.quiz-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 20px;
    margin: 0;
    width: 100%;
}

.quiz-card {
    position: relative;
    background: white;
    border-radius: 16px;
    overflow: hidden;
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.06);
    border: 1px solid rgba(0, 0, 0, 0.06);
    display: flex;
    flex-direction: column;
    height: 100%;
    min-height: 240px;
    animation: cardFadeIn 0.4s ease-out both;
}

.quiz-card:nth-child(1) { animation-delay: 0.05s; }
.quiz-card:nth-child(2) { animation-delay: 0.1s; }
.quiz-card:nth-child(3) { animation-delay: 0.15s; }
.quiz-card:nth-child(4) { animation-delay: 0.2s; }
.quiz-card:nth-child(5) { animation-delay: 0.25s; }
.quiz-card:nth-child(6) { animation-delay: 0.3s; }
.quiz-card:nth-child(n+7) { animation-delay: 0.35s; }

@keyframes cardFadeIn {
    from {
        opacity: 0;
        transform: translateY(16px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.quiz-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 12px 24px rgba(0, 0, 0, 0.1);
    border-color: transparent;
}

.quiz-card-accent {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: var(--card-gradient, linear-gradient(135deg, #0d9488 0%, #14b8a6 100%));
}

.quiz-card-badge {
    padding: 3px 10px;
    background: linear-gradient(135deg, #f59e0b 0%, #fbbf24 100%);
    color: white;
    font-size: 0.7rem;
    font-weight: 700;
    border-radius: 12px;
    box-shadow: 0 2px 6px rgba(245, 158, 11, 0.35);
    letter-spacing: 0.02em;
}

.quiz-card-locked {
    opacity: 0.95;
}

.quiz-card-locked:hover {
    transform: translateY(-3px);
    box-shadow: 0 8px 16px rgba(0, 0, 0, 0.08);
}

.quiz-card-body {
    padding: 20px;
    display: flex;
    flex-direction: column;
    flex: 1;
    position: relative;
    z-index: 1;
}

.quiz-card-header {
    display: flex;
    align-items: flex-start;
    justify-content: space-between;
    margin-bottom: 14px;
}

.quiz-card-icon {
    width: 48px;
    height: 48px;
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 26px;
    background: linear-gradient(135deg, rgba(0, 0, 0, 0.03) 0%, rgba(0, 0, 0, 0.01) 100%);
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    flex-shrink: 0;
}

.quiz-card:hover .quiz-card-icon {
    transform: scale(1.08) rotate(-3deg);
}

.quiz-card-meta {
    display: flex;
    flex-direction: column;
    align-items: flex-end;
    gap: 6px;
}

.quiz-card-tag {
    padding: 3px 8px;
    border-radius: 10px;
    font-size: 0.65rem;
    font-weight: 600;
    white-space: nowrap;
    letter-spacing: 0.02em;
}

.quiz-card-tag-success {
    background: rgba(16, 185, 129, 0.1);
    color: #059669;
}

.quiz-card-tag-locked {
    background: rgba(100, 116, 139, 0.08);
    color: #64748b;
}

.quiz-card-title {
    font-size: 1.05rem;
    font-weight: 700;
    color: var(--text-primary);
    line-height: 1.4;
    margin: 0 0 8px 0;
    letter-spacing: -0.01em;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.quiz-card-desc {
    font-size: 0.85rem;
    color: var(--text-secondary);
    line-height: 1.6;
    margin: 0 0 16px 0;
    flex: 1;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.quiz-card-footer {
    margin-top: auto;
    padding-top: 14px;
    border-top: 1px solid rgba(0, 0, 0, 0.05);
}

.quiz-card-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 6px;
    width: 100%;
    padding: 10px 16px;
    font-size: 0.85rem;
    font-weight: 600;
    color: white;
    background: var(--card-gradient, linear-gradient(135deg, #0d9488 0%, #14b8a6 100%));
    border: none;
    border-radius: 10px;
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    position: relative;
    overflow: hidden;
}

.quiz-card-btn::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.2), transparent);
    transition: left 0.4s ease;
}

