:root {
  --ink: #163047;
  --navy: #102638;
  --blue: #1278b8;
  --sky: #eaf5fb;
  --orange: #ec641f;
  --yellow: #f6c900;
  --paper: #fffdf8;
  --line: #d8e0e5;
  --muted: #546571;
  --shadow: 0 18px 48px rgba(22, 48, 71, .09);
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  color: var(--ink);
  background: #f5f8fa;
  font-family: "Yu Gothic", "Hiragino Kaku Gothic ProN", system-ui, sans-serif;
  line-height: 1.8;
}
img { display: block; max-width: 100%; }
a { color: inherit; }

.site-header {
  position: sticky;
  z-index: 50;
  top: 0;
  display: flex;
  min-height: 72px;
  align-items: center;
  gap: 32px;
  padding: 10px max(24px, calc((100% - 1240px) / 2));
  border-bottom: 4px solid var(--yellow);
  background: rgba(16, 38, 56, .98);
  color: #fff;
}
.brand { display: flex; align-items: center; gap: 13px; text-decoration: none; white-space: nowrap; }
.brand strong { padding: 7px 13px; border-radius: 6px; background: var(--yellow); color: var(--navy); font-style: italic; }
.brand span { font-weight: 800; }
#page-nav { display: flex; gap: 22px; margin-left: auto; }
#page-nav a { color: #fff; font-size: 14px; font-weight: 800; text-decoration: none; }
#page-nav a:hover { color: var(--yellow); }
.menu-button { display: none; margin-left: auto; padding: 9px 14px; border: 1px solid #607180; border-radius: 6px; background: transparent; color: #fff; }

.hero {
  display: block;
  background: linear-gradient(135deg, #f4f9fc 0%, #dcecf5 100%);
}
.hero-copy { display: flex; flex-direction: column; align-items: center; justify-content: center; padding: 52px 24px 48px; text-align: center; }
.kicker, .section-label { margin: 0 0 14px; color: var(--orange); font-size: 14px; font-weight: 900; letter-spacing: .08em; }
.hero h1 { margin: 0; color: var(--navy); font-family: "Yu Mincho", "Hiragino Mincho ProN", serif; font-size: clamp(40px, 4vw, 60px); line-height: 1.35; letter-spacing: -.035em; }
.hero h1 span { display: block; white-space: nowrap; }
.hero-lead { margin: 24px 0 0; color: #456174; font-size: clamp(14px, 1.2vw, 17px); font-weight: 800; letter-spacing: .06em; }
.hero-visual { position: relative; margin: 0; overflow: hidden; background: #cfe7f5; }
.hero-visual img { display: block; width: 100%; height: auto; object-fit: contain; filter: brightness(.92) saturate(1.05) contrast(1.02); }
.hero-visual figcaption { position: absolute; right: 18px; bottom: 16px; padding: 7px 10px; border-radius: 4px; background: rgba(255,255,255,.88); color: #304655; font-size: 12px; font-weight: 700; }

.intro, .case-section, .cta { width: min(1240px, calc(100% - 48px)); margin-inline: auto; }
.intro { padding: 80px 0 30px; text-align: center; }
.intro p { margin: 0; color: var(--blue); font-weight: 900; }
.intro h2 { margin: 10px 0 0; font-family: "Yu Mincho", "Hiragino Mincho ProN", serif; font-size: clamp(28px, 3.6vw, 48px); line-height: 1.45; }

.case-section { padding: 84px 0; border-bottom: 1px solid var(--line); scroll-margin-top: 78px; }
.section-heading { max-width: 820px; margin-bottom: 42px; }
.section-heading h2 { margin: 0; font-family: "Yu Mincho", "Hiragino Mincho ProN", serif; font-size: clamp(32px, 4vw, 54px); line-height: 1.4; }
.section-heading > p:last-child { margin: 18px 0 0; color: var(--muted); font-size: 17px; font-weight: 700; }

.timeline { position: relative; display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 18px; }
.photo-card { position: relative; z-index: 1; overflow: hidden; border: 1px solid var(--line); border-radius: 10px; background: var(--paper); box-shadow: var(--shadow); }
.photo-stage { position: relative; aspect-ratio: 4 / 3; overflow: hidden; background: #dce7ed; }
.photo-button { display: block; width: 100%; height: 100%; margin: 0; padding: 0; border: 0; background: transparent; cursor: zoom-in; }
.photo-button:focus-visible { outline: 4px solid var(--yellow); outline-offset: -4px; }
.photo-stage img { width: 100%; height: 100%; object-fit: cover; }
.photo-stage.photo-contain img { object-fit: contain; }
.step-number { position: absolute; z-index: 2; top: 14px; left: 14px; display: grid; width: 42px; height: 42px; place-items: center; border-radius: 50%; background: var(--yellow); color: var(--navy); font-weight: 900; box-shadow: 0 4px 15px rgba(16,38,56,.2); }
.photo-copy { padding: 21px 20px 24px; }
.photo-copy h4 { margin: 0; font-size: 18px; line-height: 1.45; }
.photo-copy p { margin: 9px 0 0; color: var(--muted); font-size: 14px; }

