Answers for "make font size fit div"

adjust font size according container width

/**
 * You can automatically increase or decrease 
 * the font size of the text in an element using CSS
 */
<p> Some text to automatically Adjust</p>

<style>

p {
  font-size: 16px; /* The font size if container is too small */
  font-size: 5vw; /* Font size adjustment in percent, if the container is larger and there is more room */
}

</style>

css text to fit container

//The viewport-percentage lengths are relative to the size of the initial
//containing block. When the height or width of the initial containing block
//are changed, they are scaled accordingly.
//vw = (% of the viewport width). So using it will look like this:
p {
    font-size: 2.5vw;
}