/* ============================================================
   拓能智械 TNTservo — 展示型官网
   设计语言：纯白底 / 极细字重 / 深蓝 #004E96 点状强调 / 零圆角零阴影
   ============================================================ */

:root {
  --blue: #004E96;
  --blue-deep: #003D76;
  --blue-logo: #2D54A1;
  --nav-blue: #1B72B0;
  --ink: #111111;
  --ink-soft: #333333;
  --muted: #5A6873;
  --placeholder: #8A9096;
  --gray-bg: #F7F7F7;
  --hairline: #E8E8E8;
  --container: 1240px;
  --header-h: 78px;
  --font: "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", Roboto, Helvetica, Arial, sans-serif;
}

*, *::before, *::after { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: var(--font);
  font-size: 16px;
  line-height: 1.7;
  color: var(--ink);
  background: #fff;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

img { max-width: 100%; }
a { color: inherit; text-decoration: none; }
button { font-family: inherit; }

.svg-sprite { position: absolute; width: 0; height: 0; overflow: hidden; }

.visually-hidden {
  position: absolute !important;
  width: 1px; height: 1px;
  padding: 0; margin: -1px;
  overflow: hidden; clip: rect(0 0 0 0);
  white-space: nowrap; border: 0;
}

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

/* ── header ─────────────────────────────────────────────────── */
.site-header {
  position: sticky;
  top: 0;
  z-index: 60;
  background: #fff;
  transition: box-shadow .25s ease;
}
.site-header.is-scrolled { box-shadow: 0 1px 0 var(--hairline), 0 6px 18px rgba(10, 30, 50, .05); }

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  min-height: var(--header-h);
}

.wordmark { display: flex; flex-direction: column; align-items: center; line-height: 1.05; }
.wordmark-cn {
  font-size: 25px;
  font-weight: 700;
  letter-spacing: .08em;
  color: var(--blue-logo);
}
.wordmark-en {
  font-size: 11px;
  font-weight: 700;
  letter-spacing: .3em;
  text-transform: uppercase;
  color: var(--nav-blue);
  margin-top: 3px;
  padding-left: .3em; /* 补偿末字符字距，视觉居中 */
}

.nav { display: flex; align-items: center; gap: clamp(16px, 3vw, 46px); }
.nav a {
  font-size: 15px;
  font-weight: 600;
  color: var(--nav-blue);
  padding: 6px 0;
  position: relative;
  white-space: nowrap;
  transition: color .2s ease;
}
.nav a::after {
  content: "";
  position: absolute;
  left: 0; right: 0; bottom: 0;
  height: 2px;
  background: var(--blue);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform .25s ease;
}
.nav a:hover, .nav a.is-active { color: var(--blue); }
.nav a:hover::after, .nav a.is-active::after { transform: scaleX(1); }
.nav-search { letter-spacing: .06em; }

.nav-toggle {
  display: none;
  width: 42px; height: 42px;
  border: 0;
  background: none;
  padding: 0;
  cursor: pointer;
}
.nav-toggle span {
  display: block;
  width: 22px; height: 1.6px;
  margin: 5px auto;
  background: var(--ink);
  transition: transform .25s ease, opacity .2s ease;
}
.nav-toggle:focus-visible { outline: 2px solid var(--blue); outline-offset: 3px; }
.nav-toggle[aria-expanded="true"] span:nth-child(1) { transform: translateY(6.6px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] span:nth-child(2) { opacity: 0; }
.nav-toggle[aria-expanded="true"] span:nth-child(3) { transform: translateY(-6.6px) rotate(-45deg); }

