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

:root {
    --primary-color: #6366f1;
    --secondary-color: #8b5cf6;
    --accent-color: #ec4899;
    --success-color: #10b981;
    --dark-color: #1f2937;
    --light-color: #f9fafb;
    --gray-color: #6b7280;
    --border-radius: 12px;
    --box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    --transition: all 0.3s ease;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    padding: 20px;
    color: var(--dark-color);
}

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

header {
    text-align: center;
    padding: 40px 20px;
    color: white;
}

header h1 {
    font-size: 2.5rem;
    margin-bottom: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
}

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

.converter-section {
    background: white;
    border-radius: var(--border-radius);
    padding: 40px;
    box-shadow: var(--box-shadow);
    margin-bottom: 30px;
}

.upload-area {
    border: 3px dashed var(--primary-color);
    border-radius: var(--border-radius);
    padding: 60px 40px;
    text-align: center;
    cursor: pointer;
    transition: var(--transition);
    background: rgba(99, 102, 241, 0.05);
}

.upload-area:hover {
    background: rgba(99, 102, 241, 0.1);
    transform: translateY(-5px);
}

.upload-area.drag-over {
    background: rgba(99, 102, 241, 0.2);
    border-color: var(--secondary-color);
}

.upload-icon {
    font-size: 4rem;
    color: var(--primary-color);
    margin-bottom: 20px;
}

.upload-area h2 {
    font-size: 1.8rem;
    margin-bottom: 10px;
    color: var(--dark-color);
}

.upload-area p {
    color: var(--gray-color);
    margin-bottom: 20px;
}

.browse-btn {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    border: none;
    padding: 12px 30px;
    font-size: 1rem;
    border-radius: 50px;
    cursor: pointer;
    transition: var(--transition);
    display: inline-flex;
    align-items: center;
    gap: 10px;
    margin-top: 10px;
}

.browse-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 12px rgba(99, 102, 241, 0.3);
}

.supported-formats {
    margin-top: 20px;
    color: var(--gray-color);
    font-size: 0.9rem;
}

.preview-section, .download-section {
    margin-top: 30px;
}

.preview-header, .download-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
    padding-bottom: 15px;
    border-bottom: 2px solid var(--gray-color);
}

.preview-header h2, .download-header h2 {
    font-size: 1.5rem;
    color: var(--dark-color);
}

.clear-btn, .download-all-btn {
    background: var(--accent-color);
    color: white;
    border: none;
    padding: 10px 20px;
    border-radius: 8px;
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    align-items: center;
    gap: 8px;
}

.clear-btn:hover {
    background: #db2777;
    transform: translateY(-2px);
}

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

.download-all-btn:hover {
    background: #0da271;
    transform: translateY(-2px);
}

.images-grid, .converted-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    gap: 20px;
    margin-bottom: 30px;
}

.image-card {
    background: var(--light-color);
    border-radius: var(--border-radius);
    padding: 15px;
    box-shadow: var(--box-shadow);
    transition: var(--transition);
}

.image-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 16px rgba(0, 0, 0, 0.15);
}

.image-preview {
    width: 100%;
    height: 200px;
    object-fit: cover;
    border-radius: 8px;
    margin-bottom: 10px;
    background: #e5e7eb;
}

.image-info {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 10px;
}

.image-name {
    font-weight: 600;
    font-size: 0.9rem;
    color: var(--dark-color);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    max-width: 150px;
}

.image-size {
    color: var(--gray-color);
    font-size: 0.8rem;
}

.convert-btn {
    width: 100%;
    background: linear-gradient(135deg, var(--success-color), #0da271);
    color: white;
    border: none;
    padding: 15px;
    font-size: 1.1rem;
    border-radius: 8px;
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
    margin-top: 20px;
}

.convert-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 12px rgba(16, 185, 129, 0.3);
}

.convert-options {
    background: var(--light-color);
    padding: 20px;
    border-radius: var(--border-radius);
    margin-bottom: 20px;
}

.option-group {
    display: flex;
    align-items: center;
    gap: 15px;
    margin-bottom: 15px;
}

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

.option-group label {
    font-weight: 600;
    min-width: 80px;
    color: var(--dark-color);
}

.option-group input[type="range"] {
    flex: 1;
    height: 8px;
    border-radius: 4px;
    background: #e5e7eb;
    outline: none;
    cursor: pointer;
}

.option-group input[type="range"]::-webkit-slider-thumb {
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: var(--primary-color);
    cursor: pointer;
    border: none;
}

.option-group input[type="number"] {
    width: 100px;
    padding: 8px;
    border: 2px solid #e5e7eb;
    border-radius: 6px;
    font-size: 1rem;
    transition: var(--transition);
}

.option-group input[type="number"]:focus {
    outline: none;
    border-color: var(--primary-color);
}

.option-group span {
    min-width: 50px;
    font-weight: 600;
    color: var(--primary-color);
}

.converted-image {
    position: relative;
    cursor: pointer;
    transition: var(--transition);
}

.converted-image:hover {
    opacity: 0.8;
}

.download-individual {
    position: absolute;
    bottom: 10px;
    right: 10px;
    background: white;
    color: var(--primary-color);
    border: none;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    opacity: 0;
    transition: var(--transition);
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
}

.converted-image:hover .download-individual {
    opacity: 1;
}

footer {
    text-align: center;
    color: white;
    padding: 20px;
    font-size: 0.9rem;
    opacity: 0.8;
}

@media (max-width: 768px) {
    .container {
        padding: 10px;
    }
    
    header h1 {
        font-size: 2rem;
    }
    
    .converter-section {
        padding: 20px;
    }
    
    .upload-area {
        padding: 40px 20px;
    }
    
    .images-grid, .converted-grid {
        grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    }
    
    .option-group {
        flex-direction: column;
        align-items: flex-start;
        gap: 10px;
    }
    
    .option-group label {
        width: 100%;
    }
    
    .option-group input[type="number"] {
        width: 100%;
    }
}