:root {
  --ink: #1f2933;
  --paper: #f7f5ef;
  --water-deep: #1d6f8c;
  --water-light: #cfe8ee;
  --accent: #e2a33b;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  background: var(--paper);
  color: var(--ink);
  font-family: "Hiragino Sans", "Yu Gothic", system-ui, sans-serif;
  line-height: 1.6;
}

.app-header {
  padding: 20px 24px 20px;
  text-align: center;
  background: linear-gradient(180deg, var(--water-light), transparent);
}

.header-nav {
  max-width: 720px;
  margin: 0 auto 10px;
  display: flex;
  justify-content: flex-start;
}

.home-btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 5px 14px;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--water-deep);
  text-decoration: none;
  background: rgba(255, 255, 255, 0.85);
  border: 1px solid rgba(29, 111, 140, 0.25);
  border-radius: 999px;
  transition: all 0.2s ease;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.05);
}

.home-btn:hover {
  background: #ffffff;
  border-color: var(--water-deep);
  transform: translateX(-2px);
}

.app-header h1 {
  margin: 0 0 8px;
  font-size: clamp(1.6rem, 4vw, 2.2rem);
  color: var(--water-deep);
}

.tagline {
  margin: 0;
  color: #4a5560;
  font-size: 0.95rem;
}

#app-root {
  max-width: 720px;
  margin: 0 auto;
  padding: 24px;
}



.density-boxes {
  display: flex;
  flex-wrap: wrap;
  gap: 20px;
  justify-content: center;
  margin-top: 24px;
}

.density-figure {
  margin: 0;
  text-align: center;
}

.density-particle-outline {
  fill: none;
  stroke: #b9a877;
  stroke-width: 1;
  stroke-dasharray: 2 2;
}

.density-bar {
  display: block;
  margin: 8px auto 0;
}

.density-bar-track {
  fill: #e6ebee;
}

.density-bar-fill {
  fill: var(--accent);
}

.density-bar-tick {
  stroke: #ffffff;
  stroke-width: 1;
}

.density-bar-tick.major {
  stroke: #9aa5ad;
}

.density-bar-label {
  fill: #6b7680;
  font-size: 10px;
}

.density-figure figcaption .caption-main,
.density-figure figcaption .caption-detail {
  display: block;
}

.density-figure figcaption .caption-detail {
  font-size: 0.8rem;
  color: #6b7680;
}

.density-legend {
  margin: 0 0 16px;
  font-size: 0.85rem;
  color: #4a5560;
}

.legend-dot {
  display: inline-block;
  width: 10px;
  height: 10px;
  margin: 0 2px 0 4px;
  border-radius: 50%;
  background: var(--accent);
  vertical-align: baseline;
}

.legend-dot.coin {
  background: #e9edf0;
  border: 1px solid #8b97a1;
}

.legend-dot.part {
  background: transparent;
  border: 1px dashed #b9a877;
}

.density-material-placeholder {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 72px;
  height: 72px;
  margin: 0 auto 6px;
  border: 2px dashed #b7c0c7;
  border-radius: 12px;
  color: #9aa5ad;
  font-size: 2rem;
  font-weight: 700;
}

.density-material-img {
  display: block;
  width: 72px;
  height: 72px;
  margin: 0 auto 6px;
  object-fit: contain;
}

.density-box-border {
  fill: #ffffff;
  stroke: var(--water-deep);
  stroke-width: 2;
}

.density-coin {
  fill: #e9edf0;
  stroke: #8b97a1;
  stroke-width: 1.2;
}

.density-coin-ring {
  fill: none;
  stroke: #b8c1c8;
  stroke-width: 0.8;
}

.density-coin-mark {
  fill: #6b7680;
  font-weight: 700;
  text-anchor: middle;
}

.density-hatch-line {
  stroke: var(--accent);
  stroke-width: 2;
  stroke-linecap: round;
}

/* 表し方の切り替え(1円玉 / 斜線) */
:root:not([data-density-view="hatch"]) .view-hatch,
:root[data-density-view="hatch"] .view-coin {
  display: none;
}

