Modify current .net web app

i have an alreday built app i need to do very simple changes and it must be done today
I want to switch the look to be like the attached image -
make sure the layout to fit on mobile and also on desktop
the code of connection to database is written all what you have to do is just the layout
the current website is
https://cube-its.net/retro
I want it to be like the attached image - the layout
the functionality must stay the same