AngleSharp by Florian Rappl

<PackageReference Include="AngleSharp" Version="0.8.4.1" />

.NET API 1,229,312 bytes

 ICssGroupingRule

public interface ICssGroupingRule : ICssRule
Represents any at (grouping) CSS rule.

Gets a list of all CSS rules contained within the grouping block.

int Insert(string rule, int index)

Used to insert a new rule into the media block.

void RemoveAt(int index)

Used to delete a rule from the media block.