/* Layout: a page built like a lift shaft. Each section is a "floor" with its number shown in the side rail; the cabin capacity plaque is the product card. */
:root {
  --bg: #EDEFF1;
  --surface: #FFFFFF;
  --fg: #12171B;
  --muted: #56606A;
  --line: #CDD3D8;
  --bar: #F7F8F9;
  --accent: #F58A2E;
  --accent-ink: #A24F00;
  --on-accent: #1B1200;
  --led-bg: #0B0E11;
  --led-fg: #FFB020;
  --f-display: "Barlow Condensed", "Arial Narrow", sans-serif;
  --f-body: "Be Vietnam Pro", system-ui, -apple-system, "Segoe UI", sans-serif;
  --gutter-l: max(16px, env(safe-area-inset-left, 0px));
  --gutter-r: max(16px, env(safe-area-inset-right, 0px));
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #0F1317; --surface: #171C21; --fg: #E8ECEF; --muted: #98A2AB; --line: #2B333A;
    --bar: #12171B; --accent: #F58A2E; --accent-ink: #FFA04D; --on-accent: #1B1200;
    --led-bg: #06080A; --led-fg: #FFB020; color-scheme: dark;
  }
}
:root[data-theme="dark"] {
  --bg: #0F1317; --surface: #171C21; --fg: #E8ECEF; --muted: #98A2AB; --line: #2B333A;
  --bar: #12171B; --accent: #F58A2E; --accent-ink: #FFA04D; --on-accent: #1B1200;
  --led-bg: #06080A; --led-fg: #FFB020; color-scheme: dark;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 84px; }
body { background: var(--bg); color: var(--fg); font-family: var(--f-body); font-size: 16px; line-height: 1.65; margin: 0; }
body::before { content: ""; position: fixed; inset: 0 0 auto; height: env(safe-area-inset-top, 0px); background: var(--bar); z-index: 40; }
a { color: inherit; }
h1, h2, h3 { font-family: var(--f-display); font-weight: 700; line-height: 1.05; text-wrap: balance; margin: 0; letter-spacing: .005em; }
h1 { font-size: clamp(2.6rem, 7vw, 4.6rem); text-transform: uppercase; }
h2 { font-size: clamp(2rem, 4.5vw, 3rem); text-transform: uppercase; }
h3 { font-size: 1.5rem; }
p { margin: 0; }
.wrap { max-width: 1160px; margin-inline: auto; padding-left: var(--gutter-l); padding-right: var(--gutter-r); }
.eyebrow { font-family: var(--f-display); font-weight: 600; font-size: 1rem; letter-spacing: .14em; text-transform: uppercase; color: var(--accent-ink); }
:focus-visible { outline: 3px solid var(--accent); outline-offset: 2px; }
.btn { display: inline-flex; align-items: center; justify-content: center; gap: .5rem; min-height: 48px; padding: 0 1.4rem; font: 600 .95rem var(--f-body); text-decoration: none; border: 2px solid var(--fg); background: transparent; color: var(--fg); cursor: pointer; border-radius: 4px; }
.btn:hover { background: var(--fg); color: var(--bg); }
.btn.primary { background: var(--accent); border-color: var(--accent); color: var(--on-accent); }
.btn.primary:hover { filter: brightness(1.08); background: var(--accent); color: var(--on-accent); }

/* Header */
.site-header { position: sticky; top: env(safe-area-inset-top, 0px); z-index: 50; background: var(--bar); border-bottom: 1px solid var(--line); }
.site-header .wrap { display: flex; align-items: center; gap: 1rem; min-height: 68px; }
.brand { display: flex; align-items: center; gap: .7rem; text-decoration: none; min-width: 0; }
.logo-tile { flex: none; background: #fff; border-radius: 6px; padding: 3px 6px; display: grid; place-items: center; }
.logo-tile img { height: 38px; width: auto; display: block; }
.footer-logo { background: #fff; border-radius: 6px; padding: 8px; width: min(220px, 100%); margin-bottom: 1rem; }
.footer-logo img { width: 100%; height: auto; display: block; }
.brand b { font-family: var(--f-display); font-size: 1.45rem; text-transform: uppercase; line-height: 1; display: block; }
.brand small { display: block; font-size: .7rem; color: var(--muted); letter-spacing: .08em; text-transform: uppercase; }
.nav { display: none; margin-left: auto; gap: 1.4rem; }
.nav a { text-decoration: none; font-weight: 500; font-size: .93rem; padding: .4rem 0; border-bottom: 2px solid transparent; }
.nav a:hover { border-bottom-color: var(--accent); }
.head-cta { margin-left: auto; display: flex; align-items: center; gap: .6rem; }
.head-cta .btn { min-height: 42px; padding: 0 1rem; }
.menu-btn { min-height: 42px; padding: 0 .9rem; }
.mobile-nav { border-top: 1px solid var(--line); background: var(--bar); }
.mobile-nav .wrap { display: grid; padding-block: .5rem 1rem; }
.mobile-nav a { padding: .7rem 0; text-decoration: none; border-bottom: 1px solid var(--line); font-weight: 500; }
@media (min-width: 980px) {
  .nav { display: flex; }
  .head-cta { margin-left: 1.5rem; }
  .menu-btn, .mobile-nav { display: none !important; }
}
@media (max-width: 520px) { .head-cta .hot-text { display: none; } .brand b { font-size: 1.1rem; } .brand small { display: none; } }
@media (max-width: 480px) { .head-cta .btn.primary { display: none; } }

