:root {
  color-scheme: light;
  --bg: #f8faf8;
  --panel: #fffefe;
  --panel-2: #eef7f4;
  --text: #2f3440;
  --muted: #66717c;
  --line: #dde7e3;
  --accent: #d1495b;
  --accent-2: #2a9d8f;
  --blue: #247ba0;
  --jp-font: "Hiragino Kaku Gothic ProN", "Hiragino Sans", "Yu Gothic", "Meiryo", "Segoe UI", system-ui, sans-serif;
  --math-font: "Neo Euler", "Euler Math", "Euler", "Latin Modern Math", "Cambria Math", "Times New Roman", serif;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  background:
    radial-gradient(circle at 14% 12%, rgba(209, 73, 91, 0.12), transparent 28%),
    radial-gradient(circle at 82% 18%, rgba(42, 157, 143, 0.16), transparent 30%),
    linear-gradient(135deg, #f8faf8 0%, #f7fbff 48%, #fffdf6 100%);
  color: var(--text);
  font-family: var(--jp-font);
}

button,
input {
  font: inherit;
}

.hidden {
  display: none !important;
}

.level-select {
  display: grid;
  grid-template-columns: minmax(280px, 0.78fr) minmax(420px, 1.22fr);
  gap: 32px;
  width: min(1120px, calc(100vw - 40px));
  min-height: 100vh;
  margin: 0 auto;
  align-items: center;
}

.intro h1 {
  margin: 8px 0 0;
  font-size: clamp(36px, 5vw, 72px);
  line-height: 1.02;
  letter-spacing: 0;
}

.intro p {
  color: var(--muted);
  line-height: 1.8;
  max-width: 34rem;
}

.eyebrow {
  margin: 0;
  color: var(--accent);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.level-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 12px;
}

.level-card {
  min-height: 76px;
  padding: 18px 24px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: linear-gradient(145deg, rgba(255, 254, 254, 0.98), rgba(242, 251, 251, 0.94));
  color: var(--text);
  text-align: left;
  cursor: pointer;
  box-shadow: 0 16px 42px rgba(118, 154, 166, 0.12);
  transition: transform 140ms ease, border-color 140ms ease, background 140ms ease, box-shadow 140ms ease;
}

.level-card:hover {
  transform: translateY(-2px);
  border-color: var(--accent);
  background: var(--panel-2);
  box-shadow: 0 18px 48px rgba(118, 154, 166, 0.2);
}

.level-card span,
.level-card small {
  display: block;
  color: var(--muted);
}

.level-card span {
  color: var(--text);
  font-size: 24px;
  font-weight: 800;
}

.level-card strong {
  display: block;
  margin: 8px 0 6px;
  font-size: 24px;
}

.viewer {
  min-height: 100vh;
  padding: 8px 10px;
  overflow-x: auto;
}

.toolbar {
  display: flex;
  align-items: center;
  gap: 10px;
  min-width: 920px;
  min-height: 48px;
  padding: 6px 9px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: rgba(255, 254, 254, 0.96);
  box-shadow: 0 14px 36px rgba(118, 154, 166, 0.1);
}

.toolbar h2 {
  margin: 2px 0 0;
  font-size: 19px;
}

.title-controls {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 10px;
}

.math {
  font-family: var(--math-font);
  font-style: normal;
  letter-spacing: 0;
  white-space: nowrap;
}

.math sup {
  font-size: 0.72em;
  line-height: 0;
}

.toolbar-spacer {
  flex: 1;
}

.icon-button {
  width: 34px;
  height: 34px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--panel-2);
  color: var(--text);
  cursor: pointer;
}

.icon-button:hover {
  border-color: var(--accent);
  color: var(--accent);
}

.toggle {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  min-height: 40px;
  padding: 0 12px;
  border: 1px solid var(--line);
  border-radius: 8px;
  color: var(--muted);
  background: #fffafd;
  cursor: pointer;
  white-space: nowrap;
}

.toggle input {
  accent-color: var(--accent);
}

.coeff-controls {
  display: flex;
  flex-wrap: wrap;
  justify-content: flex-end;
  gap: 6px;
}

