:root {
  --navy: #081c3a;
  --navy-2: #0b2d63;
  --blue: #1457d9;
  --blue-dark: #0e3c9d;
  --cyan: #35c4d8;
  --orange: #ff704d;
  --sky: #eaf2ff;
  --mist: #f3f6fa;
  --white: #fff;
  --text: #263b55;
  --muted: #697b91;
  --line: #dce4ef;
  --max: 1240px;
  --radius: 22px;
  --shadow: 0 24px 70px rgba(8, 28, 58, .14);
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; color: var(--text); background: var(--white); font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif; font-size: 16px; line-height: 1.66; -webkit-font-smoothing: antialiased; }
body.menu-open { overflow: hidden; }
img { display: block; width: 100%; }
a { color: inherit; text-decoration: none; }
button { font: inherit; color: inherit; }
.wrap { width: min(calc(100% - 48px), var(--max)); margin-inline: auto; }
.skip { position: fixed; top: -70px; left: 20px; z-index: 1000; padding: 10px 15px; color: var(--white); background: var(--blue); }
.skip:focus { top: 20px; }

.topline { color: #c9d7ea; background: var(--navy); }
.topline .wrap { min-height: 36px; display: flex; align-items: center; justify-content: space-between; gap: 24px; font-size: .76rem; }
.topline-links { display: flex; align-items: center; gap: 20px; }
.topline a:hover { color: var(--white); }
.header { position: sticky; top: 0; z-index: 100; background: rgba(255,255,255,.96); border-bottom: 1px solid var(--line); backdrop-filter: blur(16px); }
.header-row { min-height: 102px; display: flex; align-items: center; justify-content: space-between; gap: 24px; }
.logo { display: inline-flex; align-items: center; gap: 0; flex: 0 0 auto; }
.logo img { width: 132px; height: 88px; object-fit: contain; }
.logo-text { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip: rect(0, 0, 0, 0); white-space: nowrap; border: 0; }
.logo-text strong { color: var(--navy); font-size: .98rem; letter-spacing: .075em; }
.logo-text small { margin-top: 7px; color: var(--blue); font-size: .65rem; font-weight: 800; letter-spacing: .18em; }
.main-nav { display: flex; align-items: center; gap: 2px; }
.main-nav > a { padding: 11px 12px; color: #415876; font-size: .84rem; font-weight: 730; }
.main-nav > a:hover, .main-nav > a[aria-current="page"] { color: var(--blue); }
.main-nav .nav-cta { margin-left: 10px; padding: 12px 17px; color: var(--white); background: var(--blue); border-radius: 999px; }
.main-nav .nav-cta:hover { color: var(--white); background: var(--blue-dark); }
.menu-button { display: none; width: 46px; height: 46px; padding: 0; border: 1px solid var(--line); border-radius: 50%; background: var(--white); cursor: pointer; }
.menu-button span, .menu-button::before, .menu-button::after { content: ""; display: block; width: 20px; height: 2px; margin: 5px auto; background: var(--navy); transition: .2s ease; }
.menu-button.active span { opacity: 0; }
.menu-button.active::before { transform: translateY(7px) rotate(45deg); }
.menu-button.active::after { transform: translateY(-7px) rotate(-45deg); }

h1, h2, h3, p { margin-top: 0; }
h1, h2, h3 { color: var(--navy); font-family: Georgia, "Times New Roman", serif; font-weight: 600; line-height: 1.05; letter-spacing: -.035em; }
h1 { margin-bottom: 24px; font-size: clamp(3.05rem, 7.1vw, 6.5rem); }
h2 { margin-bottom: 20px; font-size: clamp(2.25rem, 4.7vw, 4.35rem); }
h3 { margin-bottom: 13px; font-size: 1.48rem; }
.eyebrow { margin: 0 0 17px; color: var(--blue); font-size: .75rem; font-weight: 850; letter-spacing: .16em; text-transform: uppercase; }
.lead { color: var(--muted); font-size: clamp(1.03rem, 1.45vw, 1.18rem); }
.section { padding-block: 112px; }
.section-mist { background: var(--mist); }
.section-sky { background: var(--sky); }
.section-navy { color: var(--white); background: var(--navy); }
.section-navy h2, .section-navy h3 { color: var(--white); }
.section-navy .eyebrow { color: var(--cyan); }
.section-navy .lead, .section-navy p { color: #afc0d6; }
.section-head { display: grid; grid-template-columns: 1.08fr .92fr; align-items: end; gap: 80px; margin-bottom: 50px; }
.section-head > p { max-width: 560px; margin-bottom: 5px; }
.btn { display: inline-flex; min-height: 50px; align-items: center; justify-content: center; gap: 10px; padding: 0 22px; border: 1px solid var(--blue); border-radius: 999px; color: var(--white); background: var(--blue); font-size: .86rem; font-weight: 820; transition: transform .2s ease, background .2s ease; }
.btn:hover { transform: translateY(-2px); background: var(--blue-dark); }
.btn-white { color: var(--navy); background: var(--white); border-color: var(--white); }
.btn-white:hover { color: var(--white); background: var(--navy); border-color: var(--navy); }
.btn-outline { color: var(--white); background: transparent; border-color: rgba(255,255,255,.55); }
.btn-outline:hover { background: rgba(255,255,255,.12); }
.link { display: inline-flex; align-items: center; gap: 9px; color: var(--blue); font-size: .86rem; font-weight: 820; }
.link::after { content: "→"; transition: transform .2s ease; }
.link:hover::after { transform: translateX(4px); }

