/* QG800 展示站样式（零依赖）。工业黑白风格：深色主视觉段 + 浅色信息段。颜色令牌集中在 :root。 */
:root {
  --bg: #ffffff;
  --band: #f2f4f6;
  --ink: #111417;
  --muted: #5d6670;
  --line: #dde2e7;
  --accent: #0a6cff;
  --accent-ink: #ffffff;
  --card: #ffffff;
  --stage: #eef1f4;
  --dark: #0a0c0f;
  --dark-2: #13171c;
  --dark-ink: #f3f5f7;
  --dark-muted: #9aa4ae;
  --dark-line: #262c33;
  --radius: 4px;
  --max: 1240px;
  color-scheme: light dark;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0f1216;
    --band: #151a20;
    --ink: #e9edf1;
    --muted: #a0aab4;
    --line: #2a313a;
    --accent: #4d94ff;
    --accent-ink: #06101f;
    --card: #181d24;
    --stage: #e9edf1;
  }
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 64px; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font: 16px/1.6 "Inter", system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  -webkit-font-smoothing: antialiased;
}
img { max-width: 100%; height: auto; display: block; }
a { color: var(--accent); }
h1, h2, h3, h4 { line-height: 1.1; margin: 0 0 .6em; letter-spacing: -.02em; font-weight: 800; }
h2 { font-size: clamp(1.8rem, 3.4vw, 2.6rem); }
h3 { font-size: 1.2rem; letter-spacing: -.01em; }
.display { font-size: clamp(2.2rem, 5vw, 3.8rem); }
.wrap { max-width: var(--max); margin: 0 auto; padding: 0 16px; }
.band { background: var(--band); }
section { padding: 88px 0; }
.top-gap { margin-top: 48px; }
.fine { color: var(--muted); font-size: .82rem; }

/* 深色段 */
.dark { background: var(--dark); color: var(--dark-ink); --muted: var(--dark-muted); --line: var(--dark-line); }
.dark a:not(.btn) { color: var(--dark-ink); }

.topbar { position: sticky; top: 0; z-index: 10; background: rgba(10, 12, 15, .92); backdrop-filter: blur(8px); border-bottom: 1px solid var(--dark-line); }
.bar { display: flex; align-items: center; justify-content: space-between; gap: 16px; height: 60px; }
.brand { font-weight: 800; letter-spacing: .04em; text-transform: uppercase; text-decoration: none; font-size: 51px; line-height: 1; flex-shrink: 0; }
nav { display: flex; align-items: center; gap: 22px; }
nav a { text-decoration: none; font-size: .88rem; letter-spacing: .02em; opacity: .85; }
nav a:hover { opacity: 1; }
@media (max-width: 860px) { nav a:not(.btn) { display: none; } }

.btn {
  display: inline-block; background: var(--accent); color: var(--accent-ink); text-decoration: none;
  padding: 13px 28px; border-radius: var(--radius); font-weight: 700; border: 2px solid var(--accent); cursor: pointer;
  font-size: .95rem; letter-spacing: .02em;
}
.btn.ghost { background: transparent; color: inherit; border-color: currentColor; }
.btn.small { padding: 7px 16px; font-size: .85rem; opacity: 1; }
.cta-row { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 28px; }
.eyebrow { text-transform: uppercase; letter-spacing: .18em; font-size: .78rem; color: var(--accent); font-weight: 700; margin: 0 0 14px; }

