I think it would be pretty useful if the copilot automatically set the scrollbar thumb color to say, brand-9, and the thumb:hover to brand-11
Same for html selection color, it would use brand-9 by default.
Could be a nice little addition that no editor has, either as a toggle or other selector in the Copilot palette or in a Miscellaneous tab.

I'll share with you the CSS I typically use for scrollbars styling

/* Custom selection color */

::selection {
background: var(--hcl-brand-9) ; / WebKit/Blink Browsers /
color: black;
}
::-moz-selection {
background: #ffc20e; / Gecko Browsers /
color: black;
}
/ Custom scrollbar /

/ Works on Chrome, Edge, and Safari /
*::-webkit-scrollbar {
width: 10px;
}

*::-webkit-scrollbar-track {
background: transparent;
}

*::-webkit-scrollbar-thumb {
background-color: var(--hcl-brand-9);
}

::-webkit-scrollbar-thumb {
background: var(--hcl-brand-9);
border: 6px solid transparent;
}

::-webkit-scrollbar-thumb:hover {
background-color: var(--hcl-brand-11);
}