kas1983
In the same script, add these lines
.dc-column{
border: 2px solid red !important;
}
The complete script looks like this; I added " !important " for the previous border, without it, it might not work
<style>
.dropdown-content{
width: 50vw !important;
border : 2px solid red !important;
}
.dc-column{
border: 2px solid red !important;
}
</style>
Please note, on your website, I see that there are two identical lines
.dropdown-content{width: 30vw !important;}
EDIT: You can change the colors