diff --git a/archive/css/components.css b/archive/css/components.css
index 8a5f08d..e2f38a0 100644
--- a/archive/css/components.css
+++ b/archive/css/components.css
@@ -643,12 +643,7 @@ input[type="checkbox"] {
     color: var(--text-muted);
 }
 
-/* ── Welcome screen list ─────────────────────────────────────────────────── */
-.welcome-list {
-    text-align: left;
-    margin: 0.5rem auto;
-    max-width: 400px;
-}
+/* .welcome-list lives in shared/base.css. */
 
 /* ── Windows path tip (inside welcome screen) ────────────────────────────── */
 .windows-tip {
diff --git a/archive/css/layout.css b/archive/css/layout.css
index bc9ee69..a5c1e53 100644
--- a/archive/css/layout.css
+++ b/archive/css/layout.css
@@ -191,24 +191,7 @@
 }
 
 /* Empty State — positioned below the app header */
-.empty-state {
-    position: absolute;
-    top: 50px; /* clear the header */
-    left: 0;
-    right: 0;
-    bottom: 0;
-    display: flex;
-    align-items: center;
-    justify-content: center;
-    background: var(--bg);
-    z-index: 10;
-}
-
-.empty-state-content {
-    text-align: center;
-    max-width: 500px;
-    padding: 2rem;
-}
+/* .empty-state / .empty-state__inner / .welcome-list live in shared/base.css. */
 
 /* Project warning banner */
 .project-warning-banner {
@@ -233,16 +216,6 @@
     flex-shrink: 0;
 }
 
-.empty-state-content h2 {
-    color: var(--text);
-    margin-bottom: 1rem;
-}
-
-.empty-state-content p {
-    margin-bottom: 1rem;
-    color: var(--text-muted);
-}
-
 /* Project access warning banner */
 .project-warning-banner {
     display: flex;
diff --git a/archive/js/app.js b/archive/js/app.js
index 3537e32..e7500de 100644
--- a/archive/js/app.js
+++ b/archive/js/app.js
@@ -272,7 +272,7 @@
     function showHttpErrorState(message) {
         var el = document.getElementById('noDirectoryMessage');
         if (!el) return;
-        var content = el.querySelector('.empty-state-content');
+        var content = el.querySelector('.empty-state__inner');
         if (content) {
             content.innerHTML =
                 '<h2>Could not connect to server</h2>' +
@@ -302,8 +302,8 @@
     function showUnsupportedBrowserMessage() {
         const app = document.getElementById('appContainer');
         app.innerHTML = `
-            <div class="empty-state">
-                <div class="empty-state-content">
+            <div class="empty-state empty-state--overlay">
+                <div class="empty-state__inner empty-state__inner--centered">
                     <h2>Browser Not Supported</h2>
                     <p>This application requires a Chromium-based browser (Chrome, Edge, Brave) with File System Access API support.</p>
                     <p>Please use one of these browsers to access the Archive Browser.</p>
diff --git a/archive/template.html b/archive/template.html
index 7f1fdff..d8e36ba 100644
--- a/archive/template.html
+++ b/archive/template.html
@@ -237,8 +237,8 @@
         </div>
 
         <!-- No Directory Selected Message -->
-        <div id="noDirectoryMessage" class="empty-state">
-            <div class="empty-state-content">
+        <div id="noDirectoryMessage" class="empty-state empty-state--overlay">
+            <div class="empty-state__inner empty-state__inner--centered">
                 <h2>Welcome to ZDDC Archive</h2>
                 <p>Click <strong>Add Local Directory</strong> to select an archive folder to browse.</p>
                 <p>This browser provides a convenient interface for searching and retrieving files from ZDDC-compliant archives.</p>
diff --git a/browse/css/base.css b/browse/css/base.css
index 65ec2b4..1d2b5ff 100644
--- a/browse/css/base.css
+++ b/browse/css/base.css
@@ -22,35 +22,7 @@ body {
     min-height: 0;
 }
 
-/* Empty / first-paint state */
-.empty-state {
-    flex: 1;
-    display: flex;
-    align-items: center;
-    justify-content: center;
-    padding: 2rem;
-}
-
-.empty-state__inner {
-    max-width: 640px;
-    color: var(--text-muted);
-    line-height: 1.5;
-}
-
-.empty-state__inner h2 {
-    color: var(--text);
-    margin: 0 0 1rem 0;
-    font-size: 1.5rem;
-}
-
-.empty-state__inner ul {
-    margin: 1rem 0;
-    padding-left: 1.5rem;
-}
-
-.empty-state__inner li {
-    margin: 0.4rem 0;
-}
+/* .empty-state / .empty-state__inner live in shared/base.css. */
 
