/* ─────────────────────────────────────────
   TOKENS
───────────────────────────────────────── */
:root {
  --ink:      #0f0f0d;
  --ink-mid:  #2a2a26;
  --ink-mute: #6b6b65;
  --ink-faint:#a8a89e;
  --green:    #2a6644;
  --green-dk: #1c4830;
  --green-lt: #e6f0eb;
  --green-hl: #3d8c5f;
  --sand:     #f5f2eb;
  --white:    #ffffff;
  --border:   rgba(15,15,13,.1);
  --border-w: rgba(255,255,255,.12);
  --ff:       'PingFang SC','Hiragino Sans GB','Microsoft YaHei',system-ui,sans-serif;
  --r:        5px;
  --rl:       10px;
}

/* ─────────────────────────────────────────
   RESET + BASE
───────────────────────────────────────── */
*{margin:0;padding:0;box-sizing:border-box;}
html{scroll-behavior:smooth;font-size:15px;}
body{font-family:var(--ff);color:var(--ink);background:#fff;line-height:1.7;}
a{color:inherit;text-decoration:none;}
img{max-width:100%;display:block;}
button,select,input,textarea{font-family:var(--ff);}

/* ─────────────────────────────────────────
   LANG SWITCH
───────────────────────────────────────── */
.lang-en .zh{display:none;}
.lang-zh .en{display:none;}

/* ─────────────────────────────────────────
   NAV
───────────────────────────────────────── */
nav{
  position:fixed;top:0;left:0;right:0;z-index:200;
  height:64px;display:flex;align-items:center;
  transition:background .3s,box-shadow .3s;
}
nav.over-dark{background:transparent;}
nav.over-light{
  background:rgba(255,255,255,.93);
  backdrop-filter:blur(14px);
  box-shadow:0 1px 0 var(--border);
}
.nav-inner{
  max-width:1200px;margin:0 auto;padding:0 40px;
  width:100%;display:flex;align-items:center;justify-content:space-between;
}
.nav-logo{display:flex;align-items:center;gap:10px;cursor:pointer;}
.logo-img{width:40px;height:40px;border-radius:8px;object-fit:contain;}
.logo-text{font-size:20px;font-weight:600;letter-spacing:.02em;}
.nav-links{display:flex;gap:28px;list-style:none;}
.nav-links a{
  font-size:13px;color:inherit;
  opacity:.7;transition:opacity .2s;
}
.nav-links a:hover{opacity:1;}
.nav-right{display:flex;align-items:center;gap:16px;}
.nav-lang{
  font-size:12px;padding:5px 14px;
  border:1px solid rgba(255,255,255,.3);
  border-radius:20px;cursor:pointer;
  transition:all .2s;
}
nav.over-light .nav-links a{color:var(--ink);}
nav.over-light .logo-text{color:var(--ink);}
nav.over-light .nav-lang{border-color:var(--border);color:var(--ink-mute);}
nav.over-dark .nav-links a,
nav.over-dark .logo-text{color:#fff;}
nav.over-dark .nav-lang{color:rgba(255,255,255,.7);}
.nav-cta{
  background:var(--green);color:#fff;
  padding:7px 18px;border-radius:var(--r);
  font-size:13px;font-weight:500;
  transition:background .2s;
}
.nav-cta:hover{background:var(--green-hl);}
.nav-hamburger{display:none;cursor:pointer;flex-direction:column;gap:5px;}
.nav-hamburger span{
  display:block;width:22px;height:1.5px;
  background:currentColor;transition:.2s;
}

