:root {
  --ink: #1b2653;
  --navy: #233876;
  --navy-deep: #172653;
  --cream: #f7f4ec;
  --paper: #fffdf8;
  --yellow: #ffcc4d;
  --orange: #ff785a;
  --mint: #62d2b1;
  --sky: #72b8f1;
  --purple: #9b84e8;
  --line: rgba(35, 56, 118, 0.16);
  --shadow: 0 18px 44px rgba(27, 38, 83, 0.13);
  --soft-shadow: 0 8px 22px rgba(27, 38, 83, 0.1);
  --radius: 22px;
  color-scheme: light;
}

* {
  box-sizing: border-box;
}

html {
  min-height: 100%;
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-width: 320px;
  min-height: 100%;
  color: var(--ink);
  background:
    radial-gradient(circle at 8% 6%, rgba(255, 204, 77, 0.22), transparent 23rem),
    radial-gradient(circle at 92% 40%, rgba(98, 210, 177, 0.17), transparent 26rem),
    var(--cream);
  font-family: "Yu Gothic UI", "Hiragino Kaku Gothic ProN", Meiryo, sans-serif;
  font-weight: 600;
  -webkit-font-smoothing: antialiased;
}

button,
input {
  font: inherit;
}

button {
  color: inherit;
}

button:focus-visible,
a:focus-visible {
  outline: 4px solid rgba(255, 120, 90, 0.36);
  outline-offset: 3px;
}

[hidden] {
  display: none !important;
}

.app-shell {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

.site-header {
  width: min(1180px, calc(100% - 40px));
  min-height: 84px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  color: var(--navy);
  text-decoration: none;
  font-size: 1.23rem;
  font-weight: 900;
  letter-spacing: 0.02em;
}

.brand-mark,
.mini-fraction {
  display: inline-grid;
  grid-template-rows: 1fr 3px 1fr;
  place-items: center;
  line-height: 0.9;
  flex: 0 0 auto;
}

.brand-mark {
  width: 42px;
  height: 52px;
  padding: 6px 8px;
  color: white;
  background: var(--navy);
  border-radius: 9px;
  transform: rotate(-4deg);
  box-shadow: 3px 4px 0 var(--yellow);
}

.brand-mark b {
  font-size: 0.9rem;
}

.brand-mark i,
.mini-fraction i {
  width: 100%;
  height: 3px;
  background: currentColor;
  border-radius: 3px;
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 10px;
}

.icon-button,
.small-button,
.back-button,
.modal-close {
  border: 1px solid var(--line);
  background: rgba(255, 253, 248, 0.72);
  cursor: pointer;
  transition: transform 160ms ease, background 160ms ease, box-shadow 160ms ease;
}

.icon-button:hover,
.small-button:hover,
.back-button:hover,
.modal-close:hover {
  transform: translateY(-2px);
  background: white;
  box-shadow: var(--soft-shadow);
}

.icon-button {
  width: 42px;
  height: 42px;
  border-radius: 50%;
  font-size: 1.15rem;
  font-weight: 900;
}

.icon-button.is-muted {
  opacity: 0.52;
  text-decoration: line-through;
}

.small-button {
  min-height: 42px;
  padding: 0 17px;
  border-radius: 999px;
  font-size: 0.87rem;
  font-weight: 800;
}

main {
  width: min(1180px, calc(100% - 40px));
  margin: 0 auto;
  flex: 1;
}

.hero {
  position: relative;
  min-height: 460px;
  overflow: hidden;
  display: grid;
  grid-template-columns: 1.08fr 0.92fr;
  align-items: center;
  padding: clamp(38px, 6vw, 74px);
  color: white;
  background:
    linear-gradient(130deg, rgba(35, 56, 118, 0.96), rgba(23, 38, 83, 0.98)),
    var(--navy);
  border-radius: 32px;
  box-shadow: var(--shadow);
}

.hero::before {
  content: "";
  position: absolute;
  width: 420px;
  height: 420px;
  top: -240px;
  left: -140px;
  border: 1px solid rgba(255, 255, 255, 0.12);
  border-radius: 50%;
  box-shadow: 0 0 0 46px rgba(255, 255, 255, 0.025), 0 0 0 92px rgba(255, 255, 255, 0.018);
}

.hero-copy {
  position: relative;
  z-index: 2;
}

.eyebrow {
  margin: 0 0 12px;
  color: var(--orange);
  font-size: 0.75rem;
  font-weight: 900;
  letter-spacing: 0.2em;
  text-transform: uppercase;
}

