datepicker/src/components/index/picker.css

.wrapper {
  font-family: "Chinese Quote", -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Helvetica, Arial, sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol";
  min-width: 170px;
  font-size: 14px;
  position: relative;
}
.container {
  width: 100%;
  cursor: text;
  overflow: hidden;
}
.input {
  width: 100%;
  height: 32px;
  margin: 0;
  padding: 4px 11px;
  outline: none;
  line-height: 1.5;
  box-sizing: border-box;
  font-size: 14px;
  color: rgba(0, 0, 0, 0.65);
  border: none;
  border-bottom: 1px solid #ccc;
}
.line {
  width: 100%;
  position: absolute;
  bottom: 0;
  left: 0;
  border-bottom: 1px solid #1890ff;
  transform: translateX(-100%);
  opacity: 0;
  will-change: transfrom;
  transition: transform .1s;
}
.container:hover {
  border-bottom: none;
}
.container:hover > .line {
  transform: translateX(0);
  opacity: 1;
}
.calendar {
  position: absolute;
  margin-top: 8px;
  right: 11px;
  display: inline-block;
  width: 16px;
  height: 16px;
  background-image: url('../../static/icon-calendar.svg');
  background-position: center; 
  background-size: 16px 16px;
  opacity: 1;
  transition: opacity .2s;
}
.close {
  position: absolute;
  margin-top: 8px;
  right: 11px;
  display: inline-block;
  width: 16px;
  height: 16px;
  background-image: url('../../static/icon-close.svg');
  background-position: center; 
  background-size: 16px 16px;
  cursor: pointer;
  opacity: 0;
  transition: opacity .2s;
}
.container:hover > .calendar {
  opacity: 0;
}
.container:hover > .close {
  opacity: 1;
}