Welcome-section id的所有属性都能正常工作。当我将同样的属性应用于另一个id，project1时，margin属性完全不起作用。请指导我做错了什么。
#main {}
#project1 {
background-color: rgba(235, 232, 223, 1);
margin-top: 1000px;
height: 2500px;
}
#welcome-section {
background-color: rgba(214, 210, 197, 0.7);
margin: 25px 25px 25px 25px;
text-align: center;
height: 50px;
font-family: "Lucida Sans Unicode", "Lucida Grande", sans-serif;
vertical-align: middle;
display: table-cell;
width: 850px;
font-size: 120%;
font-weight: bold;
color: ;
border-style: dotted;
border-color: blue;
text-shadow: 2px 2px 5px powderblue;
}<body id='main'>
<header>
<navbar id='nav-bar'></navbar><br>
<h1 id='welcome-section'>
How can I help your business grow?</h1>
</header>
<br>
<projects id='projects'>
<project1 id='project1'>
<projectt id='prjctt'>Desalination in Balochistan</projectt>
<proimg id='proimg'></proimg>
</project1>
</projects>
</body>你可以在这里看到它。
在你的css中添加display:flex
#project1 {
background-color: rgba(235, 232, 223, 1);
margin-top: 1000px;
height: 2500px;
display:flex;
}