/* flashcards.css */
.flashcard-header {
    text-align: center;
    margin-bottom: 2rem;
    display: flex;
    flex-direction: column;
    align-items: center;
}

.flashcard-title {
    font-size: 2.25rem;
    font-weight: 800;
    color: #312e81; /* indigo-900 */
    margin-bottom: 0.25rem;
    margin-top: 0;
}

.flashcard-subtitle {
    color: #64748b; /* slate-500 */
    font-weight: 500;
    margin-top: 0;
}

.progress-container {
    width: 100%;
    max-width: 28rem;
    margin-top: 1.5rem;
}

.progress-labels {
    display: flex;
    justify-content: space-between;
    font-size: 0.875rem;
    font-weight: 600;
    color: #94a3b8; /* slate-400 */
    margin-bottom: 0.5rem;
}

.progress-track {
    height: 0.5rem;
    width: 100%;
    background-color: #e2e8f0; /* slate-200 */
    border-radius: 9999px;
    overflow: hidden;
}

.progress-fill {
    height: 100%;
    background-color: #6366f1; /* indigo-500 */
    border-radius: 9999px;
    transition: width 0.3s ease-out;
}

.flashcard-main {
    width: 100%;
    max-width: 28rem;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    align-items: center;
    perspective: 1200px;
}

.flashcard-3d-container {
    width: 100%;
    height: clamp(14rem, 45vw, 20rem);
    perspective: 1200px;
}

.flashcard-3d {
    position: relative;
    width: 100%;
    height: 100%;
    cursor: pointer;
    transform-style: preserve-3d;
    transition: transform 0.6s cubic-bezier(0.4, 0.2, 0.2, 1);
    border-radius: 1.5rem;
}

.flashcard-3d:hover {
    box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.25);
}

.flashcard-face-3d {
    position: absolute;
    inset: 0;
    border-radius: 1.5rem;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 2rem;
    backface-visibility: hidden;
}

.flashcard-front-3d {
    background-color: white;
    border: 2px solid #f1f5f9;
    box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
}

.flashcard-back-3d {
    background-color: #4f46e5; /* indigo-600 */
    border: 2px solid #6366f1; /* indigo-500 */
    color: white;
    transform: rotateY(180deg);
    box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
}

.card-lang-label {
    position: absolute;
    top: 1.5rem;
    left: 1.5rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    font-size: 0.75rem;
}

.flashcard-front-3d .card-lang-label {
    color: #cbd5e1; /* slate-300 */
}

.flashcard-back-3d .card-lang-label {
    color: #a5b4fc; /* indigo-300 */
}

.flashcard-face-3d h2 {
    font-size: clamp(1.4rem, 5vw, 2.8rem);
    font-weight: 700;
    text-align: center;
    line-height: 1.25;
    margin: 0;
    word-break: break-word;
    padding: 0 0.5rem;
}

.flashcard-front-3d h2 {
    color: #1e293b; /* slate-800 */
}

.card-instruction {
    position: absolute;
    bottom: 1.5rem;
    color: #94a3b8;
    font-size: 0.875rem;
    font-weight: 500;
}

.hint-section {
    height: 4rem;
    margin-top: 1.5rem;
    width: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
}

.hint-btn {
    color: #64748b;
    font-weight: 500;
    padding: 0.5rem 1rem;
    border-radius: 0.5rem;
    transition: color 0.2s;
    background: none;
    border: none;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 1rem;
}

.hint-btn:hover {
    color: #4f46e5;
}

.hint-display {
    background-color: #fef3c7; /* amber-100 */
    color: #78350f; /* amber-900 */
    border: 1px solid #fde68a; /* amber-200 */
    padding: 0.5rem 1.5rem;
    border-radius: 0.75rem;
    box-shadow: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    font-weight: 500;
    animation: fadeIn 0.3s ease-out;
}

.hidden {
    display: none !important;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(-5px); }
    to { opacity: 1; transform: translateY(0); }
}

.controls-section {
    width: 100%;
    max-width: 36rem;
    margin-top: 1rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
}

.control-btn {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 1rem;
    border-radius: 1rem;
    font-weight: 700;
    font-size: 1.125rem;
    transition: all 0.2s;
    cursor: pointer;
    border: none;
}

.control-btn#prev-btn {
    background-color: white;
    color: #334155;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    border: 1px solid #e2e8f0;
}

.control-btn#prev-btn:hover:not(.disabled) {
    box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    transform: translateY(-2px);
}

.control-btn.next-btn {
    background-color: #4f46e5;
    color: white;
    box-shadow: 0 4px 6px -1px rgba(99, 102, 241, 0.5);
}

.control-btn.next-btn:hover:not(.disabled) {
    background-color: #4338ca;
    box-shadow: 0 10px 15px -3px rgba(99, 102, 241, 0.5);
    transform: translateY(-2px);
}

.control-btn.disabled {
    background-color: #f1f5f9 !important;
    color: #94a3b8 !important;
    cursor: not-allowed !important;
    box-shadow: none !important;
    border: none !important;
    transform: none !important;
}

.utility-controls {
    display: flex;
    gap: 1.5rem;
    margin-top: 2rem;
}

.util-btn {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.875rem;
    font-weight: 600;
    color: #64748b;
    background: none;
    border: none;
    cursor: pointer;
    transition: color 0.2s;
}

.util-btn:hover {
    color: #4f46e5;
}

.util-btn svg {
    width: 18px;
    height: 18px;
}

/* --- Tracking UI & Compact Controls --- */
.compact-controls-container {
    display: flex;
    justify-content: flex-end;
    align-items: center;
    width: 100%;
    margin-top: 1rem;
}

.inline-nav-btn {
    background: white;
    border: 1px solid #e2e8f0;
    border-radius: 50%;
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    color: #475569;
    transition: all 0.2s ease;
}

