Better automatic dark mode (#1069)

benediktwerner · Dylan-DPC · commit c9dae170f38b · 2019-10-23T12:15:59.000+02:00
* Don't save default theme to localStorage

* Auto enable dark mode on no-js

* Fix light theme with no-js
diff --git a/src/theme/book.js b/src/theme/book.js
@@ -296,7 +296,7 @@ function playpen_text(playpen) {
         themeToggleButton.focus();
     }
 
-    function set_theme(theme) {
+    function set_theme(theme, store = true) {
         let ace_theme;
 
         if (theme == 'coal' || theme == 'navy') {
@@ -331,9 +331,10 @@ function playpen_text(playpen) {
         try { previousTheme = localStorage.getItem('mdbook-theme'); } catch (e) { }
         if (previousTheme === null || previousTheme === undefined) { previousTheme = default_theme; }
 
-        try { localStorage.setItem('mdbook-theme', theme); } catch (e) { }
+        if (store) {
+            try { localStorage.setItem('mdbook-theme', theme); } catch (e) { }
+        }
 
-        document.body.className = theme;
         html.classList.remove(previousTheme);
         html.classList.add(theme);
     }
@@ -343,7 +344,7 @@ function playpen_text(playpen) {
     try { theme = localStorage.getItem('mdbook-theme'); } catch(e) { }
     if (theme === null || theme === undefined) { theme = default_theme; }
 
-    set_theme(theme);
+    set_theme(theme, false);
 
     themeToggleButton.addEventListener('click', function () {
         if (themePopup.style.display === 'block') {
diff --git a/src/theme/css/variables.css b/src/theme/css/variables.css
@@ -208,3 +208,45 @@
     --searchresults-li-bg: #dec2a2;
     --search-mark-bg: #e69f67;
 }
+
+@media (prefers-color-scheme: dark) {
+    .light.no-js {
+        --bg: hsl(200, 7%, 8%);
+        --fg: #98a3ad;
+
+        --sidebar-bg: #292c2f;
+        --sidebar-fg: #a1adb8;
+        --sidebar-non-existant: #505254;
+        --sidebar-active: #3473ad;
+        --sidebar-spacer: #393939;
+
+        --scrollbar: var(--sidebar-fg);
+
+        --icons: #43484d;
+        --icons-hover: #b3c0cc;
+
+        --links: #2b79a2;
+
+        --inline-code-color: #c5c8c6;;
+
+        --theme-popup-bg: #141617;
+        --theme-popup-border: #43484d;
+        --theme-hover: #1f2124;
+
+        --quote-bg: hsl(234, 21%, 18%);
+        --quote-border: hsl(234, 21%, 23%);
+
+        --table-border-color: hsl(200, 7%, 13%);
+        --table-header-bg: hsl(200, 7%, 28%);
+        --table-alternate-bg: hsl(200, 7%, 11%);
+
+        --searchbar-border-color: #aaa;
+        --searchbar-bg: #b7b7b7;
+        --searchbar-fg: #000;
+        --searchbar-shadow-color: #aaa;
+        --searchresults-header-fg: #666;
+        --searchresults-border-color: #98a3ad;
+        --searchresults-li-bg: #2b2b2f;
+        --search-mark-bg: #355c7d;
+    }
+}
diff --git a/src/theme/index.hbs b/src/theme/index.hbs
@@ -1,5 +1,5 @@
 <!DOCTYPE HTML>
-<html lang="{{ language }}" class="sidebar-visible no-js">
+<html lang="{{ language }}" class="sidebar-visible no-js {{ default_theme }}">
     <head>
         <!-- Book generated using mdBook -->
         <meta charset="UTF-8">
@@ -39,7 +39,7 @@
         <script async type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.1/MathJax.js?config=TeX-AMS-MML_HTMLorMML"></script>
         {{/if}}
     </head>
-    <body class="{{ default_theme }}">
+    <body>
         <!-- Provide site root to javascript -->
         <script type="text/javascript">
             var path_to_root = "{{ path_to_root }}";
@@ -67,8 +67,11 @@
             var theme;
             try { theme = localStorage.getItem('mdbook-theme'); } catch(e) { }
             if (theme === null || theme === undefined) { theme = default_theme; }
-            document.body.className = theme;
-            document.querySelector('html').className = theme + ' js';
+            var html = document.querySelector('html');
+            html.classList.remove('no-js')
+            html.classList.remove('{{ default_theme }}')
+            html.classList.add(theme);
+            html.classList.add('js');
         </script>
 
         <!-- Hide / unhide sidebar before it is displayed -->
