/* =========================================
   ZenSpace Base Stylesheet (全局通用样式)
   ========================================= */

:root {
    --primary-color: #1c2124;
    --primary-light: #2e363a;
    --accent-color: #5b7c72;
    --bg-overlay: rgba(10, 15, 12, 0.75);
    
    --glass-bg: rgba(255, 255, 255, 0.05);
    --glass-border: rgba(255, 255, 255, 0.1);
    --glass-shadow: 0 8px 32px 0 rgba(0, 0, 0, 0.3);
    --glass-blur: blur(12px);

    --text-primary: #ffffff;
    --text-secondary: rgba(255, 255, 255, 0.65);

    --font-heading: 'Noto Serif SC', serif;
    --font-body: 'Inter', sans-serif;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: var(--font-body);
    color: var(--text-primary);
    background-color: var(--primary-color);
    line-height: 1.6;
    overflow-x: hidden;
}

/* Global Background */
.global-bg {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    z-index: -1;
    background-size: cover;
    background-position: center;
    background-color: var(--primary-color);
    transition: background-image 1s ease-in-out, background-color 1s ease-in-out;
}

.global-bg::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: var(--bg-overlay);
    transition: background-color 1s ease-in-out;
}

/* Navigation Bar */
.navbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1.5rem 4rem;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 100;
    background: linear-gradient(to bottom, rgba(0,0,0,0.9) 0%, rgba(0,0,0,0) 100%);
}

.nav-brand a {
    font-family: var(--font-heading);
    font-size: 1.8rem;
    font-weight: 600;
    letter-spacing: 2px;
    color: var(--text-primary);
    text-decoration: none;
}

.nav-brand p {
    font-size: 0.8rem;
    color: var(--text-secondary);
    letter-spacing: 1px;
}

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

.nav-links li {
    position: relative;
}

.nav-links a {
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 0.95rem;
    letter-spacing: 1px;
    transition: color 0.3s ease;
    padding-bottom: 5px;
}

.nav-links a:hover,
.nav-links a.active {
    color: var(--text-primary);
    border-bottom: 2px solid var(--accent-color);
}

/* Dropdown Menu */
.dropdown-menu {
    display: none;
    position: absolute;
    top: 100%;
    left: 50%;
    transform: translateX(-50%);
    background: rgba(20, 25, 22, 0.95);
    backdrop-filter: blur(10px);
    border: 1px solid var(--glass-border);
    border-radius: 10px;
    padding: 1rem 0;
    min-width: 150px;
    list-style: none;
    box-shadow: 0 10px 30px rgba(0,0,0,0.5);
    margin-top: 15px;
}

/* 隐形的鼠标桥接区，防止 hover 丢失 */
.dropdown-menu::before {
    content: '';
    position: absolute;
    top: -20px;
    left: 0;
    width: 100%;
    height: 20px;
    background: transparent;
}

.nav-links li:hover .dropdown-menu {
    display: block;
    animation: fadeInDown 0.3s ease;
}

.dropdown-menu li {
    padding: 0.5rem 1.5rem;
}

.dropdown-menu a {
    border-bottom: none !important;
    display: block;
    color: var(--text-secondary);
}

.dropdown-menu a:hover {
    color: var(--accent-color) !important;
}

@keyframes fadeInDown {
    from { opacity: 0; transform: translate(-50%, -10px); }
    to { opacity: 1; transform: translate(-50%, 0); }
}

/* Main Content Layout */
.page-container {
    padding-top: 120px; 
    min-height: calc(100vh - 100px);
    display: flex;
    flex-direction: column;
    align-items: center;
    padding-bottom: 4rem;
}

.glass-panel {
    background: var(--glass-bg);
    backdrop-filter: var(--glass-blur);
    -webkit-backdrop-filter: var(--glass-blur);
    border: 1px solid var(--glass-border);
    border-radius: 20px;
    box-shadow: var(--glass-shadow);
    padding: 3rem;
    width: 90%;
    max-width: 900px;
    margin-bottom: 2rem;
}

/* Section Headings */
.section-heading {
    font-family: var(--font-heading);
    font-size: 2rem;
    margin-bottom: 1.5rem;
    color: var(--text-primary);
    border-bottom: 1px solid var(--glass-border);
    padding-bottom: 0.5rem;
}

/* Generic Footer */
.site-footer {
    width: 100%;
    background: rgba(0,0,0,0.5);
    backdrop-filter: blur(5px);
    border-top: 1px solid var(--glass-border);
    padding: 3rem 0;
    margin-top: auto;
}

.footer-content {
    max-width: 900px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0 2rem;
}

.footer-info h4 {
    font-family: var(--font-heading);
    margin-bottom: 0.5rem;
    font-size: 1.2rem;
}

.footer-info p {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.footer-social {
    display: flex;
    gap: 1rem;
}

.footer-social a {
    color: var(--text-primary);
    font-size: 1.5rem;
    transition: color 0.3s;
}

.footer-social a:hover {
    color: var(--accent-color);
}

/* Responsive */
@media (max-width: 768px) {
    .navbar {
        flex-direction: column;
        padding: 1rem;
        gap: 1rem;
    }
    
    .nav-links {
        flex-wrap: wrap;
        justify-content: center;
        gap: 1rem;
    }

    .dropdown-menu {
        position: relative;
        transform: none;
        left: 0;
        margin-top: 0;
        background: transparent;
        box-shadow: none;
        border: none;
        display: none; /* Mobile dropdown needs JS or stays hidden for simplicity, will use flex wrap */
    }
    
    .footer-content {
        flex-direction: column;
        gap: 2rem;
        text-align: center;
    }
}