/* --- 导航栏 --- */
nav {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 50;
    padding: 40px 0;
    transition: all 0.7s ease;
}

nav.scrolled {
    padding: 15px 0;
    background: var(--nav-bg);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border-light);
}

.nav-container {
    max-width: 1152px;
    margin: 0 auto;
    padding: 0 32px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo-group {
    display: flex;
    align-items: center;
    gap: 16px;
    cursor: pointer;
}

.logo-en {
    font-family: var(--font-script);
    font-size: 32px;
    line-height: 1;
    color: var(--ink-heavy);
}

.logo-divider {
    width: 1px;
    height: 20px;
    background-color: var(--ink-faint);
}

.logo-zh {
    font-family: var(--font-brush);
    font-size: 18px;
    letter-spacing: 0.3em;
    color: var(--ink-medium);
    margin-top: 2px;
}

.nav-links {
    display: none;
    align-items: center;
    gap: 48px;
    font-size: 11px;
    letter-spacing: 0.3em;
    text-transform: uppercase;
    color: var(--ink-light);
}

@media (min-width: 768px) {
    .nav-links { display: flex; }
}

.nav-links a {
    position: relative;
    transition: color 0.5s ease;
}

.nav-links a:hover { color: var(--ink-heavy); }
.nav-links a::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 0;
    height: 1px;
    background-color: var(--ink-heavy);
    transition: width 0.5s ease;
}
.nav-links a:hover::after { width: 100%; }

/* --- 导航右侧（链接 + 主题按钮 + 汉堡） --- */
.nav-right {
    display: flex;
    align-items: center;
    gap: 14px;
}

/* --- 主题切换按钮 --- */
.theme-toggle {
    width: 36px;
    height: 36px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    border: 1px solid var(--border-color);
    border-radius: 50%;
    color: var(--ink-medium);
    background: transparent;
    cursor: pointer;
    padding: 0;
    transition: color 0.4s ease, border-color 0.4s ease,
        background-color 0.4s ease;
}
.theme-toggle:hover {
    color: var(--ink-heavy);
    border-color: var(--ink-heavy);
}
.theme-toggle .icon { display: none; }
:root[data-theme='light'] .theme-toggle .icon-moon { display: block; }
:root[data-theme='dark']  .theme-toggle .icon-sun  { display: block; }
.theme-toggle.in-menu {
    width: 44px;
    height: 44px;
}

/* --- 汉堡菜单 --- */
.hamburger {
    display: none;
    background: none;
    border: none;
    cursor: pointer;
    padding: 8px;
    color: var(--ink-dark);
}
@media (max-width: 767px) {
    .hamburger { display: block; }
}

/* --- 移动端全屏菜单 --- */
.mobile-menu {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: var(--mobile-menu-bg);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    z-index: 60;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 48px;
}
.mobile-menu.open { display: flex; }
.mobile-menu a {
    font-family: var(--font-brush);
    font-size: 28px;
    letter-spacing: 0.15em;
    color: var(--ink-dark);
    transition: color 0.3s ease;
}
.mobile-menu a:hover { color: var(--ink-heavy); }
.mobile-menu-close {
    position: absolute;
    top: 32px;
    right: 32px;
    background: none;
    border: none;
    cursor: pointer;
    color: var(--ink-dark);
    padding: 8px;
}

@media (max-width: 767px) {
    nav {
        padding: 24px 0;
    }

    nav.scrolled {
        padding: 10px 0;
    }

    .nav-container {
        padding: 0 22px;
    }

    .logo-en {
        font-size: 28px;
    }

    .logo-zh {
        font-size: 16px;
    }
}