/* ─────────────────────────────────────────
   HERO — dark immersive
───────────────────────────────────────── */
.hero{
  min-height:100vh;
  position:relative;overflow:hidden;
  display:flex;align-items:center;
  background:var(--ink);
  color:#fff;
}
.hero-bg-img{
  position:absolute;inset:0;z-index:0;
  background-size:cover;background-position:center;
  opacity:.12;
  filter:brightness(0.7);
}
.hero-noise{
  position:absolute;inset:0;z-index:0;
  background-image:url("data:image/svg+xml,%3Csvg viewBox='0 0 200 200' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.75' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)' opacity='0.04'/%3E%3C/svg%3E");
  opacity:.5;
}
.hero-glow{
  position:absolute;inset:0;z-index:0;
  background:radial-gradient(ellipse 70% 60% at 65% 50%, rgba(42,102,68,.45) 0%, transparent 70%);
}
.hero-inner{
  position:relative;z-index:1;
  max-width:900px;margin:0 auto;padding:100px 40px 80px;
  width:100%;
}
.hero-eyebrow{
  display:inline-flex;align-items:center;gap:8px;
  background:rgba(255,255,255,.08);
  border:1px solid rgba(255,255,255,.15);
  border-radius:20px;
  padding:5px 14px;font-size:12px;
  letter-spacing:.06em;color:rgba(255,255,255,.8);
  margin-bottom:22px;
}
.hero-eyebrow-dot{
  width:6px;height:6px;border-radius:50%;
  background:#4caf7a;
  box-shadow:0 0 6px rgba(76,175,122,.8);
}
h1.hero-h1{
  font-size:clamp(38px,5vw,62px);
  font-weight:300;line-height:1.12;
  letter-spacing:-.03em;
  margin-bottom:16px;
}
h1.hero-h1 em{
  font-style:normal;
  color:#5fc98a;
}
h1.hero-h1 strong{
  font-weight:500;
}
.hero-p{
  font-size:17px;color:rgba(255,255,255,.65);
  line-height:1.9;max-width:700px;
  margin-bottom:28px;
}
.hero-btns{display:flex;gap:12px;flex-wrap:wrap;}
.btn-hero-primary{
  background:var(--green);color:#fff;
  padding:13px 30px;border-radius:var(--r);
  font-size:14px;font-weight:500;
  transition:background .2s,transform .15s;display:inline-block;
}
.btn-hero-primary:hover{background:var(--green-hl);transform:translateY(-1px);}
.btn-hero-ghost{
  background:transparent;color:rgba(255,255,255,.8);
  padding:13px 30px;border-radius:var(--r);
  font-size:14px;
  border:1px solid rgba(255,255,255,.2);
  transition:border-color .2s,color .2s;display:inline-block;
}
.btn-hero-ghost:hover{border-color:rgba(255,255,255,.5);color:#fff;}

/* ─────────────────────────────────────────
   ARTICLE CONTENT (case detail pages)
───────────────────────────────────────── */
.article{background:var(--sand);}
.article .w{max-width:860px;}
.article-title{
  font-size:clamp(24px,3.5vw,34px);
  font-weight:300;line-height:1.3;
  letter-spacing:-.01em;margin-bottom:32px;
}
.article-sub{font-size:14px;color:var(--ink-mute);margin-bottom:10px;}
.article-section{margin-bottom:36px;}
.article-section h3{
  font-size:18px;font-weight:600;
  margin-bottom:12px;color:var(--ink);
}
.article-section p{
  font-size:14px;color:var(--ink-mute);
  line-height:1.85;margin-bottom:10px;
}
.article-section ul{margin:12px 0;padding-left:20px;}
.article-section li{
  font-size:14px;color:var(--ink-mute);
  line-height:1.85;margin-bottom:6px;
}
.article-section li strong{color:var(--ink);}
.article-section ol{margin:12px 0;padding-left:20px;}
.article-section ol li{
  font-size:14px;color:var(--ink-mute);
  line-height:1.85;margin-bottom:10px;
}
.article-section ol li strong{color:var(--ink);}

/* project info box */
.project-info{
  background:#fff;
  border:1px solid var(--border);
  border-radius:var(--rl);
  padding:24px 28px;
  margin:24px 0;
}
.project-info h4{
  font-size:14px;font-weight:600;
  margin-bottom:12px;color:var(--green);
  letter-spacing:.04em;
}
.project-info-grid{
  display:grid;grid-template-columns:1fr 1fr;gap:8px 24px;
}
.pi-item{
  font-size:13px;color:var(--ink-mute);
  padding:4px 0;
}
.pi-item strong{
  color:var(--ink);font-weight:500;
}

