diff --git a/TODO.md b/TODO.md
index 97b907a..0102870 100644
--- a/TODO.md
+++ b/TODO.md
@@ -104,6 +104,7 @@
 
 # Current tasks
 
+- [x] Sticky thead: fix with border-collapse:separate, CSS class, --sticky-top var, +min-height:50vh on wrappers, +bulk delete for mots-clés
 - [x] Edit submit redirects to recapitulatif instead of staying on edit.php
 - [x] Mandatory auto-generated passwords on share links (no custom passwords, regenerate-only in edit, rate limit on password gate)
 - [x] .gitignore / .ignore: exclude *.db-wal and *.db-shm
diff --git a/app/public/admin/actions/language.php b/app/public/admin/actions/language.php
index 0f4126d..0989d9c 100644
--- a/app/public/admin/actions/language.php
+++ b/app/public/admin/actions/language.php
@@ -54,6 +54,16 @@ try {
             $db->deleteLanguage($id);
             break;
 
+        case 'delete_bulk':
+            $sourceIds = isset($_POST['selected_langs']) && is_array($_POST['selected_langs'])
+                ? array_map('intval', $_POST['selected_langs'])
+                : [];
+            if (empty($sourceIds)) throw new Exception("Aucune langue sélectionnée.");
+            foreach ($sourceIds as $sid) {
+                $db->deleteLanguage($sid);
+            }
+            break;
+
         default:
             throw new Exception("Action inconnue.");
     }
diff --git a/app/public/admin/actions/tag.php b/app/public/admin/actions/tag.php
index bb091e6..efe3a7d 100644
--- a/app/public/admin/actions/tag.php
+++ b/app/public/admin/actions/tag.php
@@ -58,6 +58,17 @@ try {
             $logger->logTagAction('delete', ['tag_id' => $id]);
             break;
 
+        case 'delete_bulk':
+            $sourceIds = isset($_POST['selected_tags']) && is_array($_POST['selected_tags'])
+                ? array_map('intval', $_POST['selected_tags'])
+                : [];
+            if (empty($sourceIds)) throw new Exception("Aucun mot-clé sélectionné.");
+            foreach ($sourceIds as $sid) {
+                $db->deleteTag($sid);
+                $logger->logTagAction('delete', ['tag_id' => $sid]);
+            }
+            break;
+
         default:
             throw new Exception("Action inconnue.");
     }
diff --git a/app/public/admin/contenus-langues-fragment.php b/app/public/admin/contenus-langues-fragment.php
index becad46..bc3706c 100644
--- a/app/public/admin/contenus-langues-fragment.php
+++ b/app/public/admin/contenus-langues-fragment.php
@@ -24,13 +24,19 @@ try {
     die('<div class="flash-error">Erreur : ' . htmlspecialchars($e->getMessage()) . '</div>');
 }
 ?>
-<div id="langues-bulk-actions" class="admin-bulk-actions" style="display:none">
+<div id="langues-bulk-actions" class="admin-bulk-actions" style="display:none;position:sticky;top:0;z-index:10">
     <strong><span id="langues-selected-count">0</span> langue(s) sélectionnée(s)</strong>
     <div class="admin-bulk-btns">
         <button type="button" class="btn btn--sm btn--secondary" onclick="languesCancelSelection()" title="Annuler la sélection">
             <svg xmlns="http://www.w3.org/2000/svg" width="32" height="32" fill="currentColor" viewBox="0 0 256 256"><path d="M208.49,191.51a12,12,0,0,1-17,17L128,145,64.49,208.49a12,12,0,0,1-17-17L111,128,47.51,64.49a12,12,0,0,1,17-17L128,111l63.51-63.52a12,12,0,0,1,17,17L145,128Z"/></svg>
             Annuler
         </button>
+        <button type="button" class="btn btn--sm btn--red admin-btn-delete"
+                onclick="languesConfirmBulkDelete()"
+                title="Supprimer les langues sélectionnées">
+            <svg xmlns="http://www.w3.org/2000/svg" width="32" height="32" fill="currentColor" viewBox="0 0 256 256"><path d="M216,48H176V40a24,24,0,0,0-24-24H104A24,24,0,0,0,80,40v8H40a8,8,0,0,0,0,16h8V208a16,16,0,0,0,16,16H192a16,16,0,0,0,16-16V64h8a8,8,0,0,0,0-16ZM96,40a8,8,0,0,1,8-8h48a8,8,0,0,1,8,8v8H96Zm96,168H64V64H192ZM112,104v64a8,8,0,0,1-16,0V104a8,8,0,0,1,16,0Zm48,0v64a8,8,0,0,1-16,0V104a8,8,0,0,1,16,0Z"/></svg>
+            Supprimer
+        </button>
         <button type="button" class="btn btn--sm btn--warning admin-btn-merge"
                 onclick="languesConfirmBulkMerge()"
                 title="Fusionner les langues sélectionnées">
@@ -48,7 +54,7 @@ try {
     <div id="langues-bulk-checkboxes"></div>
 </form>
 
