Build an age calculator that takes a birth date as input and displays the exact age in years, months, and days.
The user should enter their birth date using a date input. On submit, the app calculates how many years, months, and days have passed since that date and shows the result clearly.
Handle edge cases such as invalid or future dates, and make sure the calculation accounts for month lengths and leap years correctly.
Focus on date arithmetic: compute the difference in years, then the remaining months, then the remaining days.
Make the result display prominent and update when a new date is entered.
