.container {
  --border: 2px solid var(--some-black-color, #757575);
  --radius: 0.4rem;
  --width: min(28rem, 100%);

  --width-day: 6rem;
  --width-month: 6rem;
  --width-year: 8rem;

  display: grid;
  gap: 0.8rem;
  grid-template-areas: "day month year";
  grid-template-columns: min(--width-day, 1fr) min(--width-month, 1fr) min(
      --width-year,
      2fr
    );
  width: var(--width);
}

.day {
  grid-area: day;
}

.month {
  grid-area: month;
}

.year {
  grid-area: year;
}