I am using the text widget to place a side menu on my homepage but it doesn't work very well responsively. Although it looks fine on a mobile, on a tablet in portrait it looks dreadful. It doesn't span the width of the screen but merely sits in the middle underneath the intro text. Ideally I would like it to remain the same as on desktop and just change for mobile viewing. Can the media queries be changed in the custom css feature to combat this and if so how could I do it? The theme I am using is SELA.
The blog I need help with is grayshottheritage.com.