:root {
  --bg: #f2efe8;
  --panel: rgba(255, 252, 246, 0.94);
  --panel-border: rgba(41, 57, 51, 0.14);
  --text: #1f2a2a;
  --muted: #58656a;
  --accent: #145c46;
  --accent-strong: #0c3f31;
  --danger: #a03030;
  --red: #d1495b;
  --green: #2c7a55;
  --blue: #2f6db5;
  --mirror: rgba(173, 181, 189, 0.9);
  --shadow: 0 18px 40px rgba(28, 35, 33, 0.12);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: Arial, Helvetica, sans-serif;
  color: var(--text);
  background:
    radial-gradient(circle at top left, rgba(20, 92, 70, 0.12), transparent 28%),
    radial-gradient(circle at bottom right, rgba(47, 109, 181, 0.1), transparent 22%),
    linear-gradient(180deg, #f8f4ed 0%, var(--bg) 100%);
}

.shell {
  display: grid;
  grid-template-columns: minmax(280px, 330px) minmax(0, 1fr);
  grid-template-areas:
    "controls viewer"
    "metrics viewer";
  align-items: start;
  gap: 16px;
  padding: 14px;
  min-height: 100vh;
}

.explainer-shell {
  padding: 0 14px 24px;
}

.explainer-card {
  max-width: 1280px;
  margin: 0 auto;
  padding: 24px 26px 28px;
  background: var(--panel);
  border: 1px solid rgba(41, 57, 51, 0.1);
  border-radius: 18px;
  box-shadow: 0 12px 26px rgba(28, 35, 33, 0.09);
  backdrop-filter: blur(10px);
}

.explainer-header {
  margin-bottom: 18px;
}

.explainer-eyebrow {
  margin: 0 0 6px;
  color: var(--accent);
  font-size: 0.82rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.explainer-header h2 {
  margin: 0;
  font-size: clamp(1.5rem, 2.8vw, 2rem);
  line-height: 1.15;
}

.explainer-content {
  max-width: none;
  width: 100%;
}

.explainer-content h3 {
  margin: 0 0 14px;
  font-size: 1.28rem;
  line-height: 1.2;
  letter-spacing: 0.01em;
}

.explainer-content p,
.explainer-loading {
  margin: 0 0 14px;
  color: var(--text);
  line-height: 1.7;
}

.explainer-content .katex-display {
  max-width: 100%;
  margin: 0.9em 0;
}

.equation-multiline {
  display: none;
}

.equation-single .katex-display {
  overflow-x: visible;
  overflow-y: hidden;
}

.explainer-matrix-block {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 12px;
  margin: 6px 0 22px;
  padding: 4px 0;
  border-radius: 0;
  background: transparent;
  border: 0;
  width: fit-content;
  max-width: 100%;
  margin-left: auto;
  margin-right: auto;
  --matrix-col-width: 40px;
  --matrix-col-gap: 12px;
}

.explainer-matrix-name {
  font-size: 1rem;
  font-weight: 600;
  color: var(--accent-strong);
  white-space: nowrap;
}

.explainer-matrix-group {
  display: grid;
  gap: 6px;
}

.explainer-matrix-label-row {
  display: flex;
  align-items: center;
  gap: 12px;
}

.explainer-matrix-label-offset {
  display: flex;
  padding-left: 20px;
}

.explainer-matrix-main {
  display: flex;
  align-items: center;
  gap: 12px;
}

.explainer-matrix-column-labels {
  display: grid;
  grid-template-columns: repeat(2, var(--matrix-col-width));
  gap: var(--matrix-col-gap);
  justify-items: center;
}

.explainer-column-label {
  width: var(--matrix-col-width);
  min-width: 0;
  padding: 3px 0;
  border-radius: 999px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  line-height: 1;
  text-align: center;
}

.explainer-column-a1 {
  color: var(--red);
  background: rgba(209, 73, 91, 0.12);
}

.explainer-column-a2 {
  color: var(--green);
  background: rgba(44, 122, 85, 0.12);
}

.explainer-matrix-name-spacer {
  visibility: hidden;
}

.explainer-matrix-shell {
  display: flex;
  align-items: stretch;
  gap: 10px;
}

.explainer-matrix-bracket {
  width: 10px;
  min-height: 64px;
  border-top: 2px solid rgba(31, 42, 42, 0.62);
  border-bottom: 2px solid rgba(31, 42, 42, 0.62);
}

.explainer-matrix-bracket.left {
  border-left: 2px solid rgba(31, 42, 42, 0.62);
}

