/* ============================================================
   STBC — Chengdu Baichuan Electronics Co., Ltd.
   Global stylesheet
   ============================================================ */

:root {
  --navy: #0a1f3c;
  --navy-2: #0e2c52;
  --blue: #1244a8;
  --blue-2: #0b3d91;
  --accent: #00b4d8;
  --accent-dark: #0077b6;
  --ink: #12243a;
  --body: #46586b;
  --muted: #6b7c8f;
  --line: #e1e9f2;
  --bg: #ffffff;
  --bg-soft: #f4f8fc;
  --bg-tint: #eef4fb;
  --white: #ffffff;
  --wa: #25d366;
  --shadow: 0 10px 30px rgba(10, 31, 60, 0.08);
  --shadow-lg: 0 24px 60px rgba(10, 31, 60, 0.16);
  --radius: 14px;
  --radius-sm: 9px;
  --max: 1200px;
  --font-head: "Space Grotesk", "Manrope", system-ui, sans-serif;
  --font-body: "Manrope", system-ui, -apple-system, "Segoe UI", sans-serif;
}

* { margin: 0; padding: 0; box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  font-family: var(--font-body);
  color: var(--body);
  background: var(--bg);
  line-height: 1.7;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
}

img { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }
ul { list-style: none; }

h1, h2, h3, h4 {
  font-family: var(--font-head);
  color: var(--ink);
  line-height: 1.2;
  font-weight: 700;
}

.container {
  width: 100%;
  max-width: var(--max);
  margin: 0 auto;
  padding: 0 24px;
}

.section { padding: 92px 0; }
.section--soft { background: var(--bg-soft); }
.section--tint { background: var(--bg-tint); }
.section--dark { background: var(--navy); color: #c6d6e8; }
.section--dark h2, .section--dark h3 { color: #fff; }

.eyebrow {
  display: inline-block;
  font-family: var(--font-head);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--accent-dark);
  margin-bottom: 16px;
}
.section--dark .eyebrow { color: var(--accent); }

.section-head { max-width: 720px; margin-bottom: 56px; }
.section-head.center { margin-left: auto; margin-right: auto; text-align: center; }
.section-head h2 { font-size: clamp(28px, 3.6vw, 40px); margin-bottom: 18px; }
.section-head p { font-size: 17px; }

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 9px;
  font-family: var(--font-head);
  font-weight: 600;
  font-size: 15px;
  padding: 14px 28px;
  border-radius: 999px;
  border: 1.5px solid transparent;
  cursor: pointer;
  transition: transform .2s ease, box-shadow .2s ease, background .2s ease;
  white-space: nowrap;
}
.btn:hover { transform: translateY(-2px); }
.btn-primary { background: var(--accent); color: #04222e; box-shadow: 0 10px 24px rgba(0,180,216,.28); }
.btn-primary:hover { background: #0fc3e6; }
.btn-blue { background: var(--blue); color: #fff; box-shadow: 0 10px 24px rgba(18,68,168,.28); }
.btn-blue:hover { background: #154fb8; }
.btn-outline { border-color: var(--line); color: var(--ink); background: transparent; }
.btn-outline:hover { border-color: var(--accent); color: var(--accent-dark); }
.btn-light { background: #fff; color: var(--blue); }
.btn-ghost-light { border-color: rgba(255,255,255,.35); color: #fff; }
.btn-ghost-light:hover { background: rgba(255,255,255,.1); border-color: #fff; }
.btn-block { width: 100%; }

/* ---------- Header ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--line);
}
.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 74px;
}
.brand { display: flex; align-items: center; gap: 12px; }
.brand-mark {
  width: 42px; height: 42px;
  border-radius: 11px;
  background: linear-gradient(135deg, var(--blue), var(--accent));
  display: grid; place-items: center;
  color: #fff; font-family: var(--font-head); font-weight: 700; font-size: 17px;
}
.brand-text { display: flex; flex-direction: column; line-height: 1.1; }
.brand-text strong { font-family: var(--font-head); color: var(--ink); font-size: 18px; letter-spacing: .02em; }
.brand-text span { font-size: 11.5px; color: var(--muted); letter-spacing: .06em; }

