Revert "overflow: hidden"
Revert "overflow: hidden"

This reverts commit 7b2a486b71df86a37782371ba158b824e7f24b0e.

JING-TIME/ustc-course,JING-TIME/ustc-course,JING-TIME/ustc-course,JING-TIME/ustc-course,JING-TIME/ustc-course