diff --git a/mkdocs.yml b/mkdocs.yml
index 7428fb1..802e8b5 100644
--- a/mkdocs.yml
+++ b/mkdocs.yml
@@ -19,6 +19,7 @@ theme:
     - navigation.expand
     - navigation.instant
     - navigation.sections
+    - announce.dismiss
   palette:
     # Palette toggle for light mode
     - scheme: default
diff --git a/site/20-slice/index.html b/site/20-slice/index.html
index 2a432aa..97ee4b4 100644
--- a/site/20-slice/index.html
+++ b/site/20-slice/index.html
@@ -120,11 +120,18 @@
         <aside class="md-banner">
           <div class="md-banner__inner md-grid md-typeset">
             
+              <button class="md-banner__button md-icon" aria-label="Don't show this again">
+                
+                <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M19 6.41 17.59 5 12 10.59 6.41 5 5 6.41 10.59 12 5 17.59 6.41 19 12 13.41 17.59 19 19 17.59 13.41 12 19 6.41Z"/></svg>
+              </button>
+            
             
 📢 Two new full sections are now available: <a href="https://100go.co/5-interface-pollution/">#5: Interface pollution</a> and <a href="https://100go.co/92-false-sharing/">#92: Writing concurrent code that leads to false sharing</a>.
 
           </div>
           
+            <script>var content,el=document.querySelector("[data-md-component=announce]");el&&(content=el.querySelector(".md-typeset"),__md_hash(content.innerHTML)===__md_get("__announce")&&(el.hidden=!0))</script>
+          
         </aside>
       
     </div>
@@ -1087,7 +1094,7 @@
     </div>
     
     
-    <script id="__config" type="application/json">{"base": "..", "features": ["navigation.tabs", "navigation.tabs.sticky", "search.highlight", "search.share", "search.suggest", "content.code.copy", "navigation.expand", "navigation.instant", "navigation.sections"], "search": "../assets/javascripts/workers/search.b8dbb3d2.min.js", "translations": {"clipboard.copied": "Copied to clipboard", "clipboard.copy": "Copy to clipboard", "search.result.more.one": "1 more on this page", "search.result.more.other": "# more on this page", "search.result.none": "No matching documents", "search.result.one": "1 matching document", "search.result.other": "# matching documents", "search.result.placeholder": "Type to start searching", "search.result.term.missing": "Missing", "select.version": "Select version"}}</script>
+    <script id="__config" type="application/json">{"base": "..", "features": ["navigation.tabs", "navigation.tabs.sticky", "search.highlight", "search.share", "search.suggest", "content.code.copy", "navigation.expand", "navigation.instant", "navigation.sections", "announce.dismiss"], "search": "../assets/javascripts/workers/search.b8dbb3d2.min.js", "translations": {"clipboard.copied": "Copied to clipboard", "clipboard.copy": "Copy to clipboard", "search.result.more.one": "1 more on this page", "search.result.more.other": "# more on this page", "search.result.none": "No matching documents", "search.result.one": "1 matching document", "search.result.other": "# matching documents", "search.result.placeholder": "Type to start searching", "search.result.term.missing": "Missing", "select.version": "Select version"}}</script>
     
     
       <script src="../assets/javascripts/bundle.8fd75fb4.min.js"></script>
diff --git a/site/28-maps-memory-leaks/index.html b/site/28-maps-memory-leaks/index.html
index 34c4760..4a6ac68 100644
--- a/site/28-maps-memory-leaks/index.html
+++ b/site/28-maps-memory-leaks/index.html
@@ -120,11 +120,18 @@
         <aside class="md-banner">
           <div class="md-banner__inner md-grid md-typeset">
             
+              <button class="md-banner__button md-icon" aria-label="Don't show this again">
+                
+                <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M19 6.41 17.59 5 12 10.59 6.41 5 5 6.41 10.59 12 5 17.59 6.41 19 12 13.41 17.59 19 19 17.59 13.41 12 19 6.41Z"/></svg>
+              </button>
+            
             
 📢 Two new full sections are now available: <a href="https://100go.co/5-interface-pollution/">#5: Interface pollution</a> and <a href="https://100go.co/92-false-sharing/">#92: Writing concurrent code that leads to false sharing</a>.
 
           </div>
           
+            <script>var content,el=document.querySelector("[data-md-component=announce]");el&&(content=el.querySelector(".md-typeset"),__md_hash(content.innerHTML)===__md_get("__announce")&&(el.hidden=!0))</script>
+          
         </aside>
       
     </div>
@@ -1098,7 +1105,7 @@
     </div>
     
     
-    <script id="__config" type="application/json">{"base": "..", "features": ["navigation.tabs", "navigation.tabs.sticky", "search.highlight", "search.share", "search.suggest", "content.code.copy", "navigation.expand", "navigation.instant", "navigation.sections"], "search": "../assets/javascripts/workers/search.b8dbb3d2.min.js", "translations": {"clipboard.copied": "Copied to clipboard", "clipboard.copy": "Copy to clipboard", "search.result.more.one": "1 more on this page", "search.result.more.other": "# more on this page", "search.result.none": "No matching documents", "search.result.one": "1 matching document", "search.result.other": "# matching documents", "search.result.placeholder": "Type to start searching", "search.result.term.missing": "Missing", "select.version": "Select version"}}</script>
+    <script id="__config" type="application/json">{"base": "..", "features": ["navigation.tabs", "navigation.tabs.sticky", "search.highlight", "search.share", "search.suggest", "content.code.copy", "navigation.expand", "navigation.instant", "navigation.sections", "announce.dismiss"], "search": "../assets/javascripts/workers/search.b8dbb3d2.min.js", "translations": {"clipboard.copied": "Copied to clipboard", "clipboard.copy": "Copy to clipboard", "search.result.more.one": "1 more on this page", "search.result.more.other": "# more on this page", "search.result.none": "No matching documents", "search.result.one": "1 matching document", "search.result.other": "# matching documents", "search.result.placeholder": "Type to start searching", "search.result.term.missing": "Missing", "select.version": "Select version"}}</script>
     
     
       <script src="../assets/javascripts/bundle.8fd75fb4.min.js"></script>
diff --git a/site/404.html b/site/404.html
index de653dd..57e81db 100644
--- a/site/404.html
+++ b/site/404.html
@@ -74,11 +74,18 @@
         <aside class="md-banner">
           <div class="md-banner__inner md-grid md-typeset">
             
+              <button class="md-banner__button md-icon" aria-label="Don't show this again">
+                
+                <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M19 6.41 17.59 5 12 10.59 6.41 5 5 6.41 10.59 12 5 17.59 6.41 19 12 13.41 17.59 19 19 17.59 13.41 12 19 6.41Z"/></svg>
+              </button>
+            
             
 📢 Two new full sections are now available: <a href="https://100go.co/5-interface-pollution/">#5: Interface pollution</a> and <a href="https://100go.co/92-false-sharing/">#92: Writing concurrent code that leads to false sharing</a>.
 
