:root {
  color-scheme: light;
  font-family:
    Inter, ui-rounded, "SF Pro Rounded", "Segoe UI", system-ui, -apple-system,
    sans-serif;
  color: #182338;
  background: #f4f7fb;
  font-synthesis: none;
}

* {
  box-sizing: border-box;
}

html,
body {
  min-width: 0;
  min-height: 100%;
  margin: 0;
  overflow-x: clip;
}

body {
  background:
    radial-gradient(circle at 9% 6%, rgb(88 137 235 / 14%), transparent 29rem),
    radial-gradient(circle at 91% 26%, rgb(63 184 157 / 13%), transparent 27rem),
    #f4f7fb;
}

button,
input {
  font: inherit;
}

[hidden] {
  display: none !important;
}

.term-multiplication-shell {
  width: min(100%, 1500px);
  min-width: 0;
  margin: 0 auto;
  padding:
    max(1rem, env(safe-area-inset-top))
    max(1rem, env(safe-area-inset-right))
    max(1.5rem, env(safe-area-inset-bottom))
    max(1rem, env(safe-area-inset-left));
}

.term-multiplication-header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 1.5rem;
  min-width: 0;
  margin: 0.9rem 0 1.2rem;
}

.term-multiplication-header > div,
.state-panel,
.comparison-card,
.explore-card {
  min-width: 0;
}

.eyebrow,
.subtitle,
.local-note,
.state-question,
.state-formula,
.structure-label,
.measure-caption,
.comparison-kind,
.comparison-formula,
.comparison-summary,
.explore-formula,
.numeric-note,
.insight-text {
  margin: 0;
}

.eyebrow {
  color: #3d5c92;
  font-size: clamp(0.78rem, 1.4vw, 0.98rem);
  font-weight: 800;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

h1 {
  max-width: 25ch;
  margin: 0.35rem 0 0.32rem;
  font-size: clamp(1.75rem, 3.5vw, 3.45rem);
  line-height: 1.04;
  letter-spacing: -0.04em;
  overflow-wrap: anywhere;
}

.subtitle {
  color: #3d5c92;
  font-size: clamp(1rem, 1.8vw, 1.3rem);
  font-weight: 750;
}

.local-note {
  flex: 0 0 auto;
  padding: 0.55rem 0.8rem;
  border: 1px solid #c9d8ed;
  border-radius: 999px;
  color: #47607e;
  background: rgb(255 255 255 / 72%);
  font-size: 0.86rem;
  font-weight: 700;
  white-space: nowrap;
}

.local-note span {
  color: #2c9c79;
}

.term-multiplication-board {
  --fill-scale: 0;
  --fill-opacity: 0.18;
  --segment-size: 5.46rem;
  --square-size: 9.92rem;
  display: grid;
  min-width: 0;
  min-height: clamp(27rem, 56vh, 43rem);
  place-items: center;
  padding: clamp(1rem, 3vw, 2.5rem);
  overflow: hidden;
  border: 1px solid #d8e2f0;
  border-radius: clamp(1.25rem, 3vw, 2.2rem);
  background:
    linear-gradient(rgb(255 255 255 / 89%), rgb(255 255 255 / 89%)),
    linear-gradient(135deg, #eaf1ff, #e8faf4);
  box-shadow: 0 1.2rem 3rem rgb(55 79 116 / 11%);
}

.state-panel {
  width: min(100%, 1220px);
  text-align: center;
}

.irritation-panel,
.addition-panel,
.square-panel,
.comparison-panel,
.explore-panel {
  display: grid;
  place-items: center;
}

.irritation-panel {
  gap: clamp(1.5rem, 4vw, 3rem);
}

.irritation-formulas {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: clamp(0.8rem, 3vw, 2rem);
  min-width: 0;
}

.irritation-formulas p,
.state-formula {
  color: #182338;
  font-size: clamp(2rem, 6vw, 5.2rem);
  font-weight: 830;
  letter-spacing: -0.045em;
  line-height: 1;
}

