Transition multiple properties CSS

You can transition a single property:

.fader {
    transition: opacity 500ms ease;
}

Or all properties:

.fancy {
    transition: all 500ms ease;
}

Or some specific properties:

.mover-and-fader {
    transition: all 500ms ease;
    transition-property: opacity, transform, width, height;
}

See transition-property from the MDN documentation.