           </div>
           
+            <script>var content,el=document.querySelector("[data-md-component=announce]");el&&(content=el.querySelector(".md-typeset"),__md_hash(content.innerHTML)===__md_get("__announce")&&(el.hidden=!0))</script>
+          
         </aside>
       
     </div>
@@ -849,7 +856,7 @@
     </div>
     
     
-    <script id="__config" type="application/json">{"base": "/", "features": ["navigation.tabs", "navigation.tabs.sticky", "search.highlight", "search.share", "search.suggest", "content.code.copy", "navigation.expand", "navigation.instant", "navigation.sections"], "search": "/assets/javascripts/workers/search.b8dbb3d2.min.js", "translations": {"clipboard.copied": "Copied to clipboard", "clipboard.copy": "Copy to clipboard", "search.result.more.one": "1 more on this page", "search.result.more.other": "# more on this page", "search.result.none": "No matching documents", "search.result.one": "1 matching document", "search.result.other": "# matching documents", "search.result.placeholder": "Type to start searching", "search.result.term.missing": "Missing", "select.version": "Select version"}}</script>
+    <script id="__config" type="application/json">{"base": "/", "features": ["navigation.tabs", "navigation.tabs.sticky", "search.highlight", "search.share", "search.suggest", "content.code.copy", "navigation.expand", "navigation.instant", "navigation.sections", "announce.dismiss"], "search": "/assets/javascripts/workers/search.b8dbb3d2.min.js", "translations": {"clipboard.copied": "Copied to clipboard", "clipboard.copy": "Copy to clipboard", "search.result.more.one": "1 more on this page", "search.result.more.other": "# more on this page", "search.result.none": "No matching documents", "search.result.one": "1 matching document", "search.result.other": "# matching documents", "search.result.placeholder": "Type to start searching", "search.result.term.missing": "Missing", "select.version": "Select version"}}</script>
     
     
       <script src="/assets/javascripts/bundle.8fd75fb4.min.js"></script>
diff --git a/site/5-interface-pollution/index.html b/site/5-interface-pollution/index.html
index edf585f..dcdd2c8 100644
--- a/site/5-interface-pollution/index.html
+++ b/site/5-interface-pollution/index.html
@@ -120,11 +120,18 @@
         <aside class="md-banner">
           <div class="md-banner__inner md-grid md-typeset">
             
+              <button class="md-banner__button md-icon" aria-label="Don't show this again">
+                
+                <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M19 6.41 17.59 5 12 10.59 6.41 5 5 6.41 10.59 12 5 17.59 6.41 19 12 13.41 17.59 19 19 17.59 13.41 12 19 6.41Z"/></svg>
+              </button>
+            
             
 📢 Two new full sections are now available: <a href="https://100go.co/5-interface-pollution/">#5: Interface pollution</a> and <a href="https://100go.co/92-false-sharing/">#92: Writing concurrent code that leads to false sharing</a>.
 
           </div>
           
+            <script>var content,el=document.querySelector("[data-md-component=announce]");el&&(content=el.querySelector(".md-typeset"),__md_hash(content.innerHTML)===__md_get("__announce")&&(el.hidden=!0))</script>
+          
         </aside>
       
     </div>
@@ -1338,7 +1345,7 @@
     </div>
     
     
-    <script id="__config" type="application/json">{"base": "..", "features": ["navigation.tabs", "navigation.tabs.sticky", "search.highlight", "search.share", "search.suggest", "content.code.copy", "navigation.expand", "navigation.instant", "navigation.sections"], "search": "../assets/javascripts/workers/search.b8dbb3d2.min.js", "translations": {"clipboard.copied": "Copied to clipboard", "clipboard.copy": "Copy to clipboard", "search.result.more.one": "1 more on this page", "search.result.more.other": "# more on this page", "search.result.none": "No matching documents", "search.result.one": "1 matching document", "search.result.other": "# matching documents", "search.result.placeholder": "Type to start searching", "search.result.term.missing": "Missing", "select.version": "Select version"}}</script>
+    <script id="__config" type="application/json">{"base": "..", "features": ["navigation.tabs", "navigation.tabs.sticky", "search.highlight", "search.share", "search.suggest", "content.code.copy", "navigation.expand", "navigation.instant", "navigation.sections", "announce.dismiss"], "search": "../assets/javascripts/workers/search.b8dbb3d2.min.js", "translations": {"clipboard.copied": "Copied to clipboard", "clipboard.copy": "Copy to clipboard", "search.result.more.one": "1 more on this page", "search.result.more.other": "# more on this page", "search.result.none": "No matching documents", "search.result.one": "1 matching document", "search.result.other": "# matching documents", "search.result.placeholder": "Type to start searching", "search.result.term.missing": "Missing", "select.version": "Select version"}}</script>
     
     
       <script src="../assets/javascripts/bundle.8fd75fb4.min.js"></script>
diff --git a/site/56-concurrency-faster/index.html b/site/56-concurrency-faster/index.html
index 3ce7b76..ac17092 100644
--- a/site/56-concurrency-faster/index.html
+++ b/site/56-concurrency-faster/index.html
@@ -120,11 +120,18 @@
         <aside class="md-banner">
           <div class="md-banner__inner md-grid md-typeset">
             
+              <button class="md-banner__button md-icon" aria-label="Don't show this again">
+                
+                <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M19 6.41 17.59 5 12 10.59 6.41 5 5 6.41 10.59 12 5 17.59 6.41 19 12 13.41 17.59 19 19 17.59 13.41 12 19 6.41Z"/></svg>
+              </button>
+            
             
 📢 Two new full sections are now available: <a href="https://100go.co/5-interface-pollution/">#5: Interface pollution</a> and <a href="https://100go.co/92-false-sharing/">#92: Writing concurrent code that leads to false sharing</a>.
 
