/* Nam Hà: thảm xi măng, thùng chống đâm, dải phân cách nhựa */

:root {
  --paper: #ecebe6;
  --paper-2: #e2e0d8;
  --paper-3: #d6d3c9;
  --ink: #17191b;
  --ink-2: #44484c;
  --ink-3: #61666b;
  --line: #c5c1b6;
  --accent: #c2410c;
  --accent-hover: #a3360a;
  --on-accent: #ffffff;
  --night: #1d2124;
  --night-2: #272c30;
  --night-line: #3a4045;
  --on-night: #ecebe6;
  --on-night-2: #b4b8b9;
  --soil: #b89a74;
  --water: #3d7891;
  --concrete: #9c9a92;
  --hazard: #f2c230;
  --barrier-orange: #d9480f;
  --barrier-white: #f1efe9;

  --font: "Be Vietnam Pro", system-ui, sans-serif;
  --mono: "JetBrains Mono", ui-monospace, monospace;
  --wrap: 1240px;
  --gutter: clamp(16px, 4vw, 40px);
  --radius: 12px;
  --ease: cubic-bezier(.16, 1, .3, 1);
}

*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 84px; }
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } }

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font: 400 17px/1.6 var(--font);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}
::selection { background: var(--accent); color: var(--on-accent); }
html { scrollbar-color: var(--ink-3) var(--paper-2); }

h1, h2, h3, h4 { margin: 0; line-height: 1.12; text-wrap: balance; letter-spacing: -0.02em; }
p { margin: 0; text-wrap: pretty; }
a { color: inherit; text-underline-offset: .2em; text-decoration-thickness: 1px; }
a:hover { text-decoration-color: var(--accent); }
:focus-visible { outline: 2px solid var(--accent); outline-offset: 3px; border-radius: 4px; }
svg { display: block; }
.num { font-family: var(--mono); font-variant-numeric: tabular-nums; letter-spacing: 0; }

.wrap { max-width: var(--wrap); margin: 0 auto; padding: 0 var(--gutter); }
.sr-only { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; }
.hp { position: absolute; left: -9999px; width: 1px; height: 1px; opacity: 0; }
.skip { position: absolute; left: 16px; top: -60px; z-index: 100; background: var(--ink); color: var(--paper); padding: 10px 16px; border-radius: 8px; }
.skip:focus { top: 12px; }

/* Buttons */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: .5em;
  min-height: 44px; padding: 0 20px; border-radius: 999px; border: 1px solid transparent;
  font: 600 15px/1 var(--font); text-decoration: none; cursor: pointer;
  transition: background-color .2s var(--ease), color .2s var(--ease), border-color .2s var(--ease);
}
.btn-accent { background: var(--accent); color: var(--on-accent); }
.btn-accent:hover { background: var(--accent-hover); }
.btn-ghost { background: transparent; color: var(--ink); border-color: var(--ink); }
.btn-ghost:hover { background: var(--ink); color: var(--paper); }
.btn[disabled] { opacity: .55; cursor: not-allowed; }

.link-arrow { display: inline-flex; align-items: center; gap: .45em; font-weight: 600; text-decoration: none; border-bottom: 1px solid currentColor; padding-bottom: 2px; }
.link-arrow::after { content: ""; width: .7em; height: .7em; background: currentColor; clip-path: polygon(0 40%, 60% 40%, 60% 10%, 100% 50%, 60% 90%, 60% 60%, 0 60%); transition: transform .25s var(--ease); }
.link-arrow:hover::after { transform: translateX(4px); }
.link-arrow:hover { color: var(--accent); }

/* Header */
.site-header {
  position: sticky; top: 0; z-index: 50;
  background: var(--paper);
  border-bottom: 1px solid var(--line);
}
.header-row { display: flex; align-items: center; justify-content: space-between; min-height: 68px; gap: 24px; }
.brand { display: flex; align-items: center; gap: 10px; text-decoration: none; }
.brand-mark { width: 30px; height: 30px; color: var(--accent); }
.brand-name { font-weight: 800; font-size: 20px; letter-spacing: -0.02em; }
.brand-sub { font-size: 13px; color: var(--ink-3); padding-left: 10px; border-left: 1px solid var(--line); }