.legend-hatch-text {
  display: none;
}

:root[data-density-view="hatch"] .legend-hatch-text {
  display: inline;
}

:root[data-density-view="hatch"] .legend-coin-text {
  display: none;
}

.view-switch {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 6px;
  margin-bottom: 8px;
  font-size: 0.9rem;
}

.view-btn {
  padding: 4px 12px;
  border: 1px solid var(--water-deep);
  border-radius: 999px;
  background: #fff;
  color: var(--water-deep);
  font-size: 0.85rem;
  cursor: pointer;
}

.view-btn[aria-pressed="true"] {
  background: var(--water-deep);
  color: #fff;
}

.legend-line {
  margin: 0 2px 0 4px;
  color: var(--accent);
  font-weight: 700;
}

.legend-line.part {
  opacity: 0.4;
}

.density-figure figcaption {
  margin-top: 8px;
  font-size: 0.85rem;
  color: #4a5560;
}

.interaction-section {
  margin-top: 40px;
  padding-top: 24px;
  border-top: 1px solid var(--water-light);
}

.interaction-section h2 {
  font-size: 1.2rem;
  color: var(--water-deep);
  margin-bottom: 16px;
}

.make-lead {
  margin: 0 0 12px;
  font-size: 0.95rem;
}

.material-picker {
  margin-bottom: 16px;
}

.material-picker-head {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 6px 12px;
  margin-bottom: 8px;
  font-size: 0.9rem;
}

.material-picker-label {
  font-weight: 600;
  color: var(--water-deep);
}

.material-bulk-btn {
  padding: 2px 10px;
  border: 1px solid #b7c0c7;
  border-radius: 999px;
  background: transparent;
  color: #6b7680;
  font-size: 0.8rem;
  cursor: pointer;
}

.material-bulk-btn:hover {
  background: #eef1f3;
}

.material-chips {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.material-chip-density {
  font-size: 0.8rem;
  color: #6b7680;
}

.material-chip {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 4px 12px 4px 6px;
  border: 2px solid var(--water-light);
  border-radius: 999px;
  background: #fff;
  color: var(--ink);
  font-size: 0.9rem;
  cursor: pointer;
}

.material-chip img {
  width: 32px;
  height: 32px;
  object-fit: contain;
}

.material-chip[aria-pressed="true"] {
  border-color: var(--water-deep);
  background: #e6f2f6;
}

.make-target {
  margin: 0 0 12px;
  font-weight: 600;
  color: var(--water-deep);
}

.make-feedback {
  min-height: 1.6em;
  margin: 0 0 8px;
  font-weight: 600;
}

.make-feedback.ok {
  color: #2f7d4f;
}

.make-feedback.near {
  color: #8a6a12;
}

.make-feedback.ng {
  color: #b5541c;
}

.make-hint {
  margin-bottom: 8px;
  font-size: 0.9rem;
  color: #4a5560;
}

.make-hint summary {
  cursor: pointer;
}

.make-hint p {
  margin: 6px 0 0;
}

.make-record {
  min-height: 1.4em;
  margin: 0 0 16px;
  font-size: 0.9rem;
  color: #2f7d4f;
  white-space: pre-line;
}

.make-viz {
  display: flex;
  flex-wrap: wrap;
  gap: 24px;
  justify-content: center;
}

.interaction-controls {
  margin-bottom: 16px;
  font-size: 0.95rem;
}

.interaction-controls select {
  margin-left: 8px;
  padding: 4px 8px;
  font-size: 0.95rem;
}

.interaction-sliders {
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin-bottom: 16px;
}

.slider-item {
  display: grid;
  grid-template-columns: 120px 1fr 70px;
  align-items: center;
  gap: 12px;
}

.slider-item input[type="range"] {
  width: 100%;
}

.slider-control {
  display: flex;
  align-items: center;
  gap: 6px;
  min-width: 0;
}

.slider-control input[type="range"] {
  flex: 1 1 auto;
  min-width: 0;
}

.step-btn {
  flex: 0 0 auto;
  width: 32px;
  height: 32px;
  padding: 0;
  border: 1px solid var(--water-deep);
  border-radius: 50%;
  background: #fff;
  color: var(--water-deep);
  font-size: 1.1rem;
  line-height: 1;
  cursor: pointer;
}

