Fix layout (Issue #78)

[rudolfovic]

Switching the layout to flex. On my site, flex-basis was not necessary but on webjeda.com the sidebar ended up too narrow for some reason. The width can be increased further with flex-basis, however, for some reason does not exactly correspond to computed width.

Closes #78.

[rudolfovic]

I applied these changes exactly in the browser on webjeda.com/online-cv and it worked fine (as in the width stayed exactly the same and on xsmall devices layout switched to column) for me so I am not sure what the problem is exactly.

[sharu725]

stale