lib/html/isabelle.css

 .theories { background-color: #F0F0F0; padding: 10px; }
 .sessions { background-color: #F0F0F0; padding: 10px; }
 
 .name     { font-style: italic; }
 .filename { font-family: fixed; }
-
-/* hide hr for this style */
-hr { height: 0px; border: 0px; }
 
 
 /* basic syntax markup */
 
 .hidden, hidden { font-size: 0.1pt; visibility: hidden; }