.site-nav > ul { display: flex; align-items: center; gap: 4px; list-style: none; margin: 0; padding: 0; }
.site-nav a, .sub-toggle {
  display: inline-flex; align-items: center; gap: 6px; min-height: 44px; padding: 0 14px;
  font: 500 15px/1 var(--font); color: var(--ink); text-decoration: none;
  background: none; border: 0; border-radius: 999px; cursor: pointer;
}
.site-nav > ul > li > a:not(.btn):hover, .sub-toggle:hover { background: var(--paper-2); }
.sub-toggle svg { width: 12px; height: 12px; transition: transform .2s var(--ease); }
.sub-toggle[aria-expanded="true"] svg { transform: rotate(180deg); }
.nav-cta { margin-left: 8px; }
.site-nav .btn-accent { color: var(--on-accent); background: var(--accent); padding: 0 20px; font-weight: 600; }
.site-nav .btn-accent:hover { background: var(--accent-hover); }
.has-sub { position: relative; }
.sub {
  position: absolute; top: calc(100% + 8px); left: 0; min-width: 300px;
  list-style: none; margin: 0; padding: 8px;
  background: var(--paper); border-radius: var(--radius);
  box-shadow: 0 12px 32px -8px rgb(23 25 27 / .25), 0 2px 6px rgb(23 25 27 / .08);
  opacity: 0; visibility: hidden; transform: translateY(-6px);
  transition: opacity .2s var(--ease), transform .2s var(--ease), visibility 0s .2s;
}
.has-sub.is-open .sub { opacity: 1; visibility: visible; transform: none; transition-delay: 0s; }
.sub a { display: grid; gap: 2px; padding: 12px 14px; border-radius: 8px; min-height: 0; line-height: 1.3; }
.sub a:hover { background: var(--paper-2); }
.sub strong { font-weight: 600; }
.sub span { font-size: 13px; color: var(--ink-3); }

.nav-toggle { display: none; width: 44px; height: 44px; border: 0; background: none; color: var(--ink); cursor: pointer; border-radius: 8px; }
.nav-toggle svg { width: 24px; height: 24px; margin: auto; }

/* Hero */
.hero { padding: clamp(48px, 8vw, 96px) 0 clamp(40px, 6vw, 72px); }
.hero-head { display: grid; grid-template-columns: minmax(0, 1.5fr) minmax(0, 1fr); gap: 40px 64px; align-items: end; margin-bottom: clamp(32px, 5vw, 56px); }
.hero h1 { font-size: clamp(2.4rem, 5.4vw, 4.6rem); font-weight: 800; letter-spacing: -0.03em; line-height: 1.04; }
.lede { font-size: clamp(1.05rem, 1.4vw, 1.2rem); color: var(--ink-2); max-width: 44ch; }

.carousel { background: var(--paper-2); border-radius: var(--radius); overflow: hidden; }
.slide { display: grid; grid-template-columns: minmax(0, 1.7fr) minmax(0, 1fr); min-height: 440px; }
.slide:not(.is-active), .slide[hidden] { display: none; }
.slide.is-active { animation: slide-in .6s var(--ease); }
@keyframes slide-in { from { opacity: 0; filter: blur(6px); } to { opacity: 1; filter: none; } }
@media (prefers-reduced-motion: reduce) { .slide.is-active { animation: none; } }
.slide-fig { margin: 0; background: var(--paper-3); position: relative; }
.slide-fig img, .slide-fig svg { position: absolute; inset: 0; width: 100%; height: 100%; object-fit: cover; }
.sym-defs { position: absolute; width: 0; height: 0; overflow: hidden; }

.slide-copy { padding: clamp(24px, 3.5vw, 48px); display: flex; flex-direction: column; justify-content: flex-end; gap: 16px; }
.slide-copy h2 { font-size: clamp(1.6rem, 2.4vw, 2.2rem); font-weight: 700; }
.slide-copy p { color: var(--ink-2); }
.slide-copy .link-arrow { align-self: flex-start; margin-top: 8px; }

