XF 1.5 Change theme on the sidebar

[Betclever]

Hello,

I would like to use the same function which is present on PHPBB3 (see gif) so change the theme on the sidebar...
I don't know if it is possible to do this even if I know how to make child themes...

https://gyazo.com/bb0a556920eaf22b1ed44e6e8815d882

Thank you

 

[EQnoble]

Yes it is possible to do but you are asking in the wrong place as you are asking about style customization/development.