* { box-sizing: border-box; }

body {
    margin: 0;
    font-family: Arial, sans-serif;
    background: #f4f6f8;
    color: #1c2530;
}

.topbar {
    height: 60px;
    padding: 18px 24px;
    background: #101820;
    color: #fff;
}

.app-shell {
    display: flex;
    min-height: calc(100vh - 60px);
}

.sidebar {
    width: 230px;
    padding: 20px 12px;
    background: #17212b;
}

.sidebar a {
    display: block;
    padding: 11px 14px;
    margin-bottom: 4px;
    color: #dbe3ea;
    text-decoration: none;
    border-radius: 6px;
}

.sidebar a:hover {
    background: #243343;
}

.main-content {
    flex: 1;
    padding: 28px;
}

.cards {
    display: grid;
    grid-template-columns: repeat(4, minmax(180px, 1fr));
    gap: 16px;
}

.card {
    padding: 18px;
    background: #fff;
    border-radius: 10px;
    box-shadow: 0 1px 5px rgba(0,0,0,.08);
}

.card span {
    display: block;
    margin-bottom: 8px;
}

.card strong {
    font-size: 28px;
}