.hero { position: relative; overflow: hidden; min-height: min(92vh, 900px); display: flex; align-items: flex-end; padding: 0; background: var(--dark); isolation: isolate; }
.hero-bg { position: absolute; inset: 0; z-index: -2; overflow: hidden; }
.hero-bg video { width: 100%; height: 100%; object-fit: cover; display: block; }
.hero-shade { position: absolute; inset: 0; z-index: -1; background: linear-gradient(180deg, rgba(10, 12, 15, .35) 0%, rgba(10, 12, 15, .15) 35%, rgba(10, 12, 15, .85) 100%); }
.hero-inner { width: 100%; padding-top: 120px; padding-bottom: 40px; }
.hero-title { margin-bottom: 8px; }
.hero h1 { font-size: clamp(3.5rem, 11vw, 8rem); line-height: .9; margin: 0 0 12px; letter-spacing: -.05em; text-shadow: 0 2px 24px rgba(0, 0, 0, .4); }
.hero .tagline { margin: 0; max-width: 46rem; color: var(--dark-ink); text-shadow: 0 1px 12px rgba(0, 0, 0, .5); }
.keywords { list-style: none; margin: 36px 0 0; padding: 20px 0 0; display: grid; grid-template-columns: repeat(4, 1fr); gap: 0 24px; border-top: 1px solid rgba(255, 255, 255, .25); }
.keywords li { display: flex; flex-direction: column; }
.keywords strong { font-size: clamp(1.8rem, 3.4vw, 2.8rem); font-weight: 800; letter-spacing: -.03em; line-height: 1; }
.keywords span { color: var(--dark-muted); font-size: .8rem; text-transform: uppercase; letter-spacing: .14em; margin-top: 6px; }
.hero .cta-row { margin-top: 24px; align-items: center; }
.btn.watch { display: inline-flex; align-items: center; justify-content: center; gap: 8px; background: #141414; border-color: #666; color: #fff; }
.btn.watch:hover { background: #262626; border-color: #fff; }
.btn.watch:focus-visible { outline: 2px solid #fff; outline-offset: 4px; }
.youtube-icon { width: 28px; height: 20px; flex-shrink: 0; }
.carousel { position: relative; margin: 48px 0 8px; aspect-ratio: 16 / 8; border-radius: 6px; overflow: hidden; background: linear-gradient(180deg, #ffffff 0%, #e6eaee 100%); }
.slide { position: absolute; inset: 0; margin: 0; padding: 28px 40px 44px; opacity: 0; transition: opacity .8s ease; pointer-events: none; }
.slide.is-active { opacity: 1; pointer-events: auto; }
.slide img { width: 100%; height: 100%; object-fit: contain; }
.slide.photo { padding: 0; }
.slide.photo img { object-fit: cover; }
.showcase { padding-top: 0; }
.showcase .carousel { margin-top: 32px; }
.placeholder { height: 100%; display: grid; place-items: center; border: 2px dashed #b7c0ca; border-radius: 6px; color: #6b7682; text-transform: uppercase; letter-spacing: .14em; font-size: .85rem; }
.dots { position: absolute; left: 0; right: 0; bottom: 14px; display: flex; justify-content: center; gap: 8px; }
.dots button { width: 28px; height: 4px; padding: 0; border: 0; border-radius: 2px; background: rgba(17, 20, 23, .2); cursor: pointer; }
.dots button[aria-current="true"] { background: var(--accent); }
@media (max-width: 520px) { .carousel { aspect-ratio: 4 / 3; } .slide { padding: 16px 16px 36px; } .slide.photo { padding: 0; } }
.lead { font-size: 1.15rem; }
.tagline { font-size: clamp(1.1rem, 2.2vw, 1.35rem); font-weight: 600; margin: 0 0 14px; }
@media (max-width: 900px) {
  .keywords { grid-template-columns: repeat(2, 1fr); gap: 18px 16px; }
}

.two-col { display: grid; grid-template-columns: 1.4fr 1fr; gap: 40px; align-items: start; }
.card { background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); padding: 20px; }
.ticks { list-style: none; padding: 0; margin: 0; }
.ticks li { padding: 6px 0 6px 26px; position: relative; border-bottom: 1px solid var(--line); }
.ticks li:last-child { border-bottom: 0; }
.ticks li::before { content: "✓"; position: absolute; left: 0; color: var(--accent); font-weight: 700; }

.showcase-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(210px, 1fr)); gap: 16px; margin-top: 28px; }
.tile { display: flex; flex-direction: column; margin: 0; background: linear-gradient(180deg, #ffffff 0%, #e6eaee 100%); border: 1px solid var(--line); border-radius: var(--radius); overflow: hidden; }
.tile img { width: 100%; aspect-ratio: 3 / 4; object-fit: contain; padding: 20px; }
.tile-pane { display: flex; flex: 0 0 auto; }
.tile-pane[hidden] { display: none; }
.tile-pane img { flex: 1; }
.tile .tile-pane img.fill { padding: 0; object-fit: cover; object-position: 50% 50%; }
.tile-brand { width: 100%; aspect-ratio: 3 / 4; display: flex; flex-direction: column; align-items: center; justify-content: center; gap: 6px; padding: 20px; text-align: center; color: var(--ink); }
.tile-brand strong { font-size: 1.6rem; letter-spacing: .02em; }
.tile-brand span { font-size: .9rem; opacity: .7; }
.tile-media { position: relative; }
.tile-tabs { position: absolute; left: 12px; right: 12px; bottom: 10px; display: flex; gap: 6px; }
.tile-tabs button { flex: 1; font: inherit; font-size: .78rem; font-weight: 700; padding: 5px 6px; border: 1px solid var(--line); border-radius: 999px; background: #fff; cursor: pointer; }
.tile-tabs button[aria-pressed="true"] { background: var(--accent); border-color: var(--accent); color: var(--accent-ink); }
.tile figcaption { flex: 1; padding: 14px 20px; border-top: 1px solid var(--line); background: var(--card); font-weight: 700; text-transform: uppercase; letter-spacing: .04em; font-size: .95rem; }

