style: Increase contrast and realign blue to PF4
style: Increase contrast and realign blue to PF4

Closes #286
martinpitt/cockpit-project.github.io,cockpit-project/cockpit-project.github.io,martinpitt/cockpit-project.github.io,cockpit-project/cockpit-project.github.io,cockpit-project/cockpit-project.github.io,cockpit-project/cockpit-project.github.io,martinpitt/cockpit-project.github.io,martinpitt/cockpit-project.github.io