* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    width: 100vw;
    height: 100vh;
    background-image: url('../img/download/bg.png');
    background-size: 100% 100%;
    background-repeat: no-repeat;
    position: relative;
}
.back {
    position: absolute;
    top: 20px;
    left: 20px;
    width: 15px;
    height: 15px;
    border-bottom: 2px solid #FFFFFF;
    border-left: 2px solid #FFFFFF;
    transform: rotate(45deg);
    /* background-image: url('../img/download/back.png');
    background-size: 100% 100%;
    background-repeat: no-repeat;
    cursor: pointer; */
}
.btn {
    position: absolute;
    bottom: 100px;
    left: 50%;
    transform: translate(-50%, -50%);
}
img {
    width: 170px;
    height: 58px;
    display: block;
}
img.btn2 {
    margin-top: 20px;
}