/* ==========================================================================
   新芮表单 公共顶部导航样式
   首页 / 关于页 / 资讯页 共用，保证头部完全一致（单点维护）
   ========================================================================== */

/* 导航依赖的基础变量（独立定义，避免各页面 :root 差异） */
:root {
    --sn-primary: #2563eb;
    --sn-primary-dark: #1d4ed8;
    --sn-primary-light: #3b82f6;
    --sn-primary-50: #eff6ff;
    --sn-primary-100: #dbeafe;
    --sn-dark: #1e293b;
    --sn-text: #334155;
    --sn-text-light: #64748b;
    --sn-white: #ffffff;
    --sn-border: #e2e8f0;
    --sn-gradient: linear-gradient(135deg, #2563eb 0%, #1d4ed8 50%, #1e40af 100%);
    --sn-shadow-sm: 0 1px 2px 0 rgba(0,0,0,0.05);
    --sn-shadow: 0 4px 6px -1px rgba(0,0,0,0.07), 0 2px 4px -2px rgba(0,0,0,0.05);
    --sn-shadow-md: 0 10px 15px -3px rgba(0,0,0,0.08), 0 4px 6px -4px rgba(0,0,0,0.04);
    --sn-transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

/* ============ 顶部导航容器 ============ */
.sn-site-header,
.site-header {
    position: sticky;
    top: 0;
    z-index: 1000;
    background: var(--sn-white);
    border-bottom: 1px solid var(--sn-border);
    box-shadow: var(--sn-shadow-sm);
    width: 100%;
}

.sn-header-inner,
.header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 68px;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* ============ Logo ============ */
.sn-logo-block,
.logo-block {
    flex-shrink: 0;
}

.sn-logo-link,
.logo-link {
    display: flex;
    align-items: center;
    gap: 10px;
    text-decoration: none;
}

.sn-logo-img,
.logo-img {
    width: 36px;
    height: 36px;
    border-radius: 8px;
    object-fit: cover;
    display: block;
}

.sn-logo-text,
.logo-text {
    font-size: 1.35rem;
    font-weight: 700;
    color: var(--sn-dark);
    letter-spacing: 0.5px;
    line-height: 1;
}

/* ============ 导航菜单 ============ */
.sn-main-nav,
.main-nav {
    flex: 1;
    margin-left: 40px;
}

.sn-nav-list,
.nav-list {
    display: flex;
    gap: 32px;
    margin: 0;
    padding: 0;
    list-style: none;
}

.sn-nav-list li,
.nav-list li {
    list-style: none;
}

.sn-nav-list a,
.nav-list a {
    font-size: 0.95rem;
    font-weight: 500;
    color: var(--sn-text);
    padding: 8px 0;
    position: relative;
    text-decoration: none;
    display: block;
    transition: var(--sn-transition);
}

.sn-nav-list a::after,
.nav-list a::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--sn-primary);
    border-radius: 2px;
    transition: var(--sn-transition);
}

.sn-nav-list a:hover,
.sn-nav-list a.active,
.nav-list a:hover,
.nav-list a.active {
    color: var(--sn-primary);
}

.sn-nav-list a:hover::after,
.sn-nav-list a.active::after,
.nav-list a:hover::after,
.nav-list a.active::after {
    width: 100%;
}

/* ============ 下拉菜单（更多） ============ */
.nav-has-dropdown {
    position: relative;
}

.nav-dropdown-toggle {
    cursor: pointer;
}

.nav-dropdown {
    position: absolute;
    top: 100%;
    left: 50%;
    transform: translateX(-50%) translateY(8px);
    min-width: 180px;
    background: var(--sn-white);
    border: 1px solid var(--sn-border);
    border-radius: 10px;
    box-shadow: 0 10px 25px -5px rgba(0,0,0,0.15);
    padding: 8px;
    opacity: 0;
    visibility: hidden;
    transition: var(--sn-transition);
    z-index: 1200;
    flex-direction: column;
    gap: 2px;
}

.nav-has-dropdown:hover .nav-dropdown,
.nav-has-dropdown.open .nav-dropdown {
    opacity: 1;
    visibility: visible;
    transform: translateX(-50%) translateY(0);
}

.nav-dropdown li {
    list-style: none;
}

.nav-dropdown a {
    display: block;
    padding: 10px 14px;
    font-size: 0.88rem;
    font-weight: 500;
    color: var(--sn-text);
    border-radius: 6px;
    text-decoration: none;
    transition: var(--sn-transition);
    white-space: nowrap;
}

