body{
    margin:0;
    margin-top:50px;
}
header{
    display:flex;
    position:fixed;
    top:0;
    left:0;
    right:0;
    height:50px;
    line-height:50px;
    background-color:black;
}
header *{
    display:inline;
}
header li{
    margin-left:20px;
}
header a{
    text-decoration:none;
    color:white;
}
section{
    height:100vh;
    border:1 px solid black;
    display:flex;
    justify-content:center;
    text-align:center;
    background-repeat:no-repeat;
    background-position:center;
    background-size:cover;         
    place-items:center;                                                                                                                                                                                                                                                                                    

}
#about li{
    list-style-type:none;
}
footer{
    text-align:center;
    padding:40px;
}

#home{
    background-image:linear-gradient(rgba(255,255,255,0.2),rgba(255,255,255,0.2)),url('mobile1.avif');
}
#about{
    background-image:linear-gradient(rgba(255,255,255,0.2),rgba(255,255,255,0.2)),url('m2.jpeg');
}
#contact{
    background-image:linear-gradient(rgba(255,255,255,0.2),rgba(255,255,255,0.2)),url('mobile2.avif');
}