.columnas {
     -webkit-column-count: 4;
     -webkit-column-gap: 15px;
     -moz-column-count: 4;
     -moz-column-gap: 15px;
     column-count: 5;
     column-gap: 15px;
     column-fill: balance;
 }

 .unidad {
     -webkit-column-break-inside: avoid;
     page-break-inside: avoid;
     /* Firefox */
     break-inside: avoid;
     /* IE 10+ */
     border: 2px solid #FFFFFF;
     display: inline-block;
     margin: 0 5px 20px;
 }

 /* 
  ##Device = Desktops
  ##Screen = 1281px to higher resolution desktops
*/

 @media (min-width: 1281px) {
     .columnas {
         -moz-column-count: 3;
         -webkit-column-count: 3;
         column-count: 3;
     }
 }

 /* 
    ##Device = Laptops, Desktops
    ##Screen = B/w 1025px to 1280px
  */

 @media (min-width: 1025px) and (max-width: 1280px) {
     .columnas {
         -moz-column-count: 3;
         -webkit-column-count: 3;
         column-count: 3;
     }
 }

 /* 
    ##Device = Tablets, Ipads (portrait)
    ##Screen = B/w 768px to 1024px
  */

 @media (min-width: 768px) and (max-width: 1024px) {
     .columnas {
         -moz-column-count: 3;
         -webkit-column-count: 3;
         column-count: 3;
     }
 }

 /* 
    ##Device = Tablets, Ipads (landscape)
    ##Screen = B/w 768px to 1024px
  */

 @media (min-width: 768px) and (max-width: 1024px) and (orientation: landscape) {
     .columnas {
         -moz-column-count: 3;
         -webkit-column-count: 3;
         column-count: 3;
     }
 }

 /* 
    ##Device = Low Resolution Tablets, Mobiles (Landscape)
    ##Screen = B/w 481px to 767px
  */

 @media (min-width: 481px) and (max-width: 767px) {
     .columnas {
         -moz-column-count: 2;
         -webkit-column-count: 2;
         column-count: 2;
     }
 }

 /* 
    ##Device = Most of the Smartphones Mobiles (Portrait)
    ##Screen = B/w 320px to 479px
  */

 @media (min-width: 320px) and (max-width: 480px) {
     .columnas {
         -moz-column-count: 1;
         -webkit-column-count: 1;
         column-count: 1;
     }
 }
 
  .nuevo {
     position: absolute;
     top: -5px;
     right: 1rem;
     font-size: 10px;
     font-weight: bold;
     background: #dab856;
     color: #fff;
     padding: 2.5px 15px;
     -webkit-border-bottom-right-radius: 5px;
     -webkit-border-bottom-left-radius: 5px;
     -moz-border-radius-bottomright: 5px;
     -moz-border-radius-bottomleft: 5px;
     border-bottom-right-radius: 5px;
     border-bottom-left-radius: 5px;
 }

 .nuevo::after {
     content: "";
     top: 0;
     width: 0;
     height: 0;
     right: -4px;
     position: absolute;
     background-color: transparent;
     border-style: solid;
     border-width: 0 4px 5px 0;
     border-color: #dab856;
     border-right-color: transparent;
 }
 
  .promocion-libro {
    width: 100%;
    height: 696px;
    max-width: 1232px;
    min-width: 976px;
    max-height: 600%;
    top: 50%;
    left: 50%;
    
    background-position: center center;
    background-repeat: no-repeat;
    position: fixed;
    z-index: 9999999;
    height: 600px;
    margin: 0 auto;
 }
 
 .promocion-libro-content {
     display: none;
 }

 .promocion-libro-content.show-libro{
    display: flex;
    background: rgba(35, 35, 35, 0.7);
    justify-content: center;
    align-items: center;
    z-index: 999999999;
    position: fixed;
    width: 100%;
    height: 100%;
    line-height:0;
}
.promocion-libro-img  {
    opacity: 0.95;
    max-width: 95%;
    text-align: center;
}

.promocion-libro-close:hover,
.promocion-libro-close:focus {
  color: white;
  text-decoration: none;
  cursor: pointer;
  -ms-transform: scale(1.5);
  -webkit--transform: scale(1.5);
  -o-transform: scale(1.5);
  transform: scale(1.5);
}

.promocion-libro-close {
    position: relative;
    top: 3rem;
    left: 3rem;
    color: #f1f1f1;
    font-size: 40px;
    font-weight: bold;
    transition: 0.3s;
    float: left;
    z-index: 999999;
    font-size: 4em;
    font-weight: bold;
    cursor: pointer;
}

.promocion-libro-content-progres {
    max-width: 95%;
    margin: 0 auto;
}

.promocion-libro-content-progres .progress {
    height: 10px;
    border-radius: unset;
}

.img-responsive {
    margin: 0 auto;
}