.step-btn:hover:not(:disabled) {
  background: #e6f2f6;
}

.step-btn:disabled {
  opacity: 0.35;
  cursor: default;
}

.slider-value {
  text-align: right;
  font-variant-numeric: tabular-nums;
}

.interaction-result {
  font-size: 1rem;
  font-weight: 600;
  color: var(--ink);
  margin-bottom: 16px;
}

.interaction-viz {
  display: flex;
  justify-content: center;
}

.section-note {
  margin: -8px 0 16px;
  font-size: 0.9rem;
  color: #4a5560;
}

.compare-volume-row {
  margin-bottom: 12px;
  font-size: 0.95rem;
}

.compare-volume-row input[type="range"] {
  width: 200px;
  margin: 0 8px;
  vertical-align: middle;
}

.compare-capacity-row {
  margin-bottom: 12px;
  font-size: 0.95rem;
}

.compare-capacity-row select {
  margin-left: 8px;
  padding: 4px 8px;
  font-size: 0.95rem;
}

.compare-capacity-note {
  margin-left: 8px;
  font-size: 0.85rem;
  color: #6b7680;
}

.sub-switch {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 6px;
  margin-bottom: 16px;
  font-size: 0.9rem;
}

.sub-btn {
  padding: 6px 14px;
  border: 1px solid var(--water-deep);
  border-radius: 999px;
  background: #fff;
  color: var(--water-deep);
  font-size: 0.9rem;
  cursor: pointer;
}

.sub-btn[aria-pressed="true"] {
  background: var(--water-deep);
  color: #fff;
}

.sub-panel h3 {
  margin: 0 0 8px;
  font-size: 1.05rem;
  color: var(--water-deep);
}

.samemass-plane-top {
  fill: #fff2cf;
}

.samemass-plane-frame {
  fill: none;
  stroke: #c98a1b;
  stroke-width: 2;
}

.samemass-grid {
  fill: none;
  stroke: #e2c98a;
  stroke-width: 1;
}

.samemass-plane-side {
  fill: var(--accent);
  stroke: #c98a1b;
  stroke-width: 1;
}

.samemass-height-label {
  fill: #6b7680;
  font-size: 10px;
  text-anchor: middle;
}

.samemass-ground {
  stroke: #b7c0c7;
  stroke-width: 1.5;
}

.compare-figure figcaption .samemass-ratio {
  color: #175d76;
  font-weight: 600;
}

.samemass-note {
  margin: 0 0 12px;
}

.compare-figure {
  margin: 0;
  text-align: center;
}

.compare-figure figcaption {
  margin-top: 4px;
  font-size: 0.9rem;
}

.compare-figure figcaption .caption-main,
.compare-figure figcaption .caption-detail {
  display: block;
}

.compare-figure figcaption .caption-main {
  font-weight: 600;
}

.compare-figure figcaption .caption-detail {
  font-size: 0.8rem;
  color: #6b7680;
}

.compare-figure figcaption .caption-detail.scale-over {
  color: #b5541c;
  font-weight: 600;
}

.spring-line,
.spring-ruler {
  stroke: #6b7680;
  stroke-width: 1.5;
}

.spring-housing {
  fill: #dfe6ea;
  stroke: #6b7680;
  stroke-width: 1.5;
}

.spring-coil {
  fill: none;
  stroke: #4a5560;
  stroke-width: 2;
  stroke-linejoin: round;
}

.spring-pointer {
  stroke: #d64545;
  stroke-width: 1.5;
  stroke-dasharray: 3 2;
}

.spring-tick-label {
  fill: #4a5560;
  font-size: 9px;
}

.compare-boxes {
  display: flex;
  flex-wrap: wrap;
  gap: 20px;
  justify-content: center;
}

.material-note {
  margin: 20px 0 0;
  font-size: 0.8rem;
  color: #6b7680;
  white-space: pre-line;
}

.compare-empty {
  color: #6b7680;
}

.float-controls {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 16px;
  font-size: 0.95rem;
}

