.college_ry{height:50px;overflow: hidden;}
.last{line-height:50px;color: #fff;cursor: pointer;font-size:14px;position: relative;width: 17px;height: 17px;background-color: #cacaca;border-radius: 9px;margin-top: 16px;}
.college_ry.r_open{height:auto;}
.last i{}
.last i:before {position: absolute;content: "";width: 6px;height: 1px;background-color: #fff;top: -4px;bottom: 0;margin: auto;-webkit-transform: rotate(45deg);transform: rotate(45deg);left: 0;right: 0;}
.last i:after {position: absolute;content: "";width: 6px;height: 1px;background-color: #fff;top: 0;bottom: -4px;margin: auto;-webkit-transform: rotate(-45deg);transform: rotate(-45deg);left: 0;right: 0;}
.last.m_open i:before {top: 0;bottom: 0;left: -4px;right: 0;}
.last.m_open i:after {top: 0;bottom: 0;left: 0;right: -4px;}