A div can be considered an all purpose container, that can be decorated in a number of ways. Almost any aspect of it's appearance may be changed, including coloured borders, fills and image backrounds. Divs are probably the most used element on most pages, as they are used in defining the overall layout, and are so flexible, it's easily possible to have a page that only contains divs, in fact, The Escapers home page is almost entirely divs. Divs can be positioned 'absolute', which means it is positioned at an exact location on the page, and is unaffected by other content. They can also be positioned 'relative', which means their position can change depending on contents, for example, you can position a div at the end of some text, and if the text expands, the div will move to create room for it. You can apply actions to divs to create buttons, or areas that change when the mouse passes over them.
You can either apply a color fill as an override, or define it in a CSS style.
Create a new div by choosing 'Div' from the 'New Element' toolbar menu, and make sure it is selected. Open the 'Inspector' from the 'Window' menu, and make sure the 'Fill' section is enabled. Within the Fill section there is a color well, click on this and choose the color you want from the color palette. Make sure the opacity is above 0%, or you won't see any change.
The process of changing the color in the CSS style is exactly the same as the above, but instead of using the 'Inspector', we need to edit the CSS style. If you haven't already, we need to setup a CSS style, this is described in
Make sure the 'Fill' section is enabled in the CSS style, and use the color palette to change the color. If you don't see any difference, make the sure the Div does not override this property in the 'Inspector'. You can use the opacity slider in the color well to make your fill semi-transparent, but be aware, that very few web browsers actually support semi-transparent colors.