.main-nav { display: flex; align-items: center; gap: 6px; }
.main-nav > li > a {
  display: block;
  padding: 10px 15px;
  font-size: 15px;
  font-weight: 500;
  color: var(--ink);
  border-radius: 8px;
  transition: color .15s, background .15s;
}
.main-nav > li > a:hover, .main-nav > li > a.active { color: var(--accent-dark); background: var(--bg-tint); }
.nav-cta { margin-left: 12px; }

.has-dropdown { position: relative; }
.dropdown {
  position: absolute;
  top: calc(100% + 10px);
  left: 0;
  min-width: 240px;
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  box-shadow: var(--shadow);
  padding: 8px;
  opacity: 0;
  visibility: hidden;
  transform: translateY(8px);
  transition: all .18s ease;
}
.has-dropdown:hover .dropdown { opacity: 1; visibility: visible; transform: translateY(0); }
.dropdown a {
  display: block;
  padding: 10px 14px;
  border-radius: 7px;
  font-size: 14.5px;
  color: var(--ink);
}
.dropdown a:hover { background: var(--bg-tint); color: var(--accent-dark); }

.nav-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  width: 44px; height: 44px;
}
.nav-toggle span {
  display: block;
  width: 24px; height: 2px;
  background: var(--ink);
  margin: 5px auto;
  transition: .25s;
}

/* ---------- Hero ---------- */
.hero {
  position: relative;
  background: var(--navy);
  color: #d6e4f2;
  overflow: hidden;
}
.hero::before {
  content: "";
  position: absolute; inset: 0;
  background:
    radial-gradient(900px 400px at 78% 10%, rgba(0,180,216,.22), transparent 60%),
    radial-gradient(700px 500px at 10% 90%, rgba(18,68,168,.35), transparent 60%);
}
.hero-grid {
  position: relative;
  display: grid;
  grid-template-columns: 1.05fr .95fr;
  gap: 56px;
  align-items: center;
  padding: 96px 0 104px;
}
.hero-badge {
  display: inline-flex; align-items: center; gap: 8px;
  font-size: 13.5px; font-weight: 600;
  color: #bfe9f4;
  background: rgba(0,180,216,.12);
  border: 1px solid rgba(0,180,216,.3);
  padding: 7px 16px;
  border-radius: 999px;
  margin-bottom: 26px;
}
.hero h1 {
  color: #fff;
  font-size: clamp(34px, 4.6vw, 54px);
  margin-bottom: 22px;
  letter-spacing: -0.01em;
}
.hero h1 em { font-style: normal; color: var(--accent); }
.hero p.lead { font-size: 18px; color: #b9ccdf; margin-bottom: 34px; max-width: 540px; }
.hero-actions { display: flex; flex-wrap: wrap; gap: 14px; margin-bottom: 44px; }
.hero-stats {
  display: grid;
  grid-template-columns: repeat(3, auto);
  gap: 40px;
  justify-content: start;
}
.hero-stat .num { font-family: var(--font-head); font-size: 30px; font-weight: 700; color: #fff; }
.hero-stat .lbl { font-size: 13.5px; color: #93aac2; }

.hero-media {
  position: relative;
  border-radius: 18px;
  overflow: hidden;
  box-shadow: var(--shadow-lg);
}
.hero-media img { width: 100%; height: 460px; object-fit: cover; }
.hero-media::after {
  content: "";
  position: absolute; inset: 0;
  background: linear-gradient(180deg, transparent 55%, rgba(10,31,60,.45));
}

/* ---------- Trust strip ---------- */
.trust-strip { padding: 30px 0; border-bottom: 1px solid var(--line); background: #fff; }
.trust-strip .container { display: flex; flex-wrap: wrap; align-items: center; gap: 18px 40px; justify-content: space-between; }
.trust-label { font-size: 13.5px; font-weight: 600; color: var(--muted); letter-spacing: .04em; }
.trust-logos { display: flex; flex-wrap: wrap; gap: 14px 30px; }
.trust-logos span {
  font-family: var(--font-head);
  font-weight: 600;
  font-size: 16px;
  color: #8a99ab;
}

