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Here is an example of the process for automatically synchronizing the resizing of two textareas using JS and CSS:

1. First, create a HTML document with two textareas, each with a unique id:

<textarea id="textarea1"></textarea>
<textarea id="textarea2"></textarea>

1. Add CSS to the document to set the height of the textareas to be equal:

textarea {
  height: 200px;
}

1. Add an event listener to the textareas that will trigger a function whenever the text in the textarea changes:

const textarea1 = document.getElementById('textarea1');
const textarea2 = document.getElementById('textarea2');

textarea1.addEventListener('input', syncTextAreaHeight);
textarea2.addEventListener('input', syncTextAreaHeight);

1. Create a function that will set the height of both textareas to be equal to the height of the textarea with the largest amount of text:

function syncTextAreaHeight() {
  const height = Math.max(textarea1.scrollHeight, textarea2.scrollHeight);
  textarea1.style.height = height + 'px';
  textarea2.style.height = height + 'px';
}

1. Test the textareas by typing text in one textarea and checking that the other resizes to match the height of the first.

2. You may need to adjust the CSS if the textareas do not resize properly.

Note: This is just one example of how to automatically synchronize the resizing of two textareas. There are many other ways to achieve the same effect.