diff --git a/src/basic.test.ts b/src/basic.test.ts
index 5dba863..e476abb 100644
--- a/src/basic.test.ts
+++ b/src/basic.test.ts
@@ -98,7 +98,7 @@ describe("size", () => {
       size: "2x",
     });
     const style = getComputedStyle(getFa());
-    expect(style["font-size"]).toBe("2em");
+    expect(style.getPropertyValue("font-size")).toBe("2em");
   });
 
   test("lg", async () => {
diff --git a/src/layers.test.ts b/src/layers.test.ts
index 829e566..eb5adaf 100644
--- a/src/layers.test.ts
+++ b/src/layers.test.ts
@@ -56,14 +56,16 @@ test("basic", async () => {
 
   expect(getFaLayersText("b").getAttribute("id")).toBe("b");
   expect(getFaLayersText("b").getAttribute("class")).toContain("class-b");
-  expect(getComputedStyle(getFaLayersText("b").querySelector("span"))["color"]).toBe(
+  expect(getComputedStyle(getFaLayersText("b").querySelector("span")!)["color"]).toBe(
     "rgb(0, 0, 255)",
   );
 });
 
 test("color", async () => {
   mountFaLayers({}, { color: "red" });
-  expect(getComputedStyle(getFaLayersText().querySelector("span"))["color"]).toBe("rgb(255, 0, 0)");
+  expect(getComputedStyle(getFaLayersText().querySelector("span")!)["color"]).toBe(
+    "rgb(255, 0, 0)",
+  );
   mountFaLayers({}, { color: undefined });
   expect(getFaLayersText().querySelector("span")?.getAttribute("style")).not.toContain("color:red");
 });
@@ -80,9 +82,9 @@ describe("size", () => {
     mountFaLayers({ size: "2x" }, { size: "2x" });
 
     const style = getComputedStyle(getFaLayers());
-    const styleText = getComputedStyle(getFaLayersText().querySelector("span"));
-    expect(style["font-size"]).toBe("2em");
-    expect(styleText["font-size"]).toBe("2em");
+    const styleText = getComputedStyle(getFaLayersText().querySelector("span")!);
+    expect(style.getPropertyValue("font-size")).toBe("2em");
+    expect(styleText.getPropertyValue("font-size")).toBe("2em");
   });
 
   test("lg", async () => {
diff --git a/src/lib/fa.svelte b/src/lib/fa.svelte
index 17b551d..4d1d50c 100644
--- a/src/lib/fa.svelte
+++ b/src/lib/fa.svelte
@@ -31,7 +31,7 @@
   export let secondaryOpacity: number | string = 0.4;
   export let swapOpacity = false;
 
-  let svgElement: HTMLElement;
+  let svgElement: HTMLElement | SVGElement;
   $: svgElement && size && setCutomFontSize(svgElement, size);
 
   $: i = (icon && icon.icon) || [0, 0, "", [], ""];
diff --git a/src/lib/utils.ts b/src/lib/utils.ts
index 3803edc..b01fa63 100644
--- a/src/lib/utils.ts
+++ b/src/lib/utils.ts
@@ -1,8 +1,10 @@
-export function setCutomFontSize(element: HTMLElement, size: IconSize | ""): void {
-  if (size && size !== "lg" && size !== "sm" && size !== "xs" && size !== "") {
+import type { IconSize } from "./types.js";
+
+export function setCutomFontSize(element: HTMLElement | SVGElement, size: IconSize | ""): void {
+  if (size && size !== "lg" && size !== "sm" && size !== "xs") {
     element.style.fontSize = size.replace("x", "em");
   } else {
-    element.style.fontSize = undefined;
+    element.style.fontSize = "";
   }
 }