/* ===== Reset & Base ===== */
*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
  color: #333;
  background: #fff;
  overflow-x: hidden;
}
a { text-decoration: none; color: inherit; }
ul, li { list-style: none; }
img { max-width: 100%; display: block; }

/* ===== Theme Colors ===== */
:root {
  --primary-color: #78C950;      /* 青草绿 */
  --secondary-color: #E2E2E2;    /* 银河灰 */
  --accent-color: #FFD85A;       /* 柠檬黄 */
  --text-dark: #333333;
  --text-light: #666666;
  --white: #ffffff;
}

/* ===== Header ===== */
.tengzhi-site-header {
  position: sticky; top: 0; left: 0; right: 0; z-index: 100;
  height: 80px;
  display: flex; align-items: center;
  background: var(--white);
  box-shadow: 0 2px 12px rgba(0,0,0,0.08);
}
.tengzhi-header-inner {
  width: 100%; max-width: 1440px; margin: 0 auto;
  padding: 0 60px;
  display: flex; align-items: center; gap: 16px;
}
.tengzhi-logo { display: flex; align-items: center; margin-right: auto; }
.tengzhi-logo img { height: 50px; width: auto; }

/* Nav container */
.tengzhi-nav-menu { display: flex; align-items: center; height: 80px; }
.tengzhi-nav-menu > ul {
  display: flex; list-style: none; margin: 0; padding: 0; height: 100%;
}
.tengzhi-nav-menu > ul > li {
  position: relative; height: 100%;
  display: flex; align-items: center;
  padding: 0 20px;
}
.tengzhi-nav-menu > ul > li > a {
  font-size: 16px; color: var(--text-dark); font-weight: 500;
  transition: color 0.3s; position: relative;
  display: flex; align-items: center; height: 100%;
  white-space: nowrap;
}
/* Underline animation: expands from center */
.tengzhi-nav-menu > ul > li::after {
  content: ''; position: absolute; bottom: 0; left: 50%;
  width: 0; height: 3px; background: var(--primary-color);
  transition: width 0.4s, left 0.4s;
  border-radius: 2px;
}
.tengzhi-nav-menu > ul > li:hover::after,
.tengzhi-nav-menu > ul > li.tengzhi-active::after {
  width: 60px; left: calc(50% - 30px);
}
/* Text color on hover / active */
.tengzhi-nav-menu > ul > li:hover > a,
.tengzhi-nav-menu > ul > li.tengzhi-active > a { color: var(--primary-color); }

/* ===== Dropdown Submenus ===== */
.tengzhi-nav-sub {
  position: absolute; top: 80px; left: 50%;
  transform: translateX(-50%);
  min-width: 200px;
  background: var(--white);
  box-shadow: 0 8px 30px rgba(0,0,0,0.12);
  border-radius: 0 0 8px 8px;
  overflow: hidden;
  max-height: 0; opacity: 0;
  transition: max-height 0.35s ease, opacity 0.25s ease;
  pointer-events: none;
  border-top: 3px solid var(--primary-color);
}
.tengzhi-nav-menu > ul > li:hover > .tengzhi-nav-sub {
  max-height: 500px; opacity: 1;
  pointer-events: auto;
}
.tengzhi-nav-sub a {
  display: block; padding: 12px 24px;
  font-size: 14px; color: var(--text-light);
  transition: background 0.2s, color 0.2s;
  white-space: nowrap;
}
.tengzhi-nav-sub a:hover {
  background: var(--primary-color); color: var(--white);
}
/* Wide dropdown */
.tengzhi-nav-sub.tengzhi-wide {
  min-width: 600px; display: flex; padding: 24px 30px; gap: 32px;
  left: 50%; transform: translateX(-50%);
}
.tengzhi-nav-sub.tengzhi-wide .tengzhi-sub-col { flex: 1; }
.tengzhi-nav-sub.tengzhi-wide .tengzhi-sub-col-title {
  font-size: 14px; font-weight: 700; color: var(--primary-color);
  padding-bottom: 10px; margin-bottom: 8px;
  border-bottom: 2px solid var(--secondary-color);
  letter-spacing: 0.04em;
}
.tengzhi-nav-sub.tengzhi-wide a { padding: 6px 0; font-size: 14px; }
.tengzhi-nav-sub.tengzhi-wide a:hover { background: none; color: var(--primary-color); }

