body {
    font-family: system-ui, sans-serif;
    max-width: 760px;
    margin: 2rem auto;
    padding: 0 1rem;
    color: #222;
}

header a {
    font-weight: bold;
    text-decoration: none;
    color: #222;
}

ul {
    padding-left: 1.2rem;
}

form {
    display: flex;
    gap: 0.5rem;
    margin: 1rem 0;
}

input[type=text],
input[type=number] {
    padding: 0.4rem;
    flex: 1;
}

button {
    padding: 0.4rem 0.8rem;
}

.result {
    border: 1px solid #ddd;
    border-radius: 6px;
    padding: 0.6rem 0.8rem;
    margin: 0.5rem 0;
}

.result .score {
    color: #888;
    font-size: 0.85em;
}

.error {
    color: #b00;
}

mark {
    background: #ffe58a;
}