.heart {
    fill: red;
    top: 15px;
    left: 15px;
    width: 30px;
    position: absolute;
    opacity: .1;
}

.pin {
    fill: blue;
    top: 55px;
    left: 15px;
    width: 30px;
    position: absolute;
    opacity: .1;
}

.heart.toggling {
    animation: pulse .3s ease 2;
}

.pin.toggling {
    animation: pin .75s ease 1;
}

.isInList {
    opacity: 1;
}

@keyframes pulse {
    0% { transform: scale(1); }
    50% { transform: scale(1.1); }
    100% { transform: scale(1); }
}

@keyframes pin {
    0%   {opacity: .1; transform: scale(1);}
    50%  {opacity: .5; transform: scale(1.2);}
    100% {opacity: 1; transform: scale(1);}
}