/* =========================================================
   深圳市大唐志业科技有限公司 官网样式
   风格：天空蓝 / 云白 / 企业科技 · 简洁专业
   ========================================================= */

/* ---------- 变量 ---------- */
:root {
  /* 配色 */
  --bg:        #edf5fd;            /* 页面天空蓝浅底 */
  --bg-deep:   #e2eefb;            /* 区块深一档蓝 */
  --card:      #ffffff;            /* 卡片云白 */
  --ink:       #12324a;            /* 主文字深蓝墨 */
  --ink-soft:  #4d6c85;            /* 次要文字 */
  --ink-faint: #8ea9bf;            /* 弱化文字 */
  --sky:       #2f8fdd;            /* 主强调 · 天空蓝 */
  --sky-deep:  #1069b4;            /* 强调深 */
  --sky-soft:  #a9d5f5;            /* 强调浅 */
  --sky-mist:  #e6f2fd;            /* 强调雾面 */
  --line:      #d3e6f6;            /* 分割线 */
  --ok:        #1f8a5b;            /* 成功提示 */

  /* 字体 */
  --font-head: "PingFang SC", "HarmonyOS Sans SC", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  --font-sans: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;

  /* 布局 */
  --container: 1160px;
  --radius: 14px;
  --shadow:    0 16px 44px rgba(31, 96, 150, .12);
  --shadow-sm: 0 8px 22px rgba(31, 96, 150, .09);
  --header-h: 72px;
}

/* ---------- 基础 ---------- */
* { margin: 0; padding: 0; box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  font-family: var(--font-sans);
  color: var(--ink);
  background: var(--bg);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

img { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }
ul { list-style: none; }

button { font-family: inherit; }

:focus-visible {
  outline: 2px solid var(--sky-deep);
  outline-offset: 3px;
  border-radius: 4px;
}

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

.section { padding: 96px 0; scroll-margin-top: calc(var(--header-h) + 8px); }
.section:nth-of-type(even) { background: var(--bg-deep); }

/* ---------- 区块标题 ---------- */
.section-head { text-align: center; max-width: 660px; margin: 0 auto 56px; }

.section-kicker {
  font-family: var(--font-head);
  letter-spacing: .3em;
  text-transform: uppercase;
  font-size: 12.5px;
  font-weight: 600;
  color: var(--sky);
  margin-bottom: 10px;
}

.section-title {
  font-family: var(--font-head);
  font-size: clamp(26px, 3.6vw, 38px);
  font-weight: 700;
  letter-spacing: .02em;
}

.section-title::after {
  content: "";
  display: block;
  width: 52px;
  height: 4px;
  background: linear-gradient(90deg, var(--sky), var(--sky-soft));
  margin: 16px auto 0;
  border-radius: 4px;
}

.section-desc { margin-top: 18px; color: var(--ink-soft); font-size: 15px; }

/* =========================================================
   顶部导航
   ========================================================= */
.site-header {
  position: fixed;
  inset: 0 0 auto 0;
  z-index: 100;
  background: rgba(255, 255, 255, .78);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border-bottom: 1px solid transparent;
  transition: box-shadow .3s ease, border-color .3s ease, background .3s ease;
}

/* 顶部品牌色细条 */
.site-header::before {
  content: "";
  position: absolute;
  inset: 0 0 auto 0;
  height: 3px;
  background: linear-gradient(90deg, var(--sky-deep), var(--sky), #7cc4f5, var(--sky));
}

.site-header.scrolled {
  box-shadow: var(--shadow-sm);
  border-bottom-color: var(--line);
  background: rgba(255, 255, 255, .94);
}

.nav-wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  height: var(--header-h);
}

.brand { display: flex; align-items: center; gap: 12px; min-width: 0; }

.brand-mark {
  display: grid;
  place-items: center;
  width: 42px;
  height: 42px;
  flex: 0 0 42px;
  border-radius: 11px;
  background: linear-gradient(135deg, #4aa7f0, var(--sky-deep));
  color: #fff;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: 15px;
  letter-spacing: .04em;
  box-shadow: 0 6px 16px rgba(47, 143, 221, .38);
}