.hero .eyebrow {
  color: var(--yellow);
}

.hero h1 {
  max-width: 680px;
  margin: 0;
  font-size: clamp(2.45rem, 5.2vw, 4.65rem);
  line-height: 1.13;
  letter-spacing: -0.055em;
}

.hero h1 span {
  color: var(--yellow);
}

.hero-lead {
  margin: 25px 0 0;
  color: rgba(255, 255, 255, 0.8);
  font-size: clamp(0.95rem, 1.6vw, 1.1rem);
  line-height: 1.9;
}

.hero-tags {
  margin-top: 28px;
  display: flex;
  flex-wrap: wrap;
  gap: 9px;
}

.hero-tags span {
  padding: 7px 12px;
  border: 1px solid rgba(255, 255, 255, 0.18);
  border-radius: 999px;
  color: rgba(255, 255, 255, 0.84);
  font-size: 0.76rem;
}

.hero-art {
  position: relative;
  align-self: stretch;
  min-height: 320px;
}

.orbit {
  position: absolute;
  border: 1px solid rgba(255, 255, 255, 0.15);
  border-radius: 50%;
}

.orbit-one {
  inset: 12% 2% 4% 12%;
}

.orbit-two {
  inset: 24% 17% 16% 0;
}

.floating-card {
  position: absolute;
  width: clamp(125px, 14vw, 168px);
  aspect-ratio: 0.7;
  display: grid;
  grid-template-rows: 1fr 9px 1fr;
  place-items: center;
  padding: 28px;
  color: var(--navy);
  background: white;
  border: 7px solid rgba(255, 255, 255, 0.22);
  border-radius: 18px;
  background-clip: padding-box;
  box-shadow: 0 24px 38px rgba(4, 12, 37, 0.3);
  font-family: Arial, sans-serif;
  font-size: clamp(2.5rem, 5vw, 4.1rem);
  font-weight: 800;
  line-height: 0.9;
}

.floating-card i {
  width: 100%;
  height: 7px;
  background: var(--navy);
  border-radius: 5px;
}

.card-a {
  top: 20%;
  left: 8%;
  transform: rotate(-10deg);
  animation: float-a 4.8s ease-in-out infinite;
}

.card-b {
  right: 3%;
  bottom: 10%;
  transform: rotate(9deg);
  animation: float-b 5.3s ease-in-out infinite;
}

.equal-badge {
  position: absolute;
  z-index: 2;
  top: 46%;
  left: 49%;
  width: 72px;
  height: 72px;
  display: grid;
  place-items: center;
  color: var(--navy);
  background: var(--yellow);
  border-radius: 50%;
  box-shadow: 0 10px 25px rgba(4, 12, 37, 0.25);
  font-size: 2rem;
  font-weight: 900;
  transform: translate(-50%, -50%) rotate(-4deg);
}

@keyframes float-a {
  0%, 100% { transform: rotate(-10deg) translateY(0); }
  50% { transform: rotate(-7deg) translateY(-12px); }
}

@keyframes float-b {
  0%, 100% { transform: rotate(9deg) translateY(0); }
  50% { transform: rotate(6deg) translateY(10px); }
}

.mode-section {
  padding: 80px 0 40px;
}

.section-heading {
  margin-bottom: 28px;
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 24px;
}

.section-heading h2 {
  margin: 0;
  font-size: clamp(1.7rem, 3vw, 2.35rem);
  letter-spacing: -0.04em;
}

.section-heading > p {
  max-width: 390px;
  margin: 0 0 3px;
  color: rgba(27, 38, 83, 0.66);
  font-size: 0.88rem;
  line-height: 1.75;
}

.mode-grid {
  display: grid;
  grid-template-columns: repeat(6, 1fr);
  gap: 15px;
}

.mode-card {
  position: relative;
  min-height: 205px;
  overflow: hidden;
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  padding: 22px;
  border: 0;
  border-radius: var(--radius);
  color: var(--ink);
  text-align: left;
  cursor: pointer;
  box-shadow: var(--soft-shadow);
  transition: transform 200ms ease, box-shadow 200ms ease;
}

.mode-card::after {
  content: "";
  position: absolute;
  right: -38px;
  top: -45px;
  width: 130px;
  height: 130px;
  border: 1px solid rgba(35, 56, 118, 0.12);
  border-radius: 50%;
}

.mode-card:hover {
  transform: translateY(-6px);
  box-shadow: 0 18px 32px rgba(27, 38, 83, 0.16);
}

