How to create a completely flexible piano keyboard with HTML and CSS

Question

I\'m trying to create a piano keyboard that will keep it\'s elements ratios using flex box, but can\'t seem to make the black notes stay the same width or height once I star

Answer 1

Not sure if you need your black keys to be independent blocks but here is an example

body {
  background: #000;
}

.note-container {
  width: 100%;
  display: flex;
  flex-flow: row nowrap;
}

.white-note {
  position: relative;
  width: 10%;
  height: 400px;
  background: #fff;
  margin: 0 2px;
}

.white-note.black-note:after {
  content: "";
  position: absolute;
  top: 0;
  right: -25%;
  width: 50%;
  height: 50%;
  background: #000;
  z-index: 1;
}