id里面的css div class(css div class inside id)

 我在使用我的CSS页面时遇到问题，它应该是一个几乎是白色的背景，它不会在我的课堂上显示。 我的代码： 
 
<div id="content">
<?php
$query="SELECT * FROM softwares ORDER BY Idsoft DESC LIMIT 5";
$result=mysqli_query($ligabd,$query);
while ($rows=mysqli_fetch_array($result))
{

$id=$rows["Idsoft"];
$a1=$rows["nome"];
$a2=$rows["marca"];
$a3=$rows["preco"];
$a4=$rows["stock"];
$a5=$rows["img"];
?>
<div class="img">

<a href="productprofile.php?id=<?php echo $id; ?>">

  <img src="<?php echo $a5;?>"  width="110" height="90">
  <div class="desc"><?php echo "".$a2." - ".$a1.""?></div>

</a>
</div>

<?php
}

?>
</div>
 
 在这里我的css： 
 
 #content
{
    width: 500px;
width: 80%;
height:1000;
margin: 0 auto 0 auto;
background-color:#999
overflow:hidden;
background-size:1980px 1080px;
}
 
 并为图像拼贴： 
 
   div.img
   {
   margin:5px;
   padding: 5px;
   border:1px solid #0000ff;
   height:auto;
   width:auto;
   float:left;
   text-align:center;
   }
   div.img img
   {
   display:inline;
   margin:5px;
   border:1px solid #ffffff;
   }
   div.img a:hover img
   {
   border:1px solid #0000ff;
   }
   div.desc
   {
   text-align:center;
   font-weight:normal;
   width:120px;
   margin:5px;
   }
 
 我的问题是内容中的背景应该出现在类下面，但我不能使它工作，已经尝试过而不是使用一个使用id的类但我不能格式化。 谁会帮助我，我将不胜感激！ 

i'm having problems using my css page, where it should be a almost white background it doesnt show in my class. my code:
 
<div id="content">
<?php
$query="SELECT * FROM softwares ORDER BY Idsoft DESC LIMIT 5";
$result=mysqli_query($ligabd,$query);
while ($rows=mysqli_fetch_array($result))
{

$id=$rows["Idsoft"];
$a1=$rows["nome"];
$a2=$rows["marca"];
$a3=$rows["preco"];
$a4=$rows["stock"];
$a5=$rows["img"];
?>
<div class="img">

<a href="productprofile.php?id=<?php echo $id; ?>">

  <img src="<?php echo $a5;?>"  width="110" height="90">
  <div class="desc"><?php echo "".$a2." - ".$a1.""?></div>

</a>
</div>

<?php
}

?>
</div>
 
and here my css:
 
 #content
{
    width: 500px;
width: 80%;
height:1000;
margin: 0 auto 0 auto;
background-color:#999
overflow:hidden;
background-size:1980px 1080px;
}
 
and for the image tiles:
 
   div.img
   {
   margin:5px;
   padding: 5px;
   border:1px solid #0000ff;
   height:auto;
   width:auto;
   float:left;
   text-align:center;
   }
   div.img img
   {
   display:inline;
   margin:5px;
   border:1px solid #ffffff;
   }
   div.img a:hover img
   {
   border:1px solid #0000ff;
   }
   div.desc
   {
   text-align:center;
   font-weight:normal;
   width:120px;
   margin:5px;
   }
 
my problem is that the background in the content should appear under the class, but i cant make it work, already tried to instead of using a class using an id but i cant format. i'll be appreciated by who helped me!

原文：