* {
  box-sizing: border-box;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI",
    Roboto, Helvetica, Arial, sans-serif;
}

body {
  margin: 0;
  height: 100vh;
  background: linear-gradient(135deg, #0f0f0f, #2a2a2a);
  display: flex;
  align-items: center;
  justify-content: center;
}

.login-container {
  background: #ffffff;
  padding: 40px 35px;
  width: 320px;
  border-radius: 12px;
  text-align: center;
  box-shadow: 0 20px 45px rgba(0, 0, 0, 0.45);
}

.login-container h1 {
  margin: 0 0 10px;
  font-size: 24px;
}

.login-container p {
  margin-bottom: 20px;
  color: #555;
  font-size: 14px;
}

input {
  width: 100%;
  padding: 14px;
  font-size: 22px;
  text-align: center;
  letter-spacing: 8px;
  border: 1px solid #ccc;
  border-radius: 6px;
  margin-bottom: 15px;
  outline: none;
}

input:disabled {
  background: #f2f2f2;
  cursor: not-allowed;
}

button {
  width: 100%;
  padding: 14px;
  font-size: 16px;
  background: #111;
  color: #fff;
  border: none;
  border-radius: 6px;
  cursor: pointer;
  transition: background 0.2s ease;
}

button:hover:not(:disabled) {
  background: #333;
}

button:disabled {
  background: #999;
  cursor: not-allowed;
}

.error {
  margin-top: 15px;
  font-size: 13px;
  color: #c0392b;
  min-height: 18px;
}