body {
  font-family: Arial, "Microsoft YaHei", sans-serif;
  background: #f5f6f8;
  color: #111827;
}

.container, main, section {
  max-width: 720px;
  margin: 40px auto;
  background: #fff;
  border-radius: 14px;
  padding: 28px;
  box-shadow: 0 10px 30px rgba(0,0,0,.06);
}

button, input[type="submit"] {
  background: #111827;
  color: #fff;
  border: 0;
  border-radius: 8px;
  padding: 10px 18px;
  cursor: pointer;
}

a {
  color: #2563eb;
}