.tiny-toggle,
.normalize-inline {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  min-height: 24px;
  padding: 2px 7px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: rgba(255, 250, 253, 0.92);
  color: var(--muted);
  font-size: 12px;
  font-weight: 700;
  cursor: pointer;
  white-space: nowrap;
}

.tiny-toggle input,
.normalize-inline input {
  width: 13px;
  height: 13px;
  margin: 0;
  accent-color: var(--accent);
}

.slider-panel {
  display: grid;
  grid-template-columns: auto minmax(260px, 520px) 90px;
  align-items: center;
  gap: 14px;
  min-width: 920px;
  margin-top: 8px;
  padding: 8px 12px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: rgba(255, 254, 254, 0.96);
}

.slider-panel label {
  color: var(--muted);
  font-weight: 700;
}

.slider-panel input {
  width: 100%;
  accent-color: var(--accent);
}

.slider-panel output {
  font-variant-numeric: tabular-nums;
  color: var(--accent);
}

.number-panel {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 4px 14px;
  padding: 5px 9px;
  background: rgba(255, 254, 254, 0.96);
}

.number-panel .normalize-inline {
  display: inline-flex;
  grid-template-columns: none;
  grid-column: 1 / -1;
  justify-self: start;
  width: auto;
  margin-bottom: 2px;
}

.number-panel .normalize-inline input {
  width: 13px;
  min-height: 13px;
  padding: 0;
  border: 0;
}

.number-panel label {
  display: grid;
  grid-template-columns: 16px 50px minmax(130px, 1fr);
  align-items: center;
  gap: 5px;
  color: var(--muted);
  font-size: 12px;
  font-weight: 700;
}

.number-panel input {
  width: 100%;
  min-height: 23px;
  border: 1px solid var(--line);
  border-radius: 6px;
  padding: 0 7px;
  background: #fffafd;
  color: var(--text);
  font-variant-numeric: tabular-nums;
}

.number-panel input[type="number"] {
  appearance: textfield;
  -moz-appearance: textfield;
}

.number-panel input[type="number"]::-webkit-inner-spin-button,
.number-panel input[type="number"]::-webkit-outer-spin-button {
  margin: 0;
  appearance: none;
  -webkit-appearance: none;
}

.number-panel input[type="range"] {
  min-height: 18px;
  padding: 0;
  border: 0;
  background: transparent;
  accent-color: var(--accent);
}

.number-panel label.normalize-inline {
  display: inline-flex;
  grid-template-columns: none;
  width: auto;
  min-height: 24px;
}

.number-panel label.normalize-inline input {
  width: 13px;
  height: 13px;
  min-height: 13px;
  padding: 0;
  border: 0;
}

.panes {
  display: grid;
  grid-template-columns: minmax(440px, 1fr) minmax(440px, 1fr);
  gap: 10px;
  min-width: 920px;
  margin-top: 8px;
}

.pane {
  min-width: 0;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: rgba(255, 254, 254, 0.96);
  box-shadow: 0 18px 52px rgba(118, 154, 166, 0.1);
  overflow: hidden;
}

.pane-title {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 7px 10px 5px;
}

.pane-title h3 {
  margin: 0;
  font-size: 17px;
}

.pane-title p {
  display: none;
  margin: 0;
  color: var(--muted);
  font-variant-numeric: tabular-nums;
}

#root-summary {
  display: none;
}

canvas {
  display: block;
  width: 100%;
  height: clamp(360px, calc(100vh - 168px), 560px);
  min-height: 360px;
  background: linear-gradient(180deg, #fffafd 0%, #fffefe 100%);
  cursor: crosshair;
}

