Make the header bar fixed

Make the navigation bar in the <header> section dynamically fixed so when you scroll down you still have the menu at hand and can easily check your remaining points. For better results, it could be dynamically switched to fixed only when you are a couple of lines down so it will still keeps in its place when you are at the top. For this to work, you may need to play with z-index.

Example:

header {
    background-image: linear-gradient(#515763 0%, #2f3540 100%);
    padding: 5px 0;
    position: fixed;
    width: 100%;
    z-index: 1;
}