Check out example codes for "font size css". It will help you in understanding the concepts better.

Code Example 1

.class {
	font-size: 12px;
}

Code Example 2

p {
	font-size: 150% /*px, cm, in, etc.*/; 
}

Code Example 3

#selector{
    font-size:20px;
}

Code Example 4

<span style="font-size:20px;"></span>

Code Example 5

// to scale font size in relation to its parent element
style="font-size: 2vw;"

Code Example 6

<body>      
         <h1 style="color:red;font-size:40px;">Heading</h1>      
         <p style="color:blue;font-size:18px;">This is demo text</p>    
      </body>

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