我的标题按钮（悬停时）和我想要 100% 的正文宽度有问题。请帮忙。谢谢你。
这是css，你可以在jsfiddle中看到html。
body {
background-color:rgba(0, 0, 0, 0.1);
font-family: "Alef Hebrew",
“Helvetica Neue”,
Helvetica,
Arial,
sans-serif;
}
#header {
left: 0;
top: 0px;
width: 100%;
height: 64px;
background: #007ac1;
position: fixed;
}
#header ul {
margin-left: 200px !important;
}
#x {
border-left: 1px solid rgba(0, 0, 0, 0.1);
box-shadow: 0px -1px 0px 1px rgba(255, 255, 255, 0.11);
text-decoration: underline;
}
.btn {
margin-left: -2px;
border-right: 1px solid rgba(0, 0, 0, 0.1);
box-shadow: 1px 0 0 rgba(255, 255, 255, 0.11);
color: white;
display: inline;
text-decoration: none;
padding: 25px;
transition: 0.5s;
font-weight:bold;
}
.btn:hover {
background: rgba(255,255,255,1);
color: #000;
}
#body {
padding: 100px;
width: 100%;
background: #fff;
float:left;
}