*
{
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: Arial, Helvetica, sans-serif;
}

body 
{
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 100vh;
    background: #e3f2fd;
}

.wrapper
{
    width: 780px;
    border-radius:20px;
    padding: 35px 40px;
    background: #141414;
}

.wrapper header
{
    color: #b2b2b2;
    display: flex;
    align-items: center;
    justify-content: center;
}

header h2
{
    font-size: 1.6rem;
}

header .column 
{
    display: flex;
    align-items: center;
}

header .column span
{
    font-weight: 500;
    margin-left: 15px;
    font-size: 1.19rem;
}

.volume-slider input
{
    accent-color: #fff;
    outline: none;
}

.keys-checkbox input 
{
    outline: none;
    width: 60px;
    height: 30px;
    cursor: pointer;
    appearance: none;
    border-radius: 30px;
    background: #4b4b4b;
    position: relative;
    margin-left: 20px;
}

.keys-checkbox input::before
{
    content: "";
    height: 20px;
    width: 20px;
    top: 50%;
    left: 5px;
    border-radius: inherit;
    position: absolute;
    background: #8c8c8c;
    transform: translateY(-50%);
    transition: all 0.3s ease;
}

.keys-checkbox input:checked::before
{
    position: absolute;
    left: 35px;
    background: #fff;
}

.piano-keys
{
    display: flex;
    margin-top: 40px;
}

.piano-keys .key{
    cursor: pointer;
    list-style: none;
    color: #a2a2a2;
    position: relative;
    text-transform: uppercase;
    user-select: none;
}

.piano-keys .black
{
    width: 44px;
    height: 140px;z-index: 2;
    margin: 0 -22px 0 -22px;
    border-radius: 0 0 5px 5px;
    background: linear-gradient(#333 , #000);
}

.piano-keys .black.active 
{   
    box-shadow: inset -5px 5px 10px rgba(255 , 255 , 255 , 0.1);
    background: linear-gradient(to bottom , #000, #434343);
}

.piano-keys .white
{
    width: 70px;
    height: 230px;
    border-radius: 8px;
    border: 1px solid #000;
    background: linear-gradient(#fff 96% , #eee 4%);
}

.piano-keys .white.active 
{   
    box-shadow: inset -5px 5px 20px rgba(0,0,0,0.2);
    background: linear-gradient(to bottom , #fff 0% , #eee 100%);
}

.piano-keys span
{
    position: absolute;
    bottom: 20px;
    width: 100%;
    text-align: center;
    font-size: 1.13rem;
}

.piano-keys .key.hide span 
{
    display: none;
}