:root {
    --primary-color: #4361ee;
    --primary-dark: #3a56d4;
    --secondary-color: #f8f9fa;
    --text-color: #212529;
    --light-gray: #e9ecef;
    --medium-gray: #adb5bd;
    --dark-gray: #495057;
    --white: #ffffff;
    --shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    --border-radius: 8px;
    --transition: all 0.3s ease;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

body {
    background-color: #f5f7fa;
    color: var(--text-color);
    line-height: 1.6;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

.header {
    text-align: center;
    margin-bottom: 2rem;
}

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

.header p {
    color: var(--dark-gray);
    font-size: 1.1rem;
}

.main-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
}

.upload-area {
    width: 100%;
    max-width: 600px;
    padding: 3rem 2rem;
    border: 2px dashed var(--medium-gray);
    border-radius: var(--border-radius);
    text-align: center;
    cursor: pointer;
    transition: var(--transition);
    background-color: var(--white);
    margin-bottom: 2rem;
}

.upload-area:hover {
    border-color: var(--primary-color);
    background-color: rgba(67, 97, 238, 0.05);
}

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

.upload-area h3 {
    margin-bottom: 0.5rem;
    color: var(--text-color);
}

.upload-area p {
    margin: 0.5rem 0;
    color: var(--dark-gray);
}

.file-requirements {
    margin-top: 1rem;
    font-size: 0.9rem;
    color: var(--medium-gray);
}

.btn-primary {
    background-color: var(--primary-color);
    color: var(--white);
    border: none;
    padding: 0.75rem 1.5rem;
    border-radius: var(--border-radius);
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
}

.btn-primary:hover {
    background-color: var(--primary-dark);
    box-shadow: var(--shadow);
}

.btn-primary:disabled {
    background-color: var(--medium-gray);
    cursor: not-allowed;
}

.btn-secondary {
    background-color: var(--secondary-color);
    color: var(--text-color);
    border: 1px solid var(--light-gray);
    padding: 0.75rem 1.5rem;
    border-radius: var(--border-radius);
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
}

.btn-secondary:hover {
    background-color: var(--light-gray);
    box-shadow: var(--shadow);
}

.preview-container {
    width: 100%;
    max-width: 800px;
    background-color: var(--white);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    padding: 1.5rem;
    margin-bottom: 2rem;
}

.preview-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
    padding-bottom: 1rem;
    border-bottom: 1px solid var(--light-gray);
    flex-wrap: wrap;
    gap: 1rem;
}

.options {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
}

.option-group {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.option-group label {
    font-size: 0.9rem;
    color: var(--dark-gray);
}

.option-group select, .option-group input {
    padding: 0.5rem;
    border: 1px solid var(--light-gray);
    border-radius: var(--border-radius);
    font-size: 0.9rem;
}

.option-group input[type="text"] {
    width: 200px;
}

.preview-content {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.image-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(150px, 1fr));
    gap: 1rem;
    max-height: 500px;
    overflow-y: auto;
    padding: 0.5rem;
}

.image-item {
    position: relative;
    border: 1px solid var(--light-gray);
    border-radius: var(--border-radius);
    overflow: hidden;
    aspect-ratio: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    background-color: #f8f9fa;
}

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

.image-item .remove-btn {
    position: absolute;
    top: 0.25rem;
    right: 0.25rem;
    background-color: rgba(0, 0, 0, 0.5);
    color: white;
    border: none;
    border-radius: 50%;
    width: 24px;
    height: 24px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    opacity: 0;
    transition: var(--transition);
}

.image-item:hover .remove-btn {
    opacity: 1;
}

.action-buttons {
    display: flex;
    justify-content: space-between;
    margin-top: 1.5rem;
    padding-top: 1.5rem;
    border-top: 1px solid var(--light-gray);
}

.footer {
    text-align: center;
    padding: 1rem;
    color: var(--dark-gray);
    font-size: 0.9rem;
}

.hidden {
    display: none;
}

/* Loading spinner */
.spinner {
    border: 4px solid rgba(0, 0, 0, 0.1);
    border-radius: 50%;
    border-top: 4px solid var(--primary-color);
    width: 40px;
    height: 40px;
    animation: spin 1s linear infinite;
    margin: 2rem auto;
}

.spinner.small {
    width: 20px;
    height: 20px;
    border-width: 2px;
    margin: 0;
    display: inline-block;
    vertical-align: middle;
}

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

/* Responsive adjustments */
@media (max-width: 768px) {
    .container {
        padding: 1rem;
    }
    
    .header h1 {
        font-size: 2rem;
    }
    
    .preview-header, .options {
        flex-direction: column;
        align-items: flex-start;
    }
    
    .action-buttons {
        flex-direction: column;
        gap: 1rem;
    }
    
    .btn-primary, .btn-secondary {
        width: 100%;
    }
    
    .image-grid {
        grid-template-columns: repeat(auto-fill, minmax(120px, 1fr));
    }
    
    .option-group input[type="text"] {
        width: 100%;
    }
}