/* Hero */
.hero { padding-block: clamp(2.5rem, 6vw, 5rem); }
.hero .wrap { display: grid; gap: 2.5rem; align-items: center; }
.hero-copy { display: grid; gap: 1.4rem; min-width: 0; }
.hero-copy p.lead { font-size: 1.1rem; color: var(--muted); max-width: 52ch; }
.hero-actions { display: flex; flex-wrap: wrap; gap: .8rem; }
.led { display: inline-grid; grid-template-columns: auto 1fr; gap: .3rem 1rem; align-items: center; background: var(--led-bg); color: var(--led-fg); padding: .9rem 1.2rem; border-radius: 4px; width: fit-content; max-width: 100%; border: 1px solid #2A2F35; }
.led .floor { font-family: var(--f-display); font-weight: 600; font-size: 3.2rem; line-height: 1; font-variant-numeric: tabular-nums; text-shadow: 0 0 14px rgba(255,176,32,.55); }
.led .info { font-family: var(--f-display); font-size: 1.05rem; letter-spacing: .12em; text-transform: uppercase; line-height: 1.25; }
.shaft-art { justify-self: center; width: min(100%, 360px); }
.shaft-art svg { width: 100%; height: auto; display: block; }
.s-wall { fill: var(--surface); stroke: var(--line); stroke-width: 2; }
.s-line { stroke: var(--line); stroke-width: 1.5; }
.s-num { fill: var(--muted); font: 600 13px var(--f-display); letter-spacing: .08em; }
.s-cab { fill: var(--surface); stroke: var(--fg); stroke-width: 3; }
.s-door { fill: #B8C0C7; stroke: var(--fg); stroke-width: 2; }
.s-cable { stroke: var(--fg); stroke-width: 2; }
.s-cw { fill: var(--muted); }
.s-led { fill: var(--led-bg); }
.s-ledt { fill: var(--led-fg); font: 700 15px var(--f-display); }
@keyframes ride { from { transform: translateY(0); } to { transform: translateY(-250px); } }
@keyframes ride-cw { from { transform: translateY(-250px); } to { transform: translateY(0); } }
.cab { animation: ride 14s ease-in-out infinite alternate; }
.cw { animation: ride-cw 14s ease-in-out infinite alternate; }
@media (min-width: 900px) { .hero .wrap { grid-template-columns: 1.15fr .85fr; } }

/* Trust strip */
.strip { background: var(--fg); color: var(--bg); }
.strip .wrap { display: grid; gap: 1px; grid-template-columns: repeat(auto-fit, minmax(210px, 1fr)); padding-block: 1.1rem; }
.strip div { padding: .4rem 0; font-size: .95rem; display: flex; gap: .7rem; align-items: baseline; }
.strip b { font-family: var(--f-display); font-size: 1.25rem; text-transform: uppercase; letter-spacing: .04em; }

/* Sections */
.section { padding-block: clamp(3rem, 7vw, 5.5rem); }
.section.alt { background: var(--surface); border-block: 1px solid var(--line); }
.sec-head { display: grid; gap: .8rem; margin-bottom: 2.2rem; max-width: 62ch; }
.sec-head p { color: var(--muted); }