.carousel-bar { display: flex; justify-content: space-between; align-items: center; gap: 16px; padding: 12px; border-top: 1px solid var(--line); }
.tabs { display: flex; gap: 4px; overflow-x: auto; }
.tabs button {
  min-height: 44px; padding: 0 16px; border: 0; border-radius: 999px; background: none;
  font: 500 15px/1 var(--font); color: var(--ink-2); cursor: pointer; white-space: nowrap;
}
.tabs button:hover { color: var(--ink); background: var(--paper); }
.tabs button[aria-selected="true"] { background: var(--ink); color: var(--paper); }
.carousel-arrows { display: flex; gap: 8px; }
.icon-btn { width: 44px; height: 44px; border-radius: 999px; border: 1px solid var(--ink); background: none; color: var(--ink); cursor: pointer; display: grid; place-items: center; }
.icon-btn:hover { background: var(--ink); color: var(--paper); }
.icon-btn svg { width: 20px; height: 20px; }

/* Diagrams */
.d-bg { fill: var(--paper-3); }
.d-soil { fill: var(--soil); }
.d-asphalt { fill: var(--night); }
.d-water { fill: var(--water); opacity: .85; }
.d-blanket { fill: none; stroke: var(--concrete); stroke-width: 12; stroke-linejoin: round; }
.ch-fig .d-blanket { stroke: #6b6a64; }
.d-pin path, path.d-pin { stroke: var(--ink); stroke-width: 3; stroke-linecap: round; }
.d-pin { stroke: var(--ink); stroke-width: 3; }
/* Thiết bị giao thông */
.d-shadow { fill: var(--ink); opacity: .14; }
.d-lane { stroke: var(--on-night); stroke-width: 10; stroke-dasharray: 80 60; }
.d-edge { stroke: var(--on-night); stroke-width: 3; fill: none; }
.d-lane-plan { stroke: var(--on-night-2); stroke-width: 3; stroke-dasharray: 24 18; fill: none; }
.d-traffic path { stroke: var(--on-night); stroke-width: 4; fill: none; }
.d-arrowhead { fill: var(--on-night); }
.d-ground { stroke: var(--ink-3); stroke-width: 2; }
.d-leader-mixed { stroke: #8f959a; stroke-width: 1.5; fill: none; }
.d-barrels circle { fill: var(--barrier-orange); stroke: var(--hazard); stroke-width: 4; }
.wb-fill-a { fill: var(--barrier-orange); }
.wb-fill-b { fill: var(--barrier-white); }
.d-pin-fill { fill: #2b2f33; }
.d-water-in { fill: var(--water); opacity: .3; }
.d-water-line { stroke: var(--water); stroke-width: 2; stroke-dasharray: 8 6; }
.wb-a { color: var(--barrier-orange); --strip: var(--barrier-white); }
.wb-b { color: var(--barrier-white); --strip: var(--accent); }
.d-dim path { stroke: var(--ink-3); stroke-width: 1; fill: none; }
.d-leader { stroke: var(--ink); stroke-width: 1; fill: none; }
.d-label text { font: 600 17px var(--font); fill: var(--ink); }
.d-label .d-muted { fill: #3b3022; font-weight: 500; }
.d-label .d-mono { font: 500 14px var(--mono); fill: var(--ink-2); }
.d-label .d-on-water { fill: #fff; font-weight: 500; font-size: 15px; }

/* Intro */
.intro { padding-block: clamp(24px, 4vw, 48px) clamp(56px, 8vw, 96px); }
.intro p { font-size: clamp(1.25rem, 2.1vw, 1.7rem); line-height: 1.45; font-weight: 500; max-width: 46ch; letter-spacing: -0.01em; }
.intro a { text-decoration-color: var(--accent); text-decoration-thickness: 2px; }

/* Section titles */
.section-title { font-size: clamp(1.9rem, 3.6vw, 3rem); font-weight: 700; letter-spacing: -0.025em; }

