how to change another element on hover
// If the cube is directly inside the container: #container:hover > #cube { background-color: yellow; } // If cube is next to (after containers closing tag) the container: #container:hover + #cube { background-color: yellow; } // If the cube is somewhere inside the container: #container:hover #cube { background-color: yellow; } // If the cube is a sibling of the container: #container:hover ~ #cube { background-color: yellow; }