:root {
  --primary: #1660a8;
  --primary-dark: #0e4478;
  --accent: #f5a623;
  --dark: #14263b;
  --gray: #5a6b7d;
  --light: #f4f7fa;
  --white: #fff;
  --radius: 8px;
  --shadow: 0 4px 18px rgba(20, 38, 59, .10);
  --maxw: 1200px;
}

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

html { scroll-behavior: smooth; }

body {
  font-family: "Segoe UI", "Helvetica Neue", Arial, "PingFang SC", sans-serif;
  color: var(--dark);
  line-height: 1.65;
  background: var(--white);
}

img { max-width: 100%; height: auto; display: block; }

a { color: var(--primary); text-decoration: none; }
a:hover { color: var(--primary-dark); }

.container { max-width: var(--maxw); margin: 0 auto; padding: 0 20px; }

/* ============ Header ============ */
.site-header {
  position: sticky; top: 0; z-index: 100;
  background: var(--white);
  box-shadow: 0 2px 10px rgba(0, 0, 0, .08);
}
.header-inner {
  max-width: var(--maxw); margin: 0 auto; padding: 10px 20px;
  display: flex; align-items: center; justify-content: space-between; gap: 16px;
}
.brand { display: flex; align-items: center; gap: 10px; }
.brand img { height: 44px; width: auto; }
.brand .brand-name { font-size: 1.05rem; font-weight: 700; color: var(--dark); line-height: 1.2; }
.brand .brand-name span { display: block; font-size: .72rem; font-weight: 500; color: var(--gray); }

.main-nav ul { list-style: none; display: flex; gap: 6px; }
.main-nav a {
  display: block; padding: 10px 16px; font-weight: 600; font-size: .95rem;
  color: var(--dark); border-radius: 6px;
}
.main-nav a:hover, .main-nav a.active { background: var(--light); color: var(--primary); }
.nav-toggle {
  display: none; background: none; border: 0; cursor: pointer; padding: 8px;
}
.nav-toggle span, .nav-toggle span::before, .nav-toggle span::after {
  display: block; width: 26px; height: 3px; background: var(--dark); border-radius: 2px;
  position: relative; content: "";
}
.nav-toggle span::before { position: absolute; top: -8px; }
.nav-toggle span::after { position: absolute; top: 8px; }

/* ============ Hero ============ */
.hero {
  position: relative; min-height: 460px;
  display: flex; align-items: center;
  background: linear-gradient(rgba(10, 30, 55, .62), rgba(10, 30, 55, .62)), url("/img/banner.jpg") center / cover no-repeat;
  color: var(--white); text-align: center;
}
.hero-inner { max-width: 860px; margin: 0 auto; padding: 90px 20px; }
.hero h1 { font-size: clamp(1.8rem, 4.5vw, 3.2rem); line-height: 1.2; margin-bottom: 18px; }
.hero p { font-size: clamp(1rem, 2vw, 1.25rem); color: #dfe8f2; margin-bottom: 32px; }

.btn {
  display: inline-block; padding: 13px 34px; border-radius: 6px;
  font-weight: 700; font-size: 1rem; transition: all .2s; border: 2px solid transparent;
}
.btn-primary { background: var(--accent); color: #1e1e1e; }
.btn-primary:hover { background: #e09212; color: #1e1e1e; }
.btn-outline { border-color: var(--white); color: var(--white); }
.btn-outline:hover { background: var(--white); color: var(--primary-dark); }
.btn-dark { background: var(--primary); color: var(--white); }
.btn-dark:hover { background: var(--primary-dark); color: var(--white); }

/* ============ Page banner (subpages) ============ */
.page-banner {
  background: linear-gradient(rgba(14, 55, 100, .85), rgba(14, 55, 100, .85)), url("/img/banner.jpg") center / cover no-repeat;
  color: var(--white); text-align: center; padding: 70px 20px 60px;
}
.page-banner h1 { font-size: clamp(1.6rem, 3.5vw, 2.4rem); margin-bottom: 10px; }
.breadcrumb { font-size: .9rem; color: #c8d6e5; }
.breadcrumb a { color: #c8d6e5; }
.breadcrumb a:hover { color: var(--white); }

