:root {
    --primary-color: #4361ee;
    --secondary-color: #3a0ca3;
    --accent-color: #4895ef;
    --success-color: #4cc9f0;
    --error-color: #f72585;
    --light-color: #f8f9fa;
    --dark-color: #212529;
    --border-radius: 12px;
    --box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    --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: #f5f7ff;
    color: var(--dark-color);
    line-height: 1.6;
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 20px;
}

.container {
    width: 100%;
    max-width: 800px;
}

.converter-card {
    background-color: white;
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
    padding: 40px;
    transition: var(--transition);
}

.header {
    text-align: center;
    margin-bottom: 30px;
}

.header h1 {
    color: var(--primary-color);
    font-size: 2.2rem;
    margin-bottom: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 15px;
}

.header p {
    color: #6c757d;
    font-size: 1.1rem;
}

.dropzone {
    border: 2px dashed #ced4da;
    border-radius: var(--border-radius);
    padding: 40px 20px;
    text-align: center;
    cursor: pointer;
    transition: var(--transition);
    margin: 25px 0;
    background-color: #f8f9fa;
}

.dropzone:hover {
    border-color: var(--accent-color);
    background-color: rgba(72, 149, 239, 0.05);
}

.dropzone.active {
    border-color: var(--primary-color);
    background-color: rgba(67, 97, 238, 0.1);
}

.dropzone-content i {
    font-size: 3.5rem;
    color: var(--primary-color);
    margin-bottom: 20px;
}

.dropzone-content h3 {
    margin-bottom: 10px;
    color: var(--dark-color);
    font-size: 1.3rem;
}

.dropzone-content p {
    margin: 15px 0;
    color: #6c757d;
    font-size: 1rem;
}

button {
    background-color: var(--primary-color);
    color: white;
    border: none;
    padding: 15px 30px;
    border-radius: var(--border-radius);
    cursor: pointer;
    font-size: 1rem;
    font-weight: 600;
    transition: var(--transition);
    display: inline-flex;
    align-items: center;
    gap: 10px;
}

button:hover {
    background-color: var(--secondary-color);
    transform: translateY(-3px);
    box-shadow: 0 5px 15px rgba(67, 97, 238, 0.3);
}

button:disabled {
    background-color: #adb5bd;
    cursor: not-allowed;
    transform: none;
    box-shadow: none;
}

#selectFilesBtn {
    background-color: white;
    color: var(--primary-color);
    border: 2px solid var(--primary-color);
    padding: 12px 25px;
}

#selectFilesBtn:hover {
    background-color: var(--primary-color);
    color: white;
}

.options {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 20px;
    margin: 25px 0;
}

.option {
    display: flex;
    flex-direction: column;
}

.option label {
    margin-bottom: 10px;
    font-weight: 600;
    color: #495057;
    display: flex;
    align-items: center;
    gap: 8px;
}

.option input, .option select {
    padding: 12px 15px;
    border: 1px solid #ced4da;
    border-radius: var(--border-radius);
    font-size: 1rem;
    transition: var(--transition);
}

.option input:focus, .option select:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(67, 97, 238, 0.2);
}

.file-info {
    background-color: #f8f9fa;
    border-radius: var(--border-radius);
    padding: 20px;
    margin-bottom: 20px;
    display: flex;
    align-items: center;
}

.file-details {
    display: flex;
    align-items: center;
    gap: 15px;
    width: 100%;
}

.file-details i {
    font-size: 2.5rem;
    color: var(--primary-color);
}

.file-details h4 {
    margin-bottom: 5px;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.file-details p {
    color: #6c757d;
    font-size: 0.9rem;
}

.actions {
    display: flex;
    gap: 15px;
    margin-top: 30px;
}

#downloadBtn {
    background-color: var(--success-color);
}

#downloadBtn:hover {
    background-color: #3aa8d8;
}

.progress-container {
    margin-top: 25px;
    background-color: #e9ecef;
    border-radius: var(--border-radius);
    height: 20px;
    position: relative;
    overflow: hidden;
}

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

.progress-text {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    color: white;
    font-weight: bold;
    font-size: 0.8rem;
    text-shadow: 0 0 3px rgba(0, 0, 0, 0.3);
}

.status {
    margin-top: 20px;
    padding: 12px;
    border-radius: var(--border-radius);
    font-weight: 500;
    text-align: center;
    display: none;
}

.status.success {
    background-color: rgba(76, 201, 240, 0.1);
    color: var(--success-color);
    border: 1px solid var(--success-color);
    display: block;
}

.status.error {
    background-color: rgba(247, 37, 133, 0.1);
    color: var(--error-color);
    border: 1px solid var(--error-color);
    display: block;
}

@media (max-width: 768px) {
    .converter-card {
        padding: 30px 20px;
    }
    
    .header h1 {
        font-size: 1.8rem;
    }
    
    .options {
        grid-template-columns: 1fr;
    }
    
    .actions {
        flex-direction: column;
    }
    
    button {
        width: 100%;
        justify-content: center;
    }
}