.float-controls button {
  padding: 6px 14px;
  border: none;
  border-radius: 6px;
  background: var(--water-deep);
  color: #fff;
  font-size: 0.9rem;
  cursor: pointer;
}

.float-controls button:hover {
  background: #175d76;
}

.float-tank {
  position: relative;
  width: 100%;
  max-width: 640px;
  margin: 0 auto;
  background: linear-gradient(180deg, #eef6f8, #eef6f8);
  border: 2px solid var(--water-deep);
  border-radius: 8px;
  overflow: hidden;
}

.float-water {
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(29, 111, 140, 0.35);
}

.float-object {
  position: absolute;
  left: 50%;
  transform: translateX(-50%);
  object-fit: contain;
  filter: drop-shadow(0 2px 3px rgba(0, 0, 0, 0.25));
  transition: top 0.6s ease-in;
}

.float-labels {
  display: grid;
  max-width: 640px;
  margin: 4px auto 0;
  font-size: 0.75rem;
  color: #4a5560;
  text-align: center;
}

.float-labels span {
  word-break: break-all;
  padding: 0 1px;
}

.float-results {
  display: flex;
  flex-wrap: wrap;
  gap: 6px 16px;
  justify-content: center;
  margin: 12px 0 0;
  padding: 0;
  list-style: none;
  font-size: 0.9rem;
  color: var(--ink);
}

.float-results .float-up {
  color: #175d76;
}

.float-results .float-down {
  color: #6b4a1f;
}

.float-empty {
  color: #6b7680;
}

.problem-progress {
  margin: 0 0 12px;
  font-size: 0.9rem;
  color: #4a5560;
}

.problem-card {
  padding: 16px;
  background: #fff;
  border: 1px solid var(--water-light);
  border-radius: 8px;
}

.problem-text {
  margin: 0 0 16px;
  font-size: 1.05rem;
}

.problem-input-row {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
}

.problem-input {
  width: 110px;
  padding: 6px 8px;
  font-size: 1rem;
  border: 1px solid #b7c0c7;
  border-radius: 6px;
  font-variant-numeric: tabular-nums;
}

.problem-unit {
  min-width: 48px;
  font-size: 0.95rem;
}

.problem-card button,
.problem-result button {
  padding: 6px 14px;
  border: none;
  border-radius: 6px;
  background: var(--water-deep);
  color: #fff;
  font-size: 0.9rem;
  cursor: pointer;
}

.problem-card button:hover:not(:disabled),
.problem-result button:hover {
  background: #175d76;
}

.problem-card button:disabled {
  opacity: 0.45;
  cursor: default;
}

.problem-card button.secondary {
  background: #6b7680;
}

.problem-feedback {
  min-height: 1.6em;
  margin: 12px 0;
  font-weight: 600;
}

.problem-feedback.ok {
  color: #2f7d4f;
}

.problem-feedback.ng,
.problem-feedback.warn {
  color: #b5541c;
}

.problem-result {
  padding: 24px 16px;
  text-align: center;
  background: #fff;
  border: 1px solid var(--water-light);
  border-radius: 8px;
}

.problem-result-text {
  margin: 0 0 16px;
  font-size: 1.05rem;
  font-weight: 600;
}

.problem-hints {
  margin: 12px 0 0;
  padding: 8px 12px 8px 32px;
  background: #fff8e6;
  border-left: 4px solid var(--accent);
  border-radius: 4px;
  font-size: 0.92rem;
}

.problem-hints:empty {
  display: none;
}

.problem-hints li + li {
  margin-top: 6px;
}

.intro-section {
  margin-top: 0;
  padding-top: 0;
  border-top: none;
}

.problem-mastery {
  margin: 0 0 12px;
  font-size: 0.85rem;
  color: #4a5560;
}

.problem-footer {
  margin-top: 12px;
  text-align: right;
}

.problem-footer button {
  padding: 4px 10px;
  border: 1px solid #b7c0c7;
  border-radius: 6px;
  background: transparent;
  color: #6b7680;
  font-size: 0.8rem;
  cursor: pointer;
}

