css:

.check-box {  margin: 0 10px;  cursor: pointer;}.check-box:before {  content: '';  background: #ffffff;  display: inline-block;  width: 8px;  height: 8px;  border: 2px solid #fff;  border-radius: 100%;  cursor: pointer;  vertical-align: bottom;}.check-box.checked:before {  background: #9ec707;}

html:

    
             选择操作系统：        
                 CentOS                
                 Ubuntu / Debian