/* Challenges */
.challenges { padding-bottom: clamp(64px, 9vw, 120px); }
.ch-list { list-style: none; margin: clamp(28px, 4vw, 48px) 0 0; padding: 0; border-top: 2px solid var(--ink); }
.ch-row { display: grid; grid-template-columns: minmax(0, 1.25fr) minmax(0, 1fr); gap: 24px 56px; align-items: center; padding: clamp(28px, 3.5vw, 44px) 0; border-bottom: 1px solid var(--line); }
.ch-fig { margin: 0; border-radius: var(--radius); overflow: hidden; }
.ch-fig svg { width: 100%; height: auto; }
.ch-fig .d-label text { font-size: 21px; }
.ch-fig .d-label .d-mono { font-size: 18px; }
.ch-text { display: grid; gap: 20px; }
.ch-problem h3 { font-size: clamp(1.25rem, 1.8vw, 1.5rem); font-weight: 700; margin-bottom: 10px; }
.ch-problem p { color: var(--ink-2); max-width: 52ch; }
.ch-solution { display: flex; flex-direction: column; gap: 14px; align-items: flex-start; padding-top: 20px; border-top: 1px solid var(--line); }
.ch-solution p { max-width: 50ch; }

/* Product sections */
.product { padding: clamp(72px, 10vw, 128px) 0; }
.product-dark { background: var(--night); color: var(--on-night); }
.product-tint { background: var(--paper-2); }
.product-head { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1fr); gap: 24px 64px; align-items: end; margin-bottom: clamp(40px, 6vw, 72px); }
.product-head h2 { font-size: clamp(2.6rem, 6vw, 5.2rem); font-weight: 800; letter-spacing: -0.035em; line-height: 1; }
.product-sub { font-size: clamp(1.05rem, 1.4vw, 1.2rem); max-width: 48ch; color: var(--ink-2); }
.product-dark .product-sub { color: var(--on-night-2); }
.block-title { font-size: clamp(1.35rem, 2vw, 1.75rem); font-weight: 700; }
.note { font-size: 14px; color: var(--ink-3); max-width: 70ch; }
.product-dark .note { color: var(--on-night-2); }

/* Layers */
.layers { display: grid; grid-template-columns: minmax(0, 1.1fr) minmax(0, 1fr); gap: 40px 64px; align-items: center; }
.layers-fig { margin: 0; }
.layers-fig svg { width: 100%; height: auto; }
.l-top { fill: #d9d4c4; }
.l-core { fill: #8e8b82; }
.l-core-side { fill: #6f6c64; }
.l-base { fill: var(--accent); }
.d-grain { fill: #5c5a53; }
.d-weave { stroke: #a69f8a; stroke-width: 1.2; }
.layers-list { margin: 0; display: grid; gap: 0; }
.layers-list > div { padding: 20px 0; border-top: 1px solid var(--night-line); }
.layers-list > div:last-child { border-bottom: 1px solid var(--night-line); }
.layers-list dt { font-weight: 700; font-size: 1.15rem; margin-bottom: 6px; }
.layers-list dd { margin: 0; color: var(--on-night-2); }

.gallery {
  margin-top: clamp(64px, 8vw, 104px);
  display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); grid-auto-rows: clamp(160px, 17vw, 230px); gap: 12px;
}
.gallery figure { margin: 0; position: relative; border-radius: var(--radius); overflow: hidden; background: var(--night-2); }
.gallery img { width: 100%; height: 100%; object-fit: cover; display: block; transition: transform .6s var(--ease); }
.gallery figure:hover img { transform: scale(1.03); }
.gallery .g-wide { grid-column: span 2; grid-row: span 2; }
.gallery .g-tall { grid-row: span 2; }
.gallery figcaption {
  position: absolute; inset: auto 0 0 0; padding: 32px 14px 12px;
  background: linear-gradient(to top, rgb(15 17 19 / .85), rgb(15 17 19 / 0));
  color: #fff; font-size: 14px; font-weight: 500; line-height: 1.35;
}

.lines { margin-top: clamp(64px, 8vw, 104px); }
.lines-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); margin-top: 24px; border-top: 1px solid var(--night-line); }
.lines-grid > div { padding: 24px 40px 8px 0; }
.lines-grid > div + div { padding-left: 40px; border-left: 1px solid var(--night-line); }
.lines-grid h4 { font: 500 clamp(1.8rem, 3vw, 2.4rem)/1 var(--mono); color: #f0743f; margin-bottom: 12px; }
.lines-grid p { color: var(--on-night-2); max-width: 46ch; }

