.spoiler1 {
    display: none;
}

.trigger1.close {
    display: none;
}

.trigger1.open:target {
    display: none;
}

.trigger1.open:target + .trigger1.close {
    display: inline;
}

.trigger1.open:target + .trigger1.close + .spoiler1 {    
    display: block;
}