.mode-card:nth-child(-n+3) {
  grid-column: span 2;
}

.mode-card:nth-child(4) {
  grid-column: 2 / span 2;
}

.mode-card:nth-child(5) {
  grid-column: 4 / span 2;
}

.mode-memory { background: #ffe293; }
.mode-compare { background: #bdebdc; }
.mode-add { background: #cbe7ff; }
.mode-subtract { background: #dbd2fa; }
.mode-one { background: #ffc9bd; }

.mode-number {
  color: rgba(27, 38, 83, 0.52);
  font-size: 0.73rem;
  font-weight: 900;
  letter-spacing: 0.15em;
}

.mode-icon {
  min-height: 70px;
  display: flex;
  align-items: center;
  font-family: Arial, sans-serif;
  font-size: 3.2rem;
  font-weight: 900;
  letter-spacing: -0.08em;
}

.mode-copy {
  display: flex;
  flex-direction: column;
  gap: 3px;
}

.mode-copy strong {
  font-size: 1.1rem;
  font-weight: 900;
}

.mode-copy small {
  color: rgba(27, 38, 83, 0.6);
  font-size: 0.76rem;
}

.mode-arrow {
  position: absolute;
  right: 20px;
  bottom: 21px;
  font-size: 1.25rem;
  transition: transform 180ms ease;
}

.mode-card:hover .mode-arrow {
  transform: translateX(5px);
}

.learning-strip {
  margin: 30px 0 72px;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: clamp(14px, 3vw, 35px);
  padding: 30px 36px;
  color: white;
  background: var(--navy);
  border-radius: var(--radius);
}

.mini-fraction {
  width: 52px;
  height: 72px;
  font-family: Arial, sans-serif;
  font-size: 1.7rem;
}

.strip-symbol {
  color: var(--yellow);
  font-size: 1.8rem;
  font-weight: 900;
}

.learning-strip p {
  margin: 0 0 0 12px;
  color: rgba(255, 255, 255, 0.72);
  font-size: 0.82rem;
  line-height: 1.7;
}

.learning-strip p strong {
  color: white;
  font-size: 1rem;
}

footer {
  width: min(1180px, calc(100% - 40px));
  margin: 0 auto;
  min-height: 88px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  border-top: 1px solid var(--line);
  color: rgba(27, 38, 83, 0.5);
  font-size: 0.72rem;
}

footer p {
  margin: 0;
}

/* Game shell */
.game-screen {
  min-height: calc(100vh - 172px);
  padding-bottom: 70px;
}

.game-toolbar {
  min-height: 94px;
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  gap: 20px;
  border-bottom: 1px solid var(--line);
}

.back-button {
  justify-self: start;
  padding: 10px 15px;
  border-radius: 999px;
  color: rgba(27, 38, 83, 0.73);
  font-size: 0.78rem;
  font-weight: 800;
}

.game-title-wrap {
  text-align: center;
}

.game-title-wrap p {
  margin: 0 0 3px;
  color: var(--orange);
  font-size: 0.63rem;
  font-weight: 900;
  letter-spacing: 0.15em;
}

.game-title-wrap h1 {
  margin: 0;
  font-size: 1.45rem;
  letter-spacing: -0.04em;
}

.opponent-badge {
  display: inline-block;
  margin-top: 5px;
  padding: 3px 8px;
  color: var(--navy);
  background: rgba(35, 56, 118, 0.08);
  border-radius: 999px;
  font-size: 0.58rem;
  font-weight: 900;
  letter-spacing: 0.06em;
}

.game-toolbar .small-button {
  justify-self: end;
}

.score-area {
  display: flex;
  justify-content: center;
  padding: 26px 0 0;
}

.scoreboard {
  min-width: min(560px, 100%);
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  gap: 20px;
  padding: 13px 18px;
  background: rgba(255, 253, 248, 0.76);
  border: 1px solid var(--line);
  border-radius: 17px;
}

.score-player {
  display: flex;
  align-items: center;
  gap: 10px;
}

.score-player.is-cpu {
  flex-direction: row-reverse;
  text-align: right;
}

.avatar {
  width: 36px;
  height: 36px;
  display: grid;
  place-items: center;
  flex: 0 0 auto;
  border-radius: 50%;
  background: #cbe7ff;
  font-size: 0.98rem;
}

.is-cpu .avatar {
  background: #ffc9bd;
}

.score-label {
  display: flex;
  flex-direction: column;
  gap: 1px;
}

.score-label small {
  color: rgba(27, 38, 83, 0.5);
  font-size: 0.62rem;
  letter-spacing: 0.08em;
}

