/* =========================================================
   GSS New Website — Homepage Styles
   Design: modernized industrial B2B.
   Color & font spec CONFIRMED by user (2026-08-19):
     Logo Color 1 : rgb(250,190,80)  -> #FABE50  (amber / gold, primary)
     Logo Color 2 : rgb(76,73,72)    -> #4C4948  (charcoal, ink & dark sections)
     VI 辅助色 1   : rgb(246,171,80)  -> #F6AB50  (deeper amber)
     VI 辅助色 2   : rgb(229,230,230) -> #E5E6E6  (light gray)
   Fonts:
     中文站     : 阿里巴巴普惠体 (Alibaba PuHui)
     英文站正文 : Dax
     英文站标题 : Impact
   (Per-glyph fallback lets the same stack serve both languages.)
   ========================================================= */
:root {
  /* ===== GSS Brand Colors (confirmed) ===== */
  --brand:      #FABE50;   /* Logo Color 1 — amber / gold (primary) */
  --brand-deep: #F6AB50;   /* VI 辅助色 1 — deeper amber (gradients / hover) */
  --ink:        #4C4948;   /* Logo Color 2 — charcoal (text & dark sections) */
  --ink-deep:   #3A3736;   /* derived shade of charcoal (footer / contrast) */
  --paper:      #E5E6E6;   /* VI 辅助色 2 — light gray (tint bgs, dividers) */

  /* Neutrals */
  --white: #FFFFFF;
  --bg:    #FBFAF8;        /* warm off-white to pair with gold */
  --body:  #5A5754;        /* readable body text (warm gray) */
  --muted: #908C89;
  --line:  #E7E4E1;

  /* ===== Fonts ===== */
  --font-head: "Impact", "Haettenschweiler", "阿里巴巴普惠体", "Alibaba PuHui", "Arial Narrow", sans-serif;
  --font-body: "Dax", "Daxline OT", "阿里巴巴普惠体", "Alibaba PuHui", "Helvetica Neue", Arial, sans-serif;

  --radius: 14px;
  --radius-sm: 10px;
  --shadow: 0 10px 30px rgba(76,73,72,.10);
  --shadow-lg: 0 18px 50px rgba(76,73,72,.18);
  --maxw: 1200px;
}

* { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  font-family: var(--font-body);
  color: var(--body);
  background: var(--bg);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}
h1, h2, h3, h4, h5 { font-family: var(--font-head); font-weight: 400; letter-spacing: .3px; }
img, video { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }
.container { width: 100%; max-width: var(--maxw); margin: 0 auto; padding: 0 24px; }

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex; align-items: center; justify-content: center;
  gap: 8px; padding: 12px 22px; border-radius: 999px;
  font-weight: 600; font-size: 15px; cursor: pointer;
  transition: transform .15s ease, box-shadow .15s ease, background .15s ease, color .15s ease;
  border: 1.5px solid transparent; white-space: nowrap;
}
.btn-primary { background: var(--brand); color: var(--ink); }
.btn-primary:hover { background: var(--brand-deep); transform: translateY(-2px); box-shadow: var(--shadow); }
.btn-ghost { background: rgba(255,255,255,.12); color: #fff; border-color: rgba(255,255,255,.6); }
.btn-ghost:hover { background: rgba(255,255,255,.22); }
.btn-outline { background: transparent; color: var(--brand); border-color: var(--brand); }
.btn-outline:hover { background: rgba(250,190,80,.14); }
.btn-lg { padding: 15px 30px; font-size: 16px; }

