:root {
    --primary-color: #0066ff;
    --primary-hover: #0052cc;
    --background: #f5f7fa;
    --card-background: #ffffff;
    --text-primary: #2c3e50;
    --text-secondary: #666666;
    --border-radius: 12px;
    --shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    --transition: all 0.3s ease;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
    background: var(--background);
    color: var(--text-primary);
    line-height: 1.6;
    padding: 20px;
}

.app {
    max-width: 1200px;
    margin: 0 auto;
}

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

.header h1 {
    font-size: 2.5rem;
    color: var(--text-primary);
    margin-bottom: 8px;
}

.subtitle {
    color: var(--text-secondary);
    font-size: 1.1rem;
}

.card {
    background: var(--card-background);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    margin-bottom: 24px;
    overflow: hidden;
    transition: var(--transition);
}

.card:hover {
    box-shadow: 0 6px 12px rgba(0, 0, 0, 0.15);
}

.card-content {
    padding: 24px;
}

.upload-area {
    border: 2px dashed #ddd;
    border-radius: var(--border-radius);
    padding: 40px 20px;
    text-align: center;
    cursor: pointer;
    transition: var(--transition);
}

.upload-area:hover {
    border-color: var(--primary-color);
    background: rgba(0, 102, 255, 0.02);
}

.upload-icon {
    width: 64px;
    height: 64px;
    margin: 0 auto 16px;
    background: url('upload-icon.svg') no-repeat center;
    background-size: contain;
}

.btn {
    padding: 12px 24px;
    border: none;
    border-radius: var(--border-radius);
    font-size: 1rem;
    cursor: pointer;
    transition: var(--transition);
}

.btn.primary {
    background: var(--primary-color);
    color: white;
}

.btn.primary:hover {
    background: var(--primary-hover);
}

.settings-group {
    margin-bottom: 20px;
}

.settings-group label {
    display: block;
    margin-bottom: 8px;
    color: var(--text-secondary);
}

.quality-slider {
    width: 100%;
    height: 6px;
    background: #eee;
    border-radius: 3px;
    outline: none;
    -webkit-appearance: none;
    margin: 15px 0;
}

.quality-slider::-webkit-slider-thumb {
    -webkit-appearance: none;
    width: 18px;
    height: 18px;
    background: white;
    border: 2px solid var(--primary-color);
    border-radius: 50%;
    cursor: pointer;
    box-shadow: 0 1px 3px rgba(0,0,0,0.2);
    transition: var(--transition);
}

.quality-slider::-webkit-slider-thumb:hover {
    transform: scale(1.1);
    box-shadow: 0 2px 5px rgba(0,0,0,0.3);
}

.size-select {
    width: 100%;
    padding: 8px;
    border: 1px solid #ddd;
    border-radius: var(--border-radius);
    font-size: 1rem;
}

.preview-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 24px;
}

.preview-item {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.preview-image {
    position: relative;
    width: 100%;
    height: 400px;
    background: #f8f9fa;
    display: flex;
    align-items: center;
    justify-content: center;
    border: 1px solid #eee;
    border-radius: var(--border-radius);
    overflow: hidden;
}

.preview-image::before {
    content: attr(data-placeholder);
    color: var(--text-secondary);
    font-size: 0.9rem;
    position: absolute;
    z-index: 1;
}

.preview-image img {
    position: relative;
    z-index: 2;
    max-width: 100%;
    max-height: 100%;
    width: auto;
    height: auto;
    display: none;
    transition: opacity 0.3s ease;
    object-fit: contain;
}

.preview-image img.active {
    display: block;
}

.preview-card {
    display: none;
}

.preview-card.active {
    display: block;
    animation: fadeIn 0.3s ease;
}

@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

.image-info {
    color: var(--text-secondary);
    margin: 8px 0;
}

.loading {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(255, 255, 255, 0.9);
    display: none;
    justify-content: center;
    align-items: center;
    flex-direction: column;
    z-index: 1000;
}

.loading-spinner {
    width: 40px;
    height: 40px;
    border: 3px solid #f3f3f3;
    border-top: 3px solid var(--primary-color);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin-bottom: 12px;
}

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

.toast {
    position: fixed;
    top: 24px;
    left: 50%;
    transform: translateX(-50%);
    background: rgba(0, 0, 0, 0.8);
    color: white;
    padding: 12px 24px;
    border-radius: var(--border-radius);
    display: none;
    z-index: 1001;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
    animation: slideDown 0.3s ease;
    font-weight: 500;
    min-width: 200px;
    text-align: center;
}

@keyframes slideDown {
    from {
        transform: translate(-50%, -100%);
        opacity: 0;
    }
    to {
        transform: translate(-50%, 0);
        opacity: 1;
    }
}

