How can i set the same background color on all linked html webpages

Im attempting to style my HTML web page and applying the same background color to all of them. I have successfully linked my separate style sheet as other elements are working however when I removed the style from my individual pages and moved it to my style document, all pages are showing as white. Please let me know what I'm doing wrong with this not translating to my website. Thanks!

body
{
    background-color:grey;
}