 /* .hidden lives in shared/base.css; no per-tool override needed. */
 
diff --git a/classifier/css/layout.css b/classifier/css/layout.css
index 946ac78..4caac9a 100644
--- a/classifier/css/layout.css
+++ b/classifier/css/layout.css
@@ -1,46 +1,8 @@
 /* Classifier layout — tokens from shared/base.css */
 
-/* Empty State — positioned below the app header */
-.empty-state {
-    position: absolute;
-    top: 50px; /* clear the header */
-    left: 0;
-    right: 0;
-    bottom: 0;
-    display: flex;
-    align-items: center;
-    justify-content: center;
-    background: var(--bg);
-    z-index: 10;
-}
-
-.empty-state-content {
-    text-align: center;
-    max-width: 500px;
-    padding: 2rem;
-}
-
-.empty-state-content h2 {
-    color: var(--text);
-    margin-bottom: 1rem;
-}
-
-.empty-state-content p {
-    margin-bottom: 1rem;
-    color: var(--text-muted);
-}
-
-.empty-state-content .note {
-    font-size: 0.85rem;
-    font-style: italic;
-}
-
-.welcome-list {
-    text-align: left;
-    margin: 0.5rem auto;
-    max-width: 400px;
-}
-
+/* .empty-state / .empty-state__inner / .welcome-list live in
+   shared/base.css. Classifier keeps the .drag-over modifier locally
+   because it's the only tool whose empty state is a drop target. */
 .empty-state.drag-over {
     background: var(--primary-light);
     outline: 2px dashed var(--primary);
diff --git a/classifier/template.html b/classifier/template.html
index 05de22d..85c1c18 100644
--- a/classifier/template.html
+++ b/classifier/template.html
@@ -129,8 +129,8 @@
             </div>
 
             <!-- Empty State — shown until a directory is selected -->
-            <div id="welcomeScreen" class="empty-state">
-                <div class="empty-state-content">
+            <div id="welcomeScreen" class="empty-state empty-state--overlay">
+                <div class="empty-state__inner empty-state__inner--centered">
                     <h2>ZDDC Classifier</h2>
                     <p>Rename a folder of files to ZDDC format using a spreadsheet interface.</p>
                     <p>Open a directory, fill in tracking number, revision, status, and title for each file, then save — the files are renamed on disk.</p>
diff --git a/shared/base.css b/shared/base.css
index a09d7c8..65147d9 100644
--- a/shared/base.css
+++ b/shared/base.css
@@ -349,7 +349,83 @@ a:hover {
     font-size: 1.1rem;
 }
 
-/* Toast CSS lives in classifier/css/base.css — only that tool uses toasts. */
+/* Toast CSS lives in shared/toast.css; loaded by every tool's build. */
+
+/* ── Empty state ──────────────────────────────────────────────────────────── */
+/* The "nothing's loaded yet" screen. By default, centers its inner
+   content in whatever space the parent gives it (works inside a flex
+   column). Tools that need to overlay an existing layout (archive,
+   classifier) add .empty-state--overlay; the screen pins below the
+   app header and on top of whatever underlying layout already exists.
+   Inner content uses BEM-ish .empty-state__inner with two variants:
+   plain (left-aligned, doc-style) and --centered (centered card). */
+
+.empty-state {
+    flex: 1;
+    display: flex;
+    align-items: center;
+    justify-content: center;
+    padding: 2rem;
+    background: var(--bg);
+}
+
+.empty-state--overlay {
+    position: absolute;
+    top: 50px; /* clear the app-header */
+    left: 0;
+    right: 0;
+    bottom: 0;
+    z-index: 10;
+    flex: none;
+}
+
+.empty-state__inner {
+    max-width: 640px;
+    color: var(--text-muted);
+    line-height: 1.5;
+}
+
+.empty-state__inner h2 {
+    color: var(--text);
+    margin: 0 0 1rem;
+    font-size: 1.5rem;
+}
+
+.empty-state__inner p {
+    margin-bottom: 1rem;
+}
+
+.empty-state__inner ul,
+.empty-state__inner ol {
+    margin: 1rem 0;
+    padding-left: 1.5rem;
+}
+
+.empty-state__inner li {
+    margin: 0.4rem 0;
+}
+
+.empty-state__inner .note {
+    font-size: 0.85rem;
+    font-style: italic;
+}
+
+/* Centered variant: tighter max-width + centered text. Used by tools
+   whose empty-state reads as a "welcome card" (archive, classifier)
+   rather than a doc-style page (browse). */
+.empty-state__inner--centered {
+    max-width: 500px;
+    text-align: center;
+    padding: 2rem;
+}
+
+/* Bullet list inside an empty-state — keep the bullets left-aligned
+   even when the surrounding card is centered. */
+.welcome-list {
+    text-align: left;
+    margin: 0.5rem auto;
+    max-width: 400px;
+}
 
 /* ── Theme and help icon buttons ─────────────────────────────────────────── */
 #theme-btn,