:root {
    color-scheme: light;
    --color-text: #162031;
    --color-tag1: #6c788c;
    --color-tag2: #547157;
    --color-bg: #f3f6fb;
    --color-surface: rgba(255, 255, 255, 0.84);
    --color-surface-strong: #ffffff;
    --color-surface-muted: #edf3fb;
    --color-border: rgba(22, 32, 49, 0.12);
    --color-border-strong: rgba(22, 32, 49, 0.2);
    --color-link: #225b9c;
    --color-link-line: rgba(34, 91, 156, 0.28);
    --color-linkhbg: rgba(89, 143, 211, 0.16);
    --color-linkh: #163a63;
    --color-bq: #628b72;
    --color-notice: #d0455a;
    --color-shadow: 0 20px 50px rgba(15, 23, 42, 0.08);
    --color-shadow-soft: 0 10px 30px rgba(15, 23, 42, 0.06);
    --code-bg: #f6f8fc;
    --code-border: rgba(55, 65, 81, 0.14);
    --page-glow-1: rgba(144, 187, 241, 0.18);
    --page-glow-2: rgba(99, 141, 118, 0.14);
}

@media (prefers-color-scheme: dark) {
    :root {
        color-scheme: dark;
        --color-text: #e7edf7;
        --color-tag1: #9aa7bb;
        --color-tag2: #9abf9c;
        --color-bg: #0b1020;
        --color-surface: rgba(15, 23, 42, 0.78);
        --color-surface-strong: #101827;
        --color-surface-muted: #162238;
        --color-border: rgba(148, 163, 184, 0.18);
        --color-border-strong: rgba(148, 163, 184, 0.26);
        --color-link: #8bc3ff;
        --color-link-line: rgba(139, 195, 255, 0.35);
        --color-linkhbg: rgba(139, 195, 255, 0.16);
        --color-linkh: #d9ecff;
        --color-bq: #8db59a;
        --color-notice: #ff8b8b;
        --color-shadow: 0 24px 60px rgba(0, 0, 0, 0.35);
        --color-shadow-soft: 0 12px 32px rgba(0, 0, 0, 0.3);
        --code-bg: #0f172a;
        --code-border: rgba(148, 163, 184, 0.22);
        --page-glow-1: rgba(71, 119, 183, 0.22);
        --page-glow-2: rgba(74, 118, 90, 0.18);
    }
}

*,
*::before,
*::after {
    box-sizing: border-box;
}

html {
    scrollbar-gutter: stable;
    scroll-behavior: smooth;
    font-size: 14pt;
}

body {
    box-sizing: content-box;
    margin: 0;
    font-family: "Lato", -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", sans-serif;
    font-optical-sizing: auto;
    font-weight: 400;
    font-style: normal;
    font-size: 1rem;
    line-height: 1.5;
    color: var(--color-text);
    background:
        radial-gradient(circle at top, var(--page-glow-1), transparent 38%),
        radial-gradient(circle at right top, var(--page-glow-2), transparent 30%),
        var(--color-bg);
    background-attachment: fixed;
    text-rendering: optimizeLegibility;
    -webkit-font-smoothing: antialiased;
}

body.lang-zh {
    text-align: left;
}

::selection {
    background-color: var(--color-linkhbg);
    color: var(--color-linkh);
}

main,
.text-space {
    min-width: 0;
}

body a {
    color: var(--color-link);
    text-decoration: underline;
    text-decoration-thickness: 0.08em;
    text-underline-offset: 0.18em;
    text-decoration-color: var(--color-link-line);
    transition:
        color 0.18s ease,
        background-color 0.18s ease,
        text-decoration-color 0.18s ease;
    -webkit-box-decoration-break: clone;
    box-decoration-break: clone;
}

body a:visited {
    color: var(--color-link);
}

.text-space a:hover {
    background-color: var(--color-linkhbg);
    color: var(--color-linkh);
    text-decoration-color: transparent;
    border-radius: 0.2rem;
}

body a:focus-visible {
    outline: 2px solid var(--color-link);
    outline-offset: 3px;
    border-radius: 0.25rem;
}

details {
    margin: 1.25rem 0;
    padding: 0.85rem 1rem;
    background-color: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: 1rem;
    box-shadow: var(--color-shadow-soft);
}

details[open] summary {
    margin-bottom: 0.75rem;
}

details > :last-child {
    margin-bottom: 0;
}

summary {
    font-weight: 700;
}

summary:hover {
    cursor: pointer;
    color: var(--color-linkh);
}

/* mathML */
.htmlmathparagraph,
mtext,
math {
    font-family: "Lete Sans Math";
}

