Hi @s a new version of the theme is already being developed focusing on a more mobile friendly layout.
The Vote and Answer boxes width on Desktops were originally created with that specific width thinking on the future, so whether or not an item has too many votes, it all fits as the same size for all the list items.
Otherwise it would look shorter for ones and longer for others depending on the text and counter length. But this might also change and adapt this new concept of the mobile design, showing just the number and its icon in front.
Modifying theme styles
The font is Roboto, the font of Material Design. But if you really want, all of this can be changed, the font, the menu bar color and text color trough CSS, but as I said a new version is coming out soon so don't make any changes yet. Also because I'm thinking on a way for you to implement your custom styles without constantly overwriting them on each theme update.
Increasing sidebar width
Originally the focus here, was the main area size, to fit a Google Adsense ad banner of 728px, leaving the sidebar only for important information, without ads nor advertisement saturation for the user. But I understand people might wanna use both, the 720px main area and the 300px ad on the sidebar, so I will consider reshaping that.
Regarding the other question #
Yes, I'm aware of the missing icons, and will be implemented on this next update.
The answers alignment were purposely created with that alignment to highlight the main post (the question) as the main post of the "tree", this will be realigned as well.
This theme is a constant process of creating, bending and shaping things out to reach its best looks and feels, so everyday new ideas and concepts are being thought to make it better.
Thank you for your purchase and contribution to make it better.