.brand-text {
  font-family: var(--font-head);
  font-size: 17px;
  font-weight: 700;
  letter-spacing: .02em;
  color: var(--ink);
  white-space: nowrap;
}
.brand-short { display: none; }

.nav { display: flex; align-items: center; gap: 28px; }

.nav-link {
  position: relative;
  font-size: 15px;
  color: var(--ink-soft);
  padding: 6px 2px;
  white-space: nowrap;
  transition: color .25s ease;
}

.nav-link::after {
  content: "";
  position: absolute;
  left: 0; right: 100%;
  bottom: 0;
  height: 2px;
  background: var(--sky);
  border-radius: 2px;
  transition: right .28s ease;
}

.nav-link:hover, .nav-link.active { color: var(--sky-deep); }
.nav-link:hover::after, .nav-link.active::after { right: 0; }

.nav-link.nav-cta {
  color: #fff;
  background: linear-gradient(135deg, var(--sky), var(--sky-deep));
  padding: 9px 22px;
  border-radius: 999px;
  box-shadow: 0 6px 16px rgba(47, 143, 221, .34);
  transition: transform .25s ease, box-shadow .25s ease, filter .25s ease;
}
.nav-link.nav-cta::after { display: none; }
.nav-link.nav-cta:hover {
  transform: translateY(-1px);
  color: #fff;
  filter: brightness(1.06);
  box-shadow: 0 10px 22px rgba(47, 143, 221, .42);
}

/* 移动端汉堡 */
.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 44px;
  height: 44px;
  padding: 0 10px;
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 10px;
  cursor: pointer;
}
.nav-toggle span {
  display: block;
  height: 2px;
  background: var(--ink);
  border-radius: 2px;
  transition: transform .3s ease, opacity .3s ease;
}
.nav-toggle.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-toggle.open span:nth-child(2) { opacity: 0; }
.nav-toggle.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* =========================================================
   Hero 首屏 · 天空
   ========================================================= */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  overflow: hidden;
  padding: calc(var(--header-h) + 72px) 0 96px;
  scroll-margin-top: var(--header-h);
}

/* 天空渐变 + 云层 + 淡网格 */
.hero-bg {
  position: absolute;
  inset: 0;
  z-index: 0;
  background:
    radial-gradient(1100px 620px at 50% -10%, #ffffff 0%, rgba(255, 255, 255, 0) 58%),
    radial-gradient(760px 420px at 88% 14%, rgba(255, 255, 255, .8), transparent 62%),
    radial-gradient(620px 400px at 6% 78%, rgba(47, 143, 221, .22), transparent 66%),
    linear-gradient(180deg, #b9ddf8 0%, #d5ebfc 32%, #e9f4fe 64%, var(--bg) 100%);
}

.hero-bg::before {
  content: "";
  position: absolute;
  left: -10%; right: -10%; bottom: -8%;
  height: 56%;
  background:
    radial-gradient(ellipse at 18% 100%, rgba(255, 255, 255, .95), rgba(255, 255, 255, 0) 62%),
    radial-gradient(ellipse at 62% 106%, rgba(255, 255, 255, .9), rgba(255, 255, 255, 0) 60%),
    radial-gradient(ellipse at 96% 98%, rgba(255, 255, 255, .85), rgba(255, 255, 255, 0) 58%);
}

.hero-bg::after {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(47, 143, 221, .07) 1px, transparent 1px),
    linear-gradient(90deg, rgba(47, 143, 221, .07) 1px, transparent 1px);
  background-size: 64px 64px;
  mask-image: radial-gradient(circle at 50% 42%, #000 18%, transparent 70%);
  -webkit-mask-image: radial-gradient(circle at 50% 42%, #000 18%, transparent 70%);
}

.hero-inner { position: relative; z-index: 1; text-align: center; }

.hero-kicker {
  display: inline-block;
  font-family: var(--font-head);
  font-weight: 600;
  letter-spacing: .18em;
  font-size: 13.5px;
  color: var(--sky-deep);
  padding: 8px 22px;
  border: 1px solid rgba(47, 143, 221, .35);
  border-radius: 999px;
  background: rgba(255, 255, 255, .78);
  box-shadow: 0 4px 14px rgba(31, 96, 150, .08);
}