.intro { max-width: 860px; color: var(--muted); margin-bottom: 32px; }
.principle { display: grid; grid-template-columns: 1.2fr 1fr; gap: 64px; align-items: center; padding: 72px 0; border-top: 1px solid var(--dark-line); }
.principle:nth-of-type(even) figure { order: 2; }
.principle figure { margin: 0; border-radius: 6px; padding: 28px; background: linear-gradient(180deg, #ffffff 0%, #e3e8ed 100%); }
.principle figure img { width: 100%; height: 360px; object-fit: contain; }
.principle figure.photo { padding: 0; overflow: hidden; }
.principle figure.photo img { height: 416px; object-fit: cover; }
.principle-no { font-size: clamp(3.5rem, 8vw, 6rem); font-weight: 800; line-height: 1; margin: 0; color: transparent; -webkit-text-stroke: 1.5px #3a4552; letter-spacing: -.04em; }
.principle-label { text-transform: uppercase; color: var(--accent); font-weight: 700; letter-spacing: .2em; font-size: .8rem; margin: 10px 0 10px; }
.principle h3 { font-size: clamp(1.7rem, 3.4vw, 2.6rem); line-height: 1.08; }
.principle p { color: var(--dark-muted); font-size: 1.08rem; max-width: 520px; }
.principle-list { list-style: none; padding: 0; margin: 8px 0 0; display: grid; grid-template-columns: 1fr 1fr; gap: 1px; background: var(--dark-line); border: 1px solid var(--dark-line); max-width: 560px; }
.principle-list li { background: var(--dark-2); padding: 14px 16px; color: var(--dark-muted); font-size: .92rem; }
.principle-list strong { display: block; color: var(--dark-ink); text-transform: uppercase; letter-spacing: .08em; font-size: .72rem; margin-bottom: 4px; }
.closing { text-align: center; background: linear-gradient(180deg, var(--dark) 0%, #0d1b2e 100%); }
.closing .lead { max-width: none; margin: 0 auto; color: var(--dark-muted); }
.closing .tagline { color: var(--accent); text-transform: uppercase; letter-spacing: .12em; font-size: .95rem; }
.closing .cta-row { justify-content: center; }
@media (max-width: 900px) {
  .principle { grid-template-columns: 1fr; gap: 28px; padding: 48px 0; }
  .principle:nth-of-type(even) figure { order: 0; }
}
@media (max-width: 520px) { .principle-list { grid-template-columns: 1fr; } }

.table-scroll { overflow-x: auto; -webkit-overflow-scrolling: touch; margin: 16px 0; }
table { border-collapse: collapse; width: 100%; background: var(--card); font-size: .95rem; }
caption { text-align: left; font-weight: 700; padding: 0 0 8px; }
th, td { border: 1px solid var(--line); padding: 10px 12px; text-align: left; vertical-align: top; }
thead th { background: var(--dark); color: var(--dark-ink); font-size: .82rem; text-transform: uppercase; letter-spacing: .06em; }
.specs th[scope="row"] { width: 32%; font-weight: 600; }
.specs td.num { width: 3.5em; color: var(--muted); }
.specs ul { margin: 0; padding-left: 1.1em; }
.capacity td, .capacity thead th { text-align: center; white-space: nowrap; }
.ref { font-size: .8rem; text-decoration: none; margin-left: 4px; }

.option-grid { display: grid; align-items: start; grid-template-columns: repeat(auto-fill, minmax(220px, 1fr)); gap: 16px; }
.option-grid img { height: 140px; width: 100%; object-fit: contain; margin-bottom: 10px; }
.option-grid h4 { margin-bottom: 6px; }
dl { margin: 0; }
.option-grid dt { font-size: .8rem; color: var(--muted); }
.option-grid dd { margin: 0 0 6px; }


.standards > div { border-left: 3px solid var(--accent); padding: 4px 0 4px 14px; margin: 0 0 16px; }
.standards dt { font-weight: 700; }
.standards dt span { font-weight: 400; }
.standards dd { margin: 4px 0 0; color: var(--muted); }
.standards > div:target { background: var(--card); }

.enquiry { display: grid; grid-template-columns: 1fr 1fr; gap: 14px; }
.enquiry label { display: flex; flex-direction: column; gap: 4px; font-size: .9rem; font-weight: 600; }
.enquiry .full { grid-column: 1 / -1; margin: 0; }
.enquiry input, .enquiry select, .enquiry textarea {
  font: inherit; padding: 10px; border: 1px solid var(--line); border-radius: 6px; background: var(--bg); color: var(--ink); font-weight: 400;
}
.form-error { color: #c0392b; font-weight: 600; }

.footer { padding: 40px 0; }


@media (max-width: 900px) {
  .two-col { grid-template-columns: 1fr; }
}
@media (max-width: 520px) {
  .enquiry { grid-template-columns: 1fr; }
  section { padding: 56px 0; }
  .hero { min-height: 86vh; }
  .hero-inner { padding-top: 96px; padding-bottom: 28px; }
}

.hp { position: absolute; left: -9999px; width: 1px; height: 1px; overflow: hidden; }