AngleSharp by Florian Rappl

<PackageReference Include="AngleSharp" Version="0.8.7" />

.NET API 1,175,040 bytes

 BoxModel

public enum BoxModel
An enumeration with the various box sizing models / clip or origins.
namespace AngleSharp.Dom.Css { public enum BoxModel : ushort { BorderBox, PaddingBox, ContentBox } }