/**
 * Avatar Fallback Styles
 * CSS cho avatar mặc định và fallback
 */

/* Avatar fallback styling */
.avatar-fallback {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-weight: bold;
    font-size: 1.2em;
    text-transform: uppercase;
    position: relative;
    overflow: hidden;
}

/* Animation cho avatar fallback */
.avatar-fallback::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255,255,255,0.2), transparent);
    animation: shimmer 2s infinite;
}

@keyframes shimmer {
    0% {
        left: -100%;
    }
    100% {
        left: 100%;
    }
}

/* Avatar preview với fallback */
.avatar-preview img.avatar-fallback {
    width: 100%;
    height: 100%;
    object-fit: cover;
    border-radius: 50%;
}

/* Avatar trong header/navigation */
.avatar img.avatar-fallback {
    border: 2px solid #e9ecef;
    transition: all 0.3s ease;
}

.avatar img.avatar-fallback:hover {
    border-color: #007bff;
    transform: scale(1.05);
}

/* Avatar trong danh sách */
.list-item .avatar img.avatar-fallback,
.user-item .avatar img.avatar-fallback {
    border: 1px solid #dee2e6;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

/* Avatar trong profile */
.profile-avatar img.avatar-fallback {
    border: 3px solid #fff;
    box-shadow: 0 4px 8px rgba(0,0,0,0.15);
}

/* Loading state cho avatar */
.avatar-loading {
    background: #f8f9fa;
    border: 2px dashed #dee2e6;
    display: flex;
    align-items: center;
    justify-content: center;
    color: #6c757d;
    font-size: 0.9em;
}

.avatar-loading::after {
    content: '';
    width: 20px;
    height: 20px;
    border: 2px solid #dee2e6;
    border-top: 2px solid #007bff;
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

/* Responsive avatar fallback */
@media (max-width: 768px) {
    .avatar-fallback {
        font-size: 1em;
    }
    
    .avatar-preview img.avatar-fallback {
        width: 80px;
        height: 80px;
    }
}

@media (max-width: 480px) {
    .avatar-preview img.avatar-fallback {
        width: 60px;
        height: 60px;
    }
    
    .avatar-fallback {
        font-size: 0.8em;
    }
}

/* Dark mode support */
@media (prefers-color-scheme: dark) {
    .avatar-fallback {
        background: linear-gradient(135deg, #4a5568 0%, #2d3748 100%);
        color: #e2e8f0;
    }
    
    .avatar img.avatar-fallback {
        border-color: #4a5568;
    }
    
    .avatar img.avatar-fallback:hover {
        border-color: #63b3ed;
    }
}

/* High contrast mode */
@media (prefers-contrast: high) {
    .avatar-fallback {
        border: 2px solid #000;
    }
    
    .avatar img.avatar-fallback {
        border-width: 3px;
    }
}

/* Reduced motion support */
@media (prefers-reduced-motion: reduce) {
    .avatar-fallback::before {
        animation: none;
    }
    
    .avatar-loading::after {
        animation: none;
    }
    
    .avatar img.avatar-fallback:hover {
        transform: none;
    }
}