Hi Timo,
To display mobile version to be wide layout while setting narrow layout go to Appearance -> Customize/Theme Options -> Design Options Tab -> Custom CSS paste the following CSS code and Click on save button:
@media only screen and (max-width: 1078px) {
.narrow-layout .wrapper {
width: inherit;
}
}
@media only screen and (max-width: 767px) {
.narrow-layout .wrapper {
width: inherit;
}
}
@media only screen and (min-width: 480px) and (max-width: 767px) {
.narrow-layout .wrapper {
width: inherit;
}
}
Thank you!