/* ==========================================================================
   黑石投资工程有限公司 · 企业官网
   品牌色：黑石红 #C40202 / 深空黑 #16181D / 暖灰底 #F6F5F3
   ========================================================================== */

:root {
  --red: #c40202;
  --red-dark: #9c0202;
  --red-soft: #fdeaea;
  --ink: #16181d;
  --ink-2: #3c4049;
  --ink-3: #6b7078;
  --line: #e6e3df;
  --bg: #ffffff;
  --bg-alt: #f6f5f3;
  --bg-dark: #101216;
  --radius: 14px;
  --shadow: 0 10px 30px rgba(22, 24, 29, 0.08);
  --shadow-lg: 0 24px 60px rgba(22, 24, 29, 0.16);
  --header-h: 72px;
  --font: "PingFang SC", "Microsoft YaHei", "Segoe UI", "Helvetica Neue", Arial, sans-serif;
  --ease: cubic-bezier(0.22, 0.61, 0.36, 1);
}

* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body {
  font-family: var(--font);
  color: var(--ink);
  background: var(--bg);
  line-height: 1.75;
  font-size: 16px;
  overflow-x: hidden;
}
img { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }
ul { list-style: none; }
button { font-family: inherit; cursor: pointer; }

.container { width: min(1160px, 92%); margin-inline: auto; }

.skip-link {
  position: absolute; left: -999px; top: 8px; z-index: 200;
  background: var(--red); color: #fff; padding: 8px 16px; border-radius: 8px;
}
.skip-link:focus { left: 8px; }

/* ===== 按钮 ===== */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  padding: 13px 30px; border-radius: 999px; border: 1.5px solid transparent;
  font-size: 15px; font-weight: 600; letter-spacing: 0.02em;
  transition: transform 0.25s var(--ease), box-shadow 0.25s var(--ease),
              background 0.25s, color 0.25s, border-color 0.25s;
}
.btn-primary { background: var(--red); color: #fff; box-shadow: 0 8px 20px rgba(196, 2, 2, 0.28); }
.btn-primary:hover { background: var(--red-dark); transform: translateY(-2px); box-shadow: 0 12px 26px rgba(196, 2, 2, 0.36); }
.btn-ghost { border-color: rgba(255, 255, 255, 0.65); color: #fff; }
.btn-ghost:hover { background: rgba(255, 255, 255, 0.14); transform: translateY(-2px); }
.btn-sm { padding: 9px 20px; font-size: 14px; }
.btn-block { width: 100%; }
.btn:focus-visible, a:focus-visible, button:focus-visible {
  outline: 2px solid var(--red); outline-offset: 3px; border-radius: 6px;
}

/* ===== 顶部导航 ===== */
.site-header {
  position: fixed; inset: 0 0 auto 0; z-index: 100;
  height: var(--header-h);
  background: rgba(255, 255, 255, 0.6);
  backdrop-filter: blur(14px); -webkit-backdrop-filter: blur(14px);
  border-bottom: 1px solid transparent;
  transition: background 0.3s, border-color 0.3s, box-shadow 0.3s;
}
.site-header.scrolled {
  background: rgba(255, 255, 255, 0.94);
  border-bottom-color: var(--line);
  box-shadow: 0 6px 24px rgba(22, 24, 29, 0.06);
}
.header-inner { display: flex; align-items: center; justify-content: space-between; gap: 20px; height: 100%; }

.brand { display: flex; align-items: center; gap: 11px; min-width: 0; }
.brand-mark {
  width: 42px; height: 42px; flex: none;
  border-radius: 9px; object-fit: cover;
  box-shadow: 0 6px 14px rgba(22, 24, 29, 0.18);
}
.brand-text { display: flex; flex-direction: column; line-height: 1.25; }
.brand-zh { font-size: 17px; font-weight: 700; letter-spacing: 0.04em; }
.brand-en { font-size: 10px; letter-spacing: 0.22em; color: var(--ink-3); font-weight: 600; }

.site-nav ul { display: flex; gap: 4px; }
.site-nav a {
  display: block; padding: 8px 14px; border-radius: 8px;
  font-size: 15px; font-weight: 500; color: var(--ink-2);
  transition: color 0.2s, background 0.2s;
}
.site-nav a:hover, .site-nav a.active { color: var(--red); background: var(--red-soft); }

.header-actions { display: flex; align-items: center; gap: 10px; }
.lang-toggle {
  display: inline-flex; align-items: center; gap: 6px;
  padding: 8px 14px; border: 1px solid var(--line); border-radius: 999px;
  background: #fff; font-size: 13px; font-weight: 600; color: var(--ink-2);
  transition: border-color 0.2s, color 0.2s;
}
.lang-toggle:hover { border-color: var(--red); color: var(--red); }

