I have a left sided menu in the head of my website. Sadly the menu is floating over the other content.

Instead, i want it to take up this part of the website and the rest of the content to be placed next to it, not under it.

I know I could just put the menu and the content into the same container, but I would have to remove the menu from the head.

The menu:

#nav_bar {
    background: #181818;
    width: 60px;
    height: 100%;
    position: fixed;
    top: 0;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    z-index: 3;
    min-height: 500px;
}