@font-face {
  font-family: 'circular';
  src: url('../fonts/circular/CircularStd-Book.otf') format('opentype');
  font-weight: 400; /* 常规 */
  font-style: normal;
}
@font-face {
  font-family: 'circular';
  src: url('../fonts/circular/CircularStd-Medium.otf') format('opentype');
  font-weight: 500; /* 中等 */
  font-style: normal;
}
@font-face {
  font-family: 'circular';
  src: url('../fonts/circular/CircularStd-Bold.otf') format('opentype');
  font-weight: 700; /* 加粗 */
  font-style: normal;
}