/* ---------- Product cards ---------- */
.product-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 26px;
}
.product-card {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
  display: flex;
  flex-direction: column;
  transition: transform .25s ease, box-shadow .25s ease, border-color .25s;
}
.product-card:hover { transform: translateY(-6px); box-shadow: var(--shadow); border-color: #cfe0f0; }
.product-card .thumb { aspect-ratio: 1 / 1; overflow: hidden; background: var(--bg-soft); }
.product-card .thumb img { width: 100%; height: 100%; object-fit: cover; transition: transform .4s ease; }
.product-card:hover .thumb img { transform: scale(1.05); }
.product-card .body { padding: 24px; display: flex; flex-direction: column; flex: 1; }
.product-card h3 { font-size: 19px; margin-bottom: 10px; }
.product-card p { font-size: 14.5px; color: var(--muted); margin-bottom: 18px; flex: 1; }
.card-link {
  font-family: var(--font-head);
  font-size: 14px;
  font-weight: 600;
  color: var(--accent-dark);
  display: inline-flex; align-items: center; gap: 6px;
}
.card-link:hover { color: var(--blue); }

/* ---------- Feature / Why us ---------- */
.feature-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 28px; }
.feature-card {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 32px 28px;
}
.feature-icon {
  width: 52px; height: 52px;
  border-radius: 12px;
  background: var(--bg-tint);
  display: grid; place-items: center;
  margin-bottom: 20px;
  color: var(--accent-dark);
}
.feature-icon svg { width: 26px; height: 26px; }
.feature-card h3 { font-size: 19px; margin-bottom: 11px; }
.feature-card p { font-size: 14.5px; color: var(--muted); }

/* ---------- Stats band ---------- */
.stats-band { display: grid; grid-template-columns: repeat(4, 1fr); gap: 24px; text-align: center; }
.stat .num { font-family: var(--font-head); font-size: 42px; font-weight: 700; color: var(--accent); }
.stat .lbl { font-size: 15px; color: #b9ccdf; margin-top: 6px; }

/* ---------- Split / About ---------- */
.split { display: grid; grid-template-columns: 1fr 1fr; gap: 60px; align-items: center; }
.split-media { border-radius: 18px; overflow: hidden; box-shadow: var(--shadow); }
.split-media img { width: 100%; height: 440px; object-fit: cover; }
.check-list { margin-top: 26px; display: grid; gap: 16px; }
.check-list li { display: flex; gap: 14px; align-items: flex-start; font-size: 15.5px; color: var(--ink); }
.check-list .tick {
  flex: 0 0 26px;
  width: 26px; height: 26px;
  border-radius: 50%;
  background: var(--bg-tint);
  color: var(--accent-dark);
  display: grid; place-items: center;
  margin-top: 2px;
}
.check-list .tick svg { width: 14px; height: 14px; }

/* ---------- CTA band ---------- */
.cta-band {
  background: linear-gradient(120deg, var(--blue-2), var(--navy));
  border-radius: 22px;
  padding: 60px 64px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 40px;
  position: relative;
  overflow: hidden;
}
.cta-band::before {
  content: "";
  position: absolute; inset: 0;
  background: radial-gradient(500px 300px at 90% 0, rgba(0,180,216,.25), transparent 60%);
}
.cta-band > * { position: relative; }
.cta-band h2 { color: #fff; font-size: clamp(26px, 3vw, 34px); margin-bottom: 12px; }
.cta-band p { color: #b9ccdf; font-size: 16.5px; }

