/* ── Reset & Base ── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --purple:        #7F77DD;
  --purple-dark:   #3C3489;
  --purple-light:  #EEEDFE;
  --purple-mid:    #C5C2F4;
  --pink:          #F472B6;
  --white:         #FFFFFF;
  --text:          #3C3489;
  --correct:       #34D399;
  --correct-bg:    #D1FAE5;
  --wrong:         #F87171;
  --wrong-bg:      #FEE2E2;
  --shadow:        0 4px 0 rgba(0,0,0,.12);
  --radius:        18px;
  --radius-sm:     12px;
}

html, body {
  min-height: 100%;
  font-family: 'Nunito', 'Arial Rounded MT Bold', Arial, sans-serif;
  background: var(--purple-light);
  color: var(--text);
  touch-action: manipulation;
}

/* ── Top Bar ── */
#top-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  background: var(--purple);
  color: var(--white);
  padding: 10px 16px;
  box-shadow: var(--shadow);
  position: sticky;
  top: 0;
  z-index: 50;
  min-height: 52px;
}

#logo {
  font-size: 1.1rem;
  font-weight: 900;
  white-space: nowrap;
}

#header-right {
  display: flex;
  align-items: center;
  gap: 8px;
}

#stars-row {
  display: flex;
  gap: 2px;
  flex-wrap: wrap;
  justify-content: flex-end;
}

.star-pip {
  font-size: 1rem;
  line-height: 1;
  filter: grayscale(1) opacity(.35);
  transition: filter .25s, transform .25s;
}

.star-pip.lit {
  filter: none;
  transform: scale(1.15);
}

/* ── Main ── */
#app {
  padding: 16px 14px 40px;
  display: flex;
  flex-direction: column;
  align-items: center;
}

/* ═══════════════════════════════════════════════════════════════════════════
   Level Select
══════════════════════════════════════════════════════════════════════════ */

#level-select {
  width: 100%;
  max-width: 520px;
  text-align: center;
}

#level-select h1 {
  font-size: 1.7rem;
  color: var(--purple-dark);
  margin-bottom: 6px;
}

#level-select > p {
  color: var(--purple);
  margin-bottom: 24px;
  font-size: 1rem;
}

.level-btn {
  display: flex;
  align-items: center;
  gap: 14px;
  width: 100%;
  background: var(--white);
  border: 3px solid var(--purple-mid);
  border-radius: var(--radius);
  padding: 16px 18px;
  margin-bottom: 14px;
  cursor: pointer;
  text-align: left;
  transition: border-color .15s, transform .1s;
  box-shadow: var(--shadow);
  min-height: 72px;
  font-family: inherit;
}

.level-btn:hover:not(:disabled), .level-btn:focus-visible {
  border-color: var(--purple);
  transform: translateY(-2px);
  outline: none;
}
.level-btn:active:not(:disabled) { transform: translateY(0); }

.level-btn.locked {
  opacity: .55;
  cursor: default;
}

.level-icon { font-size: 2rem; flex-shrink: 0; }

.level-info {
  display: flex;
  flex-direction: column;
  gap: 2px;
  flex: 1 1 0;
  min-width: 0;
}

.level-name {
  font-size: 1.1rem;
  font-weight: 900;
  color: var(--purple-dark);
}

.level-desc {
  font-size: .85rem;
  color: var(--purple);
}

.level-best {
  font-size: .9rem;
  font-weight: 700;
  color: var(--purple);
  white-space: nowrap;
}

/* ═══════════════════════════════════════════════════════════════════════════
   Problem Card
══════════════════════════════════════════════════════════════════════════ */

#problem-card {
  width: 100%;
  max-width: 520px;
  background: var(--white);
  border: 3px solid var(--purple-mid);
  border-radius: var(--radius);
  padding: 16px 0 20px;
  box-shadow: var(--shadow);
  overflow: hidden;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 14px;
}

/* ── Prize popup (correct answer overlay) ── */
#prize-popup {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,.75);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 20px;
  z-index: 300;
  animation: popupIn .2s ease;
  overflow: hidden;
}

@keyframes popupIn {
  from { opacity: 0; transform: scale(.92); }
  to   { opacity: 1; transform: scale(1); }
}

