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

:root {
    --primary-color: #007AFF;
    --primary-hover: #0051D5;
    --secondary-color: #5856D6;
    --background: #FFFFFF;
    --surface: #FFFFFF;
    --surface-elevated: #FFFFFF;
    --text-primary: #1C1C1E;
    --text-secondary: #8E8E93;
    --text-tertiary: #C7C7CC;
    --border-color: #E5E5EA;
    --border-color-light: #F2F2F2;
    --success: #34C759;
    --warning: #FF9500;
    --error: #FF3B30;
    --shadow-sm: 0 2px 10px rgba(0, 0, 0, 0.04);
    --shadow-md: 0 4px 20px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 8px 30px rgba(0, 0, 0, 0.08);
    --radius: 14px;
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background: var(--background);
    color: var(--text-primary);
    line-height: 1.5;
    min-height: 100vh;
    position: relative;
    overflow-x: hidden;
}

/* 动态光晕背景效果 */
body::before {
    content: '';
    position: fixed;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(circle at 20% 30%, rgba(0, 122, 255, 0.05) 0%, transparent 50%),
                radial-gradient(circle at 80% 70%, rgba(88, 86, 214, 0.05) 0%, transparent 50%),
                radial-gradient(circle at 40% 80%, rgba(52, 199, 89, 0.03) 0%, transparent 50%);
    animation: floatingGlow 20s ease-in-out infinite;
    z-index: -1;
}

@keyframes floatingGlow {
    0%, 100% {
        transform: translate(0, 0) rotate(0deg);
    }
    33% {
        transform: translate(20px, -20px) rotate(1deg);
    }
    66% {
        transform: translate(-20px, 10px) rotate(-1deg);
    }
}

.container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 2rem;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

.header {
    text-align: center;
    margin-bottom: 3rem;
}

.title {
    font-size: 2.75rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    margin-bottom: 0.75rem;
    letter-spacing: -0.02em;
}

.subtitle {
    color: var(--text-secondary);
    font-size: 1.125rem;
    font-weight: 400;
}

.main {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 2rem;
}

.upload-section {
    width: 100%;
}

.upload-area {
    background: var(--surface-elevated);
    border: 2px dashed var(--border-color);
    border-radius: var(--radius);
    padding: 3rem;
    text-align: center;
    cursor: pointer;
    transition: var(--transition);
    position: relative;
    overflow: hidden;
    box-shadow: var(--shadow-sm);
}

.upload-area:hover {
    border-color: var(--primary-color);
    background: rgba(0, 122, 255, 0.02);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.upload-area.dragover {
    border-color: var(--primary-color);
    background: rgba(0, 122, 255, 0.05);
    transform: scale(1.01);
    box-shadow: var(--shadow-lg);
}

.upload-icon {
    color: var(--text-secondary);
    margin-bottom: 1.5rem;
}

.upload-text {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
}

.upload-hint {
    color: var(--text-secondary);
    font-size: 0.9375rem;
}

.options-section {
    background: var(--surface-elevated);
    border-radius: var(--radius);
    padding: 2rem;
    box-shadow: var(--shadow-sm);
}

.label {
    display: block;
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--text-primary);
    font-size: 0.9375rem;
}

.format-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(100px, 1fr));
    gap: 0.75rem;
}

.format-btn {
    padding: 0.75rem 1rem;
    border: 2px solid var(--border-color);
    background: var(--surface);
    border-radius: 10px;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
    color: var(--text-primary);
    font-size: 0.875rem;
}

.format-btn:hover {
    border-color: var(--primary-color);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

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

.quality-control {
    margin-top: 2rem;
}

.quality-slider {
    display: flex;
    align-items: center;
    gap: 1rem;
}

#qualitySlider {
    flex: 1;
    height: 6px;
    border-radius: 3px;
    background: var(--border-color);
    outline: none;
    -webkit-appearance: none;
}

#qualitySlider::-webkit-slider-thumb {
    -webkit-appearance: none;
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: var(--primary-color);
    cursor: pointer;
    box-shadow: var(--shadow-md);
    transition: var(--transition);
}

#qualitySlider::-webkit-slider-thumb:hover {
    transform: scale(1.2);
}

.quality-value {
    min-width: 50px;
    text-align: center;
    font-weight: 600;
    color: var(--primary-color);
    font-size: 0.9375rem;
}

