Minor changes to Guru page

Minor changes to Guru page - still not satisfied with either the content
or UI - will need a complete rewrite.
Better appearance on Mobile

Better appearance on Mobile using MQs - general stylesheet that affects
all pages.
MQs for Home page

MQs for elements in Home page only (in page style tag).
MQs for Courses

MQs for Courses page - minor table cell alignment issue corrected.