.prize-popup-img {
  max-width: 80vw;
  max-height: 50vh;
  object-fit: contain;
  border-radius: var(--radius);
}

.prize-popup-msg {
  font-size: 1.8rem;
  font-weight: 900;
  color: var(--white);
  text-align: center;
  padding: 0 24px;
  text-shadow: 0 2px 8px rgba(0,0,0,.4);
  animation: bounce .5s ease infinite alternate;
}

.prize-popup-confetti {
  position: absolute;
  inset: 0;
  pointer-events: none;
  overflow: hidden;
}

/* ── Card header (back btn + progress) ── */
.card-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
  padding: 0 16px;
}

.back-btn {
  background: var(--white);
  border: 2px solid var(--purple-mid);
  border-radius: var(--radius-sm);
  padding: 6px 14px;
  font-family: inherit;
  font-size: .9rem;
  font-weight: 700;
  color: var(--purple-dark);
  cursor: pointer;
  min-height: 36px;
  transition: border-color .15s;
}
.back-btn:hover { border-color: var(--purple); }

.progress-label {
  font-size: .9rem;
  font-weight: 700;
  color: var(--purple);
}

/* ── Prompt ── */
.prompt-text {
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--purple-dark);
  text-align: center;
  padding: 0 16px;
  line-height: 1.35;
}

/* ── Objects area ── */
.objects-area {
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 10px;
  padding: 0 12px;
  min-height: 80px;
}

/* Level 1 — listen mode */
.listen-icon {
  font-size: 5rem;
  line-height: 1;
  margin-bottom: 8px;
}

.hear-again-btn {
  background: var(--purple-light);
  border: 3px solid var(--purple-mid);
  border-radius: var(--radius-sm);
  font-family: inherit;
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--purple-dark);
  cursor: pointer;
  padding: 10px 20px;
  min-height: 48px;
  box-shadow: var(--shadow);
  transition: border-color .15s, transform .1s;
}
.hear-again-btn:hover { border-color: var(--purple); transform: translateY(-1px); }
.hear-again-btn:active { transform: translateY(0); }

/* Character image row */
.char-row {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  justify-content: center;
  max-width: 472px; /* 6 × 72px + 5 × 8px gap = 472px */
}

.char-cell {
  position: relative;
  width: 72px;
  height: 72px;
  flex-shrink: 0;
}

.char-cell img {
  width: 72px;
  height: 72px;
  object-fit: contain;
  display: block;
}

.char-placeholder {
  width: 72px;
  height: 72px;
  background: var(--purple);
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 2rem;
  font-weight: 900;
  color: var(--white);
}

/* Red X overlay for subtraction */
.cross-x {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 2rem;
  font-weight: 900;
  color: #DC2626;
  background: rgba(255,255,255,.45);
  border-radius: 6px;
}

/* Addition layout */
.add-row {
  display: flex;
  align-items: center;
  gap: 10px;
  justify-content: center;
  flex-wrap: wrap;
}

.add-group {
  display: flex;
  align-items: center;
  justify-content: center;
}

.big-operator {
  font-size: 72px;
  font-weight: 900;
  color: var(--purple);
  line-height: 1;
  flex-shrink: 0;
}

/* ── Equation ── */
.equation-text {
  font-size: 36px;
  font-weight: 900;
  color: var(--purple-dark);
  text-align: center;
  line-height: 1;
}

/* ── Divider ── */
.divider {
  width: calc(100% - 32px);
  border: none;
  border-top: 2px solid var(--purple-light);
}

/* ── Tap label ── */
.tap-label {
  font-size: .85rem;
  font-weight: 700;
  color: var(--purple);
  text-transform: uppercase;
  letter-spacing: .08em;
}

/* ── Answer buttons ── */
.answers-row {
  display: flex;
  gap: 12px;
  padding: 0 16px;
  width: 100%;
  justify-content: center;
}

.answer-btn {
  flex: 1 1 0;
  min-height: 80px;
  background: var(--purple-light);
  border: 3px solid var(--purple-mid);
  border-radius: var(--radius-sm);
  font-family: inherit;
  font-size: 32px;
  font-weight: 900;
  color: var(--purple-dark);
  cursor: pointer;
  box-shadow: var(--shadow);
  transition: border-color .15s, background .15s, transform .1s;
  touch-action: manipulation;
}

