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

body {
  font-family: Arial, sans-serif;
  background-color: #f2f2f2;
  display: grid;
  grid-template-columns: 70% 30%;
  max-width: 1200px;
  margin: 0 auto;
}

/* Header */
header {
  background-color: #c7cc19;
  color: #fff;
  padding: 20px;
  text-align: center;
  grid-column: 1 / span 2;
}

/* Menu */
nav {
  background-color: #ffa486;
  color: #fff;
  text-align: center;
  padding: 10px;
  grid-column: 1 / span 2;
}
nav ul { list-style: none; }
nav ul li { display: inline; margin-right: 20px; }

/* Sản phẩm */
.product-list {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
  padding: 20px;
  grid-column: 1;
}
.product-card {
  background: #fff;
  border: 1px solid #ddd;
  border-radius: 5px;
  text-align: center;
  padding: 10px;
}
.product-card img { max-width: 100%; }

/* Sidebar */
.sidebar {
  background-color: #1975ff;
  color: #fff;
  padding: 10px;
  grid-column: 2;
}
.social-icons a {
  color: #fff;
  text-decoration: none;
  display: block;
  margin-bottom: 10px;
}

/* Footer */
.footer {
  background-color: #333;
  color: #fff;
  padding: 20px;
  grid-column: 1 / span 2;
  display: grid;
}
.footer-item { padding: 10px; }

/* Responsive */
@media (max-width: 576px) {
  .product-list { grid-template-columns: 1fr; }
  .sidebar { grid-column: 1 / span 2; }
  .footer { grid-template-columns: 1fr; }
}
@media (min-width: 768px) {
  .footer { grid-template-columns: repeat(3, 1fr); }
}

/* Button */
.button {
  background-color: #00ff88;
  border: none;
  color: white;
  padding: 10px 20px;
  text-align: center;
  display: inline-block;
  font-size: 16px;
  margin: 4px 2px;
}
.button4 { border-radius: 12px; }