.irritation-formulas p {
  margin: 0;
  padding: clamp(0.8rem, 2vw, 1.4rem);
  border: 2px solid #c9d8ed;
  border-radius: 1.1rem;
  background: #fff;
}

.irritation-formulas span {
  color: #718097;
  font-weight: 750;
}

.state-question,
.structure-label {
  max-width: 45ch;
  color: #40536f;
  font-size: clamp(1.04rem, 2.1vw, 1.48rem);
  font-weight: 680;
  line-height: 1.35;
}

.state-formula {
  margin-bottom: clamp(0.8rem, 2vw, 1.35rem);
  color: #245b94;
}

.addition-length {
  display: flex;
  justify-content: center;
  min-width: 0;
  max-width: 100%;
  margin-top: clamp(1.5rem, 4vw, 3rem);
}

.addition-segment {
  display: grid;
  inline-size: var(--segment-size);
  max-inline-size: 36vw;
  block-size: clamp(3.2rem, 7vw, 5rem);
  place-items: center;
  border: 3px solid #346db1;
  color: #173f71;
  background: linear-gradient(150deg, #dbeaff, #bcd6fb);
  box-shadow: 0 0.4rem 0.9rem rgb(53 73 104 / 13%);
  font-size: clamp(1.3rem, 3vw, 2rem);
}

.addition-segment:first-child {
  border-radius: 0.9rem 0 0 0.9rem;
}

.addition-segment:last-child {
  margin-left: -3px;
  border-radius: 0 0.9rem 0.9rem 0;
}

.measure-caption {
  margin-top: 1rem;
  color: #3c5575;
  font-size: clamp(1rem, 2vw, 1.3rem);
  font-weight: 780;
}

.square-stage {
  display: grid;
  min-height: clamp(14rem, 30vw, 24rem);
  margin-top: clamp(1.1rem, 3vw, 2rem);
  place-items: center;
}

.square-shape {
  position: relative;
  inline-size: var(--square-size);
  max-inline-size: min(56vw, 22rem);
  aspect-ratio: 1;
  border: 4px solid #2f6fad;
  border-radius: 0.9rem;
  background: #f8fbff;
  box-shadow: 0 0.8rem 1.8rem rgb(47 111 173 / 13%);
}

.square-fill {
  position: absolute;
  inset: 0;
  border-radius: 0.55rem;
  background:
    linear-gradient(rgb(255 255 255 / 24%) 1px, transparent 1px),
    linear-gradient(90deg, rgb(255 255 255 / 24%) 1px, transparent 1px),
    linear-gradient(145deg, #98d9c7, #68bba3);
  background-size: 20% 20%, 20% 20%, auto;
  opacity: var(--fill-opacity);
  transform: scaleY(var(--fill-scale));
  transform-origin: bottom;
}

.square-side {
  position: absolute;
  z-index: 1;
  color: #244665;
  font-size: clamp(0.75rem, 1.5vw, 0.98rem);
  font-weight: 800;
  white-space: nowrap;
}

.square-side-horizontal {
  right: 0;
  bottom: -2rem;
  left: 0;
}

.square-side-vertical {
  top: 50%;
  left: -2.3rem;
  transform: translate(-50%, -50%) rotate(-90deg);
}

.square-area-label {
  position: absolute;
  z-index: 2;
  inset: 50% auto auto 50%;
  color: #174f40;
  font-size: clamp(1rem, 2.5vw, 1.65rem);
  opacity: var(--fill-scale);
  transform: translate(-50%, -50%);
}

.comparison-grid,
.explore-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: clamp(0.9rem, 2.5vw, 1.7rem);
  width: 100%;
  min-width: 0;
}

.comparison-card,
.explore-card {
  display: grid;
  min-height: 20rem;
  align-content: center;
  justify-items: center;
  gap: 1rem;
  padding: clamp(1rem, 2.5vw, 2rem);
  border: 2px solid;
  border-radius: 1.35rem;
}

