GeneratePress Header

I have a problem with a site I was given to manage. I didn’t make the site and I’m not familiar with generatepress and metaslider.
Basically a slide was inserted with metaslider on the header. As you can see the slide does not fill the header container well.

Thanks in advance for any kind of help, sorry for the English, I am using a translator

I will also transcribe the php code for you:

<?php
if(is_front_page()) {
echo do_shortcode('[metaslider id="8"]');
echo "<style> .flexslider .slides{height:600px;} </style>";
}
$id = get_the_ID();
if($id==26){
echo do_shortcode('[metaslider id="25"]');
}
if($id==201){
echo do_shortcode('[metaslider id="334"]');
}
if($id==60){
echo do_shortcode('[metaslider id="336"]');
}
if($id==137){
echo do_shortcode('[metaslider id="338"]');
}
if($id==75){
echo do_shortcode('[metaslider id="557"]');
}
?>

The page I need help with: [log in to see the link]