header("Content-Type: text/html; charset=utf-8");
?>
<div class= 'r3243432'>
<div class = 'weeww'>
<div class = 'weeww'><a href='index.php'>贴吧首页a> div>
<a href="index.php" title="贴吧主页"><img src="/image/tieba_logo_117_38.png"style=" padding: -40px;width:102px; height:32px;margin-left:20px;margin-top:10px;">a>
<form action="search.php" method="post">
<input type="text" name="contexts" style="width:535px; height:40px; line-height:0px; margin-left:150px; margin-top:-110px;" class='hdi'/>
<font color="#FFFFFF";><input type="submit" name="enter" value="进入贴吧" class="btn-global"style="width:108px; height:40px; vertical-align:bottom;margin-left:-10px;" >font>
<font color="#000000";><input type="submit" name="search" value="全吧搜索"class = "i-ask-link"style="width:108px; height:40px;margin-top:-40px; vertical-align:bottom;" >font>
form>
<br/>
div>
<br/>
<style>
.r3243432 {
background-color: #fff;
-webkit-box-shadow: 0 2px 10px 0 rgb(0 0 0 / 10%);
box-shadow: 0 2px 10px 0 rgb(0 0 0 / 10%);
}
.hdi {
font-size: 16px;
width: 437px;
height: 40px;
border: 2px solid #C4C7CE;
border-radius: 10px;
border-bottom-color: #ccc;
border-radius: 10px 0 0 10px;
margin-top:-100px;
text-indent: 16px;
color: #222;
}
.btn-global {
font-family: Helvetica;
width: 112px;
height: 40px;
line-height: 40px;
font-size: 15px;
font-weight: 400;
border-radius: 0 10px 10px 0;
color: #fff;
background: #4E6EF2;
border: 0;
cursor:pointer;
}
.i-ask-link {
width: 112px;
height: 40px;
font-size: 15px;
font-family: Helvetica;
margin-left: 17px;
width: 108px;
height: 36px;
text-align: center;
line-height: 36px;
border: 2px solid #4E6EF2;
border-radius: 10px;
background: #FFFFFF;
color:#4E6EF2;
}
style>
你现在设置margin-top的元素父级是form，它本身的文档流就到那里了，现在是有效果的，只是没有100px的空间了，所以只移了不到100px的空间，
你如果想要和最左边对齐，可以给form标签加这个属性
标签上的对齐方式建议你用flex布局，万能