.alphabet-module {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-lg);
}

.category-tabs {
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-3);
    justify-content: center;
    margin-bottom: var(--space-6);
    padding: var(--space-4);
    background: rgba(255, 255, 255, 0.3);
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
    border-radius: var(--radius-2xl);
    box-shadow: var(--shadow-sm);
}

.alphabet-card {
    aspect-ratio: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    background: var(--color-cream-base);
    border: 3px solid var(--color-cream-dark);
    border-radius: var(--radius-xl);
    cursor: pointer;
    transition: var(--transition-bounce);
    position: relative;
    min-height: 120px;
    padding: var(--space-4);
    z-index: 1;
    box-shadow: var(--shadow-sm);
}

.alphabet-card:hover {
    border-color: var(--color-orange-vivid);
    background: var(--color-white);
    transform: translateY(-4px) scale(1.05);
    box-shadow: var(--shadow-md), var(--shadow-orange);
    z-index: 10;
}

.alphabet-card.completed {
    border-color: var(--color-green-meadow);
    background: linear-gradient(135deg, var(--color-green-soft) 0%, var(--color-green-light) 100%);
    z-index: 2;
}

.alphabet-card .completed-badge {
    position: absolute;
    top: 8px;
    right: 8px;
    color: var(--color-green-forest);
    font-size: var(--font-size-lg);
    z-index: 3;
    pointer-events: none;
    background: var(--color-white);
    border-radius: var(--radius-full);
    width: 28px;
    height: 28px;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: var(--shadow-sm);
}

.alphabet-card .letter-bengali {
    font-family: var(--font-family-bengali);
    font-size: var(--font-size-4xl);
    font-weight: var(--font-weight-bold);
    color: var(--color-charcoal);
}

.alphabet-card .letter-transliteration {
    font-family: var(--font-family-ui);
    font-size: var(--font-size-sm);
    font-weight: var(--font-weight-medium);
    color: var(--color-gray-700);
    margin-top: var(--space-2);
}

/* Letter Detail Panel */
.letter-detail-panel {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    background-color: var(--color-white);
    border-radius: var(--radius-xl) var(--radius-xl) 0 0;
    box-shadow: var(--shadow-xl);
    padding: var(--spacing-xl);
    z-index: 200;
    max-height: 60vh;
    overflow-y: auto;
}

.letter-detail-panel .close-btn {
    position: absolute;
    top: var(--spacing-md);
    right: var(--spacing-md);
    width: 32px;
    height: 32px;
    border-radius: var(--radius-full);
    background-color: var(--color-gray-100);
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.letter-detail-panel .close-btn:hover {
    background-color: var(--color-gray-200);
}

.letter-display {
    text-align: center;
    margin-bottom: var(--spacing-lg);
}

.letter-large {
    font-family: var(--font-family-bengali);
    font-size: 5rem;
    color: #aa846e;
    line-height: 1;
}

.letter-info {
    margin-bottom: var(--spacing-lg);
}

.info-row {
    display: flex;
    justify-content: space-between;
    padding: var(--spacing-sm) 0;
    border-bottom: 1px solid var(--color-gray-100);
}

.info-row:last-child {
    border-bottom: none;
}

.info-label {
    font-weight: var(--font-weight-medium);
    color: var(--color-gray-600);
}

.info-value {
    color: #aa846e;
}

.letter-actions {
    display: flex;
    gap: var(--spacing-md);
    justify-content: center;
    flex-wrap: wrap;
}

/* Module Progress */
.module-progress {
    margin-top: var(--space-8);
    padding: var(--space-6);
    background-color: var(--color-white);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-sm);
}

.module-progress .progress-info {
    margin-bottom: var(--space-3);
    text-align: center;
    font-family: var(--font-family-display);
    font-size: var(--font-size-base);
    font-weight: var(--font-weight-semibold);
    color: var(--color-charcoal);
}

/* ============================================