/* Symmetric Brownian motion — a large paper-like field with compact controls. */

body.brownian-page { min-width: 320px; }

.site-header nav a[aria-current="page"] {
  color: var(--text);
  font-weight: 650;
  text-decoration-color: var(--accent);
}

main.brownian {
  max-width: 1160px;
  padding-top: clamp(1.6rem, 4vw, 3.2rem);
}

.brownian-intro {
  max-width: 850px;
  margin-bottom: 1.5rem;
}

.brownian-intro .eyebrow {
  margin: 0 0 0.35rem;
  color: var(--accent);
  font: 600 0.76rem/1.4 ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

.brownian-intro h1 {
  margin-top: 0;
  font-size: clamp(2rem, 4.8vw, 3.65rem);
  line-height: 1.06;
  letter-spacing: -0.035em;
}

.brownian-intro .subtitle {
  max-width: 790px;
  color: var(--muted);
  font-size: clamp(1rem, 1.8vw, 1.15rem);
  line-height: 1.55;
}

.brownian-lab {
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: var(--background);
  box-shadow: 0 1px 3px rgba(20, 35, 29, 0.08), 0 8px 24px rgba(20, 35, 29, 0.05);
}

.brownian-toolbar {
  display: flex;
  align-items: end;
  gap: 0.7rem 0.9rem;
  padding: 0.8rem 0.9rem;
  border-bottom: 1px solid var(--line);
  font-family: ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
}

.brownian-toolbar .group-picker {
  flex: 1 1 430px;
  display: grid;
  gap: 0.25rem;
  color: var(--muted);
  font-size: 0.74rem;
  letter-spacing: 0.055em;
  text-transform: uppercase;
}

.brownian-toolbar select,
.brownian-toolbar button,
.brownian-playbar button,
.density-buttons button {
  min-height: 2.55rem;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: var(--surface);
  color: var(--text);
  cursor: pointer;
  font: 0.9rem/1.2 ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
}

.brownian-toolbar select {
  width: 100%;
  padding: 0 2.4rem 0 0.7rem;
}

.brownian-toolbar button { padding: 0 1rem; }

.brownian-toolbar button.primary {
  border-color: var(--accent);
  background: var(--accent);
  color: var(--background);
  font-weight: 650;
}

.brownian-toolbar button:hover,
.brownian-playbar button:hover,
.density-buttons button:hover { border-color: var(--accent); color: var(--accent); }

.brownian-toolbar button.primary:hover {
  border-color: #005d53;
  background: #005d53;
  color: var(--background);
}

.brownian-toolbar button:disabled,
.brownian-toolbar select:disabled,
.brownian-playbar button:disabled,
.density-buttons button:disabled,
.temperature input:disabled { cursor: wait; opacity: 0.55; }

.brownian-toolbar .check {
  min-height: 2.55rem;
  display: inline-flex;
  align-items: center;
  gap: 0.42rem;
  color: var(--muted);
  cursor: pointer;
  font: 0.84rem/1.25 ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
  white-space: nowrap;
}

.brownian-toolbar input,
.advanced-grid input { accent-color: var(--accent); }

.brownian-stage {
  position: relative;
  min-height: 360px;
  background: var(--background);
  cursor: pointer;
  outline: none;
}

.brownian-stage:focus-visible {
  box-shadow: inset 0 0 0 3px var(--accent);
}

#brownian-canvas {
  display: block;
  width: 100%;
  height: clamp(420px, 64vh, 700px);
  background: var(--background);
}

.stage-overlay {
  position: absolute;
  top: 0.8rem;
  left: 0.85rem;
  display: inline-flex;
  align-items: baseline;
  gap: 0.5rem;
  padding: 0.28rem 0.55rem;
  border: 1px solid rgba(120, 116, 104, 0.22);
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.9);
  color: var(--text);
  pointer-events: none;
  backdrop-filter: blur(5px);
  font: 600 0.78rem/1.2 ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
}

.stage-overlay .sym {
  color: var(--accent);
  font: 1.06rem/1 ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
}

.stage-hint {
  position: absolute;
  right: 0.85rem;
  bottom: 0.65rem;
  margin: 0;
  padding: 0.25rem 0.45rem;
  border-radius: 4px;
  background: rgba(255, 255, 255, 0.84);
  color: var(--muted);
  pointer-events: none;
  font: 0.75rem/1.25 ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
}

.brownian-playbar {
  display: flex;
  align-items: stretch;
  gap: 1rem;
  padding: 0.75rem 0.9rem;
  border-top: 1px solid var(--line);
  font-family: ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
}

