internal/web/static/app.css

@@ -586,6 +586,20 @@ a.admin-link:hover { color: var(--fg); text-decoration: underline; }
   border-color: var(--ok);
 }
 
+/* #260: static-width success feedback. Label and checkmark stack in one
+   grid cell, so the button is always as wide as the wider of the two and
+   never shifts on click. Feedback is a pure .ok class toggle. */
+.swapbtn {
+  display: inline-grid;
+}
+.swapbtn > * {
+  grid-area: 1 / 1;
+  justify-self: center;
+}
+.swapbtn .swap-check { visibility: hidden; }
+.swapbtn.ok .swap-check { visibility: visible; }
+.swapbtn.ok .swap-label { visibility: hidden; }
+
 /* headings: unified treatment (mirrors .side-section h3) */
 .settings-head h1, .paste-title-bar h1, .head-row h1, .inner h1 {
   letter-spacing: -0.01em;

internal/web/static/new.js

@@ -192,18 +192,16 @@ async function create() {
 // button, password auto-unlock, then redirect to the paste.
 function finishCreate(data) {
   const url = location.origin + '/' + (data.custom_slug || data.id);
-  showResult('<a href="' + url + '">' + url + '</a> <button class="btn btn-icon" id="result-copy" title="Copy URL" type="button">⧉</button>', 'ok');
+  // #260 attempt 2: .swapbtn markup — label and checkmark share one grid
+  // cell, so the button width is static and feedback is a class toggle.
+  showResult('<a href="' + url + '">' + url + '</a> <button class="btn btn-icon swapbtn" id="result-copy" title="Copy URL" type="button"><span class="swap-label">Copy</span><span class="swap-check">✓</span></button>', 'ok');
   $('result').dataset.token = data.deletion_token || '';
   const copyBtn = document.getElementById('result-copy');
   copyBtn.addEventListener('click', () => {
     try {
       navigator.clipboard.writeText(url);
       copyBtn.classList.add('ok');               // in-place success feedback (#53)
-      // #260: pin the pre-swap width so the wider/narrower glyph never
-      // shifts neighbouring elements; release it when the label restores.
-      copyBtn.style.minWidth = Math.ceil(copyBtn.getBoundingClientRect().width) + 'px';
-      copyBtn.textContent = '✓';
-      setTimeout(() => { copyBtn.classList.remove('ok'); copyBtn.textContent = '⧉'; copyBtn.style.minWidth = ''; }, 2000);
+      setTimeout(() => copyBtn.classList.remove('ok'), 2000);
     } catch(e) { toast('Copy failed', 'error'); }
   });
   // token carried via sessionStorage, never in the URL (#143)

internal/web/static/paste.js

@@ -18,17 +18,12 @@ function toggleStats() {
 }
 function copyFeedback(btn) {
   if (!btn) return;
-  if (!btn.dataset.label) btn.dataset.label = btn.textContent; // remember the original label (Copy/Link)
-  // #260: keep the button width static during the feedback so surrounding
-  // elements never jump. Pin the pre-swap width, release it on restore.
-  if (!btn.dataset.pinned) {
-    btn.style.minWidth = Math.ceil(btn.getBoundingClientRect().width) + 'px';
-    btn.dataset.pinned = '1';
-  }
+  // #260 attempt 2: .swapbtn stacks the label and checkmark in the same grid
+  // cell, so the button width is always the wider of the two and never moves.
+  // Feedback is a pure class toggle; no width pinning, no textContent swap.
   btn.classList.add('ok');
-  btn.textContent = '✓';
   clearTimeout(btn._okh);
-  btn._okh = setTimeout(() => { btn.classList.remove('ok'); btn.textContent = btn.dataset.label; }, 2000);
+  btn._okh = setTimeout(() => btn.classList.remove('ok'), 2000);
 }
 function copyContent(btn) {
   navigator.clipboard.writeText(document.getElementById('raw-content').value)

internal/web/templates/paste.html

@@ -8,8 +8,8 @@
       <div class="spacer"></div>
       <button type="button" class="iconbtn wrap-toggle" title="Toggle line wrap" aria-pressed="false">Wrap</button>
       <a class="iconbtn" href="/raw/{{.ID}}">Raw</a>
-      <a class="iconbtn" href="#" id="copy-link-btn">Link</a>
-      <a class="iconbtn" href="#" id="copy-btn">Copy</a>
+      <a class="iconbtn swapbtn" href="#" id="copy-link-btn"><span class="swap-label">Link</span><span class="swap-check">✓</span></a>
+      <a class="iconbtn swapbtn" href="#" id="copy-btn"><span class="swap-label">Copy</span><span class="swap-check">✓</span></a>
       {{if .DeletionToken}}<a class="iconbtn danger" href="#" id="delete-btn">Delete</a>{{end}}
     </div>
   </div>