.seccion-oscura{height:100%;}
.seccion-oscura {
position: relative;
}
.seccion-oscura::before {
content: "";
position: absolute;
inset: 0;
background: rgba(0, 0, 0, 0.4);
z-index: 1;
}
.seccion-oscura * {
position: relative;
z-index: 2;
}