feat: coloration syntaxique via CSS classes (themeable)

Remplace les styles inline syntect par des classes CSS. Le CSS est
généré côté Rust (base16-ocean.dark) et injecté au démarrage via
get_syntax_highlight_css. Les thèmes peuvent surcharger .syntax-highlighting
et les classes de tokens. Supprime le lien CDN highlight.js inutilisé.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src-tauri/resources/themes/default.css

@@ -98,15 +98,21 @@ body {
   border: 1px solid #e2e8f0;
 }
 
-/* Bloc de code (entre triple backticks) */
-.content pre {
+/* Bloc de code sans coloration syntaxique */
+.content pre:not(.syntax-highlighting) {
   background: #0f172a;
   border: 1px solid #1e293b;
   border-radius: 10px;
 }
 
-/* Texte à l'intérieur d'un bloc de code */
-.content pre code {
+/* Bloc de code avec coloration syntaxique */
+.content .syntax-highlighting {
+  border: 1px solid #1e293b;
+  border-radius: 10px;
+}
+
+/* Texte dans un bloc sans coloration */
+.content pre:not(.syntax-highlighting) code {
   background: none;
   color: #e2e8f0;
 }

src-tauri/resources/themes/shell-indigo.css

@@ -9,8 +9,9 @@ body { background: #f1f5f9; }
 .content p { color: #1e293b; }
 .content ul li, .content ol li { color: #1e293b; }
 .content code { background: #f1f5f9; color: #4f46e5; border: 1px solid #e2e8f0; }
-.content pre { background: #0f172a; border: 1px solid #1e293b; border-radius: 10px; }
-.content pre code { background: none; color: #e2e8f0; }
+.content pre:not(.syntax-highlighting) { background: #0f172a; border: 1px solid #1e293b; border-radius: 10px; }
+.content .syntax-highlighting { border: 1px solid #1e293b; border-radius: 10px; }
+.content pre:not(.syntax-highlighting) code { background: none; color: #e2e8f0; }
 .content blockquote { border-color: #818cf8; background: #f5f3ff; color: #4338ca; }
 .content table { color: #374151; }
 .content table th { border-bottom-color: #4f46e5; color: #334155; }

src-tauri/src/commands/render.rs

@@ -1,22 +1,25 @@
 use crate::application::{file_service, render_service};
-use crate::infrastructure::comrak_renderer::{ComrakPreviewRenderer, ComrakRenderer};
+use crate::infrastructure::comrak_renderer::{
+    syntax_css_for_theme, ComrakPreviewRenderer, ComrakRenderer,
+};
 
 #[tauri::command]
 pub fn render_markdown(content: String) -> String {
-    let renderer = ComrakPreviewRenderer {
-        theme: "base16-ocean.dark".to_string(),
-    };
+    let renderer = ComrakPreviewRenderer;
     render_service::render_string(&renderer, &content)
 }
 
 #[tauri::command]
 pub fn convert_file(path: String) -> Result<String, String> {
-    let renderer = ComrakRenderer {
-        theme: "InspiredGitHub".to_string(),
-    };
+    let renderer = ComrakRenderer;
     render_service::render_file(&renderer, &path)
 }
 
+#[tauri::command]
+pub fn get_syntax_highlight_css() -> String {
+    syntax_css_for_theme("base16-ocean.dark")
+}
+
 #[tauri::command]
 pub fn list_md_files(dir: String) -> Result<Vec<String>, String> {
     file_service::list_markdown_files(&dir)
@@ -41,7 +44,7 @@ mod tests {
     #[test]
     fn render_markdown_code_block() {
         let html = render_markdown("```rust\nfn main() {}\n```\n".to_string());
-        assert!(html.contains("<code") || html.contains("<pre>"));
+        assert!(html.contains("syntax-highlighting"));
     }
 
     #[test]
@@ -80,6 +83,18 @@ mod tests {
         assert!(result.is_err());
     }
 
+    #[test]
+    fn get_syntax_highlight_css_returns_non_empty() {
+        let css = get_syntax_highlight_css();
+        assert!(!css.is_empty());
+    }
+
+    #[test]
+    fn get_syntax_highlight_css_contains_wrapper_class() {
+        let css = get_syntax_highlight_css();
+        assert!(css.contains(".syntax-highlighting {"));
+    }
+
     #[test]
     fn list_md_files_sorted() {
         let dir = tmpdir("pena_list_sorted");

src-tauri/src/infrastructure/comrak_renderer.rs

@@ -1,19 +1,16 @@
 use comrak::plugins::syntect::SyntectAdapterBuilder;
 use comrak::{markdown_to_html_with_plugins, Options, Plugins};
+use syntect::highlighting::ThemeSet;
+use syntect::html::{css_for_theme_with_class_style, ClassStyle};
 
 use crate::domain::MarkdownRenderer;
 
