/**
 * PRESENS - スクロールアニメーション
 * Intersection Observer と連携。prefers-reduced-motion 対応。
 */

/* ===== Fade In ===== */
.fade {
	opacity: 0;
	transition: opacity 0.8s cubic-bezier(0.165, 0.84, 0.44, 1),
	            transform 0.8s cubic-bezier(0.165, 0.84, 0.44, 1);
}

.fade-up {
	opacity: 0;
	transform: translateY(40px);
	transition: opacity 0.8s cubic-bezier(0.165, 0.84, 0.44, 1),
	            transform 0.8s cubic-bezier(0.165, 0.84, 0.44, 1);
}

.fade-in {
	opacity: 1;
	transform: translateY(0);
}

/* ===== Hero Logo Animation ===== */
.presens-hero__logo {
	opacity: 0;
	transform: scale(0.95);
	transition: opacity 1.2s ease-out, transform 1.2s ease-out;
}

.presens-hero__logo.is-visible {
	opacity: 1;
	transform: scale(1);
}

.presens-hero__tagline {
	opacity: 0;
	transform: translateY(20px);
	transition: opacity 0.8s ease-out 0.6s, transform 0.8s ease-out 0.6s;
}

.presens-hero__tagline.is-visible {
	opacity: 1;
	transform: translateY(0);
}

/* ===== Stagger Children ===== */
.stagger-children > * {
	opacity: 0;
	transform: translateY(30px);
	transition: opacity 0.6s cubic-bezier(0.165, 0.84, 0.44, 1),
	            transform 0.6s cubic-bezier(0.165, 0.84, 0.44, 1);
}

.stagger-children.fade-in > *:nth-child(1) { transition-delay: 0s; }
.stagger-children.fade-in > *:nth-child(2) { transition-delay: 0.1s; }
.stagger-children.fade-in > *:nth-child(3) { transition-delay: 0.2s; }
.stagger-children.fade-in > *:nth-child(4) { transition-delay: 0.3s; }
.stagger-children.fade-in > *:nth-child(5) { transition-delay: 0.4s; }

.stagger-children.fade-in > * {
	opacity: 1;
	transform: translateY(0);
}

/* ===== Origin Story Arrow ===== */
.origin-arrow {
	opacity: 0;
	transform: translateY(-10px);
	transition: opacity 0.5s ease 0.3s, transform 0.5s ease 0.3s;
}

.origin-arrow.fade-in {
	opacity: 1;
	transform: translateY(0);
}

/* ===== Flow Diagram ===== */
.flow-step {
	opacity: 0;
	transform: translateX(-20px);
	transition: opacity 0.6s ease, transform 0.6s ease;
}

.flow-step.fade-in {
	opacity: 1;
	transform: translateX(0);
}

.flow-step:nth-child(2) { transition-delay: 0.15s; }
.flow-step:nth-child(3) { transition-delay: 0.3s; }
.flow-step:nth-child(4) { transition-delay: 0.45s; }
.flow-step:nth-child(5) { transition-delay: 0.6s; }

/* ===== Reduced Motion ===== */
@media (prefers-reduced-motion: reduce) {
	.fade,
	.fade-up,
	.presens-hero__logo,
	.presens-hero__tagline,
	.stagger-children > *,
	.origin-arrow,
	.flow-step {
		opacity: 1;
		transform: none;
		transition: none;
	}
}