<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8" /> <meta http-equiv="X-UA-Compatible" content="IE=edge" /> <meta name="viewport" content="width=device-width, …
关于margin-top失效, 常出现两种情况： （一）兄弟元素之间margin-top失效 先看下面代码： <div> <div class="box1"> float: left </div> <div class="box2"> clear:both; margin-top:20px; </div> </div> 两个层box1和box2，box1具有浮动属性，box2没有，这时候设置box2的上边…
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8" /> <meta http-equiv="X-UA-Compatible" content="IE=edge" /> <meta name="viewport" content="width=device-width, …
// css html｛ -webkit-filter:grayscale(100%); -moz-filter:grayscale(100%); -ms-filter:grayscal(100%); -o-filter:grayscal(100%); filter:grayscale(100%); filter:gray; ｝