Roblox Black and Gray play button by staircase

/* ==UserStyle==
@name           Roblox Black and White button
@namespace      USO Archive
@author         TheMetalEngine 20
@description    `This changes the Black (White if dark mode, green if have Roblox in 2016) play button to blue and green`
@version        20210912.22.4
@license        CC0-1.0
@preprocessor   uso
==/UserStyle== */
@-moz-document domain("roblox.com") {
@keyframes rainbow {
    0% {
        background-color: #292929;
        border-color: #c0c0c0;
    }
    14% {
        background-color: #c0c0c0;
        border-color: #292929;
    }
    28% {
        background-color: #292929;
        border-color: #c0c0c0;
    }
    42% {
        background-color: #c0c0c0;
        border-color: #292929;
    }
    56% {
        background-color: #292929;
        border-color: #c0c0c0;
    }
    80% {
        background-color: #c0c0c0;
        border-color: #292929;
    }
    94% {
        background-color: #292929;
        border-color: #c0c0c0;
    }
    100% {
        background-color: #c0c0c0;
        border-color: #292929;
    }
}
.btn-common-play-game-lg {
    animation: rainbow 10s infinite;
}
}