:root {
    --nav-btn-font-size: 12.48px;
    --nav-btn-font-weight: 700;
    --nav-btn-height: 32px;
    --nav-btn-padding: 0 12px;
    --nav-btn-radius: 9px;
    --nav-btn-gap: 6px;
    --nav-drop-font-size: 12.48px;
    --nav-drop-font-weight: 700;
    --nav-drop-padding: 9px 14px;
    --nav-shell-bg: rgba(255, 255, 255, .96);
    --nav-shell-line: #e2e8f0;
    --nav-surface: #ffffff;
    --nav-surface-hover: #f8fafc;
    --nav-text: #475569;
    --nav-text-strong: #0f172a;
    --nav-active-bg: linear-gradient(135deg, #1e293b, #334155);
    --nav-active-text: #ffffff;
    --nav-brand-accent: #3b82f6;
    --nav-user-accent: #f59e0b;
    --nav-menu-shadow: 0 12px 32px rgba(15, 23, 42, .14);
    /* Deliberately NOT var(--fb): pages disagree on --fb (the whiteboard pages
       use an SF Pro / PingFang stack), which would reintroduce glyph-width
       drift in the nav even at an identical font-size. */
    --nav-font: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Microsoft YaHei', Arial, sans-serif;
}

/* HomeTagManager is the visual reference for the whole site. nav-auth adds
   .common-nav-shell / .common-nav-logo at runtime so pages may keep their own
   content layout while the complete navigation chrome comes from one source. */
.common-nav-shell {
    display: flex;
    align-items: center;
    gap: 16px;
    background: var(--nav-shell-bg);
    border-bottom: 1px solid var(--nav-shell-line);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
}
.common-nav-shell.common-nav-shell {
    background: var(--nav-shell-bg) !important;
    border-bottom-color: var(--nav-shell-line) !important;
}
.common-nav-logo {
    flex: 0 0 auto;
    margin: 0;
    padding: 0;
    border: 0;
    background: transparent;
    color: var(--nav-text-strong);
    font-family: var(--nav-font);
    font-size: 1.1rem;
    font-weight: 800;
    line-height: 1;
    letter-spacing: -.02em;
    cursor: pointer;
    user-select: none;
}
/* Header branding must not inherit page-specific logo skins or root rem sizes.
   This sheet is loaded in <head>, before any legacy placeholder can be painted. */
[data-site-brand],
.common-nav-shell .common-nav-logo {
    font-family: var(--nav-font) !important;
    font-size: 17.6px !important;
    font-weight: 800 !important;
    font-style: normal !important;
    line-height: 1 !important;
    letter-spacing: -.352px !important;
    color: var(--nav-text-strong) !important;
    text-decoration: none !important;
    text-transform: none !important;
    text-shadow: none !important;
    white-space: nowrap;
}
[data-site-brand]:not([data-site-brand-ready]) {
    visibility: hidden !important;
    min-width: 4em;
}
.common-nav-shell .common-nav-logo em,
.common-nav-shell .common-nav-logo span {
    color: var(--nav-brand-accent);
    font-style: normal;
}
#commonNavArea {
    display: flex;
    align-items: center;
    gap: 10px;
    flex: 1 1 auto;
    min-width: 0;
}
@media (min-width: 781px) {
    .common-nav-shell {
        min-height: 62px;
        padding-left: 24px;
        padding-right: 24px;
    }
    #commonNavArea {
        overflow: visible;
    }
}
@media (max-width: 780px) {
    .common-nav-shell .common-nav-logo {
        display: none !important;
    }
    .common-nav-shell {
        display: flex !important;
        gap: 0 !important;
        padding-left: 12px !important;
        padding-right: 12px !important;
    }
    .common-nav-shell #commonNavArea {
        grid-column: 1 / -1 !important;
        width: 100% !important;
        max-width: 100% !important;
        flex: 1 1 100% !important;
    }
}
/* Authoritative nav visuals + metrics. The id-scoped selectors outrank the
