我的页面上有一个黑色的主题/灯光主题按钮，但页面顶部有一个空白区域。我想删除那个空格，并希望效果在整页中应用。
以下是它的代码（顶部是HTML，底部是CSS）： http://pastebin.com/GL4vvUQN
body {
margin: 0px;
padding: 0px;
overflow-y: scroll;
font-family: Helvetica;
font-size: 18px;
background-color: #bdbdbd;
}
.nav {
background-color: #222;
position: relative;
width: 100%;
}
.nav_wrapper {
width: 960px;
margin: 0 auto;
text-align: left;
}
.nav ul {
list-style-type: none;
padding: 0;
margin: 0;
position: relative;
}
.nav ul li {
display: inline-block;
background-color: #222;
transition: background-color 0.3s ease-in;
position: relative;
padding-top: 3px;
padding-bottom: 3px;
}
.nav ul li img {
width: 12px;
height: 10px;
vertical-align: middle;
padding-left: 10px;
}
.nav ul li a,
visited {
display: block;
padding: 15px;
text-decoration: none;
transition: color 0.2s ease-in;
}
.nav ul li a:hover {
text-decoration: none;
color: #099;
}
.navhome {
color: #099;
border-bottom: 3px solid #099;
}
.navother {
color: #ccc;
}
.content {
text-align: center;
line-height: 130%;
font-size: 20px;
}
.bdaimg {
width: 50%;
display: block;
margin-left: auto;
margin-right: auto;
margin-bottom: 40px;
margin-top: 30px;
transform: scale(1);
transition-duration: 0.3s;
border-radius: 15px;
}
.bdaimg:hover {
transform: scale(1.1);
transition-duration: 0.3s;
}
.nu {
font-weight: bold;
font-size: 25px;
}
h3 {
font-weight: bold;
text-decoration: underline;
}
h2 {
font-weight: bold;
text-decoration: underline;
}
.bdaimg2 {
display: block;
margin-left: auto;
margin-right: auto;
margin-bottom: 40px;
margin-top: 30px;
transform: scale(1);
transition-duration: 0.3s;
border-radius: 15px;
}
.bdaimg2:hover {
transform: scale(1.1);
transition-duration: 0.3s;
}
/*Light Switch*/
label {
display: block;
height: 25px;
width: 100px;
background: white;
text-align: center;
font: 14px/25px Helvetica, Arial, sans-serif;
margin: 20px 0;
position: absolute;
}
label:hover {
background: #ddca7e;
color: white;
cursor: pointer;
}
input#lightswitch {
position: fixed;
top: -9999px;
left: -9999px;
}
input#lightswitch + .content {
background-color: #bdbdbd;
transition: background-color 0.5s ease-in;
}
/*Switched Off*/
input#lightswitch:checked + .content {
background-color: #222;
transition: background-color 0.5s ease-in;
}
input#lightswitch:checked + .content {
color: white;
}
input#lightswitch:checked + .content {
color: white;
}<!DOCTYPE html>
<head>
<title>Beijing Dance Academy</title>
<link rel="stylesheet" type="text/css" href="bda.css">
</head>
<body>
<div class="nav">
<div class="nav_wrapper">
<ul>
<li><a class="navother" href="Home.html">Home</a>
</li>
<li><a class="navother" href="CR.html">Cultural Revolution</a>
</li>
<li><a class="navhome" href="BDA.html">Beijing Dance Academy</a>
</li>
<li><a class="navother" href="CNY.html">Chinese New Year</a>
</li>
</ul>
</div>
</div>
<label for="lightswitch">Light Switch</label>
<input type="checkbox" id="lightswitch" />
<div class="content">
<img src="bda.png" alt="BDA" class="bdaimg">
<p>
<h2>Beijing Dance Academy</h2>
Beijing Dance Academy, or BDA, was the first professional dance school founded in China, in 1954. The academy was helped by Soviet Russia in building the academy and the techniques they used to learn dance. Although Russia helped with the Beijing Dance
Academy, China's repressive Communist government forbidded Russian presence in the school. The Beijing Dance Academy soon opened back up to all people from around the world when, in 1976, China's Communist leader, Mao Zedong, died.
<br>
<br>Several times a year, Beijing Dance Academy holds auditions to be accepted into the school, for more disadvantaged areas officals come around small towns and schools and pick out children of age, the academy initially only accepted students from
ages 11 to 18 but eventually the age range expanded. They then test the student's basic body abilities. More than 2,000 children audition to be accepted into the academy but only 1 in every 20 make the cut. Majority of the children in the academy
are Chinese but the academy has an additional program that allows international students to apply.
<br>
<br>
<h3>
A Day in the Life of a Student
</h3>
A day of a Beijing Dance Academy student starts with basic warm-ups and stretches such as flexibility exercises and drills for turns and jumps. After breakfast, the students have a ballet technique class followed by character dance or pas de deux exercises.
Then after lunch, the students study normal subjects such as mathematics or Chinese for 3 hours. In the afternoon, they have repertory classes or study or do homework. The Beijing Dance Academy is run for the whole week...
</p>
<p class="nu">
INCLUDING SATURDAY AND SUNDAY!
