:root {
  --blue-deep: #266baa;
  --blue: #0ca3f4;
  --blue-text: #1f5b8e;
  --blue-soft: #edf6ff;
  --red: #cf4c4c;
  --text: #333;
  --muted: #666;
  --bg-gray: #f3f3f3;
  --border: #e5e5e5;
  --maxw: 1280px;
  --maxw-narrow: 1000px;
  --radius: 4px;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Hiragino Sans", "Noto Sans JP", "Yu Gothic", sans-serif;
  color: var(--text);
  line-height: 1.7;
  background: #fff;
}

img { max-width: 100%; height: auto; display: block; }

a { color: inherit; text-decoration: none; }

.container {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 0 24px;
}

/* Header */
.site-header {
  position: sticky;
  top: 0;
  background: #fff;
  z-index: 100;
  border-bottom: 1px solid var(--border);
}
.header-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
  height: 72px;
}
.logo img { width: 200px; height: auto; }
.site-nav {
  display: flex;
  gap: 12px;
  align-items: center;
  font-size: 14px;
  font-weight: 700;
}
.nav-btn {
  background: var(--blue-text);
  color: #fff;
  padding: 10px 16px;
  border-radius: var(--radius);
}

/* Hero */
.hero {
  position: relative;
  background: linear-gradient(135deg, var(--blue) 0%, var(--blue-deep) 100%);
  color: #fff;
  overflow: hidden;
  min-height: calc(100vh - 72px);
  display: flex;
  align-items: center;
}
.hero-inner {
  max-width: var(--maxw);
  width: 100%;
  margin: 0 auto;
  padding: 80px 24px 0;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 40px;
  align-items: center;
}
.hero-tag { font-size: 18px; margin: 0 0 8px; opacity: .95; }
.hero-title {
  font-family: "Times New Roman", "Hiragino Mincho ProN", serif;
  font-size: clamp(64px, 10vw, 130px);
  font-weight: 400;
  letter-spacing: 0.02em;
  line-height: 1;
  margin: 0;
}
.hero-sub { font-size: 18px; margin: 12px 0 24px; letter-spacing: 0.2em; }
.hero-lead { max-width: 480px; font-size: 14px; line-height: 1.9; margin: 0 0 32px; }
.hero-btn {
  display: inline-block;
  background: #fff;
  color: var(--blue-text);
  padding: 14px 40px;
  border-radius: 999px;
  font-weight: 700;
  font-size: 14px;
  transition: transform .2s;
}
.hero-btn:hover { transform: translateY(-2px); }
.hero-image img { width: 360px; max-width: 100%; height: auto; margin: 0 auto; }
.hero-divider {
  position: absolute;
  bottom: -1px;
  left: 0;
  width: 100%;
  height: 180px;
  display: block;
}

/* Hero animations */
@keyframes fadeLeft {
  from { opacity: 0; transform: translateX(-60px); }
  to   { opacity: 1; transform: translateX(0); }
}
@keyframes fadeRight {
  from { opacity: 0; transform: translateX(60px); }
  to   { opacity: 1; transform: translateX(0); }
}
.hero-tag,
.hero-title,
.hero-sub,
.hero-lead,
.hero-btn {
  opacity: 0;
  animation: fadeLeft .9s ease-out forwards;
}
.hero-tag   { animation-delay: 0.1s; }
.hero-title { animation-delay: 0.3s; }
.hero-sub   { animation-delay: 0.6s; }
.hero-lead  { animation-delay: 0.8s; }
.hero-btn   { animation-delay: 1.0s; }
.hero-image img {
  opacity: 0;
  animation: fadeRight 1.4s ease-out 1.0s forwards;
}

/* Section titles */
.section-title {
  font-size: 28px;
  color: var(--blue-text);
  text-align: center;
  font-weight: 500;
  letter-spacing: 0.08em;
  margin: 0 0 40px;
}
.section-lead {
  text-align: center;
  margin: -20px 0 40px;
  color: var(--muted);
}
.panel-title {
  font-size: 21px;
  font-weight: 700;
  border-bottom: 1px solid #eee;
  padding-bottom: 16px;
  margin: 0 0 32px;
  text-align: center;
}
.panel-title--left {
  text-align: left;
  padding-bottom: 4px;
  margin-bottom: 40px;
  border-bottom-color: #ddd;
}

