.nav {
 width: auto;
 height: 50px;
 position: fixed;
 top: 1%;
 left:50%;
 transform: translateX(-50%);
 display: flex;
 align-items: center;
 justify-content: space-around;
 transition: opacity .5s;
 background: blue;
 padding: 10px;
 border-radius: 10px;
 border: 3px solid white;
}