/* ============================================
   版心 / 头部 / 页脚
   ============================================ */

:root {
    --site-content-width: 760px;
    --nav-height: 68px;
}

/* ---------- 头部：静态窄条，细线收边 ---------- */
.site-nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 100;
    background-color: var(--nav-bg);
    border-bottom: 1px solid var(--accent-subtle);
    transform: translateY(0);
    transition: transform 0.32s ease, background-color 0.3s ease, border-color 0.3s ease;
}

.site-nav.nav-hidden {
    transform: translateY(-100%);
}

.nav-inner {
    position: relative;
    width: min(100% - 48px, 1080px);
    height: var(--nav-height);
    margin: 0 auto;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 24px;
}

.logo {
    font-family: var(--font-serif);
    font-size: 1.16rem;
    font-weight: 600;
    letter-spacing: 0.04em;
    color: var(--text-primary);
}

.logo a {
    color: inherit;
    text-decoration: none;
    transition: color 0.2s ease;
}

.logo a:hover {
    color: var(--accent-strong);
}

/* ---------- 导航链接 ---------- */
.menu-links {
    display: flex;
    align-items: center;
    gap: 26px;
}

.menu-links > a {
    position: relative;
    display: inline-flex;
    align-items: center;
    padding: 4px 0;
    font-family: var(--font-mono);
    font-size: 0.78rem;
    font-weight: 500;
    letter-spacing: 0.06em;
    color: var(--text-primary);
    text-decoration: none;
    white-space: nowrap;
    transition: color 0.2s ease;
}

.menu-links > a::after {
    content: "";
    position: absolute;
    left: 0;
    right: 0;
    bottom: -3px;
    height: 1px;
    background-color: var(--accent-color);
    transform: scaleX(0);
    transform-origin: left center;
    transition: transform 0.28s ease;
}

.menu-links > a:hover,
.menu-links > a.active {
    color: var(--accent-strong);
}

.menu-links > a:hover::after,
.menu-links > a.active::after {
    transform: scaleX(1);
}

.menu-links .nav-rss {
    gap: 6px;
    color: var(--text-secondary);
}

.menu-links .nav-rss svg {
    flex: none;
}

/* ---------- 主题切换 ---------- */
.theme-toggle {
    position: relative;
    width: 34px;
    height: 34px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    border: 1px solid var(--accent-subtle);
    border-radius: 2px;
    background-color: transparent;
    color: var(--text-primary);
    transition: border-color 0.2s ease, color 0.2s ease, background-color 0.2s ease;
}

.theme-toggle:hover {
    border-color: var(--text-secondary);
    color: var(--text-primary);
    background-color: transparent;
}

.theme-toggle .icon-sun,
.theme-toggle .icon-moon {
    position: absolute;
    transition: opacity 0.25s ease, transform 0.25s ease;
}

.theme-toggle .icon-sun {
    opacity: 0;
    transform: rotate(-35deg) scale(0.7);
}

.theme-toggle .icon-moon {
    opacity: 1;
    transform: rotate(0) scale(1);
}

[data-theme="dark"] .theme-toggle .icon-sun {
    opacity: 1;
    transform: rotate(0) scale(1);
}

[data-theme="dark"] .theme-toggle .icon-moon {
    opacity: 0;
    transform: rotate(35deg) scale(0.7);
}

/* ---------- 汉堡按钮 ---------- */
.menu-toggle {
    display: none;
    width: 36px;
    height: 36px;
    padding: 0;
    border: 0;
    background: transparent;
    color: var(--text-primary);
    align-items: center;
    justify-content: center;
}

.hamburger-box {
    position: relative;
    display: block;
    width: 20px;
    height: 12px;
}

.hamburger-inner,
.hamburger-inner::before,
.hamburger-inner::after {
    position: absolute;
    left: 0;
    width: 100%;
    height: 1px;
    background-color: currentColor;
    transition: transform 0.25s ease, opacity 0.2s ease, top 0.25s ease;
}

.hamburger-inner {
    top: 5px;
}

.hamburger-inner::before {
    content: "";
    top: -5px;
}

.hamburger-inner::after {
    content: "";
    top: 5px;
}

.site-nav.menu-open .hamburger-inner {
    background-color: transparent;
}

.site-nav.menu-open .hamburger-inner::before {
    top: 0;
    transform: rotate(45deg);
}

.site-nav.menu-open .hamburger-inner::after {
    top: 0;
    transform: rotate(-45deg);
}

/* ---------- 主体版心 ---------- */
.site-main {
    width: min(100% - 48px, 1080px);
    margin: 0 auto;
    padding-top: calc(var(--nav-height) + 64px);
    padding-bottom: 96px;
}

/* ---------- 移动端抽屉 ---------- */
.menu-overlay {
    display: none;
}

@media (max-width: 768px) {
    :root {
        --nav-height: 60px;
    }

    .menu-toggle {
        display: inline-flex;
    }

    .menu-links {
        position: fixed;
        top: var(--nav-height);
        left: 0;
        right: 0;
        z-index: 99;
        flex-direction: column;
        align-items: stretch;
        gap: 0;
        padding: 8px 24px 24px;
        background-color: var(--bg-color);
        border-bottom: 1px solid var(--accent-subtle);
        transform: translateY(-12px);
        opacity: 0;
        visibility: hidden;
        pointer-events: none;
        transition: transform 0.24s ease, opacity 0.2s ease, visibility 0.2s;
    }

    .site-nav.menu-open .menu-links {
        transform: translateY(0);
        opacity: 1;
        visibility: visible;
        pointer-events: auto;
    }

    .menu-links > a {
        padding: 15px 0;
        font-size: 0.76rem;
        border-bottom: 1px solid var(--accent-subtle);
    }

    .menu-links > a::after {
        display: none;
    }

    .menu-links > a.active {
        color: var(--accent-color);
    }

    .theme-toggle {
        margin-top: 18px;
        align-self: flex-start;
        width: 38px;
        height: 38px;
    }

    .menu-overlay {
        display: block;
        position: fixed;
        inset: var(--nav-height) 0 0;
        z-index: 98;
        background-color: rgba(18, 18, 18, 0.28);
        opacity: 0;
        visibility: hidden;
        pointer-events: none;
        transition: opacity 0.24s ease, visibility 0.2s;
    }

    .site-nav.menu-open .menu-overlay {
        opacity: 1;
        visibility: visible;
        pointer-events: auto;
    }

    .site-main {
        width: min(100% - 40px, 1080px);
        padding-top: calc(var(--nav-height) + 40px);
        padding-bottom: 72px;
    }

    body.menu-open-active {
        overflow: hidden;
    }
}

@media (max-width: 480px) {
    .site-main {
        width: calc(100% - 32px);
    }
}