/**
 * 图书检索系统 - 统一头部样式
 * 适用于: opacMain.html, bookShowInSelf.html, bookshelfLocatorWithBooks.html
 */

/* ========== CSS 变量定义 ========== */
:root {
    --header-bg: #1a202c;
    --header-height: 64px;
    --header-text-color: #ffffff;
    --header-accent-color: #f97316;
    --header-hover-color: #fdba74;
    --header-border-color: rgba(255, 255, 255, 0.1);
}

/* ========== Header 基础样式 ========== */
.opac-header {
    background-color: var(--header-bg);
    color: var(--header-text-color);
    height: var(--header-height);
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
    position: relative;
    z-index: 1000;
}

.opac-header .header-container {
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 1rem;
    height: 100%;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

/* ========== Logo 区域 ========== */
.opac-header .header-brand {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    text-decoration: none;
    color: var(--header-text-color);
    height: 100%;
}

.opac-header .header-brand .brand-icon {
    font-size: 1.5rem;
    color: var(--header-accent-color);
}

.opac-header .header-brand .brand-title {
    font-size: 1.5rem;
    font-weight: 700;
    letter-spacing: -0.025em;
}

/* 返回按钮 */
.opac-header .header-back-btn {
    background: none;
    border: none;
    color: var(--header-text-color);
    font-size: 1.25rem;
    cursor: pointer;
    padding: 0.5rem;
    margin-right: 0.5rem;
    border-radius: 0.375rem;
    transition: all 0.2s;
    display: flex;
    align-items: center;
    justify-content: center;
}

.opac-header .header-back-btn:hover {
    color: var(--header-hover-color);
    background-color: rgba(255, 255, 255, 0.1);
}

/* ========== 导航菜单 ========== */
.opac-header .header-nav {
    display: flex;
    align-items: center;
    gap: 2rem;
    height: 100%;
}

.opac-header .header-nav .nav-link,
.opac-header .header-nav .nav-link:link,
.opac-header .header-nav .nav-link:visited {
    color: var(--header-text-color) !important;
    text-decoration: none !important;
    font-size: 0.95rem;
    font-weight: 500;
    padding: 0 0 0.25rem 0;
    margin: 0;
    border-bottom: 2px solid transparent;
    transition: all 0.2s;
    display: flex;
    align-items: center;
    gap: 0.375rem;
    white-space: nowrap;
    line-height: 1;
    background: none !important;
    box-sizing: border-box;
}

.opac-header .header-nav .nav-link:hover,
.opac-header .header-nav .nav-link:focus {
    color: var(--header-hover-color) !important;
    text-decoration: none !important;
    background: none !important;
}

.opac-header .header-nav .nav-link.active,
.opac-header .header-nav .nav-link.active:hover,
.opac-header .header-nav .nav-link.active:focus {
    color: var(--header-accent-color) !important;
    border-bottom-color: var(--header-accent-color);
    background: none !important;
}

.opac-header .header-nav .nav-link i {
    font-size: 0.875rem;
    display: inline-flex;
    align-items: center;
}

/* ========== 语言切换器 ========== */
.opac-header .lang-switcher {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    margin-left: 1.5rem;
    padding-left: 1.5rem;
    border-left: 1px solid var(--header-border-color);
}

.opac-header .lang-switcher .lang-btn {
    background: none;
    border: 1px solid rgba(255, 255, 255, 0.3);
    color: var(--header-text-color);
    padding: 0.25rem 0.625rem;
    border-radius: 0.25rem;
    cursor: pointer;
    font-size: 0.8125rem;
    font-weight: 500;
    transition: all 0.2s;
    min-width: 2rem;
}

.opac-header .lang-switcher .lang-btn:hover {
    background-color: rgba(255, 255, 255, 0.1);
    border-color: rgba(255, 255, 255, 0.5);
}

.opac-header .lang-switcher .lang-btn.active {
    background-color: var(--header-accent-color);
    border-color: var(--header-accent-color);
    color: white;
}

/* ========== 移动端菜单按钮 ========== */
.opac-header .mobile-menu-btn {
    display: none;
    background: none;
    border: none;
    color: var(--header-text-color);
    font-size: 1.25rem;
    cursor: pointer;
    padding: 0.5rem;
    border-radius: 0.375rem;
    transition: all 0.2s;
}

.opac-header .mobile-menu-btn:hover {
    background-color: rgba(255, 255, 255, 0.1);
}

/* ========== 移动端导航菜单 ========== */
.opac-header .mobile-nav {
    display: none;
    position: absolute;
    top: var(--header-height);
    left: 0;
    right: 0;
    background-color: var(--header-bg);
    padding: 1rem;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    border-top: 1px solid var(--header-border-color);
}

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

.opac-header .mobile-nav .nav-link {
    display: block;
    padding: 0.75rem 1rem;
    color: var(--header-text-color);
    text-decoration: none;
    border-radius: 0.375rem;
    transition: all 0.2s;
}

.opac-header .mobile-nav .nav-link:hover {
    background-color: rgba(255, 255, 255, 0.1);
}

.opac-header .mobile-nav .nav-link.active {
    color: var(--header-accent-color);
    background-color: rgba(249, 115, 22, 0.1);
}

.opac-header .mobile-nav .lang-switcher {
    margin: 0.75rem 1rem;
    padding: 0.75rem 0;
    border-left: none;
    border-top: 1px solid var(--header-border-color);
    justify-content: center;
}

/* ========== 响应式设计 ========== */
@media (max-width: 768px) {
    .opac-header .header-nav {
        display: none;
    }

    .opac-header .mobile-menu-btn {
        display: block;
    }

    .opac-header .header-brand .brand-title {
        font-size: 1.25rem;
    }
}

@media (min-width: 769px) {
    .opac-header .mobile-nav {
        display: none !important;
    }
}

/* ========== 辅助类 ========== */
.opac-header .flex {
    display: flex;
}

.opac-header .items-center {
    align-items: center;
}

.opac-header .gap-2 {
    gap: 0.5rem;
}

.opac-header .hidden {
    display: none;
}