Revert "Back to horizontal layout."

This reverts commit ded9cdfede884e7c8ade89b4ca285fce999e2741.
Revert "Even more tweaks, focus on responsiveness."

This reverts commit f88a0459c05b321de25c665e5024c8ab191275cc.
Revert "More style tweaks."

This reverts commit 65e4dde0f01c3a654947781914d570cd808e01d0.
Revert "First redesign pass (targeting sidebar)."

This reverts commit d7a0d9cf0f05b138c8f605c5a69eabe913388e20.