.nav-toggle {
  display: none; flex-direction: column; justify-content: center; gap: 5px;
  width: 44px; height: 44px; padding: 10px;
  background: #fff; border: 1px solid var(--line); border-radius: 10px;
}
.nav-toggle span { display: block; height: 2px; background: var(--ink); border-radius: 2px; transition: transform 0.3s var(--ease), opacity 0.3s; }
.nav-toggle[aria-expanded="true"] span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] span:nth-child(2) { opacity: 0; }
.nav-toggle[aria-expanded="true"] span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ===== Hero ===== */
.hero {
  position: relative; min-height: 100svh;
  display: flex; align-items: center;
  padding: calc(var(--header-h) + 40px) 0 60px;
  color: #fff; isolation: isolate;
}
.hero-bg { position: absolute; inset: 0; z-index: -2; }
.hero-bg img { width: 100%; height: 100%; object-fit: cover; }
.hero-overlay {
  position: absolute; inset: 0; z-index: -1;
  background: linear-gradient(100deg, rgba(12, 13, 16, 0.86) 0%, rgba(12, 13, 16, 0.62) 46%, rgba(120, 6, 2, 0.42) 100%);
}
.hero-content { max-width: 860px; }
.hero-eyebrow {
  display: inline-flex; align-items: center; gap: 10px;
  font-size: 14px; font-weight: 600; letter-spacing: 0.14em;
  color: rgba(255, 255, 255, 0.85); margin-bottom: 18px;
}
.hero-eyebrow::before { content: ""; width: 34px; height: 2px; background: var(--red); }
.hero-title {
  font-size: clamp(34px, 6vw, 62px); line-height: 1.18; font-weight: 800;
  letter-spacing: 0.01em; margin-bottom: 20px;
  text-shadow: 0 4px 30px rgba(0, 0, 0, 0.35);
}
.hero-sub { font-size: clamp(15px, 2vw, 18px); color: rgba(255, 255, 255, 0.88); max-width: 620px; margin-bottom: 34px; }
.hero-actions { display: flex; flex-wrap: wrap; gap: 14px; margin-bottom: 56px; }

.hero-stats {
  display: grid; grid-template-columns: repeat(4, 1fr); gap: 10px;
  max-width: 640px; padding-top: 26px;
  border-top: 1px solid rgba(255, 255, 255, 0.22);
}
.hero-stats li { text-align: center; }
.hero-stats strong { display: block; font-size: clamp(26px, 4vw, 38px); font-weight: 800; color: #fff; line-height: 1.1; }
.hero-stats strong::after { content: "+"; color: var(--red); font-size: 0.7em; margin-left: 2px; }
.hero-stats span { font-size: 13px; color: rgba(255, 255, 255, 0.75); letter-spacing: 0.06em; }

/* ===== 通用 Section ===== */
.section { padding: 96px 0; }
.section-alt { background: var(--bg-alt); }
.grid-2 { display: grid; grid-template-columns: 1fr 1fr; gap: 60px; align-items: center; }
.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 26px; }

.section-head { max-width: 640px; margin-bottom: 52px; }
.section-eyebrow {
  color: var(--red); font-size: 13px; font-weight: 700;
  letter-spacing: 0.18em; text-transform: uppercase; margin-bottom: 12px;
}
.section-title { font-size: clamp(26px, 3.6vw, 40px); font-weight: 800; line-height: 1.3; margin-bottom: 16px; }
.section-desc { color: var(--ink-3); font-size: 16px; }

/* ===== 关于我们 ===== */
.about-media { position: relative; padding-bottom: 90px; }
.photo-frame {
  background: #fff; border-radius: var(--radius); overflow: hidden;
  box-shadow: var(--shadow-lg); border: 1px solid var(--line);
}
.photo-frame img { width: 100%; aspect-ratio: 4 / 3; object-fit: cover; }
.photo-frame figcaption {
  padding: 12px 18px; font-size: 13px; color: var(--ink-3);
  border-top: 1px solid var(--line); background: #fff;
}
.photo-sm { position: absolute; right: -8px; bottom: 0; width: 46%; z-index: 2; }
.photo-sm img { aspect-ratio: 3 / 3.6; object-fit: cover; }

