diff --git a/_layouts/default.html b/_layouts/default.html
index 1f37bf5..13d96e4 100644
--- a/_layouts/default.html
+++ b/_layouts/default.html
@@ -15,7 +15,7 @@
 
     <link href="/stylesheets/default.css" rel="stylesheet">
     <script src="/js/load.js"></script>
-    <script src="/js/button.js" defer></script>
+    <script src="/js/after.js" defer></script>
     {% seo title=false %}
   </head>
 
@@ -50,6 +50,22 @@ <h5><i class="bi bi-brightness-high-fill" style="vertical-align: -0.125em"></i><
       </nav>
     </header>
 
+    <div class="modal" tabindex="-1" id="brightnessModal">
+      <div class="modal-dialog">
+        <div class="modal-content">
+          <div class="modal-header">
+            <h5 class="modal-title">Brightness Slider</h5>
+            <button type="button" class="btn-close" data-bs-dismiss="modal" aria-label="Close"></button>
+          </div>
+          <div class="modal-body" style="text-align: center;">
+            <label for="brightnessRange" style="vertical-align: 0.30em; padding-right: 5px;">Dark</label>
+            <input type="range" min="0" max="100" value="100" class="slider" id="brightnessRange">
+            <label for="brightnessRange" style="vertical-align: 0.30em; padding-left: 5px;">Bright</label>
+          </div>
+        </div>
+      </div>
+    </div>
+
     <main class="page-wrapper" style="margin: 25px;">
       {{ content }}
     </main>
diff --git a/js/button.js b/js/after.js
similarity index 50%
rename from js/button.js
rename to js/after.js
index 5f3c061..c861f5a 100644
--- a/js/button.js
+++ b/js/after.js
@@ -1,4 +1,8 @@
-document.getElementById("modeButton").addEventListener("click", () => {
+document.getElementById("modeButton").addEventListener("click", (event) => {
+    if (event.ctrlKey) {
+        new bootstrap.Modal(document.getElementById("brightnessModal")).show();
+        return;
+    }
     let attribute = "data-bs-theme";
     let currentState = document.documentElement.getAttribute(attribute);
     let newState = currentState === "light" ? "dark" : "light";
@@ -6,3 +10,6 @@ document.getElementById("modeButton").addEventListener("click", () => {
 
     document.documentElement.setAttribute(attribute, newState);
 });
+
+let brightnessSlider = document.getElementById("brightnessRange");
+brightnessSlider.addEventListener("input", (event) => { document.documentElement.style.filter = `brightness(${event.target.value / 100})` });