V.9 updated 8.3 theme cause cms interface text to be very small

I have successfull updated our 8.3 theme to run with version 9. Everything works fine, exept that the cms interface text is very very small. Where can I change that?
thank you very much for help

That’s generally caused by your theme’s styles too broadly or aggressively applying to the entire page, instead of specifically to your theme’s layout and content.

For more general text styles, like headings, paragraphs, labels, etc, those should be wrapped in a class that is only around the page content.

So instead of something like this:

h3 {
color: orangered;

you would do something like:

.ccm-page h3 {
color: orangered;

That then guarantees that that styling won’t impact the actual Concrete interface.
The .ccm-page class is suggested as it’s automatically added to all pages (if your theme is built correctly), so you know it’s always present. But you can also use some other class that is in your theme that you know wraps around the content to style.

What you’ll need to do is inspect on the interface where the font size is incorrectly small, work out what style is making that happen, and then adjust with prefixing .ccm-page accordingly.

If your Concrete interface is small in edit mode, that probably means you have set font-size attribute on html tag.
You can check it in Chrome Inspector.

By default font-size on html tag is set to 16px in most browsers.
In old days some developers liked to set it to 10px for easy conversion between px and rems, Bootstrap 3 had font-size set to 14px I believe.

Bootstrap5 in Concrete 9 uses mostly rems for sizes (which are relative to font-size in html tag). So removing font-size from html tag or setting it to 16px should help (you will find it in your css/scss/less files, it can be coded explicitly on html tag or somewhere as variable).

Caveat is, if there was something coded in rem units in your theme, it has to be adjusted accordingly.

I changed font-size for the html tag and everything looks normal.

Thank you both, happy weekend.