.hero { position: relative; min-height: 690px; display: flex; align-items: center; overflow: hidden; color: var(--white); background: var(--navy); }
.hero-bg { position: absolute; inset: 0; width: 100%; height: 100%; object-fit: contain; object-position: center; background: var(--navy); }
.hero::after { content: ""; position: absolute; inset: 0; background: linear-gradient(90deg, rgba(8,28,58,.94) 0%, rgba(8,28,58,.78) 44%, rgba(8,28,58,.18) 76%, rgba(8,28,58,.12) 100%); }
.hero-content { position: relative; z-index: 2; max-width: 790px; padding: 98px 0 170px; }
.hero .eyebrow { color: #82e7f2; }
.hero h1 { max-width: 760px; color: var(--white); }
.hero .lead { max-width: 690px; color: #d4dfed; }
.hero-actions { display: flex; flex-wrap: wrap; gap: 11px; margin-top: 32px; }
.gas-ribbon { position: absolute; z-index: 3; left: 50%; bottom: 0; width: min(calc(100% - 48px), var(--max)); transform: translateX(-50%); display: grid; grid-template-columns: repeat(8,1fr); color: var(--navy); background: var(--white); border-radius: 20px 20px 0 0; box-shadow: var(--shadow); overflow: hidden; }
.gas-ribbon a { min-height: 105px; display: flex; flex-direction: column; justify-content: center; padding: 18px 15px; border-right: 1px solid var(--line); }
.gas-ribbon a:last-child { border-right: 0; }
.gas-ribbon strong { color: var(--blue); font-family: Georgia, serif; font-size: 1.2rem; }
.gas-ribbon small { margin-top: 4px; color: var(--muted); font-size: .72rem; line-height: 1.3; }
.gas-ribbon a:hover { background: var(--sky); }

.visual-overview { padding-bottom: 30px; }
.gas-image-grid { display: grid; grid-template-columns: repeat(4,1fr); gap: 14px; }
.gas-image-card { position: relative; min-height: 390px; display: flex; flex-direction: column; justify-content: flex-end; overflow: hidden; padding: 24px; color: var(--white); background: var(--navy); border-radius: 18px; }
.gas-image-card::after { content: ""; position: absolute; inset: 0; background: linear-gradient(180deg,rgba(8,28,58,.03) 28%,rgba(8,28,58,.92) 100%); }
.gas-image-card img { position: absolute; inset: 0; height: 100%; object-fit: contain; background: var(--navy); }
.gas-image-card span, .gas-image-card strong { position: relative; z-index: 1; }
.gas-image-card span { margin-bottom: 5px; color: #a9eff5; font-size: .68rem; font-weight: 850; letter-spacing: .09em; text-transform: uppercase; }
.gas-image-card strong { max-width: 230px; font-size: 1rem; line-height: 1.35; }

.intro-band { padding-block: 55px; background: var(--white); }
.intro-grid { display: grid; grid-template-columns: 1.1fr .9fr; align-items: center; gap: 70px; }
.intro-grid h2 { margin-bottom: 0; font-size: clamp(2rem,3.5vw,3.3rem); }
.intro-grid p { margin-bottom: 0; color: var(--muted); }

