Check out example codes for "how to call an id in css". It will help you in understanding the concepts better.

Code Example 1

/*put a # infront of the id*/
/*<section id="example"></section>*/
#example{
	margin: auto;
}

Code Example 2

<style>
  #selector {
  color: red;
}
/* # is id selector */
</style>


<div id="selector">
<p>This is an id</p>
</div>

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