.brownian-playbar > button {
  flex: 0 0 7.5rem;
  padding: 0 0.9rem;
  background: var(--surface-raised);
}

.brownian-playbar > button .icon {
  display: inline-block;
  width: 1.35rem;
  color: var(--accent);
}

.brownian-stats {
  flex: 1 1 auto;
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 0.5rem 1.2rem;
  margin: 0;
}

.brownian-stats > div {
  min-width: 0;
  padding-left: 0.8rem;
  border-left: 1px solid var(--line);
}

.brownian-stats dt {
  overflow: hidden;
  color: var(--muted);
  font-size: 0.7rem;
  letter-spacing: 0.055em;
  text-overflow: ellipsis;
  text-transform: uppercase;
  white-space: nowrap;
}

.brownian-stats dd {
  margin: 0.12rem 0 0;
  overflow: hidden;
  color: var(--text);
  font-size: 0.9rem;
  font-variant-numeric: tabular-nums;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.brownian-notes { margin-top: 1.15rem; }

.group-reading {
  display: grid;
  grid-template-columns: 8rem 1fr;
  gap: 1rem;
  align-items: baseline;
  padding: 0.75rem 0.2rem;
}

.group-reading p { margin: 0; }

.group-reading .note-label,
.control-label {
  color: var(--muted);
  font: 0.74rem/1.4 ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
  letter-spacing: 0.065em;
  text-transform: uppercase;
}

.brownian-notes details { margin-top: 0.35rem; }

.advanced-grid {
  display: grid;
  grid-template-columns: minmax(250px, 0.85fr) minmax(240px, 1.15fr);
  gap: 1.2rem 2rem;
  align-items: end;
  padding-top: 0.45rem;
  font-family: ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
}

.density-buttons {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 0.3rem;
  margin-top: 0.3rem;
}

.density-buttons button {
  min-height: 2.2rem;
  padding: 0.3rem 0.5rem;
  font-size: 0.8rem;
}

.density-buttons button[aria-pressed="true"] {
  border-color: var(--accent);
  background: var(--surface-raised);
  color: var(--accent);
  font-weight: 650;
}

.temperature {
  display: grid;
  gap: 0.35rem;
  color: var(--muted);
  font: 0.82rem/1.3 ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
}

.temperature span { display: flex; justify-content: space-between; gap: 1rem; }
.temperature output { color: var(--text); font-variant-numeric: tabular-nums; }
.temperature input { width: 100%; }

.optimizer-copy {
  margin: 0.85rem 0 0;
  color: var(--muted);
  font: 0.8rem/1.5 ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
}

.method-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1rem;
  margin-top: 1.2rem;
}

.method-grid article {
  padding: 1rem 1.05rem;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--background);
}

.method-grid h2 {
  margin: 0 0 0.35rem;
  padding: 0;
  border: 0;
  font: 650 0.9rem/1.3 ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
}

.method-grid p {
  margin: 0;
  color: var(--muted);
  font-size: 0.9rem;
  line-height: 1.5;
}

.visually-hidden {
  position: absolute !important;
  width: 1px !important;
  height: 1px !important;
  padding: 0 !important;
  margin: -1px !important;
  overflow: hidden !important;
  clip: rect(0 0 0 0) !important;
  white-space: nowrap !important;
  border: 0 !important;
}

@media (max-width: 800px) {
  main.brownian { padding-inline: 0.8rem; }
  .brownian-toolbar { align-items: center; flex-wrap: wrap; }
  .brownian-toolbar .group-picker { flex-basis: 100%; }
  .brownian-toolbar button.primary { flex: 1 1 auto; }
  .brownian-playbar { flex-direction: column; gap: 0.7rem; }
  .brownian-playbar > button { flex-basis: 2.55rem; }
  .brownian-stats > div:first-child { border-left: 0; padding-left: 0; }
  .method-grid { grid-template-columns: 1fr; }
}

@media (max-width: 560px) {
  .brownian-intro h1 { font-size: 2.25rem; }
  #brownian-canvas { height: clamp(340px, 58svh, 500px); }
  .brownian-toolbar .check { flex: 1 1 calc(50% - 0.5rem); min-height: 2.25rem; }
  .brownian-stats { grid-template-columns: repeat(2, 1fr); }
  .brownian-stats > div:nth-child(3) { border-left: 0; padding-left: 0; }
  .group-reading { grid-template-columns: 1fr; gap: 0.15rem; }
  .advanced-grid { grid-template-columns: 1fr; }
  .stage-hint { display: none; }
}

@media (prefers-reduced-motion: reduce) {
  .stage-hint { display: none; }
}