:root {
  --bg: #f0f9ff;
  --card: #ffffff;
  --border: #bae6fd;
  --text: #0f172a;
  --muted: #64748b;

  --primary: #0ea5e9;
  --primary-dark: #0284c7;
  
  --green: #10b981;
  --green-dark: #059669;

  --yellow: #f59e0b;
  --yellow-dark: #d97706;

  --soft: #e0f2fe;
  --soft-dark: #bae6fd;

  --answer: #f8fafc;
  --answer-border: #e2e8f0;
  
  --correct: #d1fae5;
  --correct-border: #10b981;
  
  --wrong: #fee2e2;
  --wrong-border: #ef4444;

  --shadow: 0 10px 30px -10px rgba(2, 132, 199, 0.15);
  --shadow-hover: 0 15px 35px -5px rgba(2, 132, 199, 0.2);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
}

.hidden {
  display: none !important;
}

/* Animations */
@keyframes slideUp {
  from { opacity: 0; transform: translateY(20px); }
  to { opacity: 1; transform: translateY(0); }
}
@keyframes bounce {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-8px); }
}
@keyframes shake {
  0%, 100% { transform: translateX(0); }
  25% { transform: translateX(-6px); }
  75% { transform: translateX(6px); }
}
@keyframes pulse {
  0% { transform: scale(1); }
  50% { transform: scale(1.03); }
  100% { transform: scale(1); }
}

.screen:not(.hidden) {
  animation: slideUp 0.4s cubic-bezier(0.16, 1, 0.3, 1) forwards;
}

#confetti-canvas {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  pointer-events: none;
  z-index: 9999;
}

#app {
  max-width: 760px;
  margin: 0 auto;
  padding: 30px 16px 60px;
}

h1, h2, h3, p {
  margin-top: 0;
}

h1 {
  font-size: 2.8rem;
  font-weight: 800;
  color: var(--primary-dark);
  margin-bottom: 10px;
  letter-spacing: -1px;
}

#startScreen {
  text-align: center;
}

.introText {
  font-size: 1.15rem;
  color: var(--text);
  max-width: 600px;
  margin: 0 auto 24px;
}

/* Filters */
.filterBar {
  display: flex;
  flex-direction: column;
  gap: 16px;
  margin: 20px auto 30px;
  max-width: 650px;
  background: var(--card);
  padding: 16px;
  border-radius: 24px;
  box-shadow: var(--shadow);
  border: 2px solid var(--border);
}

.filterGroup {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
}

.filterTitle {
  margin: 0;
  font-weight: 700;
  color: var(--muted);
  font-size: 0.95rem;
  text-transform: uppercase;
  letter-spacing: 1px;
}

.filterTabs {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 8px;
}

.tabBtn {
  background: var(--answer);
  border: 1px solid var(--answer-border);
  color: var(--muted);
  padding: 8px 16px;
  border-radius: 30px;
  font-size: 0.95rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s;
  font-family: inherit;
}

.tabBtn:hover {
  background: var(--soft);
  color: var(--primary-dark);
}

.tabBtn.active {
  background: var(--primary);
  color: #fff;
  border-color: var(--primary-dark);
  box-shadow: 0 4px 10px rgba(14, 165, 233, 0.3);
}

.tabBtn.active.easy { background: var(--green); border-color: var(--green-dark); box-shadow: 0 4px 10px rgba(16, 185, 129, 0.3); }
.tabBtn.active.medium { background: var(--yellow); border-color: var(--yellow-dark); box-shadow: 0 4px 10px rgba(245, 158, 11, 0.3); }
.tabBtn.active.hard { background: #ef4444; border-color: #b91c1c; box-shadow: 0 4px 10px rgba(239, 68, 68, 0.3); }

/* Level Mini Info */
.levelOverviewCompact {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  justify-content: center;
  margin: 0 auto 24px;
}

.levelMini {
  display: inline-flex;
  align-items: center;
  padding: 8px 14px;
  border-radius: 30px;
  font-size: 0.9rem;
  font-weight: 700;
}
.levelMini.easy { background: var(--correct); color: var(--green-dark); }
.levelMini.medium { background: #fef3c7; color: var(--yellow-dark); }
.levelMini.hard { background: var(--wrong); color: #b91c1c; }

.chooseText {
  margin-top: 10px;
  font-weight: 800;
  font-size: 1.2rem;
  color: var(--primary-dark);
}

/* Story List */
#storyList {
  display: grid;
  gap: 16px;
}

.storySelectCard {
  width: 100%;
  padding: 20px 24px;
  border: 2px solid var(--border);
  border-radius: 24px;
  background: var(--card);
  color: var(--text);
  text-align: left;
  cursor: pointer;
  transition: transform 0.2s, box-shadow 0.2s, border-color 0.2s;
  box-shadow: var(--shadow);
  display: flex;
  align-items: center;
  gap: 20px;
  font-family: inherit;
}

.storySelectCard:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-hover);
  border-color: var(--primary);
}

.storySelectCard:active {
  transform: scale(0.98);
}

.storySelectEmoji {
  font-size: 3rem;
  flex-shrink: 0;
  filter: drop-shadow(0 4px 6px rgba(0,0,0,0.1));
}

.storyTitleSmall {
  font-size: 1.3rem;
  font-weight: 800;
  margin-bottom: 6px;
  color: var(--text);
}

.storyMeta {
  font-size: 0.95rem;
  color: var(--muted);
  font-weight: 600;
}

/* Screens */
.storyCardLarge,
.quizBox,
.resultBox {
  background: var(--card);
  border: 2px solid var(--border);
  border-radius: 32px;
  padding: 40px 30px;
  text-align: center;
  box-shadow: var(--shadow);
}