-<table>
+<table class="admin-table--sticky">
     <thead>
         <tr>
             <th scope="col" style="width:1%"><input type="checkbox" onchange="languesToggleAll(this)"></th>
diff --git a/app/public/admin/contenus-motscles-fragment.php b/app/public/admin/contenus-motscles-fragment.php
index d807032..1370790 100644
--- a/app/public/admin/contenus-motscles-fragment.php
+++ b/app/public/admin/contenus-motscles-fragment.php
@@ -24,17 +24,23 @@ try {
     die('<div class="flash-error">Erreur : ' . htmlspecialchars($e->getMessage()) . '</div>');
 }
 ?>
-<div id="motscles-bulk-actions" class="admin-bulk-actions" style="display:none">
+<div id="motscles-bulk-actions" class="admin-bulk-actions" style="display:none;position:sticky;top:0;z-index:10">
     <strong><span id="motscles-selected-count">0</span> mot(s)-clé(s) sélectionné(s)</strong>
     <div class="admin-bulk-btns">
         <button type="button" class="btn btn--sm btn--secondary" onclick="motsclesCancelSelection()" title="Annuler la sélection">
             <svg xmlns="http://www.w3.org/2000/svg" width="32" height="32" fill="currentColor" viewBox="0 0 256 256"><path d="M208.49,191.51a12,12,0,0,1-17,17L128,145,64.49,208.49a12,12,0,0,1-17-17L111,128,47.51,64.49a12,12,0,0,1,17-17L128,111l63.51-63.52a12,12,0,0,1,17,17L145,128Z"/></svg>
             Annuler
         </button>
+        <button type="button" class="btn btn--sm btn--red admin-btn-delete"
+                onclick="motsclesConfirmBulkDelete()"
+                title="Supprimer les mots-clés sélectionnés">
+            <svg xmlns="http://www.w3.org/2000/svg" width="32" height="32" fill="currentColor" viewBox="0 0 256 256"><path d="M216,48H176V40a24,24,0,0,0-24-24H104A24,24,0,0,0,80,40v8H40a8,8,0,0,0,0,16h8V208a16,16,0,0,0,16,16H192a16,16,0,0,0,16-16V64h8a8,8,0,0,0,0-16ZM96,40a8,8,0,0,1,8-8h48a8,8,0,0,1,8,8v8H96Zm96,168H64V64H192ZM112,104v64a8,8,0,0,1-16,0V104a8,8,0,0,1,16,0Zm48,0v64a8,8,0,0,1-16,0V104a8,8,0,0,1,16,0Z"/></svg>
+            Supprimer
+        </button>
         <button type="button" class="btn btn--sm btn--warning admin-btn-merge"
                 onclick="motsclesConfirmBulkMerge()"
                 title="Fusionner les mots-clés sélectionnés">
-            <svg xmlns="http://www.w3.org/2000/svg" width="32" height="32" fill="currentColor" viewBox="0 0 256 256"><path d="M224,152V96a8,8,0,0,0-8-8H168V40a8,8,0,0,0-8-8H40a8,8,0,0,0-8,8v64h0v56a8,8,0,0,0,8,8H88v48a8,8,0,0,0,8,8H216a8,8,0,0,0,8-8V152Zm-68.69,56L48,100.69V59.31L196.69,208Zm-96-160h41.38L208,155.31v41.38ZM208,132.69,179.31,104H208Zm-56-56L123.31,48H152ZM48,123.31,76.69,152H48Zm56,56L132.69,208H104Z"></path></svg>
+            <svg xmlns="http://www.w3.org/2000/svg" width="32" height="32" fill="currentColor" viewBox="0 0 256 256"><path d="M224,152V96a8,8,0,0,0-8-8H168V40a8,8,0,0,0-8-8H40a8,8,0,0,0-8,8v64h0v56a8,8,0,0,0,8,8H88v48a8,8,0,0,0,8,8H216a8,8,0,0,0,8-8V152Zm-68.69,56L48,100.69V59.31L196.69,208Zm-96-160h41.38L208,155.31v41.38ZM208,132.69,179.31,104H208Zm-56-56L123.31,48H152ZM48,123.31,76.69,152H48Zm56,56L132.69,208H104Z"/></svg>
             Fusionner
         </button>
     </div>
@@ -48,7 +54,7 @@ try {
     <div id="motscles-bulk-checkboxes"></div>
 </form>
 
