*  {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    font-size: 62.5%;
    line-height: 1;
}

p {
    font-size: 15px;
    font-size: 1.5rem;    
    line-height: 1.333333334;
    margin-bottom: 20px;
    margin-bottom: 2rem;
    text-align: justify;
}

.three-columns {
    
    -webkit-column-count: 3; /* Chrome, Safari, Opera */
    -moz-column-count: 3; /* Firefox */
     column-count: 3;
    
    -webkit-column-gap: 20px; /* Chrome, Safari, Opera */
    -moz-column-gap: 20px; /* Firefox */
     column-gap: 20px;
    
    -webkit-column-gap: 2rem; /* Chrome, Safari, Opera */
    -moz-column-gap: 2rem; /* Firefox */
    column-gap: 2rem; */

}

 .boton_1 
    {  
    text-decoration: none;
    padding: 10px;
    padding-left: 30px;
    padding-right: 30px;
    font-family: "Open Sans", sans-serif;
    font-weight: 300;
    font-size: 20px;
    font-style: inherit;
    color: #ffffff;
    background-color: #2797ef;
    border-radius: 5px; 
  }
    
    

    
.boton_1:hover {
/* background: #088A08;/*rgba(0,0,0,0);*/
/* background: #1bbc9d;/*rgba(0,0,0,0);*/
 background: #084B8A ;/*rgba(0,0,0,0);*/
 color: #ffffff;
/* box-shadow: inset 0 0 0 3px #1bbc9d;*/
}


  #contenido {
        margin:0 auto;
        width:950px;
        /*border:1px solid black;*/
        border: #f2f2f2 
    }
    #contenido_izquierda {
      /*  border:1px solid #f2f2f2;*/
        width:300px;
        float:left;
        height: 100%; /*<----- */
        border-collapse: separate;
        border-spacing: 10px 5px;
        
    }
    #contenido_central {
        /*border:1px solid #f2f2f2;*/
        width:300px;
        float:left;
        height: 100%; /*<----- */
        border-collapse: separate;
        border-spacing: 10px 5px;
    }
    #contenido_derecha {
       /* border:1px solid #f2f2f2;*/
        width:300px;
        float:right;
        height: 100%; /*<----- */
        border-collapse: separate;
        border-spacing: 10px 5px;
    }
    .clear{
        clear:both; /*<----- */
        }
.div {
    margin-right: 10px;
}

.contenedor{
    display:flex;
}
.elemento{
    width:25%;
}