Custom breakpoint not working on each browser

Hi,
on this site https://entwicklung.silexa.com/growler-und-bottle-filler-en/ we have a header section with custom class which will be displayed on screen sizes bigger than 1300 px. Below there are 2 sections with custom classes displayd on screen sizes below 1300 px. This works fine with the following css-code:

@media only screen and (min-width: 1300px) {
#headermobile1 { display: none !important; }
#headermobile2 { display: none !important; } }
@media only screen and (max-width: 1300px) {
#headerdesktop { display: none !important; } }

in Firefox, Edge, Safari on Smartphone, but not on Chrome or Safari on Tablet.
Any solution?
Thanks
Stefan