body {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 20px;
}

.buttons {
    display: flex;
    align-items: center;
    gap: 20px;
}

input {
    text-align: center;
    font-size: 20px;
    border: none;
}

input:focus {
    outline: none;
    border: none;
}

button {
    font-size: 20px;
    padding: 5px;
}

table {
    border-collapse: collapse;
}

td {
    border: 1px solid black;
    text-align: center;
    width: 40px;
    height: 40px;
}

.thick-right {
    border-right: 3px solid black;
}

.thick-bottom {
    border-bottom: 3px solid black;
}

ul {
    max-width: 40%;
    font-family: Arial, Helvetica, sans-serif;
}

li {
    padding: 2px;
}