/* ── hero ───────────────────────────────────────────────────── */
.hero { position: relative; overflow: hidden; background: #0d1a26; }
.hero-track { display: flex; transition: transform .85s cubic-bezier(.4, 0, .2, 1); }
.hero-slide { position: relative; min-width: 100%; }
.hero-slide img {
  display: block;
  width: 100%;
  height: clamp(340px, 43vw, 700px);
  object-fit: cover;
  object-position: center 45%;
}
.hero-slide::after {
  content: "";
  position: absolute;
  inset: 0;
  background:
    linear-gradient(180deg, rgba(6, 20, 33, .2) 0%, rgba(6, 20, 33, 0) 34%, rgba(6, 20, 33, .52) 100%),
    linear-gradient(90deg, rgba(6, 20, 33, .34) 0%, rgba(6, 20, 33, 0) 42%);
  pointer-events: none;
}
.hero-caption {
  position: absolute;
  left: max(24px, calc((100vw - var(--container)) / 2 + 24px));
  bottom: clamp(56px, 6vw, 72px);
  z-index: 2;
  color: #fff;
  font-size: clamp(14px, 1.05vw, 16px);
  font-weight: 500;
  letter-spacing: .1em;
  text-shadow: 0 1px 14px rgba(4, 16, 27, .6);
}

.hero-arrow {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  z-index: 3;
  width: 40px; height: 40px;
  display: grid; place-items: center;
  border: 0;
  border-radius: 0;
  background: rgba(25, 25, 25, .62);
  color: #fff;
  cursor: pointer;
  transition: background .2s ease;
}
.hero-arrow:hover { background: rgba(0, 78, 150, .9); }
.hero-arrow svg { width: 20px; height: 20px; fill: none; stroke: currentColor; stroke-width: 1.5; stroke-linecap: round; stroke-linejoin: round; }
.hero-prev { left: 22px; }
.hero-next { right: 22px; }

.hero-dots {
  position: absolute;
  left: 50%;
  bottom: 26px;
  transform: translateX(-50%);
  z-index: 3;
  display: flex;
  gap: 10px;
}
.hero-dot {
  width: 8px; height: 8px;
  padding: 0;
  border: 0;
  background-color: rgba(255, 255, 255, .8);
  cursor: pointer;
  transition: width .35s ease, background-color .25s ease;
}
.hero-dot.is-active { width: 26px; background-color: #fff; }

/* ── sections ───────────────────────────────────────────────── */
.section { padding: clamp(48px, 6vw, 84px) 0; scroll-margin-top: calc(var(--header-h) + 16px); }
.section-products { padding-bottom: clamp(56px, 7vw, 96px); }

.section-title {
  margin: 0;
  text-align: center;
  font-size: clamp(21px, 2.1vw, 31px);
  font-weight: 400;
  letter-spacing: .01em;
  color: var(--ink);
}
.section-sub {
  margin: 10px 0 0;
  text-align: center;
  font-size: 12px;
  font-weight: 500;
  letter-spacing: .22em;
  text-transform: uppercase;
  color: var(--muted);
}
.section-sub + .product-grid { margin-top: clamp(26px, 3vw, 42px); }
.section-title:not(:first-child) { margin-top: clamp(48px, 5.5vw, 76px); }

/* ── product grid ───────────────────────────────────────────── */
.product-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: clamp(28px, 3.4vw, 48px) clamp(16px, 2.4vw, 34px);
}

.product-tile { text-align: center; }
.tile-media {
  position: relative;
  aspect-ratio: 8 / 7;
  display: flex;
  align-items: center;
  justify-content: center;
}
.tile-media img {
  width: 100%;
  height: 100%;
  object-fit: contain;
  transition: transform .5s cubic-bezier(.3, 0, .2, 1);
}
.product-tile:hover .tile-media img { transform: translateY(-4px) scale(1.03); }

.tile-name {
  margin: 14px 0 0;
  font-size: clamp(16px, 1.4vw, 20px);
  font-weight: 500;
  letter-spacing: .01em;
  color: var(--ink);
}
.tile-sub {
  margin: 5px 0 0;
  font-size: 13px;
  font-weight: 400;
  color: var(--ink-soft);
}
.product-tile:hover .tile-name { color: var(--blue); }

/* ── applications ───────────────────────────────────────────── */
.app-grid {
  list-style: none;
  margin: clamp(30px, 3.4vw, 46px) 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: clamp(26px, 3vw, 42px) 24px;
}
.app-grid li {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  gap: 4px;
}
.app-icon {
  width: 36px; height: 36px;
  flex: 0 0 auto;
  fill: none;
  stroke: var(--blue);
  stroke-width: 1.4;
  stroke-linecap: round;
  stroke-linejoin: round;
  margin-bottom: 8px;
  transition: transform .35s cubic-bezier(.3, 0, .2, 1);
}
.app-grid li:hover .app-icon { transform: translateY(-3px); }
.app-grid b { font-size: 15px; font-weight: 600; letter-spacing: .04em; }
.app-grid span { font-size: 12.5px; color: var(--muted); }

