What am I doing wrong? THIS TIME :)

Hey everyone,
So I was playing around with codes and I had my background color prefect for the longest time then I went and entered a code into the CSS box I had my body code in and for some reason my entire site went to a blueish gray. This is the second time I've had this problem so I have two questions.

1)Where would I put this code:

body {
  background: rgb(43, 48, 56)!important;
  background: -moz-radial-gradient(center, ellipse cover, rgba(43, 56, 1) 1%, rgba(2, 8, 20, 1) 100%)!important;
  background: -webkit-gradient(radial, center center, 0px, 100%, color-stop(1%, 1)), color-stop(100%, 1)))!important;
  background: -webkit-radial-gradient(center, 1) 100%)!important;
  background: -o-radial-gradient(center, 1) 100%)!important;
  background: -ms-radial-gradient(center, 1) 100%)!important;
  background: radial-gradient(center, 1) 100%)!important;
  filter: progid:dximagetransform.Microsoft.gradient( startcolorstr='#2b3038', endColorstr='#020814', GradientType=1 )!important;
}

2)Why does it sometimes go to grayish blue when I am doing this.

Last time I had this issue I started all over and I rather not do that this time since I got pretty far and almost to the put where I wanted to unveil everything. I know I could just make a background image with that color but from what I hear CSS is quicker and the less images you have more css you have your site is faster that way. I'm a beginner in all this coding so forgive me if I am wrong on that. Lastly you can see the color I have on my current website that is still in legacy here www.k-ophotography.com

Thanks for the help.

KO