message: update the threshold value.
diff: let options = {
  root: null,
  rootMargin: "0px",
  - threshold: 1,
  + threshold: [0.7],
  };
  let observer = new IntersectionObserver(beTouching, options);
  }
  }
  + span {
  + transition: all 0.2s;
  + }
  +
  :global(.strikethrough) {
  display: inline-block;
  position: relative;
  