.score-label strong {
  font-size: 0.92rem;
}

.score-value {
  margin-left: auto;
  font-family: Arial, sans-serif;
  font-size: 1.35rem;
  font-weight: 900;
}

.is-cpu .score-value {
  margin: 0 auto 0 0;
}

.score-divider {
  color: rgba(27, 38, 83, 0.26);
  font-size: 0.7rem;
  font-weight: 900;
  letter-spacing: 0.1em;
}

.message-area {
  min-height: 70px;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 17px 12px 12px;
  text-align: center;
}

.turn-message {
  margin: 0;
  font-size: clamp(0.95rem, 2vw, 1.08rem);
  font-weight: 900;
}

.turn-message span {
  display: block;
  margin-top: 5px;
  color: rgba(27, 38, 83, 0.55);
  font-size: 0.7rem;
  font-weight: 700;
}

.game-area {
  min-height: 300px;
}

.action-area {
  min-height: 74px;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-wrap: wrap;
  gap: 10px;
  padding-top: 18px;
}

.primary-button,
.secondary-button,
.danger-button {
  min-height: 48px;
  padding: 0 25px;
  border-radius: 999px;
  font-size: 0.88rem;
  font-weight: 900;
  cursor: pointer;
  transition: transform 160ms ease, box-shadow 160ms ease, opacity 160ms ease;
}

.primary-button {
  border: 1px solid var(--navy);
  color: white;
  background: var(--navy);
  box-shadow: 0 8px 18px rgba(35, 56, 118, 0.22);
}

.secondary-button {
  border: 1px solid var(--line);
  color: var(--navy);
  background: white;
}

.danger-button {
  border: 1px solid rgba(255, 120, 90, 0.3);
  color: #a63a27;
  background: #fff0ec;
}

.primary-button:hover,
.secondary-button:hover,
.danger-button:hover {
  transform: translateY(-2px);
  box-shadow: var(--soft-shadow);
}

.primary-button:disabled,
.secondary-button:disabled,
.danger-button:disabled {
  opacity: 0.4;
  pointer-events: none;
}

/* Fraction cards */
.card-grid {
  display: grid;
  grid-template-columns: repeat(10, minmax(54px, 1fr));
  gap: clamp(6px, 0.9vw, 10px);
}

.fraction-card {
  --card-color: var(--yellow);
  position: relative;
  aspect-ratio: 0.72;
  min-width: 0;
  overflow: hidden;
  display: flex;
  flex-direction: column;
  align-items: stretch;
  justify-content: space-between;
  padding: clamp(7px, 1.2vw, 13px);
  border: 2px solid var(--navy);
  border-radius: clamp(9px, 1.2vw, 14px);
  color: var(--navy);
  background: var(--paper);
  box-shadow: 0 5px 0 rgba(35, 56, 118, 0.13);
  cursor: pointer;
  transform-style: preserve-3d;
  transition: transform 170ms ease, box-shadow 170ms ease, opacity 250ms ease;
  -webkit-tap-highlight-color: transparent;
}

.fraction-card:not(:disabled):hover {
  transform: translateY(-4px) rotate(-1deg);
  box-shadow: 0 9px 0 rgba(35, 56, 118, 0.1);
}

.fraction-card:disabled {
  cursor: default;
}

.fraction-card.is-back {
  justify-content: center;
  border-color: #365097;
  color: white;
  background:
    linear-gradient(135deg, rgba(255,255,255,0.08) 25%, transparent 25%) 0 0 / 16px 16px,
    linear-gradient(315deg, rgba(255,255,255,0.08) 25%, transparent 25%) 0 0 / 16px 16px,
    var(--navy);
}

.card-back-mark {
  width: 52%;
  aspect-ratio: 1;
  display: grid;
  place-items: center;
  margin: auto;
  border: 1px solid rgba(255, 255, 255, 0.45);
  border-radius: 50%;
  color: var(--yellow);
  font-family: Arial, sans-serif;
  font-size: clamp(1rem, 2vw, 1.7rem);
  font-weight: 900;
}

.fraction-number {
  min-height: 58%;
  display: grid;
  grid-template-rows: 1fr 4px 1fr;
  place-items: center;
  padding: 0 15%;
  font-family: Arial, sans-serif;
  font-size: clamp(1.15rem, 2.3vw, 1.9rem);
  font-weight: 800;
  line-height: 0.9;
}

.fraction-number i {
  width: 100%;
  height: 3px;
  background: currentColor;
  border-radius: 3px;
}

