overflow: scroll on div with flex: 1 without specific height

Question

I have a flexbox layout kinda like Discord. My list is the messageList with all messages I have. I want to add overflow-y: scroll to it but it doesn't work because I don't have a specific height. Also, I don't want to add a specific height because it should be dynamic.

My solution would be.

max-height: calc(100vh - header.height - send.height)

but it only works if you have specific heights for header and send tho.

is there any other way?

example: https://jsfiddle.net/AvaPLaIN/b7umpgzn/44/

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

.container {
  height: 100vh;
  width: 100vw;
  display: flex;
  flex-direction: column;
  border: 2px solid black;
}

.header {
  width: 100%;
  border: 2px solid red;
  min-height: 3rem;
}

.content {
  flex: 1;
  display: flex;
  border: 2px solid green;
}

.chatbox {
  flex: 1;
  border: 2px solid yellow;
  display: flex;
  flex-direction: column;
}

.members {
  width: 15rem;
  border: 2px solid blue;
}

.list {
  flex: 1;
  border: 2px solid grey;
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 0.5rem;
  overflow-y: scroll;
}

li {
  width: 100%;
  border: 1px solid black;
}

.send {
  height: 5rem;
  border: 2px solid purple;
}

<div class="container">
  <div class="header">
    Header here
  </div>
  <div class="content">
    <div class="chatbox">
      <ul class="list">
        <li>1</li>
        <li>2</li>
        <li>3</li>
        <li>4</li>
        <li>5</li>
        <li>6</li>
        <li>7</li>
        <li>8</li>
        <li>9</li>
        <li>10</li>
      </ul>
      <div class="send">
        Send Message here
      </div>
    </div>
    <div class="members">
      Memberlist here
    </div>
  </div>
</div>

Answer 1

Just use flex: 1 1 0 instead of flex: 1 in .list.

The problem is related to flex-basis property and flex: 1 shorthand.

flex-basis: 0px and flex-basis: 0% have different results in some cases. Here is an answer to explain the problem: https://stackoverflow.com/a/63475286/15924950

Also, I made a simple demo to show how difference between flex-basis: 0px and flex-basis: 0%: https://codepen.io/shadow-mike/pen/NWpNVvv