/* 页面背景和底部 */
body {
  margin: 0;
  padding: 0;
  font-family: 'Segoe UI', sans-serif;
  background: url('image/main-bg.jpeg') no-repeat center center fixed;
  background-size: cover;
  color: #f1f1f1;
  display: flex;
  flex-direction: column;
  height: 100%;
}

/* 内容区域 */
.main-content {
  flex: 1; /* 确保内容区域占满剩余空间 */
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  text-align: center;
}

/* 卡片背景优化 */
.welcome-box {
  background: rgba(0, 0, 0, 0.7); /* 调整为稍微透明的背景 */
  border-radius: 16px;
  padding: 40px;
  max-width: 720px;
  width: 100%;
  backdrop-filter: blur(10px); /* 背景模糊 */
  box-shadow: 0 8px 30px rgba(0, 0, 0, 0.6); /* 增强阴影效果 */
}

/* footer 样式优化 */
footer {
  background: rgba(15, 32, 39, 0.8); /* 背景变得更加不透明 */
  color: #fff;
  padding: 20px 0;
  width: 100%;
  text-align: center;
  position: relative;
  z-index: 10;
  bottom: 0;
  margin-top: auto;
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.3);
}

footer a {
  color: #7ecbff;
  text-decoration: none;
}

footer a:hover {
  text-decoration: underline;
}

footer small {
  font-weight: 300;
  letter-spacing: 0.5px;
  color: #d1d5db;
}

/* 优化按钮 */
.welcome-box .btn {
  margin: 10px 0;
  padding: 12px 24px;
  font-size: 1rem;
  font-weight: 600;
  transition: background-color 0.3s ease;
}

.welcome-box .btn:hover {
  background-color: #4b6b8a; /* 悬停时背景颜色变更 */
}

/* 页面底部始终固定 */
body {
  display: flex;
  flex-direction: column;
  height: 100%;
}

.main-content {
  flex: 1;
  display: flex;
  justify-content: center;
  align-items: center;
  padding: 40px 20px;
}

footer {
  margin-top: auto;
  padding: 20px;
  background-color: rgba(15, 32, 39, 0.8);
  color: white;
}