/* Features */
.features { padding: 40px 0 80px; }
.features .container { background: var(--blue-soft); padding: 80px 48px; }
.features .section-title { font-size: 32px; }
.features-grid {
  list-style: none;
  padding: 0;
  margin: 0;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 40px 24px;
}
.features-grid li { text-align: center; }
.feature-num {
  display: block;
  font-family: "Times New Roman", serif;
  font-size: 50px;
  color: rgb(129, 137, 141);
  line-height: 1;
  margin-bottom: 12px;
}
.features-grid h3 {
  font-size: 23px;
  margin: 0 0 8px;
  letter-spacing: 0.08em;
  color: rgb(82, 91, 99);
}
.features-grid p {
  font-size: 14px;
  color: var(--muted);
  margin: 0;
}

/* Modes */
.modes { padding: 80px 0 60px; }
.modes .section-title { font-size: 32px; }
.modes .section-lead { font-size: 20px; }
.modes-grid {
  list-style: none;
  padding: 0;
  margin: 0 auto;
  max-width: var(--maxw-narrow);
  display: grid;
  grid-template-columns: repeat(6, 1fr);
  gap: 16px;
}
.modes-grid li { text-align: center; }
.modes-grid img { width: 130px; height: auto; margin: 0 auto 12px; }
.modes-grid h3 { font-size: 23px; margin: 0 0 4px; font-weight: 700; }
.modes-grid p { font-size: 14px; color: var(--muted); margin: 0; line-height: 1.6; }

/* Panel (basic modes) */
.panel { padding: 60px 0; }
.panel > .container:first-child { background: var(--bg-gray); padding: 80px 48px; }
.panel-highlight {
  font-weight: 700;
  font-size: 18px;
  background: #fff566;
  padding: 0 4px;
  line-height: 1.2;
  box-decoration-break: clone;
  -webkit-box-decoration-break: clone;
  display: block;
  width: fit-content;
  margin: 0 auto 24px;
  text-align: center;
}
.panel-list {
  list-style: none;
  padding: 0;
  text-align: center;
  font-size: 16px;
  margin: 0 0 40px;
}
.panel-list li { margin: 8px 0; }
.panel-figure { background: #fff; margin: 0; padding: 48px; }

.season-grid {
  list-style: none;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 40px;
  margin: 0;
  padding: 80px 0;
}
.season-grid li { text-align: center; }
.season-grid img { width: 100%; margin: 0 0 12px; }
.season-label {
  display: block;
  background: #81898d;
  color: #fff;
  padding: 0 16px;
  margin: 0 0 8px;
  font-size: 18px;
}
.season-sub { font-size: 18px; color: #000; margin: 0; }

/* Principle */
.principle { padding: 60px 0; }
.principle > .container { background: var(--bg-gray); padding: 80px 48px; }
.principle .section-lead { font-size: 16px; color: #000; }
.principle-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
}
.principle-card {
  background: #fff;
  border-radius: var(--radius);
  padding: 32px;
}
.principle-card img { margin: 24px auto; }
.p-title {
  text-align: center;
  font-size: 21px;
  padding-bottom: 16px;
  border-bottom: 1px solid #ddd;
  margin: 0 0 24px;
}
.p-title--blue { color: rgb(0, 92, 167); }
.p-title--red { color: var(--red); }
.p-state {
  padding: 20px;
  text-align: center;
  margin-bottom: 24px;
  border-radius: var(--radius);
  font-size: 20px;
}
.p-state--blue { background: #f5fbff; }
.p-state--red { background: #fffcf6; }
.p-state p { margin: 4px 0; }
.p-state--blue p:last-child { color: rgb(0, 92, 167); }
.p-state--red p:last-child { color: var(--red); }
.arrow-down { color: #888; font-size: 12px; }
.mark-blue { background: rgb(0, 92, 167); color: #fff; border-radius: 2px; }
.mark-red { background: var(--red); color: #fff; border-radius: 2px; }

/* Filter */
.filter { padding: 80px 0; }
.filter-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 48px;
  align-items: center;
}
.filter-text p { font-size: 16px; line-height: 1.9; color: #333; }
.filter-text p.filter-note { font-size: 13px; margin-top: 24px; }
.filter-figure { margin: 0; text-align: center; }
.filter-figure figcaption {
  font-size: 13px;
  color: #333;
  text-align: left;
  margin-top: 12px;
}

