How the intermediate steps in a CSS animation sequence can be controlled?

The @keyframes CSS at-rule controls the intermediate steps in a CSS animation sequence by defining styles for keyframes (or waypoints) along the animation sequence. This gives more control over the intermediate steps of the animation sequence than transitions.

@keyframes identifier {
  0% { top: 0; left: 0; }
  30% { top: 50px; }
  68%, 72% { left: 50px; }
  100% { top: 100px; left: 100%; }
}

Source: https://developer.mozilla.org/en-US/docs/Web/CSS/@keyframes