Please explain id

[evancode2017]

Please explain how I should create an id selector in the CSS file for the id: header-text which is in a div that is nested in another div. Thanks.

[datfatcat]

You use # and then the id name.
eg

<div id="foo">
    <p>hello!</p>
</div>

#foo {
    text-align: center;
}