Text Box

Into the header?

No, in the main page, I’d like to put the writing:

a-accessibilty

etc

Into a coloured box!

<div class="box" style="height:_px;width:_px;flot:left;border:_px solid green;border-radius: _px _px _px _px;background-color:orange;padding:_px">

<!-- element inserted here will be inside a box with an orange background color, and a green border -->

</div>

there are so many other css style tags you can add in style="" , just try to put what you want to be inside a box , put the code between the divtag above . try to change your measure , height and width, colors, border options etc ..