diff --git a/ui/shared/power/brightness_slider.js b/ui/shared/power/brightness_slider.js
index 317da0e..78ae1f5 100644
--- a/ui/shared/power/brightness_slider.js
+++ b/ui/shared/power/brightness_slider.js
@@ -15,10 +15,6 @@ import {
   keyboardBrightness,
 } from "beaver://shared/power/brightness.js";
 
-// Never let the screen go fully dark from this control: the user would have no
-// way to see the UI to turn it back up.
-const MIN_PERCENT = 5;
-
 export class BrightnessSlider extends LitElement {
   // Pointer currently captured for a drag, or null.
   #pointerId = null;
@@ -30,6 +26,9 @@ export class BrightnessSlider extends LitElement {
   // Either screenBrightness or keyboardBrightness, according to the 'kind' property.
   #device = null;
 
+  // Never let the screen go fully dark from this control, but allow 0 for keyboard lights.
+  #minPercent = 5;
+
   static properties = {
     percent: { type: Number },
     kind: { type: String },
@@ -127,7 +126,7 @@ export class BrightnessSlider extends LitElement {
 
   constructor() {
     super();
-    this.percent = MIN_PERCENT;
+    this.percent = this.#minPercent;
     // Hidden until a backlight is found, so shells can mount us unconditionally.
     this.hidden = true;
   }
@@ -145,6 +144,7 @@ export class BrightnessSlider extends LitElement {
   async #init() {
     if (this.kind == "keyboard") {
       this.#device = keyboardBrightness;
+      this.#minPercent = 0;
     } else {
       this.#device = screenBrightness;
     }
@@ -179,7 +179,7 @@ export class BrightnessSlider extends LitElement {
     }
     const ratio = (event.clientX - rect.left) / rect.width;
     const percent = Math.round(
-      Math.min(100, Math.max(MIN_PERCENT, ratio * 100)),
+      Math.min(100, Math.max(this.#minPercent, ratio * 100)),
     );
     if (percent === this.percent) {
       return;
@@ -255,7 +255,7 @@ export class BrightnessSlider extends LitElement {
           role="slider"
           tabindex="0"
           aria-label="Screen brightness"
-          aria-valuemin="${MIN_PERCENT}"
+          aria-valuemin="${this.#minPercent}"
           aria-valuemax="100"
           aria-valuenow="${this.percent}"
           @pointerdown=${this.#onPointerDown}
@@ -287,7 +287,10 @@ export class BrightnessSlider extends LitElement {
       return;
     }
     event.preventDefault();
-    this.percent = Math.min(100, Math.max(MIN_PERCENT, this.percent + step));
+    this.percent = Math.min(
+      100,
+      Math.max(this.#minPercent, this.percent + step),
+    );
     this.#device.set(this.percent);
   };
 }