.hero-title {
  font-family: var(--font-head);
  font-size: clamp(32px, 5.6vw, 58px);
  line-height: 1.24;
  font-weight: 700;
  letter-spacing: .01em;
  margin: 26px 0 22px;
  color: #0f2d44;
}
.hero-title .accent {
  position: relative;
  color: var(--sky-deep);
  white-space: nowrap;
}
.hero-title .accent::after {
  content: "";
  position: absolute;
  left: -2px; right: -2px;
  bottom: 6px;
  height: 12px;
  background: rgba(169, 213, 245, .7);
  z-index: -1;
  border-radius: 4px;
}

.hero-sub {
  max-width: 640px;
  margin: 0 auto;
  color: var(--ink-soft);
  font-size: 16px;
}

.hero-actions { margin-top: 38px; display: flex; gap: 16px; justify-content: center; flex-wrap: wrap; }

.btn {
  display: inline-block;
  font-size: 15px;
  font-weight: 600;
  padding: 13px 32px;
  border-radius: 999px;
  border: 1px solid transparent;
  cursor: pointer;
  transition: transform .25s ease, box-shadow .25s ease, background .25s ease, color .25s ease;
}
.btn-primary {
  background: linear-gradient(135deg, var(--sky), var(--sky-deep));
  color: #fff;
  box-shadow: 0 12px 26px rgba(47, 143, 221, .38);
}
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 16px 32px rgba(47, 143, 221, .46); }
.btn-ghost {
  background: rgba(255, 255, 255, .8);
  color: var(--sky-deep);
  border-color: rgba(47, 143, 221, .45);
}
.btn-ghost:hover { background: #fff; border-color: var(--sky); transform: translateY(-2px); }

/* Hero 数据 */
.hero-stats {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
  max-width: 780px;
  margin: 62px auto 0;
  padding: 28px 18px;
  background: rgba(255, 255, 255, .86);
  backdrop-filter: blur(6px);
  -webkit-backdrop-filter: blur(6px);
  border: 1px solid rgba(255, 255, 255, .9);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}
.stat { text-align: center; }
.stat + .stat { border-left: 1px solid var(--line); }
.stat-num {
  font-family: var(--font-head);
  font-size: clamp(24px, 3.6vw, 36px);
  font-weight: 700;
  color: var(--sky-deep);
  letter-spacing: .01em;
}
.stat-label { font-size: 13px; color: var(--ink-soft); margin-top: 2px; }

/* =========================================================
   服务项目
   ========================================================= */
.service-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.service-card {
  position: relative;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 30px 26px 26px;
  box-shadow: var(--shadow-sm);
  transition: transform .3s ease, box-shadow .3s ease, border-color .3s ease;
  display: flex;
  flex-direction: column;
  overflow: hidden;
}
.service-card::before {
  content: "";
  position: absolute;
  inset: 0 0 auto 0;
  height: 3px;
  background: linear-gradient(90deg, var(--sky), var(--sky-soft));
  transform: scaleX(0);
  transform-origin: left;
  transition: transform .35s ease;
}
.service-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow);
  border-color: var(--sky-soft);
}
.service-card:hover::before { transform: scaleX(1); }

.service-icon {
  width: 58px;
  height: 58px;
  border-radius: 14px;
  display: grid;
  place-items: center;
  color: var(--sky-deep);
  background: linear-gradient(180deg, #eaf5ff, #d6eafb);
  border: 1px solid rgba(47, 143, 221, .16);
  margin-bottom: 20px;
}
.service-icon svg { width: 32px; height: 32px; }

.service-name {
  font-family: var(--font-head);
  font-size: 19px;
  font-weight: 700;
  letter-spacing: .01em;
  margin-bottom: 10px;
}
.service-desc { font-size: 14px; color: var(--ink-soft); flex: 1; }

.service-more {
  display: inline-block;
  margin-top: 18px;
  font-size: 14px;
  color: var(--sky-deep);
  font-weight: 600;
  transition: letter-spacing .25s ease;
}
.service-more:hover { letter-spacing: .05em; }

