Rainbow play button for Roblox by crax

/* ==UserStyle==
@name           Rainbow play button for Roblox
@namespace      USO Archive
@author         CraX_e621
@description    `Just makes the play button on games glow through a rainbow of colours. Speed can be changed.You may also like: https://userstyles.org/styles/176973/hello-roblox`
@version        20191107.2.11
@license        CC-BY-NC-SA-4.0
@preprocessor   uso
@advanced text speed "Speed (in seconds)" "10"

==/UserStyle== */
@-moz-document domain("roblox.com") {
@keyframes rainbow {
    0% {background-color: red;border-color: red;}
    14% {background-color: orange;border-color: orange;}
    28% {background-color: yellow;border-color: yellow;}
    42% {background-color: green;border-color: green;}
    56% {background-color: cyan;border-color: cyan;}
    80% {background-color: blue;border-color: blue;}
    94% {background-color: deeppink;border-color: deeppink;}
    100% {background-color: red;border-color: red;}
}

a.btn-common-play-game-lg {
    animation: rainbow /*[[speed]]*/s infinite;
}
}