.stage-explorer { display: grid; grid-template-columns: 270px 1fr; gap: 24px; }
.stage-tabs { display: grid; align-content: start; gap: 10px; }
.stage-tab { position: relative; min-height: 92px; display: grid; grid-template-columns: 38px 1fr; align-items: center; gap: 12px; padding: 18px; border: 1px solid var(--line); border-radius: 16px; background: var(--white); text-align: left; cursor: pointer; }
.stage-tab span { display: grid; place-items: center; width: 34px; height: 34px; color: var(--blue); background: var(--sky); border-radius: 50%; font-size: .73rem; font-weight: 850; }
.stage-tab strong { color: var(--navy); font-size: .91rem; }
.stage-tab small { display: block; margin-top: 3px; color: var(--muted); font-size: .7rem; }
.stage-tab:hover, .stage-tab.active { color: var(--white); background: var(--blue); border-color: var(--blue); box-shadow: 0 14px 38px rgba(20,87,217,.22); }
.stage-tab.active span, .stage-tab:hover span { color: var(--blue); background: var(--white); }
.stage-tab.active strong, .stage-tab:hover strong, .stage-tab.active small, .stage-tab:hover small { color: var(--white); }
.stage-panel { overflow: hidden; background: var(--white); border: 1px solid var(--line); border-radius: var(--radius); }
.stage-panel[hidden] { display: none; }
.stage-panel.active { display: grid; grid-template-columns: 1.05fr .95fr; min-height: 545px; }
.stage-photo { width: 100%; height: auto; min-height: 0; max-height: none; align-self: center; object-fit: contain; background: var(--mist); }
.stage-copy { padding: 42px; }
.stage-copy h3 { font-size: clamp(2rem,3.3vw,3rem); }
.stage-copy > p { color: var(--muted); }
.info-box { margin-top: 26px; padding: 20px 22px; background: var(--mist); border-radius: 14px; }
.info-box strong { display: block; margin-bottom: 9px; color: var(--navy); font-size: .79rem; letter-spacing: .06em; text-transform: uppercase; }
.info-box ul { margin: 0; padding-left: 19px; color: #536b88; font-size: .84rem; }
.info-box li + li { margin-top: 5px; }
.stage-copy .link { margin-top: 26px; }

.gas-grid { display: grid; grid-template-columns: repeat(4,1fr); gap: 15px; }
.gas-card { min-height: 255px; padding: 28px; background: var(--white); border: 1px solid var(--line); border-radius: 18px; }
.gas-symbol { display: inline-grid; place-items: center; min-width: 58px; height: 58px; padding: 0 12px; color: var(--white); background: var(--blue); border-radius: 15px; font-family: Georgia, serif; font-size: 1.15rem; font-weight: 700; }
.gas-card:nth-child(2n) .gas-symbol { background: var(--cyan); }
.gas-card:nth-child(3n) .gas-symbol { background: var(--navy-2); }
.gas-card:nth-child(4n) .gas-symbol { background: var(--orange); }
.gas-card h3 { margin-top: 32px; font-size: 1.35rem; }
.gas-card p { margin-bottom: 0; color: var(--muted); font-size: .84rem; }

.feature-products { display: grid; grid-template-columns: repeat(3,minmax(0,1fr)); gap: 16px; }
.feature-product { display: flex; flex-direction: column; overflow: hidden; border-radius: 20px; background: var(--navy); }
.feature-product:first-child { grid-row: auto; }
.feature-product img { width: 100%; height: auto; aspect-ratio: 16/9; object-fit: contain; background: var(--mist); }
.feature-overlay { flex: 1; min-height: 128px; padding: 22px 24px 24px; color: var(--white); background: var(--navy); }
.feature-overlay span { color: #9fdde8; font-size: .71rem; font-weight: 850; letter-spacing: .08em; text-transform: uppercase; }
.feature-overlay h3 { margin: 8px 0 0; color: var(--white); font-size: 1.35rem; }
.feature-product:first-child .feature-overlay { padding: 22px 24px 24px; }
.feature-product:first-child .feature-overlay h3 { font-size: 1.35rem; }

.service-grid { display: grid; grid-template-columns: repeat(4,1fr); gap: 14px; }
.service-card { min-height: 245px; padding: 27px; color: var(--white); background: rgba(255,255,255,.075); border: 1px solid rgba(255,255,255,.13); border-radius: 17px; }
.service-card span { color: var(--cyan); font-size: .76rem; font-weight: 850; }
.service-card h3 { margin-top: 52px; font-family: inherit; font-size: 1.15rem; font-weight: 780; letter-spacing: -.02em; }
.service-card p { margin-bottom: 0; font-size: .83rem; }