.problem-footer button:hover {
  background: #eef1f3;
}

/* ---- スマホ・タブレット向け ---- */
@media (max-width: 600px) {
  .app-header {
    padding: 24px 16px 16px;
  }

  #app-root {
    padding: 16px;
  }

  .interaction-section {
    margin-top: 32px;
  }

  .density-boxes,
  .compare-boxes {
    gap: 12px;
  }

  /* スライダー: ラベルと値を1行目、スライダー本体を2行目に */
  .slider-item {
    grid-template-columns: 1fr auto;
    grid-template-areas:
      "label value"
      "range range";
    gap: 4px 12px;
  }

  .slider-item label {
    grid-area: label;
  }

  .slider-item .slider-control {
    grid-area: range;
  }

  .slider-item .slider-value {
    grid-area: value;
  }

  .compare-volume-row label {
    display: block;
  }

  .compare-volume-row input[type="range"] {
    display: block;
    width: 100%;
    margin: 8px 0 0;
  }

  .float-controls {
    flex-wrap: wrap;
  }

  .problem-card {
    padding: 12px;
  }

  .problem-input-row {
    gap: 8px;
  }

  .problem-input {
    flex: 1 1 100px;
    min-width: 0;
  }
}

/* タッチ操作: 指で押しやすい大きさにし、入力欄でiOSが自動ズームしないよう16px以上にする */
@media (pointer: coarse) {
  button,
  select {
    min-height: 44px;
  }

  .step-btn {
    width: 44px;
  }

  select,
  input[type="text"] {
    font-size: 16px;
  }

  input[type="range"] {
    height: 32px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .float-object {
    transition: none;
  }
}

/* ---- タブ切り替え ---- */
[hidden] {
  display: none !important;
}

.tab-bar {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  gap: 4px;
  margin: 0 -24px 20px;
  padding: 0 24px;
  overflow-x: auto;
  background: var(--paper);
  border-bottom: 2px solid var(--water-light);
  scrollbar-width: none;
  -webkit-overflow-scrolling: touch;
}

.tab-bar::-webkit-scrollbar {
  display: none;
}

.tab {
  flex: 0 0 auto;
  margin-bottom: -2px;
  padding: 10px 14px;
  border: none;
  border-bottom: 3px solid transparent;
  background: transparent;
  color: #4a5560;
  font-size: 0.95rem;
  white-space: nowrap;
  cursor: pointer;
}

.tab:hover {
  color: var(--water-deep);
}

.tab[aria-selected="true"] {
  color: var(--water-deep);
  font-weight: 700;
  border-bottom-color: var(--water-deep);
}

.tab:focus-visible,
.tab-panel:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

.tab-panel {
  margin-top: 0;
  padding-top: 0;
  border-top: none;
}

@media (max-width: 600px) {
  .tab-bar {
    margin: 0 -16px 16px;
    padding: 0 16px;
  }

  .tab {
    padding: 10px 12px;
    font-size: 0.9rem;
  }
}

/* ---- スマホ用のタブ表示(◀ いまのタブ ▶ / js/tabPager.js) ---- */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  margin: -1px;
  padding: 0;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* 広い画面: 入れ物は無いものとして扱い、これまでどおり横にならべる */
.tab-pager,
.tab-pager-row {
  display: contents;
}

.tab-arrow,
.tab-pager-dots {
  display: none;
}

@keyframes tabSlideFromRight {
  from { transform: translateX(32px); opacity: 0; }
  to { transform: translateX(0); opacity: 1; }
}

@keyframes tabSlideFromLeft {
  from { transform: translateX(-32px); opacity: 0; }
  to { transform: translateX(0); opacity: 1; }
}

@media (max-width: 600px) {
  .tab-pager {
    display: block;
    position: sticky;
    top: 0;
    z-index: 10;
    margin: 0 -16px 16px;
    padding: 8px 16px 8px;
    background: var(--paper);
    border-bottom: 2px solid var(--water-light);
  }

