diff --git a/packages/epo-react-lib/package.json b/packages/epo-react-lib/package.json
index 355341bd..9d2fb892 100644
--- a/packages/epo-react-lib/package.json
+++ b/packages/epo-react-lib/package.json
@@ -1,7 +1,7 @@
 {
   "name": "@rubin-epo/epo-react-lib",
   "description": "Rubin Observatory Education & Public Outreach team React UI library.",
-  "version": "2.0.3",
+  "version": "2.0.4",
   "author": "Rubin EPO",
   "license": "MIT",
   "homepage": "https://lsst-epo.github.io/epo-react-lib",
diff --git a/packages/epo-react-lib/src/form/HorizontalSlider/HorizontalSlider.tsx b/packages/epo-react-lib/src/form/HorizontalSlider/HorizontalSlider.tsx
index 8edc8ab8..4c5f4ff0 100644
--- a/packages/epo-react-lib/src/form/HorizontalSlider/HorizontalSlider.tsx
+++ b/packages/epo-react-lib/src/form/HorizontalSlider/HorizontalSlider.tsx
@@ -1,13 +1,12 @@
-import { isColorTransparent } from "@/lib/utils";
+import { isColorTransparent, isStyleSupported } from "@/lib/utils";
 import { useState, FunctionComponent } from "react";
+import { ReactSliderProps } from "react-slider";
 import * as Styled from "./styles";
 
 type SliderValue = number | readonly number[];
 
-type BaseProps = {
-  min?: number;
-  max?: number;
-  step?: number;
+interface BaseProps
+  extends Pick<ReactSliderProps, "min" | "max" | "step" | "className"> {
   label: string;
   minLabel?: string;
   maxLabel?: string;
@@ -15,16 +14,17 @@ type BaseProps = {
   color?: string;
   darkMode?: boolean;
   isDisabled?: boolean;
-  className?: string;
-};
+}
 
 interface SingleSliderProps extends BaseProps {
   value: number;
+  defaultValue?: number;
   onChangeCallback: (value: number, label: string) => void;
 }
 
 interface RangedSliderProps extends BaseProps {
   value: number[];
+  defaultValue?: number[];
   onChangeCallback: (value: number[], label: string) => void;
 }
 
@@ -35,6 +35,7 @@ const HorizontalSlider: FunctionComponent<HorizontalSliderProps> = ({
   max = 100,
   step = 1,
   value,
+  defaultValue,
   onChangeCallback,
   label,
   minLabel,
@@ -55,21 +56,25 @@ const HorizontalSlider: FunctionComponent<HorizontalSliderProps> = ({
 
   const getValidColor = (color?: string) => {
     const validColor =
-      color && CSS.supports("color", color) && !isColorTransparent(color)
+      color && isStyleSupported("color", color) && !isColorTransparent(color)
         ? color
         : undefined;
 
     return isDisabled ? "var(--neutral60, #6a6e6e)" : validColor;
   };
 
-  const Track = (props: any, state: { index: number; value: SliderValue }) => {
+  const Track = (props: any, state: { index: number }) => {
     const { index } = state;
+    const { key, ...other } = props;
     const hasColor =
       (hasDoubleHandles && index === 1) || (!hasDoubleHandles && index === 0);
     const trackColor = getValidColor(color);
-
     return (
-      <Styled.Track color={hasColor ? trackColor : "transparent"} {...props} />
+      <Styled.Track
+        color={hasColor ? trackColor : "transparent"}
+        key={key}
+        {...other}
+      />
     );
   };
 
@@ -77,14 +82,15 @@ const HorizontalSlider: FunctionComponent<HorizontalSliderProps> = ({
     props: any,
     state: { index: number; value: SliderValue; valueNow: number }
   ) => {
+    const { key, ...other } = props;
     const { valueNow } = state;
     const thumbColor = getValidColor(color);
 
     return (
-      <Styled.ThumbContainer {...{ ...props }}>
+      <Styled.ThumbContainer key={key} {...other}>
         <Styled.Thumb {...{ color: thumbColor, $isDisabled: isDisabled }} />
         <Styled.ThumbLabel
-          {...{ $showThumbLabels: showThumbLabels, $darkMode: darkMode }}
+          style={{ "--thumb-label-opacity": showThumbLabels ? 1 : 0 }}
         >
           {valueNow}
         </Styled.ThumbLabel>
@@ -96,19 +102,18 @@ const HorizontalSlider: FunctionComponent<HorizontalSliderProps> = ({
   const maxLabelId = `${label}-max-label`;
 
