ant-design/style/components/datepicker/Calendar.less

.calendarPanelHeader(@calendar-prefix-cls) {
  padding: 0 10px;
  height: 34px;
  line-height: 34px;
  text-align: center;
  user-select: none;
  border-bottom: 1px solid #e9e9e9;

  a:hover {
    color: @link-hover-color;
  }

  .@{calendar-prefix-cls}-century-select,
  .@{calendar-prefix-cls}-decade-select,
  .@{calendar-prefix-cls}-year-select,
  .@{calendar-prefix-cls}-month-select {
    padding: 0 2px;
    font-weight: bold;
    display: inline-block;
    color: #666;
    line-height: 34px;
  }

  .@{calendar-prefix-cls}-century-select-arrow,
  .@{calendar-prefix-cls}-decade-select-arrow,
  .@{calendar-prefix-cls}-year-select-arrow,
  .@{calendar-prefix-cls}-month-select-arrow {
    display: none;
  }

  .@{calendar-prefix-cls}-prev-century-btn,
  .@{calendar-prefix-cls}-next-century-btn,
  .@{calendar-prefix-cls}-prev-decade-btn,
  .@{calendar-prefix-cls}-next-decade-btn,
  .@{calendar-prefix-cls}-prev-month-btn,
  .@{calendar-prefix-cls}-next-month-btn,
  .@{calendar-prefix-cls}-prev-year-btn,
  .@{calendar-prefix-cls}-next-year-btn {
    position: absolute;
    top: 0;
    color: #999;
    font-family: Arial,"Hiragino Sans GB","Microsoft Yahei","Microsoft Sans Serif",sans-serif;
    padding: 0 5px;
    font-size: 16px;
    display: inline-block;
    line-height: 34px;
  }

  .@{calendar-prefix-cls}-prev-century-btn,
  .@{calendar-prefix-cls}-prev-decade-btn,
  .@{calendar-prefix-cls}-prev-year-btn {
    left: 7px;
  }

  .@{calendar-prefix-cls}-next-century-btn,
  .@{calendar-prefix-cls}-next-decade-btn,
  .@{calendar-prefix-cls}-next-year-btn {
    right: 7px;
  }

  .@{calendar-prefix-cls}-prev-month-btn {
    left: 29px;
  }

  .@{calendar-prefix-cls}-next-month-btn {
    right: 29px;
  }
}

.@{calendar-prefix-cls} {
  position: relative;
  outline: none;
  width: 253px;
  border: 1px solid #ccc;
  list-style: none;
  font-size: @font-size-base;
  text-align: left;
  background-color: #fff;
  border-radius: @border-radius-base;
  box-shadow: @overlay-shadow;
  background-clip: padding-box;
  line-height: @line-height-base;

  &-week-number {
    width: 286px;

    &-cell {
      text-align: center;
    }
  }

  &-header {
    .calendarPanelHeader(@calendar-prefix-cls);
  }

  &-calendar-body {
    padding: 5px 8px;
  }

  table {
    border-collapse: collapse;
    max-width: 100%;
    background-color: transparent;
    width: 100%;
  }

  table, td, th, td {
    border: none;
  }

  &-calendar-table {
    border-spacing: 0;
    margin-bottom: 0;
  }

  &-column-header {
    line-height: 18px;
    width: 33px;
    padding: 6px 0;
    text-align: center;
    .@{calendar-prefix-cls}-column-header-inner {
      display: block;
      font-weight: normal;
    }
  }

  &-week-number-header {
    .@{calendar-prefix-cls}-column-header-inner {
      display: none;
    }
  }

  &-cell {
    padding: 4px 0;
  }

  &-date {
    display: block;
    margin: 0 auto;
    color: #666;
    border-radius: 4px 4px;