   page-local .nb / .nav-area .nb skins that previously made every page drift. */
.common-nav-area{display:flex;align-items:center;gap:var(--nav-btn-gap);flex:1 1 auto;min-width:0}
@media(prefers-reduced-motion:reduce){#commonNavArea *,#commonNavDropdownPortal *,#globalImageRecycle{animation:none!important;transition:none!important}}
#commonNavArea .nb,
#globalImageRecycle,
#commonNavArea .dropdown > .nb {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 4px;
    height: var(--nav-btn-height);
    min-height: var(--nav-btn-height);
    padding: var(--nav-btn-padding);
    border-radius: var(--nav-btn-radius);
    font-family: var(--nav-font);
    font-size: var(--nav-btn-font-size);
    font-weight: var(--nav-btn-font-weight);
    line-height: 1;
    white-space: nowrap;
    border: 1px solid var(--nav-shell-line) !important;
    background: var(--nav-surface) !important;
    color: var(--nav-text) !important;
    cursor: pointer;
    box-shadow: none;
    transition: background .18s ease, border-color .18s ease, color .18s ease, transform .18s ease, box-shadow .18s ease;
}
#commonNavArea .nb:not(.a):hover,
#globalImageRecycle:hover,
#commonNavArea .dropdown > .nb:not(.a):hover {
    border-color: #94a3b8 !important;
    background: var(--nav-surface-hover) !important;
    color: var(--nav-text-strong) !important;
    transform: translateY(-1px);
    box-shadow: 0 4px 12px rgba(15, 23, 42, .07);
}
#globalImageRecycle{margin-left:auto;flex-shrink:0;white-space:nowrap}
@media(max-width:780px){.common-nav-shell:has(>#globalImageRecycle){display:grid!important;grid-template-columns:minmax(0,1fr) auto!important;gap:8px!important}.common-nav-shell:has(>#globalImageRecycle) #commonNavArea{grid-column:1!important;grid-row:1!important;min-width:0;width:auto!important;max-width:100%;overflow-x:auto}.common-nav-shell:has(>#globalImageRecycle) .hd-right{grid-column:1/-1!important;grid-row:2!important}#globalImageRecycle{grid-column:2;grid-row:1;justify-self:end;font-size:12px;padding:7px 10px}}
#commonNavArea .nb.a,
#commonNavArea .dropdown > .nb.a {
    border-color: transparent !important;
    background: var(--nav-active-bg) !important;
    color: var(--nav-active-text) !important;
    box-shadow: none;
}
#commonNavArea #usernameDisplay {
    color: var(--nav-user-accent) !important;
    gap: 6px;
    padding-left: 10px;
    padding-right: 10px;
}
#commonNavArea .nav-user-avatar {
    width: 22px;
    height: 22px;
    border-radius: 50%;
    overflow: hidden;
    flex: 0 0 auto;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    background: var(--nav-surface-hover);
}
#commonNavArea .nav-user-avatar img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    display: block;
}
#commonNavArea .nav-user-name {
    display: inline-flex;
    align-items: center;
    line-height: 1;
}
#commonNavArea .dropdown {
    position: relative;
    display: inline-flex;
    align-items: center;
}
#commonNavArea .dropdown::after {
    content: '';
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    height: 10px;
}
#commonNavArea .dropdown-content,
#commonNavDropdownPortal > .dropdown-content {
    min-width: 110px;
    padding: 4px 0;
    border: 1px solid var(--nav-shell-line);
    border-radius: 10px;
    background: var(--nav-surface);
    box-shadow: var(--nav-menu-shadow);
}
#commonNavArea .dropdown-content {
    display: none;
    position: absolute;
    top: 100%;
    left: 50%;
    z-index: 200;
    margin-top: 8px;
    transform: translateX(-50%);
}
#commonNavArea .dropdown:hover > .dropdown-content,
#commonNavArea .dropdown:focus-within > .dropdown-content,
#commonNavArea .dropdown.is-open > .dropdown-content {
    display: block;
}
