/* 基础样式和全局组件 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

body {
    line-height: 1.6;
    color: #333;
    background-color: #f9f9f9;
}

.container {
    width: 90%;
    max-width: 1200px;
    margin: 0 auto;
}

/* 导航栏活动链接样式 */
nav ul li a.active {
    color: #4dabf7;
}

nav ul li a.active:after {
    content: '';
    position: absolute;
    width: 100%;
    height: 2px;
    background-color: #4dabf7;
    bottom: 0;
    left: 0;
}

/* Header & Navigation */
header {
    background-color: #ffffff;
    padding: 15px 0;
    position: fixed;
    width: 100%;
    top: 0;
    z-index: 1000;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

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

.logo {
    color: #0a2c5e;
    font-size: 28px;
    font-weight: 700;
    text-decoration: none;
    display: flex;
    align-items: center;
    z-index: 1001;
    position: relative;
}

.logo-img {
    height: 50px;
    width: auto;
    display: block;
}

.logo span {
    color: #4dabf7;
}

.logo i {
    margin-right: 10px;
    font-size: 32px;
}

nav {
    z-index: 1001;
    position: relative;
}

nav ul {
    display: flex;
    list-style: none;
}

nav ul li {
    margin-left: 30px;
}

nav ul li a {
    color: #0a2c5e;
    text-decoration: none;
    font-weight: 600;
    font-size: 17px;
    transition: color 0.3s;
    position: relative;
    padding-bottom: 8px;
    display: inline-block;
    pointer-events: auto;
}

nav ul li a:hover {
    color: #4dabf7;
}

/* Dropdown Arrow */
.dropdown-arrow {
    font-size: 12px;
    margin-left: 6px;
    transition: transform 0.3s ease;
}

.dropdown-trigger:hover .dropdown-arrow {
    transform: rotate(180deg);
}

/* Mega Dropdown */
.dropdown-trigger {
    position: static;
}

.mega-dropdown {
    position: absolute;
    top: 100%;
    margin-top: -1px;
    left: 0;
    width: 100%;
    transform: translateY(8px);
    background: #ffffff;
    border-top: 2px solid #4dabf7;
    border-radius: 0 0 12px 12px;
    box-shadow: 0 20px 50px rgba(10, 44, 94, 0.18), 0 0 0 1px rgba(10, 44, 94, 0.06);
    padding: 24px 24px 28px;
    opacity: 0;
    visibility: hidden;
    transition: all 0.35s cubic-bezier(0.4, 0, 0.2, 1);
    z-index: 9999;
    pointer-events: none;
}

.dropdown-trigger:hover .mega-dropdown {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
    pointer-events: auto;
}

.dropdown-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    grid-template-rows: repeat(2, auto);
    gap: 12px;
}

.dropdown-item {
    display: flex;
    flex-direction: row;
    align-items: center;
    text-align: left;
    padding: 12px 16px;
    border-radius: 10px;
    text-decoration: none;
    color: #0a2c5e;
    transition: all 0.25s ease;
    cursor: pointer;
    gap: 12px;
}

.dropdown-item:hover {
    background: rgba(77, 171, 247, 0.1);
    transform: translateY(-2px);
}

.dropdown-item:hover .dropdown-icon {
    transform: scale(1.06);
    box-shadow: 0 4px 14px rgba(77, 171, 247, 0.3);
}

.dropdown-icon {
    width: 48px;
    height: 48px;
    min-width: 48px;
    border-radius: 50%;
    background: #f0f7ff;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    overflow: hidden;
    border: 1px solid rgba(77, 171, 247, 0.15);
}

.dropdown-icon img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.dropdown-item span {
    font-size: 14px;
    font-weight: 600;
    line-height: 1.4;
    color: #333;
    transition: color 0.25s ease;
}

.dropdown-item:hover span {
    color: #0a2c5e;
}

/* Hero Section */
.hero {
    color: white;
    padding: 180px 0 100px;
    text-align: center;
}

.hero h1 {
    font-size: 42px;
    margin-bottom: 25px;
    line-height: 1.2;
    max-width: 900px;
    margin-left: auto;
    margin-right: auto;
}

.hero-subtitle {
    font-size: 20px;
    max-width: 800px;
    margin: 0 auto 40px;
    opacity: 0.9;
}

.btn {
    display: inline-block;
    background: #4dabf7;
    color: white;
    padding: 16px 40px;
    border-radius: 8px;
    text-decoration: none;
    font-weight: 600;
    font-size: 16px;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    border: none;
    cursor: pointer;
    box-shadow: 0 4px 12px rgba(77, 171, 247, 0.25);
    letter-spacing: 0.5px;
}

.btn:hover {
    background: #339af0;
    transform: translateY(-3px);
    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.2);
}

.btn-outline {
    background-color: transparent;
    border: 2px solid #4dabf7;
    color: #4dabf7;
}

