How to Add a non-clickable text to top of header

To add a non-clickable text to top of Header Squarespace, you can use this CSS code to Custom CSS box.

header#header:before {
    content: "Add something here";
    display: block;
    text-align: center;
    font-size: 16px;
    margin-top: 10px;
    margin-bottom: 10px;
}

Result: