* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 20px;
}

.container {
    background: white;
    border-radius: 20px;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
    width: 100%;
    max-width: 800px;
    padding: 40px;
}

header {
    text-align: center;
    margin-bottom: 40px;
}

header h1 {
    font-size: 2.5rem;
    color: #333;
    margin-bottom: 10px;
}

.subtitle {
    color: #666;
    font-size: 1.1rem;
}

/* 上传区域 */
.upload-section {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 20px;
}

.upload-area {
    width: 100%;
    padding: 60px 20px;
    border: 3px dashed #ccc;
    border-radius: 15px;
    text-align: center;
    cursor: pointer;
    transition: all 0.3s ease;
    background: #f9f9f9;
}

.upload-area:hover {
    border-color: #667eea;
    background: #f0f4ff;
}

.upload-area.dragover {
    border-color: #667eea;
    background: #e8eeff;
    transform: scale(1.02);
}

.upload-icon {
    font-size: 4rem;
    margin-bottom: 15px;
}

.upload-hint {
    color: #999;
    font-size: 0.9rem;
    margin-top: 10px;
}

/* 按钮 */
.btn-primary, .btn-secondary {
    padding: 15px 40px;
    border-radius: 10px;
    font-size: 1rem;
    cursor: pointer;
    transition: all 0.3s ease;
    border: none;
}

.btn-primary {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 20px rgba(102, 126, 234, 0.4);
}

.btn-secondary {
    background: #f5f5f5;
    color: #333;
}

.btn-secondary:hover {
    background: #e8e8e8;
}

/* 预览区域 */
.preview-section {
    margin-top: 30px;
}

.comparison-container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 20px;
    margin-bottom: 30px;
}

.comparison-item {
    position: relative;
}

.comparison-item .label {
    position: absolute;
    top: 10px;
    left: 10px;
    background: rgba(0, 0, 0, 0.6);
    color: white;
    padding: 5px 12px;
    border-radius: 5px;
    font-size: 0.9rem;
}

.comparison-item img {
    width: 100%;
    border-radius: 10px;
    display: block;
}

/* 加载动画 */
.loading-overlay {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(255, 255, 255, 0.9);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    border-radius: 10px;
}

.spinner {
    width: 50px;
    height: 50px;
    border: 4px solid #f3f3f3;
    border-top: 4px solid #667eea;
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

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

.action-buttons {
    display: flex;
    justify-content: center;
    gap: 15px;
}

footer {
    text-align: center;
    margin-top: 40px;
    color: #999;
    font-size: 0.9rem;
}

/* 响应式 */
@media (max-width: 600px) {
    .container {
        padding: 20px;
    }

    header h1 {
        font-size: 1.8rem;
    }

    .comparison-container {
        grid-template-columns: 1fr;
    }

    .action-buttons {
        flex-direction: column;
    }

    .btn-primary, .btn-secondary {
        width: 100%;
    }
}