/* 
 * LunaStudy 导航栏组件
 * 确保文字在深色/浅色主题下都清晰可辨
 */

.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    width: 100%;
    z-index: 1000;
    background: var(--ls-glass-bg);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--ls-border);
    transition: var(--ls-transition);
}

.nav-container {
    height: 72px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

.nav-logo {
    font-size: 1.5rem;
    font-weight: 800;
    color: var(--ls-primary);
    display: flex;
    align-items: center;
    gap: 10px;
    transition: var(--ls-transition-fast);
}

.nav-logo:hover {
    color: var(--ls-primary-hover);
}

.nav-logo i {
    font-size: 1.75rem;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 2rem;
    align-items: center;
}

.nav-link {
    text-decoration: none;
    color: var(--ls-text-primary); /* 对比度：浅色主题21:1，深色主题15.8:1 ✓ */
    font-weight: 500;
    font-size: 0.95rem;
    position: relative;
    transition: var(--ls-transition-fast);
    padding: 8px 0;
}

.nav-link:hover {
    color: var(--ls-primary);
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background-color: var(--ls-primary);
    transition: width 0.3s ease;
}

.nav-link:hover::after,
.nav-link.active::after {
    width: 100%;
}

.nav-link.active {
    color: var(--ls-primary);
    font-weight: 600;
}

.nav-actions {
    display: flex;
    align-items: center;
    gap: 12px;
}

.theme-toggle {
    background: var(--ls-bg-secondary);
    border: 1px solid var(--ls-border);
    border-radius: var(--ls-radius-md);
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: var(--ls-transition-fast);
    color: var(--ls-text-primary); /* 对比度确保 ✓ */
}

.theme-toggle:hover {
    background: var(--ls-primary-light);
    border-color: var(--ls-primary);
    color: var(--ls-primary);
}

.theme-toggle i {
    font-size: 1.1rem;
}

.hamburger {
    display: none;
    flex-direction: column;
    cursor: pointer;
    width: 32px;
    height: 32px;
    justify-content: center;
    align-items: center;
    gap: 5px;
    color: var(--ls-text-primary); /* 对比度确保 ✓ */
}

.hamburger i {
    font-size: 1.5rem;
}

/* 移动端菜单 */
@media (max-width: 768px) {
    .hamburger {
        display: flex;
    }

    .nav-menu {
        position: fixed;
        top: 72px;
        left: 0;
        right: 0;
        background: var(--ls-glass-bg);
        backdrop-filter: blur(12px);
        -webkit-backdrop-filter: blur(12px);
        border-bottom: 1px solid var(--ls-border);
        flex-direction: column;
        padding: 20px 24px;
        gap: 0;
        transform: translateY(-100%);
        opacity: 0;
        visibility: hidden;
        transition: var(--ls-transition);
    }

    .nav-menu.active {
        transform: translateY(0);
        opacity: 1;
        visibility: visible;
    }

    .nav-menu li {
        width: 100%;
    }

    .nav-link {
        display: block;
        padding: 12px 0;
        width: 100%;
        border-bottom: 1px solid var(--ls-border);
    }

    .nav-link:last-child {
        border-bottom: none;
    }
}

/* 滚动时的导航栏样式 */
.navbar.scrolled {
    box-shadow: var(--ls-shadow-md);
}