h1 {
   background: red; 
   min-height: 2em;
}
h1 strong {
    transition: all 250ms 200ms;
    display: block;
}
h1 span {
    display: block;
    font-weight: normal;
    font-size: .75em;
    text-wrap: balance;
    position: absolute;
    transition: all 250ms 250ms;
    white-space: nowrap;
}
#machin {
    display: none;
}
#machin:target {
    display: block;
}
h1 span:not(.default),
h1 span.hidden{
    opacity: 0;
}
h1 span.visible{
    opacity: 1;
    transition-delay: 300ms;
    transition-duration: 500ms;
}

h1.wtf  strong { font-size: .65em;}
h1.wtf  span { font-size: 1.15em;}