:root {
  --board: #24402f;
  --board-dark: #17281c;
  --chalk: #f4f1e8;
  --chalk-dim: #cdd6c9;
  --chalk-yellow: #f2c94c;
  --chalk-coral: #ff8b6b;
  --wood: #6b4a34;
  --wood-dark: #493022;
}

.kk-app {
  font-family: 'Inter', sans-serif;
  min-height: 100vh;
  background: radial-gradient(ellipse at top, var(--board) 0%, var(--board-dark) 100%);
  color: var(--chalk);
  padding: 0 0 3rem 0;
  box-sizing: border-box;
}

.kk-app *, .kk-app *::before, .kk-app *::after { 
  box-sizing: border-box; 
}

.kk-hero {
  text-align: center;
  padding: 2.5rem 1.5rem 1.5rem;
  border-bottom: 10px solid var(--wood);
  box-shadow: 0 6px 0 var(--wood-dark);
  position: relative;
}

.kk-title {
  font-family: 'Kalam', cursive;
  font-weight: 700;
  font-size: clamp(2.2rem, 6vw, 3.2rem);
  margin: 0;
  letter-spacing: 0.02em;
  text-shadow: 0 0 18px rgba(244,241,232,0.25);
}

.kk-subtitle {
  margin: 0.5rem auto 0;
  max-width: 34rem;
  color: var(--chalk-dim);
  font-size: 0.98rem;
}

.kk-progress-overall {
  margin-top: 1rem;
  font-family: 'Kalam', cursive;
  font-size: 1.05rem;
  color: var(--chalk-yellow);
}

.kk-tabs {
  display: flex;
  gap: 0.6rem;
  overflow-x: auto;
  padding: 1.25rem 1.5rem 0.5rem;
  max-width: 56rem;
  margin: 0 auto;
}

.kk-tab {
  flex: 0 0 auto;
  font-family: 'Kalam', cursive;
  font-size: 1rem;
  background: transparent;
  border: 2px dashed var(--chalk-dim);
  color: var(--chalk-dim);
  border-radius: 10px;
  padding: 0.5rem 0.9rem;
  cursor: pointer;
  transition: transform 0.15s ease, color 0.15s ease, border-color 0.15s ease;
}

.kk-tab:hover { color: var(--chalk); border-color: var(--chalk); }
.kk-tab:focus-visible { outline: 2px solid var(--chalk-yellow); outline-offset: 2px; }

.kk-tab.active {
  color: var(--board-dark);
  background: var(--chalk-yellow);
  border-color: var(--chalk-yellow);
  border-style: solid;
  transform: rotate(-1deg);
}

.kk-main {
  max-width: 40rem;
  margin: 1rem auto 0;
  padding: 1.25rem 1.5rem 0;
}

.kk-cat-progress {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.85rem;
  color: var(--chalk-dim);
  margin-bottom: 0.6rem;
  font-family: 'Inter', sans-serif;
}

.kk-bar {
  height: 6px;
  background: rgba(244,241,232,0.15);
  border-radius: 4px;
  overflow: hidden;
  margin: 0 0 1rem;
}

.kk-bar-fill {
  height: 100%;
  background: var(--chalk-yellow);
  transition: width 0.3s ease;
}

.kk-stage {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.kk-nav-btn {
  background: var(--wood);
  border: none;
  color: var(--chalk);
  width: 2.6rem;
  height: 2.6rem;
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  flex: 0 0 auto;
  box-shadow: 0 3px 0 var(--wood-dark);
  transition: transform 0.1s ease;
}

.kk-nav-btn:hover { transform: translateY(1px); }
.kk-nav-btn:active { transform: translateY(3px); box-shadow: none; }
.kk-nav-btn:focus-visible { outline: 2px solid var(--chalk-yellow); outline-offset: 2px; }

.kk-card-wrap {
  flex: 1;
  perspective: 1400px;
  position: relative;
}

.kk-dust {
  position: absolute;
  inset: 0;
  pointer-events: none;
}

.kk-dust span {
  position: absolute;
  bottom: 0.5rem;
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: var(--chalk);
  opacity: 0;
}

