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

:root {
    --primary-color: #2563eb;
    --primary-hover: #1d4ed8;
    --success-color: #10b981;
    --text-primary: #1f2937;
    --text-secondary: #6b7280;
    --border-color: #e5e7eb;
    --bg-primary: #ffffff;
    --bg-secondary: #f9fafb;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
}

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;
    padding: 2rem 1rem;
    color: var(--text-primary);
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    background: var(--bg-primary);
    border-radius: 1rem;
    box-shadow: var(--shadow-lg);
    overflow: hidden;
}

/* Header */
header {
    text-align: center;
    padding: 3rem 2rem 2rem;
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border-color);
}

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

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

/* Main Content */
main {
    padding: 2rem;
}

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

.drop-zone {
    border: 3px dashed var(--border-color);
    border-radius: 0.75rem;
    padding: 4rem 2rem;
    text-align: center;
    transition: all 0.3s ease;
    background: var(--bg-secondary);
    cursor: pointer;
}

.drop-zone:hover {
    border-color: var(--primary-color);
    background: #eff6ff;
}

.drop-zone.drag-over {
    border-color: var(--primary-color);
    background: #eff6ff;
    transform: scale(1.02);
}

.upload-icon {
    width: 4rem;
    height: 4rem;
    color: var(--text-secondary);
    margin-bottom: 1rem;
}

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

.drop-subtext {
    font-size: 1rem;
    color: var(--text-secondary);
    margin-bottom: 1.5rem;
}

.browse-btn {
    background: var(--primary-color);
    color: white;
    border: none;
    padding: 0.875rem 2rem;
    border-radius: 0.5rem;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s ease;
    box-shadow: var(--shadow-md);
}

.browse-btn:hover {
    background: var(--primary-hover);
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.browse-btn:active {
    transform: translateY(0);
}

.file-info {
    margin-top: 1.5rem;
    font-size: 0.875rem;
    color: var(--text-secondary);
}

/* Status Section */
.status-section {
    margin-bottom: 2rem;
}

.status-bar {
    background: var(--bg-secondary);
    border-radius: 0.75rem;
    padding: 1.5rem;
    border: 1px solid var(--border-color);
}

.status-text {
    font-size: 1rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 1rem;
    text-align: center;
}

.progress-bar {
    width: 100%;
    height: 0.5rem;
    background: var(--border-color);
    border-radius: 0.25rem;
    overflow: hidden;
}

.progress-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--primary-color), var(--success-color));
    border-radius: 0.25rem;
    transition: width 0.3s ease;
    width: 0%;
}

/* Results Section */
.results-section {
    margin-bottom: 2rem;
}

.results-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
    flex-wrap: wrap;
    gap: 1rem;
}

.results-header h2 {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-primary);
}

.download-all-btn {
    background: var(--success-color);
    color: white;
    border: none;
    padding: 0.75rem 1.5rem;
    border-radius: 0.5rem;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s ease;
    box-shadow: var(--shadow-md);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.download-all-btn:hover {
    background: #059669;
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

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

/* Results Grid */
.results-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    gap: 1.5rem;
    margin-bottom: 2rem;
}

.result-item {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 0.75rem;
    padding: 1rem;
    transition: all 0.2s ease;
}

.result-item:hover {
    box-shadow: var(--shadow-md);
    transform: translateY(-2px);
}

.image-comparison {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 0.5rem;
    margin-bottom: 1rem;
}

.image-box {
    position: relative;
    background: white;
    border: 1px solid var(--border-color);
    border-radius: 0.5rem;
    overflow: hidden;
    aspect-ratio: 1;
    display: flex;
    align-items: center;
    justify-content: center;
}

.image-box img {
    max-width: 100%;
    max-height: 100%;
    object-fit: contain;
}

.image-label {
    position: absolute;
    top: 0.25rem;
    left: 0.25rem;
    background: rgba(0, 0, 0, 0.7);
    color: white;
    font-size: 0.625rem;
    padding: 0.25rem 0.5rem;
    border-radius: 0.25rem;
    font-weight: 600;
}

.image-name {
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 0.75rem;
    word-break: break-word;
}

/* Format Controls */
.format-controls {
    background: white;
    border: 1px solid var(--border-color);
    border-radius: 0.5rem;
    padding: 0.75rem;
    margin-bottom: 0.75rem;
}

.control-group {
    margin-bottom: 0.75rem;
}

.control-group:last-child {
    margin-bottom: 0;
}

.control-label {
    display: block;
    font-size: 0.75rem;
    font-weight: 600;
    color: var(--text-secondary);
    margin-bottom: 0.375rem;
    text-transform: uppercase;
    letter-spacing: 0.025em;
}

.format-select {
    width: 100%;
    padding: 0.5rem;
    border: 1px solid var(--border-color);
    border-radius: 0.375rem;
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--text-primary);
    background: white;
    cursor: pointer;
    transition: border-color 0.2s ease;
}

.format-select:hover,
.format-select:focus {
    border-color: var(--primary-color);
    outline: none;
}

.quality-slider {
    width: 100%;
    height: 0.375rem;
    border-radius: 0.25rem;
    background: var(--border-color);
    outline: none;
    -webkit-appearance: none;
    appearance: none;
}

.quality-slider::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 1rem;
    height: 1rem;
    border-radius: 50%;
    background: var(--primary-color);
    cursor: pointer;
    transition: all 0.2s ease;
}

.quality-slider::-webkit-slider-thumb:hover {
    background: var(--primary-hover);
    transform: scale(1.1);
}

.quality-slider::-moz-range-thumb {
    width: 1rem;
    height: 1rem;
    border-radius: 50%;
    background: var(--primary-color);
    cursor: pointer;
    border: none;
    transition: all 0.2s ease;
}

.quality-slider::-moz-range-thumb:hover {
    background: var(--primary-hover);
    transform: scale(1.1);
}

.quality-control.hidden {
    display: none;
}

.quality-value {
    font-weight: 700;
    color: var(--primary-color);
}

.download-btn {
    width: 100%;
    background: var(--primary-color);
    color: white;
    border: none;
    padding: 0.625rem;
    border-radius: 0.5rem;
    font-size: 0.875rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s ease;
}

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

/* Reset Button */
.reset-btn {
    width: 100%;
    background: var(--bg-secondary);
    color: var(--text-primary);
    border: 2px solid var(--border-color);
    padding: 0.875rem 2rem;
    border-radius: 0.5rem;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s ease;
}

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

/* Footer */
footer {
    text-align: center;
    padding: 1.5rem;
    background: var(--bg-secondary);
    border-top: 1px solid var(--border-color);
    color: var(--text-secondary);
    font-size: 0.875rem;
}

/* Responsive Design */
@media (max-width: 768px) {
    h1 {
        font-size: 2rem;
    }

    .subtitle {
        font-size: 1rem;
    }

    .drop-zone {
        padding: 3rem 1rem;
    }

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

    .results-header {
        flex-direction: column;
        align-items: stretch;
    }

    .download-all-btn {
        justify-content: center;
    }
}

/* Animations */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(1rem);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.result-item {
    animation: fadeIn 0.3s ease forwards;
}