How can I eliminate the gray border around Jupyter/ipython notebooks in my browser?

Update 2019/02/18: Instead of doing the below, I recommend installing jupyterthemes. These notebook themes are awesome and pretty and easy to use, and they eliminate the gray border.

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Original Post:

So after using "Inspect Element" on a notebook and learning an iota of CSS, it seems the following will work

from IPython.core.display import display, HTML
display(HTML(
    '<style>'
        '#notebook { padding-top:0px !important; } ' 
        '.container { width:100% !important; } '
        '.end_space { min-height:0px !important; } '
    '</style>'
))

where the top line removes the gray margin at the top, the middle line removes the side margins, and the bottom line removes the gray margin at the bottom.

The content in-between <style>, </style> can also be added to the custom.css file in ~/.jupyter/custom/ following this thread; my file contains the lines

/* Modifications to notebook format  */
#notebook { padding-top:0px !important; } /* eliminate top gray */
.container { width:100% !important; } /* eliminate side gray */
.end_space { min-height:0px !important; } /* eliminate bottom gray */