* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}
html ´{
    font-size: 62.5%;
}
body {
    display: grid;
    place-items: center;
    height: 100vh;
    font-family: 'Open Sans', sans-serif;
    overflow: hidden;
}
.container {
    display: flex;
    width: 90vw;
}

.panel {
    background-size: cover;
    background-position: center;
    background-repeat: no-repeat;
    height: 80vh;
    border-radius: 40px;
    color: white;
    cursor: pointer;
    flex: 0.5;
    margin: 10px;
    position: relative;
    transition: flex 0.7s ease-in;
}
.panel h3 {
    font-size: 2.4rem;
    position: absolute;
    bottom: 20px;
    left: 20px;
    margin: 0;
    opacity: 0;
}
.panel.active {
    flex: 5;
}
.panel.active h3 {
    opacity: 1;
    transition: opacity 0.5s ease-in 0.5s;
}

@media (max-width: 600px) {
    .container {
        width: 100vw
    }
    .panel:nth-of-type(4), .panel:nth-of-type(5) {
        display: none;
    }
}