.steps-block { margin-top: clamp(64px, 8vw, 104px); }
.steps { --rule: var(--line); list-style: none; margin: 28px 0 0; padding: 0; display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 0; border-top: 1px solid var(--rule); }
.product-dark .steps { --rule: var(--night-line); }
.steps li { padding: 28px 28px 8px 0; position: relative; }
.steps li + li { padding-left: 28px; border-left: 1px solid var(--rule); }
.step-n { display: block; font: 500 clamp(2.6rem, 4vw, 3.6rem)/1 var(--mono); color: var(--accent); margin-bottom: 18px; }
.product-dark .step-n { color: #f0743f; }
.steps h4 { font-size: 1.25rem; font-weight: 700; margin-bottom: 8px; }
.steps p { color: var(--ink-2); max-width: 36ch; }
.product-dark .steps p { color: var(--on-night-2); }

.spec-block { margin-top: clamp(64px, 8vw, 104px); display: grid; grid-template-columns: minmax(0, 1fr); gap: 20px; }
.spec-head { display: flex; flex-wrap: wrap; justify-content: space-between; align-items: end; gap: 12px 40px; }
.table-scroll { overflow-x: auto; }
.spec { width: 100%; border-collapse: collapse; min-width: 520px; }
.spec th, .spec td { text-align: left; padding: 14px 16px 14px 0; border-bottom: 1px solid var(--line); }
.spec th { font-size: 13px; font-weight: 600; color: var(--ink-3); }
.spec td.num { white-space: nowrap; font-size: 15px; }
.spec tbody tr:hover { background: var(--paper-3); }
.product-dark .spec th, .product-dark .spec td { border-bottom-color: var(--night-line); }
.product-dark .spec th { color: var(--on-night-2); }
.product-dark .spec tbody tr:hover { background: var(--night-2); }

/* Thùng chống đâm, dải phân cách */
.unit { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1fr); gap: 40px 64px; align-items: start; }
.unit-text { margin-top: clamp(48px, 6vw, 72px); }
.unit-fig, .barrier-fig { margin: 0; border-radius: var(--radius); overflow: hidden; }
.unit-fig { background: #fff; }
.unit-fig img { display: block; width: 100%; height: auto; }
.barrier-fig svg { width: 100%; height: auto; }
.facts { list-style: none; margin: 0; padding: 0; }
.facts li { display: grid; grid-template-columns: 9em minmax(0, 1fr); gap: 16px; padding: 14px 0; border-top: 1px solid var(--line); }
.facts li > span:first-child { font-weight: 600; }
.facts li > span:last-child { color: var(--ink-2); }
.facts li:last-child { border-bottom: 1px solid var(--line); }
.facts .num { font-size: 15px; white-space: nowrap; color: var(--ink); }
.functions { margin: 0; }
.functions > div { display: grid; grid-template-columns: 9.5em minmax(0, 1fr); gap: 16px; padding: 14px 0; border-bottom: 1px solid var(--line); }
.functions > div:first-child { border-top: 2px solid var(--ink); }
.functions dt { font-weight: 700; }
.functions dd { margin: 0; color: var(--ink-2); }

.barrier { display: grid; grid-template-columns: minmax(0, 1.6fr) minmax(0, 1fr); gap: 32px 56px; align-items: center; }
.d-callouts circle { fill: var(--ink); }
.d-callouts text { font: 600 24px var(--font); fill: var(--paper); text-anchor: middle; }
.callout-list { margin: 0; padding: 0; list-style: none; counter-reset: c; display: grid; gap: 0; }
.callout-list li { counter-increment: c; position: relative; padding: 12px 0 12px 44px; border-top: 1px solid var(--line); color: var(--ink-2); }
.callout-list li:last-child { border-bottom: 1px solid var(--line); }
.callout-list li::before { content: counter(c); position: absolute; left: 0; top: 11px; display: grid; place-items: center; width: 28px; height: 28px; border-radius: 50%; background: var(--ink); color: var(--paper); font-weight: 600; font-size: 14px; }
.callout-list strong { color: var(--ink); font-weight: 600; }
.note-end { margin-top: 40px; }