           </div>
           
+            <script>var content,el=document.querySelector("[data-md-component=announce]");el&&(content=el.querySelector(".md-typeset"),__md_hash(content.innerHTML)===__md_get("__announce")&&(el.hidden=!0))</script>
+          
         </aside>
       
     </div>
@@ -1249,7 +1256,7 @@
     </div>
     
     
-    <script id="__config" type="application/json">{"base": "..", "features": ["navigation.tabs", "navigation.tabs.sticky", "search.highlight", "search.share", "search.suggest", "content.code.copy", "navigation.expand", "navigation.instant", "navigation.sections"], "search": "../assets/javascripts/workers/search.b8dbb3d2.min.js", "translations": {"clipboard.copied": "Copied to clipboard", "clipboard.copy": "Copy to clipboard", "search.result.more.one": "1 more on this page", "search.result.more.other": "# more on this page", "search.result.none": "No matching documents", "search.result.one": "1 matching document", "search.result.other": "# matching documents", "search.result.placeholder": "Type to start searching", "search.result.term.missing": "Missing", "select.version": "Select version"}}</script>
+    <script id="__config" type="application/json">{"base": "..", "features": ["navigation.tabs", "navigation.tabs.sticky", "search.highlight", "search.share", "search.suggest", "content.code.copy", "navigation.expand", "navigation.instant", "navigation.sections", "announce.dismiss"], "search": "../assets/javascripts/workers/search.b8dbb3d2.min.js", "translations": {"clipboard.copied": "Copied to clipboard", "clipboard.copy": "Copy to clipboard", "search.result.more.one": "1 more on this page", "search.result.more.other": "# more on this page", "search.result.none": "No matching documents", "search.result.one": "1 matching document", "search.result.other": "# matching documents", "search.result.placeholder": "Type to start searching", "search.result.term.missing": "Missing", "select.version": "Select version"}}</script>
     
     
       <script src="../assets/javascripts/bundle.8fd75fb4.min.js"></script>
diff --git a/site/89-benchmarks/index.html b/site/89-benchmarks/index.html
index 092a00c..54ffcf2 100644
--- a/site/89-benchmarks/index.html
+++ b/site/89-benchmarks/index.html
@@ -120,11 +120,18 @@
         <aside class="md-banner">
           <div class="md-banner__inner md-grid md-typeset">
             
+              <button class="md-banner__button md-icon" aria-label="Don't show this again">
+                
+                <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M19 6.41 17.59 5 12 10.59 6.41 5 5 6.41 10.59 12 5 17.59 6.41 19 12 13.41 17.59 19 19 17.59 13.41 12 19 6.41Z"/></svg>
+              </button>
+            
             
 📢 Two new full sections are now available: <a href="https://100go.co/5-interface-pollution/">#5: Interface pollution</a> and <a href="https://100go.co/92-false-sharing/">#92: Writing concurrent code that leads to false sharing</a>.
 
           </div>
           
+            <script>var content,el=document.querySelector("[data-md-component=announce]");el&&(content=el.querySelector(".md-typeset"),__md_hash(content.innerHTML)===__md_get("__announce")&&(el.hidden=!0))</script>
+          
         </aside>
       
     </div>
@@ -1391,7 +1398,7 @@
     </div>
     
     
-    <script id="__config" type="application/json">{"base": "..", "features": ["navigation.tabs", "navigation.tabs.sticky", "search.highlight", "search.share", "search.suggest", "content.code.copy", "navigation.expand", "navigation.instant", "navigation.sections"], "search": "../assets/javascripts/workers/search.b8dbb3d2.min.js", "translations": {"clipboard.copied": "Copied to clipboard", "clipboard.copy": "Copy to clipboard", "search.result.more.one": "1 more on this page", "search.result.more.other": "# more on this page", "search.result.none": "No matching documents", "search.result.one": "1 matching document", "search.result.other": "# matching documents", "search.result.placeholder": "Type to start searching", "search.result.term.missing": "Missing", "select.version": "Select version"}}</script>
+    <script id="__config" type="application/json">{"base": "..", "features": ["navigation.tabs", "navigation.tabs.sticky", "search.highlight", "search.share", "search.suggest", "content.code.copy", "navigation.expand", "navigation.instant", "navigation.sections", "announce.dismiss"], "search": "../assets/javascripts/workers/search.b8dbb3d2.min.js", "translations": {"clipboard.copied": "Copied to clipboard", "clipboard.copy": "Copy to clipboard", "search.result.more.one": "1 more on this page", "search.result.more.other": "# more on this page", "search.result.none": "No matching documents", "search.result.one": "1 matching document", "search.result.other": "# matching documents", "search.result.placeholder": "Type to start searching", "search.result.term.missing": "Missing", "select.version": "Select version"}}</script>
     
     
       <script src="../assets/javascripts/bundle.8fd75fb4.min.js"></script>
diff --git a/site/9-generics/index.html b/site/9-generics/index.html
index 3636cf5..ba5852a 100644
--- a/site/9-generics/index.html
+++ b/site/9-generics/index.html
@@ -120,11 +120,18 @@
         <aside class="md-banner">
           <div class="md-banner__inner md-grid md-typeset">
             
+              <button class="md-banner__button md-icon" aria-label="Don't show this again">
+                
+                <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M19 6.41 17.59 5 12 10.59 6.41 5 5 6.41 10.59 12 5 17.59 6.41 19 12 13.41 17.59 19 19 17.59 13.41 12 19 6.41Z"/></svg>
+              </button>
+            
             
 📢 Two new full sections are now available: <a href="https://100go.co/5-interface-pollution/">#5: Interface pollution</a> and <a href="https://100go.co/92-false-sharing/">#92: Writing concurrent code that leads to false sharing</a>.
 