.fraction-visual {
  width: 100%;
  max-height: 42%;
  overflow: visible;
}

.fraction-visual .segment-filled {
  fill: var(--card-color);
}

.fraction-visual .segment-empty {
  fill: #f2efe6;
}

.fraction-visual line,
.fraction-visual rect.outline {
  stroke: var(--navy);
  stroke-width: 1.8;
}

.fraction-card.is-selected {
  transform: translateY(-9px);
  border-color: var(--orange);
  box-shadow: 0 0 0 4px rgba(255, 120, 90, 0.22), 0 10px 0 rgba(255, 120, 90, 0.16);
}

.fraction-card.is-hint {
  animation: card-hint 760ms ease 2;
}

.fraction-card.is-matched {
  opacity: 0;
  transform: scale(0.72) rotate(6deg);
  pointer-events: none;
}

@keyframes card-hint {
  0%, 100% { box-shadow: 0 5px 0 rgba(35, 56, 118, 0.13); }
  50% { box-shadow: 0 0 0 6px rgba(98, 210, 177, 0.42), 0 9px 0 rgba(35, 56, 118, 0.1); }
}

/* Battle layouts */
.battle-board {
  display: grid;
  grid-template-columns: 1fr minmax(74px, 110px) 1fr;
  align-items: center;
  gap: clamp(16px, 4vw, 52px);
  max-width: 830px;
  margin: 0 auto;
  padding: 18px clamp(12px, 3vw, 30px) 30px;
}

.battle-side {
  min-height: 235px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 12px;
  padding: 20px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: rgba(255, 253, 248, 0.72);
}

.battle-side h3,
.hand-zone h3,
.field-heading h3 {
  margin: 0;
  color: rgba(27, 38, 83, 0.58);
  font-size: 0.72rem;
  letter-spacing: 0.09em;
}

.battle-side .fraction-card {
  width: 124px;
}

.battle-center {
  text-align: center;
}

.battle-symbol {
  width: 70px;
  height: 70px;
  display: grid;
  place-items: center;
  margin: 0 auto;
  color: white;
  background: var(--orange);
  border-radius: 50%;
  box-shadow: var(--soft-shadow);
  font-family: Arial, sans-serif;
  font-size: 1.9rem;
  font-weight: 900;
}

.battle-result {
  margin-top: 10px;
  font-size: 0.78rem;
  font-weight: 900;
}

.hand-zone {
  max-width: 920px;
  margin: 10px auto 0;
  padding: 20px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: rgba(255, 253, 248, 0.64);
}

.hand-zone h3 {
  margin-bottom: 14px;
  text-align: center;
}

.card-hand {
  display: flex;
  align-items: flex-end;
  justify-content: center;
  gap: clamp(7px, 1.4vw, 13px);
}

.card-hand .fraction-card {
  width: min(104px, 13vw);
}

.round-dots {
  display: flex;
  justify-content: center;
  gap: 7px;
  margin-top: 18px;
}

.battle-board > .round-dots {
  grid-column: 1 / -1;
  width: 100%;
}

.round-dot {
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: rgba(35, 56, 118, 0.15);
}

.round-dot.is-done { background: var(--navy); }
.round-dot.is-current { background: var(--orange); transform: scale(1.3); }

.math-expression {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
}

.math-expression .fraction-card {
  width: 104px;
}

.math-operator {
  font-family: Arial, sans-serif;
  font-size: 1.7rem;
  font-weight: 900;
}

.answer-pill {
  min-width: 74px;
  padding: 10px 13px;
  color: white;
  background: var(--navy);
  border-radius: 12px;
  text-align: center;
  font-family: Arial, sans-serif;
  font-size: 1rem;
  font-weight: 900;
}

.countdown-badge {
  width: 72px;
  height: 72px;
  display: grid;
  place-items: center;
  margin: 0 auto;
  color: var(--navy);
  background: var(--yellow);
  border-radius: 50%;
  box-shadow: 0 0 0 10px rgba(255, 204, 77, 0.18);
  font-family: Arial, sans-serif;
  font-size: 2rem;
  font-weight: 900;
}

.answer-panel {
  width: min(330px, 100%);
  display: grid;
  gap: 10px;
  padding: 16px;
  background: rgba(255, 253, 248, 0.92);
  border: 1px solid var(--line);
  border-radius: 20px;
  box-shadow: var(--soft-shadow);
}

