/* 全局重置与基础样式 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: "Microsoft YaHei", Arial, sans-serif;
}

a {
    text-decoration: none;
    color: #333;
}

ul, ol {
    list-style: none;
}

.container {
    width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* 响应式适配：小屏幕（平板/手机） */
@media (max-width: 1200px) {
    .container {
        width: 90%;
    }
}

/* 头部导航样式 */
.header {
    border-bottom: 1px solid #eee;
    background-color: #fff;
    position: sticky;
    top: 0;
    z-index: 999;
    box-shadow: 0 2px 5px rgba(0,0,0,0.05);
}

.nav-wrapper {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 80px;
}

.logo a {
    font-size: 24px;
    font-weight: bold;
    color: #0056b3; /* 外贸企业常用深蓝主色调 */
}

/* PC端导航 */
.nav-pc {
    display: flex;
}

.nav-pc li {
    margin-left: 40px;
}

.nav-pc li a {
    font-size: 16px;
    padding: 5px 0;
    border-bottom: 2px solid transparent;
    transition: all 0.3s ease;
}

.nav-pc li a:hover,
.nav-pc li a.active {
    color: #0056b3;
    border-bottom: 2px solid #0056b3;
}

/* 移动端导航开关（默认隐藏） */
.nav-mobile-toggle {
    display: none;
    font-size: 24px;
    cursor: pointer;
    color: #333;
}

/* 移动端导航（默认隐藏） */
.nav-mobile {
    display: none;
    background-color: #fff;
    border-bottom: 1px solid #eee;
    padding: 10px 0;
}

.nav-mobile li {
    padding: 15px 20px;
    border-bottom: 1px solid #f5f5f5;
}

.nav-mobile li a {
    font-size: 16px;
    display: block;
    transition: all 0.3s ease;
}

.nav-mobile li a:hover,
.nav-mobile li a.active {
    color: #0056b3;
}

/* 响应式：移动端显示开关，隐藏PC端导航 */
@media (max-width: 768px) {
    .nav-pc {
        display: none;
    }

    .nav-mobile-toggle {
        display: block;
    }

    .nav-mobile.show {
        display: block;
    }
}

/* 页脚样式 */
.footer {
    background-color: #333;
    color: #fff;
    padding: 60px 0 30px;
    margin-top: 80px;
}

.footer-wrapper {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 40px;
    margin-bottom: 40px;
}

.footer-item h3 {
    font-size: 18px;
    margin-bottom: 20px;
    padding-bottom: 10px;
    border-bottom: 2px solid #0056b3;
}

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

.footer-item ul li a {
    color: #ccc;
    transition: all 0.3s ease;
}

.footer-item ul li a:hover {
    color: #fff;
    margin-left: 5px;
}

.footer-contact p {
    color: #ccc;
    margin-bottom: 10px;
    line-height: 1.8;
}

/* 版权信息 */
.copyright {
    text-align: center;
    padding-top: 30px;
    border-top: 1px solid #444;
    color: #ccc;
    font-size: 14px;
}

/* 响应式：页脚网格适配 */
@media (max-width: 992px) {
    .footer-wrapper {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 576px) {
    .footer-wrapper {
        grid-template-columns: 1fr;
    }
}

/* 通用按钮样式 */
.btn {
    display: inline-block;
    padding: 12px 30px;
    background-color: #0056b3;
    color: #fff !important;
    border-radius: 4px;
    font-size: 16px;
    border: none;
    cursor: pointer;
    transition: all 0.3s ease;
}

.btn:hover {
    background-color: #004085;
    transform: translateY(-2px);
}

/* 通用标题样式 */
.section-title {
    text-align: center;
    margin-bottom: 60px;
    position: relative;
}

.section-title h2 {
    font-size: 32px;
    color: #333;
    margin-bottom: 15px;
}

.section-title p {
    color: #666;
    font-size: 16px;
    width: 60%;
    margin: 0 auto;
}

.section-title::after {
    content: "";
    display: block;
    width: 80px;
    height: 3px;
    background-color: #0056b3;
    position: absolute;
    top: 40px;
    left: 50%;
    transform: translateX(-50%);
}

@media (max-width: 768px) {
    .section-title p {
        width: 90%;
    }

    .section-title h2 {
        font-size: 26px;
    }
}