Как расширить меню в две стороны?

setTimeout(() => { 
    document.getElementById("mySidenav").style.left = "0px"; 
  document.getElementById("mySidenav").style.right = "0px"; 
}, 2000);

.container{
  position: relative;
  width: 400px;
  height: 200px;
  background: #ffdddf;
  z-index: 1;
}
.wrapper {
  position: absolute;
  top: 10px;
  left: 100px;
  right: 100px;
  height: 25px;
  background: #000;
  z-index: 2;
  transition: 1s linear;
}

<div class="container" >
  <div class="wrapper" id="mySidenav">
    
  </div>
</div>

setTimeout(() => { 
    document.getElementById("mySidenav").style.width = "90%"; 
}, 2000);

.container{
  display: flex;
  justify-content: center;
  width: 100%;
  background: #ddffdd;
  padding: 10px 0;
}
.wrapper {
  width: 50%;
  height: 50px;
  background: #ddccdd;
  transition: 1s linear;
}

<div class="container" >
  <div class="wrapper" id="mySidenav">
    
  </div>
</div>