如何将CSS边框颜色应用于椭圆的左侧？

.ellipse {
  width: 200px;
  height: 100px;
  border-radius: 50%;
}

.ellipse::before {
  content: "";
  position: absolute;
  top: 0;
  left: -10px; /* 调整此值以控制边框的宽度 */
  width: 10px; /* 边框的宽度 */
  height: 100%;
  background-color: red; /* 边框的颜色 */
}

.ellipse::before {
  /* ... */
  transform: rotate(-45deg);
  background-color: red; /* 边框的颜色 */
}

.ellipse {
  width: 200px;
  height: 100px;
  border-radius: 50%;
  position: relative;
}

.ellipse::before {
  content: "";
  position: absolute;
  top: 0;
  left: -10px; /* 调整此值以控制边框的宽度 */
  width: 10px; /* 边框的宽度 */
  height: 100%;
  transform: rotate(-45deg);
  background-color: red; /* 边框的颜色 */
}