/* Language Switcher */
.tengzhi-lang-switcher {
  position: relative;
  margin-left: 20px;
}
.tengzhi-lang-btn {
  display: flex; align-items: center; gap: 8px;
  padding: 8px 16px;
  background: transparent;
  border: 1px solid var(--secondary-color);
  border-radius: 20px;
  cursor: pointer;
  font-size: 14px;
  color: var(--text-dark);
  transition: all 0.3s;
}
.tengzhi-lang-btn:hover {
  border-color: var(--primary-color);
  color: var(--primary-color);
}
.tengzhi-lang-btn svg {
  width: 16px; height: 16px;
}
.tengzhi-lang-menu {
  position: absolute;
  top: calc(100% + 8px);
  right: 0;
  min-width: 140px;
  background: var(--white);
  border-radius: 8px;
  box-shadow: 0 8px 24px rgba(0,0,0,0.12);
  opacity: 0;
  visibility: hidden;
  transform: translateY(-10px);
  transition: all 0.3s;
  z-index: 1000;
  overflow: hidden;
}
.tengzhi-lang-menu.show {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}
.tengzhi-lang-menu a {
  display: block;
  padding: 10px 16px;
  font-size: 14px;
  color: var(--text-dark);
  transition: all 0.2s;
}
.tengzhi-lang-menu a:hover,
.tengzhi-lang-menu a.active {
  background: var(--primary-color);
  color: var(--white);
}

/* Mobile nav toggle */
.tengzhi-nav-toggle {
  display: none; cursor: pointer; width: 44px; height: 44px;
  position: relative; z-index: 3;
}
.tengzhi-nav-toggle span {
  display: block; width: 24px; height: 2px; background: var(--text-dark);
  position: absolute; left: 10px;
  transition: all 0.4s;
}
.tengzhi-nav-toggle span:nth-child(1) { top: 13px; }
.tengzhi-nav-toggle span:nth-child(2) { top: 21px; }
.tengzhi-nav-toggle span:nth-child(3) { top: 29px; }
.tengzhi-nav-toggle.open span:nth-child(1) { top: 21px; transform: rotate(45deg); }
.tengzhi-nav-toggle.open span:nth-child(2) { opacity: 0; }
.tengzhi-nav-toggle.open span:nth-child(3) { top: 21px; transform: rotate(-45deg); }

/* ===== Footer ===== */
.tengzhi-site-footer {
  position: relative;
  background: linear-gradient(135deg, #1a1a1a 0%, #2d2d2d 100%);
  padding: 80px 120px 40px;
  color: var(--white);
}
.tengzhi-site-footer::before {
  content: '';
  position: absolute; top: 0; left: 0; right: 0; height: 4px;
  background: linear-gradient(90deg, 
    transparent 0%, 
    var(--primary-color) 20%, 
    var(--accent-color) 50%, 
    var(--primary-color) 80%, 
    transparent 100%);
}
.tengzhi-footer-inner {
  max-width: 1450px; margin: 0 auto;
  display: flex; flex-direction: column; gap: 48px;
}
.tengzhi-footer-top {
  display: flex; gap: 60px;
}
.tengzhi-footer-brand { width: 280px; flex-shrink: 0; }
.tengzhi-footer-brand img { height: 48px; width: auto; margin-bottom: 20px; }
.tengzhi-footer-brand p {
  font-size: 14px; color: rgba(255,255,255,0.8);
  line-height: 1.8;
}
.tengzhi-footer-nav-cols {
  flex: 1; display: flex; gap: 40px;
}
.tengzhi-footer-col {
  flex: 1; min-width: 0;
  display: flex; flex-direction: column; gap: 16px;
}
.tengzhi-footer-contact {
  width: 320px; flex-shrink: 0;
  display: flex; flex-direction: column; gap: 16px;
}
.tengzhi-contact-list {
  display: flex; flex-direction: column; gap: 12px;
}
.tengzhi-contact-list li {
  font-size: 14px; line-height: 1.6;
  color: rgba(255,255,255,0.8);
  display: flex; gap: 6px; align-items: baseline;
}
.tengzhi-contact-list li.tengzhi-ct-multi { align-items: flex-start; }
.tengzhi-contact-list .tengzhi-ct-label {
  color: rgba(255,255,255,0.8);
  flex-shrink: 0; font-size: 14px; font-weight: 500;
}
.tengzhi-contact-list a {
  color: inherit;
  transition: color 0.2s;
}
.tengzhi-contact-list a:hover { color: var(--accent-color); }
.tengzhi-footer-col-title {
  position: relative;
  font-size: 18px; font-weight: 700; color: var(--white);
  padding-bottom: 16px;
  letter-spacing: 0.5px;
}
.tengzhi-footer-col-title::after {
  content: '';
  position: absolute; left: 0; bottom: 0;
  width: 32px; height: 3px;
  background: var(--primary-color);
  border-radius: 2px;
}
.tengzhi-footer-col a {
  position: relative;
  font-size: 14px; color: rgba(255,255,255,0.75);
  transition: color 0.25s, transform 0.25s, padding-left 0.25s;
}
.tengzhi-footer-col a::before {
  content: '';
  position: absolute; left: 0; top: 50%;
  width: 0; height: 2px; background: var(--accent-color);
  transform: translateY(-50%);
  transition: width 0.25s;
}
.tengzhi-footer-col a:hover {
  color: var(--white);
  padding-left: 16px;
}
.tengzhi-footer-col a:hover::before { width: 12px; }
.tengzhi-footer-divider {
  width: 100%; height: 1px;
  background: rgba(255,255,255,0.15);
}
.tengzhi-footer-bottom {
  display: flex; align-items: center; justify-content: space-between;
}
.tengzhi-footer-copyright {
  font-size: 13px; color: rgba(255,255,255,0.65);
}
.tengzhi-footer-social {
  display: flex; gap: 20px;
}
.tengzhi-footer-social svg {
  width: 20px; height: 20px; color: rgba(255,255,255,0.6);
  transition: color 0.2s, transform 0.2s; cursor: pointer;
}
.tengzhi-footer-social i:hover svg { 
  color: var(--accent-color);
  transform: scale(1.1);
}

