/* ============================================================
   其美国际 QIMEIGUOJI — Shared Design System
   Monochrome / restrained / editorial (black & white)
   ============================================================ */

:root{
  /* palette — black & white, tonal grays only */
  --paper:      #FFFFFF;   /* clean white base */
  --paper-2:    #F4F4F2;   /* alt section bg */
  --paper-3:    #ECECEA;   /* deeper band / slot fill */
  --white:      #FFFFFF;
  --ink:        #0C0C0C;   /* near-black */
  --ink-2:      #2C2C2C;
  --muted:      #6E6E6C;   /* secondary text */
  --faint:      #A2A2A0;
  --line:       rgba(12,12,12,.14);
  --line-soft:  rgba(12,12,12,.07);

  /* accents collapsed to monochrome — names kept for compatibility */
  --jade:       #0C0C0C;   /* primary = black */
  --jade-deep:  #0A0A0A;   /* darkest band */
  --jade-soft:  #8C8C8A;   /* mid gray */
  --jade-tint:  #F1F1EF;   /* light gray fill */
  --gold:       #5E5E5C;   /* secondary = mid-dark gray */
  --gold-soft:  #B8B8B4;   /* light gray (on dark bands) */
  --gold-tint:  #F1F1EF;
  --accent-soft:#9C9C9A;   /* subtle gray accent for headline lines */

  /* type */
  --sans: "Noto Sans SC", -apple-system, "PingFang SC", "Microsoft YaHei", sans-serif;
  --display: "Space Grotesk", "Noto Sans SC", sans-serif;

  /* layout */
  --maxw: 1280px;
  --gutter: clamp(20px, 5vw, 80px);
  --nav-h: 76px;
  --radius: 4px;
  --ease: cubic-bezier(.2,.7,.2,1);
}

*{ box-sizing:border-box; margin:0; padding:0; }
html{ scroll-behavior:smooth; -webkit-text-size-adjust:100%; }
body{
  font-family:var(--sans);
  background:var(--paper);
  color:var(--ink);
  line-height:1.7;
  font-weight:400;
  font-size:17px;
  -webkit-font-smoothing:antialiased;
  text-rendering:optimizeLegibility;
  overflow-x:hidden;
}
img{ max-width:100%; display:block; }
a{ color:inherit; text-decoration:none; }
ul{ list-style:none; }

/* ---------- type utilities ---------- */
.eyebrow{
  font-family:var(--display);
  font-size:12px; font-weight:500;
  letter-spacing:.32em; text-transform:uppercase;
  color:var(--muted);
  display:inline-flex; align-items:center; gap:.85em;
}
.eyebrow::before{
  content:""; width:30px; height:1px; background:currentColor; opacity:.55;
}
.eyebrow.gold{ color:var(--muted); }
.eyebrow.gold::before{ background:currentColor; }
.eyebrow.center{ justify-content:center; }
.eyebrow.center::after{
  content:""; width:30px; height:1px; background:currentColor; opacity:.5;
}

h1,h2,h3,h4{ font-weight:700; line-height:1.12; letter-spacing:-.01em; color:var(--ink); }
.display{ font-size:clamp(40px, 6.2vw, 92px); font-weight:700; line-height:1.04; letter-spacing:-.02em; }
.h2{ font-size:clamp(30px, 4vw, 54px); line-height:1.1; }
.h3{ font-size:clamp(22px, 2.4vw, 32px); }
.lede{ font-size:clamp(18px, 1.5vw, 22px); color:var(--ink-2); line-height:1.75; font-weight:300; }
.muted{ color:var(--muted); }
.num{ font-family:var(--display); font-weight:500; letter-spacing:-.02em; font-feature-settings:"tnum"; }

/* ---------- layout helpers ---------- */
.wrap{ max-width:var(--maxw); margin:0 auto; padding-inline:var(--gutter); }
section{ position:relative; }
.section-pad{ padding-block:clamp(72px, 10vw, 150px); }
.band-2{ background:var(--paper-2); }
.band-ink{ background:var(--ink); color:var(--paper); }
.band-jade{ background:var(--jade-deep); color:#ECECEB; }

