@font-face {
    font-family: "RuanMengSource";
    src: url("../fonts/RuanMeng-subset-fixed.ttf") format("truetype");
    font-weight: 400;
    font-style: normal;
    font-display: swap;
}

:root {
    color-scheme: light;
    --page: min(1120px, calc(100vw - 48px));
    --topbar-page: min(1280px, calc(100vw - 48px));
    --body-bg: #e2dcda;
    --ink: #3b303d;
    --muted: #766a75;
    --faint: #9f929a;
    --paper: rgba(255, 249, 243, 0.93);
    --paper-solid: #fffaf5;
    --paper-alt: rgba(255, 246, 240, 0.84);
    --header: rgba(255, 250, 245, 0.76);
    --line: rgba(79, 61, 73, 0.18);
    --line-strong: rgba(79, 61, 73, 0.34);
    --accent: #4d78cf;
    --accent-soft: rgba(77, 120, 207, 0.14);
    --accent-2: #539fe5;
    --accent-2-soft: rgba(83, 159, 229, 0.16);
    --accent-3: #659d8b;
    --success: #177756;
    --error: #b53e4b;
    --background-filter: saturate(0.94) brightness(0.94) contrast(0.95);
    --background-overlay:
        linear-gradient(180deg, rgba(59, 44, 57, 0.12), rgba(58, 46, 56, 0.025) 46%, rgba(48, 39, 51, 0.19)),
        linear-gradient(90deg, rgba(43, 33, 45, 0.08), transparent 54%, rgba(48, 36, 47, 0.10));
    --background-glaze: rgba(255, 255, 255, 0.018);
    --header-text-shadow: 0 1px 9px rgba(255, 250, 245, 0.62);
    --header-text-shadow-compact: 0 1px 7px rgba(255, 250, 245, 0.70);
    --snowflake: rgba(116, 98, 128, 0.46);
    --snow-shadow: rgba(255, 255, 255, 0.42);
    --shadow: 0 22px 54px rgba(40, 28, 47, 0.2);
    --sans: "Nunito", "PingFang SC", "Microsoft YaHei", "Segoe UI", system-ui, sans-serif;
    --display: "ZCOOL KuaiLe", "LXGW WenKai TC", "STKaiti", "KaiTi", cursive;
    --home-snow-font: "LXGW WenKai TC", "PingFang SC", "Microsoft YaHei", sans-serif;
    --site-brand-font: "RuanMengSource", cursive;
    --mono: "SFMono-Regular", "Cascadia Code", "Roboto Mono", Consolas, monospace;
}

html.dark {
    color-scheme: dark;
    --body-bg: #25242d;
    --ink: #f8eee8;
    --muted: #c4b9bc;
    --faint: #91848d;
    --paper: rgba(33, 31, 42, 0.93);
    --paper-solid: #282633;
    --paper-alt: rgba(44, 40, 55, 0.9);
    --header: rgba(28, 27, 38, 0.8);
    --line: rgba(255, 246, 240, 0.16);
    --line-strong: rgba(255, 246, 240, 0.31);
    --accent: #93baff;
    --accent-soft: rgba(147, 186, 255, 0.17);
    --accent-2: #77c2ff;
    --accent-2-soft: rgba(119, 194, 255, 0.18);
    --accent-3: #8ac3ad;
    --success: #70d1a6;
    --error: #ff9aa6;
    --background-filter: saturate(0.92) brightness(0.78);
    --background-overlay:
        linear-gradient(180deg, rgba(8, 8, 14, 0.42), transparent 44%, rgba(8, 8, 14, 0.68)),
        linear-gradient(90deg, rgba(10, 9, 15, 0.16), transparent 54%, rgba(10, 9, 15, 0.14));
    --background-glaze: rgba(255, 255, 255, 0.025);
    --header-text-shadow: 0 1px 9px rgba(16, 12, 24, 0.32);
    --header-text-shadow-compact: 0 1px 7px rgba(16, 12, 24, 0.42);
    --snowflake: rgba(255, 255, 255, 0.72);
    --snow-shadow: rgba(255, 255, 255, 0.24);
    --shadow: 0 26px 70px rgba(0, 0, 0, 0.4);
}

* {
    box-sizing: border-box;
}

html {
    min-width: 320px;
    scroll-behavior: smooth;
}

body {
    min-height: 100vh;
    margin: 0;
    overflow-x: hidden;
    background: var(--body-bg);
    color: var(--ink);
    font-family: var(--sans);
    -webkit-font-smoothing: antialiased;
}

body.menu-open {
    overflow: hidden;
}

button,
input,
textarea {
    font: inherit;
}

button,
a {
    -webkit-tap-highlight-color: transparent;
}

button {
    color: inherit;
}

a {
    color: inherit;
}

.skip-link {
    position: fixed;
    top: 10px;
    left: 10px;
    z-index: 200;
    padding: 10px 14px;
    border: 1px solid var(--line-strong);
    background: var(--paper-solid);
    color: var(--ink);
    transform: translateY(-160%);
}

.skip-link:focus {
    transform: translateY(0);
}

.site-background {
    position: fixed;
    inset: 0;
    z-index: -3;
    background-image: url("../images/bg.webp");
    background-position: center;
    background-size: cover;
    filter: var(--background-filter);
    transform: scale(1.02);
}

.site-background::before {
    content: "";
    position: absolute;
    inset: 0;
    background: var(--background-overlay);
}

.site-background::after {
    content: "";
    position: absolute;
    inset: 0;
    background: var(--background-glaze);
    pointer-events: none;
}

.snow-layer {
    position: fixed;
    inset: 0;
    z-index: 3;
    overflow: hidden;
    pointer-events: none;
}

.snowflake {
    position: absolute;
    top: -16px;
    width: var(--size);
    height: var(--size);
    border: 1px solid var(--snowflake);
    border-radius: 50%;
    opacity: var(--opacity);
    filter: drop-shadow(0 0 4px var(--snow-shadow));
    animation: snow-fall var(--duration) linear var(--delay) infinite;
}

@keyframes snow-fall {
    to {
        transform: translate3d(var(--drift), calc(100vh + 36px), 0);
    }
}

/* Kept for the shared markup; the pages below opt into their own editorial surfaces. */
.site-surface {
    border: 1px solid var(--line);
    background: var(--paper);
    box-shadow: var(--shadow);
}

.site-topbar {
    position: fixed;
    top: 0;
    z-index: 60;
    width: 100%;
    margin: 0;
    border-bottom: 1px solid transparent;
    background: transparent;
    box-shadow: none;
    opacity: 0.88;
    transform: translateY(-2px);
    transition: background 460ms cubic-bezier(0.2, 0.75, 0.25, 1),
        border-color 460ms cubic-bezier(0.2, 0.75, 0.25, 1),
        box-shadow 460ms cubic-bezier(0.2, 0.75, 0.25, 1),
        opacity 360ms ease, transform 460ms cubic-bezier(0.2, 0.75, 0.25, 1);
}

.site-topbar.is-revealed,
.site-topbar:hover,
.site-topbar:focus-within,
body.menu-open .site-topbar {
    border-bottom-color: color-mix(in srgb, var(--line) 82%, transparent);
    background: var(--header);
    box-shadow: 0 8px 24px rgba(31, 25, 36, 0.1);
    opacity: 1;
    transform: translateY(0);
    backdrop-filter: blur(8px);
}

.site-topbar__inner {
    width: var(--topbar-page);
    min-height: 70px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: minmax(180px, 1fr) auto minmax(250px, 1fr);
    align-items: center;
}

.site-brand {
    min-width: 0;
    display: inline-flex;
    align-items: baseline;
    gap: 8px;
    width: max-content;
    text-decoration: none;
}

.site-brand::before {
    content: "";
    width: 6px;
    height: 6px;
    flex: 0 0 auto;
    border-radius: 50%;
    background: var(--accent-2);
    transform: translateY(-2px);
}

.site-brand__name {
    font-family: var(--sans);
    font-size: 20px;
    font-weight: 800;
    letter-spacing: -0.03em;
    white-space: nowrap;
}

.site-brand__name span {
    margin-left: 2px;
    color: var(--accent);
    font-family: var(--display);
    font-size: 24px;
    font-weight: 400;
}

.site-nav {
    display: flex;
    align-items: center;
    gap: 26px;
}

.site-nav a {
    position: relative;
    padding: 23px 2px 20px;
    color: var(--muted);
    font-size: 13px;
    font-weight: 750;
    text-decoration: none;
    transition: color 180ms ease;
}

.site-nav a::after {
    content: "";
    position: absolute;
    right: 0;
    bottom: 13px;
    left: 0;
    height: 2px;
    border-radius: 50%;
    background: var(--accent-2);
    transform: scaleX(0) rotate(-1deg);
    transition: transform 180ms ease;
}

.site-nav a:hover,
.site-nav a:focus-visible,
.site-nav a.is-active,
.site-nav a[aria-current="page"] {
    color: var(--ink);
}

.site-nav a:hover::after,
.site-nav a:focus-visible::after,
.site-nav a.is-active::after,
.site-nav a[aria-current="page"]::after {
    transform: scaleX(1) rotate(-1deg);
}

.site-actions {
    display: flex;
    align-items: center;
    justify-content: flex-end;
    gap: 5px;
}

.site-control,
.menu-toggle {
    min-height: 34px;
    display: inline-flex;
    align-items: center;
    gap: 7px;
    padding: 4px 6px;
    border: 0;
    background: transparent;
    cursor: pointer;
    transition: color 180ms ease, background 180ms ease;
}

.site-control:hover,
.menu-toggle:hover {
    background: var(--accent-soft);
    color: var(--ink);
}

.site-control__signal {
    position: relative;
    width: 13px;
    height: 13px;
    flex: 0 0 auto;
    color: var(--accent);
}

.site-control__signal--theme {
    overflow: hidden;
    border: 1px solid currentColor;
    border-radius: 50%;
}

.site-control__signal--theme::after {
    content: "";
    position: absolute;
    inset: -1px -1px -1px 50%;
    background: currentColor;
}

.site-control__signal--snow::before,
.site-control__signal--snow::after {
    content: "";
    position: absolute;
    top: 50%;
    left: 50%;
    width: 13px;
    height: 1px;
    background: currentColor;
    transform: translate(-50%, -50%);
}

.site-control__signal--snow::after {
    transform: translate(-50%, -50%) rotate(90deg);
}

.site-control__label {
    color: var(--muted);
    font-size: 10px;
    font-weight: 700;
}

.site-control strong {
    padding: 0;
    color: var(--muted);
    font-size: 10px;
    font-weight: 750;
}

.site-control strong::before {
    content: "/";
    margin-right: 4px;
    color: var(--accent-2);
}

.menu-toggle {
    display: none;
    color: var(--muted);
    font-size: 11px;
    font-weight: 750;
}

.menu-toggle > span {
    width: 14px;
    display: grid;
    gap: 4px;
}

.menu-toggle i {
    width: 14px;
    height: 1px;
    display: block;
    background: currentColor;
}

.mobile-menu {
    position: fixed;
    inset: 0;
    z-index: 50;
    visibility: hidden;
    pointer-events: none;
}

.mobile-menu.is-open {
    visibility: visible;
    pointer-events: auto;
}

.mobile-menu__scrim {
    position: absolute;
    inset: 0;
    width: 100%;
    border: 0;
    background: rgba(16, 13, 21, 0.5);
    opacity: 0;
    backdrop-filter: blur(3px);
    transition: opacity 180ms ease;
}

.mobile-menu.is-open .mobile-menu__scrim {
    opacity: 1;
}

.mobile-menu__panel {
    position: absolute;
    top: 70px;
    right: 0;
    left: 0;
    padding: 22px max(24px, calc((100% - 1120px) / 2));
    border-bottom: 1px solid var(--line);
    background: var(--paper-solid);
    box-shadow: var(--shadow);
    transform: translateY(-12px);
    opacity: 0;
    transition: transform 180ms ease, opacity 180ms ease;
}

.mobile-menu.is-open .mobile-menu__panel {
    transform: translateY(0);
    opacity: 1;
}

.mobile-menu__panel > p {
    margin: 0 0 12px;
    color: var(--faint);
    font-family: var(--display);
    font-size: 18px;
}

.mobile-menu nav {
    display: grid;
}

.mobile-menu nav a {
    display: flex;
    align-items: center;
    justify-content: space-between;
    min-height: 46px;
    border-top: 1px solid var(--line);
    color: var(--ink);
    font-size: 15px;
    font-weight: 750;
    text-decoration: none;
}

.mobile-menu nav a::after {
    content: "→";
    color: var(--accent);
    font-size: 18px;
}

:focus-visible {
    outline: 2px solid var(--accent);
    outline-offset: 3px;
}

@media (max-width: 900px) {
    :root {
        --page: min(calc(100% - 32px), 1120px);
        --topbar-page: min(calc(100% - 32px), 1280px);
    }

    .site-background {
        background-image: url("../images/bg-pe.webp");
    }

    .site-topbar__inner {
        grid-template-columns: 1fr auto;
    }

    .site-nav {
        display: none;
    }

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

/* Final proximity behavior: one quiet revealed surface, no animated light
 * beam and no permanent reveal caused by a mouse-clicked control retaining focus. */
.site-topbar::after {
    display: none;
}

.site-topbar {
    transition: background 220ms cubic-bezier(0.2, 0.75, 0.25, 1),
        border-color 220ms cubic-bezier(0.2, 0.75, 0.25, 1),
        box-shadow 220ms cubic-bezier(0.2, 0.75, 0.25, 1),
        backdrop-filter 220ms ease;
}

.site-topbar.is-revealed,
body.menu-open .site-topbar {
    border-bottom-color: color-mix(in srgb, var(--line) 68%, transparent);
    background: color-mix(in srgb, var(--header) 84%, transparent);
    box-shadow: 0 8px 22px rgba(20, 16, 28, 0.08);
    backdrop-filter: blur(9px) saturate(1.02);
}

.site-topbar:focus-within:not(.is-revealed):not(:hover) {
    border-bottom-color: transparent;
    background: transparent;
    box-shadow: none;
    backdrop-filter: none;
}

@media (hover: hover) and (pointer: fine) {
    .site-topbar:hover {
        border-bottom-color: color-mix(in srgb, var(--line) 68%, transparent);
        background: color-mix(in srgb, var(--header) 84%, transparent);
        box-shadow: 0 8px 22px rgba(20, 16, 28, 0.08);
        backdrop-filter: blur(9px) saturate(1.02);
    }
}

.site-control:hover,
.menu-toggle:hover,
.site-control:focus-visible,
.menu-toggle:focus-visible {
    background: color-mix(in srgb, var(--accent-soft) 30%, transparent);
    box-shadow: none;
}

.scroll-rail {
    position: fixed;
    right: clamp(16px, 2.4vw, 30px);
    bottom: clamp(16px, 2.4vw, 30px);
    z-index: 55;
    width: 34px;
    overflow: hidden;
    display: grid;
    grid-template-rows: repeat(2, 34px);
    border: 1px solid color-mix(in srgb, var(--line) 86%, transparent);
    border-radius: 2px;
    background: color-mix(in srgb, var(--paper-solid) 72%, transparent);
    box-shadow: 0 10px 22px rgba(20, 16, 28, 0.12);
    backdrop-filter: blur(8px) saturate(1.02);
}

.scroll-rail[hidden] {
    display: none;
}

.scroll-rail__button {
    display: grid;
    place-items: center;
    width: 34px;
    height: 34px;
    padding: 0;
    border: 0;
    background: transparent;
    color: var(--muted);
    cursor: pointer;
    transition: color 180ms ease, background 180ms ease;
}

.scroll-rail__button + .scroll-rail__button {
    border-top: 1px solid color-mix(in srgb, var(--line) 82%, transparent);
}

.scroll-rail__button span {
    font-family: var(--display);
    font-size: 18px;
    line-height: 1;
}

.scroll-rail__button:hover,
.scroll-rail__button:focus-visible {
    background: color-mix(in srgb, var(--accent-soft) 58%, transparent);
    color: var(--ink);
}

.scroll-rail__button:disabled {
    opacity: 0.34;
    cursor: default;
}

.scroll-rail__button:disabled:hover {
    background: transparent;
    color: var(--muted);
}

body.menu-open .scroll-rail {
    opacity: 0;
    pointer-events: none;
}

@media (max-width: 620px) {
    .scroll-rail {
        right: 14px;
        bottom: 14px;
    }
}

/* Theme changes fade the visual palette only; dimensions and layout remain
 * untouched so the page does not reflow while switching. */
html.theme-transitioning,
html.theme-transitioning body,
html.theme-transitioning *,
html.theme-transitioning *::before,
html.theme-transitioning *::after {
    transition-property: background-color, color, border-color, outline-color,
        box-shadow, text-shadow, fill, stroke, filter;
    transition-duration: 280ms;
    transition-timing-function: cubic-bezier(0.2, 0.75, 0.25, 1);
}

@media (prefers-reduced-motion: reduce) {
    html.theme-transitioning,
    html.theme-transitioning body,
    html.theme-transitioning *,
    html.theme-transitioning *::before,
    html.theme-transitioning *::after {
        transition-duration: 1ms;
    }
}

@media (max-width: 620px) {
    .site-topbar__inner {
        min-height: 62px;
    }

    .site-brand__name {
        font-size: 18px;
    }

    .site-brand__name span {
        font-size: 22px;
    }

    .site-actions {
        gap: 1px;
    }

    .site-control {
        min-height: 32px;
        gap: 4px;
        padding: 4px;
    }

    .site-control strong {
        display: none;
    }

    .site-control__label {
        display: none;
    }

    .site-control__signal {
        width: 15px;
        height: 15px;
    }

    .menu-toggle {
        min-height: 32px;
        padding: 4px 7px;
    }

    .mobile-menu__panel {
        top: 62px;
        padding: 20px 16px;
    }
}

/* Local redesign: the bar stays transparent until approached, but its
 * revealed state reads as one calm site header instead of a row of widgets. */
.site-topbar {
    isolation: isolate;
    transition: background 380ms cubic-bezier(0.2, 0.75, 0.25, 1),
        box-shadow 380ms cubic-bezier(0.2, 0.75, 0.25, 1),
        backdrop-filter 380ms ease;
}

.site-topbar::after {
    content: "";
    position: absolute;
    right: 50%;
    bottom: 0;
    width: var(--page);
    height: 1px;
    background: linear-gradient(90deg, transparent, var(--accent-2) 18%, var(--line-strong) 52%, transparent);
    opacity: 0;
    pointer-events: none;
    transform: translateX(50%) scaleX(0.84);
    transition: opacity 300ms ease, transform 380ms cubic-bezier(0.2, 0.75, 0.25, 1);
}

.site-topbar.is-revealed,
.site-topbar:focus-within,
body.menu-open .site-topbar {
    border-bottom-color: transparent;
    background: color-mix(in srgb, var(--header) 97%, transparent);
    box-shadow: 0 10px 26px rgba(31, 25, 36, 0.13);
    backdrop-filter: blur(12px) saturate(1.08);
}

.site-topbar.is-revealed::after,
.site-topbar:focus-within::after,
body.menu-open .site-topbar::after {
    opacity: 0.78;
    transform: translateX(50%) scaleX(1);
}

@media (hover: hover) and (pointer: fine) {
    .site-topbar:hover {
        border-bottom-color: transparent;
        background: color-mix(in srgb, var(--header) 97%, transparent);
        box-shadow: 0 10px 26px rgba(31, 25, 36, 0.13);
        backdrop-filter: blur(12px) saturate(1.08);
    }

    .site-topbar:hover::after {
        opacity: 0.78;
        transform: translateX(50%) scaleX(1);
    }
}

.site-topbar__inner {
    grid-template-columns: minmax(164px, 1fr) auto minmax(238px, 1fr);
}

.site-brand__name {
    font-family: var(--site-brand-font);
    font-size: 21px;
    font-weight: 400;
    letter-spacing: 0.01em;
}

.site-brand__name span {
    font-family: "LXGW WenKai TC", "STKaiti", "KaiTi", cursive;
    font-size: 25px;
    font-weight: 700;
}

.site-nav {
    gap: 30px;
}

.site-nav a {
    padding: 22px 1px 19px;
    font-family: "LXGW WenKai TC", "PingFang SC", "Microsoft YaHei", sans-serif;
    font-size: 14px;
    font-weight: 700;
    letter-spacing: 0.08em;
}

.site-nav a::after {
    bottom: 12px;
    height: 1px;
    border-radius: 0;
}

.site-actions {
    gap: 2px;
    justify-self: end;
    padding-left: 14px;
    border-left: 1px solid transparent;
    transition: border-color 280ms ease;
}

.site-topbar.is-revealed .site-actions,
.site-topbar:focus-within .site-actions,
body.menu-open .site-actions {
    border-left-color: var(--line);
}

.site-control,
.menu-toggle {
    min-height: 32px;
    gap: 5px;
    padding: 4px 8px;
    border-radius: 0;
    color: var(--muted);
}

.menu-toggle {
    white-space: nowrap;
}

.site-control:hover,
.menu-toggle:hover,
.site-control:focus-visible,
.menu-toggle:focus-visible {
    background: color-mix(in srgb, var(--accent-soft) 46%, transparent);
    color: var(--ink);
}

.site-control__label,
.site-control strong {
    font-family: "LXGW WenKai TC", "PingFang SC", "Microsoft YaHei", sans-serif;
    font-size: 11px;
    font-weight: 700;
    letter-spacing: 0.03em;
}

.site-control strong::before {
    content: "·";
    margin-right: 4px;
}

.menu-toggle {
    font-family: "LXGW WenKai TC", "PingFang SC", "Microsoft YaHei", sans-serif;
    font-size: 12px;
    font-weight: 700;
    letter-spacing: 0.04em;
}

@media (max-width: 900px) {
    .site-actions {
        padding-left: 10px;
    }
}

@supports not (backdrop-filter: blur(1px)) {
    .site-topbar.is-revealed,
    body.menu-open .site-topbar,
    .mobile-menu__panel {
        background: var(--paper-solid);
    }
}

@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        scroll-behavior: auto !important;
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }

    .snow-layer {
        display: none;
    }
}

/* Interaction layer for the shared top bar. The page remains unobstructed by
 * default; the readable surface fades in only when the pointer approaches the
 * top edge, when the bar is hovered, or when the mobile menu is open. */
.site-topbar {
    opacity: 1;
    transform: none;
    background: transparent;
    border-bottom-color: transparent;
    box-shadow: none;
    backdrop-filter: none;
    transition: background 420ms cubic-bezier(0.2, 0.75, 0.25, 1),
        border-color 420ms cubic-bezier(0.2, 0.75, 0.25, 1),
        box-shadow 420ms cubic-bezier(0.2, 0.75, 0.25, 1),
        color 220ms ease;
}

.site-topbar.is-revealed,
.site-topbar:focus-within,
body.menu-open .site-topbar {
    border-bottom-color: color-mix(in srgb, var(--line) 86%, transparent);
    background: color-mix(in srgb, var(--header) 94%, transparent);
    box-shadow: 0 9px 28px rgba(31, 25, 36, 0.14);
    backdrop-filter: blur(10px) saturate(1.04);
}

@media (hover: hover) and (pointer: fine) {
    .site-topbar:hover {
        border-bottom-color: color-mix(in srgb, var(--line) 86%, transparent);
        background: color-mix(in srgb, var(--header) 94%, transparent);
        box-shadow: 0 9px 28px rgba(31, 25, 36, 0.14);
        backdrop-filter: blur(10px) saturate(1.04);
    }
}

.site-topbar__inner {
    min-height: 70px;
}

.site-brand,
.site-nav a,
.site-control,
.menu-toggle {
    text-shadow: var(--header-text-shadow);
}

.site-control,
.menu-toggle {
    border-radius: 2px;
    background: transparent;
}

.site-control:hover,
.menu-toggle:hover,
.site-control:focus-visible,
.menu-toggle:focus-visible {
    background: color-mix(in srgb, var(--accent-soft) 72%, transparent);
}

@media (hover: none) {
    .site-topbar:hover {
        border-bottom-color: transparent;
        background: transparent;
        box-shadow: none;
        backdrop-filter: none;
    }
}

/* This block intentionally follows the legacy shared-bar rules so the
 * current local header has one authoritative revealed state. */
.site-topbar {
    isolation: isolate;
    transition: background 380ms cubic-bezier(0.2, 0.75, 0.25, 1),
        box-shadow 380ms cubic-bezier(0.2, 0.75, 0.25, 1),
        backdrop-filter 380ms ease;
}

.site-topbar::after {
    content: "";
    position: absolute;
    right: 50%;
    bottom: 0;
    width: var(--page);
    height: 1px;
    background: linear-gradient(90deg, transparent, var(--accent-2) 18%, var(--line-strong) 52%, transparent);
    opacity: 0;
    pointer-events: none;
    transform: translateX(50%) scaleX(0.84);
    transition: opacity 300ms ease, transform 380ms cubic-bezier(0.2, 0.75, 0.25, 1);
}

.site-topbar.is-revealed,
.site-topbar:focus-within,
body.menu-open .site-topbar {
    border-bottom-color: transparent;
    background: color-mix(in srgb, var(--header) 97%, transparent);
    box-shadow: 0 10px 26px rgba(31, 25, 36, 0.13);
    backdrop-filter: blur(12px) saturate(1.08);
}

.site-topbar.is-revealed::after,
.site-topbar:focus-within::after,
body.menu-open .site-topbar::after {
    opacity: 0.78;
    transform: translateX(50%) scaleX(1);
}

@media (hover: hover) and (pointer: fine) {
    .site-topbar:hover {
        border-bottom-color: transparent;
        background: color-mix(in srgb, var(--header) 97%, transparent);
        box-shadow: 0 10px 26px rgba(31, 25, 36, 0.13);
        backdrop-filter: blur(12px) saturate(1.08);
    }

    .site-topbar:hover::after {
        opacity: 0.78;
        transform: translateX(50%) scaleX(1);
    }
}

.site-control,
.menu-toggle {
    min-height: 32px;
    gap: 5px;
    padding: 4px 8px;
    border-radius: 0;
    background: transparent;
    color: var(--muted);
}

.site-control:hover,
.menu-toggle:hover,
.site-control:focus-visible,
.menu-toggle:focus-visible {
    background: color-mix(in srgb, var(--accent-soft) 46%, transparent);
    color: var(--ink);
}

@media (max-width: 620px) {
    .site-topbar__inner {
        min-height: 62px;
    }

    .site-brand,
    .site-nav a,
    .site-control,
    .menu-toggle {
        text-shadow: var(--header-text-shadow-compact);
    }
}

@media (max-width: 900px) {
    .site-topbar__inner {
        grid-template-columns: minmax(0, 1fr) auto;
    }

    .site-actions {
        justify-self: end;
    }
}

/* Final topbar override: the later legacy blocks above cannot reintroduce a
 * color beam, a heavy glow, or focus-pinned mouse state. */
.site-topbar::after {
    display: none;
}

.site-topbar {
    transition: background 220ms cubic-bezier(0.2, 0.75, 0.25, 1),
        border-color 220ms cubic-bezier(0.2, 0.75, 0.25, 1),
        box-shadow 220ms cubic-bezier(0.2, 0.75, 0.25, 1),
        backdrop-filter 220ms ease;
}

.site-topbar.is-revealed,
body.menu-open .site-topbar {
    border-bottom-color: color-mix(in srgb, var(--line) 68%, transparent);
    background: color-mix(in srgb, var(--header) 84%, transparent);
    box-shadow: 0 8px 22px rgba(20, 16, 28, 0.08);
    backdrop-filter: blur(9px) saturate(1.02);
}

.site-topbar:focus-within:not(.is-revealed):not(:hover) {
    border-bottom-color: transparent;
    background: transparent;
    box-shadow: none;
    backdrop-filter: none;
}

@media (hover: hover) and (pointer: fine) {
    .site-topbar:hover {
        border-bottom-color: color-mix(in srgb, var(--line) 68%, transparent);
        background: color-mix(in srgb, var(--header) 84%, transparent);
        box-shadow: 0 8px 22px rgba(20, 16, 28, 0.08);
        backdrop-filter: blur(9px) saturate(1.02);
    }
}

.site-control:hover,
.menu-toggle:hover,
.site-control:focus-visible,
.menu-toggle:focus-visible {
    background: color-mix(in srgb, var(--accent-soft) 30%, transparent);
    box-shadow: none;
}

/* Final header-control layer: two compact text switches with a meaningful
 * color stem, replacing the previous decorative circle and plus glyph. */
.site-actions {
    gap: 0;
}

.site-control {
    position: relative;
    min-height: 30px;
    gap: 7px;
    padding: 0 10px 2px;
    border: 0;
    border-bottom: 1px solid color-mix(in srgb, var(--line) 70%, transparent);
    border-radius: 0;
    background: transparent;
    color: var(--muted);
    transition: color 180ms ease, border-color 180ms ease;
}

.site-control + .site-control {
    margin-left: 9px;
    padding-left: 17px;
}

.site-control + .site-control::before {
    content: "";
    position: absolute;
    top: 7px;
    bottom: 7px;
    left: 0;
    width: 1px;
    background: color-mix(in srgb, var(--line) 86%, transparent);
}

.site-control__signal {
    width: 2px;
    height: 13px;
    border: 0;
    border-radius: 0;
    background: currentColor;
}

.site-control__signal::before,
.site-control__signal::after {
    display: none;
}

.site-control__signal--theme {
    color: var(--accent);
}

.site-control__signal--snow {
    color: var(--accent-2);
}

.site-control__label {
    color: var(--muted);
    font-size: 11px;
    font-weight: 750;
    letter-spacing: 0.04em;
}

.site-control strong {
    padding: 0;
    color: var(--ink);
    font-family: var(--display);
    font-size: 13px;
    font-weight: 400;
    letter-spacing: 0;
}

.site-control strong::before {
    content: "";
    margin: 0;
}

.site-control:hover,
.site-control:focus-visible {
    border-bottom-color: color-mix(in srgb, var(--accent-2) 72%, transparent);
    background: transparent;
    color: var(--ink);
}

.site-control:hover .site-control__label,
.site-control:focus-visible .site-control__label {
    color: var(--ink);
}

@media (max-width: 620px) {
    .site-control {
        gap: 5px;
        padding-right: 6px;
        padding-left: 6px;
    }

    .site-control + .site-control {
        margin-left: 4px;
        padding-left: 12px;
    }

    .site-control__label {
        display: none;
    }

    .site-control strong {
        font-size: 12px;
    }
}

/* Keep the familiar theme control, while snow remains a compact icon-only
 * action with its state still exposed through the button label. */
#themeToggle {
    min-height: 32px;
    gap: 5px;
    padding: 4px 8px;
    border-bottom: 0;
    background: transparent;
}

#themeToggle .site-control__signal {
    position: relative;
    width: 13px;
    height: 13px;
    overflow: hidden;
    border: 1px solid currentColor;
    border-radius: 50%;
    background: transparent;
    color: var(--accent);
}

#themeToggle .site-control__signal::before {
    display: none;
}

#themeToggle .site-control__signal::after {
    content: "";
    position: absolute;
    inset: -1px -1px -1px 50%;
    display: block;
    background: currentColor;
}

#themeToggle .site-control__label {
    display: inline;
    color: var(--muted);
    font-size: 10px;
    font-weight: 700;
    letter-spacing: 0;
}

#themeToggle strong {
    display: inline;
    padding: 0;
    color: var(--muted);
    font-family: var(--sans);
    font-size: 10px;
    font-weight: 750;
    letter-spacing: 0;
}

#themeToggle strong::before {
    content: "·";
    margin-right: 4px;
    color: var(--accent-2);
}

#themeToggle:hover,
#themeToggle:focus-visible {
    border-bottom-color: transparent;
    background: color-mix(in srgb, var(--accent-soft) 30%, transparent);
}

#snowToggle {
    min-width: 32px;
    min-height: 32px;
    justify-content: center;
    margin-left: 7px;
    padding: 0;
    border-bottom: 0;
    background: transparent;
}

#snowToggle::before {
    display: none;
}

#snowToggle .site-control__signal {
    position: relative;
    width: 16px;
    height: 16px;
    display: grid;
    place-items: center;
    border: 0;
    background: transparent;
    color: var(--accent);
}

#snowToggle .site-control__signal::before,
#snowToggle .site-control__signal::after {
    content: none;
    display: none;
}

#snowToggle .site-control__snowflake {
    width: 16px;
    height: 16px;
    display: block;
    overflow: visible;
}

#snowToggle .site-control__label,
#snowToggle strong {
    display: none;
}

#snowToggle:hover,
#snowToggle:focus-visible {
    border-bottom-color: transparent;
    background: color-mix(in srgb, var(--accent-soft) 30%, transparent);
}

/* The header keeps the full theme wording through compact tablet widths.
 * On phone/zoom widths, only the redundant menu word collapses first so the
 * brand and controls never occupy the same horizontal space. */
@media (max-width: 460px) {
    .site-topbar__inner {
        grid-template-columns: minmax(0, 1fr) auto;
    }

    .site-actions {
        flex: 0 0 auto;
        padding-left: 6px;
    }

    #themeToggle {
        padding-right: 6px;
        padding-left: 6px;
    }

    #snowToggle {
        margin-left: 4px;
    }

    .menu-toggle {
        width: 32px;
        min-width: 32px;
        justify-content: center;
        gap: 0;
        padding: 0;
        font-size: 0;
    }
}

/* Browser zoom can reduce the CSS viewport below phone width even when the
 * visible window looks wider.  At that point the theme joins the existing
 * icon-only snow/menu controls before either action can cross into the brand. */
@media (max-width: 420px) {
    #themeToggle {
        width: 32px;
        min-width: 32px;
        justify-content: center;
        gap: 0;
        padding: 0;
    }

    #themeToggle .site-control__label,
    #themeToggle strong {
        display: none;
    }
}

/* 320px is the smallest supported phone width.  This trims only the two
 * internal gaps so the original site name remains fully readable. */
@media (max-width: 340px) {
    .site-actions {
        padding-left: 0;
    }

    #snowToggle {
        margin-left: 2px;
    }
}

footer {
    padding: 36px 0 10px;
    color: rgba(255, 255, 255, 0.84);
    font-family: var(--sans);
    font-size: 11px;
    font-weight: 700;
    text-align: center;
    text-shadow: 0 1px 5px rgba(0, 0, 0, 0.48);
}

footer p {
    margin: 0;
}