Recently a bug was introduced when the admin sidebar section was made bold.
When the admin sidebar is disabled, we display the original sidebar in the admin panel. In that case, an incorrect CSS rule is executed.
```CSS
.admin-area .sidebar-wrapper {
background-color: var(--d-sidebar-admin-background);
.sidebar-section-header-text {
font-weight: bold;
}
}
```
Bug in this PR: https://github.com/discourse/discourse/pull/26801
To solve it, a custom CSS class with a panel key was added which will allow granular customisations.