:root {
  --navy: #1f2d3d;
  --orange: #F5921F;
  --text: #55636f;
  --bg-soft: #f5f8fb;
  --border: #e3e8ee;
  --white: #ffffff;
  --maxw: 1100px;
}

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

html { scroll-behavior: smooth; }

body {
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  color: var(--navy);
  background: var(--white);
  line-height: 1.6;
}

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

a { color: inherit; text-decoration: none; }

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

/* ===== Header ===== */
.site-header {
  position: sticky; top: 0; z-index: 50;
  background: var(--white);
  border-bottom: 1px solid var(--border);
}
.header-inner {
  display: flex; align-items: center; justify-content: space-between;
  height: 84px;
}
.brand { display: flex; align-items: center; gap: 12px; }
.brand-logo { height: 68px; width: auto; }
.brand-name { font-weight: 800; letter-spacing: .5px; color: var(--navy); }
.nav { display: flex; gap: 22px; }
.nav a { color: var(--text); font-weight: 600; font-size: 15px; }
.nav a:hover { color: var(--orange); }

/* ===== Hero ===== */
.hero { background: var(--bg-soft); padding: 64px 0; }
.hero-inner { display: flex; align-items: center; gap: 44px; }
.hero-text { flex: 1; }
.hero-logo { width: 300px; max-width: 38%; height: auto; flex-shrink: 0; }
.eyebrow { color: var(--orange); font-weight: 700; letter-spacing: 1px; font-size: 14px; }
.hero-title { font-size: 40px; font-weight: 800; color: var(--navy); margin: 10px 0 14px; line-height: 1.2; }
.hero-sub { font-size: 18px; color: var(--text); max-width: 640px; margin-bottom: 26px; }
.hero-cta { display: flex; gap: 12px; flex-wrap: wrap; }

.btn { display: inline-block; padding: 13px 22px; border-radius: 8px; font-weight: 700; font-size: 16px; }
.btn-primary { background: var(--orange); color: var(--white); }
.btn-primary:hover { filter: brightness(.95); }
.btn-outline { border: 1.5px solid var(--navy); color: var(--navy); }
.btn-outline:hover { background: var(--navy); color: var(--white); }

/* ===== Sections ===== */
.section { padding: 56px 0; }
.section-alt { background: var(--bg-soft); }
.section-title { font-size: 28px; font-weight: 800; color: var(--navy); text-align: center; margin-bottom: 32px; }

/* ===== Vì sao ===== */
.feature-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 18px; }
.feature-card { background: var(--bg-soft); border-radius: 12px; padding: 26px 22px; }
.feature-icon { font-size: 32px; margin-bottom: 10px; }
.feature-card h3 { color: var(--navy); font-size: 18px; margin-bottom: 6px; }
.feature-card p { color: var(--text); font-size: 15px; }

/* ===== Dịch vụ & giá ===== */
.price-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 20px; }
.price-card { background: var(--white); border: 1px solid var(--border); border-radius: 12px; padding: 28px; }
.price-card h3 { color: var(--navy); font-size: 20px; margin-bottom: 10px; }
.price-desc { color: var(--text); font-size: 15px; margin-bottom: 16px; }
.price-value { color: var(--orange); font-weight: 800; font-size: 22px; }
.price-note { color: var(--text); font-size: 13px; text-align: center; margin-top: 18px; font-style: italic; }

/* ===== Sản phẩm ===== */
.product-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 16px; }
.product-card { background: var(--white); border: 1px solid var(--border); border-radius: 12px; overflow: hidden; }
.product-card img { width: 100%; height: 180px; object-fit: cover; }
.product-card figcaption { padding: 12px; text-align: center; font-weight: 600; color: var(--navy); font-size: 15px; }

/* ===== Công trình ===== */
.gallery-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; }
.gallery-card { background: var(--white); border: 1px solid var(--border); border-radius: 12px; overflow: hidden; }
.gallery-card img { width: 100%; height: 240px; object-fit: cover; }
.gallery-card figcaption { padding: 12px; text-align: center; color: var(--text); font-size: 14px; }

/* ===== Footer ===== */
.footer { background: var(--navy); color: #c4d0dc; padding: 48px 0 0; }
.footer-inner { display: grid; grid-template-columns: 1.2fr 1fr 1fr; gap: 28px; }
.footer-logo { height: 140px; width: auto; }
.footer-slogan { color: var(--orange); font-weight: 600; margin-top: 6px; }
.footer-col h4 { color: var(--white); margin-bottom: 12px; font-size: 16px; }
.footer-col p { margin-bottom: 8px; font-size: 15px; }
.footer-col a:hover { color: var(--orange); }
.footer-bottom { text-align: center; padding: 20px; margin-top: 32px; border-top: 1px solid #ffffff22; font-size: 14px; }

/* ===== Nút nổi ===== */
.float-btn {
  position: fixed; right: 18px; z-index: 60;
  width: 52px; height: 52px; border-radius: 50%;
  display: flex; align-items: center; justify-content: center;
  font-size: 24px; color: var(--white);
  box-shadow: 0 4px 12px rgba(0,0,0,.25);
}
.float-call { bottom: 84px; background: var(--orange); }
.float-zalo { bottom: 22px; background: #0068ff; }

/* ===== Responsive ===== */
@media (max-width: 900px) {
  .product-grid { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 760px) {
  .feature-grid,
  .price-grid,
  .gallery-grid,
  .footer-inner { grid-template-columns: 1fr; }
  .hero { padding: 40px 0; }
  .hero-inner { flex-direction: column-reverse; gap: 24px; text-align: center; }
  .hero-logo { width: 220px; max-width: 70%; }
  .hero-sub { font-size: 16px; margin-left: auto; margin-right: auto; }
  .hero-title { font-size: 28px; }
  .hero-cta { justify-content: center; }
  .btn { width: 100%; text-align: center; }
}
@media (max-width: 640px) {
  .header-inner { height: 70px; }
  .brand-logo { height: 54px; }
  .brand-name { font-size: 14px; }
  .nav { gap: 12px; }
  .nav a { font-size: 13px; }
}
@media (max-width: 480px) {
  .product-grid { grid-template-columns: 1fr; }
}