.answer-panel h3 {
  margin: 0;
  text-align: center;
  font-size: 0.83rem;
}

.answer-display {
  min-height: 52px;
  display: flex;
  align-items: center;
  justify-content: flex-end;
  padding: 8px 16px;
  color: var(--navy);
  background: #f2efe6;
  border: 2px solid rgba(35, 56, 118, 0.18);
  border-radius: 12px;
  font-family: Arial, sans-serif;
  font-size: 1.7rem;
  font-weight: 900;
  letter-spacing: 0.04em;
}

.answer-display.is-empty {
  color: rgba(35, 56, 118, 0.35);
}

.keypad {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 7px;
}

.key-button {
  min-height: 46px;
  border: 1px solid var(--line);
  border-radius: 11px;
  color: var(--navy);
  background: white;
  font-family: Arial, sans-serif;
  font-size: 1.05rem;
  font-weight: 900;
  cursor: pointer;
}

.key-button:hover {
  border-color: var(--navy);
  background: #f7f4ec;
}

.key-button.is-function {
  color: #a63a27;
  background: #fff0ec;
}

.answer-submit {
  width: 100%;
}

/* Make one */
.one-board {
  max-width: 970px;
  margin: 0 auto;
  padding: 8px 0 20px;
}

.field-heading {
  margin-bottom: 15px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 14px;
}

.deck-counter {
  padding: 7px 12px;
  color: var(--navy);
  background: white;
  border: 1px solid var(--line);
  border-radius: 999px;
  font-size: 0.72rem;
}

.field-cards {
  min-height: 180px;
  display: grid;
  grid-template-columns: repeat(8, minmax(70px, 1fr));
  gap: 10px;
  align-items: start;
  padding: clamp(16px, 3vw, 26px);
  background: rgba(98, 210, 177, 0.13);
  border: 1px dashed rgba(35, 56, 118, 0.28);
  border-radius: var(--radius);
}

.field-cards .fraction-card {
  width: 100%;
}

.selection-total {
  min-width: 130px;
  padding: 10px 18px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: white;
  text-align: center;
  font-size: 0.78rem;
}

.selection-total strong {
  margin-left: 6px;
  color: var(--orange);
  font-family: Arial, sans-serif;
  font-size: 1.08rem;
}

/* Dialogs */
.modal {
  width: min(620px, calc(100% - 30px));
  max-height: min(82vh, 740px);
  overflow: auto;
  padding: clamp(24px, 4vw, 38px);
  border: 0;
  border-radius: 25px;
  color: var(--ink);
  background: var(--paper);
  box-shadow: 0 34px 90px rgba(12, 23, 58, 0.33);
}

.modal::backdrop {
  background: rgba(16, 26, 60, 0.62);
  backdrop-filter: blur(5px);
}

.modal-head {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 20px;
  padding-bottom: 20px;
  border-bottom: 1px solid var(--line);
}

.modal h2 {
  margin: 0;
  font-size: 1.7rem;
  letter-spacing: -0.04em;
}

.modal-close {
  width: 40px;
  height: 40px;
  flex: 0 0 auto;
  border-radius: 50%;
  font-size: 1.35rem;
  line-height: 1;
}

.rules-content {
  padding-top: 22px;
}

.rules-content h3 {
  margin: 25px 0 8px;
  color: var(--navy);
  font-size: 1rem;
}

.rules-content h3:first-child {
  margin-top: 0;
}

.rules-content p,
.rules-content li {
  color: rgba(27, 38, 83, 0.74);
  font-size: 0.86rem;
  line-height: 1.85;
}

.rules-content ol,
.rules-content ul {
  margin: 10px 0 0;
  padding-left: 1.35rem;
}

.rules-list {
  display: grid;
  gap: 10px;
}

.rule-choice {
  width: 100%;
  display: flex;
  align-items: center;
  gap: 15px;
  padding: 14px 16px;
  border: 1px solid var(--line);
  border-radius: 15px;
  background: white;
  text-align: left;
  cursor: pointer;
}

.rule-choice:hover {
  border-color: var(--navy);
}

.rule-choice b {
  min-width: 29px;
  color: var(--orange);
  font-family: Arial, sans-serif;
}

.rule-choice span {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.rule-choice strong { font-size: 0.9rem; }
.rule-choice small { color: rgba(27, 38, 83, 0.55); font-size: 0.72rem; }

.result-modal {
  overflow: hidden;
  text-align: center;
}

.result-burst {
  width: 82px;
  height: 82px;
  display: grid;
  place-items: center;
  margin: 0 auto 20px;
  color: var(--navy);
  background: var(--yellow);
  border-radius: 50%;
  box-shadow: 0 0 0 13px rgba(255, 204, 77, 0.18);
  font-size: 2.1rem;
}