/* System */
.system { padding: 60px 0; background: var(--blue-soft); }
.system figure { margin: 0; text-align: center; }
.system figure img { max-width: 1024px; width: 100%; margin: 0 auto; }
.system-note {
  text-align: center;
  font-size: 20px;
  color: #000;
  margin: 32px 0 0;
}

/* Appearance */
.appearance { padding: 60px 0; }
.appearance-box {
  border: 5px solid #f7f7f7;
  padding: 28px;
}
.appearance-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
  margin: 0 0 60px;
}
.appearance-grid figure { margin: 0; }
.spec-figure { margin: 0; text-align: center; }
.spec-figure img { width: 100%; max-width: 700px; height: auto; margin: 0 auto; }

/* Video */
.video { padding: 40px 0 80px; }
.video-wrap {
  position: relative;
  max-width: var(--maxw-narrow);
  margin: 0 auto;
  aspect-ratio: 16 / 9;
}
.video-wrap iframe {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  border: 0;
}

/* Footer */
.site-footer { padding: 60px 0 0; text-align: center; }
.footer-logo { height: 42px; width: auto; margin: 0 auto 32px; }
.footer-link {
  font-size: 13px;
  margin: 0;
  padding: 24px 0;
  color: var(--muted);
  border-top: 1px solid var(--border);
}
.footer-link a:hover { color: var(--blue-text); }
.footer-copy {
  font-size: 13px;
  color: #fff;
  background: #04103d;
  margin: 0;
  padding: 20px 0;
}

/* Back to top */
.back-to-top {
  position: fixed;
  right: 24px;
  bottom: 24px;
  width: 48px;
  height: 48px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--blue-deep);
  color: #fff;
  border-radius: 50%;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
  opacity: 0;
  visibility: hidden;
  transform: translateY(10px);
  transition: opacity 0.3s, transform 0.3s, visibility 0.3s;
  z-index: 100;
}
.back-to-top.is-visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}
.back-to-top:hover { background: var(--blue-text); }

/* Responsive */
@media (max-width: 900px) {
  .hero { min-height: 0; display: block; }
  .hero-inner {
    grid-template-columns: 1fr;
    text-align: center;
    padding: 24px 24px 60px;
    gap: 32px;
  }
  .hero-text {
    min-height: calc(100vh - 60px - 48px);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
  }
  .hero-lead { max-width: 100%; }
  .hero-image { padding-top: 20px; text-align: center; }
  .hero-image img { width: auto; max-width: 80%; max-height: 400px; object-fit: contain; }
  .hero-divider { display: none; }

  .header-inner { height: 60px; }
  .logo img { width: 140px; }
  .site-nav { gap: 4px; font-size: 11px; flex-shrink: 0; }
  .nav-btn { padding: 6px 8px; white-space: nowrap; }

  .features-grid { grid-template-columns: repeat(2, 1fr); gap: 32px 16px; }
  .modes-grid { grid-template-columns: repeat(3, 1fr); }
  .season-grid,
  .principle-grid,
  .appearance-grid,
  .filter-grid { grid-template-columns: 1fr; }

  .features .container,
  .panel > .container:first-child,
  .principle > .container { padding: 48px 24px; }
  .panel-figure,
  .principle-card { padding: 24px; }
  .appearance-box { padding: 20px; border-width: 3px; }
  .filter-grid,
  .principle-grid { gap: 32px; }
  .season-grid { padding: 48px 0; }

  .section-title,
  .features .section-title { font-size: 26px; }
}

@media (max-width: 500px) {
  .hero-title { font-size: 64px; }
  .modes-grid { grid-template-columns: repeat(2, 1fr); }
  .features-grid { grid-template-columns: 1fr; }
  .features .container,
  .panel > .container:first-child,
  .principle > .container { padding: 40px 20px; }
  .panel-figure,
  .appearance-box { padding: 16px; }
  .container { padding: 0 16px; }
  .logo img { width: 110px; }
  .site-nav { font-size: 10px; gap: 3px; }
  .nav-btn { padding: 6px 6px; }
  .back-to-top { right: 16px; bottom: 16px; width: 42px; height: 42px; }
}