h2 { color:red; } ____________ /* style=0, ID=0, class=0, element=1 */
header h1 {color:blue;} ______ /* style=0, ID=0, class=0, element=2 */
.cabecera h1 {color:yellow;} _ /* style=0, ID=0, class=1, element=1 */
#caja h1 {color:green;} ______ /* style=0, ID=1, class=0, element=1 */