/* Products: cabin capacity plaque */
.products { display: grid; gap: 1.2rem; grid-template-columns: repeat(auto-fit, minmax(min(100%, 330px), 1fr)); }
.plaque { background: var(--surface); border: 1px solid var(--line); border-radius: 4px; display: grid; grid-template-rows: auto 1fr; min-width: 0; }
.plaque-top { background: #C9CFD4; color: #12171B; padding: 1.2rem 1.4rem; display: flex; justify-content: space-between; align-items: end; gap: 1rem; flex-wrap: wrap; border-bottom: 4px solid var(--accent); }
.plaque-top .cap { font-family: var(--f-display); font-weight: 700; font-size: 2.6rem; line-height: 1; font-variant-numeric: tabular-nums; }
.plaque-top .cap small { font-size: 1.1rem; letter-spacing: .08em; margin-left: .25rem; }
.plaque-top .ppl { font-family: var(--f-display); font-size: 1.05rem; letter-spacing: .1em; text-transform: uppercase; font-weight: 600; }
.plaque-body { padding: 1.4rem; display: grid; gap: 1rem; align-content: start; }
.plaque-body p { color: var(--muted); font-size: .95rem; }
.plaque dl { margin: 0; display: grid; grid-template-columns: auto 1fr; gap: .35rem 1rem; font-size: .92rem; }
.plaque dt { color: var(--muted); }
.plaque dd { margin: 0; font-weight: 500; text-align: right; font-variant-numeric: tabular-nums; }
.plaque .btn { margin-top: .3rem; width: 100%; }
.note { color: var(--muted); font-size: .85rem; margin-top: 1.2rem; }

/* Process */
.steps { list-style: none; padding: 0; margin: 0; display: grid; gap: 0; grid-template-columns: repeat(auto-fit, minmax(min(100%, 240px), 1fr)); border-top: 2px solid var(--fg); counter-reset: s; }
.steps li { padding: 1.4rem 1.2rem 1.6rem 0; display: grid; gap: .5rem; align-content: start; counter-increment: s; border-bottom: 1px solid var(--line); }
.steps li::before { content: "T" counter(s); font-family: var(--f-display); font-weight: 600; font-size: 1.1rem; letter-spacing: .1em; color: var(--accent-ink); }
.steps p { color: var(--muted); font-size: .95rem; }

/* Projects */
.chips { display: flex; flex-wrap: wrap; gap: .5rem; margin-bottom: 1.6rem; }
.chip { min-height: 40px; padding: 0 1rem; border: 1px solid var(--line); background: var(--surface); color: var(--fg); font: 500 .9rem var(--f-body); border-radius: 999px; cursor: pointer; }
.chip[aria-pressed="true"] { background: var(--fg); color: var(--bg); border-color: var(--fg); }
.projects { display: grid; gap: 1.2rem; grid-template-columns: repeat(auto-fill, minmax(min(100%, 320px), 1fr)); }
.project { background: var(--surface); border: 1px solid var(--line); border-radius: 4px; overflow: hidden; min-width: 0; }
.project[hidden] { display: none; }
.ph { aspect-ratio: 4 / 3; max-width: 100%; position: relative; display: grid; place-items: end start; padding: .8rem; background:
  repeating-linear-gradient(90deg, transparent 0 46px, rgba(120,130,140,.18) 46px 48px),
  linear-gradient(160deg, #AEB6BD, #7F8A93); color: #fff; }
.ph.b { background: repeating-linear-gradient(90deg, transparent 0 46px, rgba(120,130,140,.18) 46px 48px), linear-gradient(160deg, #B9B3A6, #8C8474); }
.ph.c { background: repeating-linear-gradient(90deg, transparent 0 46px, rgba(120,130,140,.18) 46px 48px), linear-gradient(160deg, #9DB0BC, #5F7584); }
.ph span { font-size: .72rem; letter-spacing: .1em; text-transform: uppercase; background: rgba(0,0,0,.55); padding: .2rem .5rem; border-radius: 2px; }
.shot { aspect-ratio: 4 / 5; max-width: 100%; overflow: hidden; background: var(--line); }
.shot img { width: 100%; height: 100%; object-fit: cover; display: block; }
.project-body { padding: 1rem 1.2rem 1.3rem; display: grid; gap: .4rem; }
.project-body .meta { font-size: .82rem; color: var(--muted); display: flex; flex-wrap: wrap; gap: .3rem 1rem; }

