/* Basic Reset & Body Styles */
:root {
    --primary-color: #0056b3;
    --secondary-color: #6c757d;
    --accent-color: #28a745;
    --text-color: #333;
    --light-bg: #f8f9fa;
    --dark-bg: #212529;
    --border-color: #dee2e6;
    --font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-family);
    line-height: 1.6;
    color: var(--text-color);
    background-color: #fff;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

#main-content {
    flex: 1; /* Ensures main content takes available space */
}

a {
    color: var(--primary-color);
    text-decoration: none;
    transition: color 0.3s ease;
}

a:hover {
    color: #003d80;
    text-decoration: underline;
}

ul {
    list-style: none;
}

/* Header Styles */
.main-header {
    background-color: #fff;
    border-bottom: 1px solid var(--border-color);
    padding: 1rem 0;
    box-shadow: 0 2px 4px rgba(0,0,0,0.05);
    position: sticky;
    top: 0;
    z-index: 1000;
}

.header-container {
    max-width: 1200px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0 1.5rem;
}

.logo img {
    height: 40px;
    vertical-align: middle;
}

.main-nav .nav-list {
    display: flex;
    gap: 1.5rem;
}

.nav-item {
    position: relative;
}

.nav-link {
    display: block;
    padding: 0.5rem 0;
    font-weight: 500;
    color: var(--text-color);
    transition: color 0.3s ease;
}

.nav-link:hover {
    color: var(--primary-color);
    text-decoration: none;
}

.dropdown-menu {
    display: none;
    position: absolute;
    background-color: #fff;
    box-shadow: 0 4px 8px rgba(0,0,0,0.1);
    border-radius: 4px;
    min-width: 180px;
    padding: 0.5rem 0;
    z-index: 10;
    top: 100%;
    left: 0;
    opacity: 0;
    visibility: hidden;
    transform: translateY(10px);
    transition: opacity 0.3s ease, transform 0.3s ease, visibility 0.3s;
}

.nav-item:hover .dropdown-menu {
    display: block;
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.dropdown-menu a {
    display: block;
    padding: 0.8rem 1.2rem;
    color: var(--text-color);
    white-space: nowrap;
}

.dropdown-menu a:hover {
    background-color: var(--light-bg);
    text-decoration: none;
}

.header-actions {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.search-box {
    display: flex;
    border: 1px solid var(--border-color);
    border-radius: 20px;
    overflow: hidden;
}

.search-box input {
    border: none;
    padding: 0.5rem 1rem;
    outline: none;
    font-size: 0.9rem;
}

.search-box button {
    background-color: var(--primary-color);
    color: #fff;
    border: none;
    padding: 0.5rem 1rem;
    cursor: pointer;
    transition: background-color 0.3s ease;
}

.search-box button:hover {
    background-color: #003d80;
}

.btn {
    display: inline-block;
    padding: 0.6rem 1.2rem;
    border-radius: 20px;
    text-align: center;
    font-weight: 500;
    transition: background-color 0.3s ease, color 0.3s ease, border-color 0.3s ease;
    cursor: pointer;
    border: 1px solid transparent;
}

.btn-primary {
    background-color: var(--primary-color);
    color: #fff;
}

.btn-primary:hover {
    background-color: #003d80;
    color: #fff;
    text-decoration: none;
}

.btn-secondary {
    background-color: #fff;
    color: var(--primary-color);
    border-color: var(--primary-color);
}

.btn-secondary:hover {
    background-color: var(--light-bg);
    color: #003d80;
    border-color: #003d80;
    text-decoration: none;
}

.mobile-menu-toggle {
    display: none; /* Hidden on desktop */
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.5rem;
    position: relative;
    z-index: 1100;
}

.mobile-menu-toggle span {
    display: block;
    width: 25px;
    height: 3px;
    background-color: var(--text-color);
    margin: 5px 0;
    transition: all 0.3s ease;
}

.mobile-menu-overlay {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.8);
    z-index: 1050;
    justify-content: center;
    align-items: center;
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.3s ease, visibility 0.3s ease;
}

.mobile-menu-overlay.is-active {
    display: flex;
    opacity: 1;
    visibility: visible;
}

.mobile-nav ul {
    text-align: center;
    padding: 2rem;
}

.mobile-nav li {
    margin-bottom: 1.5rem;
}

.mobile-nav a {
    color: #fff;
    font-size: 1.5rem;
    font-weight: 600;
    padding: 0.5rem 1rem;
    transition: color 0.3s ease;
}

.mobile-nav a:hover {
    color: var(--primary-color);
    text-decoration: none;
}


/* Footer Styles */
.main-footer {
    background-color: var(--dark-bg);
    color: #f8f9fa;
    padding: 3rem 0;
    margin-top: 2rem;
}

.footer-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1.5rem;
    display: flex;
    flex-wrap: wrap;
    justify-content: space-between;
    gap: 2rem;
}

.footer-col {
    flex: 1;
    min-width: 200px;
    margin-bottom: 1.5rem;
}

.footer-col h3, .footer-col h4 {
    color: #fff;
    font-size: 1.1rem;
    margin-bottom: 1.2rem;
    position: relative;
}