-<table>
+<table class="admin-table--sticky">
     <thead>
         <tr>
             <th scope="col" style="width:1%"><input type="checkbox" onchange="motsclesToggleAll(this)"></th>
diff --git a/app/public/assets/css/admin.css b/app/public/assets/css/admin.css
index 4e2d4b0..721bafe 100644
--- a/app/public/assets/css/admin.css
+++ b/app/public/assets/css/admin.css
@@ -74,16 +74,6 @@
     padding: 0 0 var(--space-2xl);
 }
 
-#admin-table-wrap table thead {
-    position: sticky;
-    top: 0;
-    z-index: 5;
-}
-
-#admin-table-wrap table thead th {
-    background: var(--bg-primary);
-}
-
 .admin-body main > table tbody tr:nth-child(even) {
     background: var(--bg-secondary);
 }
diff --git a/app/public/assets/css/components/tables.css b/app/public/assets/css/components/tables.css
index a093bb9..2767526 100644
--- a/app/public/assets/css/components/tables.css
+++ b/app/public/assets/css/components/tables.css
@@ -26,3 +26,17 @@ td {
   border-bottom: 1px solid var(--border-primary);
   vertical-align: top;
 }
+
+/* Sticky header — border-collapse:collapse blocks position:sticky in Chrome.
+   --sticky-top is set by JS when a bulk actions bar appears above the table. */
+.admin-table--sticky {
+  border-collapse: separate;
+  border-spacing: 0;
+}
+
+.admin-table--sticky thead th {
+  position: sticky;
+  top: var(--sticky-top, 0px);
+  z-index: 5;
+  background: var(--bg-primary);
+}
diff --git a/app/templates/admin/contenus.php b/app/templates/admin/contenus.php
index d814704..ed2c364 100644
--- a/app/templates/admin/contenus.php
+++ b/app/templates/admin/contenus.php
@@ -70,7 +70,7 @@
                      hx-get="/admin/contenus-langues-fragment.php"
                      hx-trigger="load"
                      hx-swap="innerHTML"
-                     style="max-height:50vh;overflow-y:auto">
+                     style="min-height:50vh;max-height:50vh;overflow-y:auto">
                     <div style="padding:var(--space-m); text-align:center; color:var(--text-tertiary)">
                         <img alt="Chargement…" class="htmx-indicator" width="24" src="/assets/img/bars.svg" style="opacity:0.5">
                     </div>
@@ -96,7 +96,7 @@
                      hx-get="/admin/contenus-motscles-fragment.php"
                      hx-trigger="load"
                      hx-swap="innerHTML"
-                     style="max-height:50vh;overflow-y:auto">
+                     style="min-height:50vh;max-height:50vh;overflow-y:auto">
                     <div style="padding:var(--space-m); text-align:center; color:var(--text-tertiary)">
                         <img alt="Chargement…" class="htmx-indicator" width="24" src="/assets/img/bars.svg" style="opacity:0.5">
                     </div>
@@ -323,6 +323,21 @@
     </div>
 </dialog>
 
+<dialog id="langues-bulk-delete-dialog" class="admin-dialog admin-dialog--sm" aria-labelledby="langues-bulk-delete-title">
+    <div class="admin-dialog__header">
+        <h2 id="langues-bulk-delete-title">Supprimer des langues</h2>
+        <button type="button" class="admin-dialog__close" aria-label="Fermer"
+                onclick="this.closest('dialog').close()">&#x2715;</button>
+    </div>
+    <div class="admin-dialog__alert">
+        <p>Supprimer définitivement <strong><span id="langues-bulk-delete-count"></span> langue(s)</strong>&nbsp;? Cette action est irréversible.</p>
+    </div>
+    <div class="admin-dialog__footer">
+        <button type="button" class="btn btn--danger" onclick="languesExecBulkDelete()">Supprimer</button>
+        <button type="button" class="btn btn--secondary" onclick="this.closest('dialog').close()">Annuler</button>
+    </div>
+</dialog>
+
 <script>
 let _languesPendingForm = null;
 