/* Standards */
.standards { padding: clamp(72px, 9vw, 120px) 0; }
.std-list { list-style: none; margin: 32px 0 0; padding: 0; border-top: 2px solid var(--ink); }
.std-list li { display: grid; grid-template-columns: minmax(180px, .45fr) minmax(0, 1fr); gap: 12px 40px; padding: 22px 0; border-bottom: 1px solid var(--line); align-items: baseline; }
.std-code { font: 500 clamp(1.1rem, 1.6vw, 1.35rem) var(--mono); }
.std-list li span:last-child { color: var(--ink-2); max-width: 64ch; }

/* Resources */
.resources { padding-bottom: clamp(72px, 9vw, 120px); }
.res-head { display: flex; flex-wrap: wrap; justify-content: space-between; align-items: end; gap: 12px 40px; }
.res-head p { color: var(--ink-2); }
.res-list { list-style: none; margin: 32px 0 0; padding: 0; border-top: 2px solid var(--ink); }
.res-list li { display: grid; grid-template-columns: 32px minmax(0, 1fr) auto; gap: 20px; align-items: center; padding: 22px 0; border-bottom: 1px solid var(--line); }
.res-icon { width: 28px; height: 28px; color: var(--ink-3); }
.res-list h3 { font-size: 1.15rem; font-weight: 700; margin-bottom: 4px; }
.res-list p { color: var(--ink-2); font-size: 15px; }

/* Contact */
.contact { background: var(--accent); color: var(--on-accent); padding: clamp(72px, 9vw, 120px) 0; }
.contact-grid { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1.15fr); gap: 48px 80px; align-items: start; }
.contact h2 { font-size: clamp(2rem, 4vw, 3.4rem); font-weight: 800; letter-spacing: -0.03em; margin-bottom: 20px; }
.contact-copy > p { font-size: 1.1rem; max-width: 44ch; color: #fff3ec; }
.contact-lines { list-style: none; margin: 36px 0 0; padding: 0; }
.contact-lines li { display: grid; gap: 2px; padding: 14px 0; border-top: 1px solid rgb(255 255 255 / .35); }
.contact-lines span { font-size: 14px; color: #fff3ec; }
.contact-lines a { font-size: 1.3rem; font-weight: 600; text-decoration: none; }
.contact-lines a:hover { text-decoration: underline; text-decoration-color: #fff; }
.contact ::selection { background: var(--ink); color: var(--paper); }
.contact :focus-visible { outline-color: #fff; }

.contact-form { background: var(--paper); color: var(--ink); border-radius: var(--radius); padding: clamp(24px, 3vw, 40px); display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 20px; box-shadow: 0 24px 48px -24px rgb(60 20 4 / .55); }
.contact-form :focus-visible { outline-color: var(--accent); }
.field { display: grid; gap: 6px; align-content: start; }
.field-wide, .form-foot { grid-column: 1 / -1; }
.field label { font-weight: 600; font-size: 14px; }
.opt { font-weight: 400; color: var(--ink-3); }
.field input, .field select, .field textarea {
  width: 100%; min-height: 46px; padding: 10px 14px; border: 1px solid var(--line); border-radius: 8px;
  background: #f7f6f2; color: var(--ink); font: 400 16px/1.4 var(--font); caret-color: var(--accent);
  transition: border-color .15s var(--ease), background-color .15s var(--ease);
}
.field textarea { resize: vertical; min-height: 110px; }
.field input:hover, .field select:hover, .field textarea:hover { border-color: var(--ink-3); }
.field input:focus, .field select:focus, .field textarea:focus { outline: none; border-color: var(--ink); background: #fff; box-shadow: 0 0 0 3px rgb(194 65 12 / .25); }
.field ::placeholder { color: #6f7378; }
.field [aria-invalid="true"] { border-color: #b42318; background: #fdf3f2; }
.err { font-size: 14px; color: #b42318; }
.form-foot { display: flex; flex-wrap: wrap; align-items: center; gap: 12px 20px; }
.form-status { font-size: 15px; color: var(--ink-2); }

