Ok, here's the code I am using
.post {
padding-left: 8px;
padding-bottom: 90px;
padding-right: 8px;
padding-top: 20px;
background-image: url(bottomstripes.png), url(top_left.png), url(top_right.png), url(bottomleft.png);
background-position: right bottom, left top, right top, left bottom;
background-repeat: no-repeat;
border-left-style: none;
border-bottom-style: none;
border-right-style: none;
border-top-style: none;
margin-left: -10px;
margin-bottom: 20px;
background-color: #c7c7c7;
And it shows up without the background images in Firefox. It shows up with the bg images in Safari. Validation says there's too many bg images, but I am not sure how to fix this, especially since it works in Safari.