.quiz-card-btn:hover {
    transform: translateY(-1px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
}

.quiz-card-btn:hover::before {
    left: 100%;
}

.quiz-card-btn:active {
    transform: translateY(0);
}

.quiz-card-btn-locked {
    background: #f1f5f9;
    color: #64748b;
}

.quiz-card-btn-locked:hover {
    background: #e2e8f0;
    color: #475569;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.06);
}

.quiz-empty {
    text-align: center;
    padding: 60px 24px;
    animation: fadeIn 0.4s ease-out;
}

.quiz-empty-icon {
    font-size: 4rem;
    margin-bottom: 16px;
    opacity: 0.25;
}

.quiz-empty-text {
    color: var(--text-secondary);
    font-size: 0.95rem;
}

.quiz-loading {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 60px 24px;
    gap: 16px;
}

.quiz-loading-spinner {
    width: 40px;
    height: 40px;
    border: 3px solid rgba(0, 0, 0, 0.08);
    border-top-color: var(--primary-color, #0d9488);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

@keyframes spin {
    to {
        transform: rotate(360deg);
    }
}

.quiz-loading-text {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

@media (max-width: 640px) {
    .quiz-grid {
        grid-template-columns: 1fr;
        gap: 12px;
    }
    
    .quiz-card {
        min-height: 200px;
        border-radius: 14px;
    }
    
    .quiz-card-body {
        padding: 16px;
    }
    
    .quiz-card-header {
        margin-bottom: 12px;
    }
    
    .quiz-card-icon {
        width: 42px;
        height: 42px;
        font-size: 22px;
        border-radius: 10px;
    }
    
    .quiz-card-title {
        font-size: 1rem;
        margin-bottom: 6px;
    }
    
    .quiz-card-desc {
        font-size: 0.82rem;
        margin-bottom: 12px;
    }
    
    .quiz-card-footer {
        padding-top: 12px;
    }
    
    .quiz-card-btn {
        padding: 9px 14px;
        font-size: 0.82rem;
        border-radius: 8px;
    }
    
    .quiz-card-badge {
        padding: 2px 8px;
        font-size: 0.65rem;
    }
    
    .quiz-card-tag {
        padding: 2px 6px;
        font-size: 0.6rem;
    }
    
    .quiz-empty,
    .quiz-loading {
        padding: 40px 16px;
    }
    
    .quiz-empty-icon {
        font-size: 3rem;
        margin-bottom: 12px;
    }
    
    .quiz-empty-text {
        font-size: 0.9rem;
    }
    
    .quiz-loading-spinner {
        width: 36px;
        height: 36px;
    }
    
    .quiz-loading-text {
        font-size: 0.85rem;
    }
}

@media (max-width: 480px) {
    .quiz-grid {
        gap: 10px;
    }
    
    .quiz-card {
        min-height: 180px;
        border-radius: 12px;
    }
    
    .quiz-card-body {
        padding: 14px;
    }
    
    .quiz-card-icon {
        width: 38px;
        height: 38px;
        font-size: 20px;
        border-radius: 8px;
    }
    
    .quiz-card-title {
        font-size: 0.95rem;
    }
    
    .quiz-card-desc {
        font-size: 0.78rem;
        -webkit-line-clamp: 2;
        line-clamp: 2;
    }
    
    .quiz-card-btn {
        padding: 8px 12px;
        font-size: 0.78rem;
        border-radius: 8px;
    }
    
    .quiz-empty,
    .quiz-loading {
        padding: 32px 12px;
    }
    
    .quiz-empty-icon {
        font-size: 2.5rem;
    }
    
    .quiz-empty-text {
        font-size: 0.85rem;
    }
}

@media (min-width: 641px) and (max-width: 900px) {
    .quiz-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 18px;
    }
}

@media (min-width: 901px) and (max-width: 1200px) {
    .quiz-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 20px;
    }
}

@media (min-width: 1201px) {
    .quiz-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 24px;
    }
}

@media (prefers-reduced-motion: reduce) {
    .quiz-card,
    .quiz-loading-spinner {
        animation: none;
    }
    
    .quiz-card-btn::before {
        display: none;
    }
}