.footer-col h3::after {
    content: '';
    display: block;
    width: 40px;
    height: 2px;
    background-color: var(--primary-color);
    margin-top: 8px;
}

.footer-col p {
    font-size: 0.9rem;
    line-height: 1.8;
    margin-bottom: 1rem;
}

.footer-col a {
    color: #ccc;
    transition: color 0.3s ease;
}

.footer-col a:hover {
    color: var(--primary-color);
    text-decoration: underline;
}

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

.footer-col ul li {
    margin-bottom: 0.8rem;
}

.footer-logo img {
    height: 32px;
    margin-bottom: 1rem;
}

.social-links {
    margin-top: 1.5rem;
    display: flex;
    gap: 1rem;
}

.social-links a {
    color: #fff;
    font-size: 1.2rem;
    width: 36px;
    height: 36px;
    border-radius: 50%;
    background-color: rgba(255, 255, 255, 0.1);
    display: flex;
    justify-content: center;
    align-items: center;
    transition: background-color 0.3s ease;
}

.social-links a:hover {
    background-color: var(--primary-color);
    text-decoration: none;
}

.newsletter-signup {
    margin-top: 1.5rem;
}

.newsletter-signup form {
    display: flex;
    margin-top: 1rem;
}

.newsletter-signup input[type="email"] {
    border: 1px solid #555;
    background-color: #333;
    padding: 0.7rem 1rem;
    border-radius: 4px 0 0 4px;
    color: #fff;
    outline: none;
    flex-grow: 1;
}

.newsletter-signup input[type="email"]::placeholder {
    color: #aaa;
}

.newsletter-signup button {
    background-color: var(--primary-color);
    color: #fff;
    border: none;
    padding: 0.7rem 1.2rem;
    border-radius: 0 4px 4px 0;
    cursor: pointer;
    transition: background-color 0.3s ease;
}

.newsletter-signup button:hover {
    background-color: #003d80;
}

.footer-bottom {
    border-top: 1px solid #333;
    margin-top: 2rem;
    padding-top: 1.5rem;
    text-align: center;
    font-size: 0.85rem;
    max-width: 1200px;
    margin-left: auto;
    margin-right: auto;
    padding-left: 1.5rem;
    padding-right: 1.5rem;
    display: flex;
    flex-wrap: wrap;
    justify-content: space-between;
    align-items: center;
}

.footer-bottom p {
    margin-bottom: 0.5rem;
    color: #ccc;
}

.footer-nav-bottom a {
    margin: 0 0.8rem;
    color: #ccc;
}

.back-to-top {
    display: inline-flex;
    justify-content: center;
    align-items: center;
    width: 40px;
    height: 40px;
    background-color: var(--primary-color);
    color: #fff;
    border-radius: 50%;
    position: fixed;
    bottom: 20px;
    right: 20px;
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.3s ease, visibility 0.3s ease;
    z-index: 999;
}

.back-to-top.show {
    opacity: 1;
    visibility: visible;
}

/* Iconography (placeholders for a font icon library like Font Awesome) */
.icon-search::before { content: '🔍'; }
.icon-weibo::before { content: '🖝'; } /* Placeholder, ideally use real icon font */
.icon-wechat::before { content: '💬'; } /* Placeholder */
.icon-linkedin::before { content: '🔗'; } /* Placeholder */
.icon-github::before { content: '🐙'; } /* Placeholder */
.icon-location::before { content: '📍'; margin-right: 5px;}
.icon-phone::before { content: '📞'; margin-right: 5px;}
.icon-email::before { content: '📧'; margin-right: 5px;}
.icon-time::before { content: '🕒'; margin-right: 5px;}
.icon-arrow-up::before { content: '⬆️'; }


/* Responsive Design */
@media (max-width: 992px) {
    .main-nav {
        display: none;
    }
    .header-actions .btn {
        display: none; /* Hide login/signup buttons on smaller screens */
    }
    .header-actions .search-box {
        display: none; /* Hide search on smaller screens, can be shown in mobile menu */
    }
    .mobile-menu-toggle {
        display: block;
    }
    .header-container {
        justify-content: space-between;
    }
}

@media (max-width: 768px) {
    .footer-container {
        flex-direction: column;
        align-items: center;
        text-align: center;
    }
    .footer-col {
        min-width: unset;
        width: 100%;
        max-width: 400px; /* Limit width for better readability */
    }
    .footer-col h3::after {
        margin-left: auto;
        margin-right: auto;
    }
    .social-links {
        justify-content: center;
    }
    .newsletter-signup form {
        max-width: 300px;
        margin-left: auto;
        margin-right: auto;
    }
    .footer-bottom {
        flex-direction: column;
        gap: 1rem;
    }
    .footer-nav-bottom {
        display: flex;
        flex-direction: column;
        gap: 0.5rem;
    }
    .footer-nav-bottom a {
        margin: 0;
    }
}
/* 移动端内容区防溢出（系统追加，请勿删除） */
@media (max-width: 768px) {
  .page-content img {
    max-width: 100% !important;
    height: auto !important;
    display: block;
  }
  .page-content {
    overflow-x: hidden;
    max-width: 100%;
  }
  body {
    overflow-x: hidden;
  }
}