<!DOCTYPE html>
<html>
<head>
<style>
 .none { -moz-appearance: none; }
 input, button { width: 1.5em; padding: 0; font-size: 14px; }
</style>
</head>
<body>
  <input class="none" type="button" value="M"><br>
  <input class="none" type="button" value="M"><br>

  <input class="none" type="button" value="Long Text"><br>
  <input class="none" type="button" value="Long Text"><br>

  <input type="button" value="M"><br>
  <input type="button" value="M"><br>

  <input type="button" value="Long Text"><br>
  <input type="button" value="Long Text"><br>

  <button class="none" type="button">M</button><br>
  <button class="none" type="button">M</button><br>

  <button class="none" type="button">Long Text</button><br>
  <button class="none" type="button">Long Text</button><br>

  <button type="button">M</button><br>
  <button type="button">M</button><br>

  <button type="button">Long Text</button><br>
  <button type="button">Long Text</button><br>

</body>
</html>