In FF and Safari floating is a mess now. I removed float:left for "coursebox" to get the page working in all browsers. It is a single element and should not need floating.
.weeks-format .block_calendar_month .minicalendar th,
.topics-format .block_calendar_month .minicalendar th,
.weeks-format .block_calendar_month .minicalendar td,
-.topics-format .block_calendar_month .minicalendar td, {
+.topics-format .block_calendar_month .minicalendar td {
padding: 0.1em 0 0.1em 1px;
}
.weeks-format #middle-column ,
.coursebox {
width: 100%;
- float:left;
+ /* float:left; */
margin-bottom: 15px;
border-width:1px;
border-style:solid;