/* ---------- Header ---------- */
.site-header {
  position: fixed; top: 0; left: 0; right: 0; z-index: 50;
  transition: background .25s ease, box-shadow .25s ease;
  padding: 18px 0;
}
.site-header.scrolled {
  background: rgba(255,255,255,.96);
  box-shadow: 0 4px 20px rgba(0,0,0,.06);
  backdrop-filter: blur(8px);
}
.nav-inner { display: flex; align-items: center; justify-content: space-between; gap: 20px; }
.brand { display: flex; flex-direction: column; align-items: flex-start; line-height: 1; }
.brand-logo { height: 44px; width: auto; align-self: flex-start; display: block; }
.logo-dark { display: block; }
.logo-light { display: none; }
/* Hero header is transparent over dark video: drop-shadow keeps light logo readable */
.site-header:not(.scrolled) .logo-dark { filter: drop-shadow(0 2px 5px rgba(0,0,0,.55)); }
.site-header.scrolled .logo-dark { display: none; }
.site-header.scrolled .logo-light { display: block; }
.footer-brand .brand-logo { height: 48px; display: block; }
.main-nav { display: flex; gap: 26px; }
.main-nav a { color: rgba(255,255,255,.92); font-weight: 700; font-size: 15px; letter-spacing: .3px; position: relative; padding: 4px 0; }
.site-header.scrolled .main-nav a { color: var(--ink); }
.main-nav a::after { content:""; position:absolute; left:0; bottom:-2px; height:2px; width:0; background: var(--brand); transition: width .2s ease; }
.main-nav a:hover::after { width: 100%; }
.nav-cta { padding: 10px 20px; }
.nav-toggle { display: none; flex-direction: column; gap: 5px; background: none; border: 0; cursor: pointer; }
.nav-toggle span { width: 24px; height: 2px; background: #fff; border-radius: 2px; }
.site-header.scrolled .nav-toggle span { background: var(--ink); }

/* ---------- Hero ---------- */
.hero { position: relative; min-height: 100vh; display: flex; align-items: center; overflow: hidden; color: #fff; }
.hero-video { position: absolute; inset: 0; width: 100%; height: 100%; object-fit: cover; z-index: 0; }
.hero-overlay {
  position: absolute; inset: 0; z-index: 1;
  background: linear-gradient(105deg, rgba(58,55,54,.88) 0%, rgba(76,73,72,.62) 45%, rgba(58,55,54,.26) 100%);
}
.hero-content { position: relative; z-index: 2; padding-top: 90px; max-width: 860px; }
.hero-eyebrow { font-weight: 700; letter-spacing: 3px; text-transform: uppercase; color: var(--brand); margin-bottom: 18px; }
.hero-title { font-size: clamp(34px, 5.4vw, 64px); line-height: 1.05; color: #fff; }
.hero-lead { margin: 22px 0 34px; font-size: clamp(16px, 1.6vw, 19px); color: rgba(255,255,255,.9); max-width: 620px; }
.hero-actions { display: flex; gap: 14px; flex-wrap: wrap; }
.hero-scroll { position: absolute; bottom: 26px; left: 50%; transform: translateX(-50%); width: 26px; height: 42px; border: 2px solid rgba(255,255,255,.6); border-radius: 14px; z-index: 2; }
.hero-scroll::after { content:""; position:absolute; top:8px; left:50%; transform:translateX(-50%); width:4px; height:8px; background:var(--brand); border-radius:2px; animation: scrolldot 1.6s infinite; }
@keyframes scrolldot { 0%{opacity:0;top:8px} 40%{opacity:1} 80%{opacity:0;top:22px} 100%{opacity:0} }

/* ---------- Sections ---------- */
.section { padding: 96px 0; }
.section-alt { background: var(--white); }
.section-dark { background: var(--ink-deep); color: rgba(255,255,255,.85); }

