how to use id tags in css code example

Example 1: css how to style id

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

Example 2: referance html id css

<style>
  #test {
  /*Styleing here*/
  }
</style>
<h1 id="test"></h1>