Misc. UI Fixes

Just a few tweaks I noticed when running on my browser!

1. Should be able to tap entire date cells in the sidebar to show question, right now only tapping the date text works
2. Change question title text color when creating a question to black
3. Can you double check all the fonts? it looks like there are some inconsistencies with bolding and colors from the designs

Start by reproducing the three UI issues in a browser: test the full date cells in the sidebar, inspect the question title while creating a question, and compare font weights and colors with the designs. Done means the entire date cell is tappable, the creation title uses black text, and the visible font inconsistencies are resolved.

索引モデルが issue の本文から書いたものです。