Animated Button | Learning Axis

HTML

CSS

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}
body {
  height: 100dvh;
  background: #121212;
  display: grid;
  place-items: center;
}
button {
  appearance: none;
  background: transparent;
  border: none;
  cursor: pointer;
  isolation: isolate;
}
.button {
  background: #efefef;
  font-size: 16px;
  line-height: 1.5;
  font-weight: 500;
  width: 240px;
  border-radius: 9999rem;
  position: relative;
  display: flex;
  justify-content: center;
  align-items: center;
  position: relative;
  isolation: isolate;
  overflow: hidden;
  &>span.text {
    color: #121212;
    width: 100%;
    text-align: left;
    padding-block: 12px;
    padding-left: 24px;
    z-index: 2;
    transition: all 200ms ease;
  }
  &>div.overlay {
    background: #242424;
    color: #ededed;
    width: 48px;
    height: calc(100% - 2px);
    display: flex;
    justify-content: flex-end;
    align-items: center;
    padding: 12px;
    border-radius: inherit;
    position: absolute;
    right: 1px;
    z-index: 1;
    transition: all 400ms ease;
  }
  &:is(:hover, :focus) {
    &>span.text {
      color: #ededed;
    }
    &>div.overlay {
      width: calc(100% - 2px);
      transition: width 200ms ease;
    }
  }
}