/* ---------- Footer ---------- */
.site-footer { background: var(--navy); color: #9fb4ca; padding: 72px 0 0; }
.footer-grid { display: grid; grid-template-columns: 1.6fr 1fr 1fr 1.2fr; gap: 44px; padding-bottom: 52px; }
.footer-brand .brand-text strong { color: #fff; }
.footer-brand p { font-size: 14.5px; margin: 20px 0; max-width: 320px; }
.footer-col h4 { color: #fff; font-size: 15px; margin-bottom: 20px; letter-spacing: .03em; }
.footer-col ul { display: grid; gap: 12px; }
.footer-col a { font-size: 14.5px; color: #9fb4ca; }
.footer-col a:hover { color: var(--accent); }
.footer-contact li { display: flex; gap: 12px; font-size: 14.5px; margin-bottom: 14px; align-items: flex-start; }
.footer-contact svg { width: 18px; height: 18px; flex: 0 0 18px; color: var(--accent); margin-top: 3px; }
.footer-bottom {
  border-top: 1px solid rgba(255,255,255,.09);
  padding: 24px 0;
  display: flex; justify-content: space-between; flex-wrap: wrap; gap: 12px;
  font-size: 13.5px; color: #7790a8;
}
.social-row { display: flex; gap: 12px; }
.social-row a {
  width: 38px; height: 38px; border-radius: 50%;
  background: rgba(255,255,255,.07);
  display: grid; place-items: center;
  transition: background .2s;
}
.social-row a:hover { background: var(--accent); color: #04222e; }
.social-row svg { width: 18px; height: 18px; }

/* ---------- WhatsApp float ---------- */
.wa-float {
  position: fixed;
  right: 24px; bottom: 24px;
  z-index: 90;
  width: 58px; height: 58px;
  border-radius: 50%;
  background: var(--wa);
  display: grid; place-items: center;
  box-shadow: 0 10px 28px rgba(37,211,102,.45);
  animation: waPulse 2.4s infinite;
}
.wa-float svg { width: 30px; height: 30px; color: #fff; }
@keyframes waPulse {
  0% { box-shadow: 0 10px 28px rgba(37,211,102,.45), 0 0 0 0 rgba(37,211,102,.5); }
  70% { box-shadow: 0 10px 28px rgba(37,211,102,.45), 0 0 0 16px rgba(37,211,102,0); }
  100% { box-shadow: 0 10px 28px rgba(37,211,102,.45), 0 0 0 0 rgba(37,211,102,0); }
}

/* ---------- Page hero (inner pages) ---------- */
.page-hero {
  background: var(--navy);
  color: #c6d6e8;
  padding: 76px 0 68px;
  position: relative;
  overflow: hidden;
}
.page-hero::before {
  content: "";
  position: absolute; inset: 0;
  background: radial-gradient(700px 320px at 80% 0, rgba(0,180,216,.2), transparent 60%);
}
.page-hero .container { position: relative; }
.breadcrumb { font-size: 14px; color: #88a2bd; margin-bottom: 18px; }
.breadcrumb a:hover { color: var(--accent); }
.breadcrumb .sep { margin: 0 10px; opacity: .6; }
.page-hero h1 { color: #fff; font-size: clamp(32px, 4.2vw, 46px); margin-bottom: 16px; }
.page-hero p { max-width: 680px; font-size: 17px; color: #b9ccdf; }

/* ---------- Product detail ---------- */
.pd-grid { display: grid; grid-template-columns: 1.1fr .9fr; gap: 56px; align-items: start; }
.pd-media { border-radius: 16px; overflow: hidden; box-shadow: var(--shadow); }
.pd-media img { width: 100%; aspect-ratio: 1/1; object-fit: cover; }
.pd-body h2 { font-size: 28px; margin-bottom: 16px; }
.pd-body > p { margin-bottom: 26px; }
.spec-table { width: 100%; border-collapse: collapse; margin: 8px 0 28px; }
.spec-table th, .spec-table td {
  text-align: left;
  padding: 13px 16px;
  font-size: 14.5px;
  border-bottom: 1px solid var(--line);
}
.spec-table th { background: var(--bg-soft); color: var(--ink); font-weight: 600; width: 38%; }
.pd-actions { display: flex; gap: 14px; flex-wrap: wrap; }

/* ---------- Product category list ---------- */
.cat-list { display: grid; grid-template-columns: repeat(2, 1fr); gap: 22px; }
.cat-item {
  display: flex; gap: 18px;
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  padding: 22px;
  align-items: flex-start;
}
.cat-item:hover { border-color: #cfe0f0; box-shadow: var(--shadow); }
.cat-item .dot {
  flex: 0 0 40px; width: 40px; height: 40px;
  border-radius: 10px;
  background: var(--bg-tint);
  color: var(--accent-dark);
  display: grid; place-items: center;
  font-family: var(--font-head); font-weight: 700;
}
.cat-item h4 { font-size: 17px; margin-bottom: 5px; }
.cat-item p { font-size: 14px; color: var(--muted); }