.standards { display: grid; grid-template-columns: .9fr 1.1fr; gap: 80px; align-items: start; }
.standard-list { border-top: 1px solid var(--line); }
.standard-row { display: grid; grid-template-columns: 130px 1fr; gap: 24px; padding: 24px 0; border-bottom: 1px solid var(--line); }
.standard-row strong { color: var(--blue); }
.standard-row p { margin-bottom: 0; color: var(--muted); font-size: .86rem; }
.note { margin-top: 24px; padding: 18px 20px; color: #526b87; background: var(--sky); border-radius: 12px; font-size: .8rem; }

.certificate-section { background: var(--white); }
.certificate-intro { display: grid; grid-template-columns: 1.08fr .92fr; align-items: end; gap: 80px; margin-bottom: 50px; }
.certificate-intro h2 { margin-bottom: 0; }
.certificate-intro > div:last-child > p { margin-bottom: 19px; }
.quality-points { display: flex; flex-wrap: wrap; gap: 8px; }
.quality-points span { padding: 8px 11px; color: #46607c; background: var(--mist); border: 1px solid var(--line); border-radius: 999px; font-size: .72rem; font-weight: 760; }
.certificate-grid { display: grid; grid-template-columns: repeat(4,1fr); gap: 16px; }
.certificate-card { overflow: hidden; background: var(--white); border: 1px solid var(--line); border-radius: 18px; box-shadow: 0 10px 34px rgba(8,28,58,.06); transition: transform .25s ease, box-shadow .25s ease, border-color .25s ease; }
.certificate-card:hover { transform: translateY(-5px); border-color: #a9c2e7; box-shadow: 0 20px 50px rgba(8,28,58,.13); }
.certificate-preview { height: 225px; display: grid; place-items: center; padding: 15px; background: linear-gradient(145deg,#eef3f8,#f8fafc); border-bottom: 1px solid var(--line); }
.certificate-preview img { width: 100%; height: 100%; object-fit: contain; filter: drop-shadow(0 8px 12px rgba(8,28,58,.16)); }
.certificate-info { min-height: 150px; display: flex; flex-direction: column; padding: 20px; }
.certificate-info small { color: var(--blue); font-size: .7rem; font-weight: 850; letter-spacing: .08em; }
.certificate-info strong { margin-top: 9px; color: var(--navy); font-size: .92rem; line-height: 1.35; }
.certificate-info b { margin-top: auto; padding-top: 19px; color: var(--blue); font-size: .75rem; }
.certificate-note { display: grid; grid-template-columns: 96px 1fr auto; align-items: center; gap: 20px; margin-top: 20px; padding: 22px 24px; background: var(--sky); border: 1px solid #d6e5fb; border-radius: 16px; }
.certificate-note > img { width: 90px; height: 65px; object-fit: contain; }
.certificate-note strong { display: block; color: var(--navy); }
.certificate-note p { margin: 4px 0 0; color: var(--muted); font-size: .8rem; }

.cta { padding-block: 82px; color: var(--white); background: var(--blue); }
.cta-grid { display: grid; grid-template-columns: 1.15fr .85fr; align-items: center; gap: 60px; }
.cta h2 { margin-bottom: 13px; color: var(--white); }
.cta p { max-width: 680px; margin-bottom: 0; color: #dbe7ff; }
.cta-actions { display: flex; justify-content: flex-end; flex-wrap: wrap; gap: 10px; }

.page-hero { position: relative; min-height: 490px; display: flex; align-items: flex-end; overflow: hidden; color: var(--white); background: var(--navy); }
.page-hero > img { position: absolute; inset: 0; width: 100%; height: 100%; object-fit: contain; object-position: right center; opacity: .58; background: var(--navy); }
.page-hero::after { content: ""; position: absolute; inset: 0; background: linear-gradient(90deg,rgba(8,28,58,.95),rgba(8,28,58,.5)); }
.page-hero-content { position: relative; z-index: 2; max-width: 900px; padding-block: 82px; }
.crumb { margin-bottom: 25px; color: #c8d7e8; font-size: .78rem; }
.crumb a { color: #92ecf4; }
.page-hero h1 { margin-bottom: 18px; color: var(--white); font-size: clamp(2.8rem,6vw,5.4rem); }
.page-hero .lead { max-width: 780px; margin-bottom: 0; color: #d6e0ed; }

