all: sync with master; upd chlog

client/src/helpers/constants.js

@@ -227,6 +227,14 @@ export const BLOCKING_MODES = {
     custom_ip: 'custom_ip',
 };
 
+// Note that translation strings contain these modes (theme_CONSTANT)
+// i.e. theme_auto, theme_light.
+export const THEMES = {
+    auto: 'auto',
+    dark: 'dark',
+    light: 'light',
+};
+
 export const WHOIS_ICONS = {
     location: 'location',
     orgname: 'network',

client/src/helpers/helpers.js

@@ -670,6 +670,15 @@ export const setHtmlLangAttr = (language) => {
     window.document.documentElement.lang = language;
 };
 
+/**
+ * Sets UI theme.
+ *
+ * @param theme
+ */
+export const setUITheme = (theme) => {
+    document.body.dataset.theme = theme;
+};
+
 /**
  * @param values {object}
  * @returns {object}