.about-body p { color: var(--ink-2); margin-bottom: 16px; }
.about-points { margin-top: 28px; display: grid; gap: 14px; }
.about-points li {
  display: flex; align-items: baseline; gap: 14px;
  padding: 14px 18px; background: var(--bg-alt); border-radius: 12px;
  border-left: 3px solid var(--red);
}
.about-points strong { flex: none; font-size: 15px; color: var(--ink); }
.about-points span { font-size: 14px; color: var(--ink-3); }

/* ===== 业务范围 ===== */
.svc-card {
  background: #fff; border: 1px solid var(--line); border-radius: 18px;
  padding: 38px 34px; box-shadow: var(--shadow);
  transition: transform 0.35s var(--ease), box-shadow 0.35s var(--ease);
  position: relative; overflow: hidden;
}
.svc-card::before {
  content: ""; position: absolute; inset: 0 0 auto 0; height: 4px;
  background: linear-gradient(90deg, var(--red), #e8452c);
  transform: scaleX(0); transform-origin: left; transition: transform 0.4s var(--ease);
}
.svc-card:hover { transform: translateY(-6px); box-shadow: var(--shadow-lg); }
.svc-card:hover::before { transform: scaleX(1); }
.svc-icon {
  display: grid; place-items: center; width: 60px; height: 60px;
  background: var(--red-soft); color: var(--red);
  border-radius: 16px; margin-bottom: 22px;
}
.svc-icon svg { width: 30px; height: 30px; }
.svc-card h3 { font-size: 22px; font-weight: 700; margin-bottom: 12px; }
.svc-card > p { color: var(--ink-2); font-size: 15px; margin-bottom: 18px; }
.svc-list { display: grid; gap: 8px; }
.svc-list li {
  position: relative; padding-left: 22px;
  font-size: 14px; color: var(--ink-3); font-weight: 500;
}
.svc-list li::before {
  content: ""; position: absolute; left: 0; top: 0.62em;
  width: 10px; height: 10px; border-radius: 3px;
  background: var(--red-soft); border: 2px solid var(--red);
}

.usp-bar {
  margin-top: 44px; display: grid; grid-template-columns: repeat(4, 1fr);
  background: var(--bg-dark); border-radius: 18px; overflow: hidden;
  box-shadow: var(--shadow-lg);
}
.usp { padding: 28px 16px; text-align: center; position: relative; }
.usp + .usp::before { content: ""; position: absolute; left: 0; top: 25%; height: 50%; width: 1px; background: rgba(255, 255, 255, 0.12); }
.usp strong { display: block; color: #fff; font-size: 19px; font-weight: 700; letter-spacing: 0.06em; }
.usp span { font-size: 12px; color: rgba(255, 255, 255, 0.5); letter-spacing: 0.12em; }

/* ===== 工程实力 ===== */
.fleet-list { margin-top: 30px; display: grid; gap: 12px; }
.fleet-list li {
  display: flex; align-items: center; gap: 18px;
  padding: 16px 20px; background: #fff;
  border: 1px solid var(--line); border-radius: 14px;
  transition: transform 0.3s var(--ease), box-shadow 0.3s var(--ease), border-color 0.3s;
}
.fleet-list li:hover { transform: translateX(6px); border-color: var(--red); box-shadow: var(--shadow); }
.fleet-num {
  flex: none; min-width: 56px; text-align: center;
  font-size: 30px; font-weight: 800; color: var(--red); line-height: 1;
  font-variant-numeric: tabular-nums;
}
.fleet-list strong { display: block; font-size: 16px; }
.fleet-list div span { font-size: 13px; color: var(--ink-3); }

/* ===== 工程现场 ===== */
.gallery-grid {
  display: grid; grid-template-columns: repeat(3, 1fr);
  gap: 18px;
}
.gallery-grid button {
  display: block; width: 100%; padding: 0; border: 0; border-radius: 14px;
  overflow: hidden; background: none; position: relative;
}
.gallery-grid img {
  width: 100%; aspect-ratio: 1; object-fit: cover;
  transition: transform 0.5s var(--ease);
}
.gallery-grid button::after {
  content: ""; position: absolute; inset: 0;
  background: linear-gradient(to top, rgba(16, 18, 22, 0.45), transparent 55%);
  opacity: 0; transition: opacity 0.35s;
}
.gallery-grid button:hover img { transform: scale(1.06); }
.gallery-grid button:hover::after { opacity: 1; }
.gallery-grid button:focus-visible { outline: 3px solid var(--red); outline-offset: 3px; }

