var(--grid);

  box-shadow: var(--shadow);

  font-weight: 800;

  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace;

}

.cell .idx {

  position: absolute;

  top: -18px;

  font: 11px/1 ui-monospace, Consolas, monospace;

  color: var(--muted);

}

.pointer {

  position: absolute;

  top: -28px;

  width: var(--cell-size);

  height: 20px;

  display: grid;

  place-items: center;

  color: var(--accent);

  font-weight: 900;

  transition: transform var(--anim-pointer);

  will-change: transform;

  pointer-events: none;

}

.pointer.right { color: #a855f7; } /* purple-500 */

.pointer .label {

  position: absolute;

  top: -14px;

  font-size: 11px;

  color: var(--muted);

}



.windowOverlay {

  position: absolute;

  height: calc(var(--cell-size) + 4px);

  background: color-mix(in oklab, var(--accent) 18%, transparent);

  border: 2px solid var(--accent);

  border-radius: 12px;

  top: 0;

  transition: transform var(--anim-pointer), width var(--anim-pointer), opacity .2s ease;

  pointer-events: none;

}

.windowOverlay .tooMany {

  position: absolute;

  top: -18px;

  left: 12px;

  right: 12px;

  height: 6px;

  border-radius: 6px;

  background: var(--warn);

  opacity: 0;

  transition: opacity .2s ease;

}

.windowOverlay.too-many .tooMany { opacity: 1; }

.windowOverlay::after {

  content: attr(aria-label);

  position: absolute;

  bottom: -18px;

  left: 8px;

  right: 8px;

  font-size: 11px;

  color: var(--muted);

}



.zeroBadge {

  position: absolute;

  bottom: -6px;

  left: 50%;

  transform: translateX(-50%) scale(1);

  background: var(--warn);

  color: #fff;

  font-size: 10px;

  font-weight: 900;

  height: 16px;

  min-width: 16px;

  padding: 0 4px;

  border-radius: 10px;

  display: grid; place-items: center;

  box-shadow: 0 2px 6px rgba(0,0,0,.2);

  transition: transform .12s ease;

}

.zeroBadge.pop { transform: translateX(-50%) scale(1.2); }



.bestLayer {

  position: absolute;

  bottom: 8px;

  left: 0;

  right: 0;

  height: 8px;

  pointer-events: none;

}

.bestUnderline {

  position: absolute;

  height: 4px;

  background: var(--ok);

  border-radius: 6px;

  box-shadow: 0 0 0 2px color-mix(in oklab, var(--ok) 35%, transparent);

}

.bestUnderline.pulse { animation: pulse var(--anim-pulse); }

.bestBracket {

  position: absolute;

  bottom: 14px;

  font-size: 12px;

  color: var(--ok);

}



.debugger {

  display: grid;

  gap: 12px;

}



.registers, .code-pane, .comment-pane {

  border: 1px solid var(--grid);

  border-radius: 14px;

  padding: 12px;

  background: var(--card);

  box-shadow: var(--shadow);

}



.registers h2, .code-pane h2, .comment-pane h2 { margin: 0 0 8px 0; font-size: 14px; color: var(--muted); }

.reg-grid {

  display: grid;

  grid-template-columns: repeat(3, 1fr);

  gap: 6px;

}

.reg { display: flex; justify-content: space-between; gap: 12px; padding: 6px 8px; border-radius: 10px; }

.reg .k { font-weight: 700; color: var(--muted); }

.reg .v { font-weight: 900; }

.reg.flash { animation: flash var(--anim-flash); }



.code-pane .code {

  margin: 0;

  padding: 12px;

  border-radius: 10px;

  background: var(--codeBg);

  color: #dbeafe; /* blue-100 */

  font: 13px/1.4 ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", "Courier New";

  overflow: auto;

  max-height: 320px;

  counter-reset: line;

}

.code .hl { background: rgba(96, 165, 250, 0.22); display: inline-block; width: 100%; }

.code .ln { color: #64748b; user-select: none; display: inline-block; width: 28px; text-align: right; padding-right: 8px; }

.code .src { display: inline-block; white-space: pre; width: calc(100% - 28px); }



.comment-pane .comment {

  min-height: 40px;

  font-weight: 600;

  transition: opacity var(--anim-comment);

}



.timeline {

  position: relative;

  display: grid;

  gap: 8px;

  padding: 10px clamp(12px, 2vw, 24px) 16px;

  border-top: 1px solid var(--grid);

  background: var(--card);

}

.timeline .bars {

  position: relative;

  display: grid;

  grid-auto-flow: column;

  gap: 2px;

}

.timeline .bar {

  height: 16px;

  border-radius: 4px;

  background: var(--grid);

  cursor: pointer;

}

.bar.init, .bar.final { background: #cbd5e1; }

.bar.expand { background: #93c5fd; }

.bar.shrink { background: #fbbf24; }

.bar.compute { background: #c4b5fd; }

.bar.updateBest { background: #86efac; }



.timeline .handle {

  position: absolute;

  top: -2px;

  height: 22px;

  width: 2px;

  background: var(--accent);

  border-radius: 2px;

  box-shadow: 0 0 0 2px color-mix(in oklab, var(--accent) 40%, transparent);

  pointer-events: none;

  transform: translateX(0);

  transition: transform var(--anim-pointer);

}

.timeline .milestone {

  position: absolute;

  top: -6px;

  height: 28px;

  width: 6px;

  border-radius: 3px;

  background: #ef4444;

  opacity: .9;

  pointer-events: none;

}



.footer {

  padding: 12px clamp(12px, 2vw, 24px) 24px;

  color: var(--muted);

}



.sr-only {

  position: absolute !important;

  width: 1px; height: 1px;

  padding: 0; margin: -1px;

  overflow: hidden; clip: rect(0,0,0,0); white-space: nowrap; border: 0;

}



/* Animations */

@keyframes pulse {

  0% { transform: scaleX(1) }

  35% { transform: scaleX(1.06) }

  100% { transform: scaleX(1) }

}

@keyframes flash {

  0% { background: rgba(96,165,250,.55); }

  100% { background: transparent; }

}



/* Reduced motion */

@media (prefers-reduced-motion: reduce) {

  :root {

    --anim-pointer: 1ms linear;

    --anim-pulse: 1ms linear;

    --anim-flash: 1ms linear;

    --anim-comment: 1ms linear;

  }

}