:root {
  --blue-950: #061526;
  --blue-900: #0a2744;
  --blue-800: #0f3a66;
  --blue-700: #165088;
  --blue-600: #1a6bb5;
  --blue-500: #2b85d4;
  --blue-100: #dceaf7;
  --ink: #0f1c2e;
  --ink-soft: #3d4f66;
  --ink-muted: #6b7c90;
  --paper: #f7fafd;
  --white: #ffffff;
  --line: rgba(15, 28, 46, 0.12);
  --header-h: 72px;
  --ease: cubic-bezier(0.22, 1, 0.36, 1);
  --font-display: 'Noto Serif SC', 'Songti SC', serif;
  --font-body: 'Noto Sans SC', 'PingFang SC', sans-serif;
  --pad: clamp(1.25rem, 4vw, 4.5rem);
}

*, *::before, *::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-body);
  background: var(--paper);
  color: var(--ink);
  line-height: 1.7;
  overflow-x: hidden;
}

a {
  color: inherit;
  text-decoration: none;
}

/* —— 顶栏 —— */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  height: var(--header-h);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 var(--pad);
  transition: background 0.35s var(--ease), color 0.35s var(--ease), box-shadow 0.35s var(--ease);
  color: var(--white);
}

.site-header.is-scrolled {
  background: rgba(247, 250, 253, 0.92);
  color: var(--ink);
  backdrop-filter: blur(12px);
  box-shadow: 0 1px 0 var(--line);
}

.site-logo {
  font-family: var(--font-display);
  font-weight: 900;
  font-size: 1.35rem;
  letter-spacing: 0.18em;
}

.site-nav {
  display: flex;
  gap: 2rem;
}

.site-nav a {
  font-size: 0.88rem;
  letter-spacing: 0.08em;
  opacity: 0.55;
  transition: opacity 0.3s var(--ease);
}

.site-nav a:hover,
.site-nav a.active {
  opacity: 1;
}

.menu-toggle {
  display: none;
  width: 40px;
  height: 40px;
  border: none;
  background: transparent;
  flex-direction: column;
  justify-content: center;
  gap: 7px;
  cursor: pointer;
  padding: 0;
}

.menu-toggle span {
  display: block;
  width: 22px;
  height: 2px;
  background: currentColor;
  transition: transform 0.3s var(--ease), opacity 0.3s var(--ease);
}

.menu-toggle[aria-expanded="true"] span:first-child {
  transform: translateY(4.5px) rotate(45deg);
}

.menu-toggle[aria-expanded="true"] span:last-child {
  transform: translateY(-4.5px) rotate(-45deg);
}

/* —— 首屏 —— */
.hero {
  position: relative;
  min-height: 100vh;
  min-height: 100dvh;
  display: flex;
  align-items: flex-end;
  overflow: hidden;
  background: var(--blue-950);
  color: var(--white);
  padding: calc(var(--header-h) + 2rem) var(--pad) clamp(3rem, 8vh, 5.5rem);
}

.hero-plane {
  position: absolute;
  inset: 0;
  background:
    linear-gradient(145deg, var(--blue-950) 0%, var(--blue-900) 38%, var(--blue-700) 100%);
  animation: plane-in 1.4s var(--ease) both;
}

.hero-plane::after {
  content: '';
  position: absolute;
  width: 70vmax;
  height: 70vmax;
  right: -18%;
  bottom: -35%;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(43, 133, 212, 0.45) 0%, transparent 68%);
  animation: bloom 1.8s 0.2s var(--ease) both;
}

.hero-grid {
  position: absolute;
  inset: 0;
  opacity: 0.22;
  background-image:
    linear-gradient(rgba(255, 255, 255, 0.07) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255, 255, 255, 0.07) 1px, transparent 1px);
  background-size: 64px 64px;
  mask-image: linear-gradient(180deg, transparent, #000 30%, #000 70%, transparent);
  animation: grid-fade 1.2s 0.3s var(--ease) both;
}

.hero-body {
  position: relative;
  z-index: 1;
  max-width: 52rem;
}

.hero-brand {
  font-family: var(--font-display);
  font-size: clamp(3.2rem, 12vw, 7.5rem);
  font-weight: 900;
  line-height: 0.95;
  letter-spacing: 0.08em;
  margin-bottom: 1.5rem;
  animation: rise 0.9s 0.15s var(--ease) both;
}

.hero-title {
  font-family: var(--font-display);
  font-size: clamp(1.2rem, 2.6vw, 1.75rem);
  font-weight: 700;
  line-height: 1.45;
  margin-bottom: 0.85rem;
  animation: rise 0.9s 0.28s var(--ease) both;
}