/* ===== 企业文化 ===== */
.cul-card {
  position: relative; background: #fff;
  border: 1px solid var(--line); border-radius: 18px;
  padding: 40px 32px; box-shadow: var(--shadow);
  transition: transform 0.35s var(--ease), box-shadow 0.35s var(--ease);
}
.cul-card:hover { transform: translateY(-6px); box-shadow: var(--shadow-lg); }
.cul-accent { background: linear-gradient(150deg, var(--red), #7e0303); border-color: transparent; }
.cul-accent .cul-tag { background: rgba(255, 255, 255, 0.18); color: #fff; }
.cul-accent .cul-main, .cul-accent .cul-sub { color: #fff; }
.cul-accent .cul-sub { color: rgba(255, 255, 255, 0.82); }
.cul-tag {
  display: inline-block; padding: 5px 14px; border-radius: 999px;
  background: var(--red-soft); color: var(--red);
  font-size: 12px; font-weight: 700; letter-spacing: 0.1em; margin-bottom: 20px;
}
.cul-main { font-size: 21px; font-weight: 800; line-height: 1.4; margin-bottom: 12px; }
.cul-sub { font-size: 14px; color: var(--ink-3); }

/* ===== 联系我们 ===== */
.contact-body p { color: var(--ink-2); margin-bottom: 30px; }
.contact-list { display: grid; gap: 20px; }
.contact-list li { display: flex; gap: 16px; align-items: flex-start; }
.ct-icon {
  flex: none; display: grid; place-items: center; width: 46px; height: 46px;
  background: var(--red-soft); color: var(--red); border-radius: 12px;
}
.ct-icon svg { width: 21px; height: 21px; }
.contact-list strong { display: block; font-size: 15px; margin-bottom: 2px; }
.contact-list div span { font-size: 14px; color: var(--ink-3); }
.contact-list a:hover { color: var(--red); }

.contact-form-wrap { width: 100%; }
.contact-form {
  background: #fff; border: 1px solid var(--line); border-radius: 18px;
  padding: 36px 32px; box-shadow: var(--shadow-lg);
}
.contact-form h3 { font-size: 21px; font-weight: 800; margin-bottom: 6px; }
.form-note { font-size: 13px; color: var(--ink-3); margin-bottom: 22px; }
.form-field { margin-bottom: 16px; }
.form-field label { display: block; font-size: 13.5px; font-weight: 600; margin-bottom: 6px; color: var(--ink-2); }
.form-field input, .form-field textarea {
  width: 100%; padding: 12px 14px; font: inherit; font-size: 14.5px;
  border: 1.5px solid var(--line); border-radius: 10px; background: var(--bg-alt);
  transition: border-color 0.2s, background 0.2s, box-shadow 0.2s;
  resize: vertical;
}
.form-field input:focus, .form-field textarea:focus {
  outline: none; border-color: var(--red); background: #fff;
  box-shadow: 0 0 0 3px rgba(196, 2, 2, 0.12);
}
.form-field input[aria-invalid="true"], .form-field textarea[aria-invalid="true"] { border-color: #d64545; }
.form-status { margin-top: 12px; font-size: 13.5px; min-height: 1.4em; color: #1c7c3c; }
.form-status.error { color: #d64545; }

/* ===== 页脚 ===== */
.site-footer { background: var(--bg-dark); color: rgba(255, 255, 255, 0.72); padding: 52px 0 40px; }
.footer-inner { display: grid; grid-template-columns: 1fr auto; gap: 28px; align-items: start; }
.footer-brand { display: flex; gap: 12px; align-items: center; }
.footer-brand strong { display: block; color: #fff; font-size: 16px; }
.footer-brand span { font-size: 12px; letter-spacing: 0.04em; }
.footer-brand .brand-mark { width: 40px; height: 40px; }
.footer-nav { display: flex; flex-wrap: wrap; gap: 4px 22px; }
.footer-nav a { font-size: 14px; padding: 4px 0; transition: color 0.2s; }
.footer-nav a:hover { color: #fff; }
.footer-copy { grid-column: 1 / -1; padding-top: 20px; border-top: 1px solid rgba(255, 255, 255, 0.1); font-size: 13px; }

/* ===== 回到顶部 ===== */
.back-top {
  position: fixed; right: 22px; bottom: 22px; z-index: 90;
  width: 46px; height: 46px; border-radius: 12px; border: 0;
  background: var(--red); color: #fff;
  display: grid; place-items: center;
  box-shadow: 0 10px 24px rgba(196, 2, 2, 0.35);
  opacity: 0; visibility: hidden; transform: translateY(12px);
  transition: opacity 0.3s, transform 0.3s, visibility 0.3s, background 0.2s;
}
.back-top svg { width: 20px; height: 20px; }
.back-top.visible { opacity: 1; visibility: visible; transform: none; }
.back-top:hover { background: var(--red-dark); }

