Monaco-Editor: CSS syntax validation for CSS nesting

[josch0]

Winter CMS Build

1.2

PHP Version

8.4

Database engine

MySQL/MariaDB

Plugins installed

None

Issue description

When using WinterCMS 1.2.12, the CSS editor marks nested CSS classes as errors.
Although the specification for nested CSS is still in the draft stage, it has been supported by all common browsers for a few years now.

It would be desirable for Monaco to also support widely used CSS syntax, even if it is not yet in its final state.

https://caniuse.com/css-nesting

Steps to replicate

Add nested CSS classes:

header {
    color: green;

    & h1 {
        color: red;
    }
}

Workaround

No response