.hero-desc {
  max-width: 28rem;
  color: rgba(255, 255, 255, 0.72);
  margin-bottom: 2rem;
  animation: rise 0.9s 0.4s var(--ease) both;
}

.hero-body .btn {
  animation: rise 0.9s 0.52s var(--ease) both;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.95rem 1.75rem;
  font-family: inherit;
  font-size: 0.92rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  border: 1px solid rgba(255, 255, 255, 0.55);
  background: transparent;
  color: var(--white);
  cursor: pointer;
  transition: background 0.3s var(--ease), color 0.3s var(--ease), border-color 0.3s var(--ease), transform 0.3s var(--ease);
}

.btn:hover {
  background: var(--white);
  color: var(--blue-900);
  transform: translateY(-2px);
}

.btn-solid {
  border-color: var(--blue-600);
  background: var(--blue-600);
  color: var(--white);
}

.btn-solid:hover {
  background: var(--blue-700);
  border-color: var(--blue-700);
  color: var(--white);
}

/* —— 关于：大字编辑式 —— */
.about {
  background: var(--white);
  padding: clamp(5rem, 12vh, 8.5rem) var(--pad);
}

.about-frame {
  max-width: 58rem;
  margin: 0 auto;
  border-left: 3px solid var(--blue-600);
  padding-left: clamp(1.25rem, 3vw, 2.5rem);
}

.about-kicker {
  font-size: 0.78rem;
  letter-spacing: 0.28em;
  color: var(--blue-600);
  font-weight: 600;
  margin-bottom: 1.25rem;
}

.about-heading {
  font-family: var(--font-display);
  font-size: clamp(1.85rem, 4.2vw, 3.1rem);
  font-weight: 700;
  line-height: 1.35;
  color: var(--ink);
  margin-bottom: 2.5rem;
}

.about-copy {
  display: grid;
  gap: 1.25rem;
  max-width: 40rem;
}

.about-copy p {
  color: var(--ink-soft);
  font-size: 1.05rem;
}

/* —— 业务：纵向通栏列表 —— */
.services {
  background: var(--blue-900);
  color: var(--white);
  padding: clamp(4.5rem, 10vh, 7rem) 0;
}

.services-intro {
  padding: 0 var(--pad) 2.5rem;
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 1.5rem;
  flex-wrap: wrap;
}

.services-intro h2 {
  font-family: var(--font-display);
  font-size: clamp(1.7rem, 3.5vw, 2.4rem);
  font-weight: 700;
}

.services-intro p {
  color: rgba(255, 255, 255, 0.55);
  font-size: 0.95rem;
}

.services-list {
  list-style: none;
  border-top: 1px solid rgba(255, 255, 255, 0.12);
}

.service-row {
  display: grid;
  grid-template-columns: 5.5rem 1fr;
  gap: clamp(1rem, 3vw, 3rem);
  align-items: start;
  padding: clamp(1.75rem, 3.5vh, 2.75rem) var(--pad);
  border-bottom: 1px solid rgba(255, 255, 255, 0.12);
  transition: background 0.35s var(--ease);
}

.service-row:hover {
  background: rgba(43, 133, 212, 0.12);
}

.service-num {
  font-family: var(--font-display);
  font-size: clamp(1.5rem, 3vw, 2rem);
  color: var(--blue-500);
  line-height: 1.2;
}

.service-text h3 {
  font-family: var(--font-display);
  font-size: clamp(1.35rem, 2.5vw, 1.85rem);
  font-weight: 700;
  margin-bottom: 0.55rem;
}

.service-text p {
  max-width: 36rem;
  color: rgba(255, 255, 255, 0.68);
  font-size: 0.98rem;
}

/* —— 企信：左右分栏 —— */
.company {
  display: grid;
  grid-template-columns: minmax(12rem, 0.35fr) 1fr;
  gap: clamp(2rem, 5vw, 5rem);
  padding: clamp(5rem, 11vh, 8rem) var(--pad);
  background: var(--paper);
}

.company-side h2 {
  font-family: var(--font-display);
  font-size: clamp(1.7rem, 3.2vw, 2.3rem);
  margin-bottom: 0.65rem;
}

.company-side p {
  color: var(--ink-soft);
}

.company-list {
  display: flex;
  flex-direction: column;
}

.company-list > div {
  display: grid;
  grid-template-columns: minmax(7rem, 10rem) 1fr;
  gap: 1rem 1.5rem;
  padding: 1.35rem 0;
  border-bottom: 1px solid var(--line);
}

.company-list dt {
  font-size: 0.78rem;
  letter-spacing: 0.1em;
  color: var(--ink-muted);
  padding-top: 0.2rem;
}

.company-list dd {
  font-family: var(--font-display);
  font-size: 1.05rem;
  font-weight: 600;
  line-height: 1.55;
}