  /* 帯(左右にスワイプできる) */
  .tab-pager-row {
    display: flex;
    align-items: center;
    height: 48px;
    padding: 0 2px;
    overflow: hidden;
    background: #fff;
    border: 2px solid var(--water-light);
    border-radius: 999px;
    touch-action: pan-y; /* たてスクロールはそのまま、よこの動きはこちらで受ける */
  }

  .tab-arrow {
    display: flex;
    align-items: center;
    justify-content: center;
    flex: 0 0 48px;
    width: 48px;
    height: 100%;
    padding: 0;
    border: none;
    background: transparent;
    color: var(--water-deep);
    font-size: 0.9rem;
    cursor: pointer;
    transition: transform 0.15s;
  }

  .tab-arrow:active {
    transform: scale(0.85);
  }

  .tab-arrow:focus-visible {
    outline: 2px solid var(--accent);
    outline-offset: -4px;
    border-radius: 999px;
  }

  /* タブの帯は、いま開いている1つだけを見せる */
  .tab-pager .tab-bar {
    position: static;
    flex: 1 1 auto;
    align-items: center;
    justify-content: center;
    min-width: 0;
    height: 100%;
    margin: 0;
    padding: 0;
    overflow: hidden;
    background: transparent;
    border-bottom: none;
  }

  .tab-pager .tab {
    display: none;
    margin: 0;
    padding: 0 8px;
    border-bottom: none;
    color: var(--water-deep);
    font-size: 1.05rem;
    font-weight: 700;
  }

  .tab-pager .tab[aria-selected="true"] {
    display: block;
  }

  .tab-pager .tab:focus-visible {
    outline-offset: -4px;
  }

  .tab-pager .tab.slide-from-right {
    animation: tabSlideFromRight 0.28s cubic-bezier(0.2, 0.8, 0.2, 1);
  }

  .tab-pager .tab.slide-from-left {
    animation: tabSlideFromLeft 0.28s cubic-bezier(0.2, 0.8, 0.2, 1);
  }

  /* 帯の下の点: 全部でいくつあって、いまどこかがわかる */
  .tab-pager-dots {
    display: flex;
    justify-content: center;
    gap: 6px;
    margin-top: 8px;
  }

  .tab-pager-dot {
    width: 6px;
    height: 6px;
    border-radius: 3px;
    background: var(--water-light);
    transition: width 0.2s, background-color 0.2s;
  }

  .tab-pager-dot.is-current {
    width: 18px;
    background: var(--water-deep);
  }
}

@media (prefers-reduced-motion: reduce) {
  .tab-pager .tab.slide-from-right,
  .tab-pager .tab.slide-from-left {
    animation: none;
  }
}

/* ---- 高学年向けの説明(ひらいて読む) ---- */
.upper-note {
  margin: 0 0 16px;
  padding: 8px 14px;
  background: #fff;
  border: 1px solid var(--water-light);
  border-left: 4px solid var(--accent);
  border-radius: 6px;
  font-size: 0.9rem;
  color: #4a5560;
}

.upper-note summary {
  padding: 6px 0;
  color: var(--water-deep);
  font-weight: 700;
  cursor: pointer;
}

.upper-note-body p {
  margin: 8px 0 0;
}

/* ---- 計算問題：数字キーパッド ---- */
.problem-card .pk-toggle {
  display: block;
  margin-top: 12px;
}

.problem-keypad {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 8px;
  max-width: 360px;
  margin: 12px 0 0;
}

.problem-keypad[hidden] {
  display: none;
}

.problem-card .pk-key {
  min-height: 52px;
  padding: 6px 0;
  background: #fff;
  color: var(--ink);
  border: 1px solid #b7c0c7;
  border-radius: 10px;
  font-size: 1.4rem;
  font-weight: 700;
  touch-action: manipulation;
}

.problem-card .pk-key:hover:not(:disabled) {
  background: var(--water-light);
}

.problem-card .pk-key:active:not(:disabled) {
  background: var(--water-light);
}

.problem-card .pk-key.pk-op {
  color: var(--water-deep);
}

.problem-card .pk-key.pk-wide {
  grid-column: 1 / -1;
  min-height: 44px;
  font-size: 0.95rem;
  color: #6b7680;
}

