body { font-family: sans-serif; padding: 1rem; }
.tape { display: flex; overflow-x: auto; margin-bottom: 1rem; }
.cell {
    border: 1px solid #ccc;
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    user-select: none;
}
.head { border: 2px solid #000; background: #eef; }
table { width: 100%; border-collapse: collapse; margin-top: 1rem; }
th, td { border: 1px solid #ccc; padding: 0.5rem; text-align: center; }
button { margin: 0.5rem 0.2rem; }