*{
            margin: 0;
            padding: 0;
            box-sizing: border-box;
}body {
        font-family: Arial;
        display: flex;
        min-height: 100vh;/*1vh 1/100 chiều 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;
        color:plum;
        font-size: 1.1rem;
}
.main {
        flex-grow: 1;
        padding: 2rem;
}
            .cards {
                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 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;
            }