diff --git a/frontend/app.js b/frontend/app.js
index 15504ab..6a51793 100644
--- a/frontend/app.js
+++ b/frontend/app.js
@@ -3308,7 +3308,8 @@
 
     const openNewWindowBtn = el("button", { class: "btn-action", title: "Ouvrir dans une nouvelle fenetre" }, [icon("external-link", 14), document.createTextNode("pop-out")]);
     openNewWindowBtn.addEventListener("click", () => {
-      const popoutUrl = `/popout/${encodeURIComponent(data.vault)}/${encodeURIComponent(data.path)}`;
+      const theme = document.documentElement.getAttribute('data-theme') || 'dark';
+      const popoutUrl = `/popout/${encodeURIComponent(data.vault)}/${encodeURIComponent(data.path)}?theme=${theme}`;
       window.open(popoutUrl, `popout_${data.vault}_${data.path.replace(/[^a-zA-Z0-9]/g, "_")}`, "width=1000,height=700,menubar=no,toolbar=no,location=no,status=no,resizable=yes,scrollbars=no");
     });
 
diff --git a/frontend/js/palette.js b/frontend/js/palette.js
index 963b920..177e3e3 100644
--- a/frontend/js/palette.js
+++ b/frontend/js/palette.js
@@ -40,7 +40,7 @@ function getCMDS() {
   _cmdsCache = [
   { id:'home',         label:t('palette.cmd_back_home'),      desc:t('palette.cmd_back_home_desc'),   cat:'Navigation',  act:()=>{close();triggerGoHome();} },
   { id:'edit-current', label:'✏️ '+t('editor.edit'),           desc:t('editor.edit_current_desc'),      cat:'Fichiers', act:()=>{close();const f=getCurrentFile();if(f)openEditor(f.vault,f.path);else showToast(t('toast.no_open_file'),'error');} },
-  { id:'popout',       label:'🪟 Pop-out',                    desc:t('palette.popout_desc'),            cat:'Fichiers',  act:()=>{close();const f=getCurrentFile();if(f)window.open(`/popout/${encodeURIComponent(f.vault)}/${encodeURIComponent(f.path)}`,'popout','width=1000,height=700');else showToast(t('toast.no_open_file'),'error');} },
+  { id:'popout',       label:'🪟 Pop-out',                    desc:t('palette.popout_desc'),            cat:'Fichiers',  act:()=>{close();const f=getCurrentFile();if(f)window.open(`/popout/${encodeURIComponent(f.vault)}/${encodeURIComponent(f.path)}?theme=${document.documentElement.getAttribute('data-theme')||'dark'}`,'popout','width=1000,height=700');else showToast(t('toast.no_open_file'),'error');} },
   { id:'create-file',  label:t('palette.cmd_create_file'),     desc:t('palette.cmd_create_file_desc'),   cat:'Fichiers', act:()=>startBrowse('create-file') },
   { id:'delete-file',  label:'🗑️ '+t('file.delete'),            desc:t('palette.delete_file_desc'),    cat:'Fichiers', act:()=>startBrowse('delete-file') },
   { id:'delete-cur',   label:'🗑️ '+t('palette.delete_current'), desc:t('palette.delete_current_desc'), cat:'Fichiers', act:async()=>{close();await delCurFile();} },
diff --git a/frontend/js/viewer.js b/frontend/js/viewer.js
index a6ee8ed..5469344 100644
--- a/frontend/js/viewer.js
+++ b/frontend/js/viewer.js
@@ -571,7 +571,8 @@ export function renderFile(data) {
 
   const openNewWindowBtn = el("button", { class: "btn-action", title: t("forge.popout") }, [icon("external-link", 14), document.createTextNode(t("forge.popout_label"))]);
   openNewWindowBtn.addEventListener("click", () => {
-    const popoutUrl = `/popout/${encodeURIComponent(data.vault)}/${encodeURIComponent(data.path)}`;
+    const theme = document.documentElement.getAttribute('data-theme') || 'dark';
+    const popoutUrl = `/popout/${encodeURIComponent(data.vault)}/${encodeURIComponent(data.path)}?theme=${theme}`;
     window.open(popoutUrl, `popout_${data.vault}_${data.path.replace(/[^a-zA-Z0-9]/g, "_")}`, "width=1000,height=700,menubar=no,toolbar=no,location=no,status=no,resizable=yes,scrollbars=no");
   });
 
diff --git a/frontend/popout.html b/frontend/popout.html
index d67e33f..cc9b53b 100644
--- a/frontend/popout.html
+++ b/frontend/popout.html
@@ -5,7 +5,13 @@
   <meta name="viewport" content="width=device-width, initial-scale=1.0">
   <title>ObsiGate - Popout</title>
   <script>
-    document.documentElement.setAttribute('data-theme', localStorage.getItem('obsigate-theme') || 'dark');
+    // Inherit theme from opener or localStorage — query param has priority
+    (function() {
+      var m = location.search.match(/theme=([^&]+)/);
+      var theme = (m && m[1]) || localStorage.getItem('obsigate-theme') || 'dark';
+      document.documentElement.setAttribute('data-theme', theme);
+      if (m && m[1]) { localStorage.setItem('obsigate-theme', theme); }
+    })();
   </script>
   <link rel="stylesheet" href="/static/style.css">
   <script src="https://cdn.jsdelivr.net/npm/mermaid@11/dist/mermaid.min.js"></script>