/* Button Styles */
.theme-toggle-btn {
  background: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 0.5rem 0.75rem;
  cursor: pointer;
  font-size: 1.25rem;
  transition: all var(--transition-duration) ease;
  display: flex;
  align-items: center;
  justify-content: center;
}

.theme-toggle-btn:hover {
  background-color: var(--border-color);
  transform: scale(1.05);
}

.theme-toggle-btn:active {
  transform: scale(0.98);
}

.theme-icon {
  line-height: 1;
}

/* Loading & Animation */
.loading {
  display: inline-block;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background-color: currentColor;
  animation: pulse 1.5s infinite;
}

@keyframes pulse {
  0%, 100% {
    opacity: 0.3;
  }
  50% {
    opacity: 1;
  }
}

@keyframes fadeIn {
  from {
    opacity: 0;
  }
  to {
    opacity: 1;
  }
}

/* Responsive */
@media (max-width: 1200px) {
  .vocab-list {
    grid-template-columns: repeat(4, 1fr);
  }
}

@media (max-width: 992px) {
  .vocab-list {
    grid-template-columns: repeat(3, 1fr);
  }
}

@media (max-width: 768px) {
  .hangul-card {
    max-width: 100%;
  }

  .hangul-char {
    font-size: 3.5rem;
  }

  .hangul-tabs {
    gap: 0.25rem;
  }

  .hangul-tab {
    padding: 0.5rem 1rem;
    font-size: 0.9rem;
  }

  .vocab-list {
    grid-template-columns: repeat(2, 1fr);
  }

  .vocab-card {
    min-height: 180px;
  }

  .flashcard-wrapper {
    max-width: 100%;
  }

  .flashcard {
    font-size: 2.5rem;
  }

  .flashcard-controls {
    flex-direction: column;
  }

  .btn-know, .btn-dont-know, .btn-speak, .btn-next, .btn-prev {
    width: 100%;
  }

  .vocab-category-tabs {
    overflow-x: auto;
  }

  .vocab-category-btn {
    white-space: nowrap;
  }

  .modal-content {
    padding: 1.5rem;
    max-width: 95%;
  }
}

@media (max-width: 480px) {
  .hangul-char {
    font-size: 3rem;
  }

  .vocab-list {
    grid-template-columns: 1fr;
  }

  .flashcard {
    font-size: 2rem;
  }

  .menu-card {
    padding: 1.25rem;
    gap: 0.75rem;
  }

  .menu-icon {
    font-size: 2.5rem;
  }
}

/* 다크 테마 전용 - 음성/Play/Know 버튼 보라색 */
[data-theme="dark"] .btn-speak,
[data-theme="dark"] .vocab-play-btn,
[data-theme="dark"] .grammar-speak-btn,
[data-theme="dark"] .btn-know {
  background-color: var(--accent-primary) !important;
  color: #fff;
}

[data-theme="dark"] .btn-speak:hover,
[data-theme="dark"] .vocab-play-btn:hover,
[data-theme="dark"] .grammar-speak-btn:hover,
[data-theme="dark"] .btn-know:hover {
  background-color: var(--accent-primary) !important;
  opacity: 0.9;
}

/* Discord link: show on desktop, hide on mobile/tablet */
.sidebar-discord-link { display: block; }

@media (max-width: 1023px) {
  .sidebar-discord-link { display: none; }
}