.explainer-matrix-bracket.right {
  border-right: 2px solid rgba(31, 42, 42, 0.62);
}

.explainer-matrix-grid {
  display: grid;
  gap: 8px;
  padding: 2px 0;
  width: calc((2 * var(--matrix-col-width)) + var(--matrix-col-gap));
}

.explainer-matrix-row {
  display: grid;
  grid-template-columns: repeat(2, var(--matrix-col-width));
  gap: var(--matrix-col-gap);
  justify-items: center;
}

.explainer-matrix-entry {
  width: var(--matrix-col-width);
  min-width: 0;
  min-height: 22px;
  padding: 2px 0;
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  font: 0.98rem/1.15 "Cascadia Code", Consolas, monospace;
  line-height: 1;
  text-align: center;
}

.explainer-matrix-entry-a1 {
  color: var(--red);
  background: rgba(209, 73, 91, 0.08);
}

.explainer-matrix-entry-a2 {
  color: var(--green);
  background: rgba(44, 122, 85, 0.08);
}

.explainer-code {
  margin: 0 0 18px;
  padding: 14px 16px;
  overflow-x: auto;
  border-radius: 14px;
  border: 1px solid rgba(41, 57, 51, 0.09);
  background: rgba(31, 42, 42, 0.05);
  color: var(--text);
  font: 0.95rem/1.55 "Cascadia Code", Consolas, monospace;
}

.explainer-figure {
  margin: 8px 0 22px;
  text-align: center;
}

.explainer-figure svg,
.explainer-figure img {
  display: block;
  width: 100%;
  max-width: 500px;
  height: auto;
  border-radius: 22px;
  border: 1px solid rgba(41, 57, 51, 0.08);
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.7);
  background: rgba(255, 255, 255, 0.88);
  margin: 0 auto;
}

.explainer-figure figcaption {
  margin-top: 10px;
  color: var(--muted);
  font-size: 0.94rem;
  line-height: 1.5;
}

.orientation-matrix-row,
.orientation-plot-row {
  display: flex;
  flex-wrap: nowrap;
  justify-content: center;
  gap: 8px;
  align-items: start;
}

.orientation-plot-row {
  justify-content: space-evenly;
}

.orientation-matrix-row {
  justify-content: space-evenly;
}

.orientation-matrix-row {
  margin: 8px 0 22px;
}

.orientation-plot-row {
  margin: 0 0 22px;
}

.orientation-matrix-block {
  --matrix-col-width: 32px;
  --matrix-col-gap: 8px;
  margin: 0;
  justify-self: center;
  transform: scale(0.9);
  transform-origin: center;
}

.orientation-matrix-row > .orientation-matrix-block,
.orientation-plot-row > .orientation-figure {
  flex: 0 0 346px;
}

.orientation-matrix-row > .orientation-matrix-block {
  display: flex;
  justify-content: center;
}

.orientation-figure {
  width: 100%;
}

.orientation-figure svg,
.orientation-figure img {
  max-width: 346px;
}

.orientation-plot-row > .orientation-figure {
  margin: 0;
}

.orientation-matrix-block .explainer-matrix-main {
  gap: 8px;
}

.orientation-matrix-block .explainer-matrix-label-row {
  gap: 8px;
}

.orientation-matrix-block .explainer-matrix-column-labels {
}

.orientation-matrix-block .explainer-matrix-label-offset {
  padding-left: 18px;
}


.panel {
  background: var(--panel);
  border: 1px solid rgba(41, 57, 51, 0.1);
  border-radius: 18px;
  box-shadow: 0 12px 26px rgba(28, 35, 33, 0.09);
  backdrop-filter: blur(10px);
}

.site-footer {
  margin-top: 12px;
  padding: 10px 14px 16px;
  text-align: center;
}

.site-footer a {
  display: inline-block;
  padding: 8px 14px;
  border-radius: 999px;
  background: rgba(255, 252, 246, 0.94);
  border: 1px solid rgba(41, 57, 51, 0.1);
  color: var(--muted);
  font-size: 0.84rem;
  line-height: 1;
  text-decoration: none;
  box-shadow: 0 8px 18px rgba(28, 35, 33, 0.06);
}

.site-footer a:hover {
  color: var(--accent-strong);
}

.controls {
  grid-area: controls;
  display: flex;
  flex-direction: column;
  align-self: start;
  gap: 12px;
  padding: 16px;
}

.metrics-panel {
  grid-area: metrics;
  align-self: start;
  padding: 16px;
}

.panel-header h1,
.matrix-header h2 {
  margin: 0;
  font-weight: 600;
  letter-spacing: 0.03em;
}

