Animations in websites can be done in many ways. From coding it in vanilla Javascript, to the countless libraries you can download, to Flash (rip), you can pick and choose what you use to fit your needs. But one basic way to do so is in CSS. This is useful since they are natively supported by all the major browsers and don't require any extra downloads. In this post, we will show how to rotate and scale in multiple dimensions.

Setting the Stage

note: this will be done in SCSS
First, we need to set up the objects we want to animate. We will create 3 axes, and a circle at the center, all as divs. We'll wraps them in a single parent "scene" div. This will be all the HTML we'll need for this. So far, our code is:

<div class='scene'>
  <div class="axis x"></div>
  <div class="axis y"></div>
  <div class="axis z"></div>
  <div class='circle'></div>
</div>

However, if you look at this in the browser, you'll see nothing. So now, we need to add some basic properties to our divs.
For our body, let's set the background-color to black, display to grid, place-items to center, min-height to 100vh (100% of the viewport size), and overflow to hidden.
For our scene div, we just need to set the position to relative.
For our 3 axis divs, we'll give them a height of 1px (1 pixel), a width of 200vh (twice the size of the viewport), a left of -100vh (to center them), and position to absolute. We'll also give each axis their own color, using the x, y, and z classes. We will also rotate y by 90deg around the z-axis, and the z by 90deg around the y axis.
Lastly, we'll give the circle div a position of absolute, border-radius of 50% (which will make it a circle), a width and height of 120px, a left and top of -60px (to center it), and a background of white.
So far, it should look like:

Starting the animations: Rotating the scene

Let's start by animating the entire scene, so it is if we are orbiting the circle. First, we have to set the perspective of the body to 800px, so the "camera" will be 800px from the center. We will also add

  *:not(:empty){
    transform-style: preserve-3d;
  }

to the body which will allow us to see things in 3 dimensions.
Next, let's add an initial rotation around the x-axis by adding transform: rotateX(10deg);.
Since we are rotating the whole scene, we will give the animation to the scene div. Our animation will take 4 inputs: a name, a duration, an iteration number, and a timing function. Let's call this animation "orbit", have it last 20 seconds, repeat infinitely, and with a linear timing function. So far, it should look like animation: orbit 20s infinite linear;
Next, we have to create the keyframes. Each keyframe will specify how far we want the rotation to go. Luckily, we only need two keyframes. The first will be at 0%, where we will give it a transform of rotateY(0). This is the starting position. At 100%, we want it to make a full rotation, so we can set another keyframe at 100%, and give it a transform of rotateY(360deg). We will also have to add the rotateX(10deg) in each transform, in order to keep that constant.
Now, the animation will look like:

Rotating the Circle

Now, let's add an animation to the circle, so it rolls while clicked. First, we have to add the animation to the '.circle' div. Here, we will use animation: roll 5s infinite linear;. We will also use very similar keyframes as the scene, but with rotateX instead of rotateY. If you look at the code now, you'll see that the circle is rotating around the x-axis. However, we only want it to do so while clicked. So in .circle., we will add animation-play-state: paused;. This will set the default state of the circle's animation to not run. Now, we'll add a new section, for .circle:active. This will be applied while the .circle div is being clicked. In here, we will add animation-play-state: running;, making the animation run.
Now, it will be:

Scaling the Circle

Lastly, let's add another animation to the circle.
Firstly, if we just add another animation, it will override the transitions that we already wrote. So let's first wrap our circle div in a new squish div.
Next, we will make it stretch horizontally, then return to normal, then stretch vertically, and then return to normal. Again, we will have to add an animation to .circle. We will add , squish 20s infinite linear to our animation property in .circle. We will also have to add , running to the animation-play-state property, so it will run by default. Now, the keyframes will be more difficult. First, we'll set the keyframes that will be the default values. This will happen at 0%, 50%, and 100%. So we will add a keyframe of 0%, 50%, 100% { transform: scale(1); }. Next, at 25%, we want to have a transform of scaleX(4), which will make it four times as long. Finally, at 75%, we want a transform of scaleX(4) to make it 4 times as tall.
Our final product will be:

Final thoughts

Congrats! This is the first step towards understanding animations in CSS. There are many other operations you can do to make even more complicated animations, and there are some really impressive examples out there. Keep playing around with it make it even cooler!