Site break when enabling subtheme

Installed the latest version yesterday (1.20) and created a subtheme following the " Opigno theme customisation create a subtheme" video. When I enable the subtheme the homepage when logged out is broken. Here is my file: name = Sopig description = Sopig theme core = 7.x base theme = platon stylesheets[all][] = css/override.css I've enabled and set my subtheme as default. I have resaved settings and clear cached. As you can see the homepage is broken. What can I do?