Well, it IS possible but it won’t be as easy depending on what you want to achieve.
“col-md-4” is the sidebar’s grid class which roughly means “It’s a column and on medium sized screens it will take up 4 spaces.
This is a basic responsive grid which makes the auto adjusting on smaller screens possible. This is great an all but that makes it harder to finetune.
You could change the “col-md-4” to “col-md-3” or 2 and it would be smaller, but you have to change the content’s class from col-md-offset-4 to col-md-offset-3 or col-md-offset-2 accordingly. Then you might have to adjust the
font-size of .site-title
which is harder since you will have to edit the css in all the media-queries.