.length-card {
  border-color: #a9c9ee;
  background: #f4f8ff;
}

.area-card {
  border-color: #a9d9cb;
  background: #f1fbf7;
}

.comparison-kind {
  color: #5c6d84;
  font-size: 0.84rem;
  font-weight: 820;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.comparison-formula,
.explore-formula {
  color: #1f3857;
  font-size: clamp(1.4rem, 3vw, 2.4rem);
  font-weight: 830;
  letter-spacing: -0.035em;
}

.comparison-card > p:last-child {
  max-width: 28ch;
  margin: 0;
  color: #52647d;
  font-weight: 680;
}

.mini-length {
  display: flex;
  width: min(80%, 17rem);
  height: 3.2rem;
}

.mini-length span {
  flex: 1;
  border: 2px solid #346db1;
  background: #c9ddfa;
}

.mini-length span:first-child {
  border-radius: 0.7rem 0 0 0.7rem;
}

.mini-length span:last-child {
  margin-left: -2px;
  border-radius: 0 0.7rem 0.7rem 0;
}

.mini-square,
.explore-square {
  inline-size: clamp(5.5rem, 12vw, 9rem);
  aspect-ratio: 1;
  border: 3px solid #2c896f;
  border-radius: 0.75rem;
  background: linear-gradient(145deg, #c8eee3, #8ed2be);
}

.comparison-summary {
  margin-top: 1rem;
  color: #36506f;
  font-size: clamp(1.05rem, 2.2vw, 1.45rem);
  font-weight: 800;
}

.explore-grid {
  margin-bottom: 1rem;
}

.explore-card {
  min-height: 16rem;
}

.explore-length {
  margin-top: 0.5rem;
}

.explore-square {
  display: grid;
  inline-size: min(var(--square-size), 10rem);
  place-items: center;
  color: #174f40;
  font-size: clamp(1.15rem, 2.7vw, 1.8rem);
}

.range-control {
  display: grid;
  width: min(100%, 42rem);
  min-width: 0;
  gap: 0.45rem;
  margin-top: 0.35rem;
  padding: 0.85rem 1rem;
  border: 1px solid #cad8ea;
  border-radius: 1rem;
  color: #40536f;
  background: rgb(255 255 255 / 88%);
  font-size: 0.92rem;
  font-weight: 720;
  text-align: left;
}

.range-control strong {
  color: #235992;
  font-size: 1.15rem;
}

.range-control input[type="range"] {
  width: 100%;
  min-height: 2.75rem;
  margin: 0;
  accent-color: #2f6fad;
  cursor: pointer;
  touch-action: pan-y;
}

.range-control input[type="range"]:focus-visible,
.primary-button:focus-visible,
.reset-button:focus-visible {
  outline: 4px solid rgb(57 116 181 / 28%);
  outline-offset: 3px;
}

.range-scale {
  display: flex;
  justify-content: space-between;
  color: #738198;
  font-size: 0.78rem;
}

.numeric-note {
  max-width: 48rem;
  margin-top: 0.75rem;
  color: #50647d;
  font-size: clamp(0.92rem, 1.8vw, 1.12rem);
  font-weight: 680;
}

.conclusion-card {
  width: min(100%, 58rem);
  margin-top: 0.85rem;
  padding: clamp(0.9rem, 2.2vw, 1.5rem);
  border: 2px solid #8eb7e5;
  border-radius: 1.25rem;
  background: linear-gradient(135deg, #edf5ff, #effbf7);
}

.conclusion-card h2 {
  margin: 0;
  color: #1e4d80;
  font-size: clamp(1.18rem, 2.8vw, 2rem);
  line-height: 1.15;
}

.conclusion-card p {
  margin: 0.45rem 0 0;
  color: #405a77;
  font-size: clamp(0.92rem, 1.8vw, 1.12rem);
  font-weight: 680;
}