.panel-header {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 12px;
}

.panel-header h1 {
  font-size: 1.3rem;
  text-transform: lowercase;
}

.title-link {
  color: inherit;
  text-decoration: none;
}

.title-link:hover {
  text-decoration: none;
}

.panel-header p {
  margin: 0;
  max-width: 18rem;
  font-size: 0.84rem;
  line-height: 1.35;
}

.panel-header p,
.status-label {
  color: var(--muted);
}

.formula {
  margin: 0;
  text-align: center;
}

.formula .katex {
  font-size: 1.3em;
}

.panel-header p,
.hint,
.status-row,
.legend,
button,
input {
  font-size: 0.98rem;
}

.matrix-card,
.status-card {
  display: flex;
  flex-direction: column;
  gap: 10px;
  padding: 12px;
  background: rgba(255, 255, 255, 0.56);
  border: 1px solid rgba(41, 57, 51, 0.06);
  border-radius: 14px;
}

.matrix-header,
.matrix-actions,
.transport,
.status-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
}

.matrix-actions {
  justify-content: flex-end;
  flex-wrap: wrap;
}

.matrix-actions-centered {
  justify-content: center;
}

.panel-action {
  display: flex;
  justify-content: center;
}

.panel-action button {
  width: 100%;
}

.matrix-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 8px;
}

.matrix-column-labels {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 8px;
}

.column-label {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 6px 8px;
  border-radius: 8px;
  font-size: 0.92rem;
  font-weight: 600;
}

.column-a1 {
  background: rgba(209, 73, 91, 0.12);
  color: var(--red);
}

.column-a2 {
  background: rgba(44, 122, 85, 0.12);
  color: var(--green);
}

.column-a3 {
  background: rgba(47, 109, 181, 0.12);
  color: var(--blue);
}

input {
  width: 100%;
  padding: 10px 9px;
  border-radius: 10px;
  border: 1px solid rgba(31, 42, 42, 0.16);
  background: rgba(255, 255, 255, 0.88);
  color: var(--text);
  appearance: textfield;
  -moz-appearance: textfield;
  text-align: center;
}

input::-webkit-outer-spin-button,
input::-webkit-inner-spin-button {
  -webkit-appearance: none;
  margin: 0;
}

.matrix-input-a1 {
  background: rgba(209, 73, 91, 0.08);
  border-color: rgba(209, 73, 91, 0.18);
}

.matrix-input-a2 {
  background: rgba(44, 122, 85, 0.08);
  border-color: rgba(44, 122, 85, 0.18);
}

.matrix-input-a3 {
  background: rgba(47, 109, 181, 0.08);
  border-color: rgba(47, 109, 181, 0.18);
}

input:focus {
  outline: 2px solid rgba(20, 92, 70, 0.22);
  border-color: var(--accent);
}

button {
  border: 0;
  border-radius: 999px;
  padding: 9px 13px;
  background: var(--accent);
  color: #f9faf7;
  cursor: pointer;
  transition: transform 140ms ease, background 140ms ease, opacity 140ms ease;
}

button:hover {
  background: var(--accent-strong);
  transform: translateY(-1px);
}

button:disabled {
  opacity: 0.45;
  cursor: not-allowed;
  transform: none;
}

.status-value {
  font-variant-numeric: tabular-nums;
  font-size: 1.05rem;
  font-weight: 600;
}

.message-row {
  align-items: center;
}

#step-message {
  text-align: right;
  margin-left: auto;
}

.lengths-value {
  font-size: 0.96rem;
  white-space: nowrap;
}

.step-card {
  margin-top: 2px;
}

.transport {
  justify-content: stretch;
}

.transport button {
  flex: 1 1 0;
}

.legend {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 8px;
}

.legend div {
  display: flex;
  align-items: center;
  gap: 8px;
}

.legend-swatch {
  width: 14px;
  height: 14px;
  border-radius: 999px;
  display: inline-block;
}

.legend-swatch.red { background: var(--red); }
.legend-swatch.green { background: var(--green); }
.legend-swatch.blue { background: var(--blue); }
.legend-swatch.mirror { background: var(--mirror); }

.viewer-panel {
  grid-area: viewer;
  display: flex;
  flex-direction: column;
  align-self: stretch;
  min-height: calc(100vh - 28px);
  overflow: hidden;
}

.viewer {
  position: relative;
  flex: 1 1 auto;
  min-height: 560px;
  padding: 8px;
}

.viewer canvas {
  display: block;
  width: 100%;
  height: 100%;
  border-radius: 16px;
}