           </div>
           
+            <script>var content,el=document.querySelector("[data-md-component=announce]");el&&(content=el.querySelector(".md-typeset"),__md_hash(content.innerHTML)===__md_get("__announce")&&(el.hidden=!0))</script>
+          
         </aside>
       
     </div>
@@ -1248,7 +1255,7 @@
     </div>
     
     
-    <script id="__config" type="application/json">{"base": "..", "features": ["navigation.tabs", "navigation.tabs.sticky", "search.highlight", "search.share", "search.suggest", "content.code.copy", "navigation.expand", "navigation.instant", "navigation.sections"], "search": "../assets/javascripts/workers/search.b8dbb3d2.min.js", "translations": {"clipboard.copied": "Copied to clipboard", "clipboard.copy": "Copy to clipboard", "search.result.more.one": "1 more on this page", "search.result.more.other": "# more on this page", "search.result.none": "No matching documents", "search.result.one": "1 matching document", "search.result.other": "# matching documents", "search.result.placeholder": "Type to start searching", "search.result.term.missing": "Missing", "select.version": "Select version"}}</script>
+    <script id="__config" type="application/json">{"base": "..", "features": ["navigation.tabs", "navigation.tabs.sticky", "search.highlight", "search.share", "search.suggest", "content.code.copy", "navigation.expand", "navigation.instant", "navigation.sections", "announce.dismiss"], "search": "../assets/javascripts/workers/search.b8dbb3d2.min.js", "translations": {"clipboard.copied": "Copied to clipboard", "clipboard.copy": "Copy to clipboard", "search.result.more.one": "1 more on this page", "search.result.more.other": "# more on this page", "search.result.none": "No matching documents", "search.result.one": "1 matching document", "search.result.other": "# matching documents", "search.result.placeholder": "Type to start searching", "search.result.term.missing": "Missing", "select.version": "Select version"}}</script>
     
     
       <script src="../assets/javascripts/bundle.8fd75fb4.min.js"></script>
diff --git a/site/92-false-sharing/index.html b/site/92-false-sharing/index.html
index 25cc151..61d791f 100644
--- a/site/92-false-sharing/index.html
+++ b/site/92-false-sharing/index.html
@@ -120,11 +120,18 @@
         <aside class="md-banner">
           <div class="md-banner__inner md-grid md-typeset">
             
+              <button class="md-banner__button md-icon" aria-label="Don't show this again">
+                
+                <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M19 6.41 17.59 5 12 10.59 6.41 5 5 6.41 10.59 12 5 17.59 6.41 19 12 13.41 17.59 19 19 17.59 13.41 12 19 6.41Z"/></svg>
+              </button>
+            
             
 📢 Two new full sections are now available: <a href="https://100go.co/5-interface-pollution/">#5: Interface pollution</a> and <a href="https://100go.co/92-false-sharing/">#92: Writing concurrent code that leads to false sharing</a>.
 
           </div>
           
+            <script>var content,el=document.querySelector("[data-md-component=announce]");el&&(content=el.querySelector(".md-typeset"),__md_hash(content.innerHTML)===__md_get("__announce")&&(el.hidden=!0))</script>
+          
         </aside>
       
     </div>
@@ -1083,7 +1090,7 @@
     </div>
     
     
-    <script id="__config" type="application/json">{"base": "..", "features": ["navigation.tabs", "navigation.tabs.sticky", "search.highlight", "search.share", "search.suggest", "content.code.copy", "navigation.expand", "navigation.instant", "navigation.sections"], "search": "../assets/javascripts/workers/search.b8dbb3d2.min.js", "translations": {"clipboard.copied": "Copied to clipboard", "clipboard.copy": "Copy to clipboard", "search.result.more.one": "1 more on this page", "search.result.more.other": "# more on this page", "search.result.none": "No matching documents", "search.result.one": "1 matching document", "search.result.other": "# matching documents", "search.result.placeholder": "Type to start searching", "search.result.term.missing": "Missing", "select.version": "Select version"}}</script>
+    <script id="__config" type="application/json">{"base": "..", "features": ["navigation.tabs", "navigation.tabs.sticky", "search.highlight", "search.share", "search.suggest", "content.code.copy", "navigation.expand", "navigation.instant", "navigation.sections", "announce.dismiss"], "search": "../assets/javascripts/workers/search.b8dbb3d2.min.js", "translations": {"clipboard.copied": "Copied to clipboard", "clipboard.copy": "Copy to clipboard", "search.result.more.one": "1 more on this page", "search.result.more.other": "# more on this page", "search.result.none": "No matching documents", "search.result.one": "1 matching document", "search.result.other": "# matching documents", "search.result.placeholder": "Type to start searching", "search.result.term.missing": "Missing", "select.version": "Select version"}}</script>
     
     
       <script src="../assets/javascripts/bundle.8fd75fb4.min.js"></script>
diff --git a/site/98-profiling-execution-tracing/index.html b/site/98-profiling-execution-tracing/index.html
index a768b4b..80781e9 100644
--- a/site/98-profiling-execution-tracing/index.html
+++ b/site/98-profiling-execution-tracing/index.html
@@ -120,11 +120,18 @@
         <aside class="md-banner">
           <div class="md-banner__inner md-grid md-typeset">
             
+              <button class="md-banner__button md-icon" aria-label="Don't show this again">
+                
+                <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M19 6.41 17.59 5 12 10.59 6.41 5 5 6.41 10.59 12 5 17.59 6.41 19 12 13.41 17.59 19 19 17.59 13.41 12 19 6.41Z"/></svg>
+              </button>
+            
             
 📢 Two new full sections are now available: <a href="https://100go.co/5-interface-pollution/">#5: Interface pollution</a> and <a href="https://100go.co/92-false-sharing/">#92: Writing concurrent code that leads to false sharing</a>.
 
