为什么响应式都不出效果，求大神指点
figure{
width:33.33%;
height:257px;
float:left;
overflow:hidden;
position:relative;
}
figcaption{
color:#fff;
top:0; left:0;
position:absolute;
font-family:"微软雅黑";
}
@media screen and(max-width:600px){
figure{width:100%}
}
@media screen and(min-width:601px) and(max-width:1000px){
figure{width:50%}
}
@media screen and(min-width:1001px){
figure{width:33.33%}
}