/* ---------- Explore GSS — gold CTA band (distinct from dark footer) ---------- */
/* Explore GSS — gold band, 2-col: left intro / right tabbed feed (distinct from dark footer) */
.gold-cta { background: var(--brand); color: var(--ink-deep); }
.gold-cta .kicker { color: var(--ink-deep); opacity: 1; font-weight: 800; }
.explore-split { display: grid; grid-template-columns: 1fr 1.15fr; gap: 52px; align-items: start; }
.explore-intro h2 { color: var(--ink-deep); font-size: clamp(28px, 3.4vw, 40px); margin: 10px 0 16px; }
.explore-intro p { color: var(--ink); font-weight: 500; font-size: 16px; line-height: 1.7; margin-bottom: 16px; }
.intro-stats { list-style: none; display: flex; gap: 26px; margin: 22px 0 26px; padding: 0; flex-wrap: wrap; }
.intro-stats li { display: flex; flex-direction: column; }
.intro-stats strong { font-family: var(--font-head); font-size: 30px; color: var(--ink-deep); line-height: 1; }
.intro-stats span { font-size: 12.5px; color: var(--ink); margin-top: 6px; opacity: .85; }
.gold-cta .btn-primary { background: var(--ink-deep); color: #fff; }
.gold-cta .btn-primary:hover { background: #2a2726; }
/* right: tabbed feed */
.tab-head { display: flex; gap: 10px; margin-bottom: 18px; }
.tab-btn { font-family: var(--font-body); font-size: 15px; font-weight: 700; padding: 10px 22px; border-radius: 999px; border: 1.5px solid rgba(76,73,72,.35); background: transparent; color: var(--ink-deep); cursor: pointer; transition: all .2s ease; }
.tab-btn:hover { border-color: var(--ink-deep); }
.tab-btn.active { background: var(--ink-deep); color: #fff; border-color: var(--ink-deep); }
.tab-panel { display: none; }
.tab-panel.active { display: block; animation: feedFade .25s ease; }
@keyframes feedFade { from { opacity: 0; transform: translateY(6px); } to { opacity: 1; transform: none; } }
.feed-item { display: flex; align-items: center; gap: 14px; background: rgba(255,255,255,.5); border: 1px solid rgba(76,73,72,.16); border-radius: var(--radius-sm); padding: 10px 14px 10px 10px; margin-bottom: 12px; text-decoration: none; transition: transform .18s ease, box-shadow .18s ease, border-color .18s ease, background .18s ease; }
.feed-item:last-child { margin-bottom: 0; }
.feed-item:hover { transform: translateX(4px); background: rgba(255,255,255,.72); box-shadow: 0 10px 24px rgba(58,55,54,.16); border-color: var(--ink-deep); }
.feed-thumb { flex: 0 0 100px; width: 100px; height: 100px; border-radius: 10px; object-fit: cover; display: block; background: rgba(76,73,72,.10); }
.feed-body { flex: 1 1 auto; min-width: 0; display: flex; flex-direction: column; gap: 4px; }
.feed-meta { font-size: 12px; font-weight: 700; color: var(--ink); letter-spacing: .3px; }
.feed-meta.tag { align-self: flex-start; color: var(--ink-deep); background: rgba(76,73,72,.12); border-radius: 5px; padding: 2px 8px; font-size: 11px; letter-spacing: .4px; text-transform: uppercase; }
.feed-title { font-size: 14px; color: var(--ink-deep); font-weight: 600; line-height: 1.4; display: -webkit-box; -webkit-line-clamp: 2; -webkit-box-orient: vertical; overflow: hidden; }
.feed-summary { font-size: 12.5px; color: rgba(76,73,72,.82); line-height: 1.45; display: -webkit-box; -webkit-line-clamp: 1; -webkit-box-orient: vertical; overflow: hidden; }
.feed-go { flex: 0 0 auto; color: var(--ink-deep); font-size: 16px; font-weight: 700; }
.feed-item:hover .feed-go { color: var(--brand-deep); }
.section-head { max-width: 720px; margin: 0 auto 52px; text-align: center; }
.kicker { display: inline-block; font-size: 13px; font-weight: 700; letter-spacing: 2px; text-transform: uppercase; color: var(--brand); margin-bottom: 12px; }
.kicker.light { color: var(--brand); }
.section-head h2 { font-size: clamp(28px, 3.6vw, 44px); color: var(--ink); margin-top: 4px; }
.section-dark .section-head h2 { color: #fff; }
.section-lead { margin-top: 14px; font-size: 17px; color: var(--muted); }
.section-dark .section-lead { color: rgba(255,255,255,.7); }

/* ---------- Solutions cards ---------- */
.card-grid { display: grid; gap: 26px; }
.solutions-grid { grid-template-columns: repeat(3, 1fr); }
.sol-card {
  background: var(--white); border-radius: var(--radius); overflow: hidden;
  box-shadow: var(--shadow); border: 1px solid var(--line);
  transition: transform .2s ease, box-shadow .2s ease; display: flex; flex-direction: column;
}
.sol-card:hover { transform: translateY(-6px); box-shadow: var(--shadow-lg); }
.sol-media { height: 200px; background-size: cover; background-position: center; }
.sol-body { padding: 22px 24px 26px; }
.sol-body h3 { font-size: 21px; color: var(--ink); margin-bottom: 8px; }
.sol-body p { font-size: 15px; }
.card-link { display: inline-block; margin-top: 14px; color: var(--brand); font-weight: 700; font-size: 14px; }

