GUIColor

https://odininspector.com/attributes/guicolor-attribute

[GUIColor(0.3f, 0.8f, 0.8f, 1f)]
public int ColoredInt1;

[GUIColor(0.3f, 0.8f, 0.8f, 1f)]
public int ColoredInt2;

[ButtonGroup]
[GUIColor(0, 1, 0)]
private void Apply()
{
}

[ButtonGroup]
[GUIColor(1, 0.6f, 0.4f)]
private void Cancel()
{
}

[InfoBox("You can also reference a color member to dynamically change the color of a property.")]
[GUIColor("GetButtonColor")]
[Button("I Am Fabulous", ButtonSizes.Gigantic)]
private static void IAmFabulous()
{
}

[Button(ButtonSizes.Large)]
[GUIColor("@Color.Lerp(Color.red, Color.green, Mathf.Abs(Mathf.Sin((float)EditorApplication.timeSinceStartup)))")]
private static void Expressive()
{
}

private static Color GetButtonColor()
{
    Sirenix.Utilities.Editor.GUIHelper.RequestRepaint();
    return Color.HSVToRGB(Mathf.Cos((float)UnityEditor.EditorApplication.timeSinceStartup + 1f) * 0.225f + 0.325f, 1, 1);
}C#