When setting up the full screen, you need to set the LGlobal.stageScalefirst.

Next, call the LSystem.screen(LStage.FULL_SCREEN);

※On mobile web page, must add this meta tag to the head tag.

<meta name="viewport" content="width=device-width,initial-scale=1.0,minimum-scale=1.0,maximum-scale=1.0,user-scalable=no">