* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: Arial;
  display: flex;
  min-height: 100vh; /*1vh=1/100 chieu caoview*/
  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(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;
}