<img src="sadface.png" alt="SpongebobSadFace" class="bdaimg2">
</p>
</div>
</body>
答案 0 :(得分：0)
尝试添加负边距以删除该空白sapce，如下所示：
.content {
text-align: center;
line-height: 130%;
font-size: 20px;
margin-top: -30px;
}
以下是改进的代码：
body {
margin: 0px;
padding: 0px;
overflow-y: scroll;
font-family: Helvetica;
font-size: 18px;
background-color: #bdbdbd;
}
.nav {
background-color: #222;
position: relative;
width: 100%;
}
.nav_wrapper {
width: 960px;
margin: 0 auto;
text-align: left;
}
.nav ul {
list-style-type: none;
padding: 0;
margin: 0;
position: relative;
}
.nav ul li {
display: inline-block;
background-color: #222;
transition: background-color 0.3s ease-in;
position: relative;
padding-top: 3px;
padding-bottom: 3px;
}
.nav ul li img {
width: 12px;
height: 10px;
vertical-align: middle;
padding-left: 10px;
}
.nav ul li a,
visited {
display: block;
padding: 15px;
text-decoration: none;
transition: color 0.2s ease-in;
}
.nav ul li a:hover {
text-decoration: none;
color: #099;
}
.navhome {
color: #099;
border-bottom: 3px solid #099;
}
.navother {
color: #ccc;
}
.content {
text-align: center;
line-height: 130%;
font-size: 20px;
margin-top: -30px;
}
.bdaimg {
width: 50%;
display: block;
margin-left: auto;
margin-right: auto;
margin-bottom: 40px;
margin-top: 30px;
transform: scale(1);
transition-duration: 0.3s;
border-radius: 15px;
}
.bdaimg:hover {
transform: scale(1.1);
transition-duration: 0.3s;
}
.nu {
font-weight: bold;
font-size: 25px;
}
h3 {
font-weight: bold;
text-decoration: underline;
}
h2 {
font-weight: bold;
text-decoration: underline;
}
.bdaimg2 {
display: block;
margin-left: auto;
margin-right: auto;
margin-bottom: 40px;
margin-top: 30px;
transform: scale(1);
transition-duration: 0.3s;
border-radius: 15px;
}
.bdaimg2:hover {
transform: scale(1.1);
transition-duration: 0.3s;
}
/*Light Switch*/
label {
display: block;
height: 25px;
width: 100px;
background: white;
text-align: center;
font: 14px/25px Helvetica, Arial, sans-serif;
margin: 20px 0;
position: absolute;
}
label:hover {
background: #ddca7e;
color: white;
cursor: pointer;
}
input#lightswitch {
position: fixed;
top: -9999px;
left: -9999px;
}
input#lightswitch + .content {
background-color: #bdbdbd;
transition: background-color 0.5s ease-in;
}
/*Switched Off*/
input#lightswitch:checked + .content {
background-color: #222;
transition: background-color 0.5s ease-in;
}
input#lightswitch:checked + .content {
color: white;
}
input#lightswitch:checked + .content {
color: white;
}<!DOCTYPE html>
<head>
<title>Beijing Dance Academy</title>
<link rel="stylesheet" type="text/css" href="bda.css">
</head>
<body>
<div class="nav">
<div class="nav_wrapper">
<ul>
<li><a class="navother" href="Home.html">Home</a>
</li>
<li><a class="navother" href="CR.html">Cultural Revolution</a>
</li>
<li><a class="navhome" href="BDA.html">Beijing Dance Academy</a>
</li>
<li><a class="navother" href="CNY.html">Chinese New Year</a>
</li>
</ul>
</div>
</div>
<label for="lightswitch">Light Switch</label>
<input type="checkbox" id="lightswitch" />
<div class="content">
<img src="bda.png" alt="BDA" class="bdaimg">
<p>
<h2>Beijing Dance Academy</h2>
Beijing Dance Academy, or BDA, was the first professional dance school founded in China, in 1954. The academy was helped by Soviet Russia in building the academy and the techniques they used to learn dance. Although Russia helped with the Beijing Dance
Academy, China's repressive Communist government forbidded Russian presence in the school. The Beijing Dance Academy soon opened back up to all people from around the world when, in 1976, China's Communist leader, Mao Zedong, died.
<br>
<br>Several times a year, Beijing Dance Academy holds auditions to be accepted into the school, for more disadvantaged areas officals come around small towns and schools and pick out children of age, the academy initially only accepted students from
ages 11 to 18 but eventually the age range expanded. They then test the student's basic body abilities. More than 2,000 children audition to be accepted into the academy but only 1 in every 20 make the cut. Majority of the children in the academy
are Chinese but the academy has an additional program that allows international students to apply.
<br>
<br>
<h3>
A Day in the Life of a Student
</h3>
A day of a Beijing Dance Academy student starts with basic warm-ups and stretches such as flexibility exercises and drills for turns and jumps. After breakfast, the students have a ballet technique class followed by character dance or pas de deux exercises.
Then after lunch, the students study normal subjects such as mathematics or Chinese for 3 hours. In the afternoon, they have repertory classes or study or do homework. The Beijing Dance Academy is run for the whole week...
</p>
<p class="nu">
INCLUDING SATURDAY AND SUNDAY!
<img src="sadface.png" alt="SpongebobSadFace" class="bdaimg2">
</p>
</div>
</body>
答案 1 :(得分：0)
问题是你的img与src =＆＃34; bda.png＆＃34;有一个30px的上边距。
这是html中的一些奇怪的行为，它不会将图像向下移动30px，但它会将图像的父级向下移动30px。
要解决此问题，您可以将图像的margin-top设置为0px并使用div的padding-top将其向下移动，或者可以将包含div的display-property设置为＆＃34; display ：inline-block＆＃34;。像这样：
.content {
text-align: center;
line-height: 130%;
font-size: 20px;
display: inline-block;
}