In this example I want to rotate the hammer from its bottom so is there a way to know exactly the right coordinates of a specific point on the element or should I randomly t
If you know you want to rotate from a specific point, ie: the bottom left. You can apply the transform origin using the following keywords;
.hammer-icon { // x-offset y-offset transform-origin: left bottom; }
Further reference: https://developer.mozilla.org/en-US/docs/Web/CSS/transform-origin