I've set the background color to #FFF on the one course child theme, but it isn't taking. So the course page is still using the #F6F6F6 background color. I'm not sure why it isn't taking. Here's the page link: https://learn.level360.co/course/one-course/
Go to wp-admin->appearance->customiser->add custom CSS-> add these lines and save.
http://prntscr.com/dcrh1d
.single-course .course_header .container {margin-top: 80px !important;}
To change the background color
Try using this css
{background-color:#fff !important;}
You can also refer to the theme guide:
http://vibethemes.com/envato/wplms/documentation/theme-guide.html#customiser-theme
http://vibethemes.com/envato/wplms/documentation/theme-guide.html#customiser-body
http://vibethemes.com/envato/wplms/documentation/theme-guide.html#customiser-typography