Currently using the blue-sidebar theme however on some of my articles any text that is formatted in "Header 2" style (i use JCK Editor) appears white and therefore not readable using the theme. How can I correct this to make the text #777777 colour ?

Hi there,
please dont use inline css styles. The header font color must be setup in customizer.
Or you can override in the css/custom.css

.uk-panel-diebar h3 {color:#ff0000 !important}