.answer-btn:hover:not(:disabled) {
  border-color: var(--purple);
  transform: translateY(-2px);
}

.answer-btn:active:not(:disabled) { transform: translateY(0); }

.answer-btn:disabled { cursor: default; }

.answer-btn.correct {
  background: var(--correct-bg);
  border-color: var(--correct);
  color: #065F46;
}

.answer-btn.wrong {
  background: var(--wrong-bg);
  border-color: var(--wrong);
  color: #991B1B;
  animation: shake .35s ease;
}

@keyframes shake {
  0%,100% { transform: translateX(0); }
  25%      { transform: translateX(-8px); }
  75%      { transform: translateX(8px); }
}

/* ═══════════════════════════════════════════════════════════════════════════
   Win Screen
══════════════════════════════════════════════════════════════════════════ */

#win-screen {
  position: relative;
  width: 100%;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-height: calc(100vh - 52px);
}

#confetti-container {
  position: fixed;
  inset: 0;
  pointer-events: none;
  overflow: hidden;
  z-index: 10;
}

#win-box {
  position: relative;
  z-index: 20;
  background: var(--white);
  border: 3px solid var(--purple-mid);
  border-radius: var(--radius);
  padding: 28px 24px;
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 14px;
  max-width: 380px;
  width: 92%;
  box-shadow: 0 8px 0 rgba(0,0,0,.13);
}

.win-prize { display: flex; justify-content: center; }

.win-prize-img {
  max-height: 160px;
  max-width: 100%;
  object-fit: contain;
  border-radius: var(--radius-sm);
}

.win-prize-placeholder {
  font-size: 5rem;
  line-height: 1;
}

.win-emoji {
  font-size: 3.5rem;
  animation: bounce .5s ease infinite alternate;
}

@keyframes bounce {
  from { transform: translateY(0); }
  to   { transform: translateY(-12px); }
}

.win-msg {
  font-size: 1.4rem;
  font-weight: 900;
  color: var(--purple-dark);
  line-height: 1.35;
}

.win-stars-line {
  font-size: 1.3rem;
  font-weight: 900;
  color: var(--purple);
}

.win-btns {
  display: flex;
  flex-direction: column;
  gap: 10px;
  width: 100%;
}

.win-btn {
  width: 100%;
  padding: 14px;
  background: var(--purple);
  color: var(--white);
  border: none;
  border-radius: var(--radius-sm);
  font-family: inherit;
  font-size: 1.1rem;
  font-weight: 900;
  cursor: pointer;
  box-shadow: var(--shadow);
  min-height: 52px;
  transition: background .15s, transform .1s;
}

.win-btn:hover { background: var(--purple-dark); transform: translateY(-2px); }
.win-btn:active { transform: translateY(0); }

.win-btn-next {
  background: var(--correct);
  color: #065F46;
}
.win-btn-next:hover { background: #059669; color: var(--white); }

.win-btn-secondary {
  background: var(--white);
  color: var(--purple-dark);
  border: 2px solid var(--purple-mid);
  box-shadow: none;
}
.win-btn-secondary:hover { border-color: var(--purple); background: var(--purple-light); transform: none; }

/* ── Confetti ── */
@keyframes confetti-fall {
  0%   { transform: translateY(-8vh) rotate(0deg);   opacity: 1; }
  100% { transform: translateY(108vh) rotate(720deg); opacity: 0; }
}

.confetti-piece {
  position: absolute;
  top: 0;
  animation: confetti-fall linear forwards;
}

/* ── Responsive ── */
@media (max-width: 400px) {
  .big-operator { font-size: 52px; }
  .equation-text { font-size: 28px; }
  .answer-btn { font-size: 26px; min-height: 68px; }
  .answers-row { gap: 8px; }
  .win-prize-img { max-height: 120px; }
  .char-cell, .char-cell img, .char-placeholder { width: 56px; height: 56px; }
  .char-row { max-width: 368px; gap: 6px; } /* 6 × 56px + 5 × 6px */
  .prize-popup-msg { font-size: 1.4rem; }
}