/* ---------- Design tokens ---------- */
:root {
  --color-bg-dark: #14161a;
  --color-bg-dark-2: #1b1e24;
  --color-bg-light: #f7f7f8;
  --color-text-dark-bg: #f3f3f2;
  --color-text-light-bg: #1c1c1c;
  --color-muted-dark-bg: #b9bcc3;
  --color-muted-light-bg: #5c5f66;
  --color-accent: #f5821f;
  --color-accent-hover: #ff9a3d;
  --color-border-dark: rgba(255, 255, 255, 0.12);
  --color-border-light: rgba(0, 0, 0, 0.1);
  --font-main: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Noto Sans SC', Roboto, sans-serif;
  --container-width: 1160px;
  --radius-pill: 999px;
  --radius-card: 14px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: var(--font-main);
  background: var(--color-bg-light);
  color: var(--color-text-light-bg);
  line-height: 1.6;
}
img { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }
h1, h2, h3, h4 { line-height: 1.25; margin: 0 0 0.5em; font-weight: 700; }

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

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 10px 22px;
  font-weight: 600;
  font-size: 0.95rem;
  border: 1px solid currentColor;
  border-radius: 8px;
  cursor: pointer;
  transition: all 0.2s ease;
  background: transparent;
}
.btn--pill { border-radius: var(--radius-pill); }
.btn--cta {
  background: var(--color-accent);
  border-color: var(--color-accent);
  color: #14161a;
}
.btn--cta:hover { background: var(--color-accent-hover); border-color: var(--color-accent-hover); }
.btn--outline {
  border-color: var(--color-accent);
  color: var(--color-accent);
  background: transparent;
}
.btn--outline:hover { background: var(--color-accent); color: #14161a; }
.btn--lg { padding: 14px 32px; font-size: 1.05rem; }
.btn--sm { padding: 6px 16px; font-size: 0.85rem; }

/* ---------- Header ---------- */
.site-header {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 100;
  background: transparent;
  transition: background 0.25s ease, box-shadow 0.25s ease;
  padding: 18px 0;
}
.site-header.is-scrolled {
  background: rgba(20, 22, 26, 0.92);
  backdrop-filter: blur(6px);
  box-shadow: 0 2px 12px rgba(0,0,0,0.2);
  padding: 12px 0;
}
.site-header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}
.logo { display: flex; align-items: center; gap: 8px; }
.logo__img { height: 36px; width: auto; }
.logo__text { font-weight: 800; letter-spacing: 0.04em; color: #fff; font-size: 1.1rem; }
.nav { display: flex; gap: 28px; }
.nav a { color: #fff; font-weight: 500; font-size: 0.95rem; opacity: 0.9; }
.nav a:hover { opacity: 1; color: var(--color-accent); }
.header-actions { display: flex; align-items: center; gap: 16px; }
.lang-switcher { display: flex; gap: 6px; }
.lang-switcher__item {
  color: #fff; opacity: 0.6; font-size: 0.8rem; font-weight: 700; padding: 4px 6px;
}
.lang-switcher__item.is-active, .lang-switcher__item:hover { opacity: 1; color: var(--color-accent); }
.header-actions .btn--cta { color: #14161a; }
.hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px;
}
.hamburger span { width: 24px; height: 2px; background: #fff; display: block; }

