html排版出问题怎么解决

制作的网页原来是这样：

img

一加导航条模板就变成这样：

img

排版出问题怎么回事？

index.html :

{% extends 'login/base.html' %} {% block title %}主页{% endblock %} {% block content %} {% if request.session.is_login %}
    <div class="search_bar clearfix">
        <a href="/index/" class="logo fl"><img src="/static/images/logo.png"></a>
         ........

base.html （base是模板文件）:

{% load static %}
<!DOCTYPE html>
<html lang="zh-CN">
<head>
    <meta charset="utf-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="">
    <!-- 上述3个meta标签*必须*放在最前面，任何其他内容都*必须*跟随其后！ -->
    <title>Bootstrap 101 Template</title>

    <!-- Bootstrap -->
    <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/3.4.1/css/bootstrap.min.css"
          integrity="sha384-HSMxcRTRxnN+Bdg0JdbxYKrThecOKuH5zCYotlSAcp1+c8xmyTe9GYg1l9a69psu" crossorigin="anonymous">

    <!-- HTML5 shim 和 Respond.js 是为了让 IE8 支持 HTML5 元素和媒体查询（media queries）功能 -->
    <!-- 警告：通过 file:// 协议（就是直接将 html 页面拖拽到浏览器中）访问页面时 Respond.js 不起作用 -->
    <!--[if lt IE 9]>
    <script src="https://fastly.jsdelivr.net/npm/html5shiv@3.7.3/dist/html5shiv.min.js"></script>
    <script src="https://fastly.jsdelivr.net/npm/respond.js@1.4.2/dest/respond.min.js"></script>
    <![endif]-->
</head>
<body>
<nav class="navbar navbar-default">
    <div class="container-fluid">
        <!-- Brand and toggle get grouped for better mobile display -->
        <div class="navbar-header">
            <button type="button" class="navbar-toggle collapsed" data-toggle="collapse" data-target="#my-nav"
                    aria-expanded="false">
                <span class="sr-only">切换导航条</span>
                <span class="icon-bar"></span>
                <span class="icon-bar"></span>
                <span class="icon-bar"></span>
            </button>
            <a class="navbar-brand" href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow"
               rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow"
               rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow"
               rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow"
               rel="external nofollow" rel="external nofollow" rel="external nofollow">Mysite</a>
        </div>

        <!-- Collect the nav links, forms, and other content for toggling -->
        <div class="collapse navbar-collapse" id="my-nav">
            <ul class="nav navbar-nav">
                <li class="active"><a href="/index/" rel="external nofollow" rel="external nofollow"
                                      rel="external nofollow">主页</a></li>
            </ul>
            <ul class="nav navbar-nav navbar-right">

                {% if request.session.is_login %}
                <li><a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow"
                       rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow"
                       rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow"
                       rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow"
                       rel="external nofollow" rel="external nofollow"
                       rel="external nofollow">当前在线：{{ request.session.user_name }}</a></li>
                <li><a href="/logout/" rel="external nofollow">退出</a></li>
                {% else %}

                <li><a href="/login" rel="external nofollow" rel="external nofollow" rel="external nofollow">登录</a>
                </li>
                <li><a href="/register/" rel="external nofollow" rel="external nofollow" rel="external nofollow">注册</a>
                </li>
                {% endif %}
            </ul>
        </div><!-- /.navbar-collapse -->
    </div><!-- /.container-fluid -->
</nav>

{% block content %}{% endblock %}

<!-- jQuery (Bootstrap 的所有 JavaScript 插件都依赖 jQuery，所以必须放在前边) -->
<script src="https://fastly.jsdelivr.net/npm/jquery@1.12.4/dist/jquery.min.js"
        integrity="sha384-nvAa0+6Qg9clwYCGGPpDQLVpLNn0fRaROjHqs13t4Ggj3Ez50XnGQqc/r8MhnRDZ"
        crossorigin="anonymous"></script>
<!-- 加载 Bootstrap 的所有 JavaScript 插件。你也可以根据需要只加载单个插件。 -->
<script src="https://stackpath.bootstrapcdn.com/bootstrap/3.4.1/js/bootstrap.min.js"
        integrity="sha384-aJ21OjlMXNL5UyIl/XNwTMqvzeRMZH2w8c5cRVpzpU8Y5bApTppSuUkhZXN0VxHd"
        crossorigin="anonymous"></script>

</body>
</html>

index.html 下面写的那一段代码和底下那个模块是一起的

应该是用了定位 吧 导致错位 。你审查元素看看