.term-multiplication-insight {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  min-width: 0;
  margin-top: 1rem;
  padding: 1rem clamp(1rem, 2.3vw, 1.5rem);
  border: 1px solid #d8e2ef;
  border-radius: 1.25rem;
  background: rgb(255 255 255 / 88%);
  box-shadow: 0 0.7rem 1.8rem rgb(55 79 116 / 8%);
}

.insight-text {
  min-width: 0;
  color: #2d4565;
  font-size: clamp(1rem, 1.8vw, 1.25rem);
  font-weight: 760;
  line-height: 1.3;
}

.term-multiplication-controls {
  display: flex;
  flex: 0 0 auto;
  gap: 0.65rem;
}

.primary-button,
.reset-button {
  min-height: 3rem;
  padding: 0.72rem 1.15rem;
  border: 2px solid transparent;
  border-radius: 0.9rem;
  font-weight: 800;
  cursor: pointer;
}

.primary-button {
  color: #fff;
  background: #2f6fad;
  box-shadow: 0 0.45rem 1rem rgb(47 111 173 / 24%);
}

.reset-button {
  border-color: #c3d1e3;
  color: #40536f;
  background: #f8fafc;
}

button:disabled,
input:disabled {
  cursor: wait;
  opacity: 0.58;
}

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

@media (max-width: 760px) {
  .term-multiplication-header,
  .term-multiplication-insight {
    align-items: stretch;
    flex-direction: column;
  }

  .local-note {
    align-self: flex-start;
  }

  .term-multiplication-board {
    min-height: 31rem;
  }

  .comparison-grid,
  .explore-grid {
    grid-template-columns: 1fr;
  }

  .comparison-card,
  .explore-card {
    min-height: 12.5rem;
  }

  .term-multiplication-controls {
    width: 100%;
  }

  .primary-button,
  .reset-button {
    flex: 1 1 0;
  }
}

@media (max-width: 420px) {
  .term-multiplication-shell {
    padding-right: max(0.65rem, env(safe-area-inset-right));
    padding-left: max(0.65rem, env(safe-area-inset-left));
  }

  .term-multiplication-board {
    min-height: 28rem;
    padding: 0.75rem;
    border-radius: 1.1rem;
  }

  .irritation-formulas {
    gap: 0.45rem;
  }

  .irritation-formulas p {
    padding: 0.65rem 0.55rem;
  }

  .addition-segment {
    max-inline-size: 39vw;
    block-size: 3rem;
  }

  .square-side-vertical {
    left: -1.75rem;
    font-size: 0.68rem;
  }

  .range-control {
    padding: 0.68rem 0.8rem;
  }
}

@media (max-width: 340px) {
  h1 {
    font-size: 1.43rem;
  }

  .term-multiplication-header {
    gap: 0.7rem;
  }

  .local-note {
    padding: 0.42rem 0.62rem;
    font-size: 0.74rem;
  }

  .irritation-formulas span {
    font-size: 0.75rem;
  }

  .square-shape {
    border-width: 3px;
  }

  .term-multiplication-controls {
    flex-direction: column;
  }
}

@media (orientation: portrait) {
  .term-multiplication-board {
    min-height: min(58rem, 62vh);
  }
}

@media (orientation: landscape) and (max-height: 820px) {
  .term-multiplication-header {
    margin-top: 0.4rem;
    margin-bottom: 0.65rem;
  }

  .term-multiplication-board {
    min-height: 22rem;
    padding-block: 0.85rem;
  }

  .comparison-card,
  .explore-card {
    min-height: 13rem;
  }

  .square-stage {
    min-height: 14rem;
    margin-top: 0.5rem;
  }
}

@media (min-width: 1500px) {
  .term-multiplication-shell {
    width: min(94vw, 1720px);
  }

  .term-multiplication-board {
    min-height: 44rem;
  }

  .state-question,
  .structure-label,
  .insight-text {
    font-size: 1.45rem;
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    scroll-behavior: auto !important;
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
  }
}