.result-modal h2 {
  font-size: clamp(2rem, 6vw, 3rem);
}

.result-score {
  margin: 18px 0 0;
  font-size: 1.05rem;
  font-weight: 900;
}

.result-record {
  margin: 7px 0 0;
  color: rgba(27, 38, 83, 0.57);
  font-size: 0.76rem;
}

.modal-actions {
  margin-top: 28px;
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: 10px;
}

.opponent-lead {
  margin: 22px 0 16px;
  color: rgba(27, 38, 83, 0.68);
  font-size: 0.86rem;
}

.opponent-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
}

.opponent-choice {
  min-height: 170px;
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  justify-content: space-between;
  gap: 18px;
  padding: 20px;
  border: 1px solid rgba(35, 56, 118, 0.18);
  border-radius: 18px;
  color: var(--navy);
  background: #cbe7ff;
  text-align: left;
  cursor: pointer;
  transition: transform 170ms ease, box-shadow 170ms ease;
}

.opponent-choice.is-pvp {
  background: #ffe293;
}

.opponent-choice:hover {
  transform: translateY(-4px);
  box-shadow: var(--soft-shadow);
}

.opponent-choice > span:last-child {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.opponent-choice strong {
  font-size: 1rem;
}

.opponent-choice small {
  color: rgba(27, 38, 83, 0.58);
  font-size: 0.7rem;
  line-height: 1.5;
}

.opponent-icon {
  min-height: 48px;
  display: flex;
  align-items: center;
  font-size: 1.7rem;
  font-weight: 900;
  letter-spacing: 0.08em;
}

.handoff-modal {
  max-width: 460px;
  text-align: center;
}

.handoff-mark {
  width: 76px;
  height: 76px;
  display: grid;
  place-items: center;
  margin: 0 auto 20px;
  color: var(--navy);
  background: var(--yellow);
  border-radius: 50%;
  font-size: 2.2rem;
  font-weight: 900;
}

.handoff-modal p:not(.eyebrow) {
  margin: 14px auto 24px;
  color: rgba(27, 38, 83, 0.64);
  font-size: 0.84rem;
  line-height: 1.8;
}

.toast {
  position: fixed;
  z-index: 20;
  left: 50%;
  bottom: max(24px, env(safe-area-inset-bottom));
  max-width: calc(100% - 30px);
  padding: 12px 18px;
  color: white;
  background: var(--navy-deep);
  border-radius: 999px;
  box-shadow: var(--shadow);
  font-size: 0.78rem;
  opacity: 0;
  pointer-events: none;
  transform: translate(-50%, 16px);
  transition: opacity 180ms ease, transform 180ms ease;
}

.toast.is-visible {
  opacity: 1;
  transform: translate(-50%, 0);
}

@media (max-width: 900px) {
  .hero {
    min-height: 420px;
    grid-template-columns: 1fr 0.7fr;
  }

  .hero-art {
    margin-right: -35px;
  }

  .equal-badge {
    width: 58px;
    height: 58px;
  }

  .card-grid {
    grid-template-columns: repeat(6, minmax(55px, 1fr));
  }

  .field-cards {
    grid-template-columns: repeat(6, minmax(68px, 1fr));
  }

  .battle-side {
    padding: 14px;
  }

  .math-expression .fraction-card {
    width: 88px;
  }
}

@media (max-width: 680px) {
  .site-header,
  main,
  footer {
    width: min(100% - 24px, 1180px);
  }

  .site-header {
    min-height: 70px;
  }

  .brand {
    font-size: 1rem;
  }

  .brand-mark {
    width: 34px;
    height: 43px;
  }

  .header-actions .small-button {
    display: none;
  }

  .hero {
    min-height: 570px;
    grid-template-columns: 1fr;
    align-content: start;
    padding: 38px 27px;
    border-radius: 24px;
  }

  .hero h1 {
    font-size: clamp(2.3rem, 11vw, 3.55rem);
  }

  .hero-lead br {
    display: none;
  }

  .hero-art {
    min-height: 230px;
    margin: 15px -25px -25px 0;
  }

  .floating-card {
    width: 108px;
    padding: 20px;
    border-width: 5px;
    font-size: 2.4rem;
  }

  .card-a { top: 9%; left: 11%; }
  .card-b { right: 10%; bottom: 3%; }
  .equal-badge { top: 47%; left: 52%; }

