body {
    font-family: sans-serif;
    display: flex;
    flex-direction: column; /* Ensure items stack vertically */
    justify-content: center; /* This will center the block of container+footer */
    align-items: center; /* Center items horizontally */
    min-height: 100vh;
    margin: 0;
    background-color: #f0f0f0;
    color: #333;
}

.container {
    text-align: center;
    background-color: #fff;
    padding: 20px;
    border-radius: 8px;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
}

.controls {
    margin-bottom: 20px;
}

.controls label {
    margin-right: 10px;
}

#harmonic-canvas {
    border: 1px solid #ccc;
    cursor: pointer;
    margin-bottom: 20px;
    /* Ensure canvas is not larger than its container or viewport */
    max-width: 100%;
    height: auto; /* Maintain aspect ratio if width is constrained */
}

/* Remove .key styles as they are no longer used */

p {
    font-size: 0.9em;
    color: #666;
}

footer {
    margin-top: 30px;
    padding-top: 15px;
    border-top: 1px solid #eee; /* Use hr in html or border-top in css */
    font-size: 0.8em;
    color: #777;
    text-align: center;
}

footer p {
    margin: 5px 0;
    font-size: 1em; /* Relative to footer's font-size */
}