.inline-nav-btn:hover:not(:disabled) {
    background: #f8fafc;
    color: #FE320A;
    border-color: #FE320A;
}

.inline-nav-btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.toggle-switch {
  position: relative;
  display: inline-block;
  width: 46px;
  height: 24px;
}
.toggle-switch input { 
  opacity: 0;
  width: 0;
  height: 0;
}
.slider {
  position: absolute;
  cursor: pointer;
  top: 0; left: 0; right: 0; bottom: 0;
  background-color: #cbd5e1;
  transition: .3s;
}
.slider:before {
  position: absolute;
  content: "";
  height: 18px;
  width: 18px;
  left: 3px;
  bottom: 3px;
  background-color: white;
  transition: .3s;
  box-shadow: 0 1px 3px rgba(0,0,0,0.2);
}
input:checked + .slider {
  background-color: #FE320A;
}
input:checked + .slider:before {
  transform: translateX(22px);
}
.slider.round {
  border-radius: 24px;
}
.slider.round:before {
  border-radius: 50%;
}

.learning-feedback-controls {
    z-index: 10;
}
.feedback-btn {
    padding: 0.6rem 1.2rem;
    border-radius: 20px;
    font-weight: 600;
    cursor: pointer;
    border: none;
    font-size: 0.95rem;
    transition: transform 0.15s, opacity 0.15s;
    box-shadow: 0 4px 6px rgba(0,0,0,0.05);
}
.needs-review-btn {
    background: #f1f5f9;
    color: #475569;
}
.got-it-btn {
    background: #FE320A;
    color: white;
}
.feedback-btn:hover {
    transform: translateY(-2px);

/* --- Tracking UI & Compact Controls --- */
.compact-controls-container {
    display: flex;
    justify-content: flex-end;
    align-items: center;
    width: 100%;
    margin-top: 1rem;
}

.inline-nav-btn {
    background: white;
    border: 1px solid #e2e8f0;
    border-radius: 50%;
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    color: #475569;
    transition: all 0.2s ease;
}

.inline-nav-btn:hover:not(:disabled) {
    background: #f8fafc;
    color: #FE320A;
    border-color: #FE320A;
}

.inline-nav-btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.toggle-switch {
  position: relative;
  display: inline-block;
  width: 46px;
  height: 24px;
}
.toggle-switch input { 
  opacity: 0;
  width: 0;
  height: 0;
}
.slider {
  position: absolute;
  cursor: pointer;
  top: 0; left: 0; right: 0; bottom: 0;
  background-color: #cbd5e1;
  transition: .3s;
}
.slider:before {
  position: absolute;
  content: "";
  height: 18px;
  width: 18px;
  left: 3px;
  bottom: 3px;
  background-color: white;
  transition: .3s;
  box-shadow: 0 1px 3px rgba(0,0,0,0.2);
}
input:checked + .slider {
  background-color: #FE320A;
}
input:checked + .slider:before {
  transform: translateX(22px);
}
.slider.round {
  border-radius: 24px;
}
.slider.round:before {
  border-radius: 50%;
}

.learning-feedback-controls {
    z-index: 10;
}
.feedback-btn {
    padding: 0.6rem 1.2rem;
    border-radius: 20px;
    font-weight: 600;
    cursor: pointer;
    border: none;
    font-size: 0.95rem;
    transition: transform 0.15s, opacity 0.15s;
    box-shadow: 0 4px 6px rgba(0,0,0,0.05);
}
.needs-review-btn {
    background: #f1f5f9;
    color: #475569;
}
.got-it-btn {
    background: #FE320A;
    color: white;
}
.feedback-btn:hover {
    transform: translateY(-2px);
}
.feedback-btn:active {
    transform: translateY(0);
}

.card-icon-btn {
    background: transparent;
    border: none;
    color: #cbd5e1;
    cursor: pointer;
    transition: color 0.2s;
    padding: 8px;
}
.card-icon-btn:hover {
    color: #FE320A;
}

/* ===== MOBILE RESPONSIVE FLASHCARDS ===== */
@media (max-width: 768px) {
    .flashcard-main {
        max-width: 100%;
        padding: 0 0.25rem;
    }

    .flashcard-3d-container {
        height: clamp(13rem, 50vw, 18rem);
    }

    .flashcard-face-3d {
        padding: 1rem;
    }

    .card-lang-label {
        top: 0.75rem;
        left: 0.75rem;
        font-size: 0.65rem;
    }

    .card-instruction {
        bottom: 0.75rem;
        font-size: 0.75rem;
        text-align: center;
        padding: 0 2rem;
    }

    .card-icon-btn {
        bottom: 8px !important;
        padding: 6px;
    }

    .hint-section {
        margin-top: 0.75rem;
        height: auto;
        min-height: 3rem;
    }

    .compact-controls-container {
        flex-direction: row !important;
        flex-wrap: wrap !important;
        justify-content: space-between !important;
        gap: 0.75rem !important;
    }

    .feedback-btn {
        padding: 0.5rem 0.9rem;
        font-size: 0.85rem;
    }

    .flashcard-title {
        font-size: 1.6rem;
    }

    .flashcard-subtitle {
        font-size: 0.85rem;
    }

    .inline-nav-btn {
        width: 36px;
        height: 36px;
    }

    .toggle-switch {
        width: 40px;
        height: 21px;
    }
}

@media (max-width: 480px) {
    .flashcard-3d-container {
        height: clamp(12rem, 55vw, 16rem);
    }

    .flashcard-face-3d h2 {
        font-size: clamp(1.2rem, 6vw, 2rem);
    }

    .learning-feedback-controls {
        gap: 0.5rem !important;
    }

    .flashcard-header {
        padding: 0 0.5rem;
    }
}