.label-layer {
  position: absolute;
  inset: 0;
  pointer-events: none;
}

.viewer-controls {
  position: absolute;
  top: 18px;
  right: 18px;
  z-index: 2;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.viewer-controls button {
  min-width: 34px;
  min-height: 30px;
  padding: 5px 8px;
  background: rgba(255, 252, 246, 0.9);
  color: var(--text);
  border: 1px solid rgba(41, 57, 51, 0.12);
  box-shadow: 0 6px 16px rgba(28, 35, 33, 0.1);
  border-radius: 6px;
  font-size: 0.95rem;
  line-height: 1;
}

.viewer-controls button:hover {
  background: rgba(255, 252, 246, 1);
}

.zoom-control {
  display: flex;
  flex-direction: column;
  overflow: hidden;
  border-radius: 6px;
  box-shadow: 0 6px 16px rgba(28, 35, 33, 0.1);
}

.zoom-control button {
  border-radius: 0;
  box-shadow: none;
  min-width: 34px;
}

.zoom-control button + button {
  border-top: 0;
}

.icon-button {
  font-size: 0.9rem;
}

.icon-button svg {
  width: 16px;
  height: 16px;
  display: block;
  stroke: currentColor;
  stroke-width: 1.8;
  stroke-linecap: round;
  stroke-linejoin: round;
  fill: none;
}

.scene-label {
  position: absolute;
  transform: translate(-50%, -50%);
  padding: 0;
  border-radius: 0;
  background: transparent;
  border: 0;
  box-shadow: none;
  font-size: 0.94rem;
  line-height: 1;
  white-space: nowrap;
  text-shadow: 0 0 4px rgba(255, 252, 246, 0.95);
}

.scene-label.axis {
  color: var(--muted);
}

.scene-label.vector-red {
  color: var(--red);
}

.scene-label.vector-green {
  color: var(--green);
}

.scene-label.vector-blue {
  color: var(--blue);
}

@media (max-width: 960px) {
  .shell {
    grid-template-columns: 1fr;
    grid-template-areas:
      "controls"
      "viewer"
      "metrics";
    height: auto;
    min-height: auto;
  }

  .viewer-panel {
    min-height: 0;
  }

  .viewer {
    min-height: clamp(260px, 40vh, 360px);
    padding: 0;
  }

  .panel-header {
    justify-content: center;
  }
}

@media (max-width: 1000px) and (min-width: 641px) {
  .viewer-panel {
    min-height: clamp(320px, 52vh, 440px);
  }

  .viewer {
    min-height: clamp(320px, 52vh, 440px);
  }

  .explainer-card {
    padding-left: 18px;
    padding-right: 18px;
  }

  .explainer-content .katex-display {
    font-size: 0.92em;
  }

  .orientation-matrix-row,
  .orientation-plot-row {
    gap: 6px;
  }

  .orientation-matrix-row > .orientation-matrix-block,
  .orientation-plot-row > .orientation-figure {
    flex: 1 1 0;
    min-width: 0;
  }

  .orientation-figure svg,
  .orientation-figure img {
    max-width: min(100%, 300px);
  }

  .orientation-matrix-block {
    transform: scale(0.82);
  }
}

@media (max-width: 640px) {
  .shell {
    padding: 12px;
    gap: 12px;
  }

  .controls {
    padding: 18px;
  }

  .metrics-panel {
    padding: 18px;
  }

  .matrix-header,
  .status-row,
  .viewer-controls {
    align-items: flex-start;
  }

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

  .viewer {
    min-height: clamp(264px, 40.8vh, 336px);
  }

  .viewer-panel {
    min-height: 0;
  }

  .explainer-shell {
    padding: 0 12px 20px;
  }

  .explainer-card {
    padding: 20px 18px 22px;
  }

  .explainer-matrix-block {
    flex-direction: column;
    align-items: center;
    gap: 12px;
    width: fit-content;
  }

  .explainer-matrix-shell {
    gap: 10px;
  }

  .explainer-matrix-grid {
    min-width: 0;
  }

  .orientation-matrix-row,
  .orientation-plot-row {
    display: grid;
    grid-template-columns: 1fr;
    gap: 18px;
  }

  .equation-single {
    display: none;
  }

  .equation-multiline {
    display: block;
  }
}

@media (max-width: 339px) {
  .equation-single {
    display: block;
  }

  .equation-multiline {
    display: none;
  }

  .equation-single .katex-display {
    overflow-x: auto;
    overflow-y: hidden;
    padding-bottom: 2px;
  }
}