/* ===== 全局重置 ===== */
*,::before,::after{margin:0;padding:0;box-sizing:border-box}

/* ===== 基础元素 ===== */
html{scroll-behavior:smooth}
body{
  font-family:'Segoe UI',system-ui,-apple-system,BlinkMacSystemFont,Roboto,sans-serif;
  background:#f8fafc;
  color:#2d3e50;
  -webkit-font-smoothing:antialiased
}
a{text-decoration:none;color:inherit}

/* ===== 头部导航 ===== */
#header{
  background:#fff;
  box-shadow:0 4px 20px rgba(0,20,30,.05);
  padding:12px 0;
  position:sticky;
  top:0;
  z-index:997;
  border-bottom:1px solid rgba(0,40,80,.05)
}

/* ===== 布局容器 ===== */
.container{
  width:100%;
  max-width:1200px;
  margin:0 auto;
  padding:0 20px
}
.container::after{content:"";display:table;clear:both}
.float-left{float:left}
.float-right{float:right}

/* ===== Logo ===== */
.logo h1{font-size:1.6rem;font-weight:600;letter-spacing:-.3px}
.logo h1 a{color:#0b2e4a;transition:color .2s}
.logo h1 a:hover{color:#3b7cbf}

/* ===== 导航菜单 ===== */
.nav-menu{float:right}
.nav-menu ul{list-style:none;display:flex;gap:1.8rem}
.nav-menu ul li{position:relative}
.nav-menu ul li a,.nav-menu ul li .dropbtn{
  font-weight:500;
  color:#2a4b6e;
  padding:6px 0;
  border-bottom:2px solid transparent;
  transition:.2s;
  display:inline-block;
  vertical-align:middle;
  line-height:1.4
}
.nav-menu ul li .dropbtn{
  font-family:inherit;
  font-size:1rem;
  background:transparent;
  border:none;
  cursor:pointer
}
.nav-menu ul li.active>a,
.nav-menu ul li a:hover,
.nav-menu ul li .dropbtn:hover{
  border-bottom-color:#3b7cbf;
  color:#0b2e4a
}

/* ===== 下拉菜单 ===== */
.dropdown{position:relative;display:inline-block}
.dropdown-content{
  display:none;
  position:absolute;
  top:38px;
  left:0;
  background:#fff;
  min-width:280px;
  box-shadow:0 12px 28px rgba(0,20,40,.12);
  border-radius:10px;
  padding:10px 0;
  z-index:999
}
.dropdown-content a{display:block;padding:8px 20px;color:#1e3a5f;font-size:.95rem}
.dropdown-content a:hover{background:#eef4fa}
.dropdown:hover .dropdown-content{display:block}

/* ===== 主体通用 ===== */
.team{padding:60px 0}
.section-title{text-align:center;margin-bottom:48px}
.section-title h2{font-size:2rem;font-weight:600;color:#132e48;letter-spacing:-.02em;margin-bottom:20px}
.section-title p{font-size:1.15rem;color:#2f577b;max-width:800px;margin:.5rem auto}
.section-title p:last-of-type{
  background:#eaf0f8;
  padding:14px 24px;
  border-radius:40px;
  font-size:.95rem;
  color:#1f4870;
  border:1px solid #cbddee;
  display:inline-block
}

/* ===== 页脚 ===== */
#footer{
  background:#eef4fa;
  padding:30px 0;
  margin-top:40px;
  border-top:1px solid #d0e0f0;
  text-align:center;
  color:#1e4468
}
#footer .copyright a{font-weight:500;border-bottom:1px dashed #7b9ec0}

/* ===== 回到顶部 ===== */
.back-to-top{
  position:fixed;
  bottom:30px;
  right:30px;
  background:#2b5d8c;
  color:#fff;
  width:48px;
  height:48px;
  border-radius:30px;
  display:flex;
  align-items:center;
  justify-content:center;
  font-size:28px;
  box-shadow:0 8px 18px rgba(0,60,120,.25);
  transition:.2s;
  z-index:998
}
.back-to-top:hover{background:#184472;transform:scale(1.06)}

/* ===== 响应式 ===== */
@media(max-width:991px){
  .nav-menu ul{gap:1rem}
  .logo h1{font-size:1.3rem}
}