/* ============ Sections ============ */
.section { padding: 70px 0; }
.section.alt { background: var(--light); }
.section-head { text-align: center; max-width: 760px; margin: 0 auto 46px; }
.section-head h2 {
  font-size: clamp(1.5rem, 3vw, 2.1rem); margin-bottom: 12px; position: relative; padding-bottom: 14px;
}
.section-head h2::after {
  content: ""; display: block; width: 56px; height: 4px; border-radius: 2px;
  background: var(--accent); margin: 12px auto 0;
}
.section-head p { color: var(--gray); }

.grid { display: grid; gap: 26px; }
.grid-2 { grid-template-columns: repeat(2, 1fr); }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-4 { grid-template-columns: repeat(4, 1fr); }

.grid-5 { grid-template-columns: repeat(5, 1fr); }

/* ============ Cards ============ */
.card {
  background: var(--white); border-radius: var(--radius); overflow: hidden;
  box-shadow: var(--shadow); transition: transform .2s, box-shadow .2s;
  display: flex; flex-direction: column;
}
.card:hover { transform: translateY(-5px); box-shadow: 0 10px 26px rgba(20, 38, 59, .16); }
.card img { width: 100%; aspect-ratio: 3 / 2; object-fit: cover; }
.card-body { padding: 20px; flex: 1; display: flex; flex-direction: column; }
.card-body h3 { font-size: 1.08rem; margin-bottom: 8px; }
.card-body p { color: var(--gray); font-size: .92rem; margin-bottom: 14px; }
.card-body .more { margin-top: auto; font-weight: 700; color: var(--primary); }

.icon-card { text-align: center; padding: 34px 22px; background: var(--white); border-radius: var(--radius); box-shadow: var(--shadow); }
.icon-card .num { font-size: 2rem; font-weight: 800; color: var(--primary); }
.icon-card h3 { margin: 8px 0 6px; font-size: 1.5rem; }
.icon-card p { color: var(--gray); font-size: .95rem; }

/* ============ Split (about) ============ */
.split { display: grid; grid-template-columns: 1fr 1fr; gap: 44px; align-items: center; }
.split img { border-radius: var(--radius); box-shadow: var(--shadow); }
.split h2 { font-size: clamp(1.4rem, 3vw, 2rem); margin-bottom: 16px; }
.split p { color: var(--gray); margin-bottom: 14px; }
.check-list { list-style: none; margin: 12px 0 20px; }
.check-list li { padding-left: 30px; position: relative; margin-bottom: 10px; color: var(--dark); }
.check-list li::before {
  content: "✔"; position: absolute; left: 0; top: 0; color: var(--accent); font-weight: 800;
}

/* ============ Product detail ============ */
.product-detail { display: grid; grid-template-columns: minmax(0, 5fr) minmax(0, 6fr); gap: 40px; align-items: start; }
.product-detail .product-img {
  background: var(--white); border-radius: var(--radius); box-shadow: var(--shadow); overflow: hidden;
  position: sticky; top: 90px;
}
.product-detail .product-img img { width: 100%; aspect-ratio: 3 / 2; object-fit: cover; }
.product-detail h1 { font-size: clamp(1.4rem, 3vw, 2rem); margin-bottom: 14px; }
.product-detail .lead { color: var(--gray); font-size: 1.05rem; margin-bottom: 22px; }
.spec-table { width: 100%; border-collapse: collapse; margin: 10px 0 24px; font-size: .94rem; }
.spec-table th, .spec-table td { border: 1px solid #dde5ee; padding: 10px 14px; text-align: left; }
.spec-table th { background: var(--light); width: 34%; }
.detail-block { margin-top: 36px; }
.detail-block h2 { font-size: 1.35rem; margin-bottom: 12px; padding-left: 14px; border-left: 4px solid var(--accent); }
.detail-block p { color: var(--gray); margin-bottom: 12px; }
.detail-block ul { margin: 0 0 12px 20px; color: var(--gray); }
.detail-block li { margin-bottom: 8px; }

