.box {
    width: 90%;
    margin-top: 20px;
    text-align: center;
    margin: auto;
}
.box .top {
    height: 100px;
    line-height: 100px;
    font-size: 25px;
    font-weight: 700;
}
.box .bottom_img {
    width: 100%;
}
.box .bottom_img img {
    width: 100%;
}

body {
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}
footer {
    margin-top: auto;
}