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

.calendar-date-time-input {
  .fake-input {
    display: none;
  }

  padding: 5px;
  border: 1px solid var(--primary-low);
  z-index: 1;
  background: var(--secondary);
  width: 200px;
  box-sizing: border-box;
  margin-left: 1em;

  .date-picker {
    display: flex;
    flex-direction: column;
    width: auto;
    box-sizing: border-box;

    .pika-single {
      position: relative !important;
      flex: 1;
      display: flex;
      border: 0;
    }
  }

  .time-pickers {
    display: flex;
    justify-content: center;
    flex: 1;
    margin-top: 1em;
    align-items: center;
    padding: 0.25em;
    border-top: 1px solid var(--primary-low-mid);
    box-sizing: border-box;

    .d-icon {
      color: var(--primary-medium);
      margin-right: 0.5em;
    }

    .time-picker {
      box-shadow: none;
      margin: 0;
      box-sizing: border-box;
      width: 100%;
    }
  }
}