.resize-control {
    margin-top: 2rem;
}

.resize-control label {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    cursor: pointer;
    font-size: 0.9375rem;
}

.resize-control input[type="checkbox"] {
    width: 20px;
    height: 20px;
    cursor: pointer;
}

.resize-inputs {
    margin-top: 1rem;
}

.preset-sizes {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin-bottom: 1rem;
}

.preset-btn {
    padding: 0.5rem 1rem;
    background: var(--background);
    border: 2px solid var(--border-color);
    border-radius: 8px;
    cursor: pointer;
    transition: var(--transition);
    font-size: 0.875rem;
    font-weight: 500;
}

.preset-btn:hover {
    border-color: var(--primary-color);
    background: rgba(0, 122, 255, 0.05);
}

.input-group {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    margin-bottom: 1rem;
}

.input-group input {
    width: 120px;
    padding: 0.625rem;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    font-size: 0.9375rem;
    transition: var(--transition);
}

.input-group input:focus {
    outline: none;
    border-color: var(--primary-color);
}

.separator {
    color: var(--text-secondary);
    font-weight: 600;
}

.resize-options {
    display: flex;
    gap: 0.5rem;
}

.aspect-ratio-btn, .resize-mode-btn {
    padding: 0.5rem 1rem;
    background: var(--background);
    border: 2px solid var(--border-color);
    border-radius: 8px;
    cursor: pointer;
    transition: var(--transition);
    font-weight: 500;
    font-size: 0.875rem;
}

.aspect-ratio-btn:hover, .resize-mode-btn:hover {
    border-color: var(--primary-color);
}

.aspect-ratio-btn.active, .resize-mode-btn.active {
    background: var(--primary-color);
    border-color: var(--primary-color);
    color: white;
}

.advanced-options {
    margin-top: 2rem;
    display: flex;
    gap: 2rem;
}

.advanced-options label {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    cursor: pointer;
    font-size: 0.9375rem;
}

.preview-section {
    background: var(--surface-elevated);
    border-radius: var(--radius);
    padding: 2rem;
    box-shadow: var(--shadow-sm);
}

.preview-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
}

.section-title {
    font-size: 1.375rem;
    font-weight: 600;
}

.preview-controls {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.view-toggle-btn {
    padding: 0.5rem;
    background: var(--background);
    border: 2px solid var(--border-color);
    border-radius: 8px;
    cursor: pointer;
    transition: var(--transition);
}

.view-toggle-btn:hover {
    border-color: var(--primary-color);
}

.view-toggle-btn.active {
    background: var(--primary-color);
    border-color: var(--primary-color);
    color: white;
}

.clear-all-btn {
    padding: 0.5rem 1rem;
    background: var(--error);
    color: white;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    transition: var(--transition);
    font-weight: 500;
    font-size: 0.875rem;
}

.clear-all-btn:hover {
    background: #E6342A;
}

.preview-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: 1.5rem;
}

.preview-grid.list-view {
    grid-template-columns: 1fr;
}

.preview-item {
    position: relative;
    border-radius: 12px;
    overflow: hidden;
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
    background: var(--surface);
    border: 1px solid var(--border-color-light);
}

.preview-item:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.preview-item.list-view {
    display: flex;
    align-items: center;
    padding: 1rem;
    gap: 1rem;
}

.preview-item img {
    width: 100%;
    height: 150px;
    object-fit: cover;
    display: block;
    cursor: pointer;
}

.preview-item.list-view img {
    width: 80px;
    height: 80px;
    border-radius: 8px;
}

.preview-info {
    padding: 0.875rem;
    background: var(--surface);
    border-top: 1px solid var(--border-color-light);
}

.preview-item.list-view .preview-info {
    border-top: none;
    flex: 1;
}

.preview-name {
    font-weight: 500;
    font-size: 0.9375rem;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.preview-size {
    color: var(--text-secondary);
    font-size: 0.8125rem;
    margin-top: 0.25rem;
}

.preview-dimensions {
    color: var(--text-secondary);
    font-size: 0.8125rem;
    margin-top: 0.25rem;
}

.preview-actions {
    position: absolute;
    top: 0.5rem;
    right: 0.5rem;
    display: flex;
    gap: 0.5rem;
    opacity: 0;
    transition: var(--transition);
}

