body {
    font-family: sans-serif;
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 20px;
    background-color: #f4f4f4;
}

#puzzleCanvas {
    border: 3px solid #333;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.2);
    margin: 20px 0;
}

#controls {
    margin-top: 20px;
    padding: 15px;
    border: 1px solid #ccc;
    border-radius: 8px;
    background-color: white;
    text-align: center;
}

#controls button {
    padding: 10px 15px;
    margin: 5px;
    font-size: 16px;
    cursor: pointer;
    border: none;
    border-radius: 5px;
    transition: background-color 0.2s;
}

#btn-reverse { background-color: #007bff; color: white; }
#btn-channel-shift { background-color: #28a745; color: white; }
#btn-invert { background-color: #ffc107; }
#btn-reset { background-color: #dc3545; color: white; }

#game-message {
    margin-top: 20px;
    font-weight: bold;
    min-height: 20px; /* To prevent layout shift */
}

/* Class to visually hide the memory hint after a delay */
.hidden {
    display: none;
}