main只设置width, min_height, content不设置float, sidebar设置float:right,两栏不设置高度

cnodejs_两栏布局.css

/* base */
body,p {
  font-size: 12px;
  line-height: 16px;
  font-family: "Helvetica Neue", Helvetica, Arial, sans-serif;
  word-break: break-all;
}

#wrapper {
  background: #d0d6db;
}
#main {
  width: 960px;
  margin: 0px auto;
  padding: 10px 0px 30px 0px;
  min-height:400px;
}
#content {
  margin: 0px 272px 0px 0px;
  padding: 10px 10px 0px 0px;
}
#sidebar {
  width: 272px;
  padding: 10px 0px 10px 10px;
  float: right;
}
#footer {
  height:200px;
  clear: both;
}
#footer_main {
  width:920px;
  margin: 0px auto;
  color:#e2e2e2;
  padding:20px 0px;
}