.nav-dropdown a:hover {
    background: var(--sn-primary-50);
    color: var(--sn-primary);
}

.nav-dropdown a::after {
    display: none;
}

/* ============ 右侧操作按钮 ============ */
.sn-header-actions,
.header-actions {
    display: flex;
    align-items: center;
    gap: 12px;
    flex-shrink: 0;
}

.sn-btn-login,
.btn-login {
    padding: 8px 20px;
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--sn-primary);
    border: 1px solid var(--sn-primary-100);
    background: var(--sn-primary-50);
    border-radius: 8px;
    transition: var(--sn-transition);
    cursor: pointer;
    text-decoration: none;
    line-height: 1.4;
    display: inline-flex;
    align-items: center;
    justify-content: center;
}

.sn-btn-login:hover,
.btn-login:hover {
    background: var(--sn-primary-100);
    color: var(--sn-primary-dark);
}

.sn-btn-free,
.btn-free {
    padding: 8px 22px;
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--sn-white);
    background: var(--sn-gradient);
    border: none;
    border-radius: 8px;
    box-shadow: var(--sn-shadow);
    transition: var(--sn-transition);
    cursor: pointer;
    text-decoration: none;
    line-height: 1.4;
    display: inline-flex;
    align-items: center;
    justify-content: center;
}

.sn-btn-free:hover,
.btn-free:hover {
    transform: translateY(-2px);
    box-shadow: var(--sn-shadow-md);
    opacity: 0.95;
}

/* ============ 移动端汉堡菜单按钮 ============ */
.sn-nav-toggle,
.nav-toggle {
    display: none;
    flex-direction: column;
    justify-content: center;
    gap: 5px;
    width: 40px;
    height: 40px;
    background: transparent;
    border: none;
    cursor: pointer;
    padding: 8px;
}

.sn-nav-toggle span,
.nav-toggle span {
    display: block;
    height: 2px;
    width: 100%;
    background: var(--sn-dark);
    border-radius: 2px;
    transition: var(--sn-transition);
}

.sn-nav-toggle.active span:nth-child(1),
.nav-toggle.active span:nth-child(1) {
    transform: translateY(7px) rotate(45deg);
}
.sn-nav-toggle.active span:nth-child(2),
.nav-toggle.active span:nth-child(2) {
    opacity: 0;
}
.sn-nav-toggle.active span:nth-child(3),
.nav-toggle.active span:nth-child(3) {
    transform: translateY(-7px) rotate(-45deg);
}

/* ============ 响应式 ============ */
@media (max-width: 768px) {
    .sn-nav-toggle,
    .nav-toggle {
        display: flex;
    }

    .sn-main-nav,
    .main-nav {
        position: fixed;
        top: 68px;
        left: 0;
        right: 0;
        background: var(--sn-white);
        margin: 0;
        padding: 16px 20px;
        box-shadow: var(--sn-shadow-md);
        transform: translateY(-120%);
        transition: var(--sn-transition);
        opacity: 0;
        z-index: 999;
        border-bottom: 1px solid var(--sn-border);
    }

    .sn-main-nav.open,
    .main-nav.open {
        transform: translateY(0);
        opacity: 1;
    }

    .sn-nav-list,
    .nav-list {
        flex-direction: column;
        gap: 0;
    }

    .sn-nav-list li,
    .nav-list li {
        border-bottom: 1px solid var(--sn-border);
    }

    .sn-nav-list li:last-child,
    .nav-list li:last-child {
        border-bottom: none;
    }

    .sn-nav-list a,
    .nav-list a {
        display: block;
        padding: 14px 0;
        font-size: 1rem;
    }

    /* 移动端下拉菜单：改为内联展开 */
    .nav-has-dropdown {
        position: static;
    }

    .nav-dropdown {
        position: static;
        transform: none;
        box-shadow: none;
        border: none;
        border-left: 2px solid var(--sn-primary-100);
        margin-left: 16px;
        padding: 0 0 0 8px;
        min-width: 0;
        border-radius: 0;
        display: none;
        opacity: 1;
        visibility: visible;
    }

    .nav-has-dropdown.open .nav-dropdown {
        display: block;
        transform: none;
    }

    .nav-dropdown a {
        padding: 10px 0;
        font-size: 0.92rem;
    }
}

@media (max-width: 576px) {
    .sn-header-actions .sn-btn-login,
    .header-actions .btn-login {
        display: none;
    }

    .sn-btn-free,
    .btn-free {
        padding: 8px 18px;
        font-size: 0.85rem;
    }
}