/* Blog */
.posts { display: grid; gap: 1.2rem; grid-template-columns: repeat(auto-fit, minmax(min(100%, 300px), 1fr)); }
.post { display: grid; gap: .7rem; align-content: start; padding: 1.4rem 0 1.2rem; border-top: 2px solid var(--fg); min-width: 0; }
.post .tag { font-size: .8rem; letter-spacing: .1em; text-transform: uppercase; color: var(--accent-ink); font-weight: 600; }
.post p { color: var(--muted); font-size: .95rem; }
.post a.more { font-weight: 600; text-decoration-thickness: 2px; text-underline-offset: 4px; text-decoration-color: var(--accent); }

/* FAQ */
.faq { max-width: 820px; display: grid; }
.faq details { border-bottom: 1px solid var(--line); }
.faq details:first-child { border-top: 1px solid var(--line); }
.faq summary { cursor: pointer; padding: 1.1rem 2rem 1.1rem 0; font-weight: 600; list-style: none; position: relative; }
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after { content: "+"; position: absolute; right: 0; top: .9rem; font: 600 1.6rem var(--f-display); color: var(--accent-ink); }
.faq details[open] summary::after { content: "–"; }
.faq details p { padding: 0 2rem 1.2rem 0; color: var(--muted); }

/* Contact */
.contact { display: grid; gap: 2.5rem; }
@media (min-width: 900px) { .contact { grid-template-columns: .9fr 1.1fr; } }
.channels { display: grid; gap: .8rem; align-content: start; }
.channel { display: flex; align-items: center; gap: 1rem; padding: .9rem 1rem; background: var(--surface); border: 1px solid var(--line); border-radius: 4px; text-decoration: none; min-width: 0; }
.channel:hover { border-color: var(--fg); }
.channel .ico { flex: none; width: 44px; height: 44px; border-radius: 50%; display: grid; place-items: center; color: #fff; }
.channel strong { display: block; font-size: 1rem; line-height: 1.3; overflow-wrap: anywhere; }
.channel span.sub { font-size: .82rem; color: var(--muted); }
.copy { margin-left: auto; flex: none; min-height: 36px; padding: 0 .8rem; border: 1px solid var(--line); background: var(--bg); color: var(--fg); border-radius: 4px; cursor: pointer; font: 500 .8rem var(--f-body); }
.form { background: var(--surface); border: 1px solid var(--line); border-radius: 4px; padding: clamp(1.2rem, 3vw, 2rem); display: grid; gap: 1rem; min-width: 0; }
.form .row { display: grid; gap: 1rem; grid-template-columns: repeat(auto-fit, minmax(min(100%, 200px), 1fr)); }
.form label { display: grid; gap: .35rem; font-size: .88rem; font-weight: 500; }
.form input, .form select, .form textarea { font: 400 1rem var(--f-body); color: var(--fg); background: var(--bg); border: 1px solid var(--line); border-radius: 4px; padding: .7rem .8rem; min-height: 46px; width: 100%; }
.form textarea { min-height: 96px; resize: vertical; }
.form .actions { display: flex; flex-wrap: wrap; gap: .7rem; }
.hp { position: absolute; left: -9999px; width: 1px; height: 1px; overflow: hidden; }
.status { font-size: .9rem; color: var(--accent-ink); min-height: 1.4em; }

/* Footer */
.site-footer { background: var(--fg); color: var(--bg); padding-block: 2.5rem 6rem; }
.site-footer .wrap { display: grid; gap: 2rem; grid-template-columns: repeat(auto-fit, minmax(min(100%, 240px), 1fr)); }
.site-footer h3 { font-size: 1.15rem; letter-spacing: .08em; text-transform: uppercase; margin-bottom: .6rem; }
.site-footer p, .site-footer a { font-size: .92rem; opacity: .85; }
.site-footer a { display: block; padding: .15rem 0; text-decoration: none; }
.site-footer a:hover { opacity: 1; text-decoration: underline; }
.copyright { grid-column: 1 / -1; border-top: 1px solid rgba(128,128,128,.4); padding-top: 1rem; font-size: .82rem; opacity: .7; }

