Previously, when a percentage value was used for the
text-indent CSS property, it was resolved against the content width of the containing block’s parent element. It means the following
p element would have
50px of indent, not
<div style="width: 500px;"> <p style="width: 200px; text-indent: 10%;"> Hello World! </p> </div>
This weird behaviour has been solved in the latest CSS spec. Firefox 65 has made the change along with Chrome 72, so the value will be resolved against the width of the containing block itself from now on. You may want to double check your stylesheets as indents could be shorter than before in some cases like the example above, which will be
20px as expected. In fact, the BBC homepage is known to be affected.