.math-container,
#math-container {
    display: block;
    overflow-x: auto;
    overflow-y: hidden;
    padding: 0.5em;
}

.math-container.math-container-tagged {
    display: grid;
    grid-template-columns: minmax(0, 1fr) auto minmax(0, 1fr);
    align-items: center;
    column-gap: 1rem;
    overflow: visible;
    padding: 0.5em 0;
}

.math-container.math-container-tagged .math-tag-spacer {
    min-width: 0;
}

.math-container.math-container-tagged .math-equation {
    min-width: 0;
    overflow-x: auto;
    overflow-y: hidden;
    padding: 0.5em 0;
}

.math-container.math-container-tagged .math-tag {
    justify-self: end;
    white-space: nowrap;
    font-family: "IosevkaC", sans-serif;
}

.math-container.math-container-tagged .math-tag math {
    display: inline;
}

.text-space .langtag {
    color: var(--color-tag1);
}

.sc {
    font-variant-caps: small-caps;
}

p {
    margin: 0 0 1rem;
    hyphens: auto;
}

a.url {
    word-break: break-all;
}

header {
    font-weight: 400;
    font-family: "IosevkaC", sans-serif;
}

.navbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 1rem;
}

.navright {
    display: flex;
    flex-wrap: wrap;
}

.navright a {
    margin: 0 0 0 1em;
}

.navbar a {
    color: var(--color-text);
    text-decoration: none;
}

.navbar a:visited {
    color: var(--color-text);
}

nav {
    margin-bottom: 1.5rem;
    padding-bottom: 0.75rem;
    text-align: right;
    border-bottom: 1px solid var(--color-border-strong);
}

nav a {
    display: inline-flex;
    align-items: center;
    vertical-align: middle;
    font-size: 1.05rem;
    text-decoration: none;
}

.uri {
    overflow-wrap: anywhere;
    word-break: break-word;
    white-space: normal;
}

footer {
    margin-top: 3rem;
    padding-right: 0.2rem;
    color: var(--color-tag1);
    font-size: 0.82rem;
    text-align: right;
}

h1,
h2,
h3,
h4,
h5,
h6 {
    text-align: left;
    text-wrap: balance;
}

.pagetitle {
    margin: 0;
    font-size: 2rem;
    font-weight: 400;
    font-style: normal;
    text-align: left;
    line-height: 1;
    letter-spacing: -0.03em;
}

h1 {
    margin-top: 1.5rem;
    margin-bottom: 0.75rem;
    font-size: 1.44rem;
    font-weight: 700;
    font-style: normal;
    line-height: 1.1;
    letter-spacing: -0.02em;
}

h2 {
    margin-top: 1.75rem;
    margin-bottom: 0.7rem;
    font-size: 1.2rem;
    font-weight: 700;
    font-style: normal;
    line-height: 1.2;
}

h3 {
    margin-top: 1.5rem;
    margin-bottom: 0.6rem;
    font-size: 1rem;
    font-weight: 700;
    font-style: normal;
    line-height: 1.25;
}

h4,
h5,
h6 {
    margin-top: 1.35rem;
    margin-bottom: 0.55rem;
    line-height: 1.3;
}

article .header {
    color: var(--color-tag1);
    font-size: 1rem;
    font-style: normal;
    text-align: left;
    letter-spacing: 0.02em;
}

.info {
    color: var(--color-tag2);
    font-size: 1rem;
    font-style: normal;
    text-align: left;
}

.info a {
    color: var(--color-tag2);
    font-size: 1rem;
    font-style: normal;
    text-align: left;
}

.info a:visited {
    color: var(--color-tag2);
}

section.body {
    margin-top: 1.75rem;
}

section.body > :first-child {
    margin-top: 0;
}

.ascii-art {
    overflow-x: auto;
    font-family: monospace;
    line-height: 1.2;
}

blockquote {
    margin: 1.5rem 0;
    padding: 1rem 1.25rem;
    background-color: var(--color-surface);
    border: 1px solid var(--color-border);
    border-left: 4px solid var(--color-bq);
    border-radius: 0 1rem 1rem 0;
    box-shadow: var(--color-shadow-soft);
}