/* Footer */
.site-footer { background: var(--night); color: var(--on-night-2); padding: 64px 0 28px; font-size: 15px; }
.footer-grid { display: grid; grid-template-columns: 2fr 1fr 1fr; gap: 32px; }
.site-footer .brand-name { color: var(--on-night); display: block; margin-bottom: 6px; }
.company { margin: 20px 0 0; display: grid; gap: 6px; }
.company > div { display: grid; grid-template-columns: 10.5em minmax(0, 1fr); gap: 12px; }
.company dt { color: var(--on-night); font-weight: 600; }
.company dd { margin: 0; }
.contact-hours { margin-top: 20px; color: #fff3ec; font-size: 15px; }
.foot-h { color: var(--on-night); font-weight: 600; margin-bottom: 10px; }
.site-footer ul { list-style: none; margin: 0; padding: 0; display: grid; gap: 6px; }
.site-footer a { text-decoration: none; }
.site-footer a:hover { color: var(--on-night); text-decoration: underline; }
.foot-base { margin-top: 48px; padding-top: 20px; border-top: 1px solid var(--night-line); font-size: 13px; }
.product-dark ::selection, .site-footer ::selection { background: #f0743f; color: var(--night); }

/* Responsive */
@media (max-width: 960px) {
  .nav-toggle { display: grid; }
  .site-nav { position: absolute; top: 100%; left: 0; right: 0; background: var(--paper); border-bottom: 1px solid var(--line); padding: 8px var(--gutter) 20px; display: none; }
  .site-nav.is-open { display: block; }
  .site-nav > ul { flex-direction: column; align-items: stretch; gap: 0; }
  .site-nav a, .sub-toggle { width: 100%; justify-content: space-between; border-radius: 8px; }
  .sub { position: static; min-width: 0; box-shadow: none; background: var(--paper-2); display: none; opacity: 1; visibility: visible; transform: none; margin: 4px 0 8px; }
  .has-sub.is-open .sub { display: block; }
  .nav-cta { margin: 12px 0 0; }
  .brand-sub { display: none; }

  .hero-head, .product-head, .layers, .unit, .barrier, .contact-grid { grid-template-columns: 1fr; }
  .slide { grid-template-columns: 1fr; min-height: 0; }
  .slide-fig { aspect-ratio: 16 / 10; }
  .ch-row { grid-template-columns: 1fr; }
  .gallery { grid-template-columns: repeat(2, minmax(0, 1fr)); grid-auto-rows: 180px; }
  .gallery .g-tall { grid-row: span 2; }
  .lines-grid { grid-template-columns: 1fr; }
  .lines-grid > div, .lines-grid > div + div { padding: 24px 0 8px; border-left: 0; }
  .lines-grid > div + div { border-top: 1px solid var(--night-line); }
  .steps { grid-template-columns: 1fr; }
  .steps li, .steps li + li { padding: 24px 0 16px; border-left: 0; }
  .steps li + li { border-top: 1px solid var(--rule); }
  .footer-grid { grid-template-columns: 1fr 1fr; }
  .footer-grid > div:first-child { grid-column: 1 / -1; }
}
@media (max-width: 600px) {
  body { font-size: 16px; }
  .carousel-bar { flex-direction: column-reverse; align-items: stretch; }
  .tabs { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); overflow: visible; }
  .tabs button { padding: 0 6px; font-size: 14px; }
  .carousel-arrows { justify-content: flex-end; }
  .functions > div, .facts li { grid-template-columns: 1fr; gap: 4px; }
  .std-list li { grid-template-columns: 1fr; }
  .res-list li { grid-template-columns: 28px minmax(0, 1fr); }
  .res-list .btn { grid-column: 2; justify-self: start; }
  .contact-form { grid-template-columns: 1fr; }
  /* Sơ đồ thu nhỏ theo bề rộng màn hình: tăng cỡ chữ trong đơn vị SVG để vẫn đọc được */
  .ch-fig .d-label text { font-size: 27px; }
  .ch-fig .d-label .d-mono { font-size: 24px; }
}


