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

body {
    font-family:
        -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue",
        Arial, sans-serif;
    background: #ffffff;
    min-height: 100vh;
    padding: 2rem;
    display: flex;
    flex-direction: column;
    align-items: center;
}

header {
    text-align: center;
    color: #0f172a;
    margin-bottom: 1.5rem;
}

h1 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
    letter-spacing: -1px;
}

.author {
    font-size: 1.1rem;
    font-weight: 400;
    opacity: 0.75;
}

.top-row {
    width: 100%;
    max-width: 1200px;
    margin-bottom: 1rem;
}

.main-content {
    display: flex;
    width: 100%;
    max-width: 1200px;
}

#counter {
    width: fit-content;
    min-width: 200px;
    background: #f8fafc;
    padding: 0.85rem 1rem;
    border-radius: 8px;
    border: 1px solid #e2e8f0;
    font-size: 1rem;
    font-weight: 600;
    color: #0f172a;
    text-align: center;
}

#container {
    width: 100%;
    background: #ffffff;
    border-radius: 8px;
    padding: 1.5rem;
    border: 1px solid #e2e8f0;
    overflow-y: auto;
    max-height: 70vh;
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(24px, 1fr));
    gap: 0.6rem;
}

input[type="checkbox"] {
    width: 22px;
    height: 22px;
    cursor: pointer;
    accent-color: #0f172a;
}

input[type="checkbox"]:hover {
    accent-color: #2563eb;
}

@media (max-width: 640px) {
    body {
        padding: 1rem;
    }

    h1 {
        font-size: 2rem;
    }

    #container {
        padding: 1rem;
        grid-template-columns: repeat(auto-fill, minmax(28px, 1fr));
        gap: 0.5rem;
    }
}