Disabling Main Category Links

Hi Christine:
Awhile ago you gave me this code to change the Category Name color on the navigation menu:
.main-navigation li a {
color: #000;
}

.main-navigation li li a {
color: #bbb;
}

This worked fine. I would now like to disable the main category links.

This is the code I tried with the above but it didn’t work the way I would like.
.main-navigation li a {
pointer-events: none;
}

Here is my website: https://www.gallery24.us/mobile
Any help is appreciated.

Thanks,
Vic