   return (
-    <Styled.HorizontalSliderContainer {...{ className }}>
+    <Styled.HorizontalSliderContainer
+      data-theme={darkMode ? "dark" : "light"}
+      {...{ className }}
+    >
       {minLabel || maxLabel ? (
         <Styled.TrackLabels>
-          <Styled.Label id={minLabelId} {...{ $darkMode: darkMode }}>
-            {minLabel}
-          </Styled.Label>
-          <Styled.Label id={maxLabelId} {...{ $darkMode: darkMode }}>
-            {maxLabel}
-          </Styled.Label>
+          <Styled.Label id={minLabelId}>{minLabel}</Styled.Label>
+          <Styled.Label id={maxLabelId}>{maxLabel}</Styled.Label>
         </Styled.TrackLabels>
       ) : null}
       <Styled.HorizontalSlider
-        {...{ min, max, step, value, showThumbLabels }}
+        {...{ defaultValue, min, max, step, value, showThumbLabels }}
         onChange={() => {
           setShowThumbLabels(true);
         }}
diff --git a/packages/epo-react-lib/src/form/HorizontalSlider/styles.ts b/packages/epo-react-lib/src/form/HorizontalSlider/styles.ts
index c7597791..30db396e 100644
--- a/packages/epo-react-lib/src/form/HorizontalSlider/styles.ts
+++ b/packages/epo-react-lib/src/form/HorizontalSlider/styles.ts
@@ -8,6 +8,16 @@ const thumbBorder = 4;
 const thumbHeight = 14;
 
 export const HorizontalSliderContainer = styled.div`
+  --slider-color: inherit;
+  --slider-border-color: var(--blue20, #c7d4f4);
+  --slider-background-color: var(--neutral10, #f5f5f5);
+
+  &[data-theme="dark"] {
+    --slider-color: var(--white, #fff);
+    --slider-border-color: var(--white, #fff);
+    --slider-background-color: var(--neutral80, #404040);
+  }
+
   display: flex;
   flex-flow: column nowrap;
   padding-bottom: 16px;
@@ -21,20 +31,19 @@ export const TrackLabels = styled.div`
   padding: 0 3px 6px;
 `;
 
-export const Label = styled.div<{ $darkMode: boolean }>`
+export const Label = styled.div`
   box-sizing: border-box;
   font-size: 14px;
   font-weight: bold;
   line-height: 1.6;
-  color: ${({ $darkMode }) =>
-    $darkMode ? css`var(--white, #fff)` : css`inherit`};
+  color: var(--slider-color);
 `;
 
-export const ThumbLabel = styled.span<{
-  $showThumbLabels: boolean;
-  $darkMode: boolean;
-}>`
+export const ThumbLabel = styled.span`
+  background-color: var(--slider-background-color);
+  border: 1px solid var(--slider-border-color);
   box-sizing: border-box;
+  color: var(--slider-color);
   position: absolute;
   top: calc(100% + ${thumbBorder}px);
   padding: 5px;
@@ -43,22 +52,9 @@ export const ThumbLabel = styled.span<{
   text-align: center;
   line-height: 1.35;
   border-radius: 5px;
-  opacity: ${({ $showThumbLabels }) => ($showThumbLabels ? 1 : 0)};
+  opacity: var(--thumb-label-opacity, 0);
   transition: opacity 0.4s ease-in-out;
   user-select: none;
-
-  ${({ $darkMode }) =>
-    $darkMode
-      ? css`
-          border: 1px solid var(--white);
-          background-color: var(--neutral80);
-          color: var(--white, #fff);
-        `
-      : css`
-          border: 1px solid var(--blue20);
-          background-color: var(--neutral10);
-          color: var(--black, #000);
-        `}
 `;
 
 export const ThumbContainer = styled.div`
diff --git a/packages/epo-react-lib/src/lib/utils.ts b/packages/epo-react-lib/src/lib/utils.ts
index 63f3318c..2cf30dae 100644
--- a/packages/epo-react-lib/src/lib/utils.ts
+++ b/packages/epo-react-lib/src/lib/utils.ts
@@ -68,3 +68,33 @@ export const isColorTransparent = (color: string) => {
 
   return false;
 };
+
+export function isStyleSupported(prop: string, value: string): boolean {
+  // If no value is supplied, use "inherit"
+  value = arguments.length === 2 ? value : "inherit";
+  // Try the native standard method first
+  if ("CSS" in window && "supports" in window.CSS) {
+    return window.CSS.supports(prop, value);
+  }
+  // Check Opera's native method
+  if ("supportsCSS" in window) {
+    return (window.supportsCSS as (property: string, value: string) => boolean)(
+      prop,
+      value
+    );
+  }
+  // Convert to camel-case for DOM interactions
+  const camel = prop.replace(/-([a-z]|[0-9])/gi, function (all, letter) {
+    return (letter + "").toUpperCase();
+  });
+  // Create test element
+  const el = document.createElement("div");
+  // Check if the property is supported
+  const support = camel in el.style;
+  // Assign the property and value to invoke
+  // the CSS interpreter
+  el.style.cssText = prop + ":" + value;
+  // Ensure both the property and value are
+  // supported and return
+  return support && el.style[camel as any] !== "";
+}