Each first nested css rule isn't highlighted properly

Type: Bug

1. Create a css file
2. Add a rule
3. Nest a few rules inside

Example:

.useful-class {
    .rule-without-highlight {
        background-color: red;
    }

    .rule-with-highlight {
        background-color: green;
    }

    .another-rule-with-highlight {
        background-color: green;
    }
}

useful-selector {
    selector-without-highlight {
        background-color: red;
    }

    selector-with-highlight {
        background-color: green;
    }

    another-selector-with-highlight {
        background-color: green;
    }
}

:first {
    :first-child {
        background-color: red;
    }

    :nth-child(2) {
        background-color: green;
    }

    :last-child {
        background-color: green;
    }
}

Example output:

VS Code version: Code - Insiders 1.98.0-insider (21525b01bf68bf9250cb856f192628fffc449234, 2025-02-11T05:04:43.535Z)
OS version:
Modes:

System Info: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:135.0) Gecko/20100101 Firefox/135.0

Reproduce the nested-rule examples in VS Code and inspect the CSS TextMate grammar in this repository, which provides the syntax highlighting. Compare the first nested rule with subsequent rules and verify the behavior for class selectors, element selectors, and pseudo-selectors. Done means each first nested rule receives the same highlighting as the following rules.