css绘制常见的一些图形

.line {
  width: 100px;
  height: 1px;
  background-color: black;
}

.arrow {
  width: 0;
  height: 0;
  border-top: 10px solid transparent;
  border-bottom: 10px solid transparent;
  border-right: 10px solid black;
}

.triangle {
  width: 0;
  height: 0;
  border-top: 50px solid transparent;
  border-left: 50px solid black;
  border-bottom: 50px solid transparent;
}

.rectangle {
  width: 100px;
  height: 50px;
  background-color: black;
}

.circle {
  width: 50px;
  height: 50px;
  border-radius: 50%;
  background-color: black;
}

.ellipse {
  width: 100px;
  height: 50px;
  border-radius: 50%;
  background-color: black;
}

.parallelogram {
  width: 100px;
  height: 50px;
  transform: skewX(20deg);
  background-color: black;
}

.rhombus {
  width: 0;
  height: 0;
  border: 50px solid black;
  border-right-color: transparent;
  border-left-color: transparent;
  transform: rotate(45deg);
}

.trapezoid {
  width: 100px;
  height: 0;
  border-top: 50px solid black;
  border-left: 25px solid transparent;
  border-right: 25px solid transparent;
}