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

:root {
    --primary-color: #007bff;
    --secondary-color: #6c757d;
    --success-color: #28a745;
    --danger-color: #dc3545;
    --background: #f8f9fa;
    --surface: #ffffff;
    --text-primary: #212529;
    --text-secondary: #6c757d;
    --border-color: #dee2e6;
    --border-radius: 8px;
    --box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
    --transition: all 0.3s ease;
}

html {
    scroll-behavior: smooth;
}

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;
    color: var(--text-primary);
    line-height: 1.6;
}

.container {
    max-width: 900px;
    margin: 0 auto;
    padding: 20px;
}

.header {
    text-align: center;
    color: white;
    margin-bottom: 40px;
    padding: 20px 0;
}

.header h1 {
    font-size: 2.5rem;
    margin-bottom: 10px;
    font-weight: 700;
}

.header p {
    font-size: 1.1rem;
    opacity: 0.9;
}

.main-content {
    animation: slideUp 0.5s ease;
}

@keyframes slideUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.section {
    background: var(--surface);
    border-radius: var(--border-radius);
    padding: 30px;
    margin-bottom: 20px;
    box-shadow: var(--box-shadow);
}

.section h2 {
    font-size: 1.5rem;
    margin-bottom: 20px;
    color: var(--text-primary);
    border-bottom: 2px solid var(--primary-color);
    padding-bottom: 10px;
}

/* Upload Section */
.upload-area {
    border: 3px dashed var(--border-color);
    border-radius: var(--border-radius);
    padding: 60px 20px;
    text-align: center;
    cursor: pointer;
    transition: var(--transition);
    background: #f8f9fa;
}

.upload-area:hover {
    border-color: var(--primary-color);
    background: #e7f3ff;
}

.upload-area.dragover {
    border-color: var(--primary-color);
    background: #e7f3ff;
    transform: scale(1.02);
}

.upload-icon {
    width: 60px;
    height: 60px;
    color: var(--primary-color);
    margin-bottom: 15px;
}

.upload-area h3 {
    font-size: 1.2rem;
    margin-bottom: 5px;
}

.upload-area p {
    color: var(--text-secondary);
}

/* Preview Section */
.preview-section {
    display: none;
}

.preview-container {
    background: #f8f9fa;
    border-radius: var(--border-radius);
    padding: 20px;
    text-align: center;
}

.preview-container img {
    max-width: 100%;
    max-height: 300px;
    border-radius: 6px;
    margin-bottom: 15px;
    box-shadow: 0 2px 6px rgba(0, 0, 0, 0.1);
}

.image-info {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 15px;
    text-align: left;
}

.image-info p {
    background: white;
    padding: 12px;
    border-radius: 6px;
    border-left: 4px solid var(--primary-color);
}

/* Settings Section */
.settings-section {
    display: none;
}

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

.settings-group label {
    display: block;
    margin-bottom: 8px;
    font-weight: 500;
    color: var(--text-primary);
}

.settings-group input[type="number"],
.settings-group select {
    width: 100%;
    padding: 10px 12px;
    border: 1px solid var(--border-color);
    border-radius: 6px;
    font-size: 1rem;
    transition: var(--transition);
}

.settings-group input[type="number"]:focus,
.settings-group select:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(0, 123, 255, 0.1);
}

.settings-group input[type="checkbox"] {
    margin-right: 8px;
    cursor: pointer;
    width: 18px;
    height: 18px;
}

.settings-group label {
    display: flex;
    align-items: center;
    cursor: pointer;
}

.setting-hint {
    font-size: 0.85rem;
    color: var(--text-secondary);
    margin-top: 5px;
    margin-left: 26px;
}

/* Slider */
.slider-container {
    display: flex;
    align-items: center;
    gap: 15px;
}

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

#qualitySlider::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: var(--primary-color);
    cursor: pointer;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
}

#qualitySlider::-moz-range-thumb {
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: var(--primary-color);
    cursor: pointer;
    border: none;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
}

#qualityValue {
    min-width: 40px;
    text-align: right;
    font-weight: 500;
    color: var(--primary-color);
}

