Menu button opening a empty page on mobile

[BrunoJarvik]

When you go to ecoperiod.pl on mobile and click on the menu button a empty slider opens. 

I imported this theme and the issue was already there. 

Can anyone help please?

[BrunoJarvik · Accepted solution]

Found the solution:

theme.liquid > find </body> at the bottom of the code > put this code above </body> : 

<style>
@media screen and (max-width: 767px) {
div#menu-drawer {
height: 100vh!important;
}
.menu-open div#menu-drawer {
transform: translate(0%)!important;
visibility: visible!important;
}
}
</style>