body, html {
    margin: 0;
    padding: 0;
    height: 100%;
    background-color: #fff;
}

.bg {
    width: 100%;
    height: auto;
    display: block;
}

.button {
    position: absolute;
    width: 50px;
    height: 30px;
    background: rgba(255,255,255,0.01); /* прозрачная */
    display: block;
}