.barra-gris-menu { background-color: #666; padding: 10px 20px;  }
.banner-principal { min-height: 350px; background-color: #ccc; background-size: cover; background-position: center center; position: relative;  }

.articulo-home { margin-top: 6rem;    margin-bottom: 9rem;
    position: relative; }
.imagen-articulo { background-color: #ccc; min-height: 400px;  }
.box-texto { text-align: center;    max-width: 900px;
    background: #f3f3f3;
     padding: 50px 120px;     position: absolute;
    bottom: -100px;
    right: 0;
    left: 0;
    margin: auto; } 
    .box-texto p { margin-top: 30px; margin-bottom: 30px; }