第一种

.div{


position: absolute;
top: 0px;
right: 0px;
display: inline-block;
width: 0;
height: 0;
border: 10px solid transparent;
border-bottom-color:#333;


}
.div>span::after{
content: ‘’;
position: absolute;
top: 0px;
right: 0px;
display:block;
width: 0;
height: 0;
border: 10px solid transparent;
border-bottom-color: white;

第二种

.div>p::after{
content: ‘’;
position: absolute;
top: 28px;
right: 26px;
width:5px;
height: 5px;

border-bottom: 1px solid black;
border-right: 1px solid black;
transform: rotate(45deg);
}