:root {
  --bg: #f6f8fb;
  --surface: #ffffff;
  --text-main: #1b2d3f;
  --text-sub: #4f6379;
  --primary: #2f68d9;
  --line: #dbe4ef;
}

* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  min-height: 100%;
  background: var(--bg);
  color: var(--text-main);
  font-family: "Noto Sans JP", sans-serif;
}

img {
  max-width: 100%;
}

.site-shell {
  width: min(1080px, calc(100% - 40px));
  margin: 24px auto 40px;
}

.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 28px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
  color: inherit;
  font-size: 1.2rem;
  font-weight: 700;
}

.brand img {
  width: 48px;
  height: 48px;
  border-radius: 12px;
}

.lang-switch {
  display: inline-flex;
  align-items: center;
  gap: 2px;
  padding: 3px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: #fff;
}

.lang-button {
  border: 0;
  background: transparent;
  color: #71849a;
  font-size: 0.88rem;
  font-weight: 700;
  border-radius: 999px;
  padding: 6px 12px;
  cursor: pointer;
}

.lang-button.is-active {
  color: #fff;
  background: var(--primary);
}

.hero {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  gap: 36px;
  padding: 40px 40px 0;
  border-radius: 28px;
  border: 1px solid var(--line);
  background: var(--surface);
  overflow: hidden;
}

.hero-copy {
  display: flex;
  flex-direction: column;
  align-items: center;
  max-width: 800px;
  width: 100%;
}

.hero-eyebrow {
  margin: 0 0 10px;
  color: #34557c;
  font-size: 0.95rem;
  font-weight: 700;
}

.hero-title {
  margin: 0;
  line-height: 1.2;
  font-size: clamp(1.2rem, 4vw, 2.4rem);
  white-space: nowrap;
}

.hero-description {
  margin: 16px 0 20px;
  line-height: 1.85;
  color: var(--text-sub);
}

.store-link {
  display: inline-block;
}

.store-badge {
  width: 185px;
  height: auto;
}

.hero-visual {
  width: 100%;
  max-width: 800px;
  margin-top: auto;
}

.hero-visual img {
  display: block;
  border-radius: 16px 16px 0 0;
  width: 100%;
  height: auto;
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.08);
}

.demo-video,
.screenshots,
.notes,
.final-cta {
  margin-top: 34px;
  padding: 30px;
  border-radius: 28px;
  border: 1px solid var(--line);
  background: var(--surface);
}

.demo-video h2,
.screenshots h2,
.notes h2,
.final-cta h2 {
  margin: 0;
  font-size: clamp(1.4rem, 2vw, 1.95rem);
}

.video-container {
  margin-top: 18px;
  position: relative;
  width: 100%;
  padding-bottom: 56.25%; /* 16:9 Aspect Ratio */
  border-radius: 16px;
  overflow: hidden;
  background: #000;
}

.video-container iframe {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
}

.carousel {
  margin-top: 18px;
  display: grid;
  grid-template-columns: auto minmax(0, 1fr) auto;
  align-items: center;
  gap: 14px;
}

.carousel-button {
  width: 40px;
  height: 40px;
  border: 1px solid var(--line);
  background: #fff;
  border-radius: 50%;
  font-size: 1.65rem;
  line-height: 1;
  color: #435d78;
  cursor: pointer;
}

.slide-window {
  overflow: hidden;
}

.slide-track {
  display: flex;
  gap: 12px;
  transition: transform 260ms ease;
  will-change: transform;
}

.slide-card {
  margin: 0;
  flex: 0 0 calc((100% - 24px) / 3);
  width: calc((100% - 24px) / 3);
  border: 1px solid var(--line);
  border-radius: 14px;
  background: #fbfdff;
  overflow: hidden;
}

.slide-card img {
  display: block;
  width: 100%;
  aspect-ratio: 9 / 16;
  object-fit: cover;
  background: #f3f7fc;
}

.slide-caption {
  margin: 0;
  padding: 10px 10px 12px;
  font-size: 0.87rem;
  line-height: 1.5;
  color: var(--text-sub);
}

.notes-subtitle {
  margin: 10px 0 0;
  color: var(--text-sub);
}

.notes-grid {
  margin-top: 18px;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
}

.note-card {
  border: 1px solid var(--line);
  border-radius: 16px;
  padding: 18px;
  background: #fcfdff;
}

.note-card h3 {
  margin: 0;
  font-size: 1.08rem;
}

.note-card ul {
  margin: 10px 0 0;
  padding-left: 18px;
  line-height: 1.8;
  color: var(--text-sub);
}

.final-cta {
  text-align: center;
  background: linear-gradient(180deg, #ffffff, #f9fbff);
}

.final-cta p {
  margin: 12px 0 18px;
  color: var(--text-sub);
}

.site-footer {
  margin-top: 20px;
  border-top: 1px solid var(--line);
  padding-top: 16px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 14px;
  color: #6f8398;
  font-size: 0.92rem;
}

.site-footer a {
  color: #2f68d9;
  text-decoration: none;
}

@media (max-width: 920px) {
  .site-shell {
    width: min(100%, calc(100% - 24px));
    margin: 12px auto 24px;
  }

  .hero,
  .demo-video,
  .screenshots,
  .notes,
  .final-cta {
    padding: 20px;
    border-radius: 22px;
    margin-top: 20px;
  }

  .hero {
    padding: 30px 20px 0;
    gap: 24px;
  }

  .slide-card {
    flex-basis: calc((100% - 12px) / 2);
    width: calc((100% - 12px) / 2);
  }

  .notes-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 640px) {
  .site-header,
  .site-footer {
    flex-direction: column;
    align-items: flex-start;
    gap: 10px;
  }

  .carousel {
    grid-template-columns: 1fr;
  }

  .carousel-button {
    justify-self: center;
  }

  .slide-card {
    flex-basis: 100%;
    width: 100%;
  }
}