iphone x対策
viewport-fit=coverを設定。
<meta name="viewport" content="width=device-width,initial-scale=1.0, viewport-fit=cover">
↑画面切れ回避
padding: constant(safe-area-inset-top) constant(safe-area-inset-right) constant(safe-area-inset-bottom) constant(safe-area-inset-left);
↑コンテンツ切れ回避