I am using the below option to create some custom select boxes

https://www.w3schools.com/howto/howto_custom_select.asp

However this option does not allow to create titles or headings which are disabled from the selectable options.

With the standard combo/list box option i use to create these using for example with a style option per item below which would stand out:

<option value="10600" style="font-weight: bold; color: #000000; background-color: #ffffff;" disabled >Colours</option>

The other options would be as per below:

<option value="10601">Blue</option>

Would anyone be able to confirm the best way to intergrate titles or headings within the CSS listbox/dropdown area with the titles being non-selectableand in a different colour or format?

Thank you