/* ============ CTA band ============ */
.cta-band {
  background: linear-gradient(120deg, var(--primary-dark), var(--primary));
  color: var(--white); text-align: center; padding: 58px 20px;
}
.cta-band h2 { font-size: clamp(1.4rem, 3vw, 2rem); margin-bottom: 10px; }
.cta-band p { color: #d6e2ef; margin-bottom: 26px; max-width: 640px; margin-left: auto; margin-right: auto; }

/* ============ Contact ============ */
.contact-wrap { display: grid; grid-template-columns: 2fr 1fr; gap: 40px; align-items: start; }
.contact-info-card { background: var(--light); border-radius: var(--radius); padding: 30px; }
.contact-info-card h3 { margin-bottom: 14px; }
.contact-info-card p { color: var(--gray); margin-bottom: 12px; font-size: .95rem; }

.form-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 18px; }
.form-field { display: flex; flex-direction: column; }
.form-field.full { grid-column: 1 / -1; }
.form-field label { font-weight: 600; font-size: .9rem; margin-bottom: 6px; }
.form-field label .req { color: #d43f3a; }
.form-field input, .form-field textarea, .form-field select {
  padding: 12px 14px; border: 1px solid #ccd6e0; border-radius: 6px;
  font-size: .95rem; font-family: inherit; background: var(--white);
}
.form-field input:focus, .form-field textarea:focus, .form-field select:focus {
  outline: none; border-color: var(--primary); box-shadow: 0 0 0 3px rgba(22, 96, 168, .14);
}
.form-note { font-size: .85rem; color: var(--gray); margin-top: 10px; }

.form-msg { display: none; padding: 14px 18px; border-radius: 6px; margin-bottom: 18px; font-weight: 600; }
.form-msg.ok { display: block; background: #e6f6ec; color: #1e7a46; border: 1px solid #bce4cc; }
.form-msg.err { display: block; background: #fdecec; color: #b02a2a; border: 1px solid #f3c1c1; }

/* ============ Footer ============ */
.site-footer { background: var(--dark); color: #b8c4d2; padding: 56px 0 0; font-size: .94rem; }
.footer-grid { display: grid; grid-template-columns: 1.4fr 1fr 1fr; gap: 40px; padding-bottom: 40px; }
.site-footer h3 { color: var(--white); font-size: 1.05rem; margin-bottom: 16px; }
.site-footer ul { list-style: none; }
.site-footer li { margin-bottom: 9px; }
.site-footer a { color: #b8c4d2; }
.site-footer a:hover { color: var(--white); }
.footer-bottom {
  border-top: 1px solid rgba(255, 255, 255, .12); padding: 18px 0;
  text-align: center; font-size: .85rem; color: #8fa0b3;
}

/* ============ Responsive ============ */
@media (max-width: 960px) {
  .grid-3, .grid-4 { grid-template-columns: repeat(2, 1fr); }
  .split { grid-template-columns: 1fr; }
  .product-detail { grid-template-columns: 1fr; }
  .product-detail .product-img { position: static; }
  .contact-wrap { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 720px) {
  .nav-toggle { display: block; }
  .main-nav {
    position: absolute; top: 100%; left: 0; right: 0;
    background: var(--white); box-shadow: 0 8px 16px rgba(0, 0, 0, .12);
    display: none;
  }
  .main-nav.open { display: block; }
  .main-nav ul { flex-direction: column; padding: 10px 16px 16px; }
  .main-nav a { padding: 12px 8px; border-bottom: 1px solid #eef2f6; }
  .grid-2, .grid-3, .grid-4 { grid-template-columns: 1fr; }
  .grid-5 { grid-template-columns: repeat(2, 1fr); }
  .form-grid { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr; }
  .section { padding: 52px 0; }
  .hero { min-height: 380px; }
}