Use .pow-width-auto class to set width: auto to an element

Use .pow-width-100 class to set width: 100% to an element

Use .pow-max-width-auto class to set max-width: auto to an element

Use .pow-max-width-100 class to set max-width: 100% to an element

Use .pow-height-auto class to set height: auto to an element

Use .pow-height-100 class to set height: 100% to an element

Use .pow-max-height-auto class to set max-height: auto to an element

Use .pow-max-height-100 class to set max-height: 100% to an element

Use .pow-box-sizing class to set box-sizing: border-box to an element

You can combine all these classes on the same element

<span class=".pow-width-auto"></span>
<span class=".pow-width-100"></span>
<span class=".pow-max-width-auto"></span>
<span class=".pow-max-width-100"></span>
<span class=".pow-height-auto"></span>
<span class=".pow-height-100"></span>
<span class=".pow-max-height-auto"></span>
<span class=".pow-max-height-100"></span>
<span class=".pow-box-sizing"></span>