Fix the logo display

Author: ehsanmok

book/src/intro.md

@@ -1,11 +1,8 @@
 <div class="license-notice">
 <p><em>Materials in this book are distributed under the terms of <a href="https://github.com/ehsanmok/create-your-own-lang-with-rust/blob/master/LICENSE">Creative Commons BY-NC-SA 4.0</a></em></p>
 <img alt="license" src="./img/by-nc-sa.png">
-<picture>
-  <source media="(prefers-color-scheme: dark)" srcset="./img/logo_dark_mode.png">
-  <source media="(prefers-color-scheme: light)" srcset="./img/logo_light_mode.png">
-  <img src="./img/logo_dark_mode.png" alt="CreateLang.rs Logo" class="logo-img" width="320">
-</picture>
+<img src="./img/logo_light_mode.png" alt="CreateLang.rs Logo" class="logo-img logo-light" width="320">
+<img src="./img/logo_dark_mode.png" alt="CreateLang.rs Logo" class="logo-img logo-dark" width="320">
 </div>
 
 ---

book/theme/custom.css

@@ -383,6 +383,38 @@ blockquote p {
   height: auto;
 }
 
+/* =============================================================================
+   LOGO THEME SWITCHING
+   Show correct logo based on mdbook theme, not OS prefers-color-scheme
+   ============================================================================= */
+
+.license-notice .logo-img {
+  max-width: 320px;
+  height: auto;
+}
+
+/* Default: show light mode logo (for Rust theme - light background) */
+.license-notice .logo-light {
+  display: block;
+}
+
+.license-notice .logo-dark {
+  display: none;
+}
+
+/* Dark themes: show dark mode logo (light text for dark backgrounds) */
+.coal .license-notice .logo-light,
+.navy .license-notice .logo-light,
+.ayu .license-notice .logo-light {
+  display: none;
+}
+
+.coal .license-notice .logo-dark,
+.navy .license-notice .logo-dark,
+.ayu .license-notice .logo-dark {
+  display: block;
+}
+
 /* =============================================================================
    LINKS
    ============================================================================= */