:root {
    --primary-color: #3b82f6;
    --primary-hover: #2563eb;
    --secondary-color: #64748b;
    --background: #f8fafc;
    --surface: #ffffff;
    --text-primary: #0f172a;
    --text-secondary: #64748b;
    --border-color: #e2e8f0;
    --success-color: #10b981;
    --danger-color: #ef4444;
    --shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background: var(--background);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
    padding: 2rem 1rem;
}

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

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

.header h1 {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
}

.subtitle {
    font-size: 1.125rem;
    color: var(--text-secondary);
    margin-bottom: 1rem;
}

.security-badge {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem 1rem;
    background: linear-gradient(135deg, #10b981, #059669);
    color: white;
    border-radius: 50px;
    font-size: 0.875rem;
    font-weight: 500;
    box-shadow: 0 2px 8px rgba(16, 185, 129, 0.3);
}

.security-badge svg {
    flex-shrink: 0;
}

.main-content {
    background: var(--surface);
    border-radius: 12px;
    padding: 2rem;
    box-shadow: var(--shadow-lg);
    margin-bottom: 2rem;
}

/* Upload Section */
.upload-section {
    margin-bottom: 2rem;
}

.drop-zone {
    border: 2px dashed var(--border-color);
    border-radius: 12px;
    padding: 3rem 2rem;
    text-align: center;
    transition: all 0.3s;
    cursor: pointer;
    position: relative;
}

.drop-zone:hover {
    border-color: var(--primary-color);
    background: rgba(59, 130, 246, 0.02);
}

.drop-zone.drag-over {
    border-color: var(--primary-color);
    background: rgba(59, 130, 246, 0.05);
    transform: scale(1.01);
}

.upload-icon {
    color: var(--primary-color);
    margin-bottom: 1rem;
}

.drop-zone h3 {
    color: var(--text-primary);
    font-size: 1.25rem;
    margin-bottom: 0.5rem;
}

.drop-zone p {
    color: var(--text-secondary);
    margin-bottom: 1.5rem;
}

.supported-formats {
    margin-top: 1rem;
    font-size: 0.875rem;
    color: var(--text-secondary);
}

#fileInput {
    display: none;
}

button {
    padding: 0.75rem 1.5rem;
    font-size: 1rem;
    font-weight: 500;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.2s;
    font-family: inherit;
}

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

.btn-primary:hover {
    background: var(--primary-hover);
    transform: translateY(-1px);
    box-shadow: var(--shadow);
}

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

.btn-secondary {
    background: var(--background);
    color: var(--text-secondary);
    border: 1px solid var(--border-color);
}

.btn-secondary:hover {
    background: #e2e8f0;
    color: var(--text-primary);
}

.btn-danger {
    background: var(--danger-color);
    color: white;
    padding: 0.5rem 1rem;
    font-size: 0.875rem;
}

.btn-danger:hover {
    background: #dc2626;
}

.btn-success {
    background: var(--success-color);
    color: white;
    padding: 0.5rem 1rem;
    font-size: 0.875rem;
}

.btn-success:hover {
    background: #059669;
}

/* Settings Section */
.settings-section {
    display: none;
    margin-bottom: 2rem;
    padding: 1.5rem;
    background: var(--background);
    border-radius: 8px;
}

.settings-section.visible {
    display: block;
}

.settings-section h3 {
    font-size: 1.125rem;
    margin-bottom: 1.5rem;
    color: var(--text-primary);
}

.settings-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
    margin-bottom: 1.5rem;
}

.setting-item {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.setting-item label {
    font-weight: 500;
    color: var(--text-primary);
    font-size: 0.875rem;
}

.setting-item input[type="range"] {
    width: 100%;
    height: 6px;
    border-radius: 3px;
    background: var(--border-color);
    outline: none;
    -webkit-appearance: none;
}

.setting-item input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 18px;
    height: 18px;
    border-radius: 50%;
    background: var(--primary-color);
    cursor: pointer;
}

