Untitled

<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width">
  <title>JS Bin</title>
<style id="jsbin-css">
*{
  margin:0;
  padding:0;
}
.left{
  width:200px;
  height:100vh;
  background:red;
  float:left;
  /* border:none; */
}
.right{
  width:calc(100%-200px);
  height:100vh;
  background:green;
  /* float:right; */
  /* border:none; */
}
</style>
</head>
<body>
  <div class="left"></div>
  <div class="right"></div>


<script id="jsbin-source-css" type="text/css">*{
  margin:0;
  padding:0;
}
.left{
  width:200px;
  height:100vh;
  background:red;
  float:left;
  /* border:none; */
}
.right{
  width:calc(100%-200px);
  height:100vh;
  background:green;
  /* float:right; */
  /* border:none; */
}</script>
</body>
</html>