discourse/app/assets/stylesheets/common/components/date-input.scss

.d-date-input {
  display: inline-flex;
  cursor: pointer;
  flex-direction: column;
  min-width: 140px;

  .date-picker {
    cursor: pointer;
    margin: 0;
    text-align: left;
    width: 100%;
    box-shadow: none !important;

    &::-webkit-input-placeholder {
      font-size: $font-0;
      color: $primary-medium;
    }

    &::-ms-input-placeholder {
      font-size: $font-0;
      color: $primary-medium;
    }

    &::placeholder {
      font-size: $font-0;
      color: $primary-medium;
    }

    &:focus {
      outline: 1px solid $tertiary;
      outline-offset: 0;
    }
  }

  .pika-single {
    margin-left: -1px;
    margin-top: 1px;

    .pika-row td {
      .pika-button.pika-day {
        box-shadow: none;
        border-radius: 0;
      }
    }
  }
}

.d-date-input + .d-time-input {
  margin-left: 1px;
}

.d-time-input + .d-date-input {
  margin-left: 1px;
}

.d-date-input + .clear-date-time {
  margin-left: 1px;
}