Adjust height of a div absolutely positioned according to content

I have a div with position: absolute, and many more divs inside of it. I'm trying to adjust this div's height to the content it has inside, but its height is not increasing. What can I do to adjust its height automatically according to its content?

My HTML:

body
div(id="contentAcerca")
  div(id="imagenEquipo")
    div(id="descripcionPlataforma")
        p(id="tituloPlataforma") PERSPECTIVA A4
        p(id="textoPlataforma") Lorem Ipsum is simply dummy text of the printing and typesetting industry.

CSS:

#contentAcerca {                
z-index: -1;
position: absolute;
left: 7.5%;
top: 25%;
min-height: 65%;
width: 85%;
background: white;
border-radius: 3px;
border: 0;
outline: 0;
-webkit-box-shadow: 0 0 10px #aeaeae;
-moz-box-shadow: 0 0 10px #aeaeae;
box-shadow: 0 0 10px #aeaeae;
}

#imagenEquipo {
position: absolute;
top: 5%;
width: 95%;
height: 100%;
background-image: url("../images/acerca/equipo.jpg");
background-size: cover;
background-repeat: no-repeat;
left: 2.5%;
}

#descripcionPlataforma {
    position: absolute;
    width: 100%;
    background-color: #808080;
    border-radius: 5px;
    top: 100%;
}

#tituloPlataforma {
    position: relative;
    left: 2.5%;
    color: rgba(235, 81, 77, 1);
    font-size: 2vw;
}

#textoPlataforma {
    position: relative;
    left: 2.5%;
    color: white;
}

And finally this is what I'm getting:

But this is what I need:

As you can see, the containing div (the one with the white background) is bigger, because of the image and the div with gray background.

Many Thanks in advance!