How to enable the sidebar and create a default Light theme?

[Canapin (Coin-coin le Canapin)]

If by “full width” you mean enlarging your forum’s content to it takes more width on your screen, you need to add this to your CSS:

How to increase width of topic

Good news, this is the case now. In a theme the content width of a topic can be increased with a little CSS: :root { --topic-body-width: 1000px; } That’s it! no overlap. Note that the max-width is still constrained by Discourse’s overall max-width, so if you want to go to an extreme and do something like: :root { --topic-body-width: 2000px; } you’ll also need to increase --d-max-width, which defaults to 1110px :root { --d-max-width: 3000px; --topic-body-width: 2000px; }

Having a site in full-width isn’t always a good thing though, it depends on the content.