@kyle: Remove that background image and background color from your customizer and then add the following css in “Appearance => Theme Options => Custom CSS” box:
body {
background: #BA3027; /* Show a solid red color for older browsers */
background: -moz-linear-gradient(#BA3027, #000000);
background: -o-linear-gradient(#BA3027, #000000);
background: -webkit-gradient(linear, 0% 0%, 0% 100%, from(#BA3027), to(#000000)); /* older webkit syntax */
background: -webkit-linear-gradient(#BA3027, #000000);
}
Yes, but this custom background in customizer is from WordPress core so it’s not good practice to modify core. If the WordPress core adds it then it will be there.