.kk-app.dust-on .kk-dust span {
  animation: kk-fall 0.5s ease-out forwards;
}

@keyframes kk-fall {
  0% { opacity: 0.9; transform: translateY(0); }
  100% { opacity: 0; transform: translateY(18px); }
}

.kk-flashcard {
  height: 15rem;
  cursor: pointer;
  transform-style: preserve-3d;
  transition: transform 0.5s cubic-bezier(0.4,0.2,0.2,1);
  position: relative;
  outline: none;
}

.kk-flashcard.flipped { transform: rotateY(180deg); }

.kk-face {
  position: absolute;
  inset: 0;
  backface-visibility: hidden;
  border-radius: 14px;
  border: 3px solid var(--wood);
  background: linear-gradient(160deg, rgba(244,241,232,0.06), rgba(244,241,232,0.01));
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 1.5rem;
}

.kk-face.back { transform: rotateY(180deg); }
.kk-emoji { font-size: 2.6rem; margin-bottom: 0.5rem; }

.kk-word-en {
  font-family: 'Kalam', cursive;
  font-size: clamp(1.8rem, 5vw, 2.4rem);
  margin: 0.2rem 0;
}

.kk-hint { font-size: 0.8rem; color: var(--chalk-dim); margin-top: 0.6rem; }

.kk-word-id {
  font-family: 'Kalam', cursive;
  color: var(--chalk-yellow);
  font-size: 1.8rem;
  margin: 0 0 0.8rem;
}

.kk-example-en { font-style: italic; margin: 0.2rem 0; }
.kk-example-id { color: var(--chalk-dim); margin: 0.2rem 0; font-size: 0.9rem; }

.kk-actions {
  display: flex;
  gap: 0.75rem;
  justify-content: center;
  margin-top: 1.25rem;
  flex-wrap: wrap;
}

.kk-action-btn {
  font-family: 'Inter', sans-serif;
  font-weight: 600;
  font-size: 0.88rem;
  border-radius: 999px;
  padding: 0.55rem 1.1rem;
  border: 2px solid var(--chalk-dim);
  background: transparent;
  color: var(--chalk);
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  transition: all 0.15s ease;
}

.kk-action-btn:hover { border-color: var(--chalk); }
.kk-action-btn:focus-visible { outline: 2px solid var(--chalk-yellow); outline-offset: 2px; }

.kk-action-btn.learned {
  background: var(--chalk-coral);
  border-color: var(--chalk-coral);
  color: var(--board-dark);
}

.kk-grid-title {
  font-family: 'Kalam', cursive;
  font-size: 1.1rem;
  margin: 2rem 0 0.75rem;
  color: var(--chalk-dim);
}

.kk-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(7.5rem, 1fr));
  gap: 0.6rem;
}

.kk-mini {
  background: rgba(244,241,232,0.05);
  border: 1px solid rgba(244,241,232,0.15);
  border-radius: 8px;
  padding: 0.5rem 0.6rem;
  text-align: left;
  color: var(--chalk);
  cursor: pointer;
  font-size: 0.85rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.3rem;
}

.kk-mini:hover { border-color: var(--chalk-yellow); }
.kk-mini:focus-visible { outline: 2px solid var(--chalk-yellow); outline-offset: 2px; }
.kk-mini.current { border-color: var(--chalk-yellow); background: rgba(242,201,76,0.1); }
.kk-mini .kk-check { color: var(--chalk-yellow); flex: 0 0 auto; display: inline-flex; align-items: center; }

@media (prefers-reduced-motion: reduce) {
  .kk-flashcard, .kk-nav-btn, .kk-action-btn { transition: none !important; }
  .kk-app.dust-on .kk-dust span { animation: none !important; }
}

@media (max-width: 480px) {
  .kk-flashcard { height: 17rem; }
  .kk-stage { gap: 0.4rem; }
}