#commonNavArea .nb-drop,
#commonNavDropdownPortal .nb-drop {
    display: block;
    width: 100%;
    padding: var(--nav-drop-padding);
    border: 0;
    border-radius: 0;
    background: transparent;
    color: var(--nav-text);
    font-family: var(--nav-font);
    font-size: var(--nav-drop-font-size);
    font-weight: var(--nav-drop-font-weight);
    line-height: 1.2;
    text-align: center;
    white-space: nowrap;
    cursor: pointer;
    transition: background .18s ease, color .18s ease;
}
#commonNavArea .nb-drop:hover,
#commonNavDropdownPortal .nb-drop:hover {
    background: rgba(59, 130, 246, .1);
    color: var(--nav-brand-accent);
}
#commonNavArea .global-theme-toggle {
    height: var(--nav-btn-height);
    min-height: var(--nav-btn-height);
    border-radius: var(--nav-btn-radius);
}
@media (max-width: 780px) {
    :root {
        --nav-btn-padding: 0 6px;
    }
    .common-nav-shell {
        gap: 8px;
    }
    #commonNavArea {
        max-width: 100%;
        gap: 8px;
        overflow-x: auto;
        overflow-y: hidden;
        scrollbar-width: none;
        -webkit-overflow-scrolling: touch;
    }
    #commonNavArea::-webkit-scrollbar {
        display: none;
    }
    #commonNavArea > .nb,
    #commonNavArea > .dropdown,
    #commonNavArea > .global-theme-toggle,
    #commonNavArea > .global-screenshot-btn {
        flex-shrink: 0;
    }
    #commonNavArea .nb {
        overflow: hidden;
        text-overflow: ellipsis;
    }
    #commonNavArea .dropdown:hover > .dropdown-content,
    #commonNavArea .dropdown:focus-within > .dropdown-content {
        display: none;
    }
    #commonNavArea .dropdown.is-open > .dropdown-content {
        display: block;
    }
}
body.dark {
    --bg: #0f172a;
    --card: #1e293b;
    --accent: #f59e0b;
    --t1: #f1f5f9;
    --t2: #cbd5e1;
    --t3: #94a3b8;
    --bd: #334155;
    --tg: #1e293b;
    --tc: #94a3b8;
    --ui-bg: #0f172a;
    --ui-surface: #1e293b;
    --ui-surface-soft: #162033;
    --ui-text: #f1f5f9;
    --ui-text-soft: #cbd5e1;
    --ui-text-muted: #94a3b8;
    --ui-line: #334155;
    --ui-line-strong: #475569;
    --ui-accent: #f59e0b;
    --ui-brand: #f59e0b;
    --ui-brand-soft: rgba(245, 158, 11, .14);
    --ui-focus: 0 0 0 4px rgba(245, 158, 11, .18);
    background: var(--bg, #0f172a);
    color: var(--t1, #f1f5f9);
}
body.dark .hd {
    background: rgba(15, 23, 42, .92);
    border-color: #334155;
}
body.dark {
    --nav-shell-bg: rgba(15, 23, 42, .92);
    --nav-shell-line: #334155;
    --nav-surface: #1e293b;
    --nav-surface-hover: #26354a;
    --nav-text: #cbd5e1;
    --nav-text-strong: #f1f5f9;
    --nav-active-bg: linear-gradient(135deg, #f59e0b, #d97706);
    --nav-active-text: #111827;
    --nav-menu-shadow: 0 18px 46px rgba(0, 0, 0, .36);
}
body.dark .common-nav-shell {
    background: var(--nav-shell-bg);
    border-color: var(--nav-shell-line);
}
body.dark .nb:not(.a),
body.dark .dropbtn,
body.dark .ui-btn,
body.dark .btn,
body.dark .tool-btn {
    background: rgba(30, 41, 59, .78);
    border-color: #334155;
    color: var(--t2, #cbd5e1);
}
body.dark .dropdown-content,
body.dark .ui-menu {
    background: rgba(30, 41, 59, .98);
    border-color: #334155;
    box-shadow: 0 18px 46px rgba(0, 0, 0, .36);
}
body.dark .dropdown-content .nb-drop {
    color: var(--t2, #cbd5e1);
}
.dropdown.is-open > .dropdown-content {
    display:block;
}
#commonNavDropdownPortal {
    position:fixed;
    top:122px;
    left:16px;
    right:16px;
    z-index:2147483000;
    display:block;
}
#commonNavDropdownPortal > .dropdown-content {
    display:block!important;
    position:static!important;
    inset:auto!important;
    width:100%!important;