/* =========================================================
   案例展示
   ========================================================= */
.case-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
}

.case-card {
  position: relative;
  display: flex;
  flex-direction: column;
  padding: 34px 30px;
  background: var(--card);
  border: 1px solid var(--line);
  border-left: 4px solid var(--sky);
  border-radius: var(--radius);
  box-shadow: var(--shadow-sm);
  transition: transform .3s ease, box-shadow .3s ease, border-color .3s ease;
  overflow: hidden;
}
a.case-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow);
  border-left-color: var(--sky-deep);
}

.case-tag {
  position: absolute;
  top: 18px;
  right: 18px;
  font-size: 12px;
  color: var(--sky-deep);
  border: 1px solid var(--sky-soft);
  padding: 3px 12px;
  border-radius: 999px;
  background: var(--sky-mist);
}

.case-name {
  font-family: var(--font-head);
  font-size: 21px;
  font-weight: 700;
  letter-spacing: .01em;
  margin: 6px 0 10px;
}

.case-desc { font-size: 14px; color: var(--ink-soft); }

.case-link {
  margin-top: 18px;
  font-size: 14px;
  font-weight: 600;
  color: var(--sky-deep);
  transition: letter-spacing .25s ease;
}
a.case-card:hover .case-link { letter-spacing: .05em; }

/* 小程序扫码体验 */
.case-scan {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-top: 20px;
  padding-top: 20px;
  border-top: 1px dashed var(--line);
}

.case-qr {
  flex: 0 0 auto;
  padding: 6px;
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 10px;
  cursor: zoom-in;
  line-height: 0;
  box-shadow: var(--shadow-sm);
  transition: transform .25s ease, border-color .25s ease, box-shadow .25s ease;
}
.case-qr:hover {
  transform: translateY(-2px);
  border-color: var(--sky-soft);
  box-shadow: var(--shadow);
}
.case-qr img { width: 116px; height: 116px; border-radius: 4px; }

.case-scan-text strong {
  display: block;
  font-size: 14px;
  color: var(--sky-deep);
  margin-bottom: 4px;
}
.case-scan-text span { font-size: 12.5px; color: var(--ink-faint); line-height: 1.6; }

/* 二维码放大弹层 */
.qr-modal {
  position: fixed;
  inset: 0;
  z-index: 200;
  display: grid;
  place-items: center;
  padding: 24px;
  background: rgba(12, 40, 62, .62);
  backdrop-filter: blur(4px);
  -webkit-backdrop-filter: blur(4px);
  animation: qrFade .25s ease;
}
.qr-modal[hidden] { display: none; }

@keyframes qrFade { from { opacity: 0; } to { opacity: 1; } }

.qr-modal-box {
  position: relative;
  text-align: center;
  padding: 26px 26px 22px;
  background: #fff;
  border-radius: 16px;
  box-shadow: 0 24px 60px rgba(10, 40, 66, .32);
  animation: qrPop .28s ease;
}
@keyframes qrPop { from { opacity: 0; transform: translateY(12px) scale(.97); } to { opacity: 1; transform: none; } }

.qr-modal-box img { width: 252px; height: 252px; border-radius: 10px; }
.qr-modal-title { margin-top: 14px; font-family: var(--font-head); font-weight: 700; font-size: 16px; }
.qr-modal-tip { margin-top: 4px; font-size: 13px; color: var(--ink-soft); }

.qr-modal-close {
  position: absolute;
  top: 10px;
  right: 12px;
  width: 32px;
  height: 32px;
  border: none;
  border-radius: 50%;
  background: var(--sky-mist);
  color: var(--sky-deep);
  font-size: 20px;
  line-height: 1;
  cursor: pointer;
  transition: background .25s ease, color .25s ease;
}
.qr-modal-close:hover { background: var(--sky); color: #fff; }

/* =========================================================
   技术能力
   ========================================================= */
.skill-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.skill-block {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 30px 28px;
  box-shadow: var(--shadow-sm);
  transition: transform .3s ease, box-shadow .3s ease;
}
.skill-block:hover { transform: translateY(-4px); box-shadow: var(--shadow); }

