Semantic kbd markup for keyboard input
Restore spacing between export button text and caret
Modify kbd styles
Merge pull request #120 from ahbeng/kbd

Semantic kbd markup for keyboard input
Override $screen-xs-min to be 400px, add and use xxs responsive utility classes
Retain full label for normal sems and shorten special term labels to 'ST'

For bigger targets on mobile, as special term timetables hardly need to be planned