Help debugging this HTML please

Hey!

I'm still pretty new to Twine and teaching myself basic HTML and CSS. Wondering why this piece of code isn't working? Have tried debugging myself to no avail.

<div class="fade-in four"><i><span class="zuberitext">"Character A speech"</span></i></div>
<div class="fade-in five"><b>"Character B speech"</b></div>
<div class="fade-in six"><i><span class="zuberitext">Character A speech
<div class="fade-in seven">More of the same speech from Character A
<div class="fade-in eight">End of the same speech from Character A" </span></i></div>

<div class="fade-in nine">Do you [[choice|passage]]? Or do you think [[choice|passage]]?</div>

I removed the particulars of the story just to give an idea of the passage shape. The classes I have are a timed fade in for text and particular colour for Character A's speech.

Any ideas greatly appreciated, cheers!