[Alison Nichols]

You can do it. First go to:
https://www.color-hex.com/

type in the hex code for your color. It’ll come up with the RGB, HSL, HSV and CMYK color values.

In FCP:
Under the Controls tab in the Viewer, there are 3 tools you can click
on that change color- eye dropper, some rainbowy thing, and a color
square. Click on the square.It will bring up a Colors palette. Click
on the second option from the left up top. Change the drop down to RGB
Sliders, enter the RGB info and voila. If you drag that color to the
bottom row of white squares, it will now be in your FCP palette. Works
somewhat similarly in all the other FPC apps too.

Cheers,
Alison