<div class="eq-c">
  <span class="sy"><var>A</var>
    <span class="oncapital">&rarr;</span>
  </span> =
  <div class="fraction">
    <span class="fup">
      <span class="fup">&Delta;
        <span class="sy"><var>v</var>        <span class="onsmall">&rarr;</span>
        </span>
      </span>
    </span>
    <span class="bar">/</span>
    <span class="fdn">&Delta; <var>t</var></span>
  </div>
</div>

// Body
body{
  position: absolute;
  top: 50%; left: 50%;
  transform: translate(-50%, -50%);
  font-size: 2rem;
  text-align: center;
}

// Vectors
.sy {
  position: relative;
  text-align: center;
}
.oncapital, .onsmall {
  position: absolute;
  top: -0.8em;
  left: 0px;
  width: 100%;
  font-size: 70%;
  text-align: center;
}
.onsmall {
  top: -0.5em;
}

.fraction {
    display: inline-block;
    vertical-align: middle; 
    margin: 0 0.2em 0.4ex;
    text-align: center;
  & > span {
    display: block;
    padding-top: 0.15em;
  }
  & span{
    &.fdn {
      border-top: thin solid black;
    }
    &.bar {
      display: none;
    }
  }
}