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

body {
    font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    background-color: #f9fafb;
    color: #111827;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 30px 15px 15px;
}

h1 {
    font-size: 28px;
    font-weight: 700;
    margin-bottom: 8px;
}

#status {
    font-size: 16px;
    color: #4b5563;
    margin-bottom: 16px;
}

#board {
    display: grid;
    gap: 4px;
    background-color: #e5e7eb;
    padding: 6px;
    border-radius: 8px;
}

.cell {
    width: 50px;
    height: 50px;
    font-size: 24px;
    font-weight: bold;
    cursor: pointer;
    background-color: #ffffff;
    border: 1px solid #d1d5db;
    border-radius: 4px;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: background-color 0.15s ease;
}

.cell:hover:not(.obstacle):not(:disabled) {
    background-color: #f3f4f6;
}

.cell.obstacle {
    background-color: #374151;
    border-color: #1f2937;
    cursor: not-allowed;
}

#restart {
    margin-top: 20px;
    padding: 9px 20px;
    font-size: 15px;
    font-weight: 500;
    color: #ffffff;
    background-color: #111827;
    border: none;
    border-radius: 6px;
    cursor: pointer;
    transition: background-color 0.15s ease;
}

#restart:hover {
    background-color: #374151;
}

footer {
    margin-top: auto;
    padding-top: 25px;
    font-size: 14px;
    color: #6b7280;
}

footer a {
    color: #111827;
    text-decoration: none;
    font-weight: 500;
}

footer a:hover {
    text-decoration: underline;
}