/* ── about ──────────────────────────────────────────────────── */
.section-about {
  background: var(--gray-bg);
  padding: clamp(52px, 6vw, 80px) 0 clamp(56px, 6.4vw, 88px);
}
.about-title {
  margin: 0 auto;
  max-width: 900px;
  text-align: center;
  text-wrap: balance;
  font-size: clamp(20px, 2vw, 30px);
  font-weight: 400;
  letter-spacing: .01em;
}
.about-title-en {
  margin: 12px 0 0;
  text-align: center;
  font-size: 12px;
  font-weight: 500;
  letter-spacing: .18em;
  text-transform: uppercase;
  color: var(--muted);
}
.about-cols {
  margin-top: clamp(30px, 3.6vw, 46px);
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: clamp(24px, 3.4vw, 52px);
}
.about-label {
  margin: 0 0 12px;
  font-size: 15px;
  font-weight: 500;
  letter-spacing: .04em;
}
.about-col p {
  margin: 0 0 10px;
  font-size: 13.5px;
  line-height: 1.9;
  color: #1a1a1a;
}
.about-col p strong { font-weight: 700; }

.blue-band {
  background: var(--blue);
  color: #fff;
  min-height: clamp(48px, 4.4vw, 74px);
  display: flex;
  align-items: center;
}
.blue-band-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 8px 24px;
  padding-top: 14px;
  padding-bottom: 14px;
}
.blue-band-inner p {
  margin: 0;
  font-size: 13px;
  font-weight: 400;
  letter-spacing: .14em;
  color: rgba(255, 255, 255, .92);
}
.blue-band-actions {
  display: flex;
  align-items: baseline;
  gap: 28px;
}
.band-mail {
  border-bottom: 0 !important;
  color: rgba(255, 255, 255, .82) !important;
  font-weight: 400 !important;
  letter-spacing: .06em !important;
}
.band-cta {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 13px;
  font-weight: 600;
  letter-spacing: .12em;
  color: #fff;
  border-bottom: 1px solid rgba(255, 255, 255, .5);
  padding-bottom: 2px;
  transition: border-color .2s ease;
}
.band-cta:hover { border-color: #fff; }
.band-arrow {
  width: 15px; height: 15px;
  fill: none;
  stroke: currentColor;
  stroke-width: 1.6;
  stroke-linecap: round;
  stroke-linejoin: round;
}

/* ── footer ─────────────────────────────────────────────────── */
.site-footer { background: #fff; padding-top: clamp(40px, 4.4vw, 56px); }
.footer-cols {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr)) minmax(290px, 1.6fr);
  gap: clamp(24px, 2.6vw, 36px);
}
.footer-heading {
  margin: 0 0 14px;
  font-size: 15px;
  font-weight: 700;
  color: var(--ink);
}
.footer-heading--news { font-weight: 600; letter-spacing: .01em; }
.footer-col a {
  display: block;
  font-size: 13.5px;
  line-height: 1.7;
  color: var(--ink-soft);
  margin-bottom: 8px;
  transition: color .2s ease;
}
.footer-col a:hover { color: var(--blue); }
.footer-col address {
  font-style: normal;
  font-size: 13.5px;
  line-height: 1.9;
  color: var(--ink-soft);
}
.footer-meta { margin: 10px 0 0; font-size: 13.5px; color: var(--ink-soft); }
.footer-meta a { display: inline; color: var(--blue); }