           </div>
           
+            <script>var content,el=document.querySelector("[data-md-component=announce]");el&&(content=el.querySelector(".md-typeset"),__md_hash(content.innerHTML)===__md_get("__announce")&&(el.hidden=!0))</script>
+          
         </aside>
       
     </div>
@@ -1437,7 +1444,7 @@ world” is executed, which occupies the four CPU cores for approximately 40 ms.
     </div>
     
     
-    <script id="__config" type="application/json">{"base": "..", "features": ["navigation.tabs", "navigation.tabs.sticky", "search.highlight", "search.share", "search.suggest", "content.code.copy", "navigation.expand", "navigation.instant", "navigation.sections"], "search": "../assets/javascripts/workers/search.b8dbb3d2.min.js", "translations": {"clipboard.copied": "Copied to clipboard", "clipboard.copy": "Copy to clipboard", "search.result.more.one": "1 more on this page", "search.result.more.other": "# more on this page", "search.result.none": "No matching documents", "search.result.one": "1 matching document", "search.result.other": "# matching documents", "search.result.placeholder": "Type to start searching", "search.result.term.missing": "Missing", "select.version": "Select version"}}</script>
+    <script id="__config" type="application/json">{"base": "..", "features": ["navigation.tabs", "navigation.tabs.sticky", "search.highlight", "search.share", "search.suggest", "content.code.copy", "navigation.expand", "navigation.instant", "navigation.sections", "announce.dismiss"], "search": "../assets/javascripts/workers/search.b8dbb3d2.min.js", "translations": {"clipboard.copied": "Copied to clipboard", "clipboard.copy": "Copy to clipboard", "search.result.more.one": "1 more on this page", "search.result.more.other": "# more on this page", "search.result.none": "No matching documents", "search.result.one": "1 matching document", "search.result.other": "# matching documents", "search.result.placeholder": "Type to start searching", "search.result.term.missing": "Missing", "select.version": "Select version"}}</script>
     
     
       <script src="../assets/javascripts/bundle.8fd75fb4.min.js"></script>
diff --git a/site/book/index.html b/site/book/index.html
index 90c7fa3..522d9f8 100644
--- a/site/book/index.html
+++ b/site/book/index.html
@@ -118,11 +118,18 @@
         <aside class="md-banner">
           <div class="md-banner__inner md-grid md-typeset">
             
+              <button class="md-banner__button md-icon" aria-label="Don't show this again">
+                
+                <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M19 6.41 17.59 5 12 10.59 6.41 5 5 6.41 10.59 12 5 17.59 6.41 19 12 13.41 17.59 19 19 17.59 13.41 12 19 6.41Z"/></svg>
+              </button>
+            
             
 📢 Two new full sections are now available: <a href="https://100go.co/5-interface-pollution/">#5: Interface pollution</a> and <a href="https://100go.co/92-false-sharing/">#92: Writing concurrent code that leads to false sharing</a>.
 
           </div>
           
+            <script>var content,el=document.querySelector("[data-md-component=announce]");el&&(content=el.querySelector(".md-typeset"),__md_hash(content.innerHTML)===__md_get("__announce")&&(el.hidden=!0))</script>
+          
         </aside>
       
     </div>
@@ -1116,7 +1123,7 @@
     </div>
     
     
-    <script id="__config" type="application/json">{"base": "..", "features": ["navigation.tabs", "navigation.tabs.sticky", "search.highlight", "search.share", "search.suggest", "content.code.copy", "navigation.expand", "navigation.instant", "navigation.sections"], "search": "../assets/javascripts/workers/search.b8dbb3d2.min.js", "translations": {"clipboard.copied": "Copied to clipboard", "clipboard.copy": "Copy to clipboard", "search.result.more.one": "1 more on this page", "search.result.more.other": "# more on this page", "search.result.none": "No matching documents", "search.result.one": "1 matching document", "search.result.other": "# matching documents", "search.result.placeholder": "Type to start searching", "search.result.term.missing": "Missing", "select.version": "Select version"}}</script>
+    <script id="__config" type="application/json">{"base": "..", "features": ["navigation.tabs", "navigation.tabs.sticky", "search.highlight", "search.share", "search.suggest", "content.code.copy", "navigation.expand", "navigation.instant", "navigation.sections", "announce.dismiss"], "search": "../assets/javascripts/workers/search.b8dbb3d2.min.js", "translations": {"clipboard.copied": "Copied to clipboard", "clipboard.copy": "Copy to clipboard", "search.result.more.one": "1 more on this page", "search.result.more.other": "# more on this page", "search.result.none": "No matching documents", "search.result.one": "1 matching document", "search.result.other": "# matching documents", "search.result.placeholder": "Type to start searching", "search.result.term.missing": "Missing", "select.version": "Select version"}}</script>
     
     
       <script src="../assets/javascripts/bundle.8fd75fb4.min.js"></script>
diff --git a/site/chapter-1/index.html b/site/chapter-1/index.html
index 11850ee..0a8fb1d 100644
--- a/site/chapter-1/index.html
+++ b/site/chapter-1/index.html
@@ -120,11 +120,18 @@
         <aside class="md-banner">
           <div class="md-banner__inner md-grid md-typeset">
             
+              <button class="md-banner__button md-icon" aria-label="Don't show this again">
+                
+                <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M19 6.41 17.59 5 12 10.59 6.41 5 5 6.41 10.59 12 5 17.59 6.41 19 12 13.41 17.59 19 19 17.59 13.41 12 19 6.41Z"/></svg>
+              </button>
+            
             
 📢 Two new full sections are now available: <a href="https://100go.co/5-interface-pollution/">#5: Interface pollution</a> and <a href="https://100go.co/92-false-sharing/">#92: Writing concurrent code that leads to false sharing</a>.
 
