Hi Dominik,
It's becuase there is default padding there, of course you can force to reduce it
@media screen and (max-width: 780px) {
.com_spsimpleportfolio #sp-component,
.com_spsimpleportfolio .sppb-row-column {padding-right: 0; padding-left: 0;}
}
and with that CSS code should be removed on all Portflio pages. Just use it inside custom.css or Template Options > Custom Code > Custom CSS
But then padding inside used addons you have to add manually.
OR you can use more extended CSS instead
@media screen and (max-width: 780px) {
.com_spsimpleportfolio #sp-component,
.com_spsimpleportfolio .sppb-row-column {padding-right: 0; padding-left: 0;}
.sppb-addon.sppb-addon-text-block {padding: 0 15px;}
}