There is a css error in the new nopClassic\Content\styles.css:
/* ONE PAGE CHECKOUT */
.opc .buttons{margin-top:0;padding-top:2em;}
.opc .buttons .back-link small{display:none;}
.opc .buttons .back-link a background:url(images/arrow-up.png) 0 50% no-repeat;padding-left:20px;}
The line above is missing the opening "{" and should be replaced with:
.opc .buttons .back-link a{background:url(images/arrow-up.png) 0 50% no-repeat;padding-left:20px;}
Thanks for the new release, keep up the good work!