BuddyPress.org

@opensourcelover

My first thought is that it’s a text-shadow causing the blur effect. As the adminbar is called via the footer, try adding the following to your CSS:
`div#footer {text-shadow:none;}`

BTW, you really should create a child-theme rather than using bp-default, otherwise any changes you make to the default theme will be lost when you upgrade Buddypress. See here to learn how:
https://codex.buddypress.org/theme-development/building-a-buddypress-child-theme/