Revert "Revert "Merge branch 'tidied-markup' into gh-pages""

This reverts commit 4a9c9e9ebabe97bcd2abcb16c53dcfd1ff33db2d.
Revert "Revert "Revert "Merge branch 'tidied-markup' into gh-pages"""

This reverts commit ad1199a8ccced336382388909fd752e546e6e899.