@@ -371,7 +386,18 @@ function languesToggleAll(src) {
 function languesUpdateBulk() {
     const n = document.querySelectorAll('input[name="selected_langs[]"]:checked').length;
     document.getElementById('langues-selected-count').textContent = n;
-    document.getElementById('langues-bulk-actions').style.display = n > 1 ? 'flex' : 'none';
+    const bar = document.getElementById('langues-bulk-actions');
+    const wrap = document.getElementById('langues-table-wrap');
+    const visible = n > 1;
+    bar.style.display = visible ? 'flex' : 'none';
+    // Force reflow then read bar height for sticky th offset
+    if (visible) {
+        requestAnimationFrame(() => {
+            wrap.style.setProperty('--sticky-top', bar.offsetHeight + 'px');
+        });
+    } else {
+        wrap.style.setProperty('--sticky-top', '0px');
+    }
 }
 
 function languesCancelSelection() {
@@ -379,6 +405,28 @@ function languesCancelSelection() {
     languesUpdateBulk();
 }
 
+function languesConfirmBulkDelete() {
+    const checked = document.querySelectorAll('input[name="selected_langs[]"]:checked');
+    if (checked.length < 1) return;
+    document.getElementById('langues-bulk-delete-count').textContent = checked.length;
+    document.getElementById('langues-bulk-delete-dialog').showModal();
+}
+
+function languesExecBulkDelete() {
+    const container = document.getElementById('langues-bulk-checkboxes');
+    container.innerHTML = '';
+    document.querySelectorAll('input[name="selected_langs[]"]:checked').forEach(cb => {
+        const inp = document.createElement('input');
+        inp.type = 'hidden';
+        inp.name = 'selected_langs[]';
+        inp.value = cb.value;
+        container.appendChild(inp);
+    });
+    document.getElementById('langues-bulk-form').querySelector('input[name="action"]').value = 'delete_bulk';
+    document.getElementById('langues-bulk-delete-dialog').close();
+    document.getElementById('langues-bulk-form').submit();
+}
+
 function languesConfirmBulkMerge() {
     const checked = document.querySelectorAll('input[name="selected_langs[]"]:checked');
     if (checked.length < 2) return;
@@ -454,6 +502,21 @@ document.addEventListener('htmx:afterSwap', function(evt) {
     </div>
 </dialog>
 
+<dialog id="motscles-bulk-delete-dialog" class="admin-dialog admin-dialog--sm" aria-labelledby="motscles-bulk-delete-title">
+    <div class="admin-dialog__header">
+        <h2 id="motscles-bulk-delete-title">Supprimer des mots-clés</h2>
+        <button type="button" class="admin-dialog__close" aria-label="Fermer"
+                onclick="this.closest('dialog').close()">&#x2715;</button>
+    </div>
+    <div class="admin-dialog__alert">
+        <p>Supprimer définitivement <strong><span id="motscles-bulk-delete-count"></span> mot(s)-clé(s)</strong>&nbsp;? Cette action est irréversible.</p>
+    </div>
+    <div class="admin-dialog__footer">
+        <button type="button" class="btn btn--danger" onclick="motsclesExecBulkDelete()">Supprimer</button>
+        <button type="button" class="btn btn--secondary" onclick="this.closest('dialog').close()">Annuler</button>
+    </div>
+</dialog>
+
 <script>
 let _motsclesPendingForm = null;
 
@@ -502,7 +565,18 @@ function motsclesToggleAll(src) {
 function motsclesUpdateBulk() {
     const n = document.querySelectorAll('input[name="selected_tags[]"]:checked').length;
     document.getElementById('motscles-selected-count').textContent = n;
-    document.getElementById('motscles-bulk-actions').style.display = n > 1 ? 'flex' : 'none';
+    const bar = document.getElementById('motscles-bulk-actions');
+    const wrap = document.getElementById('motscles-table-wrap');
+    const visible = n > 1;
+    bar.style.display = visible ? 'flex' : 'none';
+    // Force reflow then read bar height for sticky th offset
+    if (visible) {
+        requestAnimationFrame(() => {
+            wrap.style.setProperty('--sticky-top', bar.offsetHeight + 'px');
+        });
+    } else {
+        wrap.style.setProperty('--sticky-top', '0px');
+    }
 }
 
 function motsclesConfirmBulkMerge() {
@@ -540,6 +614,28 @@ function motsclesCancelSelection() {
     motsclesUpdateBulk();
 }
 