.setting-item input[type="range"]::-moz-range-thumb {
    width: 18px;
    height: 18px;
    border-radius: 50%;
    background: var(--primary-color);
    cursor: pointer;
    border: none;
}

.setting-item select,
.setting-item input[type="number"] {
    padding: 0.5rem;
    border: 1px solid var(--border-color);
    border-radius: 6px;
    font-size: 0.875rem;
    font-family: inherit;
}

.setting-item select:focus,
.setting-item input[type="number"]:focus {
    outline: none;
    border-color: var(--primary-color);
}

.setting-hint {
    font-size: 0.75rem;
    color: var(--text-secondary);
    margin: 0;
}

.actions {
    display: flex;
    gap: 0.75rem;
}

/* Images Section */
.images-section {
    display: none;
}

.images-section.visible {
    display: block;
}

.image-card {
    background: var(--background);
    border-radius: 8px;
    padding: 1.5rem;
    margin-bottom: 1.5rem;
    border: 1px solid var(--border-color);
}

.image-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
}

.image-name {
    font-weight: 600;
    color: var(--text-primary);
    word-break: break-word;
}

.image-actions {
    display: flex;
    gap: 0.5rem;
}

.comparison {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 1.5rem;
    margin-bottom: 1rem;
}

.preview-box {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.preview-label {
    font-weight: 500;
    color: var(--text-primary);
    font-size: 0.875rem;
}

.preview-container {
    background: white;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    overflow: hidden;
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 200px;
    position: relative;
}

.preview-container img {
    max-width: 100%;
    max-height: 400px;
    object-fit: contain;
}

.preview-info {
    padding: 0.75rem;
    background: white;
    border: 1px solid var(--border-color);
    border-radius: 6px;
    font-size: 0.875rem;
}

.info-row {
    display: flex;
    justify-content: space-between;
    margin-bottom: 0.5rem;
}

.info-row:last-child {
    margin-bottom: 0;
}

.info-label {
    color: var(--text-secondary);
}

.info-value {
    font-weight: 600;
    color: var(--text-primary);
    font-family: 'Monaco', 'Courier New', monospace;
}

.savings {
    padding: 1rem;
    background: linear-gradient(135deg, #10b981, #059669);
    color: white;
    border-radius: 6px;
    text-align: center;
    font-weight: 600;
}

.savings.negative {
    background: linear-gradient(135deg, #f59e0b, #d97706);
}

.processing {
    padding: 1rem;
    text-align: center;
    color: var(--text-secondary);
}

.spinner {
    display: inline-block;
    width: 20px;
    height: 20px;
    border: 3px solid var(--border-color);
    border-top-color: var(--primary-color);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
    margin-right: 0.5rem;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

.download-all-section {
    margin-top: 2rem;
    padding: 1.5rem;
    background: var(--background);
    border-radius: 8px;
    text-align: center;
}

/* Info Section */
.info-section {
    background: var(--surface);
    border-radius: 12px;
    padding: 2rem;
    box-shadow: var(--shadow);
}

.info-section h3 {
    color: var(--text-primary);
    margin-bottom: 1rem;
    font-size: 1.25rem;
}

.info-section ul {
    list-style: none;
    padding-left: 0;
}

.info-section li {
    padding-left: 1.5rem;
    margin-bottom: 0.75rem;
    position: relative;
    color: var(--text-secondary);
}

.info-section li::before {
    content: '✓';
    position: absolute;
    left: 0;
    color: var(--success-color);
    font-weight: 600;
}

/* Responsive */
@media (max-width: 768px) {
    body {
        padding: 1rem;
    }

    .header h1 {
        font-size: 2rem;
    }

    .main-content {
        padding: 1.5rem;
    }

    .drop-zone {
        padding: 2rem 1rem;
    }

    .settings-grid {
        grid-template-columns: 1fr;
    }

    .actions {
        flex-direction: column;
    }

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

    .image-header {
        flex-direction: column;
        gap: 1rem;
        align-items: flex-start;
    }
}