style.css

.responsive-image{
    width: 100%;
    background-size: 100% 100%;
    background-color: lightblue;
}

.summary {
  list-style-type: none;
  position: absolute;
  color: white;
  font-size: 24px;
  font-weight: bold;
  top: 50%;
  left: 50%;
  margin-right: -50%;
  transform: translate(-50%, -50%)
} 

.transbox {
  background: transparent;
  color: white;
}


/*and finally, we serve for every view-port the right image:*/

/* Retina display */
@media screen and (min-width: 1024px){
    .responsive-image{
        background-image: url('./images/background/1366.png');
    }
    .summary {
      font-size: 30px;
    }
    .transbox {
      font-size: 30px;
    }
}

/* Desktop */
@media screen and (min-width: 980px) and (max-width: 1024px){
    .responsive-image{
        background-image: url('./images/background/1024.png');
    }
    .summary {
      font-size: 22px;
    }
    .transbox {
      font-size: 22px;
    }
}

/* Tablet */
@media screen and (min-width: 760px) and (max-width: 980px){
    .responsive-image{
        background-image: url('./images/background/980.png');
    }
    .summary {
      font-size: 14px;
    }
    .transbox {
      font-size: 14px;
    }
}

/* Mobile HD */
@media screen and (min-width: 350px) and (max-width: 760px){
    .responsive-image{
        background-image: url('./images/background/760.png');
    }
    .summary {
      font-size: 10px;
    }
    .transbox {
      font-size: 10px;
    }
}

/* Mobile LD */
@media screen and (max-width: 350px){
    .responsive-image{
        background-image: url('./images/background/350.png');
    }
    .summary {
      font-size: 8px;
    }
    .transbox {
      font-size: 8px;
    }
}