.problem-card .pk-key.pk-half {
  grid-column: span 2;
  min-height: 52px;
  font-size: 0.95rem;
  color: #6b7680;
}

.problem-card .pk-key.pk-eq {
  background: var(--water-deep);
  color: #fff;
  border-color: var(--water-deep);
}

.problem-card .pk-key.pk-eq:hover:not(:disabled) {
  background: #175d76;
}

/* 式も入力できるように、答えの欄を広げる */
.problem-input {
  width: auto;
  flex: 1 1 180px;
  min-width: 0;
}

/* ===== 国勢調査アプリ用の追加スタイル ===== */
:root { --c0: var(--water-deep); --c1: #c2740a; }  /* --c1 はグラフの強調色。--accent(#e2a33b)は白に2.2:1で図形の3:1に届かないため、橙を濃くした（白に3.6:1） */
.sub-btn.done::after { content: " ✓"; }
.cz-claim { margin: 20px 0 14px; background: #fff8e6; border: 2px solid var(--accent); border-left-width: 8px; border-radius: 8px; color: var(--ink); }
.cz-claim summary { display: flex; align-items: center; gap: 10px; padding: 11px 16px; cursor: pointer; list-style: none; font-size: 1.05rem; font-weight: 800; color: #8a5a00; }
.cz-claim summary::-webkit-details-marker { display: none; }
.cz-claim summary::before { content: "▶"; font-size: 0.8em; color: var(--accent); }
.cz-claim[open] summary::before { content: "▼"; }
.cz-claim summary::after { content: "予想したら開きます（タップでも開けます）"; margin-left: auto; font-size: 0.75rem; font-weight: 400; color: #8a7a5a; }
.cz-claim[open] summary::after { content: "閉じる"; }
.cz-claim p { margin: 0; padding: 0 18px 14px 36px; font-size: 1.2rem; font-weight: 800; line-height: 1.6; }
.cz-h { margin: 22px 0 8px; font-size: 0.98rem; color: var(--water-deep); }
.cz-quiz label { display: block; padding: 6px 8px; border-radius: 6px; cursor: pointer; }
.cz-quiz label.right { background: #e3f4ee; }
.cz-quiz label.wrong { background: #fde8e6; }
.legend { display: flex; flex-wrap: wrap; gap: 14px; margin-bottom: 4px; font-size: 0.85rem; }
.legend i { display: inline-block; width: 12px; height: 12px; margin-right: 6px; border-radius: 2px; vertical-align: -1px; }
.chartbox { overflow-x: auto; }
.chartbox svg { display: block; width: 100%; min-width: 420px; height: auto; }
.chartbox svg text { fill: var(--ink); font-size: 12px; }
.chartbox svg .ax { stroke: #c9d3da; }
.cz-pit { margin: 0; padding: 10px 14px; background: #fdf1dc; border-radius: 8px; font-size: 0.92rem; }
.cz-nav { display: flex; flex-wrap: wrap; justify-content: space-between; gap: 8px; margin-top: 20px; }
.cz-nav button { padding: 6px 14px; border: 1px solid var(--water-deep); border-radius: 999px; background: #fff; color: var(--water-deep); font-size: 0.9rem; cursor: pointer; }
.cz-nav button[aria-pressed="true"] { background: var(--water-deep); color: #fff; }
.cz-nav button:disabled { opacity: 0.4; cursor: default; }
.cz-src { margin-top: 18px; font-size: 0.82rem; color: #4a5560; }
.cz-src a { color: var(--water-deep); }
.cz-scope { margin: 12px 0; padding: 12px 14px; background: #e8f3f6; border: 2px solid var(--water-deep); border-radius: 8px; font-size: 0.92rem; }
.cz-scope b { display: block; color: var(--water-deep); font-size: 1rem; }
.cz-scope p { margin: 4px 0 8px; }
.cz-scope.cz-fold { margin: 10px 0; padding: 6px 10px; background: transparent; border: 1px dashed #b8c4c9; border-radius: 6px; font-size: 0.8rem; color: #5f6b73; }
.cz-fold summary { cursor: pointer; color: #5f6b73; font-weight: 400; font-size: 0.8rem; }
.cz-fold[open] summary { margin-bottom: 4px; }
.cz-scope.cz-fold p { margin: 4px 0 6px; }
.cz-scope.cz-fold small { color: #566169; }
.cz-scope.cz-fold .cz-mini { font-size: 0.75rem; color: #4a5560; }
.cz-scope.cz-fold .cz-mini th, .cz-scope.cz-fold .cz-mini td { padding: 2px 6px; border-color: #dfe6e9; }
.cz-scope.cz-fold .cz-mini tr.jp td { background: #f3efe6; }
.cz-scope small { display: block; margin-top: 6px; color: #4a5560; }
.cz-mini { width: 100%; border-collapse: collapse; background: #fff; font-size: 0.85rem; }
.cz-mini th, .cz-mini td { padding: 3px 8px; border: 1px solid var(--water-light); text-align: right; }
.cz-mini th:first-child, .cz-mini td:first-child { text-align: left; }
.cz-mini tr.jp td { font-weight: 700; background: #fdf1dc; }
.cz-banner { margin: 12px 0; padding: 10px 14px; background: #fde8e6; border-left: 6px solid #b5541c; border-radius: 4px; font-weight: 700; font-size: 0.92rem; }
.cz-flag { margin-left: 6px; padding: 0 6px; border-radius: 4px; background: #b5541c; color: #fff; font-size: 0.72rem; }
.sub-btn[aria-pressed="true"] .cz-flag { background: #fff; color: #b5541c; }

