.submit-btn {
    width: 100%; /* Make the button fill the container */
    display: block; /* Ensures the button is a block-level element */
    box-sizing: border-box; /* Ensures padding and border are included in the width */
    display: flex;
    align-items: center;
    justify-content: center;
    height: 50px; /* Set the height you want */
  }