body {
    font-family: Arial, sans-serif;
    text-align: center;
}
table {
    margin: 20px auto;
    border-collapse: collapse;
}
td {
    width: 40px;
    height: 40px;
    border: 1px solid #aaa;
    text-align: center;
    vertical-align: middle;
    font-size: 18px;
}
.marcado {
    background-color: gold;
    font-weight: bold;
    color: darkred;
}
.ultimo {
    border: 2px solid red;
}
form {
    margin: 20px;
}
button {
    padding: 10px 20px;
    font-size: 16px;
}