.grid{ display:grid; gap:clamp(20px,3vw,40px); }
.cols-2{ grid-template-columns:repeat(2,1fr); }
.cols-3{ grid-template-columns:repeat(3,1fr); }
.cols-4{ grid-template-columns:repeat(4,1fr); }

/* ---------- buttons ---------- */
.btn{
  display:inline-flex; align-items:center; gap:.6em;
  font-family:var(--sans); font-size:15px; font-weight:500;
  padding:15px 30px; border-radius:999px;
  border:1px solid transparent; cursor:pointer;
  transition:all .35s var(--ease); white-space:nowrap;
}
.btn .arr{ transition:transform .35s var(--ease); }
.btn:hover .arr{ transform:translateX(4px); }
.btn-primary{ background:var(--ink); color:#fff; }
.btn-primary:hover{ background:#000; transform:translateY(-2px); box-shadow:0 14px 30px -14px rgba(0,0,0,.5); }
.btn-ghost{ border-color:var(--line); color:var(--ink); background:transparent; }
.btn-ghost:hover{ border-color:var(--ink); background:var(--ink); color:#fff; }
.btn-light{ background:#fff; color:var(--ink); }
.btn-light:hover{ background:#fff; transform:translateY(-2px); box-shadow:0 14px 30px -14px rgba(0,0,0,.4); }
.btn-gold{ background:#fff; color:var(--ink); }
.btn-gold:hover{ background:#fff; transform:translateY(-2px); box-shadow:0 14px 30px -14px rgba(0,0,0,.4); }

/* ---------- header / nav ---------- */
.nav{
  position:fixed; inset:0 0 auto 0; height:var(--nav-h); z-index:100;
  display:flex; align-items:center;
  background:rgba(255,255,255,.82); backdrop-filter:blur(14px);
  border-bottom:1px solid transparent; transition:border-color .4s, background .4s;
}
.nav.scrolled{ border-bottom-color:var(--line-soft); background:rgba(255,255,255,.94); }
.nav .wrap{ display:flex; align-items:center; justify-content:space-between; width:100%; }
.nav-logo{ display:flex; align-items:center; gap:12px; }
.nav-logo img{ height:30px; width:auto; }
.nav-links{ display:flex; align-items:center; gap:clamp(18px,2.4vw,40px); }
.nav-links a{
  font-size:15px; color:var(--ink-2); position:relative; padding-block:6px;
  transition:color .3s;
}
.nav-links a::after{
  content:""; position:absolute; left:0; bottom:0; height:1.5px; width:0;
  background:var(--jade); transition:width .35s var(--ease);
}
.nav-links a:hover, .nav-links a.active{ color:var(--ink); }
.nav-links a.active::after, .nav-links a:hover::after{ width:100%; }
.nav-cta{ display:flex; align-items:center; gap:14px; }
.nav-burger{ display:none; flex-direction:column; gap:5px; background:none; border:none; cursor:pointer; padding:8px; }
.nav-burger span{ width:24px; height:2px; background:var(--ink); transition:.3s; }

/* mobile menu */
.mobile-menu{
  position:fixed; inset:var(--nav-h) 0 0 0; z-index:99;
  background:var(--paper); padding:40px var(--gutter);
  transform:translateY(-100%); opacity:0; pointer-events:none;
  transition:transform .45s var(--ease), opacity .45s;
  display:flex; flex-direction:column; gap:6px;
}
.mobile-menu.open{ transform:translateY(0); opacity:1; pointer-events:auto; }
.mobile-menu a{ font-size:26px; font-weight:500; padding:14px 0; border-bottom:1px solid var(--line-soft); }

/* ---------- footer ---------- */
.footer{ background:var(--ink); color:#B4B4B2; padding-block:clamp(60px,7vw,96px) 32px; }
.footer a{ color:#B4B4B2; transition:color .3s; }
.footer a:hover{ color:#fff; }
.footer-top{ display:grid; grid-template-columns:1.6fr 1fr 1fr; gap:40px; padding-bottom:54px; border-bottom:1px solid rgba(255,255,255,.1); }
.footer-brand img{ height:34px; filter:invert(1) brightness(1.6); margin-bottom:20px; }
.footer h5{ font-size:13px; letter-spacing:.16em; text-transform:uppercase; color:#fff; margin-bottom:20px; font-weight:600; }
.footer ul li{ margin-bottom:12px; font-size:15px; }
.footer-bottom{ display:flex; justify-content:space-between; flex-wrap:wrap; gap:12px; padding-top:28px; font-size:13px; color:#8A8A88; }

