:root {
  --ink: #1e293b;
  --gray: #64748b;
  --line: #e2e8f0;
  --bg: #f8fafc;
  --accent: #2563eb;
  --maxw: 920px;
}

* { margin: 0; padding: 0; box-sizing: border-box; }

body {
  font-family: "Noto Sans JP", sans-serif;
  color: var(--ink);
  background: var(--bg);
  line-height: 1.85;
  font-size: 15px;
}

img, video { max-width: 100%; display: block; }

.demo-header {
  background: #fff;
  border-bottom: 1px solid var(--line);
  padding: 14px 20px;
  position: sticky;
  top: 0;
  z-index: 20;
}

.demo-header-inner {
  max-width: var(--maxw);
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
}

.demo-tag {
  font-size: 11px;
  font-weight: 700;
  letter-spacing: .08em;
  color: var(--accent);
}

.demo-header h1 {
  font-size: 18px;
  font-weight: 800;
}

.demo-header a {
  font-size: 13px;
  font-weight: 700;
  color: var(--accent);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.demo-main {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 32px 20px 72px;
}

.demo-intro {
  margin-bottom: 20px;
}

.demo-intro h2 {
  font-size: clamp(22px, 4vw, 28px);
  font-weight: 800;
  margin-bottom: 10px;
}

.demo-intro p {
  color: var(--gray);
  font-size: 14px;
}

/* ===== Hero video ===== */
.hero-video {
  position: relative;
  width: 100%;
  height: min(78vh, 760px);
  min-height: 420px;
  overflow: hidden;
  background: #0f172a;
}

.hero-video__media {
  position: absolute;
  inset: 0;
}

.hero-video__media video {
  width: 100%;
  height: 100%;
  object-fit: cover;
  vertical-align: bottom;
}

.hero-video__overlay {
  position: absolute;
  inset: 0;
  background:
    linear-gradient(180deg, rgba(15, 23, 42, .28) 0%, rgba(15, 23, 42, .08) 42%, rgba(15, 23, 42, .55) 100%);
  pointer-events: none;
}

.hero-video__overlay::after {
  content: "";
  position: absolute;
  inset: 0;
  opacity: .08;
  background-image: radial-gradient(#fff 0.6px, transparent 0.6px);
  background-size: 3px 3px;
}

.hero-video__content {
  position: absolute;
  left: clamp(20px, 8vw, 96px);
  bottom: clamp(72px, 16%, 120px);
  z-index: 2;
  color: #fff;
  max-width: min(560px, 78vw);
}

.hero-video__catch {
  font-size: clamp(24px, 4.8vw, 40px);
  font-weight: 800;
  line-height: 1.55;
  letter-spacing: .14em;
  text-shadow: 0 2px 24px rgba(0, 0, 0, .35);
}

.hero-video__lead {
  margin-top: 14px;
  font-size: clamp(13px, 2vw, 15px);
  line-height: 1.9;
  color: rgba(255, 255, 255, .88);
  letter-spacing: .06em;
}

.hero-video__scroll {
  position: absolute;
  left: clamp(16px, 4vw, 56px);
  bottom: clamp(24px, 6%, 48px);
  z-index: 2;
  color: #fff;
  font-size: 11px;
  font-weight: 700;
  letter-spacing: .28em;
  writing-mode: vertical-rl;
  text-orientation: mixed;
}

.hero-video__scroll::after {
  content: "";
  display: block;
  width: 1px;
  height: 56px;
  margin-top: 10px;
  margin-inline: auto;
  background: rgba(255, 255, 255, .75);
  animation: hero-scroll-line 1.8s ease-in-out infinite;
}

@keyframes hero-scroll-line {
  0% { transform: scaleY(0); transform-origin: top; opacity: 0; }
  40% { opacity: 1; }
  100% { transform: scaleY(1); transform-origin: top; opacity: .35; }
}

.demo-note {
  margin-top: 28px;
  text-align: center;
  font-size: 15px;
  font-weight: 700;
  color: var(--accent);
}

@media (max-width: 680px) {
  .hero-video {
    min-height: 360px;
    height: 68vh;
  }

  .hero-video__catch {
    letter-spacing: .08em;
  }

  .hero-video__lead {
    display: none;
  }
}

@media (prefers-reduced-motion: reduce) {
  .hero-video__media video {
    display: none;
  }

  .hero-video {
    background:
      linear-gradient(135deg, #334155 0%, #0f172a 100%);
  }

  .hero-video__scroll::after {
    animation: none;
    opacity: .75;
    transform: none;
  }
}