<div class="panels">
  <div class="panel panel1">
    <p>Hey</p>
    <p>Let's</p>
    <p>Dance</p>
  </div>
  <div class="panel panel2">
    <p>Give</p>
    <p>Take</p>
    <p>Receive</p>
  </div>
  <div class="panel panel3">
    <p>Experience</p>
    <p>It</p>
    <p>Today</p>
  </div>
  <div class="panel panel4">
    <p>Give</p>
    <p>All</p>
    <p>You can</p>
  </div>
  <div class="panel panel5">
    <p>Life</p>
    <p>In</p>
    <p>Motion</p>
  </div>
</div>

html {
  box-sizing: border-box;
  background: #ffc600;
  font-family: 'helvetica neue';
  font-size: 20px;
  font-weight: 200;
}

body {
  margin: 0;
}

*,
*:before,
*:after {
  box-sizing: inherit;
}

.panels {
  min-height: 100vh;
  overflow: hidden;
  display: flex;
  
  .panel {
    background: #6B0F9C;
    box-shadow: inset 0 0 0 5px rgba(255, 255, 255, 0.1);
    color: white;
    text-align: center;
    align-items: center;
    transition: 
      font-size 0.7s cubic-bezier(0.61, -0.19, 0.7, -0.11),
      flex 0.7s cubic-bezier(0.61, -0.19, 0.7, -0.11),
      background 0.2s;
    font-size: 20px;
    background-size: cover;
    background-position: center;
    flex: 1;
    justify-content: center;
    align-items: center;
    display: flex;
    flex-direction: column;
    cursor: pointer;
    
    &.panel1 {
      background-image: url(https://source.unsplash.com/gYl-UtwNg_I/1500x1500);
    }

    &.panel2 {
      background-image: url(https://static.pexels.com/photos/544115/pexels-photo-544115.jpeg);
    }

    &.panel3 {
      background-image: url(https://images.unsplash.com/photo-1465188162913-8fb5709d6d57?ixlib=rb-0.3.5&q=80&fm=jpg&crop=faces&cs=tinysrgb&w=1500&h=1500&fit=crop&s=967e8a713a4e395260793fc8c802901d);
    }

    &.panel4 {
      background-image: url(https://source.unsplash.com/ITjiVXcwVng/1500x1500);
    }

    &.panel5 {
      background-image: url(https://source.unsplash.com/3MNzGlQM7qs/1500x1500);
    }
    
    > * {
      margin: 0;
      width: 100%;
      transition: transform 0.5s;
      flex: 1 0 auto;
      display: flex;
      justify-content: center;
      align-items: center;
      
      &:first-child {
        transform: translateY(-100%);
      }
      
      &:last-child {
        transform: translateY(100%);
      }
    }
    
    &.open-active > *:first-child {
      transform: translateY(0);
    }
    
    &.open-active > *:last-child {
      transform: translateY(0);
    }
    
    &.open {
      font-size: 40px;
      flex: 5;
    }
    
    p {
      text-transform: uppercase;
      font-family: 'Amatic SC', cursive;
      text-shadow: 0 0 4px rgba(0, 0, 0, 0.72), 0 0 14px rgba(0, 0, 0, 0.45);
      font-size: 2em;
      
      &:nth-child(2) {
        font-size: 4em;
      }
    }
  }
}

.cta {
  color: white;
  text-decoration: none;
}

const panels = document.querySelectorAll('.panel');
function toggleOpen() {
  this.classList.toggle('open');
}
function toggleActive(e) {
  if (e.propertyName.includes('flex')) {
    this.classList.toggle('open-active');
  }
}
panels.forEach(panel => panel.addEventListener('click',toggleOpen));
panels.forEach(panel => panel.addEventListener('transitionend',toggleActive));