Override element.style using CSS

Although it's often frowned upon, you can technically use:

display: inline !important;

It generally isn't good practice but in some cases might be necessary. What you should do is edit your code so that you aren't applying a style to the <li> elements in the first place.

element.style comes from the markup.

<li style="display: none;">

Just remove the style attribute from the HTML.

This CSS will overwrite even the JavaScript:

#demofour li[style] {
    display: inline !important;
} 

or for only first one

#demofour li[style]:first-child {
    display: inline !important;
}