:root {
    --site-nav-primary: #2563eb;
    --site-nav-primary-hover: #1d4ed8;
    --site-nav-text: #334155;
    --site-nav-accent: #f472b6;
    --site-nav-accent-soft: rgba(244, 114, 182, 0.9);
    --site-nav-max: 1200px;
    --site-nav-pad-x: 1.5rem;
    --site-nav-height: 72px;
}

.site-header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1030;
    height: var(--site-nav-height);
    transition: background-color 0.3s ease, box-shadow 0.3s ease, backdrop-filter 0.3s ease;
}

.site-header--solid,
.site-header.is-scrolled {
    background: rgba(255, 255, 255, 0.92);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    box-shadow: 0 4px 24px rgba(15, 23, 42, 0.08);
}

.site-header--portal {
    background: transparent;
    box-shadow: none;
}

.site-nav-shell {
    width: 100%;
    max-width: var(--site-nav-max);
    height: 100%;
    margin: 0 auto;
    padding: 0 var(--site-nav-pad-x);
    box-sizing: border-box;
}

.site-nav-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
    height: 100%;
    width: 100%;
}

.site-nav-brand {
    display: inline-flex;
    align-items: center;
    flex-shrink: 0;
    text-decoration: none;
    line-height: 0;
    transition: opacity 0.2s ease, transform 0.2s ease;
    cursor: pointer;
}

.site-nav-brand.router-link-active {
    /* 品牌仅作回首页，不与「当前页」导航高亮混淆 */
    opacity: 1;
}

.site-nav-brand:hover {
    opacity: 0.92;
    transform: translateY(-1px);
}

.site-nav-brand-logo {
    display: block;
    height: 40px;
    width: auto;
    max-width: 180px;
    object-fit: contain;
}

.site-nav-brand-text {
    display: inline-flex;
    align-items: center;
    font-size: 1.05rem;
    font-weight: 700;
    color: var(--site-nav-text);
    line-height: 1.2;
    white-space: nowrap;
}

.site-nav-desktop {
    display: none;
    align-items: center;
    justify-content: flex-end;
    flex: 1 1 auto;
    gap: 0.15rem;
    min-width: 0;
}

@media (min-width: 900px) {
    .site-nav-desktop {
        display: flex;
    }

    .site-nav-toggle {
        display: none !important;
    }
}

.site-nav-link {
    color: var(--site-nav-text);
    text-decoration: none;
    padding: 0.45rem 0.7rem;
    font-size: 0.92rem;
    font-weight: 500;
    white-space: nowrap;
    border-radius: 999px;
    transition: background-color 0.2s ease, color 0.2s ease, transform 0.2s cubic-bezier(0.22, 1, 0.36, 1);
}

.site-nav-link:hover {
    transform: translateY(-1px);
}

.site-nav-link:hover,
.site-nav-link.active {
    color: var(--site-nav-primary);
    background: rgba(37, 99, 235, 0.08);
}

.site-nav-icon-link {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 2.25rem;
    height: 2.25rem;
    border: 1px solid var(--site-border, rgba(15, 23, 42, 0.1));
    border-radius: 999px;
    background: rgba(255, 255, 255, 0.65);
    color: var(--site-nav-text);
    text-decoration: none;
    transition: background-color 0.2s ease, color 0.2s ease, transform 0.2s ease;
}

.site-nav-icon-link:hover {
    color: var(--site-nav-primary);
    transform: scale(1.05);
}

html[data-site-theme="dusk"] .site-nav-icon-link {
    background: rgba(30, 41, 59, 0.85);
    border-color: rgba(148, 163, 184, 0.2);
    color: #e2e8f0;
}

.site-header--portal .site-nav-icon-link,
.site-header:not(.site-header--solid):not(.is-scrolled) .site-nav-icon-link {
    background: rgba(255, 255, 255, 0.15);
    border-color: rgba(255, 255, 255, 0.25);
    color: rgba(255, 255, 255, 0.92);
}

.site-nav-social {
    display: inline-flex;
    align-items: center;
    gap: 0.35rem;
    margin-left: 0.15rem;
}

.site-nav-icon-link--brand {
    padding: 0;
}

.site-nav-icon-link .site-social-icon,
.site-nav-icon-link--brand .site-social-icon {
    display: block;
    width: 1.125rem;
    height: 1.125rem;
    object-fit: contain;
}

.site-theme-toggle .site-ui-icon {
    display: block;
    width: 1.125rem;
    height: 1.125rem;
    object-fit: contain;
}

html[data-site-theme="dusk"] .site-header--solid .site-theme-toggle .site-ui-icon {
    filter: brightness(0) saturate(100%) invert(88%);
}

html[data-site-theme="dusk"] .site-header--solid .site-nav-social .site-social-icon[src*="github"] {
    filter: brightness(0) saturate(100%) invert(88%);
}

.site-theme-toggle {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 2.25rem;
    height: 2.25rem;
    padding: 0;
    border: 1px solid var(--site-border, rgba(15, 23, 42, 0.1));
    border-radius: 999px;
    background: rgba(255, 255, 255, 0.65);
    color: var(--site-nav-text);
    cursor: pointer;
    transition: background-color 0.2s ease, color 0.2s ease, transform 0.2s ease;
}

