html {/*网页属性*/
  scroll-behavior: smooth;  /* 启用平滑滚动 */
}
body{
    background: linear-gradient(135deg, #fdfdfd, #8fa0eb);
    background-repeat: no-repeat;
    background-size: cover;
    background-attachment: fixed;
}

img{
    width: 500px;
    border-radius: 10px;
}
.tie{
    background-color: aqua;
    margin: 0;
    border: 0;
    padding: 0;
    width: 100%;
    height: 20px;
    border-radius: 10px 10px 0 0 ;
}

.container{
  display: grid;
  
  grid-template-areas:
    "header header"   /* 头部占满一行 */
    "sidebar content" /* 侧边栏 + 主内容 */
    "footer footer"; 
    grid-template-columns: 1fr 4fr;
    grid-template-rows: auto 1fr auto;
    min-height: 100vh;
}
.header{
    grid-area: header;
    background: #66eff442;
    align-items: center;
    text-align: center;
    border-radius: 0 0 10px 10px;
}
.content{
    grid-area: content;
    display: grid;
    padding: 20px;
    grid-template-columns: 3fr 1fr;

}
.sidebar {
    margin-left: 20px;
    grid-area: sidebar;
    top: 0;


}
.footer{
    grid-area:footer;
    text-align: center;
    margin: 0;
}
.page{
    display: flex;
    flex-direction: column;
    align-items: center;
}
.audio{
    margin: 5px;
}
/*主页面元素*/
#musicBtn{
  width: 50px;
}

#back-to-top{
  position: fixed; /* 固定定位 */
  bottom: 30px;    /* 距离底部 */
  right: 30px;     /* 距离右侧 */
  width: 50px;
  height: 50px;
  border: none;
  border-radius: 50%; /* 圆形按钮 */
  background-color: #0b487a; /* 背景色 */
  color: white;
  font-size: 18px;
  cursor: pointer;
  opacity: 0;      /* 默认隐藏 */
  transition: opacity 0.3s, background-color 0.3s; /* 平滑过渡 */
}
#back-to-top:hover {
  background-color: #555; /* 悬停颜色 */
}
#back-to-top.show {
  opacity: 1; /* 显示按钮 */
}
.img{
  display: flex;
  justify-content: center;
}
/*项目页面*/
.change-page{
  background-color:#1596ff;
  color: white;
  border-radius: 10px;
  border:0;
}
.change-page:hover{
  background-color: #1259af;
}
.dalian{
  background-color: rgba(255, 255, 255, 0);
  border-radius: 3px;
  margin: 2px;
}
#dalian_bus{
  display: flex;
  flex-direction: column;
  justify-content: center;
}
.label{
  font: size 1px;;
  text-align: center;
  margin-top: 0;
  margin-bottom: 20px;
}
/*表单页面*/
.error{
  color: red;
  margin-top: 10px;
}
.success{
  color: green;
  margin-top: 10px;
}

@media (max-width: 600px) {
  .container {
    grid-template-areas:
      "header"
      "content"
      "sidebar"
      "footer";
    grid-template-columns: 1fr;
  }

  .content {
    grid-template-columns: 1fr;
    align-items: center; /* 移动端单列布局 */
    
  }
  .img{
  display: flex;
  justify-content: center;
}
  img{
    width: 400px;
    border-radius: 10px;
  }

}