如何绘制具有圆角半径的三角形？

.triangle {
  width: 0;
  height: 0;
  border-left: 50px solid transparent;
  border-right: 50px solid transparent;
  border-bottom: 100px solid #000;
}

.triangle {
  width: 0;
  height: 0;
  border-left: 50px solid transparent;
  border-right: 50px solid transparent;
  border-bottom: 100px solid #000;
  border-radius: 10px;
}

.triangle {
  position: relative;
  width: 100px;
  height: 100px;
}

.triangle::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-color: #000;
  border-radius: 10px;
  transform: rotate(45deg);
}

.triangle::after {
  content: "";
  position: absolute;
  top: 10px;
  left: 10px;
  width: 80%;
  height: 80%;
  background-color: #000;
  border-radius: 10px;
}