There are no clearly defined rules for which characters to use as title separators. However, document titles should definitely not contain punctuation used for decorative purposes, for instance “:: Title ::” or “…== Title ==…”.

Font size specified in a relative unit like em or percent lets text resizing work in all browsers.

If we were to comply with the WAI WCAG guidelines to this particular assessment it would have been necessary to amend the assessment to add ALT text to the images. However doing so would have changed the pedagogic purpose of the assessment and would not have tested that the students have acquired the stated learning outcomes.