/* ---------- Hero ---------- */
.hero {
  position: relative;
  background: var(--color-bg-dark);
  color: var(--color-text-dark-bg);
  padding: 160px 0 100px;
  overflow: hidden;
  min-height: 620px;
  display: flex;
  align-items: center;
}
.hero__blob {
  position: absolute;
  top: -10%; right: -10%;
  width: 75%; height: 120%;
  background-size: cover;
  background-position: center;
  clip-path: path('M 400,20 C 620,-40 800,120 760,340 C 720,560 480,640 260,560 C 40,480 -40,260 60,140 C 130,50 260,60 400,20 Z');
  opacity: 0.55;
}
.hero__content { position: relative; z-index: 2; max-width: 640px; }
.hero__eyebrow {
  color: var(--color-accent);
  text-transform: uppercase;
  letter-spacing: 0.12em;
  font-weight: 700;
  font-size: 0.8rem;
  margin-bottom: 14px;
}
.hero__title { font-size: clamp(2.1rem, 4.5vw, 3.4rem); margin-bottom: 18px; }
.hero__subtitle { color: var(--color-muted-dark-bg); font-size: 1.1rem; margin-bottom: 32px; max-width: 520px; }

/* ---------- Sections ---------- */
.section { padding: 80px 0; }
.section--light { background: var(--color-bg-light); color: var(--color-text-light-bg); }
.section--dark { background: var(--color-bg-dark-2); color: var(--color-text-dark-bg); }
.section__title { font-size: clamp(1.6rem, 3vw, 2.2rem); text-align: center; }
.section__subtitle { text-align: center; max-width: 640px; margin: 0 auto 48px; opacity: 0.75; }
.section__eyebrow {
  text-align: center; text-transform: uppercase; letter-spacing: 0.12em;
  color: var(--color-accent); font-weight: 700; font-size: 0.8rem; margin-bottom: 24px;
}
.page-hero {
  background: var(--color-bg-dark);
  color: #fff;
  padding: 150px 0 60px;
}
.page-hero p { color: var(--color-muted-dark-bg); max-width: 620px; }

/* ---------- Certification badges ---------- */
.cert-strip { display: flex; flex-wrap: wrap; justify-content: center; gap: 20px; }
.cert-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 24px; }
.cert-badge {
  display: flex; align-items: flex-start; gap: 14px;
  background: rgba(255,255,255,0.04);
  border: 1px solid var(--color-border-dark);
  border-radius: var(--radius-card);
  padding: 16px 18px;
  min-width: 220px;
}
.cert-grid .cert-badge { background: #fff; border-color: var(--color-border-light); }
.cert-badge__icon {
  flex: none; width: 42px; height: 42px; border-radius: 50%;
  background: var(--color-accent); color: #14161a; font-weight: 800; font-size: 0.7rem;
  display: flex; align-items: center; justify-content: center; text-align: center;
}
.cert-badge__name { margin: 0; font-weight: 700; font-size: 0.95rem; }
.cert-badge__desc { margin: 4px 0 0; font-size: 0.85rem; opacity: 0.75; }
.cert-disclaimer { text-align: center; margin-top: 32px; font-size: 0.85rem; opacity: 0.6; max-width: 720px; margin-left: auto; margin-right: auto; }

/* ---------- Category cards ---------- */
.category-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); gap: 28px; }
.category-card {
  display: block;
  background: #fff;
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-card);
  padding: 32px 28px;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}
.category-card:hover { transform: translateY(-4px); box-shadow: 0 12px 24px rgba(0,0,0,0.08); }
.category-card__icon { font-size: 2.2rem; margin-bottom: 14px; }
.category-card__title { font-size: 1.2rem; }
.category-card__desc { opacity: 0.75; font-size: 0.92rem; }
.category-card__link { color: var(--color-accent); font-weight: 700; font-size: 0.9rem; }

/* ---------- Why us ---------- */
.why-us__grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 28px; }
.why-us__item h3 { color: var(--color-accent); font-size: 1.05rem; }
.why-us__item p { opacity: 0.8; font-size: 0.92rem; }

/* ---------- CTA band ---------- */
.cta-band__inner { text-align: center; }
.cta-band__inner h2 { margin-bottom: 24px; }

