*{
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}
body {
font-family: Arial, Helvetica, sans-serif;
display:flex;
min-height: 100vh;/*1vh = 1/100 chieu cao view*/
background: #f4f4f4;
}
.leftbar{
    width: 250px;
    background-color: #2c3e50;
    color: white;
    padding:1rem;
}
.leftbar h2{
    margin-bottom: 2rem;
}
.leftbar a{
    display:block;
    color:white;
    text-decoration: none;
    margin-bottom: 1rem;
}
.leftbar a:hover{
    text-decoration: underline;
}
.main{
    flex-grow: 1;
    padding:2rem;
}
.card{
    display: grid;
    grid-template-columns: repeat(auto-fit,minmax(200px,1fr));
    gap:1rem;
}
.card{
    background:white;
    padding: 1.5rem;
    border-radius: 8px;
    box-shadow: 0 0 10px rgba(0,0,0,0.1);
}
.card h3{
    margin-bottom: 0.5rem;
}
table{
    width: 100%;
    border-collapse: collapse;
    margin-top: 2rem;
}
table th,table td{
    padding: 0.75rem;
    text-align: left;
    border-bottom: 1px solid #ccc;
}
table th{
    background-color: #ecf0f1;
}