jsでブレイクポイントで切り替え

// breakPoint
//=====================================================
$windowWidth = window.innerWidth;
$breakPointA = 768;
$breakPointB = 1100;
isSP = ($windowWidth < $breakPointA);
isTB = ($windowWidth <= $breakPointB) && ($windowWidth > $breakPointA);
isPC = ($windowWidth > $breakPointB);
isSPTB = ($windowWidth < $breakPointB);

//汎用 スムーズスクロール
const smoothScrollTrigger = document.querySelectorAll('a[href^="#"]');
for (let i = 0; i < smoothScrollTrigger.length; i++) {
	smoothScrollTrigger[i].addEventListener('click', (e) => {
		e.preventDefault();
		let href = smoothScrollTrigger[i].getAttribute('href');
		let targetElement = document.getElementById(href.replace('#', ''));
		const rect = targetElement.getBoundingClientRect().top;
		const offset = window.pageYOffset;
		const gapSPTB = 65;
		const gapPC = 0;
		const targetSPTB = rect + offset - gapSPTB;
		const targetPC = rect + offset - gapPC;
		if(isSPTB) {
			window.scrollTo({
				top: targetSPTB,
				behavior: 'smooth',
			});
		}
		if(isPC) {
			window.scrollTo({
				top: targetPC,
				behavior: 'smooth',
			});
		}
	});
}