*{box-sizing: border-box;}

body{
    margin: 0;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    overflow: hidden;    
}

.container{
    display: flex;    
    width: 80vw;
}

.panel{
   background-size: cover;
   background-repeat: no-repeat;
   background-position:center ;
   height: 80vh;
  border-radius: 50px;
  flex: 0.5;
  position: relative;
  transition: flex 0.8s ease-in;
  cursor: pointer;
color: white;
margin: 10px;
}
.panel h3{
    position: absolute;
    bottom: 20px;
    left:20px;
    opacity: 0;
}
.panel.active {
    flex: 5;
}
.panel.active h3{
    opacity: 1;
    font-size: 25px;
    transition: 0.4s ease-in 0.4s;
    /*  first is for speed ; last is for delay */
}
@media(max-width:480px){
    .container{
        width: 100vw;
    }
    .panel:nth-of-type(4), .panel:nth-of-type(5){
        display: none;
    }
}