/* ---------- Forms ---------- */
.form-card {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 40px;
  box-shadow: var(--shadow);
}
.form-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 20px; }
.form-field { display: flex; flex-direction: column; gap: 8px; }
.form-field.full { grid-column: 1 / -1; }
.form-field label { font-size: 14px; font-weight: 600; color: var(--ink); }
.form-field input, .form-field select, .form-field textarea {
  font-family: var(--font-body);
  font-size: 15px;
  padding: 13px 16px;
  border: 1.5px solid var(--line);
  border-radius: var(--radius-sm);
  background: #fbfdff;
  color: var(--ink);
  transition: border-color .15s;
}
.form-field input:focus, .form-field select:focus, .form-field textarea:focus {
  outline: none; border-color: var(--accent); background: #fff;
}
.form-field textarea { resize: vertical; min-height: 130px; }
.form-note { font-size: 13.5px; color: var(--muted); margin-top: 14px; }

.contact-cards { display: grid; gap: 22px; }
.contact-info-card {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 26px 28px;
  display: flex; gap: 18px; align-items: flex-start;
}
.contact-info-card .ci {
  flex: 0 0 48px; width: 48px; height: 48px;
  border-radius: 12px;
  background: var(--bg-tint);
  color: var(--accent-dark);
  display: grid; place-items: center;
}
.contact-info-card .ci svg { width: 24px; height: 24px; }
.contact-info-card h4 { font-size: 17px; margin-bottom: 5px; }
.contact-info-card p, .contact-info-card a { font-size: 15px; color: var(--muted); }
.contact-info-card a:hover { color: var(--accent-dark); }

/* ---------- Values / timeline ---------- */
.value-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 26px; }
.value-card {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 30px 28px;
  background: #fff;
}
.value-card .num {
  font-family: var(--font-head);
  font-size: 15px;
  font-weight: 700;
  color: var(--accent);
  letter-spacing: .12em;
  margin-bottom: 14px;
}
.value-card h3 { font-size: 19px; margin-bottom: 10px; }
.value-card p { font-size: 14.5px; color: var(--muted); }

/* ---------- Responsive ---------- */
@media (max-width: 1024px) {
  .product-grid { grid-template-columns: repeat(2, 1fr); }
  .hero-grid { grid-template-columns: 1fr; gap: 44px; padding: 72px 0 80px; }
  .hero-media img { height: 380px; }
  .footer-grid { grid-template-columns: 1fr 1fr; }
  .feature-grid, .value-grid { grid-template-columns: 1fr 1fr; }
  .stats-band { grid-template-columns: 1fr 1fr; gap: 36px; }
  .pd-grid { grid-template-columns: 1fr; }
}

@media (max-width: 768px) {
  .section { padding: 64px 0; }
  .nav-toggle { display: block; }
  .main-nav {
    position: fixed;
    top: 74px; left: 0; right: 0;
    background: #fff;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: 12px 20px 24px;
    border-bottom: 1px solid var(--line);
    box-shadow: var(--shadow);
    max-height: 0;
    overflow: hidden;
    transition: max-height .3s ease;
  }
  .main-nav.open { max-height: 600px; }
  .main-nav > li > a { padding: 14px 12px; }
  .dropdown { position: static; opacity: 1; visibility: visible; transform: none; box-shadow: none; border: none; padding: 0 0 0 16px; display: none; }
  .has-dropdown.open .dropdown { display: block; }
  .nav-cta { margin: 12px 0 0; }
  .split { grid-template-columns: 1fr; gap: 36px; }
  .split-media img { height: 300px; }
  .cta-band { flex-direction: column; align-items: flex-start; padding: 44px 32px; }
  .form-grid { grid-template-columns: 1fr; }
  .form-card { padding: 28px 22px; }
  .cat-list { grid-template-columns: 1fr; }
  .hero-stats { gap: 28px; }
}

@media (max-width: 520px) {
  .product-grid, .feature-grid, .value-grid { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr; }
  .stats-band { grid-template-columns: 1fr; }
  .hero-actions .btn { flex: 1; }
  .container { padding: 0 18px; }
}