/* ===== 灯箱 ===== */
.lightbox {
  position: fixed; inset: 0; z-index: 300;
  background: rgba(10, 11, 14, 0.92);
  display: grid; place-items: center; padding: 4vmin;
  animation: lb-in 0.25s var(--ease);
}
.lightbox[hidden] { display: none; }
.lightbox img {
  max-width: 90vw; max-height: 86vh; border-radius: 10px;
  box-shadow: 0 30px 80px rgba(0, 0, 0, 0.6);
}
.lb-close, .lb-prev, .lb-next {
  position: absolute; background: rgba(255, 255, 255, 0.1); color: #fff;
  border: 0; border-radius: 50%; display: grid; place-items: center;
  transition: background 0.2s;
}
.lb-close { top: 20px; right: 20px; width: 46px; height: 46px; font-size: 26px; }
.lb-prev { left: 16px; top: 50%; transform: translateY(-50%); width: 48px; height: 48px; font-size: 30px; }
.lb-next { right: 16px; top: 50%; transform: translateY(-50%); width: 48px; height: 48px; font-size: 30px; }
.lb-close:hover, .lb-prev:hover, .lb-next:hover { background: var(--red); }
@keyframes lb-in { from { opacity: 0; } to { opacity: 1; } }

/* ===== 滚动显现动画 ===== */
.reveal { opacity: 0; transform: translateY(26px); transition: opacity 0.7s var(--ease), transform 0.7s var(--ease); }
.reveal[data-delay="1"] { transition-delay: 0.12s; }
.reveal[data-delay="2"] { transition-delay: 0.24s; }
.reveal[data-delay="3"] { transition-delay: 0.36s; }
.reveal[data-delay="4"] { transition-delay: 0.48s; }
.reveal.visible { opacity: 1; transform: none; }

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .reveal { opacity: 1; transform: none; transition: none; }
  .lightbox { animation: none; }
  * { transition-duration: 0.01ms !important; animation-duration: 0.01ms !important; }
}

/* ==========================================================================
   响应式
   ========================================================================== */
@media (max-width: 960px) {
  .grid-2 { gap: 44px; }
  .grid-3 { grid-template-columns: 1fr; }
  .usp-bar { grid-template-columns: repeat(2, 1fr); }
  .usp:nth-child(3)::before { display: none; }
  .gallery-grid { grid-template-columns: repeat(2, 1fr); }
  .fleet-media { order: -1; }
}

@media (max-width: 820px) {
  .section { padding: 68px 0; }
  .grid-2 { grid-template-columns: 1fr; }
  .about-media { padding-bottom: 0; }
  .about-media .photo-sm { position: static; width: 62%; margin: -60px 0 0 auto; }
  .header-cta { display: none; }

  /* 移动端抽屉导航 */
  .nav-toggle { display: flex; }
  .site-nav {
    position: fixed; top: var(--header-h); left: 0; right: 0; z-index: 99;
    background: rgba(255, 255, 255, 0.98);
    backdrop-filter: blur(16px); -webkit-backdrop-filter: blur(16px);
    border-bottom: 1px solid var(--line);
    max-height: 0; overflow: hidden;
    transition: max-height 0.4s var(--ease);
  }
  .site-nav.open { max-height: 420px; box-shadow: 0 24px 40px rgba(22, 24, 29, 0.12); }
  .site-nav ul { flex-direction: column; gap: 2px; padding: 12px 5%; }
  .site-nav a { padding: 13px 16px; font-size: 16px; border-radius: 10px; }

  .hero { text-align: left; }
  .hero-stats { grid-template-columns: repeat(4, 1fr); gap: 6px; }
  .hero-actions .btn { flex: 1; min-width: 140px; }
}

@media (max-width: 560px) {
  body { font-size: 15px; }
  .brand-en { display: none; }
  .hero { min-height: 92svh; }
  .hero-stats { grid-template-columns: repeat(2, 1fr); gap: 20px 8px; }
  .gallery-grid { grid-template-columns: 1fr; gap: 14px; }
  .gallery-grid img { aspect-ratio: 4 / 3; }
  .usp-bar { grid-template-columns: 1fr; }
  .usp + .usp::before { display: none; }
  .usp + .usp { border-top: 1px solid rgba(255, 255, 255, 0.1); }
  .contact-form { padding: 28px 20px; }
  .footer-inner { grid-template-columns: 1fr; }
  .photo-sm { width: 74%; }
  .lb-prev { left: 8px; }
  .lb-next { right: 8px; }
}