.system-chapter { display: grid; grid-template-columns: minmax(260px,.72fr) minmax(0,1.28fr); align-items: center; gap: 56px; padding-block: 80px; border-bottom: 1px solid var(--line); scroll-margin-top: 110px; }
.system-chapter:last-child { border-bottom: 0; }
.system-chapter:nth-child(even) { grid-template-columns: minmax(0,1.28fr) minmax(260px,.72fr); }
.system-chapter:nth-child(even) .chapter-media { order: 2; }
.system-chapter.system-chapter--text-only { grid-template-columns: minmax(0,900px); justify-content: center; }
.chapter-media { position: relative; }
.chapter-media > img { width: 100%; height: auto; max-height: none; aspect-ratio: 16/9; object-fit: contain; background: var(--mist); border-radius: 24px; }
.chapter-number { position: absolute; right: -18px; bottom: -18px; display: grid; place-items: center; width: 78px; height: 78px; color: var(--white); background: var(--blue); border: 7px solid var(--white); border-radius: 50%; font-family: Georgia, serif; font-size: 1.3rem; }
.chapter-copy h2 { font-size: clamp(2.2rem,4vw,3.8rem); }
.chapter-copy > p { color: var(--muted); }
.technical-columns { display: grid; grid-template-columns: 1fr 1fr; gap: 13px; margin-top: 25px; }
.technical-card { padding: 18px; background: var(--mist); border-radius: 13px; }
.technical-card strong { display: block; margin-bottom: 8px; color: var(--navy); font-size: .8rem; }
.technical-card p, .technical-card ul { margin: 0; color: var(--muted); font-size: .78rem; }
.technical-card ul { padding-left: 17px; }

.gas-detail-grid { display: grid; grid-template-columns: repeat(2,1fr); gap: 16px; }
.gas-detail { padding: 34px; border: 1px solid var(--line); border-radius: 20px; background: var(--white); scroll-margin-top: 110px; }
.gas-detail-head { display: flex; align-items: center; gap: 18px; }
.gas-detail-head .gas-symbol { flex: 0 0 auto; }
.gas-detail h2 { margin-bottom: 3px; font-size: 2rem; }
.gas-detail-head span { color: var(--muted); font-size: .78rem; }
.gas-detail > p { margin: 25px 0; color: var(--muted); }
.fact-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 9px; }
.fact { padding: 14px; background: var(--mist); border-radius: 10px; }
.fact strong { display: block; color: var(--navy); font-size: .73rem; text-transform: uppercase; }
.fact span { display: block; margin-top: 5px; color: var(--muted); font-size: .76rem; }
.responsive-table { overflow-x: auto; border: 1px solid var(--line); border-radius: 16px; }
table { width: 100%; border-collapse: collapse; min-width: 850px; }
th, td { padding: 18px 20px; border-bottom: 1px solid var(--line); text-align: left; vertical-align: top; }
th { color: var(--navy); background: var(--sky); font-size: .78rem; }
td { color: var(--muted); font-size: .81rem; }
tbody tr:last-child td { border-bottom: 0; }

.filters { display: flex; flex-wrap: wrap; gap: 9px; margin-bottom: 35px; }
.filter { min-height: 43px; padding: 0 17px; border: 1px solid var(--line); border-radius: 999px; background: var(--white); cursor: pointer; font-size: .78rem; font-weight: 780; }
.filter:hover, .filter.active { color: var(--white); background: var(--blue); border-color: var(--blue); }
.products { display: grid; grid-template-columns: repeat(3,1fr); gap: 18px; }
.product { overflow: hidden; background: var(--white); border: 1px solid var(--line); border-radius: 18px; box-shadow: 0 10px 35px rgba(8,28,58,.06); }
.product[hidden] { display: none; }
.product > img { aspect-ratio: 4/3; object-fit: contain; background: var(--mist); }
.product-body { padding: 23px; }
.product-category { display: block; margin-bottom: 10px; color: var(--blue); font-size: .7rem; font-weight: 850; letter-spacing: .1em; text-transform: uppercase; }
.product h3 { font-family: inherit; font-size: 1.08rem; font-weight: 800; line-height: 1.25; letter-spacing: -.02em; }
.product-body > p { color: var(--muted); font-size: .82rem; }
.product details { margin-top: 18px; border-top: 1px solid var(--line); }
.product summary { padding-top: 16px; color: var(--blue); cursor: pointer; font-size: .8rem; font-weight: 820; }
.product details div { padding-top: 12px; color: var(--muted); font-size: .77rem; }
.product details ul { margin: 7px 0 0; padding-left: 18px; }
.product details li + li { margin-top: 4px; }
.visual-note { margin-top: 28px; color: var(--muted); font-size: .78rem; }

