html – Centrar input en web con css

/*Inputsection*/

.box {
  position: absolute;
  top: 50%;
  left: 50%;
  width: 100px;
  transform: translate(-50%, -50%);
  height: 600px;
}

input {
  position: relative;
  display: inline-block;
  font-size: 20px;
  box-sizing: border-box;
  transition: 0.5s;
}

input(type="text") {
  background: chocolate;
  width: 340px;
  height: 50px;
  border: none;
  outline: none;
  padding: 0 25px;
  border-radius: 25px 0 0 25px;
}

input(type="submit") {
  position: relative;
  border-radius: 0 25px 25px 0;
  width: 140px;
  height: 50px;
  border: none;
  outline: none;
  cursor: pointer;
  background: #543;
  color: #fff;
}

input(type="submit"):hover {
  background: #fff;
}
<!--InputSection-->
<section>
  <div class="box">
    <form>
      <input type="text" name="" placeholder="Username">
      <input type="submit" name="" value="Ver">
    </form>

  </div>
</section>