@font-face {
    font-family: "Zen Antique";
    font-style: normal;
    font-weight: 400;
    font-display: swap;
    src: url("/assets/fonts/zen-antique/ZenAntique-Regular.woff2") format("woff2");
}

:root {
    color-scheme: dark;
    --canvas: #000000;
    --surface: #090909;
    --surface-raised: #111111;
    --ink: #dededb;
    --ink-strong: #f5f5f1;
    --muted: #aaa9a5;
    --quiet: #7d7d79;
    --line: #4a4a47;
    --line-soft: #262624;
    --focus: #ffffff;
    --accent: #c5c5c0;
    --link: #f5f5f1;
    --action-bg: #ffffff;
    --action-ink: #000000;
    --start-bg: transparent;
    --start-ink: #e6e6e2;
    --start-muted: #898985;
    --start-line: #363634;
    --selection-bg: #ffffff;
    --selection-ink: #000000;
    --visited-bg: transparent;
    --visited-ink: #969692;
    --page-width: 1060px;
    --reading-width: 42rem;
    --radius: .2rem;
    --font-reading: "UD Digi Kyokasho N-R", "UD Digi Kyokasho NK-R", "YuKyokasho", "Noto Sans JP", "Noto Sans CJK JP", sans-serif;
    --font-reading-heading: "Zen Antique", "UD Digi Kyokasho N-R", "UD Digi Kyokasho NK-R", "YuKyokasho", "Noto Sans JP", "Noto Sans CJK JP", sans-serif;
    font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", "Noto Sans JP", "Hiragino Sans", "Yu Gothic UI", sans-serif;
    font-synthesis: none;
}

@media (prefers-color-scheme: light) {
    :root {
        color-scheme: light;
        --canvas: #faf8f2;
        --surface: #f6f4ed;
        --surface-raised: #eef2ef;
        --ink: #253033;
        --ink-strong: #172126;
        --muted: #526164;
        --quiet: #5e7073;
        --line: #91a09f;
        --line-soft: #d2dad6;
        --focus: #225e65;
        --accent: #225e65;
        --link: #225e65;
        --action-bg: #225e65;
        --action-ink: #ffffff;
        --start-bg: transparent;
        --start-ink: #225e65;
        --start-muted: #526164;
        --start-line: #91a09f;
        --selection-bg: #225e65;
        --selection-ink: #ffffff;
        --visited-bg: transparent;
        --visited-ink: #5b6b6c;
    }
}

* {
    box-sizing: border-box;
}

html {
    background: var(--canvas);
    scroll-behavior: smooth;
}

body {
    min-width: 320px;
    margin: 0;
    color: var(--ink);
    background: var(--canvas);
    font-size: 1rem;
    line-height: 1.75;
    text-autospace: normal;
    text-rendering: optimizeLegibility;
}

::selection {
    color: var(--selection-ink);
    background: var(--selection-bg);
}

a {
    color: var(--link);
    text-decoration-color: var(--quiet);
    text-decoration-thickness: 1px;
    text-underline-offset: .2em;
}

a:hover {
    text-decoration-color: currentColor;
}

ruby {
    ruby-position: over;
}

ruby rt,
ruby rp {
    -webkit-user-select: none;
    user-select: none;
}

rt {
    color: var(--quiet);
    font-family: inherit;
    font-size: .5em;
    font-weight: 400;
    letter-spacing: 0;
}

a:focus-visible,
summary:focus-visible {
    outline: 2px solid var(--focus);
    outline-offset: 4px;
    border-radius: var(--radius);
}

[hidden] {
    display: none !important;
}

.skip-link {
    position: fixed;
    z-index: 100;
    top: .75rem;
    left: .75rem;
    padding: .65rem .9rem;
    color: var(--action-ink);
    background: var(--action-bg);
    font-weight: 800;
    transform: translateY(-180%);
}

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

.site-header,
.site-footer {
    border-color: var(--line-soft);
}

.site-header {
    border-bottom: 1px solid var(--line-soft);
}

.site-header-inner,
.site-footer-inner,
.page-shell {
    width: min(calc(100% - 2rem), var(--page-width));
    margin-inline: auto;
}

.site-header-inner {
    display: flex;
    align-items: baseline;
    justify-content: flex-start;
    gap: 0;
    padding-block: 1.1rem;
    white-space: nowrap;
}

.site-name {
    display: inline-flex;
    align-items: baseline;
    color: var(--ink-strong);
    text-decoration: none;
}

.site-title {
    display: inline-block;
    font-family: var(--font-reading-heading);
    font-size: 1.28rem;
    font-weight: 400;
    line-height: 1;
    letter-spacing: .025em;
    text-box-trim: trim-both;
}

.site-concept {
    margin: 0;
    color: var(--quiet);
    font-size: .7rem;
    line-height: 1.2;
    letter-spacing: .06em;
}

.page-shell {
    min-height: calc(100vh - 13rem);
    padding-block: 2.75rem 6rem;
}

.site-footer {
    border-top: 1px solid var(--line-soft);
}

.site-footer-inner {
    display: flex;
    justify-content: flex-end;
    padding-block: 2rem 2.5rem;
    color: var(--quiet);
    font-size: .72rem;
}

.site-footer-link {
    color: inherit;
    text-decoration-color: var(--line);
    text-underline-offset: .25em;
}

.site-footer-link:hover {
    color: var(--ink);
    text-decoration-color: currentColor;
}

.eyebrow,
.section-kicker,
.aside-label,
.node-kind,
.next-heading {
    margin: 0;
    color: var(--accent);
    font-size: .68rem;
    font-weight: 800;
    letter-spacing: .13em;
}

.home-preface,
.topic-index {
    max-width: 52rem;
}

.home-preface {
    max-width: 36rem;
    margin: 0 0 4rem;
    color: var(--ink);
    font-family: var(--font-reading);
    font-size: clamp(1rem, 2.2vw, 1.12rem);
    font-weight: 400;
    line-height: 2;
}

.section-heading {
    display: flex;
    align-items: end;
    justify-content: space-between;
    gap: 1rem;
    margin-bottom: 0;
    padding-bottom: 1rem;
    border-bottom: 1px solid var(--line);
}

.section-heading h1 {
    margin: 0;
    color: var(--quiet);
    font-family: inherit;
    font-size: .82rem;
    font-weight: 500;
    line-height: 1.5;
    letter-spacing: .06em;
}

.section-heading > p {
    margin: 0;
    color: var(--quiet);
    font-size: .7rem;
}

.topic-list {
    display: grid;
}

.topic-card {
    border-bottom: 1px solid var(--line-soft);
}

.topic-card-link {
    display: block;
    padding: 1.6rem .1rem 1.5rem;
    color: inherit;
    text-decoration: none;
}

.topic-featured-label {
    margin: 0 0 .65rem;
    color: var(--accent);
    font-size: .65rem;
    font-weight: 700;
    letter-spacing: .18em;
    line-height: 1.4;
}

.topic-card.is-featured .topic-card-link {
    padding-top: 2rem;
}

.topic-card-link:hover h2 {
    color: var(--link);
    text-decoration: underline;
    text-decoration-thickness: 1px;
    text-underline-offset: .22em;
}

.topic-card-date,
.topic-meta,
.node-time,
.source-meta {
    color: var(--quiet);
    font-size: .7rem;
}

.topic-card h2 {
    margin: 0 0 .65rem;
    color: var(--ink-strong);
    font-family: var(--font-reading-heading);
    font-size: 1.3rem;
    font-weight: 400;
    line-height: 1.55;
}

.topic-card-lead {
    max-width: 44rem;
    margin: 0;
    color: var(--muted);
    font-family: var(--font-reading);
    font-size: .86rem;
    line-height: 1.75;
}

.topic-card-date {
    margin: .85rem 0 0;
}

.tag-list {
    display: flex;
    flex-wrap: wrap;
    gap: .3rem .55rem;
    margin: 1rem 0 0;
    padding: 0;
    color: var(--quiet);
    font-size: .68rem;
    list-style: none;
}

.tag-list li + li::before {
    margin-right: .55rem;
    color: var(--line);
    content: "・";
}

.empty-state {
    margin: 0;
    padding: 1.75rem .1rem;
    border-bottom: 1px solid var(--line-soft);
    color: var(--muted);
}

.topic-layout,
.reading-layout {
    display: grid;
    gap: 3rem;
}

.topic-detail,
.reading-main {
    min-width: 0;
    max-width: var(--reading-width);
}

.topic-detail {
    padding-top: .35rem;
}

.topic-detail h1,
.node-article h1,
.error-page h1 {
    color: var(--ink-strong);
    font-family: var(--font-reading-heading);
    font-weight: 400;
    letter-spacing: -.015em;
}

.topic-detail h1 {
    max-width: 14em;
    margin: .85rem 0 1.6rem;
    font-size: clamp(2.1rem, 9vw, 3.5rem);
    line-height: 1.3;
}

.topic-introduction {
    max-width: 39rem;
    margin-top: 1.65rem;
    font-family: var(--font-reading);
    font-weight: 400;
}

.topic-introduction p {
    margin: 0;
    color: var(--muted);
    font-size: clamp(1rem, 4vw, 1.1rem);
    line-height: 2.05;
}

.topic-introduction p:first-child {
    color: var(--ink);
}

.topic-introduction p + p {
    margin-top: 1.1rem;
}

.topic-detail-meta {
    margin-top: 1.5rem;
}

.start-link {
    display: grid;
    grid-template-columns: minmax(0, 1fr) auto;
    gap: .25rem 1rem;
    align-items: center;
    min-height: 4.8rem;
    margin-top: 2rem;
    padding: .9rem 1rem;
    color: var(--start-ink);
    background: var(--start-bg);
    border: 1px solid var(--start-line);
    border-radius: var(--radius);
    text-decoration: none;
}

.start-link:hover {
    border-color: var(--start-ink);
}

.start-link > span:first-child {
    color: var(--start-muted);
    font-size: .65rem;
    font-weight: 800;
    letter-spacing: .1em;
}

.start-link strong {
    color: var(--start-ink);
    font-family: var(--font-reading-heading);
    font-size: 1rem;
    font-weight: 400;
    line-height: 1.55;
}

.start-link .link-arrow {
    grid-column: 2;
    grid-row: 1 / span 2;
    color: var(--start-ink);
    font-family: system-ui, sans-serif;
    font-size: 1.1rem;
}

.topic-context {
    padding-top: 1rem;
    border-top: 1px solid var(--line-soft);
}

.topic-context .aside-label {
    color: var(--quiet);
}

.topic-context h2 {
    margin: .5rem 0 .7rem;
    color: var(--ink);
    font-family: var(--font-reading-heading);
    font-size: 1rem;
    font-weight: 400;
    line-height: 1.55;
}

.topic-context h2 a {
    display: grid;
    gap: .4rem;
    color: inherit;
    text-decoration: none;
}

.topic-overview-title {
    text-decoration: underline;
    text-decoration-color: var(--quiet);
    text-decoration-thickness: 1px;
    text-underline-offset: .22em;
}

.topic-overview-cue {
    display: inline-flex;
    align-items: center;
    gap: .35rem;
    width: max-content;
    color: var(--quiet);
    font-family: system-ui, sans-serif;
    font-size: .65rem;
    font-weight: 700;
    letter-spacing: .04em;
}

.topic-context > p:not(.aside-label) {
    margin: 0;
    color: var(--quiet);
    font-size: .74rem;
    line-height: 1.75;
}

.topic-glossary {
    margin-top: 1.35rem;
    padding-top: 1rem;
    border-top: 1px solid var(--line-soft);
}

.topic-detail > .topic-glossary {
    margin-top: 2.35rem;
    padding-block: 1.25rem 1.35rem;
    border-bottom: 1px solid var(--line-soft);
}

.topic-glossary .aside-label {
    color: var(--quiet);
}

.topic-glossary-list {
    display: grid;
    gap: .85rem;
    margin: .75rem 0 0;
}

.topic-glossary-item {
    display: grid;
    gap: .1rem;
}

.topic-glossary dt {
    color: var(--ink);
    font-family: var(--font-reading-heading);
    font-size: .8rem;
    font-weight: 400;
    line-height: 1.55;
}

.topic-glossary dd {
    margin: 0;
    color: var(--quiet);
    font-size: .71rem;
    line-height: 1.7;
}

.node-article {
    padding: .45rem 0 2rem;
}

.node-kind {
    display: inline-flex;
    align-items: center;
    gap: .65rem;
}

.node-kind > span {
    width: 1.4rem;
    height: 1px;
    background: currentColor;
}

.node-article h1 {
    max-width: 18em;
    margin: .85rem 0 0;
    font-size: clamp(1.85rem, 7vw, 2.75rem);
    line-height: 1.38;
}

.node-text {
    max-width: 36em;
    margin-block: 2.25rem;
    color: var(--ink-strong);
    font-family: var(--font-reading);
    font-size: clamp(1.16rem, 4.8vw, 1.36rem);
    font-weight: 400;
    line-height: 2.05;
    letter-spacing: .012em;
}

.node-time {
    margin: 0;
}

.notice {
    margin: 0 0 1.5rem;
    padding: .75rem 0;
    border-block: 1px solid var(--line);
    color: var(--ink-strong);
    font-size: .78rem;
}

.evidence {
    margin-top: 2rem;
    padding-block: .25rem;
    border-block: 1px solid var(--line-soft);
}

.evidence summary {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
    min-height: 3rem;
    color: var(--ink);
    cursor: pointer;
    font-size: .78rem;
    font-weight: 800;
    letter-spacing: .06em;
}

.evidence summary small {
    color: var(--quiet);
    font-size: .66rem;
    font-weight: 500;
}

.evidence ol {
    display: grid;
    gap: 1.25rem;
    margin: 1rem 0 .75rem;
    padding-left: 1.2rem;
}

.evidence li {
    padding-left: .25rem;
}

.evidence li::marker {
    color: var(--quiet);
    font-family: ui-monospace, "SFMono-Regular", Consolas, monospace;
    font-size: .66rem;
}

.source-meta {
    display: flex;
    flex-wrap: wrap;
    gap: .35rem .55rem;
    margin: 0 0 .35rem;
}

.source-type {
    color: var(--accent);
    font-weight: 800;
}

.evidence-role {
    color: var(--quiet);
    font-weight: 800;
}

.evidence-context .source-link {
    color: var(--muted);
    font-weight: 600;
}

.source-link {
    display: inline;
    overflow-wrap: anywhere;
    font-size: .86rem;
    font-weight: 700;
}

.evidence li > p:last-child {
    margin: .35rem 0 0;
    color: var(--muted);
    font-size: .76rem;
}

.next-section {
    margin-top: 2.25rem;
}

.next-heading {
    margin-bottom: .85rem;
    color: var(--quiet);
}

.next-grid {
    display: grid;
    gap: .65rem;
}

.deep-link {
    display: grid;
    grid-template-columns: minmax(0, 1fr) auto;
    gap: 1rem;
    align-items: center;
    min-height: 4.8rem;
    padding: .9rem 1rem;
    color: var(--ink-strong);
    background: transparent;
    border: 1px solid var(--start-line);
    border-radius: var(--radius);
    text-decoration: none;
}

.deep-link:hover {
    border-color: var(--start-ink);
}

.deep-link:hover strong {
    text-decoration: underline;
    text-decoration-thickness: 1px;
    text-underline-offset: .2em;
}

.deep-link strong {
    grid-column: 1;
    font-family: var(--font-reading-heading);
    font-size: 1rem;
    font-weight: 400;
    line-height: 1.55;
}

.deep-link-arrow {
    grid-column: 2;
    grid-row: 1;
    color: var(--quiet);
    font-family: system-ui, sans-serif;
    font-size: 1rem;
}

.deep-link.is-visited {
    color: var(--visited-ink);
    background: var(--visited-bg);
    border-color: transparent;
}

.deep-link.is-visited .deep-link-arrow {
    color: var(--visited-ink);
}

.error-page {
    max-width: 42rem;
    padding-block: 2rem;
}

.error-page h1 {
    margin: .75rem 0 1.25rem;
    font-size: clamp(2rem, 8vw, 3.2rem);
    line-height: 1.35;
}

.error-page p:not(.eyebrow) {
    color: var(--muted);
}

@media (min-width: 700px) {
    .home-preface span {
        display: block;
    }

    .site-header-inner,
    .site-footer-inner,
    .page-shell {
        width: min(calc(100% - 4rem), var(--page-width));
    }

    .page-shell {
        padding-block: 4.5rem 8rem;
    }

    .topic-detail .topic-glossary-list {
        grid-template-columns: repeat(2, minmax(0, 1fr));
        gap: 1rem 1.75rem;
    }

}

@media (min-width: 960px) {
    .topic-layout,
    .reading-layout {
        grid-template-columns: minmax(0, var(--reading-width)) minmax(230px, 270px);
        gap: 4rem;
        align-items: start;
    }

    .reading-aside {
        position: sticky;
        top: 2rem;
        padding-left: 1.5rem;
        border-left: 1px solid var(--line-soft);
    }

    .topic-context {
        padding-top: 0;
        border-top: 0;
    }

    .node-text {
        margin-block: 2.6rem;
    }
}

@media (prefers-reduced-motion: reduce) {
    html {
        scroll-behavior: auto;
    }
}