discourse/app/assets/stylesheets/common/post-action-feedback.scss

@keyframes draw {
  to {
    stroke-dashoffset: 0;
  }
}

.post-controls {
  .post-action-feedback-button {
    position: relative;
    height: 100%;

    &.is-copied,
    &.is-copied:hover {
      .d-icon-d-post-share {
        color: var(--success);
      }
    }
  }
  .post-action-feedback-svg {
    position: absolute;
    bottom: 0;
    right: 0;
    width: 20px;
    height: 20px;
    display: block;
    stroke: var(--success);
    opacity: 0;
    transition: opacity 0.5s ease-in-out;

    &.is-visible {
      opacity: 1;
    }

    path {
      stroke: var(--success);
      stroke-width: 4;
      stroke-dasharray: 100;
      stroke-dashoffset: 100;
      animation: draw 1s forwards;
    }
  }
}