.split-section, .ventilation-section { background: transparent; }
.method-block { display: grid; grid-template-columns: minmax(260px, .58fr) minmax(0, 1.42fr); gap: 36px; align-items: start; padding: 34px; border-radius: 12px; background: #fff; box-shadow: var(--shadow); }
.method-copy h2 { margin: 0 0 12px; font-family: "Yu Mincho", "Hiragino Mincho ProN", serif; font-size: clamp(26px, 3vw, 39px); line-height: 1.4; }
.method-copy p { margin: 0; color: var(--muted); font-weight: 700; }
.photo-pair { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 18px; }
.compact-photo .photo-stage { aspect-ratio: 16 / 10; }

.mugi-section { width: 100%; max-width: none; padding-inline: max(24px, calc((100% - 1240px) / 2)); background: #e9f4fa; }
.mugi-section > .section-heading { max-width: 1240px; margin-inline: auto; }
.method-stack { display: grid; width: min(1240px, 100%); margin: 0 auto; gap: 30px; }
.extra-section { margin-top: 70px; padding: 72px max(30px, 5vw); border: 2px solid #e1c661; border-radius: 14px; background: #fffaf0; }

.cta { display: flex; align-items: center; justify-content: space-between; gap: 30px; margin-block: 90px; padding: 46px; border-radius: 12px; background: var(--navy); color: #fff; }
.cta p { margin: 0 0 6px; color: #b9d7e8; font-weight: 800; }
.cta h2 { margin: 0; font-family: "Yu Mincho", "Hiragino Mincho ProN", serif; font-size: clamp(26px, 3vw, 42px); }
.cta a { flex: none; padding: 15px 24px; border-radius: 6px; background: var(--yellow); color: var(--navy); font-weight: 900; text-decoration: none; }
footer { padding: 38px; border-top: 5px solid var(--yellow); background: #101820; color: #c5ced5; text-align: center; }

.lightbox { position: fixed; width: min(1180px, 94vw); max-width: none; padding: 0; border: 0; border-radius: 16px; background: #090c10; box-shadow: 0 24px 90px rgba(0,0,0,.5); }
.lightbox::backdrop { background: rgba(0,0,0,.86); }
.lightbox img { display: block; max-width: 94vw; max-height: 88vh; margin: auto; object-fit: contain; }
.lightbox-close { position: absolute; z-index: 2; top: 8px; right: 10px; display: grid; width: 44px; height: 44px; place-items: center; padding: 0; border: 0; border-radius: 50%; background: rgba(255,255,255,.92); color: var(--navy); font-size: 27px; cursor: pointer; }
.lightbox-close:focus-visible { outline: 4px solid var(--yellow); outline-offset: 2px; }

@media (max-width: 980px) {
  .method-block { grid-template-columns: 1fr; }
}

@media (max-width: 900px) {
  .hero h1 { font-size: 44px; }
}

@media (max-width: 720px) {
  .site-header { min-height: 64px; padding-inline: 15px; }
  .brand span { font-size: 14px; }
  .menu-button { display: block; }
  #page-nav { position: absolute; top: 64px; right: 12px; display: none; width: 210px; padding: 14px; border-radius: 6px; background: var(--navy); box-shadow: var(--shadow); }
  #page-nav.is-open { display: grid; }
  #page-nav a { padding: 7px 8px; }
  .hero-copy { padding: 40px 24px 36px; }
  .hero h1 { font-size: 30px; }
  .hero-visual figcaption { right: 10px; bottom: 10px; font-size: 10px; }
  .intro, .case-section, .cta { width: min(100% - 28px, 1240px); }
  .intro { padding-top: 56px; }
  .case-section { padding: 60px 0; }
  .timeline { grid-template-columns: 1fr; gap: 22px; }
  .timeline .photo-card { display: grid; grid-template-columns: 43% 57%; }
  .timeline .photo-stage { aspect-ratio: 1 / 1; }
  .photo-pair { grid-template-columns: 1fr; }
  .method-block { padding: 20px; }
  .mugi-section { width: 100%; padding-inline: 14px; }
  .extra-section { padding-inline: 20px; }
  .cta { align-items: stretch; flex-direction: column; padding: 30px 24px; }
  .cta a { text-align: center; }
}

/* 2026-09-02: 暑さ対策向け 70% / 25% / 5% 配色補正 */
:root {
  --ink: #0f172a;
  --navy: #475569;
  --blue: #0284c7;
  --sky: #e0f2fe;
  --orange: #ea580c;
  --yellow: #f79428;
  --paper: #ffffff;
  --line: #cbd5e1;
  --muted: #475569;
  --shadow: 0 18px 48px rgba(15, 23, 42, 0.1);
}
body { background: #f8fafc; color: var(--ink); }
.site-header { background: rgba(71, 85, 105, 0.98); }
.hero { background: linear-gradient(135deg, #f8fafc 0%, var(--sky) 100%); }
.mugi-section { background: #eff8fd; }
.cta { background: var(--navy); }
.cta a,
.brand strong,
.step-number { background: var(--yellow); color: var(--ink); }
footer { border-top-color: var(--yellow); background: var(--ink); }