body { margin: 20px; font-family: Arial; }
#output { margin: 20px 0; }
.stats { margin: 20px 0; font-size: 18px; }
.piano-container { position: relative; margin: 20px 0; }
.piano-keys-list { 
    list-style: none; 
    padding: 0; 
    margin: 0; 
    display: flex; 
    position: relative; 
}
.piano-keys {
    cursor: pointer;
    position: relative;
    height: 150px;
    border-radius: 10px;
    border: 1px solid #000;
    transition: background-color 0.3s ease;
}
.white-key {
    background-color: #fff;
    width: 50px;
}
.black-key {
    width: 30px;
    height: 90px;
    border-radius: 5px;
    border-top-left-radius: 0;
    border-top-right-radius: 0;
    background-color: #000;
    z-index: 2;
    margin: 0 -15px 0 -15px;
}
        
@media screen and (max-width: 576px) {
    .piano-container {
        width: 90%;
        display: flex;
        align-items: center;
        justify-content: flex-start;
        overflow: auto;
    }

    .piano-keys {
        width: 3.5rem;
        cursor: pointer;
        position: relative;
        height: 16rem;
        border-radius: 10px;
        border: 1px solid #000;
    }

    .black-key {
        width: 1.8rem;
        height: 10rem;
        border-radius: 5px;
        border-top-left-radius: 0;
        border-top-right-radius: 0;
        background-color: #000;
        z-index: 2;
        margin: 0 -20px 0 -20px;
    }
}

.piano-keys {
    position: relative;
    text-align: center;
    font-size: 12px;
    font-weight: bold;
    color: #000;
}
.white-key {
    color: #000;
    padding-top: 120px;
}
.black-key {
    color: #fff;
    padding-top: 60px;
    text-shadow: 0 0 2px #000;
}
.piano-keys-list {
    user-select: none;
}