HTML - The bones of the site.
It's the image you see on the left.
It's the buttons you see at the bottom.
It's the text that you can currently read.
It's the line break in the middle of a paragraph...
that is too long to fit in one line.
CSS - the muscles of the site.
It's what rounds the corners.
It's what regulates the images' size.
It's what makes the margins between elements.
It's what enlarges the buttons, when you hover over them.
It's what decides, if overflowing text should wrap to the next line, or be hidden.
JS - The brains of the site.
It's what powers the buttons and circles,
changing the slide when one is tapped.
It's what changes the backgound...
and (paired with CSS) enlarges and colors a circle...
based on what slide you're currently on.
