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

html,
body {
    width: 100%;
    height: 100%;
    overflow: hidden;
}

body {
    background-image: url('./images/pc_s8.jpg');
    background-size: 100% 100%;
    background-repeat: no-repeat;
    background-size: 100% auto;
    background-position: center;
}

@media (max-width: 768px) {
    body {
        background-image: url('./images/mobile_s8.jpg');
          background-size: 100% 100%;
    }
}