* {
    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;
}

.main {
    flex-grow: 1;
    padding: 2rem;
}

.cards {
    display: grid;
    grid-template-columns: repeat(3, 1fr); /*fraction*/
    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; /*8px*/
}
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;
}