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

body {
  background: #0f172a;
  color: white;
  font-family: Arial, Helvetica, sans-serif;
  text-align: center;
  margin: 0;
  min-height: 100vh;
}

.page-header {
  padding: 0.85rem 1rem 0.35rem;
}

.page-header h1 {
  margin: 0 0 0.4rem;
}

.page-header p {
  margin: 0;
  color: #cbd5e1;
  max-width: 40rem;
  margin-left: auto;
  margin-right: auto;
}

.theory-eyebrow {
  margin: 0.65rem 0 0;
  font-size: 0.95rem;
  font-weight: 600;
  color: #94a3b8;
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

.theory-section {
  max-width: 100%;
  margin: 0 auto;
  padding: 0.35rem clamp(0.5rem, 2vw, 1rem) 2rem;
}

.main-layout {
  display: grid;
  grid-template-columns: minmax(220px, 1fr) minmax(260px, min(100%, 800px)) minmax(220px, 1fr);
  grid-template-areas: "left sim right";
  gap: 0.85rem 1rem;
  align-items: start;
  justify-content: center;
  max-width: min(100%, 1600px);
  margin: 0 auto;
}

.theory-panel--left {
  grid-area: left;
}

.theory-panel--right {
  grid-area: right;
}

.sim-column {
  grid-area: sim;
  display: flex;
  flex-direction: column;
  align-items: center;
  min-width: 0;
  width: 100%;
  max-width: 800px;
  margin: 0 auto;
}

canvas {
  display: block;
  width: 100%;
  max-width: 800px;
  height: auto;
  margin: 0 auto 10px;
  background: #020617;
  border: 1px solid #334155;
}

.mode-text {
  width: 100%;
  max-width: 42rem;
  margin: 4px auto 6px;
  padding: 0 8px;
  font-size: 0.98rem;
  line-height: 1.45;
  color: #e2e8f0;
  font-weight: 500;
}

.rt-text {
  margin: 0 auto 8px;
  font-size: 0.9rem;
  font-variant-numeric: tabular-nums;
  color: #94a3b8;
}

.controls {
  margin-top: 8px;
  margin-bottom: 4px;
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 24px;
  width: 100%;
}

label {
  display: inline-flex;
  align-items: center;
  gap: 8px;
}

input[type="range"] {
  vertical-align: middle;
}

.val {
  font-variant-numeric: tabular-nums;
  color: #94a3b8;
  min-width: 2.5rem;
  text-align: left;
}

.legend {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 12px 18px;
  font-size: 0.85rem;
  color: #cbd5e1;
  margin-top: 2px;
  width: 100%;
}

.swatch {
  display: inline-block;
  width: 12px;
  height: 12px;
  border-radius: 2px;
  margin-right: 6px;
  vertical-align: middle;
}

.swatch.incident {
  background: #38bdf8;
}

.swatch.reflected {
  background: #fb923c;
}

.swatch.transmitted {
  background: #4ade80;
}

.swatch.prob {
  background: rgba(167, 139, 250, 0.6);
  border: 1px solid #a78bfa;
}

.theory-panel {
  background: rgba(15, 23, 42, 0.65);
  border: 1px solid #334155;
  border-radius: 10px;
  padding: 0.65rem 0.85rem 1.1rem;
  box-shadow: 0 1px 0 rgba(255, 255, 255, 0.04) inset;
  text-align: left;
}

@media (min-width: 1101px) {
  .theory-panel {
    position: sticky;
    top: 10px;
    max-height: calc(100vh - 20px);
    overflow-y: auto;
    -webkit-overflow-scrolling: touch;
  }
}

.theory-panel-title {
  font-size: 0.95rem;
  font-weight: 600;
  color: #38bdf8;
  margin: 0 0 0.55rem;
  line-height: 1.3;
}

.theory-panel p {
  margin: 0 0 0.85rem;
  font-size: 0.92rem;
  line-height: 1.55;
  color: #cbd5e1;
}

.theory-panel p:last-child {
  margin-bottom: 0;
}

.theory-panel strong {
  color: #e2e8f0;
  font-weight: 600;
}

.theory-panel em {
  color: #94a3b8;
  font-style: italic;
}

.theory-note {
  font-size: 0.85rem !important;
  color: #94a3b8 !important;
  border-top: 1px solid #1e293b;
  padding-top: 0.85rem !important;
  margin-top: 0.35rem !important;
}

.math-block {
  margin: 0.55rem 0 0.85rem;
  padding: 0.65rem 0.75rem;
  background: rgba(2, 6, 23, 0.55);
  border: 1px solid #1e293b;
  border-radius: 8px;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}

.math-block--multiline {
  overflow-x: visible;
}

.math-block--multiline .katex-display {
  overflow-x: visible;
}

.math-block-caption {
  margin: 0.5rem 0 0 !important;
  font-size: 0.82rem !important;
  color: #94a3b8 !important;
  text-align: center;
  line-height: 1.4;
}

.math-block--compact .katex {
  font-size: 0.88em;
}

.theory .katex {
  color: #f1f5f9;
}

.theory .katex-display {
  margin: 0.35rem 0 0;
}

.theory .katex-display > .katex {
  color: #e2e8f0;
}

@media (max-width: 1180px) {
  .main-layout {
    grid-template-columns: 1fr;
    grid-template-areas:
      "sim"
      "left"
      "right";
    gap: 1.1rem;
    max-width: min(42rem, 100%);
  }

  .sim-column {
    max-width: min(800px, 100%);
  }

  .theory-panel {
    position: static;
    max-height: none;
    overflow-y: visible;
  }
}

@media (max-width: 480px) {
  .page-header {
    padding-left: 0.75rem;
    padding-right: 0.75rem;
  }

  .theory-eyebrow {
    font-size: 0.82rem;
  }

  .controls label {
    flex-wrap: wrap;
    justify-content: center;
  }

  .mode-text {
    font-size: 0.9rem;
  }

  .theory-panel p {
    font-size: 0.88rem;
  }
}