/* ---------- Product grid (products page) ---------- */
.product-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); gap: 24px; }
.product-card {
  border-radius: var(--radius-card);
  padding: 24px;
  background: rgba(127,127,127,0.06);
  border: 1px solid var(--color-border-light);
}
.section--dark .product-card { background: rgba(255,255,255,0.05); border-color: var(--color-border-dark); }
.product-card__name { font-size: 1.05rem; margin-bottom: 6px; }
.product-card__desc { opacity: 0.75; font-size: 0.9rem; margin-bottom: 12px; }
.product-card__standards { display: flex; flex-wrap: wrap; gap: 6px; margin-bottom: 14px; }
.tag {
  display: inline-block; font-size: 0.75rem; padding: 3px 10px;
  border-radius: var(--radius-pill); border: 1px solid var(--color-accent); color: var(--color-accent);
}

/* ---------- About page ---------- */
.about-content { max-width: 760px; margin: 0 auto; }
.about-content p { margin-bottom: 1.2em; }
.about-content h2 { margin-top: 1.6em; }

/* ---------- Contact / form ---------- */
.contact-layout { display: grid; grid-template-columns: 2fr 1fr; gap: 48px; align-items: start; }
.form-fieldset { border: none; padding: 0; margin: 0 0 32px; }
.form-fieldset legend { font-weight: 700; font-size: 1.1rem; margin-bottom: 16px; padding: 0; }
.form-row { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
.form-group { margin-bottom: 16px; }
.form-group label { display: block; font-size: 0.88rem; font-weight: 600; margin-bottom: 6px; }
.form-required { color: #b3261e; font-weight: 800; }
.form-required-text { color: #b3261e; font-size: 0.8rem; font-weight: 600; }
.form-required-note { margin: 0 0 20px; font-size: 0.85rem; opacity: 0.72; }
.form-fast-tip {
  display: flex; gap: 12px; align-items: flex-start;
  background: #fff3e6;
  border-left: 4px solid var(--color-accent);
  border-radius: 10px;
  padding: 14px 16px;
  margin: 0 0 20px;
  font-size: 0.95rem;
  color: #6b3f12;
}
.form-fast-tip p { margin: 0; }
.form-fast-tip strong { color: #b85c00; }
.form-fast-tip__icon { font-size: 1.15rem; line-height: 1.4; }
.form-group input,
.form-group select,
.form-group textarea {
  width: 100%;
  padding: 10px 12px;
  border: 1px solid var(--color-border-light);
  border-radius: 8px;
  font-family: inherit;
  font-size: 0.95rem;
  background: #fff;
}
.form-group input:focus, .form-group select:focus, .form-group textarea:focus {
  outline: none; border-color: var(--color-accent);
}
.form-hint { display: block; margin-top: 6px; font-size: 0.8rem; line-height: 1.45; opacity: 0.68; }
.field-error { margin: 6px 0 0; color: #b3261e; font-size: 0.84rem; line-height: 1.4; }
.field-error[hidden] { display: none; }
.form-group--invalid input,
.form-group--invalid select,
.form-group--invalid textarea { border-color: #b3261e; }
.form-group--invalid input:focus,
.form-group--invalid select:focus,
.form-group--invalid textarea:focus { outline: 2px solid rgba(179,38,30,0.2); }
.form-group--invalid .radio-group { outline: 2px solid rgba(179,38,30,0.2); outline-offset: 4px; }
.captcha-group { margin: 0 0 16px; }
.captcha-group:focus { outline: none; }
.captcha-group.form-group--invalid .cf-turnstile { outline: 2px solid rgba(179,38,30,0.35); outline-offset: 4px; }
.radio-group { display: flex; gap: 20px; }
.radio-label { display: flex; align-items: center; gap: 6px; font-weight: 500; font-size: 0.92rem; }
.form-actions { margin-top: 8px; }
.form-alert {
  padding: 12px 16px; border-radius: 8px; margin-bottom: 20px; font-size: 0.92rem;
}
.form-alert--success { background: #e7f6ec; color: #1c7a3c; }
.form-alert--error { background: #fdecec; color: #b3261e; }
.contact-sidebar {
  background: rgba(127,127,127,0.06);
  border-radius: var(--radius-card);
  padding: 24px;
}
.contact-sidebar h3 { font-size: 1.05rem; }
.contact-sidebar .social-icons { margin-top: 16px; }
.contact-sidebar .social-icons a,
.contact-sidebar .social-icons button {
  color: #1565c0; font-weight: 600; text-decoration: underline; text-underline-offset: 3px;
}
.contact-sidebar .social-icons a:hover,
.contact-sidebar .social-icons button:hover { color: #0d47a1; }