/* ===== Responsive ===== */
@media (max-width: 1200px) {
  .tengzhi-header-inner { padding: 0 30px; }
  .tengzhi-site-footer { padding: 60px 40px 30px; }
  .tengzhi-footer-top { gap: 40px; }
}

@media (max-width: 960px) {
  .tengzhi-footer-top { flex-direction: column; }
  .tengzhi-footer-brand { width: 100%; }
  .tengzhi-footer-contact { width: 100%; }
  .tengzhi-footer-nav-cols { flex-wrap: wrap; gap: 30px; }
}

@media (max-width: 768px) {
  .tengzhi-nav-menu { display: none; }
  .tengzhi-nav-toggle { display: block; }
  .tengzhi-lang-switcher { margin-left: 10px; }
  
  .tengzhi-nav-menu.open {
    display: block;
    position: absolute; top: 80px; left: 0; right: 0;
    background: var(--white); height: auto;
    box-shadow: 0 8px 24px rgba(0,0,0,0.12);
  }
  .tengzhi-nav-menu.open > ul {
    flex-direction: column; height: auto;
  }
  .tengzhi-nav-menu.open > ul > li {
    height: auto; padding: 0;
    border-bottom: 1px solid var(--secondary-color);
    flex-direction: column; align-items: stretch;
  }
  .tengzhi-nav-menu.open > ul > li > a {
    color: var(--text-dark); padding: 14px 24px; height: auto;
  }
  .tengzhi-nav-menu.open > ul > li::after { display: none; }
  .tengzhi-nav-menu.open .tengzhi-nav-sub {
    position: static; transform: none;
    box-shadow: none; border-radius: 0;
    max-height: 0; opacity: 0;
    transition: max-height 0.3s ease, opacity 0.2s ease;
  }
  .tengzhi-nav-menu.open > ul > li.sub-open > .tengzhi-nav-sub {
    max-height: 800px; opacity: 1; pointer-events: auto;
  }
  .tengzhi-nav-menu.open .tengzhi-nav-sub a { padding: 10px 40px; }
  .tengzhi-nav-sub.tengzhi-wide {
    min-width: unset; flex-direction: column; padding: 10px 24px; gap: 8px;
  }
  
  .tengzhi-site-footer { padding: 40px 20px 20px; }
  .tengzhi-footer-nav-cols { gap: 24px; }
  .tengzhi-footer-col { min-width: 120px; }
  .tengzhi-footer-bottom { flex-direction: column; gap: 16px; text-align: center; }
}