.product-index { display: grid; grid-template-columns: repeat(4,1fr); margin-bottom: 28px; background: var(--white); border: 1px solid var(--line); border-radius: 17px; overflow: hidden; }
.product-section-head { grid-template-columns: minmax(0,780px); margin-bottom: 32px; }
.product-section-head .lead { margin-bottom: 0; }
.product-index a { min-height: 66px; display: flex; align-items: center; gap: 11px; padding: 13px 15px; border-right: 1px solid var(--line); border-bottom: 1px solid var(--line); color: #49627e; font-size: .75rem; font-weight: 760; line-height: 1.35; }
.product-index a:nth-child(4n) { border-right: 0; }
.product-index a:nth-last-child(-n+3) { border-bottom: 0; }
.product-index a:hover { color: var(--blue); background: var(--sky); }
.product-index span { flex: 0 0 auto; display: grid; place-items: center; width: 30px; height: 30px; color: var(--blue); background: var(--sky); border-radius: 50%; font-size: .65rem; }
.product-groups { display: grid; grid-template-columns: repeat(3,minmax(0,1fr)); align-items: stretch; gap: 18px; }
.product-group { min-width: 0; display: flex; flex-direction: column; overflow: hidden; background: var(--white); border: 1px solid var(--line); border-radius: 18px; box-shadow: 0 10px 35px rgba(8,28,58,.06); scroll-margin-top: 110px; }
.product-group-media { position: relative; height: 150px; display: grid; place-items: center; padding: 16px 24px; background: linear-gradient(145deg,#edf2f7,#f8fafc); border-bottom: 1px solid var(--line); }
.product-group-media img { width: 100%; height: 100%; max-width: 260px; max-height: 112px; margin: auto; object-fit: contain; }
.product-group-media > span { position: absolute; top: 13px; right: 14px; padding: 6px 9px; color: var(--blue); background: rgba(255,255,255,.9); border: 1px solid var(--line); border-radius: 999px; font-size: .62rem; font-weight: 850; letter-spacing: .08em; }
.product-group-body { flex: 1; display: flex; flex-direction: column; padding: 24px; }
.product-group-body h2 { margin-bottom: 13px; font-family: inherit; font-size: 1.36rem; font-weight: 820; line-height: 1.2; letter-spacing: -.02em; }
.product-group-body > p:not(.product-category):not(.product-feature-title) { color: var(--muted); font-size: .88rem; line-height: 1.6; }
.product-feature-title { margin: 3px 0 0; color: var(--navy); font-size: .76rem; font-weight: 820; }
.product-scope { display: flex; flex-wrap: wrap; gap: 7px; margin-top: 9px; }
.product-scope span { padding: 7px 9px; color: #49627e; background: var(--mist); border-radius: 7px; font-size: .68rem; font-weight: 720; }
.product-group details { margin-top: auto; padding-top: 20px; border-top: 1px solid var(--line); }
.product-group summary { color: var(--blue); cursor: pointer; font-size: .79rem; font-weight: 820; }
.product-group details div { padding-top: 11px; color: var(--muted); font-size: .77rem; }
.product-group details ul { margin: 0; padding-left: 18px; }
.product-group details li + li { margin-top: 4px; }
.product-visual-note { margin-top: 24px; padding: 20px 22px; background: var(--white); border: 1px solid var(--line); border-radius: 14px; }
.product-visual-note strong { display: block; color: var(--navy); font-size: .78rem; }
.product-visual-note p { margin: 6px 0 0; color: var(--muted); font-size: .77rem; }
.product-visual-note .link { font-size: inherit; }

.services-list { display: grid; grid-template-columns: repeat(2,1fr); gap: 16px; }
.service-detail { min-height: 300px; padding: 34px; background: var(--white); border: 1px solid var(--line); border-radius: 18px; }
.service-detail span { display: inline-grid; place-items: center; width: 42px; height: 42px; color: var(--blue); background: var(--sky); border-radius: 50%; font-weight: 850; }
.service-detail h3 { margin-top: 40px; font-size: 1.65rem; }
.service-detail p { color: var(--muted); font-size: .86rem; }
.service-detail ul { padding-left: 18px; color: var(--muted); font-size: .8rem; }
.process { display: grid; grid-template-columns: repeat(5,1fr); border-top: 1px solid rgba(255,255,255,.18); }
.process-step { min-height: 230px; padding: 28px 22px; border-right: 1px solid rgba(255,255,255,.18); }
.process-step:last-child { border-right: 0; }
.process-step span { color: var(--cyan); font-weight: 850; }
.process-step h3 { margin-top: 48px; font-family: inherit; font-size: 1rem; font-weight: 780; letter-spacing: 0; }
.process-step p { margin-bottom: 0; font-size: .78rem; }

