:root {
    --primary-color: #4a6bff;
    --secondary-color: #f8f9fa;
    --text-color: #333;
    --light-text: #777;
    --border-color: #ddd;
    --success-color: #28a745;
    --error-color: #dc3545;
    --warning-color: #ffc107;
    --shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    --border-radius: 8px;
}

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

body {
    background-color: #f5f7ff;
    color: var(--text-color);
    line-height: 1.6;
}

.container {
    max-width: 900px;
    margin: 0 auto;
    padding: 2rem;
}

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

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

header h1 i {
    margin-right: 0.5rem;
}

header p {
    color: var(--light-text);
    font-size: 1.1rem;
}

.upload-area {
    background-color: white;
    border: 2px dashed var(--border-color);
    border-radius: var(--border-radius);
    padding: 3rem 2rem;
    text-align: center;
    cursor: pointer;
    transition: all 0.3s ease;
    margin-bottom: 2rem;
    box-shadow: var(--shadow);
}

.upload-area:hover {
    border-color: var(--primary-color);
    background-color: rgba(74, 107, 255, 0.05);
}

.upload-area i {
    font-size: 3rem;
    color: var(--primary-color);
    margin-bottom: 1rem;
}

.upload-area h3 {
    margin-bottom: 0.5rem;
    font-weight: 600;
}

.upload-area p {
    color: var(--light-text);
    margin: 1rem 0;
}

.btn {
    background-color: var(--primary-color);
    color: white;
    border: none;
    padding: 0.8rem 1.5rem;
    border-radius: var(--border-radius);
    font-size: 1rem;
    cursor: pointer;
    transition: all 0.3s ease;
    font-weight: 500;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
}

.btn:hover {
    background-color: #3a5bef;
    transform: translateY(-2px);
    box-shadow: var(--shadow);
}

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

.btn.cancel-btn {
    background-color: var(--error-color);
}

.btn.cancel-btn:hover {
    background-color: #c82333;
}

.btn.new-file-btn {
    background-color: var(--warning-color);
    color: #212529;
}

.btn.new-file-btn:hover {
    background-color: #e0a800;
}

.options {
    background-color: white;
    border-radius: var(--border-radius);
    padding: 2rem;
    margin-bottom: 2rem;
    box-shadow: var(--shadow);
}

.file-info {
    margin-bottom: 1.5rem;
    padding: 1rem;
    background-color: var(--secondary-color);
    border-radius: var(--border-radius);
    border-left: 4px solid var(--primary-color);
}

.file-info p {
    font-weight: 500;
}

.options h3 {
    margin-bottom: 1.5rem;
    font-size: 1.3rem;
    color: var(--primary-color);
}

.option-group {
    margin-bottom: 1.5rem;
}

.option-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
}

.option-group select {
    width: 100%;
    padding: 0.8rem;
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    font-size: 1rem;
    background-color: var(--secondary-color);
}

.convert-btn {
    width: 100%;
    margin-top: 1rem;
    padding: 1rem;
    font-size: 1.1rem;
}

.cancel-btn {
    width: 100%;
    margin-top: 0.5rem;
    padding: 1rem;
    font-size: 1.1rem;
}

.progress-container {
    background-color: white;
    border-radius: var(--border-radius);
    padding: 2rem;
    margin-bottom: 2rem;
    box-shadow: var(--shadow);
    text-align: center;
}

.progress-container h3 {
    margin-bottom: 1rem;
    color: var(--primary-color);
}

.progress-bar {
    width: 100%;
    height: 10px;
    background-color: var(--secondary-color);
    border-radius: 5px;
    margin-bottom: 0.5rem;
    overflow: hidden;
}

.progress {
    height: 100%;
    background-color: var(--primary-color);
    width: 0%;
    transition: width 0.3s ease;
}

.results {
    background-color: white;
    border-radius: var(--border-radius);
    padding: 2rem;
    box-shadow: var(--shadow);
}

.results h3 {
    margin-bottom: 1.5rem;
    font-size: 1.3rem;
    color: var(--primary-color);
}

.download-options {
    display: flex;
    gap: 1rem;
    margin-bottom: 2rem;
    flex-wrap: wrap;
}

.download-btn {
    flex: 1;
    min-width: 200px;
}

.preview-container {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: 1rem;
}

.preview-item {
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    overflow: hidden;
    box-shadow: var(--shadow);
}

.preview-item img {
    width: 100%;
    height: auto;
    display: block;
}

.preview-item p {
    padding: 0.5rem;
    text-align: center;
    font-size: 0.9rem;
    background-color: var(--secondary-color);
}

footer {
    text-align: center;
    margin-top: 2rem;
    color: var(--light-text);
    font-size: 0.9rem;
}

@media (max-width: 768px) {
    .container {
        padding: 1rem;
    }
    
    header h1 {
        font-size: 2rem;
    }
    
    .download-options {
        flex-direction: column;
    }
    
    .download-btn {
        width: 100%;
    }
}