<div id="wrap">

  <!-- section -->
  <div class="section">
    <div class="center">

      <div class="block block--1"></div>
      <div class="block block--2"></div>

    </div>
  </div>
  <!--/section -->

</div>

html,
body {
  margin: 0;
  padding: 0;
  font-family: sans-serif;
  font-size: 16px;
  line-height: 1.4;
  color: #555;
  background: #fff;
}

* {
  box-sizing: border-box;
}

#wrap {
  position: relative;
}

.section {
  padding: 40px;
}

.center {
  width: 100%;
  max-width: 980px;
  margin: auto;
}

.block {
  display: inline-block;
  width: 100px;
  height: 100px;
  margin: 10px;

  &::before {
    content: '';
    display: block;
    width: 100%;
    height: 100%;
    background: #000;
    transition: all 2s cubic-bezier(0.5, -0.5, 0.5, 1.5);
  }

  &--1 {
    &:hover {
      &::before {
        opacity: .2;
      }
    }
  }

  &--2 {
    &:hover {
      &::before {
        transform: scale(.2);
      }
    }
  }
}