.about { display: grid; grid-template-columns: 1.18fr .82fr; gap: 60px; align-items: start; }
.about.about--text-only { grid-template-columns: minmax(0,900px); justify-content: center; }
.about-copy p { color: var(--muted); font-size: 1rem; }
.about-photo { position: sticky; top: 125px; }
.about-photo img { max-height: 410px; object-fit: contain; background: var(--mist); border-radius: 22px; }
.principles { display: grid; grid-template-columns: repeat(3,1fr); gap: 15px; }
.principle { min-height: 260px; padding: 29px; color: var(--white); background: var(--navy-2); border-radius: 17px; }
.principle:nth-child(2) { background: var(--blue); }
.principle:nth-child(3) { color: var(--navy); background: var(--sky); }
.principle span { font-size: .75rem; font-weight: 850; }
.principle h3 { margin-top: 60px; color: inherit; font-size: 1.55rem; }
.principle p { margin-bottom: 0; color: inherit; opacity: .78; font-size: .83rem; }

.contact { display: grid; grid-template-columns: .8fr 1.2fr; gap: 70px; }
.contact-items { border-top: 1px solid var(--line); }
.contact-item { padding: 20px 0; border-bottom: 1px solid var(--line); }
.contact-item small { display: block; color: var(--muted); font-size: .7rem; font-weight: 850; letter-spacing: .1em; text-transform: uppercase; }
.contact-item a, .contact-item strong { display: inline-block; margin-top: 6px; color: var(--navy); font-size: 1.02rem; }
.contact-item a:hover { color: var(--blue); }
.brief { padding: 40px; color: var(--white); background: var(--navy); border-radius: 22px; }
.brief h2 { color: var(--white); font-size: 2.65rem; }
.brief > p { color: #afc0d6; }
.brief ul { margin: 26px 0 0; padding: 0; list-style: none; }
.brief li { padding: 13px 0; border-bottom: 1px solid rgba(255,255,255,.16); color: #d2deed; font-size: .84rem; }
.brief li::before { content: "✓"; margin-right: 11px; color: var(--cyan); font-weight: 900; }
.brief .btn { margin-top: 28px; }

.footer { color: #a7b8cc; background: #05142b; }
.footer-main { display: grid; grid-template-columns: 1.35fr .7fr 1fr; gap: 70px; padding-block: 70px; }
.footer .logo { width: fit-content; padding: 10px 14px; background: var(--white); border-radius: 14px; }
.footer .logo img { width: 170px; height: 122px; }
.footer .logo-text strong { color: var(--white); }
.footer .logo-text small { color: #8ba6c7; }
.footer-about { max-width: 470px; margin: 22px 0 0; font-size: .84rem; }
.footer-col h3 { margin-bottom: 19px; color: var(--white); font-family: inherit; font-size: .75rem; letter-spacing: .1em; text-transform: uppercase; }
.footer-col a, .footer-col span { display: block; width: fit-content; margin: 8px 0; font-size: .82rem; }
.footer-col a:hover { color: var(--cyan); }
.footer-bottom { display: flex; justify-content: space-between; gap: 25px; padding-block: 21px; border-top: 1px solid rgba(255,255,255,.1); color: #7187a1; font-size: .72rem; }
.footer-bottom a:hover { color: var(--cyan); }

@media (max-width: 1100px) {
  .menu-button { display: block; }
  .main-nav { position: fixed; inset: 138px 24px auto; display: none; flex-direction: column; align-items: stretch; padding: 14px; background: var(--white); border: 1px solid var(--line); border-radius: 18px; box-shadow: var(--shadow); }
  .main-nav.open { display: flex; }
  .main-nav > a { padding: 12px 13px; }
  .main-nav .nav-cta { margin: 8px 0 0; text-align: center; }
  .gas-ribbon { grid-template-columns: repeat(4,1fr); }
  .gas-ribbon a { min-height: 78px; }
  .hero-content { padding-bottom: 235px; }
  .stage-explorer { grid-template-columns: 220px 1fr; }
  .stage-panel.active { grid-template-columns: 1fr; }
  .stage-photo { max-height: none; }
  .gas-grid { grid-template-columns: repeat(2,1fr); }
  .feature-products { grid-template-columns: 1fr 1fr; }
  .feature-product:first-child { grid-column: 1 / -1; grid-row: auto; }
  .service-grid { grid-template-columns: repeat(2,1fr); }
  .products { grid-template-columns: repeat(2,1fr); }
  .product-groups { grid-template-columns: repeat(2,1fr); }
  .certificate-grid { grid-template-columns: repeat(2,1fr); }
  .product-index { grid-template-columns: repeat(2,1fr); }
  .product-index a:nth-child(4n) { border-right: 1px solid var(--line); }
  .product-index a:nth-child(2n) { border-right: 0; }
  .product-index a:nth-last-child(-n+3) { border-bottom: 1px solid var(--line); }
  .product-index a:last-child { border-bottom: 0; }
  .process { grid-template-columns: repeat(3,1fr); }
  .gas-image-grid { grid-template-columns: repeat(2,1fr); }
  .process-step { border-bottom: 1px solid rgba(255,255,255,.18); }
}

