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

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

.container {
    max-width: 900px;
    margin: 0 auto;
    background: white;
    border-radius: 20px;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
    overflow: hidden;
}

header {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 40px;
    text-align: center;
}

header h1 {
    font-size: 2.5rem;
    margin-bottom: 10px;
}

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

.upload-section {
    padding: 40px;
}

.file-types {
    display: flex;
    gap: 20px;
    margin-bottom: 30px;
    justify-content: center;
}

.file-type-option {
    flex: 1;
    max-width: 200px;
}

.file-type-option input[type="radio"] {
    display: none;
}

.file-type-option label {
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 20px;
    border: 3px solid #e0e0e0;
    border-radius: 15px;
    cursor: pointer;
    transition: all 0.3s ease;
    background: #f8f9fa;
}

.file-type-option input[type="radio"]:checked + label {
    border-color: #667eea;
    background: #f0f4ff;
}

.file-type-option .icon {
    font-size: 3rem;
    margin-bottom: 10px;
}

.file-type-option span:last-child {
    font-weight: 600;
    color: #333;
}

.dropzone {
    border: 3px dashed #ccc;
    border-radius: 15px;
    padding: 60px 20px;
    text-align: center;
    cursor: pointer;
    transition: all 0.3s ease;
    background: #fafafa;
    margin-bottom: 30px;
}

.dropzone:hover,
.dropzone.drag-over {
    border-color: #667eea;
    background: #f0f4ff;
}

.dropzone-content {
    pointer-events: none;
}

.upload-icon {
    font-size: 4rem;
    display: block;
    margin-bottom: 20px;
}

.dropzone-text {
    font-size: 1.3rem;
    color: #333;
    margin-bottom: 10px;
    font-weight: 500;
}

.dropzone-hint {
    color: #666;
    font-size: 0.9rem;
}

.dropzone-hint-alt {
    color: #667eea;
    font-size: 0.95rem;
    font-weight: 600;
    margin-top: 15px;
    padding: 10px;
    background: #f0f4ff;
    border-radius: 5px;
}

.config-section {
    background: #f8f9fa;
    padding: 25px;
    border-radius: 15px;
    margin-bottom: 30px;
}

.config-section h3 {
    margin-bottom: 20px;
    color: #333;
}

.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    margin-bottom: 8px;
    font-weight: 600;
    color: #555;
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 12px;
    border: 2px solid #e0e0e0;
    border-radius: 8px;
    font-size: 1rem;
    transition: border-color 0.3s ease;
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: #667eea;
}

.convert-btn {
    width: 100%;
    padding: 18px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border: none;
    border-radius: 12px;
    font-size: 1.2rem;
    font-weight: 600;
    cursor: pointer;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.convert-btn:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: 0 10px 25px rgba(102, 126, 234, 0.4);
}

.convert-btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.files-list {
    padding: 0 40px 20px;
}

.files-list h3 {
    margin-bottom: 15px;
    color: #333;
}

#filesContainer {
    background: #f8f9fa;
    padding: 15px;
    border-radius: 10px;
}

.file-item {
    display: flex;
    align-items: center;
    padding: 10px;
    background: white;
    border-radius: 8px;
    margin-bottom: 8px;
}

.file-item:last-child {
    margin-bottom: 0;
}

.file-item span {
    margin-right: 10px;
}

.progress-section {
    padding: 20px 40px;
}

.progress-bar {
    width: 100%;
    height: 30px;
    background: #e0e0e0;
    border-radius: 15px;
    overflow: hidden;
    margin-bottom: 10px;
}

.progress-fill {
    height: 100%;
    background: linear-gradient(90deg, #667eea 0%, #764ba2 100%);
    transition: width 0.3s ease;
    width: 0%;
}

.progress-text {
    text-align: center;
    color: #666;
    font-weight: 500;
}

.result-section {
    padding: 40px;
}

.success-message {
    text-align: center;
}

.success-icon {
    font-size: 5rem;
    display: block;
    margin-bottom: 20px;
}

.success-message h3 {
    font-size: 2rem;
    color: #333;
    margin-bottom: 10px;
}

.success-message p {
    color: #666;
    margin-bottom: 30px;
    font-size: 1.1rem;
}

.download-btn {
    padding: 18px 40px;
    background: #28a745;
    color: white;
    border: none;
    border-radius: 12px;
    font-size: 1.2rem;
    font-weight: 600;
    cursor: pointer;
    margin-bottom: 15px;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.download-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 25px rgba(40, 167, 69, 0.4);
}

.reset-btn {
    padding: 12px 30px;
    background: #6c757d;
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    cursor: pointer;
    transition: background 0.3s ease;
}

.reset-btn:hover {
    background: #5a6268;
}

@media (max-width: 768px) {
    header h1 {
        font-size: 2rem;
    }

    .file-types {
        flex-direction: column;
    }

    .file-type-option {
        max-width: 100%;
    }

    .upload-section {
        padding: 20px;
    }
}