diff --git a/src/builtins.ts b/src/builtins.ts
index 7caf2dc..ab473c1 100644
--- a/src/builtins.ts
+++ b/src/builtins.ts
@@ -4,7 +4,7 @@ const measureCanvas = document.createElement('canvas');
 const measureCtx = measureCanvas.getContext('2d')!;
 if (!measureCtx)
     throw new Error('Failed to create canvas');
-measureCtx.font = '16px "Courier New", monospace';
+measureCtx.font = '16px "SF Mono", "Monaco", "Menlo", "Consolas", "Courier New", monospace';
 
 function expectInt(v: Value, name: string): number {
     if (v.kind !== 'int')
diff --git a/src/ui.ts b/src/ui.ts
index e513896..9be96e2 100644
--- a/src/ui.ts
+++ b/src/ui.ts
@@ -65,7 +65,7 @@ function renderUI(ui: UIValue, ctx: CanvasRenderingContext2D, x: number, y: numb
 
         case 'text':
             ctx.fillStyle = 'black';
-            ctx.font = '16px "Courier New", monospace';
+            ctx.font = '16px "SF Mono", "Monaco", "Menlo", "Consolas", "Courier New", monospace';
             ctx.fillText(ui.content, x + ui.x, y + ui.y);
             break;
 
@@ -119,7 +119,7 @@ function renderUI(ui: UIValue, ctx: CanvasRenderingContext2D, x: number, y: numb
 
         case 'text-input': {
             ctx.fillStyle = ui.value ? '#000000' : '#999999';
-            ctx.font = '16px monospace';
+            ctx.font = '16px "SF Mono", "Monaco", "Menlo", "Consolas", "Courier New", monospace';
             ctx.fillText(
                 ui.value || ui.placeholder,
                 x + ui.x + 8,