/* ==========================================
   盟众科技官网 · 全局样式
   设计规范：主色 #1a1a2e / 强调色 #e07a5f / 背景 #fafaf8
   移动端优先 + 响应式
   ========================================== */

/* ---- CSS Variables & Reset ---- */
:root {
  --deep: #1a1a2e;
  --warm: #e07a5f;
  --bg: #fafaf8;
  --text: #2d2d2d;
  --muted: #6b7280;
  --light: #f0f0ec;
  --white: #fff;
  --border: #e0e0d8;
  --radius: 8px;
  --shadow: 0 2px 20px rgba(0,0,0,.06);
  --transition: 0.25s ease;
}

/* ---- Global ---- */
html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* ---- Layout ---- */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

.section {
  padding: 5rem 0;
}

/* ---- Navigation ---- */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background: var(--deep);
  padding: 1rem 0;
  transition: background var(--transition);
}

.nav.scrolled {
  background: rgba(26,26,46,.95);
  backdrop-filter: blur(10px);
}

.nav .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.nav-logo {
  color: var(--white);
  font-size: 1.35rem;
  font-weight: 800;
  text-decoration: none;
  letter-spacing: 0.5px;
}

.nav-logo span {
  color: var(--warm);
}

.nav-links {
  display: flex;
  gap: 2rem;
  list-style: none;
}

.nav-links a {
  color: rgba(255,255,255,.8);
  text-decoration: none;
  font-weight: 500;
  font-size: 0.95rem;
  transition: color var(--transition);
  position: relative;
}

.nav-links a::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--warm);
  transition: width var(--transition);
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--warm);
}

.nav-links a:hover::after {
  width: 100%;
}

.menu-toggle {
  display: none;
  background: none;
  border: none;
  color: var(--white);
  font-size: 1.5rem;
  cursor: pointer;
  padding: 0.25rem;
}

/* ---- Buttons ---- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.85rem 2rem;
  border-radius: 6px;
  font-weight: 700;
  font-size: 1rem;
  text-decoration: none;
  cursor: pointer;
  border: none;
  transition: all var(--transition);
  white-space: nowrap;
  line-height: 1.4;
}

.btn-primary {
  background: var(--warm);
  color: var(--white);
}

.btn-primary:hover {
  background: #c96a4f;
  transform: translateY(-1px);
  box-shadow: 0 6px 20px rgba(224,122,95,.35);
}

.btn-outline {
  background: transparent;
  color: var(--white);
  border: 2px solid var(--white);
}

.btn-outline:hover {
  background: var(--white);
  color: var(--deep);
}

.btn-large {
  padding: 1rem 2.5rem;
  font-size: 1.1rem;
}

.btn-group {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
}

/* ---- Hero ---- */
.hero {
  background: var(--deep);
  color: var(--white);
  padding: 8rem 0 6rem;
  text-align: center;
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  top: -50%;
  left: -50%;
  width: 200%;
  height: 200%;
  background:
    radial-gradient(ellipse at 30% 20%, rgba(224,122,95,.08) 0%, transparent 60%),
    radial-gradient(ellipse at 70% 80%, rgba(224,122,95,.05) 0%, transparent 60%);
  pointer-events: none;
}

.hero h1 {
  font-size: clamp(2rem, 5vw, 3.25rem);
  font-weight: 900;
  line-height: 1.3;
  margin-bottom: 1.25rem;
  position: relative;
}

.hero .accent {
  color: var(--warm);
}

.hero p {
  font-size: clamp(1rem, 2vw, 1.2rem);
  color: rgba(255,255,255,.75);
  max-width: 700px;
  margin: 0 auto 2.5rem;
  position: relative;
}

.hero .btn-group {
  justify-content: center;
  position: relative;
}

/* ---- Section Headings ---- */
.section-title {
  font-size: clamp(1.6rem, 3.5vw, 2.25rem);
  font-weight: 900;
  text-align: center;
  margin-bottom: 0.75rem;
  color: var(--deep);
}

.section-sub {
  text-align: center;
  color: var(--muted);
  font-size: 1.05rem;
  margin-bottom: 3rem;
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
}

/* ---- Card Grid ---- */
.card-grid {
  display: grid;
  gap: 2rem;
}

.card-grid.three-col {
  grid-template-columns: repeat(3, 1fr);
}

/* ---- Scenario Cards ---- */
.card {
  background: var(--white);
  border-radius: 12px;
  padding: 2.5rem 2rem;
  border: 1px solid var(--border);
  transition: transform var(--transition), box-shadow var(--transition);
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: 0 8px 30px rgba(0,0,0,.08);
}

.card-icon {
  font-size: 2.5rem;
  margin-bottom: 1rem;
  display: block;
}

.card h3 {
  font-size: 1.25rem;
  font-weight: 800;
  margin-bottom: 0.75rem;
  color: var(--deep);
}

.card p {
  color: var(--muted);
  font-size: 0.95rem;
  line-height: 1.75;
  margin-bottom: 1.25rem;
}

.card-link {
  color: var(--warm);
  font-weight: 700;
  text-decoration: none;
  font-size: 0.95rem;
  transition: color var(--transition);
}

.card-link:hover {
  color: #c96a4f;
}

/* ---- Why Us ---- */
.why-us {
  background: var(--white);
}

.advantage-card {
  text-align: center;
  padding: 2.5rem 2rem;
  border-radius: 12px;
  background: var(--bg);
  border: 2px solid transparent;
  transition: border-color var(--transition), transform var(--transition);
}

