/* M6P_NAV_CSS v1 — 全站导航样式单一来源 (/partials/site-nav.css) */
/* 含：顶栏、logo、下拉、EN 按钮、移动端汉堡抽屉 */

header {
    position: fixed; top: 0; left: 0; width: 100%;
    z-index: 100;
    padding: 14px 48px;
    display: flex; justify-content: space-between; align-items: center;
    background: rgba(255,255,255,0.92);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid rgba(0,180,120,0.15);
}
.logo { display: flex; align-items: center; gap: 8px; }
.logo img { height: 32px; width: auto; display: block; }

/* ===== 桌面端 ===== */
@media (min-width: 769px) {
    .nav-main { display: flex; align-items: center; gap: 2px; }
    .nav-item { position: relative; }
    .nav-item > a {
        color: #3d6b5a; text-decoration: none; margin-left: 12px; font-size: 0.9em;
        font-weight: 500; padding: 6px 10px; border-radius: 6px; display: block;
        transition: color .3s, background .3s;
    }
    .nav-item > a:hover, .nav-item > a.active { color: #0d7a5e; }
    .nav-item > a:hover { background: rgba(0,180,120,0.06); }
    .nav-item > a .caret { font-size: 0.7em; margin-left: 3px; color: #7a9a8a; }
    .nav-item .dropdown {
        position: absolute; top: 100%; left: 12px; min-width: 190px; background: #fff;
        border: 1px solid #e0ede8; border-radius: 10px;
        box-shadow: 0 8px 28px rgba(20,80,60,0.12); padding: 8px;
        opacity: 0; visibility: hidden; transform: translateY(-6px);
        transition: opacity .22s, transform .22s, visibility .22s; z-index: 200;
    }
    .nav-item .dropdown a {
        display: block; padding: 10px 16px; color: #3d6b5a; text-decoration: none;
        font-size: 0.88em; border-radius: 6px;
        transition: background .2s, color .2s, padding-left .2s;
    }
    .nav-item .dropdown a:hover { background: #e6f5ef; color: #0d7a5e; padding-left: 18px; }
    .nav-item .dropdown a.active { color: #0d7a5e; font-weight: 600; }
    .nav-item:hover .dropdown { opacity: 1; visibility: visible; transform: translateY(0); }
    .nav-toggle { display: none; }
    .nav-scrim { display: none; }
}

/* ===== EN 按钮 ===== */
.nav-item.lang-item { margin-left: 12px; display: flex; align-items: center; }
.nav-item.lang-item > a {
    margin-left: 0; color: #3d6b5a; font-size: .9em; font-weight: 500;
    padding: 6px 10px; border: 1px solid rgba(61,107,90,.45); border-radius: 6px;
    text-decoration: none; line-height: 1; white-space: nowrap;
    transition: color .2s, border-color .2s, background .2s;
}
.nav-item.lang-item > a:hover { color: #0d7a5e; border-color: #0d7a5e; background: rgba(0,180,120,.06); }

/* ===== 汉堡按钮 ===== */
.nav-toggle {
    display: none; position: relative; z-index: 101;
    width: 40px; height: 40px; border: 1px solid rgba(13,122,94,.28);
    background: rgba(13,122,94,.08);
    cursor: pointer; padding: 6px; border-radius: 8px;
    box-shadow: 0 1px 6px rgba(13,122,94,.10);
    flex: 0 0 auto;
}
.nav-toggle:hover { background: rgba(13,122,94,.16); }
.nav-toggle span {
    display: block; width: 100%; height: 2.5px; border-radius: 2px;
    background: #0d7a5e; margin: 4px 0; transition: transform .3s, opacity .3s;
    flex: 0 0 2.5px; min-height: 2.5px;
}
body.nav-open .nav-toggle span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
body.nav-open .nav-toggle span:nth-child(2) { opacity: 0; }
body.nav-open .nav-toggle span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ===== 移动端抽屉 ===== */
@media (max-width: 768px) {
    html, body { overflow-x: hidden; }
    header {
        flex-wrap: nowrap; justify-content: space-between;
        padding: 10px 16px; gap: 8px;
        width: 100vw; max-width: 100vw; left: 0; right: 0;
    }
    .nav-toggle { display: flex; flex-direction: column; justify-content: center; flex: 0 0 40px; }
    .nav-main {
        position: fixed; top: 0; right: 0; z-index: 100;
        width: 80%; max-width: 320px; height: 100vh;
        background: #ffffff; flex-direction: column;
        align-items: stretch; justify-content: flex-start;
        padding: 74px 20px 30px; margin: 0; gap: 0;
        transform: translateX(100%); transition: transform .32s cubic-bezier(.4,0,.2,1);
        box-shadow: -8px 0 30px rgba(20,60,45,.15); overflow-y: auto;
    }
    body.nav-open .nav-main { transform: translateX(0); }
    .nav-scrim { display: none; position: fixed; inset: 0; background: rgba(10,40,30,.45); z-index: 99; }
    body.nav-open .nav-scrim { display: block; }
    body.nav-open { overflow: hidden; }

    .nav-main .nav-item { width: 100%; margin: 0; }
    .nav-main .nav-item > a {
        display: flex; justify-content: space-between; align-items: center;
        width: 100%; padding: 14px 14px; margin: 0;
        font-size: 1.02em; font-weight: 500; color: #2c3e50;
        border-bottom: 1px solid #eef4f1;
    }
    .nav-main .nav-item > a:hover, .nav-main .nav-item > a.active { background: #eaf7f1; color: #0d7a5e; }
    .nav-main .nav-item .dropdown {
        display: none; position: static; min-width: 0;
        background: #f6fbf8; border: none; box-shadow: none;
        padding: 4px 0 8px 8px; opacity: 1; visibility: visible;
        transform: none; border-radius: 0 0 10px 10px;
    }
    .nav-main .nav-item.open .dropdown { display: block; }
    .nav-main .nav-item.open > a { color: #0d7a5e; }
    .nav-main .nav-item.open > a .caret { transform: rotate(180deg); }
    .nav-main .nav-item .dropdown a {
        padding: 11px 14px; font-size: .95em;
        color: #3d6b5a; border-left: 2px solid #bfe6d6;
    }
    .nav-main .nav-item .dropdown a:hover { color: #0d7a5e; background: #e9f6ef; }
    .nav-main .nav-item .caret { transition: transform .25s; }

    .nav-item.lang-item { margin: 6px 0 0 0; width: 100%; }
    .nav-item.lang-item > a { width: 100%; text-align: center; padding: 12px 14px; font-size: 1em; }
}