Not difficult, but depending on what you have to start with it could be a bit tedious. There are probably many ways to code it, but this should give you an idea. Like some verse, you may have to have each line as its own paragraph with its specific style class, and if there are lines long enough to spill over (depending on how you're reading it, display size, and so on) you would have to figure out how to handle that.
The title line, "triangle" might have CSS code for its class like this: (name the classes whatever you like)
Code:
font-size: 2em;
font-weight: bold;
text-align: left;
text-indent: 0;
margin-top: 0;
margin-right:0;
margin-bottom: 2em;
margin-left: 0;
Then each indented line like "Scientists say..." would be something like:
Code:
font-size: 1em;
text-align: left;
text-indent: 0;
margin-top: 0;
margin-right:0;
margin-bottom: 0;
margin-left: 3em;
And each line like "I say" would be:
Code:
font-size: 1em;
text-align: left;
text-indent: 0;
margin-top: 1.5em;
margin-right:0;
margin-bottom: .5em
margin-left: 0;
I'm just guessing at the actual margin values from your example, you can play with them, but this should give a reasonable approximation.