Set default text and background colours

Some elements in the design have text colour without background colour. Setting a global background colour should be enough with current text colours.

I wonder however if `var(--white)` is really necessary, instead of `white`.

css/index.css

@@ -16,6 +16,8 @@ body {
 	padding: 0;
 	margin: 0;
 	font-family: sans-serif;
+  color: var(--darkgrey);
+  background-color: var(--white);
 }
 p:last-child {
 	margin-bottom: 0;