.skill-cat {
  font-family: var(--font-head);
  font-size: 18px;
  font-weight: 700;
  letter-spacing: .02em;
  padding-bottom: 14px;
  margin-bottom: 14px;
  border-bottom: 2px solid var(--sky-soft);
  color: var(--sky-deep);
}

.skill-list li {
  position: relative;
  padding: 6px 0 6px 22px;
  font-size: 14.5px;
  color: var(--ink-soft);
}
.skill-list li::before {
  content: "";
  position: absolute;
  left: 2px;
  top: 15px;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--sky);
  opacity: .5;
}

/* =========================================================
   关于我们
   ========================================================= */
.about-inner {
  display: grid;
  grid-template-columns: 1fr 1.15fr;
  gap: 48px;
  align-items: center;
}

.about-ornament {
  font-family: var(--font-head);
  font-size: clamp(90px, 13vw, 168px);
  font-weight: 700;
  line-height: 1;
  color: rgba(47, 143, 221, .13);
  letter-spacing: .06em;
  user-select: none;
  text-align: center;
}

.about-body .section-kicker, .about-body .section-title { text-align: left; }
.about-body .section-title::after { margin-left: 0; }

.about-text { margin-top: 18px; color: var(--ink-soft); font-size: 15px; }
.about-text strong { color: var(--sky-deep); }

.about-points { margin-top: 22px; }
.about-points li {
  position: relative;
  padding: 8px 0 8px 26px;
  font-size: 14.5px;
  color: var(--ink);
}
.about-points li::before {
  content: "✓";
  position: absolute;
  left: 0;
  color: var(--sky);
  font-weight: 700;
}

/* =========================================================
   联系方式
   ========================================================= */
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1.05fr;
  gap: 40px;
  align-items: start;
}

.contact-info {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 30px 28px;
  box-shadow: var(--shadow-sm);
}

.contact-title {
  font-family: var(--font-head);
  font-size: 18px;
  font-weight: 700;
  letter-spacing: .02em;
  color: var(--sky-deep);
  padding-bottom: 14px;
  margin-bottom: 6px;
  border-bottom: 2px solid var(--sky-soft);
}

.contact-item {
  display: flex;
  align-items: center;
  gap: 16px;
  padding: 18px 0;
  border-bottom: 1px dashed var(--line);
}
.contact-item:last-of-type { border-bottom: none; }
.contact-label {
  flex: 0 0 96px;
  font-family: var(--font-head);
  font-size: 14.5px;
  color: var(--sky-deep);
  font-weight: 600;
}
.contact-value { font-size: 15px; }
a.contact-value {
  color: var(--sky-deep);
  border-bottom: 1px dashed rgba(47, 143, 221, .5);
  transition: border-color .25s ease;
}
a.contact-value:hover { border-color: var(--sky-deep); }

.contact-tip { margin-top: 18px; font-size: 12.5px; color: var(--ink-faint); }

.contact-form {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 30px 28px;
  box-shadow: var(--shadow-sm);
}

.form-row { margin-bottom: 16px; }

.contact-form input,
.contact-form select,
.contact-form textarea {
  width: 100%;
  padding: 12px 14px;
  font-family: inherit;
  font-size: 14.5px;
  color: var(--ink);
  background: #f7fbff;
  border: 1px solid var(--line);
  border-radius: 10px;
  outline: none;
  transition: border-color .25s ease, box-shadow .25s ease, background .25s ease;
}
.contact-form textarea { resize: vertical; }
.contact-form input::placeholder,
.contact-form textarea::placeholder { color: var(--ink-faint); }

.contact-form input:focus,
.contact-form select:focus,
.contact-form textarea:focus {
  background: #fff;
  border-color: var(--sky);
  box-shadow: 0 0 0 3px rgba(47, 143, 221, .18);
}

.btn-block { width: 100%; }
.form-note { margin-top: 12px; text-align: center; font-size: 12.5px; color: var(--ink-faint); }
.form-note.success { color: var(--ok); }

/* =========================================================
   页脚
   ========================================================= */
.site-footer {
  background: linear-gradient(180deg, #10314d, #0b2437);
  color: #b7d2e8;
  padding: 34px 0;
  font-size: 13.5px;
}
.footer-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 14px;
}
.footer-brand { display: flex; align-items: center; gap: 12px; }
.site-footer .brand-mark { box-shadow: none; }