/* —— 联络：左右对位 —— */
.connect {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: clamp(2.5rem, 6vw, 5rem);
  align-items: start;
  padding: clamp(5rem, 11vh, 8rem) var(--pad);
  background: var(--white);
  border-top: 1px solid var(--line);
}

.connect-kicker {
  font-size: 0.78rem;
  letter-spacing: 0.28em;
  color: var(--blue-600);
  font-weight: 600;
  margin-bottom: 1rem;
}

.connect-title {
  font-family: var(--font-display);
  font-size: clamp(1.9rem, 4vw, 2.8rem);
  margin-bottom: 1.5rem;
}

.connect-email {
  display: inline-block;
  font-size: clamp(1.05rem, 2vw, 1.35rem);
  font-weight: 600;
  color: var(--blue-700);
  margin-bottom: 1.25rem;
  border-bottom: 1px solid transparent;
  transition: border-color 0.3s var(--ease);
}

.connect-email:hover {
  border-bottom-color: var(--blue-500);
}

.connect-address {
  color: var(--ink-soft);
  font-size: 0.95rem;
  line-height: 1.85;
}

.connect-form {
  display: flex;
  flex-direction: column;
  gap: 1.1rem;
}

.connect-form label {
  display: flex;
  flex-direction: column;
  gap: 0.45rem;
}

.connect-form label span {
  font-size: 0.78rem;
  letter-spacing: 0.08em;
  color: var(--ink-muted);
}

.connect-form input,
.connect-form textarea {
  width: 100%;
  padding: 0.9rem 0;
  border: none;
  border-bottom: 1px solid var(--line);
  background: transparent;
  color: var(--ink);
  font-family: inherit;
  font-size: 1rem;
  border-radius: 0;
  transition: border-color 0.3s var(--ease);
}

.connect-form input:focus,
.connect-form textarea:focus {
  outline: none;
  border-bottom-color: var(--blue-600);
}

.connect-form textarea {
  resize: vertical;
  min-height: 6rem;
}

.connect-form .btn {
  align-self: flex-start;
  margin-top: 0.5rem;
}

/* —— 页脚 —— */
.footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  flex-wrap: wrap;
  padding: 1.35rem var(--pad);
  background: var(--blue-950);
  color: rgba(255, 255, 255, 0.42);
  font-size: 0.85rem;
}

.footer a:hover {
  color: var(--blue-500);
}

/* Reveal */
.reveal {
  opacity: 0;
  transform: translateY(28px);
  transition: opacity 0.75s var(--ease), transform 0.75s var(--ease);
}

.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

@keyframes rise {
  from { opacity: 0; transform: translateY(28px); }
  to { opacity: 1; transform: translateY(0); }
}

@keyframes plane-in {
  from { opacity: 0; transform: scale(1.06); }
  to { opacity: 1; transform: scale(1); }
}

@keyframes bloom {
  from { opacity: 0; transform: scale(0.7); }
  to { opacity: 1; transform: scale(1); }
}

@keyframes grid-fade {
  from { opacity: 0; }
  to { opacity: 0.22; }
}

/* —— 响应式 —— */
@media (max-width: 900px) {
  .company {
    grid-template-columns: 1fr;
    gap: 2rem;
  }

  .connect {
    grid-template-columns: 1fr;
  }

  .service-row {
    grid-template-columns: 3.5rem 1fr;
  }
}

@media (max-width: 768px) {
  .site-nav {
    position: fixed;
    inset: var(--header-h) 0 auto 0;
    flex-direction: column;
    gap: 0;
    padding: 0.5rem var(--pad) 1.25rem;
    background: rgba(247, 250, 253, 0.97);
    color: var(--ink);
    border-bottom: 1px solid var(--line);
    transform: translateY(-120%);
    opacity: 0;
    pointer-events: none;
    transition: transform 0.35s var(--ease), opacity 0.35s var(--ease);
  }

  .site-nav.open {
    transform: translateY(0);
    opacity: 1;
    pointer-events: auto;
  }

  .site-nav a {
    padding: 0.85rem 0;
    opacity: 0.85;
    border-bottom: 1px solid var(--line);
  }

  .menu-toggle {
    display: flex;
  }

  .site-header:not(.is-scrolled) .site-nav.open {
    background: rgba(6, 21, 38, 0.96);
    color: var(--white);
    border-bottom-color: rgba(255, 255, 255, 0.1);
  }

  .site-header:not(.is-scrolled) .site-nav a {
    border-bottom-color: rgba(255, 255, 255, 0.1);
  }

  .company-list > div {
    grid-template-columns: 1fr;
    gap: 0.4rem;
  }
}