body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: #f5f5f5;
    color: #333;
    line-height: 1.6;
    min-height: 100vh;
    padding: 20px;
}

.centered {
    display: flex;
    justify-content: center;
    align-items: center;
}

.vstack {
    display: flex;
    flex-direction: column;
}

.hstack {
    display: flex;
    flex-direction: row;
}