How to stretch a block on Flexbox without touching the rest of the fixed ones?

Question

css

Hello!
I have the following markup:

<style>
  .container {
    display: flex;
    justify-content: space-between;
  }

  .fix {
    width: 200px;
  }
</style>

<div class="container">
  <div class="fix"></div>
  <div class="flex"></div>
  <div class="fix"></div>
</div>

How do I make the boxes stretch to the full width of the .container so that my .fix boxes keep their fixed width of 200px? Because now all blocks are stretched automatically (as I understand it, depending on the content), and my fixed width is ignored

Answer 1

.container {
  display: flex;
}

.flex {
  flex: 1;
}

.fix {
  flex: 0 200px;
}

Answer 2

Probably you still need to read at least one article about flexes and specifically about the flex property.
It's enough

.fix {
  width: 200px;
  flex: none;
}