// @grant GM_addStyle
// @match https://chat.meta.stackexchange.com/*
// @match http://chat.meta.stackexchange.com/*
// @match https://chat.stackexchange.com/*
// @match http://chat.stackexchange.com/*
// ==/UserScript==
GM_addStyle("\
.spoiler, .spoiler > * { transition: color 0.5s; opacity: 0.5s; min-height:25px; }\
.spoiler:not(:hover) { color: transparent }\
.spoiler:not(:hover) > * { opacity: 0 }\
.spoiler:not(:hover)::before { \
content: 'SPOILER'; \
position: absolute; \