           </div>
           
+            <script>var content,el=document.querySelector("[data-md-component=announce]");el&&(content=el.querySelector(".md-typeset"),__md_hash(content.innerHTML)===__md_get("__announce")&&(el.hidden=!0))</script>
+          
         </aside>
       
     </div>
@@ -1287,7 +1294,7 @@
     </div>
     
     
-    <script id="__config" type="application/json">{"base": "..", "features": ["navigation.tabs", "navigation.tabs.sticky", "search.highlight", "search.share", "search.suggest", "content.code.copy", "navigation.expand", "navigation.instant", "navigation.sections"], "search": "../assets/javascripts/workers/search.b8dbb3d2.min.js", "translations": {"clipboard.copied": "Copied to clipboard", "clipboard.copy": "Copy to clipboard", "search.result.more.one": "1 more on this page", "search.result.more.other": "# more on this page", "search.result.none": "No matching documents", "search.result.one": "1 matching document", "search.result.other": "# matching documents", "search.result.placeholder": "Type to start searching", "search.result.term.missing": "Missing", "select.version": "Select version"}}</script>
+    <script id="__config" type="application/json">{"base": "..", "features": ["navigation.tabs", "navigation.tabs.sticky", "search.highlight", "search.share", "search.suggest", "content.code.copy", "navigation.expand", "navigation.instant", "navigation.sections", "announce.dismiss"], "search": "../assets/javascripts/workers/search.b8dbb3d2.min.js", "translations": {"clipboard.copied": "Copied to clipboard", "clipboard.copy": "Copy to clipboard", "search.result.more.one": "1 more on this page", "search.result.more.other": "# more on this page", "search.result.none": "No matching documents", "search.result.one": "1 matching document", "search.result.other": "# matching documents", "search.result.placeholder": "Type to start searching", "search.result.term.missing": "Missing", "select.version": "Select version"}}</script>
     
     
       <script src="../assets/javascripts/bundle.8fd75fb4.min.js"></script>
diff --git a/site/community/index.html b/site/community/index.html
index 4fc0663..2c0324e 100644
--- a/site/community/index.html
+++ b/site/community/index.html
@@ -118,11 +118,18 @@
         <aside class="md-banner">
           <div class="md-banner__inner md-grid md-typeset">
             
+              <button class="md-banner__button md-icon" aria-label="Don't show this again">
+                
+                <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M19 6.41 17.59 5 12 10.59 6.41 5 5 6.41 10.59 12 5 17.59 6.41 19 12 13.41 17.59 19 19 17.59 13.41 12 19 6.41Z"/></svg>
+              </button>
+            
             
 📢 Two new full sections are now available: <a href="https://100go.co/5-interface-pollution/">#5: Interface pollution</a> and <a href="https://100go.co/92-false-sharing/">#92: Writing concurrent code that leads to false sharing</a>.
 
           </div>
           
+            <script>var content,el=document.querySelector("[data-md-component=announce]");el&&(content=el.querySelector(".md-typeset"),__md_hash(content.innerHTML)===__md_get("__announce")&&(el.hidden=!0))</script>
+          
         </aside>
       
     </div>
@@ -941,7 +948,7 @@
     </div>
     
     
-    <script id="__config" type="application/json">{"base": "..", "features": ["navigation.tabs", "navigation.tabs.sticky", "search.highlight", "search.share", "search.suggest", "content.code.copy", "navigation.expand", "navigation.instant", "navigation.sections"], "search": "../assets/javascripts/workers/search.b8dbb3d2.min.js", "translations": {"clipboard.copied": "Copied to clipboard", "clipboard.copy": "Copy to clipboard", "search.result.more.one": "1 more on this page", "search.result.more.other": "# more on this page", "search.result.none": "No matching documents", "search.result.one": "1 matching document", "search.result.other": "# matching documents", "search.result.placeholder": "Type to start searching", "search.result.term.missing": "Missing", "select.version": "Select version"}}</script>
+    <script id="__config" type="application/json">{"base": "..", "features": ["navigation.tabs", "navigation.tabs.sticky", "search.highlight", "search.share", "search.suggest", "content.code.copy", "navigation.expand", "navigation.instant", "navigation.sections", "announce.dismiss"], "search": "../assets/javascripts/workers/search.b8dbb3d2.min.js", "translations": {"clipboard.copied": "Copied to clipboard", "clipboard.copy": "Copy to clipboard", "search.result.more.one": "1 more on this page", "search.result.more.other": "# more on this page", "search.result.none": "No matching documents", "search.result.one": "1 matching document", "search.result.other": "# matching documents", "search.result.placeholder": "Type to start searching", "search.result.term.missing": "Missing", "select.version": "Select version"}}</script>
     
     
       <script src="../assets/javascripts/bundle.8fd75fb4.min.js"></script>
diff --git a/site/external/index.html b/site/external/index.html
index fcaf99c..b3e318c 100644
--- a/site/external/index.html
+++ b/site/external/index.html
@@ -120,11 +120,18 @@
         <aside class="md-banner">
           <div class="md-banner__inner md-grid md-typeset">
             
+              <button class="md-banner__button md-icon" aria-label="Don't show this again">
+                
+                <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M19 6.41 17.59 5 12 10.59 6.41 5 5 6.41 10.59 12 5 17.59 6.41 19 12 13.41 17.59 19 19 17.59 13.41 12 19 6.41Z"/></svg>
+              </button>
+            
             
 📢 Two new full sections are now available: <a href="https://100go.co/5-interface-pollution/">#5: Interface pollution</a> and <a href="https://100go.co/92-false-sharing/">#92: Writing concurrent code that leads to false sharing</a>.
 
           </div>
           
+            <script>var content,el=document.querySelector("[data-md-component=announce]");el&&(content=el.querySelector(".md-typeset"),__md_hash(content.innerHTML)===__md_get("__announce")&&(el.hidden=!0))</script>
+          
         </aside>
       
     </div>
@@ -1408,7 +1415,7 @@
     </div>
     
     
-    <script id="__config" type="application/json">{"base": "..", "features": ["navigation.tabs", "navigation.tabs.sticky", "search.highlight", "search.share", "search.suggest", "content.code.copy", "navigation.expand", "navigation.instant", "navigation.sections"], "search": "../assets/javascripts/workers/search.b8dbb3d2.min.js", "translations": {"clipboard.copied": "Copied to clipboard", "clipboard.copy": "Copy to clipboard", "search.result.more.one": "1 more on this page", "search.result.more.other": "# more on this page", "search.result.none": "No matching documents", "search.result.one": "1 matching document", "search.result.other": "# matching documents", "search.result.placeholder": "Type to start searching", "search.result.term.missing": "Missing", "select.version": "Select version"}}</script>
+    <script id="__config" type="application/json">{"base": "..", "features": ["navigation.tabs", "navigation.tabs.sticky", "search.highlight", "search.share", "search.suggest", "content.code.copy", "navigation.expand", "navigation.instant", "navigation.sections", "announce.dismiss"], "search": "../assets/javascripts/workers/search.b8dbb3d2.min.js", "translations": {"clipboard.copied": "Copied to clipboard", "clipboard.copy": "Copy to clipboard", "search.result.more.one": "1 more on this page", "search.result.more.other": "# more on this page", "search.result.none": "No matching documents", "search.result.one": "1 matching document", "search.result.other": "# matching documents", "search.result.placeholder": "Type to start searching", "search.result.term.missing": "Missing", "select.version": "Select version"}}</script>
     
