html, body {
    margin: 0;
    font-family: Arial, Helvetica, sans-serif;
    background: #f4f6f8;
    color: #1f2937;
}

.page-shell {
    display: grid;
    grid-template-columns: 260px 1fr;
    min-height: 100vh;
}

.sidebar {
    background: #0f172a;
    color: white;
    padding: 24px;
}

.sidebar h2 {
    margin-top: 0;
    font-size: 1.25rem;
}

.sidebar nav {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.sidebar a {
    color: #dbeafe;
    text-decoration: none;
    padding: 10px 12px;
    border-radius: 10px;
}

.sidebar a:hover {
    background: rgba(255,255,255,0.08);
}

.content {
    padding: 24px;
}

.card-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 16px;
}

.card {
    background: white;
    border-radius: 16px;
    padding: 18px;
    box-shadow: 0 4px 14px rgba(0,0,0,0.08);
}