.advantage-card:hover {
  border-color: var(--warm);
  transform: translateY(-3px);
}

.adv-icon {
  font-size: 2.5rem;
  margin-bottom: 1rem;
  display: block;
}

.advantage-card h3 {
  font-size: 1.2rem;
  font-weight: 800;
  margin-bottom: 0.75rem;
  color: var(--deep);
}

.advantage-card p {
  color: var(--muted);
  font-size: 0.95rem;
  line-height: 1.8;
}

/* ---- CTA Section ---- */
.cta {
  background: var(--deep);
  color: var(--white);
  text-align: center;
  position: relative;
  overflow: hidden;
}

.cta::before {
  content: '';
  position: absolute;
  top: -50%;
  left: -50%;
  width: 200%;
  height: 200%;
  background:
    radial-gradient(ellipse at 30% 50%, rgba(224,122,95,.1) 0%, transparent 50%),
    radial-gradient(ellipse at 70% 50%, rgba(224,122,95,.06) 0%, transparent 50%);
  pointer-events: none;
}

.cta h2 {
  font-size: clamp(1.5rem, 3vw, 2rem);
  font-weight: 900;
  margin-bottom: 1rem;
  position: relative;
}

.cta p {
  font-size: 1.05rem;
  color: rgba(255,255,255,.7);
  max-width: 650px;
  margin: 0 auto 2rem;
  position: relative;
  line-height: 1.8;
}

.cta .btn {
  position: relative;
}

/* ---- Footer ---- */
.footer {
  background: var(--deep);
  color: rgba(255,255,255,.7);
  padding: 3rem 0 1.5rem;
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.5fr 1fr 1.5fr;
  gap: 2rem;
  margin-bottom: 2rem;
}

.footer-col h4 {
  color: var(--white);
  font-size: 1.05rem;
  font-weight: 800;
  margin-bottom: 1rem;
}

.footer-col p {
  font-size: 0.9rem;
  line-height: 1.7;
  margin-bottom: 0.25rem;
}

.footer-tagline {
  margin-top: 0.75rem !important;
  color: var(--warm);
  font-weight: 500;
}

.footer-col ul {
  list-style: none;
  padding: 0;
}

.footer-col ul li {
  margin-bottom: 0.5rem;
}

.footer-col ul a {
  color: rgba(255,255,255,.7);
  text-decoration: none;
  font-size: 0.9rem;
  transition: color var(--transition);
}

.footer-col ul a:hover {
  color: var(--warm);
}

.tag-cloud {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.tag-cloud span {
  background: rgba(255,255,255,.08);
  color: rgba(255,255,255,.7);
  padding: 0.3rem 0.75rem;
  border-radius: 20px;
  font-size: 0.8rem;
}

.footer-bottom {
  border-top: 1px solid rgba(255,255,255,.1);
  padding-top: 1.5rem;
  text-align: center;
  font-size: 0.85rem;
}

/* ---- Page Header (subpages) ---- */
.page-header {
  background: var(--deep);
  color: var(--white);
  padding: 7rem 0 3rem;
  text-align: center;
}

.page-header h1 {
  font-size: clamp(1.8rem, 4vw, 2.6rem);
  font-weight: 900;
}

.page-header .accent {
  color: var(--warm);
}

.page-header p {
  color: rgba(255,255,255,.7);
  margin-top: 0.75rem;
  font-size: 1.05rem;
}

/* ---- Animations ---- */
.fade-in {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.fade-in.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ---- Mobile navigation ---- */
.nav-links.open {
  display: flex;
  flex-direction: column;
  position: absolute;
  top: 100%;
  left: 0;
  right: 0;
  background: var(--deep);
  padding: 1.5rem;
  gap: 1rem;
  border-top: 1px solid rgba(255,255,255,.1);
}

/* ==========================================
   Responsive Breakpoints (Mobile-First)
   ========================================== */

/* Small phones: < 576px - defaults cover this */

/* Tablets and larger phones: >= 576px */
@media (min-width: 576px) {
  .card-grid.three-col {
    grid-template-columns: repeat(3, 1fr);
  }
}

/* Desktop: >= 768px */
@media (min-width: 768px) {
  .section {
    padding: 5rem 0;
  }

  .menu-toggle {
    display: none;
  }

  .nav-links {
    display: flex !important;
    flex-direction: row !important;
    position: static !important;
    background: none !important;
    padding: 0 !important;
    gap: 2rem !important;
    border: none !important;
  }
}

/* Mobile: < 768px */
@media (max-width: 767px) {
  .menu-toggle {
    display: block;
  }

  .nav-links {
    display: none;
  }

  .nav-links.open {
    display: flex;
  }

  .hero {
    padding: 6rem 0 4rem;
  }

  .hero .btn-group {
    flex-direction: column;
    align-items: center;
  }

  .card-grid.three-col {
    grid-template-columns: 1fr;
  }

  .card,
  .advantage-card {
    padding: 1.75rem 1.5rem;
  }

  .footer-grid {
    grid-template-columns: 1fr;
    gap: 1.5rem;
  }

  .btn-group {
    flex-direction: column;
    align-items: center;
  }
}

/* Large desktop: >= 1024px */
@media (min-width: 1024px) {
  .hero {
    padding: 9rem 0 7rem;
  }
}

/* Print styles */
@media print {
  .nav { position: static; }
  .hero { padding: 2rem 0; background: none; color: var(--text); }
  .cta { background: none; color: var(--text); }
}