    max-height:calc(100vh - 142px)!important;
    overflow-y:auto!important;
    transform:none!important;
    margin:0!important;
}
#commonNavArea .dropdown-content .nb-drop.a,
#commonNavArea .dropdown-content .nb-drop.active,
#commonNavDropdownPortal .dropdown-content .nb-drop.a,
#commonNavDropdownPortal .dropdown-content .nb-drop.active {
    background: var(--nav-active-bg);
    color: var(--nav-active-text);
    box-shadow: 0 2px 8px rgba(0,0,0,.15);
}
#commonNavArea .dropdown-content .nb-drop.a:hover,
#commonNavArea .dropdown-content .nb-drop.active:hover,
#commonNavDropdownPortal .dropdown-content .nb-drop.a:hover,
#commonNavDropdownPortal .dropdown-content .nb-drop.active:hover {
    background: var(--nav-active-bg);
    color: var(--nav-active-text);
}
body.dark input,
body.dark textarea,
body.dark select {
    background-color: #111827;
    border-color: #334155;
    color: #f1f5f9;
}
#commonNavArea .global-theme-toggle {
    width: 34px;
    min-width: 34px;
    height: 28px;
    padding: 0;
    border-radius: 7px;
    border: 1px solid var(--nav-shell-line);
    background: var(--nav-surface);
    color: var(--nav-text-strong);
    cursor: pointer;
    font-size: .85rem;
    line-height: 1;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    transition: background .18s ease, border-color .18s ease, color .18s ease, transform .18s ease, box-shadow .18s ease;
}
#commonNavArea .global-theme-toggle:hover {
    border-color: var(--or, #f59e0b);
    box-shadow: 0 4px 12px rgba(15, 23, 42, .12);
    transform: translateY(-1px);
}
body.dark #commonNavArea .global-theme-toggle {
    background: var(--nav-surface);
    border-color: var(--nav-shell-line);
    color: #facc15;
}
#commonNavArea .global-screenshot-btn {
    width: 34px;
    min-width: 34px;
    height: 28px;
    padding: 0;
    border-radius: 7px;
    border: 1px solid var(--nav-shell-line);
    background: var(--nav-surface);
    color: var(--nav-text-strong);
    cursor: pointer;
    font-size: .85rem;
    line-height: 1;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    transition: background .18s ease, border-color .18s ease, color .18s ease, transform .18s ease, box-shadow .18s ease;
}
#commonNavArea .global-screenshot-btn:hover {
    border-color: var(--or, #f59e0b);
    box-shadow: 0 4px 12px rgba(15, 23, 42, .12);
    transform: translateY(-1px);
}
body.dark #commonNavArea .global-screenshot-btn {
    background: var(--nav-surface);
    border-color: var(--nav-shell-line);
    color: #f1f5f9;
}
.nav-promo-chip {
    position: relative;
    display: inline-flex;
    align-items: center;
    justify-content: flex-start;
    gap: 10px;
    min-height: 42px;
    max-width: min(560px, 40vw);
    margin-left: 12px;
    margin-right: clamp(12px, 2.4vw, 32px);
    padding: 10px 20px 10px 18px;
    border-radius: 22px 22px 22px 10px;
    border: 1px solid rgba(255,255,255,.96);
    background: linear-gradient(135deg, rgba(255,255,255,.98), rgba(255,247,237,.96));
    color: #7c2d12;
    text-decoration: none;
    font-size: 1.13rem;
    font-weight: 900;
    line-height: 1.25;
    letter-spacing: .02em;
    white-space: nowrap;
    text-shadow: none;
    box-shadow: 0 8px 0 rgba(99, 102, 241, .08), 0 14px 24px rgba(249, 115, 22, .14), inset 0 1px 0 rgba(255,255,255,.88), 0 0 0 3px rgba(255,255,255,.98), 0 0 0 7px rgba(255, 99, 71, .1);
    overflow: hidden;
    animation: nav-promo-glow 2.8s ease-in-out infinite;
    cursor: pointer;
    transition: transform .18s ease, box-shadow .18s ease, filter .18s ease;
}
.nav-promo-chip:hover {
    transform: translateY(-2px);
    filter: saturate(1.05);