/* Subpages, Breadcrumbs, Resource Actions & Print Datasheet */
.res-actions { display: flex; flex-wrap: wrap; gap: 10px; align-items: center; }
.breadcrumb { padding-top: 20px; font-size: 14px; color: var(--ink-3); }
.breadcrumb ol { list-style: none; margin: 0; padding: 0; display: flex; flex-wrap: wrap; gap: 8px; align-items: center; }
.breadcrumb li + li::before { content: "/"; margin-right: 8px; color: var(--line); }
.breadcrumb a { text-decoration: none; color: var(--ink-2); }
.breadcrumb a:hover { color: var(--accent); text-decoration: underline; }
.page-hero { padding-block: clamp(32px, 5vw, 64px) clamp(40px, 6vw, 72px); border-bottom: 1px solid var(--line); }
.page-hero h1 { font-size: clamp(2.1rem, 4.4vw, 3.8rem); font-weight: 800; letter-spacing: -0.03em; line-height: 1.08; margin-bottom: 16px; }
.page-meta { display: flex; flex-wrap: wrap; gap: 12px 24px; margin-top: 20px; font-size: 14px; color: var(--ink-3); }
.page-actions { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 24px; }
.prose-grid { display: grid; grid-template-columns: minmax(0, 1.3fr) minmax(0, 1fr); gap: 32px 56px; align-items: start; margin-top: 32px; }
.prose-block { display: grid; gap: 16px; }
.prose-block h3 { font-size: 1.3rem; font-weight: 700; margin-top: 8px; }
.prose-block ul { margin: 0; padding-left: 20px; display: grid; gap: 8px; color: var(--ink-2); }
.product-dark .prose-block ul { color: var(--on-night-2); }
.qa-list { margin: 28px 0 0; display: grid; gap: 0; border-top: 2px solid var(--ink); }
.qa-item { padding: 22px 0; border-bottom: 1px solid var(--line); display: grid; gap: 8px; }
.qa-item h3 { font-size: 1.15rem; font-weight: 700; }
.qa-item p { color: var(--ink-2); max-width: 72ch; }
@media (max-width: 960px) {
  .prose-grid { grid-template-columns: 1fr; }
}
@media print {
  .site-header, .skip, .contact, .page-actions, .res-actions, .nav-toggle { display: none !important; }
  body { background: #fff; color: #000; font-size: 12pt; }
  .product-dark, .product-tint, .site-footer { background: #fff !important; color: #000 !important; }
  .product { padding: 20pt 0; }
}

/* Nút liên hệ nhanh góc phải dưới */
.quick-contact {
  position: fixed; right: max(16px, env(safe-area-inset-right)); bottom: max(16px, env(safe-area-inset-bottom));
  z-index: 40; display: flex; flex-direction: column; align-items: flex-end; gap: 12px;
}
.quick-btn {
  display: flex; align-items: center; gap: 10px; height: 54px; min-width: 54px; padding: 0 15px;
  border-radius: 999px; color: #fff; text-decoration: none; font-weight: 600; font-size: 15px;
  box-shadow: 0 6px 18px rgba(23, 25, 27, .28);
  transition: transform .2s var(--ease), box-shadow .2s var(--ease);
}
.quick-btn svg { width: 24px; height: 24px; flex: none; }
.quick-zalo { background: #0068ff; }
.quick-zalo svg { width: 28px; height: 28px; margin: 0 -2px; }
.quick-call { background: var(--accent); }
.quick-label { max-width: 0; overflow: hidden; white-space: nowrap; transition: max-width .3s var(--ease); }
.quick-btn:hover, .quick-btn:focus-visible { transform: translateY(-2px); box-shadow: 0 10px 24px rgba(23, 25, 27, .32); text-decoration: none; }
.quick-btn:hover .quick-label, .quick-btn:focus-visible .quick-label { max-width: 160px; }
.quick-btn:not(:hover):not(:focus-visible) { gap: 0; }
@media (max-width: 600px) {
  .quick-contact { gap: 10px; }
  .quick-btn { height: 50px; min-width: 50px; padding: 0 13px; }
}
@media (prefers-reduced-motion: reduce) { .quick-btn, .quick-label { transition: none; } }
@media print { .quick-contact { display: none !important; } }