/* Quark-style static site */
* { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  color: #1a1a1a;
  background: #ffffff;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}
a { color: inherit; text-decoration: none; }
img { max-width: 100%; display: block; }

/* Header */
.site-header {
  position: sticky; top: 0; z-index: 100;
  background: rgba(255,255,255,0.85);
  backdrop-filter: saturate(180%) blur(14px);
  border-bottom: 1px solid rgba(0,0,0,0.06);
}
.nav {
  max-width: 1200px; margin: 0 auto;
  display: flex; align-items: center; justify-content: space-between;
  padding: 14px 32px;
}
.nav-brand { display: flex; align-items: center; gap: 10px; font-size: 20px; font-weight: 700; color: #2b6bff; }
.nav-brand img { width: 32px; height: 32px; }
.nav-menu { display: flex; align-items: center; gap: 32px; }
.nav-menu a { font-size: 15px; color: #333; font-weight: 500; transition: color .2s; }
.nav-menu a:hover, .nav-menu a.active { color: #2b6bff; }
.nav-right { display: flex; align-items: center; gap: 16px; }
.lang-switch { font-size: 14px; color: #666; }
.lang-switch a { padding: 4px 8px; border-radius: 6px; }
.lang-switch a.active { background: #eef3ff; color: #2b6bff; font-weight: 600; }
.btn {
  display: inline-block; padding: 10px 22px; border-radius: 999px;
  font-size: 14px; font-weight: 600; transition: transform .15s, box-shadow .2s;
  cursor: pointer; border: none;
}
.btn-primary { background: linear-gradient(135deg, #2b6bff, #4a8bff); color: #fff; box-shadow: 0 4px 14px rgba(43,107,255,.35); }
.btn-primary:hover { transform: translateY(-1px); box-shadow: 0 6px 20px rgba(43,107,255,.45); }
.btn-outline { background: transparent; color: #2b6bff; border: 1px solid #2b6bff; }
.btn-outline:hover { background: #eef3ff; }

/* Hero */
.hero {
  position: relative;
  min-height: 92vh;
  display: flex; align-items: center; justify-content: center;
  background: linear-gradient(180deg, #eaf2ff 0%, #f7faff 100%);
  overflow: hidden;
  text-align: center;
  padding: 80px 24px;
}
.hero::before {
  content: ""; position: absolute; inset: 0;
  background: url('https://www.quarkcx.com/assets/images/hero.jpg') center/cover no-repeat;
  opacity: 0.35; z-index: 0;
}
.hero-inner { position: relative; z-index: 1; max-width: 900px; }
.hero-logo { width: 96px; height: 96px; margin: 0 auto 24px; }
.hero h1 {
  font-size: clamp(40px, 6vw, 72px);
  font-weight: 800; letter-spacing: -0.02em;
  background: linear-gradient(135deg, #1a1a1a 0%, #2b6bff 100%);
  -webkit-background-clip: text; background-clip: text; color: transparent;
  margin-bottom: 16px;
}
.hero p.subtitle { font-size: clamp(16px, 2vw, 20px); color: #555; margin-bottom: 12px; }
.hero .cta { margin-top: 32px; display: flex; gap: 16px; justify-content: center; flex-wrap: wrap; }

/* Section base */
section.feature {
  padding: 120px 24px;
  display: flex; align-items: center; justify-content: center;
}
.feature-inner {
  max-width: 1100px; width: 100%;
  display: grid; grid-template-columns: 1fr 1fr; gap: 64px; align-items: center;
}
.feature.reverse .feature-inner { direction: rtl; }
.feature.reverse .feature-text { direction: ltr; }
.feature.reverse .feature-media { direction: ltr; }
.feature-text .eyebrow { color: #2b6bff; font-weight: 600; font-size: 14px; letter-spacing: 0.08em; text-transform: uppercase; margin-bottom: 12px; }
.feature-text h2 { font-size: clamp(28px, 4vw, 44px); font-weight: 700; letter-spacing: -0.01em; margin-bottom: 20px; }
.feature-text p { font-size: 17px; color: #555; margin-bottom: 12px; }
.feature-media img { border-radius: 24px; box-shadow: 0 20px 60px rgba(43,107,255,.12); }
.feature.alt { background: #f7faff; }

/* Sub page hero */
.page-hero {
  padding: 140px 24px 80px;
  text-align: center;
  background: linear-gradient(180deg, #eaf2ff 0%, #ffffff 100%);
}
.page-hero h1 { font-size: clamp(36px, 5vw, 56px); font-weight: 800; margin-bottom: 16px; letter-spacing: -0.02em; }
.page-hero p { font-size: 18px; color: #555; max-width: 680px; margin: 0 auto; }

/* Cards grid */
.container { max-width: 1100px; margin: 0 auto; padding: 80px 24px; }
.cards { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; margin-top: 40px; }
.card {
  background: #fff; border: 1px solid #eef1f6; border-radius: 20px;
  padding: 32px; transition: transform .2s, box-shadow .2s;
}
.card:hover { transform: translateY(-4px); box-shadow: 0 12px 32px rgba(0,0,0,.06); }
.card img { width: 56px; height: 56px; margin-bottom: 20px; border-radius: 14px; }
.card h3 { font-size: 20px; margin-bottom: 10px; }
.card p { color: #666; font-size: 15px; }

/* Download variants */
.download-options {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 20px; margin-top: 40px;
}
.download-card {
  background: linear-gradient(160deg, #ffffff, #f5f9ff);
  border: 1px solid #e5edff; border-radius: 20px;
  padding: 32px; text-align: center;
}
.download-card .icon { font-size: 40px; margin-bottom: 12px; }
.download-card h3 { font-size: 18px; margin-bottom: 8px; }
.download-card p { color: #777; font-size: 14px; margin-bottom: 20px; }

/* FAQ */
.faq-list { max-width: 820px; margin: 40px auto 0; }
.faq-item {
  border: 1px solid #eef1f6; border-radius: 16px;
  padding: 24px 28px; margin-bottom: 16px; background: #fff;
}
.faq-item h3 { font-size: 17px; margin-bottom: 10px; color: #1a1a1a; }
.faq-item p { color: #555; font-size: 15px; }

/* Footer */
.site-footer {
  background: #0f1420; color: #a4a9b8;
  padding: 60px 24px 30px; text-align: center;
}
.site-footer .foot-inner { max-width: 1100px; margin: 0 auto; }
.site-footer h4 { color: #fff; margin-bottom: 12px; }
.foot-links { display: flex; justify-content: center; gap: 28px; flex-wrap: wrap; margin: 20px 0; }
.foot-links a { color: #cfd4e0; font-size: 14px; }
.foot-links a:hover { color: #fff; }
.copyright { font-size: 13px; opacity: .7; margin-top: 20px; border-top: 1px solid rgba(255,255,255,.08); padding-top: 20px; }

/* Responsive */
@media (max-width: 900px) {
  .nav-menu { display: none; }
  .feature-inner { grid-template-columns: 1fr; gap: 40px; }
  .feature.reverse .feature-inner { direction: ltr; }
  .cards { grid-template-columns: 1fr; }
  section.feature { padding: 80px 24px; }
}