I am not that familiar yet – I just need to get my site up and going – thanks will look into how to make child theme once up and going!
I have been trying for 2 days after tried the mods for twenty twn but gave up!!! and eventually found the default.css
You will find the default.css in the following directory – just use your domain name and wordpress installation directory.
yourdomain.com/your wordpress installation directory/wp-content/plugins/buddypress/bp-themes/bp-default/_inc/default.css
Rename defaul.css to original_default.css hust in case something goes wrong so that you can revert!
I downloaded it to my pc and then with notepad++ and saved it locally as default.css
about 1/3 down line 508 change the colour code to what you want for displayed links and line 512 change the hover colour to what you want.
Save the file and upload it to where you downloaded it from!
I had a real problem seeing the light blue and changed it to dark blue and the hover link to red. Now I can see it fine!!!