* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}
:root {
    --primary-color: #0e6ac7;
    --secondary-color: #3449db;
    --light-color: #f5f5f5;
    --dark-color: #2d4a8a;
    --text-color: #333333;
    --white: #ffffff;
    --gray: #7f8c8d;
    --green-btn: #2ecc71;
    --transition: all 0.3s ease;
}
body {
    line-height: 1.6;
    color: var(--text-color);
    background-color: var(--light-color);
    transition: var(--transition);
}
.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 15px;
}
a {
    text-decoration: none;
    color: inherit;
}
ul {
    list-style: none;
}
[lang="en"] { display: none !important; }
body.lang-en [lang="en"] { display: block !important; }
body.lang-en [lang="zh"] { display: none !important; }

.header {
    position: sticky;
    top: 0;
    z-index: 1000;
    background-color: #ffffff;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    transition: var(--transition);
}
.header.scrolled {
    background-color:  #ffffff;
}
.header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 12px 15px;
    min-height: 70px;
    position: relative;
    
}
.header-right {
    display: flex;
    align-items: center;
    gap: 0;
     margin-left: auto;
}
.menu-toggle-wrapper {
    position: relative;
    width: 30px;
    height: 24px;
    order: 99;
    margin-left: -10px;
    margin-right: 0px;
      display: none;
}
.logo img {
    height: 55px;
    width: auto;
    object-fit: contain;
    margin-left: 40px;
}

.main-nav {
  position: absolute;
  left: 50%;
  transform: translateX(-50%);
}


.main-nav ul {
    display: flex;
  
    align-items: center;
    list-style: none;
    
    gap: 30px;
}
.main-nav a {
   
    font-weight: 500;   
    transition: var(--transition);
    color: #333;   
    font-size: 18px;
    white-space: nowrap;
    padding: 8px 0;
    position: relative;
    transition: all 0.3s ease;
    text-decoration: none;
    font-weight: 500;
    letter-spacing: 0.5px; 
}
.main-nav a:hover,
.main-nav a.active {
    color: #003366;
    font-weight: 700;
    text-decoration: underline;
    text-underline-offset: 6px;
    transform: translateY(-3px);
    transition: all 0.25s cubic-bezier(0.25, 0.8, 0.25, 1);
  

}
.nav-item {
    position: relative;

}
.dropdown-menu {
    position: absolute;
    top: 100%;
    left: 0;
    width: 220px;
    background: var(--white);
    box-shadow: 0 5px 15px rgba(0,0,0,0.1);
    border-radius: 6px;
    opacity: 0;
    visibility: hidden;
    transform: translateY(10px);
    transition: var(--transition);
    z-index: 999;
    padding: 10px 0;
    display: block;    
    flex-wrap: wrap;
}
.dropdown-menu li {
    width: 100%;
    height: auto;
    line-height: 1;
     margin: 0; 
}
.dropdown-menu a {
    
    display: block;
    font-size: 16px;
    font-weight: 400;
    white-space: nowrap;
    padding: 5px 15px; /* 优化点击区域 */
    color: #333;  
    transition: var(--transition);
    border-radius: 4px;
    




}
.dropdown-menu a:hover {
   color: #003366;
    background: var(--light-color);
    padding-left: 28px;
    font-weight: 600;
    text-decoration: underline;
    text-underline-offset: 4px;
}
.nav-item:hover .dropdown-menu {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}
.hamburger {
    position: absolute;
    width: 100%;
    height: 100%;
    cursor: pointer;
    background: transparent;
    border: none;
    display: none;
    flex-direction: column;
    justify-content: space-between;
    padding: 0;
    transition: opacity 0.3s;
}
.hamburger span {
    display: block;
    width: 100%;
    height: 3px;
    background-color: #100363;
    border-radius: 3px;
}
.close-menu {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    font-size: 28px;
    color:#100363;
    cursor: pointer;
    background: transparent;
    border: none;
    display: none;
    line-height: 1;
    z-index: 10;
}
.mobile-menu {
    width: 100%;
    background-color: var(--white);
    z-index: 999;
    transition: var(--transition);
    padding: 0 20px;
    overflow: hidden;
    max-height: 0;
    opacity: 0;
    box-shadow: 0 2px 10px rgba(196, 60, 60, 0.151);
}
.mobile-menu.active {
    max-height: 1000px;
    opacity: 1;
    padding: 20px;
}
.mobile-menu ul {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    align-items: flex-start;
    width: 100%;
}
.mobile-menu > ul > li {
    width: 100%;
}
.mobile-menu a {
    color: var(--primary-color);
    font-size: 1.1rem;
    font-weight: 500;
    display: block;
    width: 100%;
    padding: 12px 0;
    border-bottom: 1px solid #eee;
}
.mobile-menu a:hover,
.mobile-menu a.active {
    color: var(--secondary-color);
}
.mobile-sub-tabs {
    height: 0;
    overflow: hidden;
    transition: var(--transition);
    width: 100%;
    padding-left: 15px;
}
.mobile-sub-tabs.active {
    height: auto;
    padding: 8px 0 8px 15px;
}
.mobile-sub-tabs li {
    width: 100%;
}
.mobile-sub-tabs a {
    font-size: 1rem;
    color: var(--gray);
    padding: 10px 0;
    border: none;
    width: 100%;
}
.mobile-sub-tabs a:hover {
    color: var(--primary-color);
    padding-left: 8px;
    background: #f9f9f9;
}
.lang {
    display: flex;
    gap: 8px;
    margin: 10px 15px;
}
.lang button {
    background: transparent;
    border: 1px solid #fa5d14;
    color:  #100363;
    padding: 4px 8px;
    border-radius: 4px;
    cursor: pointer;
    display: none;
    align-items: center;
    gap: 4px;
}
.lang button.active {
    background: transparent;
    color:  #100363;
}
.lang img {
    height: 16px;
    width: 16px;
    object-fit: cover;
}
body:not(.lang-en) .lang button[data-lang="en"] { display: flex; }
body.lang-en .lang button[data-lang="en"] { display: none; }
body.lang-en .lang button[data-lang="zh"] { display: flex; }

@media (max-width: 992px) {
    .main-nav {
        display: none !important;
    }
    .menu-toggle-wrapper
     {     display: block !important;   }
    .hamburger {
        display: flex !important;
    }
    .header.active .hamburger {
        opacity: 0;
        pointer-events: none;
    }
    .header.active .close-menu {
        display: block;
    }
}