diff --git a/sim/public/sim.css b/sim/public/sim.css
deleted file mode 100644
index 1df7a7cf..00000000
--- a/sim/public/sim.css
+++ /dev/null
@@ -1,86 +0,0 @@
-svg.sim {
-    margin-bottom:1em;
-}
-.sim-button {
-    pointer-events: none;    
-}
-
-.sim-button-outer:hover {
-    stroke:grey;
-    stroke-width: 3px;
-}
-
-.sim-pin:hover {
-    stroke:#D4AF37;
-    stroke-width:2px;
-}
-
-.sim-pin-touch.touched:hover {
-    stroke:darkorange;
-}
-
-.sim-led-back:hover {
-    stroke:#a0a0a0;
-    stroke-width:3px;
-}
-.sim-led:hover {
-    stroke:#ff7f7f;
-    stroke-width:3px;
-}
-
-.sim-systemled {
-    fill:#333;
-    stroke:#555;
-    stroke-width: 1px;
-}
-
-.sim-light-level-button {
-    stroke:#fff;
-    stroke-width: 3px;
-}
-
-.sim-antenna {
-    stroke:#555;
-    stroke-width: 2px;
-}
-
-.sim-text {
-  font-family:monospace;
-  font-size:25px;
-  fill:#fff;
-  pointer-events: none;
-}
-
-.sim-text-pin {
-  font-family:monospace;
-  font-size:20px;
-  fill:#fff;
-  pointer-events: none;
-}
-
-.sim-thermometer {
-    stroke:#aaa;
-    stroke-width: 3px;
-}
-
-/* animations */
-.sim-flash {
-    animation-name: sim-flash-animation;
-    animation-duration: 0.1s;
-}
-
-@keyframes sim-flash-animation {  
-    from { fill: yellow; }
-    to   { fill: default; }
-}
-
-.sim-flash-stroke {
-    animation-name: sim-flash-stroke-animation;
-    animation-duration: 0.4s;
-    animation-timing-function: ease-in;
-}
-
-@keyframes sim-flash-stroke-animation {  
-    from { stroke: yellow; }
-    to   { stroke: default; }
-}
\ No newline at end of file
diff --git a/sim/public/simulator.html b/sim/public/simulator.html
index 52ea14d2..7c26aed6 100644
--- a/sim/public/simulator.html
+++ b/sim/public/simulator.html
@@ -4,7 +4,6 @@
 <head>
     <meta charset="utf-8">
     <title>microbit simulator</title>
-    <link rel="stylesheet" type="text/css" href="./sim.css">
     <style>
         body {
             background: transparent;
diff --git a/sim/simsvg.ts b/sim/simsvg.ts
index bde7574b..46be1e02 100644
--- a/sim/simsvg.ts
+++ b/sim/simsvg.ts
@@ -162,6 +162,7 @@ namespace ks.rt.micro_bit {
     export class MicrobitBoardSvg
     {
         public element : SVGSVGElement;
+        private style: SVGStyleElement;
         private defs : SVGDefsElement;
         private g: SVGElement;
         
@@ -459,6 +460,99 @@ namespace ks.rt.micro_bit {
                 "class":"sim",
                 "x": "0px",
                 "y": "0px"});
+            this.style = <SVGStyleElement>Svg.child(this.element, "style", {});
+            this.style.textContent = `
+
+svg.sim {
+    margin-bottom:1em;
+}
+.sim-button {
+    pointer-events: none;    
+}
+
+.sim-button-outer:hover {
+    stroke:grey;
+    stroke-width: 3px;
+}
+
+.sim-pin:hover {
+    stroke:#D4AF37;
+    stroke-width:2px;
+}
+
+.sim-pin-touch.touched:hover {
+    stroke:darkorange;
+}
+
+.sim-led-back:hover {
+    stroke:#a0a0a0;
+    stroke-width:3px;
+}
+.sim-led:hover {
+    stroke:#ff7f7f;
+    stroke-width:3px;
+}
+
+.sim-systemled {
+    fill:#333;
+    stroke:#555;
+    stroke-width: 1px;
+}
+
+.sim-light-level-button {
+    stroke:#fff;
+    stroke-width: 3px;
+}
+
+.sim-antenna {
+    stroke:#555;
+    stroke-width: 2px;
+}
+
+.sim-text {
+  font-family:monospace;
+  font-size:25px;
+  fill:#fff;
+  pointer-events: none;
+}
+
+.sim-text-pin {
+  font-family:monospace;
+  font-size:20px;
+  fill:#fff;
+  pointer-events: none;
+}
+
+.sim-thermometer {
+    stroke:#aaa;
+    stroke-width: 3px;
+}
+
+/* animations */
+.sim-flash {
+    animation-name: sim-flash-animation;
+    animation-duration: 0.1s;
+}
+
+@keyframes sim-flash-animation {  
+    from { fill: yellow; }
+    to   { fill: default; }
+}
+
+.sim-flash-stroke {
+    animation-name: sim-flash-stroke-animation;
+    animation-duration: 0.4s;
+    animation-timing-function: ease-in;
+}
+
+@keyframes sim-flash-stroke-animation {  
+    from { stroke: yellow; }
+    to   { stroke: default; }
+}
+
+            `;
+                
+                
             this.defs = <SVGDefsElement>Svg.child(this.element, "defs", {});
             this.g = Svg.elt("g");
             this.element.appendChild(this.g);