#coeff-canvas {
  touch-action: none;
}

#graph-canvas {
  width: min(100%, 560px);
  margin: 0 auto;
}

.coeff-canvas-wrap {
  position: relative;
}

.spatial-drag-toggle {
  position: absolute;
  right: 8px;
  bottom: 8px;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  min-height: 24px;
  padding: 2px 7px;
  border: 1px solid rgba(221, 231, 227, 0.92);
  border-radius: 6px;
  background: rgba(255, 254, 254, 0.9);
  color: var(--muted);
  font-size: 12px;
  font-weight: 700;
  cursor: pointer;
  box-shadow: 0 8px 20px rgba(60, 73, 82, 0.08);
}

.spatial-drag-toggle input {
  width: 13px;
  height: 13px;
  margin: 0;
  accent-color: var(--accent);
}

.hint {
  margin: 0;
  padding: 6px 12px 8px;
  color: var(--muted);
  font-size: 13px;
}

.solution-badge {
  min-height: 40px;
  padding: 8px 11px;
  border-top: 1px solid var(--line);
  color: var(--text);
  background: #fff9f0;
  font-weight: 700;
  font-size: 15px;
  line-height: 1.45;
  white-space: pre-line;
}

@media (max-width: 900px) {
  .level-select {
    grid-template-columns: 1fr;
    padding: 28px 0;
  }

  .toolbar {
    flex-wrap: wrap;
  }
}

@media (max-width: 700px) {
  body {
    overflow-x: hidden;
  }

  .viewer {
    padding: 6px;
    overflow-x: hidden;
  }

  .toolbar {
    min-width: 0;
    min-height: 44px;
    gap: 8px;
    padding: 6px 8px;
  }

  .toolbar h2 {
    font-size: 15px;
    line-height: 1.25;
  }

  .eyebrow {
    font-size: 10px;
  }

  .icon-button {
    width: 32px;
    height: 32px;
    flex: 0 0 auto;
  }

  .slider-panel {
    min-width: 0;
    grid-template-columns: auto minmax(0, 1fr) auto;
    gap: 8px;
    margin-top: 6px;
    padding: 6px 8px;
  }

  .panes {
    min-width: 0;
    grid-template-columns: minmax(0, 1fr);
    gap: 8px;
    margin-top: 6px;
  }

  .pane {
    border-radius: 6px;
  }

  .pane-title {
    align-items: flex-start;
    flex-wrap: wrap;
    gap: 4px;
    padding: 6px 6px 4px;
  }

  .pane-title h3 {
    font-size: 14px;
    line-height: 1.25;
  }

  .coeff-controls {
    justify-content: flex-start;
    gap: 3px;
  }

  .tiny-toggle,
  .normalize-inline,
  .spatial-drag-toggle {
    min-height: 20px;
    gap: 4px;
    padding: 1px 4px;
    border-radius: 5px;
    font-size: 10px;
  }

  .tiny-toggle input,
  .normalize-inline input,
  .spatial-drag-toggle input,
  .number-panel label.normalize-inline input {
    width: 11px;
    height: 11px;
    min-height: 11px;
  }

  canvas {
    height: min(40vh, 360px);
    min-height: 260px;
  }

  #graph-canvas {
    width: 100%;
  }

  .number-panel {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 3px 10px;
    padding: 4px 5px;
  }

  .number-panel label {
    grid-template-columns: 12px 44px minmax(0, 1fr);
    gap: 3px;
    font-size: 11px;
  }

  .number-panel input {
    min-height: 22px;
    padding: 0 4px;
    border-radius: 5px;
  }

  .number-panel input[type="range"] {
    min-height: 16px;
  }

  .number-panel label.normalize-inline {
    min-height: 20px;
  }

  .solution-badge {
    min-height: 34px;
    padding: 6px 8px;
    font-size: 13px;
    line-height: 1.35;
  }

  .spatial-drag-toggle {
    right: 5px;
    bottom: 5px;
  }
}

@media (max-width: 420px) {
  .toolbar h2 {
    font-size: 14px;
  }

  .panes {
    gap: 7px;
  }

  canvas {
    height: 36vh;
    min-height: 240px;
  }

  .number-panel label {
    grid-template-columns: 12px 40px minmax(0, 1fr);
  }
}

@media (max-width: 340px) {
  .number-panel {
    grid-template-columns: minmax(0, 1fr);
  }
}