body {
    font-family: Verdana, Geneva, Tahoma, sans-serif;
    font-size: 18px;
}

nav {
    box-sizing: border-box;
    height: 100%;
    width: 203px;
    position: fixed;
    top: 0;
    left: 0;
    background-color: gray;
    padding: 0px 20px;
}
nav ul {
    list-style: none;
    padding: 0;
}
nav a{
    text-decoration: none;
    color: white;
    display: block;
    padding: 12px 4px;
}
nav a:hover {
    transition: 0.5s;
    color: yellow;
}

main {
    margin-left: 200px;
}

.image {
    border-radius: 8px;
    box-shadow: 4px 4px 8px gray;
}
.image:hover {
    box-shadow: 4px 4px 8px rgb(100, 100, 100);
}

.w-450 {
    width: 450px;
}
@media screen and (max-width: 768px){
    .w-450 {
        width: 100%;
    }
}

@media screen and (max-width: 480px){
   nav {
    width: 100%;
    height: 200px;
    padding: 10px 12px;
   }
   main {
    margin-left: 0;
    margin-top: 200px;
   }
   nav ul {
    margin: 0;
   }
   nav li, nav a {
    display: inline-block;
   }
}