Good afternoon msens,
first of all the good news:
The solution to your problem would be to adjust the following css class:
.sf-menu li li li a {
padding-left: 44px;
}
These 44px are the whitespaces you encounter.
As I do not know if you have access to or can alter the respective css file (in this case it would be the main-style.css; line 206), you could adjust this value via different ways.
First of all you should keep in mind that adjusting the style.css, maybe/probably even the main-style.css here, can be overwritten with the next update. Thus your adjustments will be overwritten, too.
To avoid this you could either make use of the advantages of a child theme.
Or if your theme offers a section named in the likes of “custom css” or “CSS styles” you could copy and paste the lines I entered above and adjust the padding-left value to your needs right there. If you’re not sure, just have a look at your WordPress dashboard somewhere around the “Apperance” tab or the “Settings” tab. Sadly it’s something that can differ from theme to theme.
Hope you can use any of the information.
Best regards
Ronny.