/* Processing Section */
.processing-section {
    display: none;
    text-align: center;
}

.processing-container {
    padding: 40px 20px;
}

.spinner {
    display: inline-block;
    width: 40px;
    height: 40px;
    border: 4px solid var(--border-color);
    border-top: 4px solid var(--primary-color);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

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

.processing-container p {
    margin-top: 15px;
    font-size: 1.1rem;
    color: var(--text-secondary);
}

/* Output Preview Section */
.output-preview-section {
    display: none;
}

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

.preview-side {
    background: #f8f9fa;
    border-radius: var(--border-radius);
    padding: 15px;
    border: 2px solid var(--border-color);
}

.preview-side h3 {
    margin-bottom: 12px;
    font-size: 1.1rem;
    color: var(--text-primary);
}

.preview-side img {
    display: block;
    margin-bottom: 12px;
    max-height: 300px;
    width: 100%;
    object-fit: contain;
}

.original-side {
    border-left: 4px solid var(--secondary-color);
}

.output-side {
    border-left: 4px solid var(--primary-color);
}

.dimension-info {
    font-size: 0.85rem;
    color: var(--text-secondary);
}

.dimension-info p {
    margin: 6px 0;
    padding: 6px;
    background: white;
    border-radius: 4px;
}

.dimension-info strong {
    color: var(--text-primary);
}

.preview-stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 12px;
    background: #e7f3ff;
    border-radius: var(--border-radius);
    padding: 15px;
    margin-bottom: 15px;
}

.stat-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 8px;
    background: white;
    border-radius: 6px;
    border-left: 3px solid var(--primary-color);
}

.stat-label {
    font-weight: 500;
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.stat-value {
    font-weight: 600;
    color: var(--primary-color);
    font-size: 1rem;
}

#outputPreview {
    display: block;
    margin: 0 auto;
    border-radius: 6px;
}

.info-text {
    margin-top: 15px;
    padding: 12px;
    background: #e7f3ff;
    border-radius: 6px;
    color: var(--text-secondary);
    font-size: 0.9rem;
}

/* Actions Section */
.actions-section {
    display: none;
}

.actions-section {
    display: flex;
    gap: 12px;
    flex-wrap: wrap;
    justify-content: center;
}

/* Buttons */
.btn {
    padding: 12px 24px;
    font-size: 1rem;
    font-weight: 600;
    border: none;
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: var(--transition);
}

.btn-primary {
    background: var(--primary-color);
    color: white;
    flex: 1;
    min-width: 200px;
}

.btn-primary:hover {
    background: #0056b3;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0, 123, 255, 0.3);
}

.btn-secondary {
    background: var(--secondary-color);
    color: white;
    flex: 1;
    min-width: 200px;
}

.btn-secondary:hover {
    background: #5a6268;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(108, 117, 125, 0.3);
}

.btn-outline {
    background: transparent;
    color: var(--primary-color);
    border: 2px solid var(--primary-color);
    flex: 1;
    min-width: 200px;
}

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

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    transform: none;
}

/* Error Message */
.error-message {
    background: #f8d7da;
    color: #721c24;
    padding: 15px;
    border-radius: var(--border-radius);
    margin-top: 15px;
    border-left: 4px solid var(--danger-color);
}

.success-message {
    background: #d4edda;
    color: #155724;
    padding: 15px;
    border-radius: var(--border-radius);
    margin-top: 15px;
    border-left: 4px solid var(--success-color);
}

/* Footer */
.footer {
    text-align: center;
    color: white;
    padding: 20px;
    margin-top: 40px;
    opacity: 0.9;
}

/* Responsive */
@media (max-width: 768px) {
    .header h1 {
        font-size: 1.8rem;
    }

    .section {
        padding: 20px;
    }

    .actions-section {
        flex-direction: column;
    }

    .btn {
        width: 100%;
        min-width: unset;
    }

    .image-info {
        grid-template-columns: 1fr;
    }

    .comparison-container {
        grid-template-columns: 1fr;
        gap: 15px;
    }

    .preview-side img {
        max-height: 250px;
    }

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