我想在“描述”类中向下滚动时修复“标题”类。但是当我添加“position：fixed;”时在css中，标题类变小。我怎样才能克服这个问题？
body {
margin: 0px;
padding: 0px;
}
.mainHeader {
background: #aea5af;
padding: 20px 0px;
margin: 0 auto;
border-bottom: 10px dotted black;
}
.mainArea {
max-width: 1180px;
margin: 0 auto;
}
.mainArea:after {
content: '';
display: block;
clear: both;
}
.mainHeader:after {
content: '';
display: block;
clear: both;
}
.logoArea {
float: left;
width: 30%;
}
.headerRightArea {
float: right;
width: 70%;
text-align: right;
}
input {
padding: 5px;
border-radius: 50px;
border: 1px solid black;
}
input[type="submit"] {
padding: 5px 10px;
color: #ffffff;
background-color: #fff200;
font-weight: bold;
}
.oneHalf {
width: 50%;
float: left;
overflow: scroll;
display: block;
height: 400px;
}
.scrollbox {
background: blue;
border-radius: 20px;
}
.bg_image {
background: #34675C;
height: 800px;
padding: 30px 30px;
}
.heading {
display: block;
background: #6AB187;
font-style: italic;
font-weight: bold;
text-align: center;
font-size: 45px;
position: static;
border-radius: 20px;
}
.description {
color: #021C1E;
font-size: 29px;
font-style: italic;
font-weight: bold;
text-align: center;
}
#tt {
text-align: center;
height: 300px;
width: 300px;
border-radius: 50%;
background-attachment: fixed;
}<!DOCTYPE HTML>
<html lang="en-US">
<head>
<meta charset="UTF-8">
<title>Class 6</title>
<link rel="stylesheet" type="text/css" href="style.css" media="all" />
</head>
<body>
<!--Header Area Start-->
<header class="mainHeader">
<div class="mainArea">
<div class="logoArea">
<a href="#">
<img src="CN_Logo.png" alt="CN_Logo.png" height="100px" width="200px" />
</a>
</div>
<div class="headerRightArea">
<form action="#">
<input type="text" placeholder="User Name" name="user" />
<input type="password" placeholder="Password" name="password" />
<input type="submit" value="Sign In" />
</form>
</div>
</div>
</header>
<!--Header Area End-->
<!--Section Area Start-->
<section class="bg_image">
<div class="mainArea">
<div class="row">
<div class="oneHalf">
<div class="scrollbox">
<div class="heading">
Hello, Cartoon Fans
</div>
<div class="description">
Cartoon Network is an American basic cable and satellite television channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television
channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television channel that is owned by Time Warner through the
Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was
launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is
an American basic cable and satellite television channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television
channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television channel that is owned by Time Warner through the
Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was
launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is
an American basic cable and satellite television channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television
channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television channel that is owned by Time Warner through the
Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was
launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is
an American basic cable and satellite television channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television
channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television channel that is owned by Time Warner through the
Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was
launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is
an American basic cable and satellite television channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television
channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television channel that is owned by Time Warner through the
Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was
launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is
an American basic cable and satellite television channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television
channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television channel that is owned by Time Warner through the
Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was
launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is
an American basic cable and satellite television channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television
channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television channel that is owned by Time Warner through the
Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was
launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is
an American basic cable and satellite television channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television
channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television channel that is owned by Time Warner through the
Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was
launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is
an American basic cable and satellite television channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television
channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television channel that is owned by Time Warner through the
Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was
launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is
an American basic cable and satellite television channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television
channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television channel that is owned by Time Warner through the
Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was
launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is
an American basic cable and satellite television channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television
channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television channel that is owned by Time Warner through the
Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was
launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is
an American basic cable and satellite television channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television
channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television channel that is owned by Time Warner through the
Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was
launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is
an American basic cable and satellite television channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television
channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television channel that is owned by Time Warner through the
Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was
launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is
an American basic cable and satellite television channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television
channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television channel that is owned by Time Warner through the
Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was
launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is
an American basic cable and satellite television channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television
channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television channel that is owned by Time Warner through the
Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was
launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is
an American basic cable and satellite television channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television
channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television channel that is owned by Time Warner through the
Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was
launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is
an American basic cable and satellite television channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television
channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television channel that is owned by Time Warner through the
Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was
launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is
an American basic cable and satellite television channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television
channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television channel that is owned by Time Warner through the
Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was
launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is
an American basic cable and satellite television channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television
channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television channel that is owned by Time Warner through the
Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was
launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is
an American basic cable and satellite television channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television
channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television channel that is owned by Time Warner through the
Turner Broadcasting System subsidiary. It was launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was
launched on October 1, 1992.Cartoon Network is an American basic cable and satellite television channel that is owned by Time Warner through the Turner Broadcasting System subsidiary. It was launched on October 1, 1992.
</div>
</div>
</div>
<div class="lastHalf">
<div class="center">
<img id="tt" src="cartoon_network.jpg" alt="cartoon_network.jpg" id="section_right" />
</div>
</div>
</div>
</div>
</section>
</body>
</html>