*{
box-sizing:border-box;
}

body{
margin:0;
font-family:"Microsoft YaHei",Arial;
background:#f5f6fa;
color:#222;
}

.layout{
display:flex;
height:100vh;
}

.sidebar{
width:230px;
background:#1e2330;
color:white;
padding:20px;
}

.menu a{
display:block;
padding:12px;
color:#ddd;
cursor:pointer;
text-decoration:none;
}

.menu a:hover{
background:#2a3142;
}

.content{
flex:1;
padding:30px;
}

.cards{
display:grid;
grid-template-columns:repeat(auto-fit,minmax(220px,1fr));
gap:20px;
}

.link-card{
background:white;
border:1px solid #ddd;
border-radius:12px;
padding:25px;
cursor:pointer;
}

.link-card:hover{
box-shadow:0 5px 15px rgba(0,0,0,.08);
}

h1{
font-size:24px;
}