/* ===== 項目タブ・グラフ＋出典カード（フェーズ1） ===== */
.cz-itab-bar { display: flex; gap: 2px; margin-bottom: 12px; overflow-x: auto; border-bottom: 2px solid var(--water-light); scrollbar-width: thin; -webkit-overflow-scrolling: touch; }
.cz-itab { flex: 0 0 auto; margin-bottom: -2px; padding: 8px 12px; border: none; border-bottom: 3px solid transparent; background: transparent; color: #4a5560; font-size: 0.88rem; white-space: nowrap; cursor: pointer; }
.cz-itab:hover { color: var(--water-deep); }
.cz-itab[aria-selected="true"] { color: var(--water-deep); font-weight: 700; border-bottom-color: var(--water-deep); }
.cz-itab:focus-visible { outline: 2px solid var(--accent); outline-offset: -2px; }
.cz-fig { margin: 0 0 14px; }
.cz-fig-title { margin: 0 0 4px; font-size: 0.9rem; font-weight: 700; color: var(--ink); }
.cz-fig .view-switch { margin: 4px 0 6px; }
.cz-fig-src { margin: 4px 0 0; font-size: 0.78rem; color: var(--water-deep); }
.cz-card { display: grid; grid-template-columns: minmax(0, 1fr); gap: 8px; margin: 0; padding: 12px 14px; background: #fff; border: 1px solid var(--water-light); border-radius: 8px; font-size: 0.9rem; }
.cz-card > div { display: grid; grid-template-columns: 7em minmax(0, 1fr); gap: 8px; }
.cz-card dt { color: #4a5560; font-size: 0.82rem; }
.cz-card dd { margin: 0; min-width: 0; overflow-wrap: anywhere; }
.cz-card dd.n { font-weight: 700; }
.cz-card dd.pg { font-size: 0.85rem; color: var(--water-deep); }
@media (max-width: 600px) { .cz-card > div { grid-template-columns: minmax(0, 1fr); gap: 0; } }
.chartbox.fit svg { min-width: 0; max-width: 480px; }
.cz-fig-note { margin: 4px 0 0; font-size: 0.78rem; color: #4a5560; }
.cz-tbl { width: 100%; max-width: 480px; border-collapse: collapse; font-size: 0.88rem; }
.cz-tbl th, .cz-tbl td { padding: 4px 8px; border-bottom: 1px solid var(--water-light); text-align: right; }
.cz-tbl th:first-child, .cz-tbl td:first-child { text-align: left; }
.cz-tbl tr:first-child th { color: #4a5560; font-weight: 400; font-size: 0.82rem; }
.cz-table-wrap { overflow-x: auto; }