.btn-outline:hover {
    background-color: #4dabf7;
    color: white;
}

/* 浅色背景类 - 用于交替背景 */
.bg-light {
    background-color: #f0f8ff !important;
}

/* Section Title */
.section-title {
    text-align: center;
    margin-bottom: 50px;
}

.section-title h2 {
    color: #0a2c5e;
    font-size: 36px;
    margin-bottom: 15px;
    position: relative;
    display: inline-block;
}

.section-title h2:after {
    content: '';
    position: absolute;
    width: 70px;
    height: 4px;
    background-color: #4dabf7;
    bottom: -10px;
    left: 50%;
    transform: translateX(-50%);
}

.section-title p {
    color: #666;
    font-size: 18px;
    max-width: 800px;
    margin: 0 auto;
}

/* Contact Section */
.contact {
    padding: 100px 0;
    background-color: white;
    color: #0a2c5e;
}

.contact-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 50px;
}

.contact-info h3, .contact-form h3 {
    font-size: 28px;
    margin-bottom: 25px;
    color: #0a2c5e;
}

.contact-info p {
    margin-bottom: 20px;
    opacity: 0.9;
    color: #555;
}

.contact-info .contact-logo {
    max-width: 150px;
    height: auto;
    margin-bottom: 30px;
    display: block;
}

.contact-details {
    margin-top: 30px;
}

.contact-detail {
    display: flex;
    align-items: center;
    margin-bottom: 20px;
}

.contact-detail i {
    font-size: 20px;
    color: #4dabf7;
    margin-right: 15px;
    width: 30px;
}

.form-group {
    margin-bottom: 25px;
}

.form-group label {
    display: block;
    margin-bottom: 8px;
    font-weight: 600;
}

.form-group input, .form-group textarea {
    width: 100%;
    padding: 14px 16px;
    border-radius: 8px;
    border: 1px solid #d1d5db;
    background-color: #ffffff;
    color: #333;
    font-size: 15px;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.05);
}

.form-group input:focus, .form-group textarea:focus {
    border-color: #4dabf7;
    outline: none;
    box-shadow: 0 0 0 3px rgba(77, 171, 247, 0.15);
}

.form-group input::placeholder, .form-group textarea::placeholder {
    color: #999;
}

.form-group textarea {
    height: 140px;
    resize: vertical;
    line-height: 1.5;
}

/* Footer */
footer {
    background-color: #071b3d;
    color: white;
    padding: 50px 0 20px;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 40px;
    margin-bottom: 40px;
}

.footer-column h3 {
    font-size: 22px;
    margin-bottom: 25px;
    color: #4dabf7;
}

.footer-column ul {
    list-style: none;
}

.footer-column ul li {
    margin-bottom: 12px;
}

.footer-column ul li a {
    color: #ddd;
    text-decoration: none;
    transition: color 0.3s;
}

.footer-column ul li a:hover {
    color: #4dabf7;
}

.copyright {
    text-align: center;
    padding-top: 30px;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    color: #aaa;
    font-size: 15px;
}

/* Responsive Styles */
@media (max-width: 992px) {
    .hero {
        padding: 160px 0 80px;
    }
    
    .hero h1 {
        font-size: 36px;
    }
    
    nav ul li {
        margin-left: 20px;
    }

    .mega-dropdown {
        min-width: 560px;
        padding: 20px 16px;
    }

    .dropdown-icon {
        width: 44px;
        height: 44px;
        font-size: 19px;
        border-radius: 10px;
    }

    .dropdown-item {
        padding: 14px 10px 12px;
    }

    .dropdown-item span {
        font-size: 12px;
    }
}

@media (max-width: 768px) {
    .nav-container {
        flex-direction: column;
    }
    
    .logo {
        margin-bottom: 20px;
    }
    
    nav ul li {
        margin: 0 10px;
    }
    
    .hero {
        padding: 180px 0 80px;
    }
    
    .hero h1 {
        font-size: 30px;
    }
    
    .section-title h2 {
        font-size: 30px;
    }

    .mega-dropdown {
        min-width: 90vw;
        left: 50%;
        transform: translateX(-50%) translateY(8px);
        padding: 16px 12px;
        border-radius: 8px;
    }

    .dropdown-trigger:hover .mega-dropdown {
        transform: translateX(-50%) translateY(0);
    }

    .dropdown-grid {
        grid-template-columns: repeat(3, 1fr);
        gap: 8px;
    }

    .dropdown-icon {
        width: 38px;
        height: 38px;
        font-size: 17px;
        border-radius: 8px;
    }

    .dropdown-item {
        padding: 12px 8px 10px;
        border-radius: 8px;
    }

    .dropdown-item span {
        font-size: 11px;
    }
}

@media (max-width: 576px) {
    .hero h1 {
        font-size: 26px;
    }
    
    nav ul {
        flex-wrap: wrap;
        justify-content: center;
    }
    
    nav ul li {
        margin: 5px 10px;
    }
}