-pub struct ComrakRenderer {
-    pub theme: String,
-}
-
-pub struct ComrakPreviewRenderer {
-    pub theme: String,
-}
+pub struct ComrakRenderer;
+pub struct ComrakPreviewRenderer;
 
 impl MarkdownRenderer for ComrakRenderer {
     fn render(&self, content: &str) -> String {
-        let adapter = SyntectAdapterBuilder::new().theme(&self.theme).build();
+        let adapter = SyntectAdapterBuilder::new().css().build();
         let mut options = Options::default();
         options.extension.table = true;
         options.extension.strikethrough = true;
@@ -27,10 +24,60 @@ impl MarkdownRenderer for ComrakRenderer {
 
 impl MarkdownRenderer for ComrakPreviewRenderer {
     fn render(&self, content: &str) -> String {
-        let adapter = SyntectAdapterBuilder::new().theme(&self.theme).build();
+        let adapter = SyntectAdapterBuilder::new().css().build();
         let options = Options::default();
         let mut plugins = Plugins::default();
         plugins.render.codefence_syntax_highlighter = Some(&adapter);
         markdown_to_html_with_plugins(content, &options, &plugins)
     }
 }
+
+pub fn syntax_css_for_theme(syntect_theme_name: &str) -> String {
+    let ts = ThemeSet::load_defaults();
+    let theme = match ts.themes.get(syntect_theme_name) {
+        Some(t) => t,
+        None => return String::new(),
+    };
+    match css_for_theme_with_class_style(theme, ClassStyle::Spaced) {
+        Ok(css) => css.replace(".code {", ".syntax-highlighting {"),
+        Err(_) => String::new(),
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn render_outputs_syntax_highlighting_class() {
+        let r = ComrakRenderer;
+        let html = r.render("```rust\nfn main() {}\n```\n");
+        assert!(html.contains("syntax-highlighting"));
+    }
+
+    #[test]
+    fn render_outputs_classed_spans() {
+        let r = ComrakRenderer;
+        let html = r.render("```rust\nfn main() {}\n```\n");
+        assert!(html.contains("<span class="));
+    }
+
+    #[test]
+    fn syntax_css_known_theme_contains_wrapper() {
+        let css = syntax_css_for_theme("base16-ocean.dark");
+        assert!(!css.is_empty());
+        assert!(css.contains(".syntax-highlighting {"));
+    }
+
+    #[test]
+    fn syntax_css_known_theme_contains_token_rules() {
+        let css = syntax_css_for_theme("base16-ocean.dark");
+        assert!(css.contains("color:") || css.contains("color :"));
+    }
+
+    #[test]
+    fn syntax_css_unknown_theme_returns_empty() {
+        let css = syntax_css_for_theme("nonexistent-theme-xyz");
+        assert!(css.is_empty());
+    }
+}

src-tauri/src/lib.rs

@@ -15,6 +15,7 @@ pub fn run() {
             commands::render::render_markdown,
             commands::render::convert_file,
             commands::render::list_md_files,
+            commands::render::get_syntax_highlight_css,
             commands::watch::start_watch,
             commands::watch::stop_watch,
             commands::theme::list_themes,

src/index.html

@@ -6,7 +6,6 @@
   <title>Pena — Markdown Viewer</title>
   <link rel="preconnect" href="https://fonts.googleapis.com">
   <link rel="stylesheet" href="https://fonts.googleapis.com/css2?family=Poppins:wght@400;500;600;700&family=Roboto+Mono&display=swap">
-  <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/highlight.js/11.9.0/styles/github.min.css">
 <link rel="stylesheet" href="style.css" />
 </head>
 <body>

src/main.js

@@ -1,8 +1,18 @@
 import { showHome, openPath } from './router.js';
 import { initCssModal } from './ui/css-modal.js';
 
+const { invoke } = window.__TAURI__.core;
 const win = window.__TAURI__.window.getCurrentWindow();
 
+async function injectSyntaxCss() {
+  const css = await invoke('get_syntax_highlight_css');
+  if (!css) return;
+  const style = document.createElement('style');
+  style.id = 'pena-syntax-style';
+  style.textContent = css;
+  document.head.appendChild(style);
+}
+
 document.getElementById('titlebar').addEventListener('mousedown', (e) => {
   if (e.target.closest('.titlebar-controls')) return;
   if (e.buttons === 1) win.startDragging();
@@ -32,5 +42,6 @@ document.getElementById('btn-open-dir').addEventListener('click', async () => {
 
 document.getElementById('btn-back').addEventListener('click', showHome);
 
+await injectSyntaxCss();
 await initCssModal();
 showHome();

src/style.css

@@ -451,7 +451,8 @@ body {
   border-radius: 4px;
   line-height: 1.4;
 }
-.content pre { background: #f4f4f7; padding: 20px 24px; border-radius: 6px; overflow-x: auto; margin: 16px 0; }
+.content pre { padding: 20px 24px; border-radius: 6px; overflow-x: auto; margin: 16px 0; }
+.content pre:not(.syntax-highlighting) { background: #f4f4f7; }
 .content pre code { background: none; padding: 0; font-weight: 400; font-size: 13px; }
 
 .content blockquote {