:root {
  --bg: #ffffff;
  --bg-soft: #f4f7f6;
  --bg-tint: #eef3f1;
  --surface: #ffffff;
  --text: #16221f;
  --text-dim: #4a5a55;
  --text-faint: #7c8a85;
  --brand: #0e7a5f;
  --brand-dark: #0a5c47;
  --brand-accent: #12a37e;
  --navy: #15263a;
  --border: #e1e8e5;
  --border-soft: #eef2f0;
  --shadow-sm: 0 1px 3px rgba(16,40,33,.08), 0 6px 18px rgba(16,40,33,.06);
  --shadow-md: 0 8px 28px rgba(16,40,33,.10);
  --radius: 14px;
  --radius-lg: 20px;
  --maxw: 1200px;
  --font-body: "Inter", system-ui, -apple-system, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  --font-display: "Space Grotesk", "Inter", system-ui, sans-serif;
  --ease: cubic-bezier(.22,.61,.36,1);
}

* { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; scroll-padding-top: 84px; }
body {
  font-family: var(--font-body);
  color: var(--text);
  background: var(--bg);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}
img { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }
.container { max-width: var(--maxw); margin: 0 auto; padding: 0 24px; }

/* ---------- Header / Nav ---------- */
.site-header {
  position: sticky; top: 0; z-index: 50;
  background: rgba(255,255,255,.86);
  backdrop-filter: saturate(160%) blur(12px);
  border-bottom: 1px solid var(--border-soft);
}
.nav { display: flex; align-items: center; justify-content: space-between; height: 64px; }
.brand { display: flex; align-items: center; gap: 10px; font-family: var(--font-display); font-weight: 700; font-size: 18px; color: var(--navy); }
.brand-mark { width: 22px; height: 22px; border-radius: 6px; background: linear-gradient(135deg, var(--brand), var(--brand-accent)); box-shadow: 0 2px 8px rgba(14,122,95,.35); }
.brand-name { letter-spacing: .5px; }
.nav-links { display: flex; gap: 26px; }
.nav-links a { font-size: 14.5px; font-weight: 500; color: var(--text-dim); transition: color .2s; }
.nav-links a:hover, .nav-links a.active { color: var(--brand); }
.nav-actions { display: flex; align-items: center; gap: 12px; }
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  font-size: 14.5px; font-weight: 600; padding: 10px 20px; border-radius: 10px;
  cursor: pointer; border: 1px solid transparent; transition: all .2s var(--ease);
}
.btn-primary { background: var(--brand); color: #fff; box-shadow: 0 4px 14px rgba(14,122,95,.28); }
.btn-primary:hover { background: var(--brand-dark); transform: translateY(-1px); }
.btn-ghost { background: transparent; color: var(--brand); border-color: var(--border); }
.btn-ghost:hover { border-color: var(--brand); background: var(--bg-tint); }
.btn-lg { padding: 13px 28px; font-size: 15.5px; }
.nav-toggle { display: none; flex-direction: column; gap: 5px; background: none; border: 0; cursor: pointer; padding: 6px; }
.nav-toggle span { width: 24px; height: 2px; background: var(--navy); border-radius: 2px; }

/* ---------- Hero ---------- */
.hero { position: relative; overflow: hidden; color: #fff; }
.hero-bg { position: absolute; inset: 0; }
.hero-bg img { width: 100%; height: 100%; object-fit: cover; }
.hero-bg::after { content: ""; position: absolute; inset: 0; background: linear-gradient(105deg, rgba(10,40,32,.88) 0%, rgba(10,40,32,.62) 45%, rgba(10,40,32,.30) 100%); }
.hero-inner { position: relative; z-index: 2; max-width: var(--maxw); margin: 0 auto; padding: 120px 24px 110px; }
.eyebrow { display: inline-block; font-size: 13px; font-weight: 600; letter-spacing: .14em; text-transform: uppercase; color: var(--brand-accent); margin-bottom: 18px; }
.hero h1 { font-family: var(--font-display); font-size: clamp(34px, 5.2vw, 60px); line-height: 1.08; font-weight: 700; letter-spacing: -.5px; color: #fff; text-shadow: 0 2px 18px rgba(0,0,0,.45); }
.hero h1 .grad { background: linear-gradient(120deg,#ffffff,#9ff0d6,#36e0bd); -webkit-background-clip: text; background-clip: text; -webkit-text-fill-color: transparent; color: transparent; }
.hero p.lead { margin: 22px 0 32px; max-width: 640px; font-size: 18px; color: #eaf6f1; text-shadow: 0 1px 8px rgba(0,0,0,.4); }
.hero-cta { display: flex; gap: 14px; flex-wrap: wrap; }
.hero-cta .btn-ghost { color: #fff; border-color: rgba(255,255,255,.4); }
.hero-cta .btn-ghost:hover { background: rgba(255,255,255,.12); border-color: #fff; }
.hero-stats { display: flex; gap: 40px; margin-top: 46px; flex-wrap: wrap; }
.hero-stats .stat strong { display: block; font-family: var(--font-display); font-size: 30px; color: #fff; }
.hero-stats .stat span { font-size: 13.5px; color: #bfe6da; }