+function motsclesConfirmBulkDelete() {
+    const checked = document.querySelectorAll('input[name="selected_tags[]"]:checked');
+    if (checked.length < 1) return;
+    document.getElementById('motscles-bulk-delete-count').textContent = checked.length;
+    document.getElementById('motscles-bulk-delete-dialog').showModal();
+}
+
+function motsclesExecBulkDelete() {
+    const container = document.getElementById('motscles-bulk-checkboxes');
+    container.innerHTML = '';
+    document.querySelectorAll('input[name="selected_tags[]"]:checked').forEach(cb => {
+        const inp = document.createElement('input');
+        inp.type = 'hidden';
+        inp.name = 'selected_tags[]';
+        inp.value = cb.value;
+        container.appendChild(inp);
+    });
+    document.getElementById('motscles-bulk-form').querySelector('input[name="action"]').value = 'delete_bulk';
+    document.getElementById('motscles-bulk-delete-dialog').close();
+    document.getElementById('motscles-bulk-form').submit();
+}
+
 document.addEventListener('htmx:afterSwap', function(evt) {
     if (evt.target.id === 'motscles-table-wrap') {
         document.querySelectorAll('input[name="selected_tags[]"]').forEach(cb => cb.addEventListener('change', motsclesUpdateBulk));
diff --git a/app/templates/admin/index-table.php b/app/templates/admin/index-table.php
index 838199e..3464ff1 100644
--- a/app/templates/admin/index-table.php
+++ b/app/templates/admin/index-table.php
@@ -44,7 +44,7 @@ $sortArrow = function(string $col) use ($sortCol, $sortDir): string {
 <div id="bulk-checkboxes"></div>
 </form>
 
-<table>
+<table class="admin-table--sticky">
     <thead>
         <tr>
             <th scope="col"><input type="checkbox" onchange="toggleAll(this)"></th>
diff --git a/app/templates/admin/index.php b/app/templates/admin/index.php
index a234945..da88ada 100644
--- a/app/templates/admin/index.php
+++ b/app/templates/admin/index.php
@@ -1,6 +1,6 @@
 <script>
 function toggleAll(src){document.querySelectorAll('input[name="selected_theses[]"]').forEach(cb=>cb.checked=src.checked);updateBulk();}
-function updateBulk(){const n=document.querySelectorAll('input[name="selected_theses[]"]:checked').length;const b=document.getElementById('bulk-actions');document.getElementById('selected-count').textContent=n;b.style.display=n>0?'flex':'none';}
+function updateBulk(){const n=document.querySelectorAll('input[name="selected_theses[]"]:checked').length;const b=document.getElementById('bulk-actions');document.getElementById('selected-count').textContent=n;b.style.display=n>0?'flex':'none';document.getElementById('admin-table-wrap').style.setProperty('--sticky-top',n>0?b.offsetHeight+'px':'0px');}
 function getSelectedIds(){return Array.from(document.querySelectorAll('input[name="selected_theses[]"]:checked')).map(cb=>cb.value);}
 function confirmBulk(act){const ids=getSelectedIds();if(!ids.length){document.getElementById('no-selection-dialog').showModal();return;}const n=ids.length;document.getElementById('bulk-action-input').value=act;if(act==='delete'){document.getElementById('bulk-delete-count').textContent=n;document.getElementById('bulk-delete-dialog').showModal();}else{document.getElementById('bulk-confirm-word').textContent=act=='publish'?'Publier':'Dépublier';document.getElementById('bulk-confirm-count').textContent=n;document.getElementById('bulk-confirm-dialog').showModal();}}
 function execBulk(){const a=document.getElementById('bulk-action-input').value;const f=document.getElementById('bulk-form');f.action = a=='delete' ? 'actions/delete.php' : 'actions/publish.php';const c=document.getElementById('bulk-checkboxes');c.innerHTML='';getSelectedIds().forEach(id=>{const inp=document.createElement('input');inp.type='hidden';inp.name='selected_theses[]';inp.value=id;c.appendChild(inp);});f.submit();}