Squashed 'slides/' content from commit 67b1dee

git-subtree-dir: slides
git-subtree-split: 67b1dee73a2131f8dc342fce5880ca758971607e
Merge commit '20ff01cdeb084ea8ab100fe3cc42234397015ba9' as 'slides'
not using reveal themes on make serve
reverted to light theme with black text