.preview-item:hover .preview-actions {
    opacity: 1;
}

.preview-action-btn {
    width: 32px;
    height: 32px;
    background: rgba(0, 0, 0, 0.7);
    color: white;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition);
}

.preview-action-btn:hover {
    background: rgba(0, 0, 0, 0.9);
    transform: scale(1.1);
}

.progress-section {
    background: var(--surface-elevated);
    border-radius: var(--radius);
    padding: 1.5rem;
    box-shadow: var(--shadow-sm);
}

.progress-bar {
    width: 100%;
    height: 8px;
    background: var(--border-color);
    border-radius: 4px;
    overflow: hidden;
    margin-bottom: 1rem;
}

.progress-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--primary-color), var(--secondary-color));
    border-radius: 4px;
    transition: width 0.3s ease;
    width: 0%;
}

.progress-text {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

#progressText {
    color: var(--text-primary);
    font-weight: 500;
    font-size: 0.9375rem;
}

#progressPercent {
    color: var(--primary-color);
    font-weight: 600;
    font-size: 0.9375rem;
}

.action-section {
    display: flex;
    gap: 1rem;
    justify-content: center;
    flex-wrap: wrap;
}

.convert-btn, .download-all-btn, .download-zip-btn {
    padding: 1rem 2rem;
    background: var(--primary-color);
    color: white;
    border: none;
    border-radius: var(--radius);
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    align-items: center;
    gap: 0.5rem;
    box-shadow: var(--shadow-md);
}

.convert-btn:hover, .download-all-btn:hover, .download-zip-btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.convert-btn:active, .download-all-btn:active, .download-zip-btn:active {
    transform: translateY(0);
}

.download-all-btn {
    background: var(--success);
}

.download-all-btn:hover {
    background: #2FA848;
}

.download-zip-btn {
    background: var(--secondary-color);
}

.download-zip-btn:hover {
    background: #4640B8;
}

.footer {
    text-align: center;
    padding: 2rem 0;
    border-top: 1px solid var(--border-color-light);
    margin-top: 3rem;
}

.footer p {
    color: var(--text-secondary);
    margin-bottom: 0.5rem;
    font-size: 0.9375rem;
}

.license-link {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 500;
    transition: var(--transition);
    font-size: 0.9375rem;
}

.license-link:hover {
    text-decoration: underline;
}

.modal {
    position: fixed;
    z-index: 1000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.8);
    display: flex;
    align-items: center;
    justify-content: center;
    animation: fadeIn 0.3s ease;
}

.modal-content {
    position: relative;
    max-width: 90%;
    max-height: 90%;
    background: var(--surface);
    border-radius: var(--radius);
    overflow: hidden;
    box-shadow: var(--shadow-lg);
}

.modal-close {
    position: absolute;
    top: 1rem;
    right: 1rem;
    color: white;
    font-size: 2rem;
    font-weight: bold;
    cursor: pointer;
    z-index: 1001;
    background: rgba(0, 0, 0, 0.5);
    width: 40px;
    height: 40px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition);
}

.modal-close:hover {
    background: rgba(0, 0, 0, 0.8);
}

#modalImage {
    max-width: 100%;
    max-height: 70vh;
    object-fit: contain;
}

.modal-info {
    padding: 1.5rem;
    background: var(--surface);
}

.modal-info h3 {
    margin-bottom: 0.5rem;
    color: var(--text-primary);
    font-size: 1.125rem;
}

.modal-info p {
    color: var(--text-secondary);
    font-size: 0.9375rem;
}

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

@media (max-width: 768px) {
    .container {
        padding: 1rem;
    }
    
    .title {
        font-size: 2.25rem;
    }
    
    .subtitle {
        font-size: 1rem;
    }
    
    .format-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .preview-grid {
        grid-template-columns: repeat(auto-fill, minmax(150px, 1fr));
    }
    
    .action-section {
        flex-direction: column;
    }
    
    .convert-btn, .download-all-btn, .download-zip-btn {
        width: 100%;
        justify-content: center;
    }
    
    .advanced-options {
        flex-direction: column;
        gap: 1rem;
    }
    
    .preview-header {
        flex-direction: column;
        gap: 1rem;
        align-items: flex-start;
    }
}