Thames problems

@nicol since some recent changes, my colours are all a bit Wes Anderson.

I've fixed the amber ones. Working on the red/pink ones.

It seems that --crm-c-alert is used for

• text: on .status-removed; the no-entry-type icon used when an email is on hold; in Form builder
• background: on btn-danger;
• border-color: on notification errors

I've fixed these in the PR coming, but I think using one variable for text, background and border is likely to lead to this arising again.