/// <summary>
/// Returns a keyframe rule corresponding to the given key.
/// </summary>
/// <param name="key">A string containing an index of the keyframe to be returned, resolving to a number between 0 and 1.</param>
/// <returns>The keyframe or null.</returns>
public ICssKeyframeRule Find(String key)
{
return(_rules.OfType <ICssKeyframeRule>().FirstOrDefault(m => m.KeyText.Equals(key, StringComparison.OrdinalIgnoreCase)));
}
public CssKeyframeRule Find(String key)
{
return(_rules.OfType <CssKeyframeRule>().FirstOrDefault(m => key.Isi(m.KeyText)));
}