html – Overflow problem in flexbox

Markup & Styling

  <div id="app">
      <div class="box-1">That is 1</div>
      <div class="box-2">
        That is 2
        <div class="overflow-container">
          <div class="overflow-content">That is my overflow content material</div>
        </div>
      </div>
    </div>

* {
  box-sizing: border-box;
}
physique {
  font-family: sans-serif;
  background: #dedede;
  padding: 48px;
}

#app {
  show: flex;
  width: 100%;
}
.box-1 {
  border: 1px stable purple;
}
.box-2 {
  padding: 10px;
  border: 1px stable blue;
  flex: 1;
}
.overflow-container {
  padding: 10px;
  width: 100%;
  border: 1px stable inexperienced;
  overflow: auto;
}

.overflow-content {
  width: 100%;
  min-width: 2000px;
  border: 1px stable pink;
}

When utilizing the show: flex property, the overflow: auto property would not perform as anticipated. As an alternative, the scale of the father or mother component expands to accommodate the width of the overflowing content material. I am searching for an answer to implement a horizontal scrollbar for the expanded content material.
It does work as anticipated with out flexbox