/* ===== Navigation Header Styles ===== */
.navigation {
    background: rgba(255, 255, 255, 0.98);
    border-bottom: 1px solid #E0E0E0;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    backdrop-filter: blur(10px);
    box-shadow: var(--shadow-sm);
}

.nav-container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 72px;
}

.nav-brand {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
}

.logo {
    font-size: 28px;
    font-weight: 700;
    color: var(--primary-blue);
    text-decoration: none;
    letter-spacing: -0.5px;
    transition: transform 0.3s ease;
}

.logo:hover {
    transform: scale(1.05);
}

.tagline {
    font-size: 14px;
    color: var(--medium-gray);
    padding-left: var(--space-sm);
    border-left: 1px solid #E0E0E0;
}

.nav-menu {
    display: flex;
    align-items: center;
    gap: var(--space-md);
    position: relative;
    margin-left: auto;
}

.nav-item {
    position: relative;
}

.nav-link {
    color: var(--dark-gray);
    text-decoration: none;
    font-weight: 500;
    padding: var(--space-xs) 12px;
    display: flex;
    align-items: center;
    gap: 6px;
    transition: all 0.2s ease;
    position: relative;
    font-size: 15px;
}

.nav-link:hover {
    color: var(--primary-blue);
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -2px;
    left: 50%;
    width: 0;
    height: 2px;
    background: var(--primary-blue);
    transition: all 0.3s ease;
    transform: translateX(-50%);
}

.nav-link:hover::after {
    width: 80%;
}

.nav-link i {
    width: 16px;
    height: 16px;
}

/* Dropdown Menu */
.has-dropdown > .nav-link::before {
    content: '';
    position: absolute;
    right: 0;
    top: 50%;
    transform: translateY(-50%);
    width: 0;
    height: 0;
    border-left: 4px solid transparent;
    border-right: 4px solid transparent;
    border-top: 4px solid var(--medium-gray);
    transition: all 0.2s ease;
}

.nav-item:hover .has-dropdown > .nav-link::before {
    border-top-color: var(--primary-blue);
    transform: translateY(-50%) rotate(180deg);
}

.dropdown {
    position: absolute;
    top: 100%;
    left: 50%;
    transform: translateX(-50%);
    background: var(--white);
    border-radius: 12px;
    box-shadow: var(--shadow-xl);
    padding: 16px 10px;
    min-width: 300px;
    opacity: 0;
    visibility: hidden;
    transition: all 0.3s ease;
    margin-top: 20px;
    border: 1px solid #E0E0E0;
}

.nav-item:hover .dropdown {
    opacity: 1;
    visibility: visible;
    margin-top: 10px;
}

.dropdown::before {
    content: '';
    position: absolute;
    top: -8px;
    left: 50%;
    transform: translateX(-50%);
    width: 0;
    height: 0;
    border-left: 8px solid transparent;
    border-right: 8px solid transparent;
    border-bottom: 8px solid var(--white);
    z-index: 1;
}

.dropdown-section {
    margin-bottom: var(--space-md);
}

.dropdown-section:last-child {
    margin-bottom: 0;
}

.dropdown-title {
    font-size: 12px;
    font-weight: 600;
    color: var(--medium-gray);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    margin-bottom: var(--space-xs);
    padding-bottom: var(--space-xs);
    border-bottom: 1px solid #F0F0F0;
}

.dropdown-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--space-xs);
}

.dropdown-item {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 10px 6px;
    border-radius: 8px;
    text-decoration: none;
    color: var(--dark-gray);
    transition: all 0.2s ease;
}

.dropdown-item:hover {
    background: var(--light-blue);
    color: var(--primary-blue);
    transform: translateX(4px);
}

.dropdown-item-icon {
    width: 36px;
    height: 36px;
    background: var(--light-gray);
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--primary-blue);
    flex-shrink: 0;
    transition: all 0.2s ease;
}

.dropdown-item:hover .dropdown-item-icon {
    background: var(--primary-blue);
    color: var(--white);
}

.dropdown-item-content h4 {
    font-size: 14px;
    font-weight: 600;
    margin-bottom: 2px;
}

.dropdown-item-content p {
    font-size: 12px;
    color: var(--medium-gray);
    line-height: 1.4;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.dropdown-wide {
    min-width: 600px;
}

.dropdown-columns {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--space-lg);
}

.nav-cta {
    background: var(--primary-blue);
    color: var(--white);
    padding: 12px 24px;
    border-radius: 8px;
    text-decoration: none;
    font-weight: 600;
    transition: all 0.2s ease;
    display: inline-flex;
    align-items: center;
    gap: var(--space-xs);
    box-shadow: 0 2px 8px rgba(46, 91, 186, 0.2);
    margin-left: var(--space-md);
}

.nav-cta:hover {
    background: var(--dark-blue);
    transform: translateY(-2px);
    box-shadow: 0 4px 16px rgba(46, 91, 186, 0.3);
}

.mobile-menu-btn {
    display: none;
    background: none;
    border: none;
    cursor: pointer;
    padding: 8px;
    color: var(--dark-gray);
}

/* ===== Responsive Navigation ===== */
@media (max-width: 768px) {
    .nav-menu {
        display: none;
        position: fixed;
        top: 72px;
        left: 0;
        right: 0;
        bottom: 0;
        background: var(--white);
        flex-direction: column;
        align-items: flex-start;
        padding: var(--space-md);
        gap: var(--space-md);
        overflow-y: auto;
        box-shadow: var(--shadow-lg);
    }
    
    .nav-menu.active {
        display: flex;
    }
    
    .nav-item {
        width: 100%;
    }
    
    .dropdown {
        position: static;
        transform: none;
        opacity: 1;
        visibility: visible;
        margin-top: var(--space-sm);
        box-shadow: none;
        border: 1px solid #E0E0E0;
    }
    
    .dropdown::before {
        display: none;
    }
    
    .mobile-menu-btn {
        display: block;
    }
    
    .nav-cta {
        width: 100%;
        justify-content: center;
        margin-left: 0;
    }
    
    .tagline {
        display: none;
    }
}


/* 语言切换 */
.c-header-language {
    position: relative;
}

.c-header-language__button {
    display: flex;
    align-items: center;
    gap: 6px;
    background: none;
    border: 1px solid var(--border-color);
    padding: 8px 16px;
    border-radius: 20px;
    cursor: pointer;
    color: var(--text-primary);
    font-size: 14px;
    transition: all 0.3s;
    white-space: nowrap;
}

.c-header-language__button:hover {
    border-color: var(--primary-color);
    color: var(--primary-color);
}

.c-header-language__button i {
    color: var(--primary-color);
    width: 16px;
    height: 16px;
}

.c-header-language__dropdown {
    position: absolute;
    top: calc(100% + 10px);
    right: 0;
    background: var(--white);
    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.1);
    border-radius: 4px;
    min-width: 150px;
    opacity: 0;
    visibility: hidden;
    transform: translateY(-10px);
    transition: all 0.3s;
}

.c-header-language:hover .c-header-language__dropdown,
.c-header-language__dropdown.active {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.c-header-language__option {
    display: block;
    padding: 10px 20px;
    color: var(--text-primary);
    text-decoration: none;
    font-size: 14px;
    transition: all 0.3s;
    border-bottom: 1px solid var(--border-color);
}

.c-header-language__option:last-child {
    border-bottom: none;
}

.c-header-language__option:hover,
.c-header-language__option.active {
    background: var(--bg-light);
    color: var(--primary-color);
}