How can input type="submit" be made to take on a different form?

Question

css

The button for sending data to the server does not want to change the appearance of the button. I want to stretch it to full screen, make it wide, but it's still square. I tried different options for changing the class, I wrote the style in Input{, I tried other options in BUTTON {, I looked for a solution on the sites, they recommend it everywhere as indicated below, but this method does not work either. The color of the button changes, the color of the text, but it itself is still in the form of a typical square button. What's wrong?

<input class="MYbutton" type="submit" value="КНОПКА"></form>

input[type=submit] {
  display: block;
  margin: 0 auto;
  font-size: 1.5em;
  font-weight: bold;
  background: #2A2924;
  margin-bottom: 4px;
  padding: 16px;
  color: #F3E6D0;
  background: rgba(0,0,0, 0.3);
  -webkit-border-radius:8px;
  -moz-border-radius:8px;
  border-radius:8px;
}

Decided by adding to the class

width: 100%;
outline:none;
border: none;

The button stretched and the 3D button effect (shadow) disappeared, and it became flat, as intended.

Answer 1

Any button in the form will trigger the submit event - style it
Check the styles. In the code inspector.
Whether the file is connected.