I'm trying to make a custom checkbox using blocks
.checkbox-container {
  height: 18px;
  line-height: 18px;
  margin: 0;
  padding: 0;
  display: inline-block;
  cursor: pointer;
  font-size: 14px;
  position: relative;
  vertical-align: middle;
}
.label {
  margin-left: 4px;
}
.input-box {
  display: inline-block;
  height: 18px;
  width: 18px;
}
.off {
  background-color: #fff;
  border: 2px solid red;
}
.on {
  background-color: red;
  border: 2px solid transparent;
}
.on::after {
  content: '';
  position: absolute;
  left: 6px;
  top: 2px;
  width: 7px;
  height: 11px;
  border: solid #fff;
  border-width: 0 3px 3px 0;
  -webkit-transform: rotate(45deg);
  -ms-transform: rotate(45deg);
  transform: rotate(45deg);
}<div class="checkbox-container">
  <span class="input-box on"></span>
  <span class="label">Checkbox</span>
</div>How can I center the text vertically in this block?
 
     
    