Improve default text contrast, or provide ability for users to adjust theme

CiviCRM employs relatively small font sizes, pale link colours, and a lot of greys and browns. In places this makes using CiviCRM hard on the eyes for users over the age of about 40.

Would recommend either relatively minor tweaks to the default theme to adjust contrast (darker fonts, especially in the default link colour).

A slightly more ambitious project would be to allow the user to make modest adjustments to the colour scheme, or provide a 'high contrast' theme.