body {
    background-color: white;
    margin-top: 100px;
}

.panel {
    width: 150px;
    height: 150px;
    display: inline-block;
    cursor: pointer;

}

.panel:hover {
    /*border: 1px solid red ;*/
    box-shadow: 0px 0px 10px cyan;
    box-sizing: border-box;
}

.bottom-right-panel {
    background-color: red;
    border-bottom-right-radius: 100%;

}

.bottom-left-panel {
    background-color: blue;
    border-bottom-left-radius: 100%;

}

.top-right-panel {
    background-color: green;
    border-top-right-radius: 100%;

}

.top-left-panel {
    background-color: yellow;
    border-top-left-radius: 100%;

}

.active {
    background-color: white;
}

.center {
    display: inline-block;
    position: absolute;
    width: 150px;
    height: 150px;
    border-radius: 100%;
    background-color: white;
    top: 235px;
    left: 85px;
}

#game-over-screen {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.8);
    display: flex;
    align-items: center;
    justify-content: center;
    flex-direction: column;
    color: white;
    font-size: 36px;
}

#game-over-screen.hidden {
    display: none;
}

#hearts img {
    display: inline-block;
    margin-right: 5px;
    width: 100px;
    height: 100px;
}