  .mode-section {
    padding-top: 58px;
  }

  .section-heading {
    align-items: flex-start;
    flex-direction: column;
    gap: 10px;
  }

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

  .mode-card,
  .mode-card:nth-child(-n+3),
  .mode-card:nth-child(4),
  .mode-card:nth-child(5) {
    grid-column: auto;
  }

  .mode-card {
    min-height: 125px;
    display: grid;
    grid-template-columns: 46px 70px 1fr 24px;
    align-items: center;
    gap: 6px;
    padding: 18px;
  }

  .mode-number { align-self: start; }
  .mode-icon { min-height: auto; font-size: 2.65rem; }
  .mode-arrow { position: static; }

  .learning-strip {
    flex-wrap: wrap;
    padding: 25px 22px;
  }

  .learning-strip p {
    width: 100%;
    margin: 8px 0 0;
    text-align: center;
  }

  footer {
    min-height: 74px;
  }

  footer p:last-child {
    display: none;
  }

  .game-toolbar {
    min-height: 78px;
    grid-template-columns: 48px 1fr 48px;
    gap: 6px;
  }

  .back-button,
  .game-toolbar .small-button {
    width: 44px;
    height: 44px;
    overflow: hidden;
    padding: 0;
    display: grid;
    place-items: center;
    border-radius: 50%;
    font-size: 0;
  }

  .back-button span {
    font-size: 1.2rem;
  }

  .game-toolbar .small-button::after {
    content: "?";
    font-size: 1rem;
  }

  .game-title-wrap h1 {
    font-size: 1.18rem;
  }

  .opponent-badge {
    margin-top: 3px;
  }

  .score-area {
    padding-top: 17px;
  }

  .scoreboard {
    gap: 8px;
    padding: 10px 12px;
  }

  .score-player {
    gap: 6px;
  }

  .avatar {
    width: 30px;
    height: 30px;
    font-size: 0.8rem;
  }

  .score-label small {
    display: none;
  }

  .score-label strong {
    font-size: 0.72rem;
  }

  .score-value {
    font-size: 1.05rem;
  }

  .message-area {
    min-height: 64px;
  }

  .card-grid {
    grid-template-columns: repeat(5, minmax(44px, 1fr));
    gap: 6px;
  }

  .fraction-card {
    padding: 6px;
    border-width: 1.5px;
    border-radius: 8px;
  }

  .fraction-number {
    font-size: clamp(0.92rem, 5vw, 1.25rem);
  }

  .battle-board {
    grid-template-columns: minmax(0, 1fr) 44px minmax(0, 1fr);
    gap: 8px;
    padding: 7px 0 20px;
  }

  .battle-side {
    min-height: 180px;
    min-width: 0;
    overflow: hidden;
    padding: 10px 6px;
    border-radius: 15px;
  }

  .battle-side .fraction-card {
    width: min(95px, 26vw);
  }

  .battle-symbol {
    width: 46px;
    height: 46px;
    font-size: 1.2rem;
  }

  .battle-result {
    font-size: 0.65rem;
  }

  .hand-zone {
    padding: 14px 7px;
  }

  .card-hand {
    gap: 4px;
    flex-wrap: wrap;
  }

  .card-hand .fraction-card {
    width: calc((100% - 12px) / 4);
  }

  .math-expression {
    gap: 4px;
  }

  .math-expression .fraction-card {
    width: min(78px, 20vw);
  }

  .battle-side .math-expression {
    width: 100%;
    flex-wrap: wrap;
    gap: 3px;
  }

  .battle-side .math-expression .fraction-card {
    width: 47px;
    flex: 0 0 47px;
  }

  .battle-side .math-expression .answer-pill {
    flex: 1 0 100%;
    margin-top: 4px;
  }

  .battle-side .math-operator {
    font-size: 0.9rem;
  }

  .math-operator {
    font-size: 1.15rem;
  }

  .answer-pill {
    min-width: 52px;
    padding: 8px 6px;
    font-size: 0.8rem;
  }

  .answer-panel {
    padding: 12px;
  }

  .key-button {
    min-height: 44px;
  }

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

  .opponent-choice {
    min-height: 120px;
    flex-direction: row;
    align-items: center;
  }

  .field-cards {
    min-height: 150px;
    grid-template-columns: repeat(5, minmax(50px, 1fr));
    gap: 6px;
    padding: 12px;
  }

  .action-area {
    padding-top: 14px;
  }

  .primary-button,
  .secondary-button,
  .danger-button {
    min-height: 45px;
    padding: 0 18px;
    font-size: 0.78rem;
  }
}

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