/* Reset */
* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html, body {
  height: 100%;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen,
    Ubuntu, Cantarell, "Open Sans", "Helvetica Neue", sans-serif;
  background-color: #f5f7fa;
  color: #2e3a59;
  display: flex;
  justify-content: center;
  align-items: center;
  padding: 1rem;
}

.error-container {
  max-width: 360px;
  text-align: center;
  padding: 2rem;
  background-color: #fff;
  border: 1px solid #d1d9e6;
  border-radius: 12px;
  box-shadow: 0 10px 25px rgba(46, 58, 89, 0.1);
}

.error-code {
  font-size: 6rem;
  font-weight: 700;
  color: #6c757d;
  margin-bottom: 1rem;
  user-select: none;
}

.error-message h1 {
  font-size: 1.75rem;
  margin-bottom: 0.5rem;
  font-weight: 600;
}

.error-message p {
  font-size: 1rem;
  margin-bottom: 1.5rem;
  color: #495057;
  line-height: 1.4;
}

.btn {
  display: inline-block;
  padding: 0.6rem 1.6rem;
  font-weight: 600;
  font-size: 1rem;
  color: #fff;
  background: linear-gradient(90deg, #4a90e2, #357ABD);
  border-radius: 8px;
  text-decoration: none;
  transition: background 0.3s ease;
  box-shadow: 0 4px 12px rgba(53, 122, 189, 0.4);
}

.btn:hover,
.btn:focus {
  background: linear-gradient(90deg, #357ABD, #2c5a9c);
  box-shadow: 0 6px 20px rgba(44, 90, 156, 0.6);
  outline: none;
}