*{
    font-family:"Noto Sans JP",sans-serif;
}
.marker {
    color:rgb(255, 51, 0);
    background-image:linear-gradient(#f8e3b6,#f8e3b6);
    background-repeat:no-repeat;
    background-position:left;
    background-size:0% 100%;
    transition:background-size 0.8s ease;
    margin:0 3px;
}
.marker.is-active{
    background-size:100% 100%;
}