我试图在父div中创建一个具有不同背景颜色的右浮动边栏。父元素有一个3px的虚线边框，并且侧边栏没有一直延伸到边缘。相反，父元素的背景颜色在破折号之间可见。
网站主体的视图
拐角的近景，显示背景不满足边框的边缘
我试过调整位置，改变元素的顺序，改变高度和宽度，我有点不知所措。
body {
background-image: url("https://i.lensdump.com/i/Rxu5rz.png");
}
@font-face {
font-family: 'Smalle';
src: url("https://files.catbox.moe/x368w4.ttf");
}
.main {
position: absolute;
width: 650px;
height: 675px;
top: 50%;
left: 50%;
margin-top: -325px;
margin-left: -350px;
border: 3px dashed #456655;
background-color: #fff8e5;
font-family: 'Smalle';
}
.sidebar {
position: relative;
height: 675px;
width: 200px;
float: right;
background-color: #FEDA6A;
}
.sidecontent {
text-align: center;
font-family: 'Smalle';
}
.content {
margin-top: 10px;
}<html>
<head>
<meta charset="utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1" />
<title>TITLE</title>
<link href="1styles.css" rel="stylesheet" />
<style>
</style>
</head>
<body>
<div class="main">
<div class="sidebar">
<br>
<div class="sidecontent">
<p>This is where text and links will go... eventually.</p>
</div>
</div>
<div class="content">
<center><span class="title">TITLE</span></center>
<p style="padding: 5px; margin: 6px; width: 425px;">Lorem ipsum dolor sit amet...</p>
</div>
</div>
</body>
</html>您可以使用flexbox做类似的事情。在父元素上放置大纲，并使用负边距移动子元素以覆盖大纲。
.page-wrapper {
margin: 15px;
}
.row {
display: flex;
flex-direction: row;
flex-wrap: wrap;
width: 100%;
height: 400px;
outline: 5px dashed green;
}
.column {
display: flex;
flex-direction: column;
flex-basis: 100%;
flex: 1;
align-items: stretch;
background-color: red;
margin: -5px;
padding: 10px;
}
.column.left {
border-right: 0px;
}
.column.right {
border-left: 0px;
background-color: yellow;
}<div class='page-wrapper'>
<div class='row'>
<div class='column left'>
Column 1
</div>
<div class='column right'>
Column Two
</div>
</div>
</div>试试这个，这是你想要达到的效果吗?
body {
background-image: url("https://i.lensdump.com/i/Rxu5rz.png");
}
@font-face {
font-family: 'Smalle';
src: url("https://files.catbox.moe/x368w4.ttf");
}
.main {
position: absolute;
width: 650px;
height: 675px;
top: 50%;
left: 50%;
margin-top: -325px;
margin-left: -350px;
border: 3px dashed #456655;
background-color: #fff8e5;
font-family: 'Smalle';
}
.sidebar {
position: relative;
height: 681px;
width: 200px;
float: right;
background-color: #FEDA6A;
top: -3px;
right: -3px;
}
.sidecontent {
text-align: center;
font-family: 'Smalle';
}
.content {
margin-top: 10px;
}<html>
<head>
<meta charset="utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1" />
<title>TITLE</title>
<link href="1styles.css" rel="stylesheet" />
<style>
</style>
</head>
<body>
<div class="main">
<div class="sidebar">
<br>
<div class="sidecontent">
<p>This is where text and links will go... eventually.</p>
</div>
</div>
<div class="content">
<center><span class="title">TITLE</span></center>
<p style="padding: 5px; margin: 6px; width: 425px;">Lorem ipsum dolor sit amet...</p>
</div>
</div>
</body>
</html>