body {
    font-family: Arial, sans-serif;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    margin: 0;
    background-color: #f0f0f0;
}

.container {
    text-align: center;
    background-color: white;
    padding: 20px;
    border-radius: 10px;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
}

h1 {
    color: #333;
    margin-bottom: 20px;
}

.controls {
    margin-bottom: 20px;
}

button {
    padding: 10px 15px;
    margin: 0 5px;
    border: none;
    border-radius: 5px;
    background-color: #4CAF50;
    color: white;
    cursor: pointer;
    font-size: 16px;
}

button:hover {
    background-color: #45a049;
}

select {
    padding: 10px;
    font-size: 16px;
    border-radius: 5px;
}

.game-info {
    display: flex;
    justify-content: space-between;
    margin-bottom: 20px;
    font-size: 18px;
    font-weight: bold;
}

#kenken-grid {
    display: inline-block;
    margin: 20px auto;
}

.kenken-table {
    border-collapse: collapse;
    margin: 0 auto;
}

.kenken-table td {
    width: 50px;
    height: 50px;
    text-align: center;
    vertical-align: middle;
    border: 1px solid #333;
    position: relative;
    font-size: 20px;
    font-weight: bold;
}

.kenken-table td input {
    width: 100%;
    height: 100%;
    border: none;
    text-align: center;
    font-size: 20px;
    font-weight: bold;
    background-color: transparent;
    outline: none;
}

.kenken-table td.top-border {
    border-top: 3px solid #333;
}

.kenken-table td.right-border {
    border-right: 3px solid #333;
}

.kenken-table td.bottom-border {
    border-bottom: 3px solid #333;
}

.kenken-table td.left-border {
    border-left: 3px solid #333;
}

.cage-label {
    position: absolute;
    top: 2px;
    left: 2px;
    font-size: 12px;
    font-weight: normal;
}

#message {
    margin-top: 20px;
    font-size: 18px;
    font-weight: bold;
    min-height: 25px;
}

.success {
    color: green;
}

.error {
    color: red;
}

.highlight {
    background-color: #ffffcc;
}