Flexbox. Avoid Child With Longer Height Than Parent (column Direction)

I'm scaffolding a basic UI for a site using flexbox. Quite similar to the usual email layout. For some reason the second children( class .main-body, lightseagreen color) of a colum

Solution 1:

Flexbox introduces auto as the new initial value of min-height. It makes flex items grow as tall as their contents.

You can undo that by setting min-height to 0, the old initial value:

.content-main {
  min-height: 0;
}

html,
body {
  width: 100%;
  height: 100%;
  background: lightblue;
  box-sizing: border-box;
}
* {
  box-sizing: border-box;
}
.container {
  height: inherit;
  background: PeachPuff;
  padding: 1em;
  display: flex;
  max-height: 500px;
}
.sidebar {
  flex: 0115%;
  background: khaki;
}
.content {
  flex: 11 auto;
  background: plum;
  padding: 0.8em;
  display: flex;
  flex-direction: column;
}
.content-header {
  background: lightgreen;
  padding: 0.3em;
  flex: 007%;
}
.content-main {
  display: flex;
  background: darkseagreen;
  padding: 1em;
  height: 100%;
  flex: 11 auto;
  min-height: 0;
}
.main-list {
  flex: 0012%;
  background: lightcoral;
}
.main-body {
  flex: 01 auto;
  padding: 1em;
  background: lightcyan;
  display: flex;
  flex-flow: row wrap;
  overflow-y: scroll;
}

<divclass='container'><divclass='sidebar'><ul><li>Onnnne</li><li>Twoo</li><li>Threee</li></ul></div><divclass='content'><divclass='content-header'><span>This iscontent header</span></div><divclass='content-main'><divclass='main-list'><ul><li>List 1</li><li>List 2</li><li>List 3</li></ul></div><divclass='main-body'><divclass='panel'><table><thead><th>First</th><th>Second</th><th>Third</th><th>Third</th><th>Third</th><th>Third</th></thead><tbody><tr><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td></tr><tr><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td></tr><tr><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td></tr><tr><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td></tr><tr><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td></tr><tr><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td></tr><tr><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td></tr></tbody></table></div><divclass='panel'><table><thead><th>First</th><th>Second</th><th>Third</th><th>Third</th><th>Third</th><th>Third</th></thead><tbody><tr><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td></tr><tr><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td></tr><tr><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td></tr><tr><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td></tr><tr><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td></tr><tr><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td></tr><tr><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td></tr></tbody></table></div><divclass='panel'><table><thead><th>First</th><th>Second</th><th>Third</th><th>Third</th><th>Third</th><th>Third</th></thead><tbody><tr><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td></tr><tr><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td></tr><tr><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td></tr><tr><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td></tr><tr><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td></tr><tr><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td></tr><tr><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td></tr></tbody></table></div><divclass='panel'><table><thead><th>First</th><th>Second</th><th>Third</th><th>Third</th><th>Third</th><th>Third</th></thead><tbody><tr><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td></tr><tr><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td></tr><tr><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td></tr><tr><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td></tr><tr><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td></tr><tr><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td></tr><tr><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td></tr></tbody></table></div><divclass='panel'><table><thead><th>First</th><th>Second</th><th>Third</th><th>Third</th><th>Third</th><th>Third</th></thead><tbody><tr><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td></tr><tr><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td></tr><tr><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td></tr><tr><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td></tr><tr><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td></tr><tr><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td></tr><tr><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td></tr></tbody></table></div><divclass='panel'><table><thead><th>First</th><th>Second</th><th>Third</th><th>Third</th><th>Third</th><th>Third</th></thead><tbody><tr><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td></tr><tr><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td></tr><tr><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td></tr><tr><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td></tr><tr><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td></tr><tr><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td></tr><tr><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td><td>1</td></tr></tbody></table></div></div></div></div></div>