generate a css code for following code: <!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Admin Dashboard - Beauty Salon</title>
<link rel="stylesheet" href="styles.css">
</head>
<body>
<header>
<div class="logo">Beauty Salon - Admin</div>
<nav>
<ul>
<li><a href="admin-dashboard.html">Dashboard</a></li>
<li><a href="admin-appointments.html">Appointments</a></li>
<li><a href="admin-products.html">Products</a></li>
<li><a href="index.html">Logout</a></li>
</ul>
</nav>
</header>
<main>
<section class="dashboard-container">
<h1>Admin Dashboard</h1>
<div class="stats-grid">
<div class="stat-card">
<h3>Today's Appointments</h3>
<p class="stat-number">12</p>
</div>
<div class="stat-card">
<h3>New Customers</h3>
<p class="stat-number">5</p>
</div>
<div class="stat-card">
<h3>Revenue</h3>
<p class="stat-number">$1,245</p>
</div>
<div class="stat-card">
<h3>Products Sold</h3>
<p class="stat-number">8</p>
</div>
</div>
</section>
</main>
<script src="script.js"></script>
</body>
</html>