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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
    background: #f5f5f5;
    color: #222;
    min-height: 100vh;
    display: grid;
    place-items: center;
    padding: 2rem;
}

main {
    background: white;
    padding: 2.5rem;
    border-radius: 12px;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.08);
    max-width: 480px;
    width: 100%;
    text-align: center;
}

h1 {
    margin-bottom: 1rem;
    color: #1a1a1a;
}

p {
    margin-bottom: 1.5rem;
    color: #555;
}

button {
    background: #2563eb;
    color: white;
    border: none;
    padding: 0.75rem 1.5rem;
    border-radius: 8px;
    font-size: 1rem;
    cursor: pointer;
    transition: background 0.2s;
}

button:hover {
    background: #1d4ed8;
}

#output {
    margin-top: 1rem;
    min-height: 1.5rem;
    color: #2563eb;
    font-weight: 500;
}