How to set fixed sidebar width?

Question

css

Good afternoon. Making a fixed column on flexbox

.wrapper
 .sidebar
   li anchor
   li anchor
   li anchor
 .main

and correspondingly

.wrapper {
  height:100vh;
  display:flex;
}
.sidebar {
   flex: 1 0 200px;
    background: gray;
}
.main {
    flex: 1 1 auto;
  padding: 20px;
  overflow: auto;
}

But the sidebar is half the screen wide. Why?
code pen

Answer 1

flex-grow seems to be the block ratio