css - Why can't I see my whole background image on mobile? -

i have question about: why can't se whole background image on mobile, can on desktop?``

this homepage: http://odsgaardklausen.dk/cj/

i don't now, if have make mistake?

    /* generelt */ html {         min-height:100%; }    .frontimage{         background-image: url('img/frontimage.jpg') !important;         background-position: center center;         bottom: 0;         right; 0;         background-repeat: no-repeat;         background-attachment: fixed;         background-size: cover;         background-color: #464646;         z-index: -1;         height: 100vh;         width: 100%; } .about-text{ margin:auto; width:30%; } ul{ list-style-type: none; } #cj{ width:300px; height:300px; margin:auto; } #skills {         width:100%;     background-color: #fffaf5;     padding-top: 48px; } .row {     width:100%;     margin:0;     padding:0; } @media screen , (max-width: 767px){     .about-text{         margin:auto;         width:80%;     } } 

i think because of background-size: "cover". means, background image scale large possible background area covered background image. parts of background image may not in view within background positioning area.