<main>
  <section>
    <div class="container">
      <div class="container-inner"></div>
      <div class="viewport">
        <div class="horizontal-object">
          <div class="horizontal-card"></div>
          <div class="horizontal-card"></div>
          <div class="horizontal-card"></div>
          <div class="horizontal-card"></div>          
          <div class="horizontal-card"></div>
        </div>
      </div>
    </div>
  </section>
</main>

@keyframes scrolldown {
  from {
    transform: translateY(0px);
  }
  
  to {
    transform: translateY(-300px);
  }
}

@keyframes horizontalTransform {
  from {
    transform: translateX(0px); 
  }
  
  to {
    transform: translateX(-300px);
  }
}

body {
  overflow: hidden;
}

main {
  height: 100vh;
  overflow: hidden;
}

section {
  overflow-x: hidden;
  position: relative;
  display: flex;
  flex-flow: row nowrap;
  justify-content: center;
  align-items: center;
  width: 100%;
}

.container {
  position: relative;
  width: 300px;
  height: 500px;
  margin-top: 176px;
/*   border: 1px solid green; */

}

.viewport {
  position: absolute;
  top: 0;
  width: 100%;
  height: 200px;
  border: 1px solid blue;
  transition: top 0.5s;
  display: flex;
  flex-flow: column nowrap;
  justify-content: center;
}

.container-inner {
  position: absolute;
  border: 1px solid green;
  width: 100%;
  height: 500px;
      animation: scrolldown 2s ease-in-out;
  animation-direction: alternate;
  animation-iteration-count: infinite;
}

.horizontal-object {
  position: relative;
  width: 200%;
  height: 100px;
  border: 1px solid red;
  animation: horizontalTransform 2s ease-in-out;
  animation-direction: alternate;
  animation-iteration-count: infinite;
  display: flex;
  flex-flow: row nowrap;
  align-items: center;
}


.horizontal-card {
  height: 80%;
  width: 125px;
  background: red;
  margin: 0 16px;
}