/* ---------- Products pillars ---------- */
.pillars { display: grid; grid-template-columns: repeat(3, 1fr); gap: 22px; }
.pillar { background: var(--bg); border: 1px solid var(--line); border-radius: var(--radius-sm); padding: 28px 26px; transition: border-color .2s ease, transform .2s ease; }
.pillar:hover { border-color: var(--brand); transform: translateY(-4px); }
.pillar-no { font-size: 13px; font-weight: 800; color: var(--brand); letter-spacing: 1px; }
.pillar h3 { font-size: 21px; color: var(--ink); margin: 8px 0 8px; }
.pillar p { font-size: 15px; }

/* ---------- Stats ---------- */
.stats { display: grid; grid-template-columns: repeat(4, 1fr); gap: 20px; margin-bottom: 56px; }
.stat { text-align: center; padding: 26px 16px; background: rgba(250,190,80,.16); border-radius: var(--radius-sm); border: 1px solid rgba(250,190,80,.30); }
.stat strong { display: block; font-family: var(--font-head); font-size: clamp(28px, 4vw, 42px); color: var(--ink); }
.stat span { font-size: 14px; color: var(--muted); }

/* ---------- Projects ---------- */
.project-grid { grid-template-columns: repeat(3, 1fr); }
.proj-card { background: var(--white); border-radius: var(--radius); overflow: hidden; box-shadow: var(--shadow); border: 1px solid var(--line); transition: transform .2s ease, box-shadow .2s ease; }
.proj-card:hover { transform: translateY(-6px); box-shadow: var(--shadow-lg); }
.proj-media { height: 210px; background-size: cover; background-position: center; }
.proj-body { padding: 22px 24px 26px; }
.proj-tag { display: inline-block; font-size: 12px; font-weight: 700; color: var(--ink); background: rgba(250,190,80,.22); padding: 4px 12px; border-radius: 999px; margin-bottom: 12px; }
.proj-body h3 { font-size: 19px; color: var(--ink); margin-bottom: 8px; }
.center { text-align: center; margin-top: 44px; }

/* ---------- Explore (dark) ---------- */
/* (Explore GSS card styles live in the gold-cta block above) */

/* ---------- Footer ---------- */
.site-footer { background: var(--ink-deep); color: rgba(255,255,255,.75); padding: 64px 0 24px; }
.footer-grid { display: grid; grid-template-columns: 1.6fr 1fr 1fr 1fr; gap: 36px; }
.footer-brand .brand-mark { color: #fff; }
.footer-brand p { margin: 14px 0 18px; font-size: 14px; max-width: 280px; }
.footer-contact { display: flex; flex-direction: column; gap: 8px; }
.footer-contact-line { font-size: 14px; color: rgba(255,255,255,.78); text-decoration: none; transition: color .15s ease; }
.footer-contact-line:hover { color: var(--brand); }
.footer-col h5 { color: var(--brand); font-size: 16px; margin-bottom: 14px; letter-spacing: .5px; }
.footer-col a { display: block; font-size: 14px; padding: 5px 0; color: rgba(255,255,255,.7); transition: color .15s ease; }
.footer-col a:hover { color: var(--brand); }
.footer-bottom { display: flex; justify-content: space-between; align-items: center; margin-top: 44px; padding-top: 22px; border-top: 1px solid rgba(255,255,255,.12); font-size: 13px; flex-wrap: wrap; gap: 10px; }
.social a { margin-left: 18px; color: rgba(255,255,255,.7); }
.social a:hover { color: var(--brand); }

/* ---------- Responsive ---------- */
@media (max-width: 980px) {
  .solutions-grid, .project-grid, .pillars { grid-template-columns: repeat(2, 1fr); }
  .stats { grid-template-columns: repeat(2, 1fr); }
  .explore-split { grid-template-columns: 1fr; gap: 34px; }
  .footer-grid { grid-template-columns: 1fr 1fr; }
}
@media (max-width: 720px) {
  .main-nav {
    position: absolute; top: 100%; left: 0; right: 0;
    flex-direction: column; gap: 0; background: #fff; padding: 10px 24px 18px;
    box-shadow: var(--shadow); display: none;
  }
  .main-nav.open { display: flex; }
  .main-nav a { color: var(--ink); padding: 12px 0; border-bottom: 1px solid var(--line); }
  .nav-cta { display: none; }
  .nav-toggle { display: flex; }
  .solutions-grid, .project-grid, .pillars, .stats, .footer-grid { grid-template-columns: 1fr; }
  .section { padding: 64px 0; }
}