    box-shadow: 0 10px 0 rgba(99, 102, 241, .1), 0 18px 30px rgba(249, 115, 22, .18), inset 0 1px 0 rgba(255,255,255,.9), 0 0 0 3px rgba(255,255,255,.98), 0 0 0 8px rgba(255, 99, 71, .12);
}
.nav-promo-chip-badge {
    position: relative;
    z-index: 1;
    display: inline-flex;
    align-items: center;
    gap: 6px;
    flex: 0 0 auto;
    min-height: 26px;
    padding: 0 12px;
    border-radius: 999px;
    background: linear-gradient(135deg, #ff2d55 0%, #ff8a00 100%);
    color: #fff;
    font-size: .72rem;
    font-weight: 900;
    letter-spacing: .08em;
    text-shadow: 0 1px 2px rgba(124, 45, 18, .26);
    box-shadow: 0 6px 14px rgba(255, 106, 0, .22), inset 0 1px 0 rgba(255,255,255,.28);
}
.nav-promo-chip-badge-star {
    font-size: .86rem;
    line-height: 1;
}
.nav-promo-chip-text {
    position: relative;
    z-index: 1;
    min-width: 0;
    white-space: nowrap;
}
.nav-promo-chip-text::after {
    content: '↗';
    display: inline-block;
    margin-left: 8px;
    font-size: .95em;
    font-weight: 900;
    opacity: .72;
    transform: translate(-1px, 1px);
    transition: transform .18s ease, opacity .18s ease;
}
.nav-promo-chip:hover .nav-promo-chip-text::after {
    opacity: 1;
    transform: translate(0, -1px) scale(1.08);
}
.nav-promo-chip::before {
    content: '';
    position: absolute;
    inset: 0;
    border-radius: inherit;
    background: linear-gradient(135deg, rgba(255, 77, 109, .16), rgba(255, 122, 24, .1) 52%, rgba(255, 214, 10, .18));
    opacity: 1;
    pointer-events: none;
}
.nav-promo-chip::after {
    content: '';
    position: absolute;
    inset: -10px;
    z-index: -1;
    border-radius: 30px;
    padding: 10px;
    box-sizing: border-box;
    background: url("data:image/svg+xml,%3Csvg viewBox='0 0 24 24' xmlns='http://www.w3.org/2000/svg'%3E%3Cpath fill='%23fb7185' d='M12 1.8l2.94 5.96 6.58.96-4.76 4.64 1.12 6.56L12 16.86 6.12 19.92l1.12-6.56L2.48 8.72l6.58-.96z'/%3E%3C/svg%3E") 0 0/18px 18px repeat;
    opacity: .78;
    animation: nav-promo-stars 3.4s linear infinite;
    -webkit-mask: linear-gradient(#000 0 0) content-box, linear-gradient(#000 0 0);
    -webkit-mask-composite: xor;
    mask-composite: exclude;
}
body.dark .nav-promo-chip {
    border-color: rgba(255,255,255,.88);
    background: linear-gradient(135deg, rgba(255,255,255,.98), rgba(255,244,230,.94));
    color: #7c2d12;
    box-shadow: 0 8px 0 rgba(15, 23, 42, .2), 0 16px 28px rgba(249, 115, 22, .14), inset 0 1px 0 rgba(255,255,255,.86), 0 0 0 3px rgba(255,255,255,.94), 0 0 0 7px rgba(255,45,85,.12);
}
@keyframes nav-promo-glow {
    0%, 100% {
        box-shadow: 0 8px 0 rgba(99, 102, 241, .08), 0 14px 24px rgba(249, 115, 22, .14), inset 0 1px 0 rgba(255,255,255,.88), 0 0 0 3px rgba(255,255,255,.98), 0 0 0 7px rgba(255, 99, 71, .1), 0 0 0 0 rgba(255, 122, 24, .12);
    }
    50% {
        box-shadow: 0 8px 0 rgba(99, 102, 241, .08), 0 16px 28px rgba(249, 115, 22, .18), inset 0 1px 0 rgba(255,255,255,.9), 0 0 0 3px rgba(255,255,255,.98), 0 0 0 7px rgba(255, 99, 71, .12), 0 0 0 14px rgba(255, 122, 24, .08);
    }
}
@keyframes nav-promo-stars {
    0% { background-position: 0 0; opacity: .86; }
    100% { background-position: 36px -18px; opacity: 1; }
}
@media (max-width: 1100px) {
    .nav-promo-chip {
        max-width: min(100%, 420px);
        font-size: .94rem;
        margin-left: 0;
        margin-top: 6px;
        margin-right: 0;
    }
    .nav-promo-chip-badge {
        font-size: .64rem;
    }
}

.global-nav-status {
    flex: 0 0 auto;
    color: var(--nav-text);
    font: 700 .75rem/1 var(--nav-font);
    white-space: nowrap;
}
.global-nav-status-error {
    color: #dc2626;
}
@media (max-width: 780px) {
    .common-nav-shell {
        padding-left: 12px;
        padding-right: 12px;
    }
}