@import url("https://fonts.googleapis.com/css2?family=roboto&family=lobster&display=swap");
*{
    color:#00f;
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family:"roboto", sans-serif;
    font-size: 1.5 rem;
    min-height: 200vh;

}

.outer-container{
    border:3px dashed #000;
    width:75vw;
    height: 85vh;
    margin: 40px auto;
    position: relative;
}

.inner-container{
    border:2px solid #00f;
    width:40vw;
    height: 50vh;
    margin: 200px auto;
    position: relative;
    
}

.box{
    width: 150px;
    height: 150px;
    color:#fff;
    padding: 1rem;
}

.absolute{
    background-color: #00f;
    position: absolute;
    top: 100px;
    left:50px;
    z-index: 1;
}

.relative{
    background-color: red;
    position: relative;
    top: 100px;
    left: 100px;
}

.fix{
    background-color:green;
    position: fixed;
    top: 200px;

}

.sticky{
    background-color:#000;
    position: sticky;
    top:0;
}

section{
    height: 100vh;
}

.blue{background-color:blue;}
.read{background-color:red;}
.green{background-color:green;}
header,footer{
    color: #fff;
    text-align:center;
    height: 100px;
    font-size: 5rem;
}

header{
    position: sticky;
    top:0;
}
footer{
    background-color:#000;
    position:fixed;
    bottom: 0;
    width: 100%;
    font-size:3rem;

}

a:visitied{
    color:#fff;
}

.social {background-color:royalblue;
color:#fff;
font-size: inherit;
padding: 1rem;
position: fixed;
top: 30%;
left:0;
}

.header img{
    max-width:100%;
    height: auto;
    display: block;
}

.main-header{
    background-image: url('pic.jpg');
    background-size: cover;
    background-position: center;
    height: 400px;

}