/* ---------- Footer ---------- */
.site-footer { background: #0f1013; color: #d7d8db; padding: 60px 0 0; }
.footer__grid { display: grid; grid-template-columns: 2fr 1fr 1fr; gap: 40px; padding-bottom: 40px; }
.footer__col h4 { color: #fff; font-size: 0.95rem; margin-bottom: 14px; }
.footer__col a { display: block; margin-bottom: 8px; font-size: 0.9rem; opacity: 0.8; }
.footer__col a:hover { opacity: 1; color: var(--color-accent); }
.footer__company-name { color: #fff; font-weight: 700; margin: 12px 0 4px; }
.footer__muted { font-size: 0.85rem; opacity: 0.65; margin: 2px 0; }
.footer__bottom {
  border-top: 1px solid rgba(255,255,255,0.08);
  padding: 18px 0;
  font-size: 0.8rem;
  opacity: 0.6;
  text-align: center;
}
.social-icons { display: flex; flex-wrap: wrap; gap: 10px; }
.social-icons__item {
  display: inline-flex; align-items: center; padding: 6px 14px; border-radius: var(--radius-pill);
  border: 1px solid rgba(255,255,255,0.2); font-size: 0.8rem; font-weight: 600; cursor: pointer; background: transparent; color: inherit;
}
.social-icons__item:hover { border-color: var(--color-accent); color: var(--color-accent); }

/* ---------- Floating social buttons ---------- */
.floating-social {
  position: fixed; right: 20px; bottom: 24px; z-index: 90;
  display: flex; flex-direction: column; gap: 10px;
}
.floating-social__btn {
  width: 52px; height: 52px; border-radius: 50%;
  display: flex; align-items: center; justify-content: center;
  color: #fff; font-weight: 800; box-shadow: 0 6px 16px rgba(0,0,0,0.25);
}
.floating-social__btn--whatsapp { background: #25D366; }
.floating-social__btn--zalo { background: #0068FF; }

/* ---------- WeChat modal ---------- */
.wechat-modal { position: fixed; inset: 0; z-index: 200; display: flex; align-items: center; justify-content: center; }
.wechat-modal[hidden] { display: none; }
.wechat-modal__backdrop { position: absolute; inset: 0; background: rgba(0,0,0,0.6); }
.wechat-modal__content {
  position: relative; background: #fff; border-radius: 14px; padding: 32px; text-align: center; max-width: 300px;
}
.wechat-modal__close {
  position: absolute; top: 8px; right: 12px; border: none; background: none; font-size: 1.4rem; cursor: pointer;
}
.wechat-modal__qr { width: 100%; margin-bottom: 12px; }

/* ---------- Responsive ---------- */
@media (max-width: 900px) {
  .contact-layout { grid-template-columns: 1fr; }
  .footer__grid { grid-template-columns: 1fr; }
}
@media (max-width: 780px) {
  .nav { position: fixed; top: 0; right: -100%; height: 100vh; width: 260px; background: var(--color-bg-dark); flex-direction: column; padding: 100px 32px; gap: 20px; transition: right 0.25s ease; }
  .nav.is-open { right: 0; }
  .hamburger { display: flex; }
  .lang-switcher { order: 2; }
  .form-row { grid-template-columns: 1fr; }
  .hero { padding-top: 130px; min-height: auto; }
}