.storyEmoji {
  font-size: 5rem;
  margin-bottom: 16px;
  filter: drop-shadow(0 8px 12px rgba(0,0,0,0.1));
}

.storyHint {
  color: var(--muted);
  font-size: 1.1rem;
  margin-bottom: 30px;
}

/* Audio Progress */
.audioProgressContainer {
  width: 100%;
  height: 16px;
  background: var(--soft);
  border-radius: 10px;
  margin-bottom: 30px;
  overflow: hidden;
  position: relative;
  border: 1px solid var(--border);
}

.audioProgressBar {
  height: 100%;
  width: 0%;
  background: var(--primary-gradient, linear-gradient(90deg, #0ea5e9, #0284c7));
  border-radius: 10px;
  transition: width 0.1s linear;
}

/* Buttons */
.storyButtons {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.btnIcon {
  font-size: 1.2rem;
}

.bigBtn {
  width: 100%;
  min-height: 68px;
  padding: 16px 24px;
  border: none;
  border-radius: 20px;
  font-size: 1.25rem;
  font-weight: 800;
  cursor: pointer;
  color: #fff;
  transition: all 0.2s;
  font-family: inherit;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  box-shadow: 0 4px 12px rgba(0,0,0,0.1);
}

.playTheme {
  background: var(--primary);
  border-bottom: 4px solid var(--primary-dark);
}
.playTheme:hover { background: var(--primary-dark); transform: translateY(-2px); }
.playTheme:active { transform: translateY(2px); border-bottom-width: 0; margin-top: 4px; }

.accentBtn {
  background: var(--yellow);
  color: #fff;
  border-bottom: 4px solid var(--yellow-dark);
}
.accentBtn:hover { background: var(--yellow-dark); transform: translateY(-2px); }
.accentBtn:active { transform: translateY(2px); border-bottom-width: 0; margin-top: 4px; }

.nextTheme {
  background: var(--green);
  border-bottom: 4px solid var(--green-dark);
}
.nextTheme:hover { background: var(--green-dark); transform: translateY(-2px); }
.nextTheme:active { transform: translateY(2px); border-bottom-width: 0; margin-top: 4px; }

.backBtn {
  width: 100%;
  min-height: 54px;
  margin-bottom: 24px;
  padding: 14px 20px;
  border: 2px solid var(--border);
  border-radius: 16px;
  font-size: 1.05rem;
  font-weight: 700;
  cursor: pointer;
  background: var(--soft);
  color: var(--primary-dark);
  transition: all 0.2s;
  font-family: inherit;
}
.backBtn:hover {
  background: var(--soft-dark);
  color: #fff;
}
.backBtn:active {
  transform: scale(0.98);
}

/* Quiz UI */
.quizHeader {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 20px;
}

#questionCounter {
  font-weight: 800;
  color: var(--primary);
  font-size: 1.1rem;
  background: var(--soft);
  padding: 6px 14px;
  border-radius: 20px;
}

.ttsBtn {
  background: var(--soft);
  border: 1px solid var(--border);
  border-radius: 50%;
  width: 44px;
  height: 44px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
  cursor: pointer;
  transition: all 0.2s;
  color: var(--primary-dark);
  flex-shrink: 0;
}
.ttsBtn:hover {
  background: var(--primary);
  color: #fff;
  transform: scale(1.1);
}
.ttsBtn:active { transform: scale(0.95); }

#questionText {
  font-size: 1.6rem;
  font-weight: 800;
  color: var(--text);
  margin-bottom: 30px;
  line-height: 1.3;
}

#answers {
  display: grid;
  gap: 16px;
  margin-bottom: 24px;
}

.answerWrapper {
  display: flex;
  gap: 10px;
}

.answerBtn {
  flex: 1;
  min-height: 68px;
  padding: 16px 20px;
  border: 2px solid var(--answer-border);
  border-radius: 20px;
  background: var(--answer);
  color: var(--text);
  font-size: 1.15rem;
  font-weight: 700;
  cursor: pointer;
  transition: all 0.2s;
  text-align: left;
  box-shadow: 0 4px 6px rgba(0,0,0,0.02);
  font-family: inherit;
}
.answerBtn:hover:not(:disabled) {
  border-color: var(--primary);
  background: #fff;
  transform: translateY(-2px);
  box-shadow: 0 6px 12px rgba(14, 165, 233, 0.1);
}
.answerBtn:active:not(:disabled) {
  transform: translateY(1px);
}

.answerBtn.correct {
  background: var(--correct);
  border-color: var(--correct-border);
  color: var(--green-dark);
  animation: bounce 0.4s ease;
}

.answerBtn.wrong {
  background: var(--wrong);
  border-color: var(--wrong-border);
  color: #b91c1c;
  animation: shake 0.4s ease;
}

.answerBtn:disabled {
  cursor: default;
  opacity: 0.8;
}

#feedback {
  min-height: 28px;
  font-weight: 800;
  font-size: 1.2rem;
  margin: 0 0 24px;
}
#feedback.success { color: var(--green-dark); }
#feedback.error { color: #b91c1c; }

/* Result Screen */
#resultText {
  font-size: 2rem;
  color: var(--primary-dark);
  margin-bottom: 10px;
}
#resultMessage {
  font-size: 1.2rem;
  color: var(--muted);
  margin-bottom: 30px;
  font-weight: 600;
}

.storyCounter {
  text-align: center;
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--muted);
  margin-bottom: 16px;
}

@media (min-width: 768px) {
  .storyButtons {
    flex-direction: row;
  }
  .filterBar {
    flex-direction: row;
    align-items: flex-start;
  }
  .filterGroup {
    flex: 1;
    align-items: flex-start;
  }
  .filterTabs {
    justify-content: flex-start;
  }
}