/* ---------- Sections ---------- */
.section { padding: 84px 0; }
.section-alt { background: var(--bg-soft); }
.section-head { max-width: 760px; margin: 0 auto 46px; text-align: center; }
.section-head .eyebrow { color: var(--brand); }
.section-head h2 { font-family: var(--font-display); font-size: clamp(26px, 3.4vw, 38px); color: var(--navy); line-height: 1.15; letter-spacing: -.4px; }
.section-head p { margin-top: 14px; font-size: 17px; color: var(--text-dim); }

/* ---------- Module overview grid ---------- */
.modules { display: grid; grid-template-columns: repeat(3, 1fr); gap: 22px; }
.module-card {
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm); transition: all .3s var(--ease); text-align: left;
  display: flex; flex-direction: column; overflow: hidden;
}
.module-card:hover { transform: translateY(-4px); box-shadow: var(--shadow-md); border-color: rgba(14,122,95,.35); }
.module-card .m-icon {
  width: 100%; height: 170px;
  display: flex; align-items: center; justify-content: center; overflow: hidden;
  background: var(--bg-tint);
}
.module-card .m-icon img { width: 100%; height: 100%; object-fit: cover; }
.module-card .m-body { padding: 20px 22px 24px; display: flex; flex-direction: column; gap: 8px; }
.module-card .m-num { font-family: var(--font-display); font-size: 13px; font-weight: 700; color: var(--brand); letter-spacing: .08em; }
.module-card h3 { font-family: var(--font-display); font-size: 19px; color: var(--navy); line-height: 1.3; }
.module-card p { font-size: 14.5px; color: var(--text-dim); line-height: 1.6; flex-grow: 1; }
.module-card .m-link { font-size: 14px; font-weight: 600; color: var(--brand); display: inline-flex; align-items: center; gap: 4px; }

/* ---------- Detail blocks ---------- */
.detail { padding: 72px 0; }
.detail.alt { background: var(--bg-soft); }
.detail-anchor { scroll-margin-top: 84px; }
.detail-head { display: flex; align-items: center; gap: 16px; margin-bottom: 8px; }
.detail-head .num { font-family: var(--font-display); font-size: 15px; font-weight: 700; color: #fff; background: var(--brand); padding: 5px 12px; border-radius: 8px; }
.detail-head h2 { font-family: var(--font-display); font-size: clamp(24px,3.2vw,34px); color: var(--navy); }
.detail-head .tag { font-size: 13px; font-weight: 600; color: var(--brand); border: 1px solid var(--border); padding: 4px 10px; border-radius: 999px; background: var(--bg-tint); }
.detail-intro { max-width: 820px; margin: 14px 0 36px; font-size: 16.5px; color: var(--text-dim); }

.feature-row { display: grid; grid-template-columns: 1fr 1fr; gap: 40px; align-items: center; margin: 0 0 48px; }
.feature-row.reverse .fr-art { order: -1; }
.fr-text h3 { font-family: var(--font-display); font-size: 21px; color: var(--navy); margin-bottom: 12px; }
.fr-text p { font-size: 15.5px; color: var(--text-dim); margin-bottom: 12px; }
.fr-art { border-radius: var(--radius-lg); overflow: hidden; box-shadow: var(--shadow-md); border: 1px solid var(--border); background: var(--surface); }
.fr-art img { width: 100%; height: 100%; object-fit: cover; }

.cards { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
.cards-2 { grid-template-columns: repeat(2, 1fr); }
.cards-4 { grid-template-columns: repeat(4, 1fr); }
.card { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 24px 22px; box-shadow: var(--shadow-sm); transition: all .3s var(--ease); }
.card:hover { transform: translateY(-3px); box-shadow: var(--shadow-md); }
.card .card-icon { width: 46px; height: 46px; border-radius: 11px; background: var(--bg-tint); display: flex; align-items: center; justify-content: center; font-size: 22px; margin-bottom: 14px; overflow: hidden; }
.card .card-icon img { width: 100%; height: 100%; object-fit: cover; }
.card h3 { font-family: var(--font-display); font-size: 17.5px; color: var(--navy); margin-bottom: 8px; }
.card p { font-size: 14.5px; color: var(--text-dim); }
.card img.card-figure { width: 100%; height: 150px; object-fit: cover; border-radius: 10px; margin-bottom: 14px; }

