.introduce{
    background: #fff;
}
.introduce::after{
    content: '';
    display: block;
    clear: both;
}
.introduce > img {
    float: left;
    margin-right: 20px;
    width: 30%;
}
.pamphlet {
    width: 100%;
    display: flex;
    flex-wrap: wrap;
    justify-content: space-between;
}
.pamphlet > a {
    display: block;
    width: 21%;
}