<div class="box"></div>

.box {
  height: 200px;
  background: red;
  margin: 10px;
  padding-bottom: 70px;
  /* curved edge at the bottom */
  mask: radial-gradient(60% 70px at bottom,#0000 98%,#000);
  /* rounded edge at the top */
  clip-path: ellipse(80% 100% at bottom);
}