     
       <script src="../assets/javascripts/bundle.8fd75fb4.min.js"></script>
diff --git a/site/index.html b/site/index.html
index 0c60089..f23f7b6 100644
--- a/site/index.html
+++ b/site/index.html
@@ -120,11 +120,18 @@
         <aside class="md-banner">
           <div class="md-banner__inner md-grid md-typeset">
             
+              <button class="md-banner__button md-icon" aria-label="Don't show this again">
+                
+                <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M19 6.41 17.59 5 12 10.59 6.41 5 5 6.41 10.59 12 5 17.59 6.41 19 12 13.41 17.59 19 19 17.59 13.41 12 19 6.41Z"/></svg>
+              </button>
+            
             
 📢 Two new full sections are now available: <a href="https://100go.co/5-interface-pollution/">#5: Interface pollution</a> and <a href="https://100go.co/92-false-sharing/">#92: Writing concurrent code that leads to false sharing</a>.
 
           </div>
           
+            <script>var content,el=document.querySelector("[data-md-component=announce]");el&&(content=el.querySelector(".md-typeset"),__md_hash(content.innerHTML)===__md_get("__announce")&&(el.hidden=!0))</script>
+          
         </aside>
       
     </div>
@@ -4961,7 +4968,7 @@ the use case. However, we should see the two options as complementary. </p>
     </div>
     
     
-    <script id="__config" type="application/json">{"base": ".", "features": ["navigation.tabs", "navigation.tabs.sticky", "search.highlight", "search.share", "search.suggest", "content.code.copy", "navigation.expand", "navigation.instant", "navigation.sections"], "search": "assets/javascripts/workers/search.b8dbb3d2.min.js", "translations": {"clipboard.copied": "Copied to clipboard", "clipboard.copy": "Copy to clipboard", "search.result.more.one": "1 more on this page", "search.result.more.other": "# more on this page", "search.result.none": "No matching documents", "search.result.one": "1 matching document", "search.result.other": "# matching documents", "search.result.placeholder": "Type to start searching", "search.result.term.missing": "Missing", "select.version": "Select version"}}</script>
+    <script id="__config" type="application/json">{"base": ".", "features": ["navigation.tabs", "navigation.tabs.sticky", "search.highlight", "search.share", "search.suggest", "content.code.copy", "navigation.expand", "navigation.instant", "navigation.sections", "announce.dismiss"], "search": "assets/javascripts/workers/search.b8dbb3d2.min.js", "translations": {"clipboard.copied": "Copied to clipboard", "clipboard.copy": "Copy to clipboard", "search.result.more.one": "1 more on this page", "search.result.more.other": "# more on this page", "search.result.none": "No matching documents", "search.result.one": "1 matching document", "search.result.other": "# matching documents", "search.result.placeholder": "Type to start searching", "search.result.term.missing": "Missing", "select.version": "Select version"}}</script>
     
     
       <script src="assets/javascripts/bundle.8fd75fb4.min.js"></script>
diff --git a/site/ja/index.html b/site/ja/index.html
index bcbf4e6..18a05f3 100644
--- a/site/ja/index.html
+++ b/site/ja/index.html
@@ -116,11 +116,18 @@
         <aside class="md-banner">
           <div class="md-banner__inner md-grid md-typeset">
             
+              <button class="md-banner__button md-icon" aria-label="Don't show this again">
+                
+                <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M19 6.41 17.59 5 12 10.59 6.41 5 5 6.41 10.59 12 5 17.59 6.41 19 12 13.41 17.59 19 19 17.59 13.41 12 19 6.41Z"/></svg>
+              </button>
+            
             
 📢 Two new full sections are now available: <a href="https://100go.co/5-interface-pollution/">#5: Interface pollution</a> and <a href="https://100go.co/92-false-sharing/">#92: Writing concurrent code that leads to false sharing</a>.
 
           </div>
           
+            <script>var content,el=document.querySelector("[data-md-component=announce]");el&&(content=el.querySelector(".md-typeset"),__md_hash(content.innerHTML)===__md_get("__announce")&&(el.hidden=!0))</script>
+          
         </aside>
       
     </div>
@@ -3665,7 +3672,7 @@
     </div>
     
     
-    <script id="__config" type="application/json">{"base": "..", "features": ["navigation.tabs", "navigation.tabs.sticky", "search.highlight", "search.share", "search.suggest", "content.code.copy", "navigation.expand", "navigation.instant", "navigation.sections"], "search": "../assets/javascripts/workers/search.b8dbb3d2.min.js", "translations": {"clipboard.copied": "Copied to clipboard", "clipboard.copy": "Copy to clipboard", "search.result.more.one": "1 more on this page", "search.result.more.other": "# more on this page", "search.result.none": "No matching documents", "search.result.one": "1 matching document", "search.result.other": "# matching documents", "search.result.placeholder": "Type to start searching", "search.result.term.missing": "Missing", "select.version": "Select version"}}</script>
+    <script id="__config" type="application/json">{"base": "..", "features": ["navigation.tabs", "navigation.tabs.sticky", "search.highlight", "search.share", "search.suggest", "content.code.copy", "navigation.expand", "navigation.instant", "navigation.sections", "announce.dismiss"], "search": "../assets/javascripts/workers/search.b8dbb3d2.min.js", "translations": {"clipboard.copied": "Copied to clipboard", "clipboard.copy": "Copy to clipboard", "search.result.more.one": "1 more on this page", "search.result.more.other": "# more on this page", "search.result.none": "No matching documents", "search.result.one": "1 matching document", "search.result.other": "# matching documents", "search.result.placeholder": "Type to start searching", "search.result.term.missing": "Missing", "select.version": "Select version"}}</script>
     