.toast:hover {
    background: rgba(0, 0, 0, 0.9);
}

@media (max-width: 768px) {
    .preview-grid {
        grid-template-columns: 1fr;
    }
    
    .card-content {
        padding: 16px;
    }
    
    .header h1 {
        font-size: 2rem;
    }
}

/* 上传区域基础样式 */
.upload-card {
    transition: all 0.3s ease;
}

.upload-card.collapsed {
    margin-bottom: 16px;
    background: var(--background);
}

.upload-card.collapsed .card-content {
    padding: 8px;
}

/* 完整上传区域 */
.upload-area.full {
    height: 200px;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    gap: 16px;
    padding: 20px;
    border: 2px dashed #ddd;
    border-radius: var(--border-radius);
    transition: all 0.3s ease;
    cursor: pointer;
}

.upload-area.full:hover {
    border-color: var(--primary-color);
    background: rgba(0, 102, 255, 0.02);
}

/* 上传图标样式优化 */
.upload-icon {
    width: 48px;
    height: 48px;
    margin: 0;
    background: url('upload-icon.svg') no-repeat center;
    background-size: contain;
}

/* 上传区域文字样式 */
.upload-area.full p {
    margin: 0;
    color: var(--text-secondary);
    font-size: 1rem;
}

/* 上传按钮样式优化 */
.upload-area.full .btn {
    margin: 0;
    padding: 10px 20px;
    font-size: 0.95rem;
}

/* 折叠后的简化上传区域 */
.upload-area.compact {
    display: none;
    height: 48px;
    padding: 8px 16px;
    flex-direction: row;
    justify-content: center;
    align-items: center;
    background: var(--background);
    border: none;
}

.upload-card.collapsed .upload-area.compact {
    display: flex;
}

/* 更换图片按钮样式 */
.btn.secondary {
    background: white;
    color: var(--primary-color);
    border: 1px solid var(--primary-color);
    padding: 8px 16px;
    font-size: 0.9rem;
}

.btn.secondary:hover {
    background: var(--primary-color);
    color: white;
}

/* 修改折叠后的控制区域样式 */
.control-area.compact {
    display: none;
    padding: 12px 16px;
    background: var(--background);
    border: none;
    border-radius: var(--border-radius);
}

.upload-card.collapsed .control-area.compact {
    display: block;
}

/* 控制组样式 */
.control-group {
    display: flex;
    align-items: center;
    gap: 16px;
    justify-content: center;
}

/* 质量控制样式优化 */
.quality-control {
    display: flex;
    align-items: center;
    gap: 8px;
    min-width: 200px;
    padding: 0 8px;
}

.quality-slider {
    flex: 1;
    height: 6px;
    background: #eee;
    border-radius: 3px;
    outline: none;
    -webkit-appearance: none;
    margin: 0;
}

.quality-slider::-webkit-slider-thumb {
    -webkit-appearance: none;
    width: 18px;
    height: 18px;
    background: white;
    border: 2px solid var(--primary-color);
    border-radius: 50%;
    cursor: pointer;
    box-shadow: 0 1px 3px rgba(0,0,0,0.2);
    transition: var(--transition);
}

.quality-slider::-webkit-slider-thumb:hover {
    transform: scale(1.1);
    box-shadow: 0 2px 5px rgba(0,0,0,0.3);
}

.quality-value {
    font-size: 0.9rem;
    color: var(--text-secondary);
    min-width: 48px;
    text-align: right;
}

/* 按钮样式优化 */
.control-group .btn {
    padding: 8px 16px;
    font-size: 0.9rem;
    white-space: nowrap;
}

/* 响应式布局 */
@media (max-width: 768px) {
    .control-group {
        flex-direction: column;
        gap: 12px;
    }
    
    .quality-control {
        width: 100%;
    }
}

/* 上传卡片折叠状态样式 */
.upload-card .upload-area.full {
    height: 200px;
    transition: var(--transition);
}

.upload-card.collapsed .upload-area.full {
    display: none;
}

.upload-card .control-area {
    display: none;
    transition: var(--transition);
}

.upload-card.collapsed .control-area {
    display: block;
}

/* 优化折叠动画 */
.upload-card {
    transition: all 0.3s ease;
}

.upload-card.collapsed {
    max-height: 80px; /* 控制折叠后的高度 */
    overflow: hidden;
}

/* 下载按钮包装器和按钮样式 */
.download-btn-wrapper {
    margin-top: 16px;
    height: 0;
    overflow: hidden;
    transition: height 0.3s ease;
}

.download-btn-wrapper.active {
    height: 44px;
    padding: 2px 0;
}

.download-btn {
    visibility: hidden;
    opacity: 0;
    transform: translateY(10px);
    transition: all 0.3s ease;
    width: 100%;
    height: 40px;
}

.download-btn.active {
    visibility: visible;
    opacity: 1;
    transform: translateY(0);
}