.intr_left {
    float: left;
    width: 8rem;
    height: 16rem;
    border-radius: 1.6rem;
    margin-left: 8rem;
    margin-top: 4rem;
    background: url(images/jianjie.jpg) no-repeat center;
    background-size: 100% 100%;
    box-shadow: 0 0 .32rem #ccc;
    transition: 1s;
}
.intr_left:hover {
    background-size: 120% 120%;
}
.jianjie {
    float: left;
    background: url(images/jianjie.jpeg) no-repeat center;
    background-size: 100% 100%;
    width: 20.5rem;
    height: 16rem;
    margin-left: 1.6rem;
    margin-top: 4rem;
    border-radius: 1.6rem;
    box-shadow: 0 0 .32rem #ccc;
    background-color: pink;
    transition: 1s;
}
.jianjie h1 {
    font-size: 1.3333rem;
    font-family: "微软雅黑";
    color: white;
    text-align: center;
}
.jianjie p {
    color: wheat;
    font-size: 1.0133rem;
    color: white;
    text-indent: 2em;
}
.jianjie:hover {
    background-size: 120% 120%;
}