.site-theme-toggle:hover {
    color: var(--site-nav-primary);
    transform: scale(1.05);
}

.site-theme-toggle--block {
    width: 100%;
    height: auto;
    padding: 0.65rem 1rem;
    border-radius: 0.65rem;
    font-size: 0.9rem;
    font-weight: 500;
}

html[data-site-theme="dusk"] .site-theme-toggle {
    background: rgba(30, 41, 59, 0.85);
    border-color: rgba(148, 163, 184, 0.2);
    color: #e2e8f0;
}

.site-nav-login {
    margin-left: 0.35rem;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
    min-width: 3.5rem;
    height: 2.35rem;
    padding: 0 0.95rem;
    border-radius: 999px;
    background: var(--site-nav-accent-soft);
    color: #fff;
    text-decoration: none;
    font-weight: 600;
    font-size: 0.9rem;
    box-shadow: 0 8px 24px rgba(244, 114, 182, 0.28);
    transition: transform 0.2s ease, filter 0.2s ease;
}

.site-nav-login:hover,
.site-nav-login.active {
    color: #fff;
    transform: translateY(-1px);
    filter: brightness(1.05);
}

.site-nav-login--block {
    margin: 0.5rem auto 0;
    width: fit-content;
}

.site-nav-avatar {
    margin-left: 0.35rem;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
    width: 2.35rem;
    height: 2.35rem;
    border-radius: 50%;
    overflow: hidden;
    text-decoration: none;
    border: 2px solid rgba(255, 255, 255, 0.85);
    box-shadow: 0 6px 18px rgba(15, 23, 42, 0.16);
    background: #e2e8f0;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.site-nav-avatar:hover,
.site-nav-avatar.active {
    transform: translateY(-1px);
    box-shadow: 0 10px 22px rgba(15, 23, 42, 0.22);
}

.site-nav-avatar img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    display: block;
}

.site-nav-avatar-fallback {
    width: 100%;
    height: 100%;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(145deg, #2563eb, #0ea5e9);
    color: #fff;
    font-weight: 700;
    font-size: 0.95rem;
}

.site-nav-login--block.site-nav-avatar {
    margin: 0.5rem auto 0;
}

.site-nav-toggle {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
    width: 2.5rem;
    height: 2.5rem;
    border: none;
    border-radius: 0.75rem;
    background: rgba(15, 23, 42, 0.06);
    color: var(--site-nav-text);
    font-size: 1.35rem;
    cursor: pointer;
    transition: background-color 0.2s ease;
}

.site-nav-toggle:hover {
    background: rgba(15, 23, 42, 0.1);
}

.site-nav-toggle .hidden {
    display: none;
}

.site-nav-mobile {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: rgba(255, 255, 255, 0.96);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-top: 1px solid rgba(15, 23, 42, 0.08);
    box-shadow: 0 12px 32px rgba(15, 23, 42, 0.12);
}

.site-nav-mobile.is-open {
    display: block;
}

.site-nav-mobile .site-nav-shell {
    height: auto;
    padding-top: 0.85rem;
    padding-bottom: 1rem;
}

.site-nav-mobile-links {
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
}

.site-nav-mobile .site-nav-link {
    display: block;
    text-align: center;
    padding: 0.75rem 1rem;
}

.site-nav-link--social {
    display: inline-flex !important;
    align-items: center;
    justify-content: center;
    gap: 0.45rem;
}

.visually-hidden {
    position: absolute !important;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

body.has-site-header:not(:has(.site-scroll)) {
    padding-top: var(--site-nav-height);
}

/* Portal / transparent homepage: light nav on dark imagery */
.site-header--portal .site-nav-link,
.site-header:not(.site-header--solid):not(.is-scrolled) .site-nav-link {
    color: rgba(255, 255, 255, 0.92);
}

.site-header--portal .site-nav-link:hover,
.site-header--portal .site-nav-link.active,
.site-header:not(.site-header--solid):not(.is-scrolled) .site-nav-link:hover,
.site-header:not(.site-header--solid):not(.is-scrolled) .site-nav-link.active {
    color: #fff;
    background: rgba(255, 255, 255, 0.14);
}

.site-header--portal .site-theme-toggle,
.site-header:not(.site-header--solid):not(.is-scrolled) .site-theme-toggle {
    background: rgba(255, 255, 255, 0.15);
    border-color: rgba(255, 255, 255, 0.25);
    color: rgba(255, 255, 255, 0.92);
}

.site-header--portal .site-nav-toggle,
.site-header:not(.site-header--solid):not(.is-scrolled) .site-nav-toggle {
    background: rgba(255, 255, 255, 0.14);
    color: #fff;
}

.site-header--portal .site-nav-brand-logo {
    filter: drop-shadow(0 2px 10px rgba(0, 0, 0, 0.35));
}

.site-header--portal .site-nav-mobile {
    background: rgba(15, 23, 42, 0.88);
    border-top-color: rgba(255, 255, 255, 0.1);
}

.site-header--portal .site-nav-mobile .site-nav-link {
    color: rgba(255, 255, 255, 0.92);
}

.site-header--portal .site-nav-mobile .site-nav-link:hover,
.site-header--portal .site-nav-mobile .site-nav-link.active {
    color: #fff;
    background: rgba(255, 255, 255, 0.12);
}