/* psnav6.css 经典红黑上下线终版 - 完全匹配用户原始HTML结构 */
* { margin: 0; padding: 0; box-sizing: border-box; }

body {
    font-family: "Microsoft YaHei", "PingFang SC", "Helvetica Neue", Arial, sans-serif;
    font-size: 14px; line-height: 1.8; color: #505050;
    background-color: #ffffff;
    -webkit-font-smoothing: antialiased;
    -webkit-tap-highlight-color: transparent;
    min-width: 320px;
}
img { max-width: 100%; height: auto; border: none; }
a { color: #606060; text-decoration: none; transition: color 0.2s ease; }

/* ========== 导航栏 ========== */
.navbar {
    width: 100%; list-style: none; margin: 0;
    height: 180px;
    display: flex; align-items: flex-end; justify-content: flex-start;
    background: linear-gradient(to bottom, #ffffff 0%, #a2d8f6 100%);
    border-bottom: 1px solid #7cc3ea;
}
.navbar .logo { list-style: none; padding-bottom: 10px; margin-right: auto; }
.navbar .logo a { display: block; height: 80px; line-height: 80px; }
.navbar .logo img { max-height: 80px; vertical-align: middle; }
.navbar .nbtns, .navbar .nbtn { display: inline-block; list-style: none; margin: 0; }

/* 按钮基础：所有按钮预设透明上下边框防跳动 */
.navbar .nbtns a, .navbar .nbtn a {
    display: block;
    height: 80px; line-height: 74px; /* 80 - 上下各3px边框 */
    padding: 0 20px;
    color: #333; font-size: 16px; font-weight: 500;
    background: transparent; border-radius: 0;
    transition: all 0.2s ease;
    border-top: 3px solid transparent;
    border-bottom: 3px solid transparent;
    white-space: nowrap;
}

/* Hover：所有按钮（含未选中的）hover时文字变红 + 只有底部红线 */
.navbar .nbtns a:hover, .navbar .nbtn a:hover {
    color: #e60000;
    border-bottom-color: #e60000;
    background: transparent;
}

/* ======== 【核心修复】选中/当前页：.nbtns 本身就是选中标记 ======== */
/* 你的原HTML规则：<li class="nbtns"> 表示当前页，普通按钮是 <li class="nbtn">
   所以选中态直接匹配 .navbar .nbtns > a，不需要任何额外的active类 */
.navbar .nbtns > a {
    color: #c80000;
    border-top-color: #c80000;
    border-bottom-color: #c80000;
}
/* 同时兼容你后续可能给<a>加active/current类的写法，不冲突 */
.navbar .nbtn > a.active,
.navbar .nbtn > a.current {
    color: #c80000;
    border-top-color: #c80000;
    border-bottom-color: #c80000;
}

/* 选中项hover时保持双划线，不要被上面的hover规则覆盖掉顶线 */
.navbar .nbtns > a:hover,
.navbar .nbtn > a.active:hover,
.navbar .nbtn > a.current:hover {
    color: #c80000;
    border-top-color: #c80000;
    border-bottom-color: #c80000;
}

/* ========== 主内容区 ========== */
main { max-width: 960px; margin: 40px auto; padding: 0 20px; }

/* ========== 页脚 ========== */
.site-footer {
    width: 100%; padding: 30px 20px; margin-top: 60px;
    background-color: #f5f5f5; border-top: 1px solid #e0e0e0; text-align: center;
}
.copyright { font-size: 13px; color: #888; margin-bottom: 8px; }
.beian { font-size: 12px; color: #999; line-height: 1.8; }
.beian a { color: #999; margin: 0 6px; }
.beian a:hover { color: #c80000; }
.beian img { width: 15px; vertical-align: middle; margin: 0 2px; }

/* 工具类 */
.text-red { color: #c80000 !important; }
.text-green { color: #078758 !important; }
.text-center { text-align: center; }
.mt-20 { margin-top: 20px; }
.mb-20 { margin-bottom: 20px; }

/* ========== 响应式 ========== */
@media (min-width: 1000px) {
    .navbar {
        padding: 0 calc((100% - 960px)/2);
        /* 关键：border-box下calc内边距已包含在width:100%中，内容严格=960px不溢出 */
        box-sizing: border-box;
    }
    .site-footer { padding: 30px calc((100% - 960px)/2); box-sizing: border-box; }
}

@media (max-width: 999px) and (min-width: 769px) {
    .navbar { height: 120px; padding: 0 30px; box-sizing: border-box; }
    .navbar .logo a { height: 60px; line-height: 60px; }
    .navbar .logo img { max-height: 60px; }
    .navbar .nbtns a, .navbar .nbtn a {
        height: 50px; line-height: 46px; padding: 0 14px; font-size: 15px;
        border-top-width: 2px; border-bottom-width: 2px;
    }
    main { margin: 30px auto; }
}

@media (max-width: 768px) {
    .navbar {
        height: auto; min-height: 120px;
        /* 修复：改回水平主轴，允许换行 */
        flex-direction: row; flex-wrap: wrap; 
        align-items: center; justify-content: center;
        padding: 16px 16px 0 16px; box-sizing: border-box;
    }
    /* 修复：logo单独占满一行居中 */
    .navbar .logo { margin-right: 0; margin-bottom: 8px; width: 100%; text-align: center; }
    .navbar .logo a { height: 50px; line-height: 50px; }
    .navbar .logo img { max-height: 50px; }
    .navbar .nbtns, .navbar .nbtn { flex: 0 0 auto; }
    .navbar .nbtns a, .navbar .nbtn a {
        height: 44px; line-height: 40px; padding: 0 14px; font-size: 15px;
        border-top-width: 2px; border-bottom-width: 2px;
    }
    main { margin: 24px auto; padding: 0 16px; }
}

@media (max-width: 480px) {
    .navbar { padding: 12px 10px 0 10px; min-height: 110px; }
    .navbar .logo a { height: 44px; line-height: 44px; }
    .navbar .logo img { max-height: 44px; }
    .navbar .nbtns a, .navbar .nbtn a {
        height: 40px; line-height: 36px; padding: 0 10px; font-size: 14px;
    }
    .site-footer { padding: 24px 12px; }
}

@media print {
    .navbar, .site-footer { display: none; }
    body { background: #fff; }
}