I know this topic already exists in the 'Solo' category but i have the same problem. I'd like to have my menu on mobile version on a tablet and on phone. It's ok on my phone but not on my Ipad. I placed the recommended css in my custom scss file: (with the @import "dependencies"; at the top)

#g-header {
[class*="size-"] {
@include breakpoint(tablet-range) {
@include flex-grow(0);
@include flex-basis(100%);
max-width: 100%;
}
}

.g-logo {
@include breakpoint(tablet-range) {
display: block;
text-align: center;
}
}
}