/* data tables */
.data-table{
  width:100%;border-collapse:collapse;
  margin:20px 0;border:1px solid var(--border);
  border-radius:var(--rl);overflow:hidden;
}
.data-table th{
  background:var(--green-dk);color:#fff;
  font-size:12px;font-weight:500;
  padding:12px 14px;text-align:left;
  letter-spacing:.03em;
}
.data-table td{
  padding:10px 14px;font-size:13px;
  border-bottom:1px solid var(--border);
  color:var(--ink-mute);
}
.data-table tr:last-child td{border-bottom:none;}
.data-table td:first-child{font-weight:500;color:var(--ink);}
.data-table .pass{color:var(--green);font-weight:600;}
.data-table tr:nth-child(even){background:rgba(230,240,235,.4);}
.data-table tr:nth-child(odd){background:#fff;}

/* quote highlight box */
.highlight-box{
  background:var(--green-lt);
  border-left:3px solid var(--green);
  padding:20px 24px;
  margin:24px 0;
  border-radius:0 var(--r) var(--r) 0;
}
.highlight-box p{
  font-size:15px;color:var(--ink-mid);
  line-height:1.8;margin:0;
}

/* ─────────────────────────────────────────
   CTA BANNER
───────────────────────────────────────── */
.cta-banner{background:var(--ink);text-align:center;padding:60px 0;}
.cta-banner h2{color:#fff;margin-bottom:12px;}
.cta-banner p{color:rgba(255,255,255,.5);font-size:15px;margin-bottom:28px;}

/* ─────────────────────────────────────────
   FOOTER
───────────────────────────────────────── */
footer{
  background:var(--ink);
  border-top:1px solid rgba(255,255,255,.07);
  padding:28px 0;
}
.footer-inner{
  max-width:1200px;margin:0 auto;padding:0 40px;
  display:flex;justify-content:space-between;align-items:center;
  gap:20px;flex-wrap:wrap;
}
.footer-brand{font-size:13px;font-weight:600;color:#fff;}
.footer-copy{font-size:12px;color:rgba(255,255,255,.3);margin-top:4px;}
.footer-links{display:flex;gap:20px;}
.footer-links a{
  font-size:12px;color:rgba(255,255,255,.4);
  transition:color .2s;
}
.footer-links a:hover{color:#fff;}

/* ─────────────────────────────────────────
   MOBILE NAV MENU
───────────────────────────────────────── */
#mobileMenu{
  display:none;
  position:fixed;inset:0;z-index:190;
  background:var(--ink);
  flex-direction:column;
  align-items:center;justify-content:center;
  gap:32px;
}
#mobileMenu.open{display:flex;}
#mobileMenu a{
  font-size:20px;color:#fff;
  opacity:.8;
}
#mobileMenu a:hover{opacity:1;}

/* ─────────────────────────────────────────
   ANIMATIONS
───────────────────────────────────────── */
.reveal{
  opacity:0;transform:translateY(24px);
  transition:opacity .7s ease, transform .7s ease;
}
.reveal.visible{opacity:1;transform:translateY(0);}
.reveal-delay-1{transition-delay:.1s;}
.reveal-delay-2{transition-delay:.2s;}
.reveal-delay-3{transition-delay:.3s;}
.reveal-delay-4{transition-delay:.4s;}
.reveal-delay-5{transition-delay:.5s;}

/* ─────────────────────────────────────────
   RESPONSIVE
───────────────────────────────────────── */
@media(max-width:768px){
  nav{height:56px;}
  .nav-links,.nav-cta{display:none;}
  .nav-hamburger{display:flex;}
  section{padding:56px 0;}
  .w{padding:0 20px;}
  .nav-inner{padding:0 20px;}
  .hero-inner{padding:80px 20px 60px;}
  .hero-h1{font-size:30px;}
  .hero-p{font-size:15px;}
  .article-title{font-size:24px;}
  .project-info-grid{grid-template-columns:1fr;}
  .footer-inner{flex-direction:column;align-items:flex-start;gap:16px;}
}