@media (max-width: 760px) {
  .wrap { width: min(calc(100% - 28px), var(--max)); }
  .topline .wrap { justify-content: center; }
  .topline .wrap > span { display: none; }
  .topline-links { gap: 13px; font-size: .69rem; }
  .header-row { min-height: 84px; }
  .logo img { width: 106px; height: 74px; }
  .logo-text strong { font-size: .84rem; }
  .logo-text small { font-size: .56rem; }
  .main-nav { inset: 120px 14px auto; }
  .section { padding-block: 78px; }
  .section-head, .intro-grid, .standards, .certificate-intro, .cta-grid, .about, .contact { grid-template-columns: 1fr; gap: 28px; }
  .hero { min-height: 790px; align-items: flex-start; }
  .hero::after { background: linear-gradient(rgba(8,28,58,.92),rgba(8,28,58,.57)); }
  .hero-content { padding: 70px 0 330px; }
  h1 { font-size: clamp(2.8rem,14vw,4.7rem); }
  h2 { font-size: clamp(2.1rem,10vw,3.4rem); }
  .gas-ribbon { width: calc(100% - 28px); grid-template-columns: repeat(2,1fr); }
  .gas-ribbon a { min-height: 65px; padding: 11px 14px; }
  .gas-ribbon strong { font-size: 1rem; }
  .intro-band { padding-block: 45px; }
  .stage-explorer { grid-template-columns: 1fr; }
  .stage-tabs { grid-template-columns: repeat(2,1fr); }
  .stage-tab { min-height: 80px; grid-template-columns: 30px 1fr; padding: 13px; }
  .stage-tab span { width: 29px; height: 29px; }
  .stage-tab small { display: none; }
  .stage-copy { padding: 27px 22px; }
  .gas-grid, .gas-image-grid, .feature-products, .service-grid, .gas-detail-grid, .products, .services-list, .principles { grid-template-columns: 1fr; }
  .certificate-grid, .product-groups, .product-index { grid-template-columns: 1fr; }
  .product-group-media { height: 145px; }
  .product-index a, .product-index a:nth-child(2n), .product-index a:nth-child(4n), .product-index a:nth-last-child(-n+3) { border-right: 0; border-bottom: 1px solid var(--line); }
  .product-index a:last-child { border-bottom: 0; }
  .certificate-preview { height: 205px; }
  .certificate-note { grid-template-columns: 74px 1fr; }
  .certificate-note > img { width: 70px; height: 50px; }
  .certificate-note .link { grid-column: 1 / -1; }
  .gas-image-card { min-height: 320px; }
  .feature-products { grid-template-rows: none; }
  .feature-product:first-child { grid-column: auto; }
  .standard-row { grid-template-columns: 1fr; gap: 7px; }
  .cta-actions { justify-content: flex-start; }
  .page-hero { min-height: 430px; }
  .system-chapter { grid-template-columns: 1fr; gap: 36px; padding-block: 62px; }
  .system-chapter:nth-child(even) { grid-template-columns: 1fr; }
  .system-chapter:nth-child(even) .chapter-media { order: 0; }
  .technical-columns, .fact-grid { grid-template-columns: 1fr; }
  .chapter-number { right: 12px; }
  .process { grid-template-columns: 1fr; }
  .process-step { min-height: 190px; border-right: 0; }
  .about-photo { position: static; }
  .brief { padding: 28px 22px; }
  .brief h2 { font-size: 2.15rem; }
  .footer-main { grid-template-columns: 1fr; gap: 37px; }
  .footer-bottom { flex-direction: column; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { transition-duration: .01ms !important; }
}