body {
  margin: 0;
  height: 100vh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  font-family: "Microsoft YaHei", sans-serif;
  background-color: #f5f5f5;
}

h1 {
  margin-bottom: 20px;
}

.main-img {
  max-width: 80%;
  max-height: 60vh;
  border-radius: 12px;
  box-shadow: 0 10px 30px rgba(0,0,0,0.2);
}