Add rainbow function for MFM

src/client/components/global/misskey-flavored-markdown.vue

@@ -117,6 +117,11 @@ export default defineComponent({
 	75% { transform: scale3d(1.05, 0.95, 1); }
 	to { transform: scale3d(1, 1, 1); }
 }
+
+@keyframes mfm-rainbow {
+	0% { filter: hue-rotate(0deg) contrast(150%) saturate(150%); }
+	100% { filter: hue-rotate(360deg) contrast(150%) saturate(150%); }
+}
 </style>
 
 <style lang="scss" scoped>

src/client/components/mfm.ts

@@ -165,6 +165,10 @@ export default defineComponent({
 								class: '_mfm_blur_',
 							}, genEl(token.children));
 						}
+						case 'rainbow': {
+							style = this.$store.state.animatedMfm ? 'animation: mfm-rainbow 1s linear infinite;' : '';
+							break;
+						}
 					}
 					if (style == null) {
 						return h('span', {}, ['[', token.props.name, ...genEl(token.children), ']']);