/* numbered steps */
.steps { display: grid; grid-template-columns: repeat(4, 1fr); gap: 20px; counter-reset: step; }
.step { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 24px 20px; position: relative; }
.step .step-num { font-family: var(--font-display); font-size: 26px; font-weight: 700; color: var(--brand-accent); opacity: .35; }
.step h4 { font-family: var(--font-display); font-size: 16.5px; color: var(--navy); margin: 6px 0 8px; }
.step p { font-size: 14px; color: var(--text-dim); }

/* metrics */
.metrics { display: flex; gap: 40px; flex-wrap: wrap; justify-content: center; margin-top: 18px; }
.metric { text-align: center; }
.metric strong { display: block; font-family: var(--font-display); font-size: 34px; color: var(--brand); }
.metric span { font-size: 14px; color: var(--text-dim); }

/* gallery */
.gallery { display: grid; grid-template-columns: repeat(4, 1fr); gap: 14px; margin-top: 24px; }
.gallery img { width: 100%; height: 160px; object-fit: cover; border-radius: 10px; border: 1px solid var(--border); box-shadow: var(--shadow-sm); }

/* case study */
.case { background: var(--surface); border: 1px solid var(--border); border-left: 4px solid var(--brand); border-radius: var(--radius); padding: 24px 26px; box-shadow: var(--shadow-sm); }
.case h4 { font-family: var(--font-display); font-size: 18px; color: var(--navy); margin-bottom: 10px; }
.case ul { list-style: none; display: grid; gap: 8px; }
.case li { font-size: 14.5px; color: var(--text-dim); padding-left: 22px; position: relative; }
.case li::before { content: "▹"; position: absolute; left: 0; color: var(--brand); }

/* CTA */
.cta { position: relative; background: linear-gradient(120deg, var(--brand-dark), var(--brand)); color: #fff; padding: 76px 0; overflow: hidden; }
.cta::after { content:""; position:absolute; inset:0; background: radial-gradient(circle at 80% 20%, rgba(54,224,189,.25), transparent 50%); }
.cta-inner { position: relative; z-index: 2; text-align: center; }
.cta h2 { font-family: var(--font-display); font-size: clamp(26px,3.4vw,38px); margin-bottom: 12px; }
.cta p { font-size: 17px; color: #d8f3ea; margin-bottom: 26px; }
.cta .hero-cta { justify-content: center; }

/* Footer */
.site-footer { background: var(--navy); color: #c7d6cf; padding: 56px 0 28px; }
.footer-grid { display: grid; grid-template-columns: 1.4fr 1fr 1fr 1fr; gap: 30px; }
.footer-brand .brand { color: #fff; margin-bottom: 12px; }
.footer-brand p { font-size: 14px; color: #9fb4ac; max-width: 280px; }
.footer-col h4 { font-size: 14px; font-weight: 700; color: #fff; margin-bottom: 14px; letter-spacing: .04em; }
.footer-col a { display: block; font-size: 14px; color: #a9bdb5; padding: 5px 0; transition: color .2s; }
.footer-col a:hover { color: #fff; }
.footer-bottom { display: flex; justify-content: space-between; margin-top: 38px; padding-top: 20px; border-top: 1px solid rgba(255,255,255,.12); font-size: 13px; color: #8ba097; flex-wrap: wrap; gap: 8px; }

/* reveal animation */
.reveal { opacity: 0; transform: translateY(34px); transition: opacity 1s var(--ease), transform 1s var(--ease); will-change: opacity, transform; }
.reveal.in { opacity: 1; transform: none; }
.reveal[data-delay="1"] { transition-delay: .1s; }
.reveal[data-delay="2"] { transition-delay: .2s; }
.reveal[data-delay="3"] { transition-delay: .3s; }
.reveal[data-delay="4"] { transition-delay: .4s; }
.reveal-left { opacity: 0; transform: translateX(-40px); transition: opacity 1s var(--ease), transform 1s var(--ease); }
.reveal-left.in { opacity: 1; transform: none; }
.reveal-right { opacity: 0; transform: translateX(40px); transition: opacity 1s var(--ease), transform 1s var(--ease); }
.reveal-right.in { opacity: 1; transform: none; }
@media (prefers-reduced-motion: reduce) {
  .reveal, .reveal-left, .reveal-right { opacity: 1 !important; transform: none !important; transition: none !important; }
}

/* responsive */
@media (max-width: 980px) {
  .modules, .cards, .cards-4, .steps, .gallery { grid-template-columns: repeat(2, 1fr); }
  .cards-2 { grid-template-columns: 1fr; }
  .feature-row { grid-template-columns: 1fr; gap: 22px; }
  .feature-row.reverse .fr-art { order: -1; }
  .footer-grid { grid-template-columns: 1fr 1fr; }
}
@media (max-width: 720px) {
  .nav-links { display: none; }
  .nav-toggle { display: flex; }
  .modules, .cards, .cards-2, .cards-4, .steps, .gallery { grid-template-columns: 1fr; }
  .hero-inner { padding: 90px 20px 80px; }
}