/* ---------- cards & misc ---------- */
.card{ background:var(--white); border:1px solid var(--line-soft); border-radius:8px; transition:transform .4s var(--ease), box-shadow .4s var(--ease), border-color .4s; }
.card:hover{ transform:translateY(-5px); box-shadow:0 24px 50px -28px rgba(12,12,12,.28); border-color:var(--line); }
.rule{ height:1px; background:var(--line); border:0; }
.tag{ display:inline-block; font-size:12px; letter-spacing:.1em; padding:5px 12px; border-radius:999px; border:1px solid var(--line); color:var(--muted); }
.tag.jade{ color:var(--ink); border-color:var(--line); background:var(--jade-tint); }
.tag.gold{ color:var(--muted); border-color:var(--line); background:var(--gold-tint); }

.media-img{ display:block; width:100%; height:100%; object-fit:cover; background:var(--paper-3); }

/* ---------- reveal animation ---------- */
.reveal{ opacity:0; transform:translateY(24px); transition:opacity .9s var(--ease), transform .9s var(--ease); }
.reveal.in{ opacity:1; transform:none; }
.reveal[data-d="1"]{ transition-delay:.08s; }
.reveal[data-d="2"]{ transition-delay:.16s; }
.reveal[data-d="3"]{ transition-delay:.24s; }
.reveal[data-d="4"]{ transition-delay:.32s; }
@media (prefers-reduced-motion: reduce){
  .reveal{ opacity:1; transform:none; transition:none; }
  html{ scroll-behavior:auto; }
}

/* ---------- responsive ---------- */
@media (max-width: 980px){
  .footer-top{ grid-template-columns:1fr 1fr; }
  .cols-4{ grid-template-columns:repeat(2,1fr); }
}
@media (max-width: 760px){
  body{ font-size:16px; }
  .nav-links, .nav-cta .btn{ display:none; }
  .nav-burger{ display:flex; }
  .cols-2,.cols-3,.cols-4{ grid-template-columns:1fr; }
  .footer-top{ grid-template-columns:1fr; gap:32px; }
}

/* ---------- faq accordion ---------- */
.faq-section {
  background: var(--paper-2);
}
.faq-list {
  max-width: 820px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 16px;
}
.faq-item {
  background: var(--white);
  border: 1px solid var(--line-soft);
  border-radius: 8px;
  overflow: hidden;
  transition: border-color .3s, box-shadow .3s;
}
.faq-item:hover {
  border-color: var(--line);
}
.faq-item.active {
  border-color: var(--ink);
  box-shadow: 0 10px 30px -15px rgba(0,0,0,0.05);
}
.faq-trigger {
  width: 100%;
  padding: 24px 28px;
  background: none;
  border: none;
  text-align: left;
  font-family: var(--sans);
  font-size: 18px;
  font-weight: 600;
  color: var(--ink);
  display: flex;
  justify-content: space-between;
  align-items: center;
  cursor: pointer;
  user-select: none;
}
.faq-icon {
  font-size: 20px;
  color: var(--muted);
  transition: transform .35s var(--ease);
  line-height: 1;
}
.faq-item.active .faq-icon {
  transform: rotate(45deg);
}
.faq-content {
  max-height: 0;
  overflow: hidden;
  transition: max-height .35s var(--ease);
}
.faq-content-inner {
  padding: 0 28px 24px 28px;
  font-size: 15.5px;
  color: var(--ink-2);
  line-height: 1.65;
}
.faq-content-inner p {
  margin-bottom: 12px;
}
.faq-content-inner p:last-child {
  margin-bottom: 0;
}
.faq-content-inner ul, .faq-content-inner ol {
  margin-left: 20px;
  margin-bottom: 12px;
}
.faq-content-inner li {
  margin-bottom: 6px;
}