     
       <script src="../assets/javascripts/bundle.8fd75fb4.min.js"></script>
diff --git a/site/jobs/index.html b/site/jobs/index.html
index 0cab6fd..c2f4d01 100644
--- a/site/jobs/index.html
+++ b/site/jobs/index.html
@@ -116,11 +116,18 @@
         <aside class="md-banner">
           <div class="md-banner__inner md-grid md-typeset">
             
+              <button class="md-banner__button md-icon" aria-label="Don't show this again">
+                
+                <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M19 6.41 17.59 5 12 10.59 6.41 5 5 6.41 10.59 12 5 17.59 6.41 19 12 13.41 17.59 19 19 17.59 13.41 12 19 6.41Z"/></svg>
+              </button>
+            
             
 📢 Two new full sections are now available: <a href="https://100go.co/5-interface-pollution/">#5: Interface pollution</a> and <a href="https://100go.co/92-false-sharing/">#92: Writing concurrent code that leads to false sharing</a>.
 
           </div>
           
+            <script>var content,el=document.querySelector("[data-md-component=announce]");el&&(content=el.querySelector(".md-typeset"),__md_hash(content.innerHTML)===__md_get("__announce")&&(el.hidden=!0))</script>
+          
         </aside>
       
     </div>
@@ -923,7 +930,7 @@
     </div>
     
     
-    <script id="__config" type="application/json">{"base": "..", "features": ["navigation.tabs", "navigation.tabs.sticky", "search.highlight", "search.share", "search.suggest", "content.code.copy", "navigation.expand", "navigation.instant", "navigation.sections"], "search": "../assets/javascripts/workers/search.b8dbb3d2.min.js", "translations": {"clipboard.copied": "Copied to clipboard", "clipboard.copy": "Copy to clipboard", "search.result.more.one": "1 more on this page", "search.result.more.other": "# more on this page", "search.result.none": "No matching documents", "search.result.one": "1 matching document", "search.result.other": "# matching documents", "search.result.placeholder": "Type to start searching", "search.result.term.missing": "Missing", "select.version": "Select version"}}</script>
+    <script id="__config" type="application/json">{"base": "..", "features": ["navigation.tabs", "navigation.tabs.sticky", "search.highlight", "search.share", "search.suggest", "content.code.copy", "navigation.expand", "navigation.instant", "navigation.sections", "announce.dismiss"], "search": "../assets/javascripts/workers/search.b8dbb3d2.min.js", "translations": {"clipboard.copied": "Copied to clipboard", "clipboard.copy": "Copy to clipboard", "search.result.more.one": "1 more on this page", "search.result.more.other": "# more on this page", "search.result.none": "No matching documents", "search.result.one": "1 matching document", "search.result.other": "# matching documents", "search.result.placeholder": "Type to start searching", "search.result.term.missing": "Missing", "select.version": "Select version"}}</script>
     
     
       <script src="../assets/javascripts/bundle.8fd75fb4.min.js"></script>
diff --git a/site/sitemap.xml.gz b/site/sitemap.xml.gz
index 45496d5..43b4d61 100644
Binary files a/site/sitemap.xml.gz and b/site/sitemap.xml.gz differ
diff --git a/site/zh/index.html b/site/zh/index.html
index 45ce6f5..809381b 100644
--- a/site/zh/index.html
+++ b/site/zh/index.html
@@ -116,11 +116,18 @@
         <aside class="md-banner">
           <div class="md-banner__inner md-grid md-typeset">
             
+              <button class="md-banner__button md-icon" aria-label="Don't show this again">
+                
+                <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M19 6.41 17.59 5 12 10.59 6.41 5 5 6.41 10.59 12 5 17.59 6.41 19 12 13.41 17.59 19 19 17.59 13.41 12 19 6.41Z"/></svg>
+              </button>
+            
             
 📢 Two new full sections are now available: <a href="https://100go.co/5-interface-pollution/">#5: Interface pollution</a> and <a href="https://100go.co/92-false-sharing/">#92: Writing concurrent code that leads to false sharing</a>.
 
           </div>
           
+            <script>var content,el=document.querySelector("[data-md-component=announce]");el&&(content=el.querySelector(".md-typeset"),__md_hash(content.innerHTML)===__md_get("__announce")&&(el.hidden=!0))</script>
+          
         </aside>
       
     </div>
@@ -2385,7 +2392,7 @@
     </div>
     
     
-    <script id="__config" type="application/json">{"base": "..", "features": ["navigation.tabs", "navigation.tabs.sticky", "search.highlight", "search.share", "search.suggest", "content.code.copy", "navigation.expand", "navigation.instant", "navigation.sections"], "search": "../assets/javascripts/workers/search.b8dbb3d2.min.js", "translations": {"clipboard.copied": "Copied to clipboard", "clipboard.copy": "Copy to clipboard", "search.result.more.one": "1 more on this page", "search.result.more.other": "# more on this page", "search.result.none": "No matching documents", "search.result.one": "1 matching document", "search.result.other": "# matching documents", "search.result.placeholder": "Type to start searching", "search.result.term.missing": "Missing", "select.version": "Select version"}}</script>
+    <script id="__config" type="application/json">{"base": "..", "features": ["navigation.tabs", "navigation.tabs.sticky", "search.highlight", "search.share", "search.suggest", "content.code.copy", "navigation.expand", "navigation.instant", "navigation.sections", "announce.dismiss"], "search": "../assets/javascripts/workers/search.b8dbb3d2.min.js", "translations": {"clipboard.copied": "Copied to clipboard", "clipboard.copy": "Copy to clipboard", "search.result.more.one": "1 more on this page", "search.result.more.other": "# more on this page", "search.result.none": "No matching documents", "search.result.one": "1 matching document", "search.result.other": "# matching documents", "search.result.placeholder": "Type to start searching", "search.result.term.missing": "Missing", "select.version": "Select version"}}</script>
     
     
       <script src="../assets/javascripts/bundle.8fd75fb4.min.js"></script>