.news-note { margin: 0 0 16px; font-size: 13px; color: var(--muted); }
.news-form { display: flex; align-items: stretch; }
.news-form input {
  flex: 1 1 auto;
  min-width: 0;
  height: 44px;
  padding: 0 12px;
  border: 1px solid #DCDCDC;
  border-radius: 0;
  font-size: 14px;
  color: var(--ink);
  background: #fff;
  font-family: inherit;
}
.news-form input::placeholder { color: var(--placeholder); }
.news-form input:focus { outline: none; border-color: var(--blue); }
.news-form button {
  flex: 0 0 auto;
  height: 44px;
  padding: 0 22px;
  border: 0;
  border-radius: 0;
  background: var(--blue);
  color: #fff;
  font-size: 14px;
  font-weight: 500;
  cursor: pointer;
  transition: background .2s ease;
}
.news-form button:hover { background: var(--blue-deep); }
.news-msg { margin: 10px 0 0; font-size: 12.5px; min-height: 18px; color: var(--blue); }
.news-msg.is-error { color: #b3261e; }

.social-row { display: flex; gap: 11px; margin-top: 22px; }
.social-row a {
  width: 28px; height: 28px;
  border-radius: 50%;
  background: #111;
  display: grid;
  place-items: center;
  margin: 0;
  transition: background .2s ease;
}
.social-row a:hover { background: var(--blue); }
.social-row svg { width: 16px; height: 16px; fill: #fff; }

.hairline { margin: 36px 0 0; border: 0; border-top: 1px solid var(--hairline); }
.footer-bottom {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: 6px 28px;
  padding: 18px 0 32px;
}
.copyright { margin: 0; font-size: 13px; color: var(--ink-soft); }
.copyright--en { font-size: 12px; color: var(--muted); }
.legal-links { margin: 0; display: flex; gap: 8px; font-size: 12px; color: var(--muted); }
.legal-links a:hover { color: var(--blue); }

/* ── gentle entrance (content is always visible, never JS-gated) ─ */
@media (prefers-reduced-motion: no-preference) {
  .reveal { animation: reveal-in .7s cubic-bezier(.25, .8, .3, 1) both; }
  @keyframes reveal-in {
    from { opacity: .001; transform: translateY(12px); }
    to { opacity: 1; transform: none; }
  }
}

/* ── responsive ─────────────────────────────────────────────── */
@media (max-width: 1080px) {
  .footer-cols { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .footer-col--news { grid-column: 1 / -1; }
  .footer-bottom { padding-bottom: 26px; }
}

@media (max-width: 900px) {
  :root { --header-h: 68px; }

  .nav {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    background: #fff;
    border-top: 1px solid var(--hairline);
    box-shadow: 0 14px 24px rgba(10, 30, 50, .08);
    padding: 8px 24px 18px;
    display: none;
  }
  .nav.is-open { display: flex; }
  .nav a { padding: 13px 0; border-bottom: 1px solid #F4F4F4; }
  .nav a::after { display: none; }
  .nav-toggle { display: block; }

  .product-grid { grid-template-columns: repeat(2, 1fr); }
  .app-grid { grid-template-columns: repeat(2, 1fr); }
  .about-cols { grid-template-columns: 1fr; gap: 28px; }
}

@media (max-width: 620px) {
  .product-grid { grid-template-columns: 1fr; gap: 26px; }
  .tile-media { max-width: 320px; margin: 0 auto; aspect-ratio: 1 / 1; }
  .hero-slide img { height: clamp(360px, 52vh, 460px); }
  .hero-caption { letter-spacing: .06em; bottom: 64px; }
  .hero-arrow { display: none; }
  .hero-dot {
    box-sizing: content-box;
    padding: 14px 9px;
    background-clip: content-box;
  }
  .hero-dot.is-active { background-clip: content-box; }
  .hero-dots { bottom: 4px; gap: 0; }
  .app-grid { gap: 30px 18px; }
  .blue-band-inner { justify-content: flex-start; padding-top: 18px; padding-bottom: 18px; }
  .blue-band-actions { gap: 18px; }
  .footer-cols { grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 28px 20px; }
  .footer-col--contact { grid-column: auto; }
  .footer-col--news { grid-column: 1 / -1; }
  .footer-col a { padding: 5px 0; }
  .social-row a { width: 38px; height: 38px; }
  .social-row svg { width: 18px; height: 18px; }
  .footer-bottom { padding-bottom: 22px; }
  .copyright--en { flex-basis: 100%; font-size: 11.5px; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .reveal { animation: none; }
  .hero-track { transition: none; }
  .product-tile:hover .tile-media img { transform: none; }
}