.footer-meta { text-align: right; }
.footer-copy { color: #8fb0c9; }

.footer-icp { margin-top: 4px; font-size: 12.5px; }
.footer-icp a {
  color: #8fb0c9;
  transition: color .25s ease;
}
.footer-icp a:hover { color: #d6e8f7; text-decoration: underline; }

/* ---------- 回到顶部 ---------- */
.back-top {
  position: fixed;
  right: 26px;
  bottom: 26px;
  z-index: 90;
  width: 46px;
  height: 46px;
  border: none;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--sky), var(--sky-deep));
  color: #fff;
  cursor: pointer;
  display: grid;
  place-items: center;
  box-shadow: 0 10px 24px rgba(47, 143, 221, .42);
  opacity: 0;
  visibility: hidden;
  transform: translateY(12px);
  transition: opacity .3s ease, transform .3s ease, visibility .3s ease, filter .25s ease;
}
.back-top.show { opacity: 1; visibility: visible; transform: translateY(0); }
.back-top:hover { filter: brightness(1.08); }
.back-top svg { width: 20px; height: 20px; }

/* =========================================================
   滚动渐显动画
   ========================================================= */
.reveal {
  opacity: 0;
  transform: translateY(26px);
  transition: opacity .7s ease, transform .7s ease;
}
.reveal.visible {
  opacity: 1;
  transform: none;
}

/* =========================================================
   响应式
   ========================================================= */
@media (max-width: 1080px) {
  .brand-full { display: none; }
  .brand-short { display: inline; }
  .nav { gap: 20px; }
}

@media (max-width: 900px) {
  .section { padding: 72px 0; }

  .nav {
    position: fixed;
    top: var(--header-h);
    left: 0; right: 0;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    background: rgba(255, 255, 255, .98);
    border-bottom: 1px solid var(--line);
    box-shadow: var(--shadow-sm);
    padding: 12px 24px 20px;
    transform: translateY(-12px);
    opacity: 0;
    visibility: hidden;
    transition: transform .3s ease, opacity .3s ease, visibility .3s ease;
  }
  .nav.open { transform: none; opacity: 1; visibility: visible; }
  .nav-link { padding: 13px 4px; width: 100%; border-bottom: 1px solid var(--line); }
  .nav-link::after { display: none; }
  .nav-link.nav-cta { width: auto; align-self: flex-start; margin-top: 12px; }

  .nav-toggle { display: flex; }

  .service-grid, .skill-grid { grid-template-columns: repeat(2, 1fr); }
  .about-inner { grid-template-columns: 1fr; gap: 22px; }
  .about-ornament { font-size: 84px; }
  .about-body .section-kicker, .about-body .section-title { text-align: center; }
  .about-body .section-title::after { margin-left: auto; margin-right: auto; }
  .contact-grid { grid-template-columns: 1fr; }
  .hero-stats { grid-template-columns: repeat(2, 1fr); row-gap: 22px; }
  .stat:nth-child(3) { border-left: none; }
}

@media (max-width: 620px) {
  .container { padding: 0 18px; }
  .service-grid, .skill-grid, .case-grid { grid-template-columns: 1fr; }
  .hero { min-height: auto; padding: calc(var(--header-h) + 56px) 0 72px; }
  .hero-stats { padding: 22px 14px; }
  .case-card { padding: 28px 22px; }

  /* 窄屏下联系方式改为上下排布，避免长公司名挤压 */
  .contact-info, .contact-form { padding: 24px 20px; }
  .contact-item { display: block; padding: 14px 0; }
  .contact-label { display: block; margin-bottom: 2px; }
  .contact-value { word-break: break-word; }

  .footer-inner { flex-direction: column; text-align: center; }
  .footer-brand { flex-direction: column; gap: 10px; }
  .footer-meta { text-align: center; }
}

/* ---------- 降低动效偏好 ---------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .reveal { opacity: 1; transform: none; transition: none; }
  * { animation-duration: .001ms !important; transition-duration: .001ms !important; }
}