mainscreen.css

*,
*::before,
*::after {
  box-sizing: border-box;
  user-select: none;
}

body {
  margin: 0;
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
  text-align: center;
  font-family: Verdana, sans-serif;
}

input[type="text"] {
  padding: 10px;
  margin: 10px;
  border-radius: 5px;
  border: 1px solid #ccc;
  width: 200px;
}
button {
  padding: 10px 20px;
  margin: 10px;
  border-radius: 5px;
  border: none;
  cursor: pointer;
  font-size: 16px;
  width: 200px;
}
button:hover {
  background-color: #ffd900;
}