Nav bar / Best practices

Hello,

Would you mind taking a look at my code (HTML/CSS) and letting me know what I could be doing better? In addition, my nav bar doesn’t resize correctly to screens but prefacing that, I don’t think I created the nav bar in the best way possible. Thanks in advance for your help.

Here is my nav bar code:
#header {
display: flex;
background-color: rgb(8, 210, 8);
position: sticky;
top: 0;
}
.nav-pos {
display: inline;
margin-left: 80px;
position: relative;
left: 1800px;
top: 130px;
}
#email-title {
text-align: center;
}

Here is the link to my pen: