<div>裁剪后的背景</div>

div {
  corner-shape: notch;
  border-top-left-radius: 30px 50%;
  border-bottom-left-radius: 30px 50%;
}

/* Ignore */
div {
  width: fit-content;
  border: 1px solid red;
  font: 900 3rem system-ui;
}