老师，麻烦帮我看下哪里需要改进的，还有按钮应该怎么做

来源：4-4 自由编程

大白前端

2020-10-24 22:55:41

# 具体遇到的问题

# 报错信息的截图

# 相关课程内容截图

# 尝试过的解决思路和结果

# 粘贴全部相关代码，切记添加代码注释（请勿截图）

在这里输入代码，可通过选择【代码语言】
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title></title>
<link rel="stylesheet" href="base/base.css" />
<link rel="stylesheet" href="css/grid.css" />
<link rel="stylesheet" href="base/index.css" />
<style>
.header-container{
width: 100%;
background-color: #fff;
border-bottom: 1px solid #dadada;
}
img{
width: 200px;
}

.header-btn,
.header-nav,
.header-logo{
height: 60px;
}
.header-btn{
display: flex;
align-items: center;
justify-content:flex-start;
background-color: red;

}
.btn{
padding: 5px;
background-color: transparent;
border-radius: 4px;
border: none;
cursor: pointer;
}
.header-line{
display: block;
width: 30px;
height: 3px;
background-color: #fff;
border-radius: 2px;
}
.header-line + .header-line{
margin-top: 4px;
}
.header-logo{
display: flex;
align-items: center;
justify-content: center;
}

.header-link,
.header-item,
.header-item-i
{
height: 100%;
}
.header-link{
display: flex;
align-items: center;
justify-content: flex-start;
font-size: 14px;
}
.header-item{
margin-right: 24px;
}
.header-item:lase-child{
margin-right: 0;
}
.header-item-i{
display: flex;
align-items: center;
font-weight: bold;
}
.nav-contents{
overflow: hidden;
position: relative;
top: -1px;
height: 0;
border-bottom: 1px solid #dadada;
transition: height 1s;
}
.nav-content-extended{
top: 0;
height: 121px;
}
.nav-content{
display: block;
height: 40px;
line-height: 40px;
font-weight: bold;
}
</style>
</head>
<body>
<div class="header-container">

<div class="container">
<div class="row">
<div class="header-btn col-2 d-md-none">
<button type="button" class="btn" id="truggle">
<span class="header-line"></span>
<span class="header-line"></span>
</button>
</div>
<div class="header-nav col-md-8 d-none d-md-block col-md-2 col-lg-4">
<ul class="header-link">
<li class="header-item"><a href="###" class="header-item-i">首页</a></li>
<li class="header-item"><a href="###" class="header-item-i">关于</a></li>
<li class="header-item"><a href="###" class="header-item-i">商业合作</a></li>
</ul>
</div>
<div class="header-logo col-md-4">
<img src="img/logo.png"/>
</div>
</div>
</div>
</div>
<nav class="nav-contents d-md-none" id="nav">
<ul class="container">
<li><a href="###" class="nav-content">首页</a></li>
<li><a href="###" class="nav-content">关于</a></li>
<li><a href="###" class="nav-content">商业合作</a></li>
</ul>
</nav>
<script>
var nav = document.getElementById('nav');
var navName = 'nav-content-extended';

document.getElementById('truggle').onclick = function(){
if(nav.classList.contains(navName)){
nav.classList.remove(navName);
}else{
nav.classList.add(navName);
}
}
</script>
</body>
</html>
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