/* Floating contact buttons */
.fab { position: fixed; right: max(12px, env(safe-area-inset-right, 0px)); bottom: calc(12px + env(safe-area-inset-bottom, 0px)); display: flex; flex-direction: column; gap: 10px; z-index: 60; }
.fab a { position: relative; width: 52px; height: 52px; border-radius: 50%; display: grid; place-items: center; color: #fff; text-decoration: none; box-shadow: 0 4px 14px rgba(0,0,0,.28); font: 700 .78rem var(--f-body); }
.fab a:hover { transform: scale(1.06); }
.fab a .tip { position: absolute; right: 62px; white-space: nowrap; background: var(--fg); color: var(--bg); font: 500 .8rem var(--f-body); padding: .3rem .6rem; border-radius: 4px; opacity: 0; pointer-events: none; transition: opacity .15s; }
.fab a:hover .tip, .fab a:focus-visible .tip { opacity: 1; }
.c-zalo { background: #0068FF; } .c-mess { background: linear-gradient(135deg, #00B2FF, #006AFF 55%, #A334FA); } .c-fb { background: #1877F2; } .c-tel { background: #D9231A; }

/* Floor rail (wide screens) */
.rail { display: none; position: fixed; left: 14px; top: 50%; transform: translateY(-50%); z-index: 30; flex-direction: column; gap: 6px; }
.rail a { width: 34px; height: 34px; display: grid; place-items: center; font: 600 .95rem var(--f-display); text-decoration: none; color: var(--muted); border: 1px solid var(--line); background: var(--surface); border-radius: 3px; font-variant-numeric: tabular-nums; }
.rail a[aria-current="true"] { background: var(--led-bg); color: var(--led-fg); border-color: var(--led-bg); }
@media (min-width: 1360px) { .rail { display: flex; } }
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } .cab, .cw { animation: none; } .fab a:hover { transform: none; } }

/* Bài viết */
.article-view { padding-block: clamp(2rem, 5vw, 4rem); }
.art { max-width: 760px; margin-inline: auto; min-width: 0; }
.crumbs { font-size: .85rem; color: var(--muted); display: flex; flex-wrap: wrap; gap: .3rem .6rem; margin-bottom: 1.2rem; }
.crumbs a { text-decoration-color: var(--accent); text-underline-offset: 3px; }
.art h1 { font-size: clamp(2.1rem, 5vw, 3.2rem); margin-bottom: .8rem; }
.art .byline { color: var(--muted); font-size: .88rem; margin-bottom: 1.8rem; }
.art h2 { font-size: clamp(1.6rem, 3.4vw, 2.1rem); margin: 2.2rem 0 .8rem; text-transform: none; }
.art h3 { font-size: 1.3rem; margin: 1.5rem 0 .5rem; }
.art p, .art li { max-width: 68ch; }
.art p { margin-bottom: 1rem; }
.art ul, .art ol { padding-left: 1.3rem; margin: 0 0 1rem; display: grid; gap: .4rem; }
.art .answer { background: var(--surface); border-top: 3px solid var(--accent); padding: 1rem 1.2rem; margin-bottom: 1.6rem; }
.art .checklist { list-style: none; padding-left: 0; }
.art .checklist li { padding-left: 1.6rem; position: relative; }
.art .checklist li::before { content: "✓"; position: absolute; left: 0; color: var(--accent-ink); font-weight: 700; }
.art figure { margin: 1rem 0 1.2rem; max-width: 420px; }
.art figure img { width: 100%; height: auto; display: block; border: 1px solid var(--line); }
.art figcaption { font-size: .85rem; color: var(--muted); margin-top: .4rem; }
.table-wrap { overflow-x: auto; margin: 0 0 1.4rem; border: 1px solid var(--line); }
.art table { border-collapse: collapse; width: 100%; min-width: 520px; font-size: .93rem; background: var(--surface); }
.art th, .art td { text-align: left; padding: .7rem .9rem; border-bottom: 1px solid var(--line); vertical-align: top; }
.art th { font-family: var(--f-display); font-size: 1.05rem; letter-spacing: .06em; text-transform: uppercase; background: var(--bar); }
.cta-box { margin-top: 2.4rem; padding: 1.4rem; background: var(--fg); color: var(--bg); display: grid; gap: .8rem; }
.cta-box h2 { margin: 0; font-size: 1.7rem; color: var(--bg); }
.cta-box p { margin: 0; opacity: .85; }
.cta-box .row { display: flex; flex-wrap: wrap; gap: .7rem; }
.cta-box .btn { border-color: var(--bg); color: var(--bg); }
.cta-box .btn:hover { background: var(--bg); color: var(--fg); }
.cta-box .btn.primary { background: var(--accent); border-color: var(--accent); color: var(--on-accent); }
.related { margin-top: 2.2rem; display: grid; gap: .5rem; }
.related h2 { font-size: 1.4rem; margin: 0 0 .3rem; }
.related a { font-weight: 600; text-decoration-color: var(--accent); text-underline-offset: 4px; }