@import url('https://fonts.googleapis.com/css?family=Muli&display=swap');

* {
    margin: 0;
    padding: 0;
}

body {
  font-family: 'Muli', sans-serif;
  display: flex;
  align-items: center;
  justify-content: center;
  height: 100vh;
}

.container {
    width: 90vw;
    display: flex;
}

.panel {
    background-size: cover;
    background-position: center;
    background-repeat: no-repeat;
    height: 80vh;
    color: #fff;
    border-radius: 50px;
    cursor: pointer;
    flex: 0.5;
    margin: 10px;
    position: relative;
    transition: all 700ms ease-in-out;
}

.panel h3 {
    font-size: 24px;
    position: absolute;
    bottom: 30px;
    left: 30px;
    opacity: 0;
}

.panel.active {
    flex: 5;
}

.panel.active h3 {
    opacity: 1;
    transition: all 700ms ease-in-out;
}

@media (max-width: 750px) {
    .container{
        /* display already flex */
        flex-direction: column;
        height: 90vh;
    }
}