blockquote p {
    margin: 0;
}

ol,
ul {
    margin: 0 0 1.1rem;
    padding-left: 2em;
}

ul {
    list-style-type: square;
}

li {
    margin-bottom: 0.3em;
    padding-left: 0.15em;
}

li::marker {
    color: var(--color-tag2);
}

table {
    margin: 1.5rem 0;
    border: 1px solid var(--color-border-strong);
    border-collapse: collapse;
    background-color: var(--color-surface-strong);
    box-shadow: var(--color-shadow-soft);
}

th,
td {
    padding: 0.65rem 0.8rem;
    border: 1px solid var(--color-border);
    text-align: left;
    vertical-align: top;
}

th {
    background-color: var(--color-surface-muted);
}

tr:nth-child(even) td {
    background-color: var(--color-surface);
}

figure {
    display: flex;
    flex-flow: column;
    gap: 0.75rem;
    padding: 0.9rem;
    margin: 1.5rem auto;
    max-width: 80%;
    background-color: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: 1.25rem;
    box-shadow: var(--color-shadow-soft);
}

figure img {
    border-radius: 0.9rem;
}

figcaption {
    padding: 0 0.25rem;
    color: var(--color-tag1);
    font-size: 0.92rem;
    text-align: center;
}

.caption {
    display: none;
}

.centerimg img {
    display: block;
    margin: 0 auto;
}

pre,
div.highlight {
    margin: 1.5rem 0;
    padding: 1rem 1.1rem;
    overflow: auto;
    background-color: var(--code-bg);
    border: 1px solid var(--code-border);
    border-radius: 1rem;
    box-shadow: var(--color-shadow-soft);
}

pre code,
div.highlight pre,
div.highlight pre code {
    display: block;
    margin: 0;
    padding: 0;
    overflow: visible;
    background: transparent;
    border: 0;
    box-shadow: none;
}

code {
    display: inline;
    margin: 0;
    padding: 0.12em 0.35em;
    background-color: var(--code-bg);
    border: 1px solid var(--code-border);
    border-radius: 0.45rem;
    font-family: "IosevkaC", monospace;
    font-size: 0.92em;
    font-variant-ligatures: none;
    font-kerning: none;
    text-rendering: optimizeSpeed;
}

.draft-notice {
    display: table;
    margin: 1.5rem auto;
    padding: 0.85rem 1rem;
    color: var(--color-notice);
    text-align: center;
    background-color: var(--color-surface);
    border: 1px solid var(--color-border);
    border-left: 4px solid var(--color-notice);
    border-radius: 1rem;
    box-shadow: var(--color-shadow-soft);
}

.subtitle {
    margin-top: 0.5rem;
    color: var(--color-tag1);
    font-size: 1.2rem;
    line-height: 1.4;
    text-align: left;
}

.subtitle p {
    margin: 0.2rem 0;
}

.gallery {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1rem;
    margin-top: 2em;
}

.gallery img {
    display: block;
    width: 100%;
    max-width: 320px;
    border-radius: 1rem;
    box-shadow: var(--color-shadow-soft);
}

hr {
    margin: 2rem 0;
    border: 0;
    border-top: 1px solid var(--color-border-strong);
}

.toc {
    display: none;
}

/* phones: no sidebar, no sidenotes */
@media (max-width: 768px) {
    body {
        max-width: 876px;
        margin: auto;
        padding: 1rem 5% 3rem;
        text-align: left;
        background-attachment: scroll;
    }

    mjx-container[display="true"] {
        overflow-x: auto;
        overflow-y: hidden;
    }

    figure {
        max-width: 100%;
    }
}

/* sidebar, no sidenotes */
@media (min-width: 769px) {
    body {
        display: flex;
        flex-flow: row wrap;
        width: 95%;
        max-width: 1350px;
        margin: auto;
        padding: 1.5rem 5% 3rem 0;
    }

    .toc {
        display: inline-block;
        width: 33%;
        margin-top: 4.5rem;
        margin-left: 0;
        margin-right: 0;
    }

    div#contents ul,
    div#contents-big ul {
        margin-top: 0.3em;
        margin-bottom: 0.3em;
        margin-left: 0.1rem;
        padding-left: 1.45rem;
        line-height: 1.25;
        list-style-type: decimal;
    }

    div#contents-big ul ul {
        list-style-type: none;
        margin-top: 0.15rem;
        margin-left: 0.2rem;
        padding-left: 0.8rem;
        border-left: 1px solid var(--color-border);
    }

    div#contents-big li + li {
        margin-top: 0.18rem;
    }

    div#contents-big li::marker {
        color: var(--color-tag1);
        font-family: "IosevkaC", sans-serif;
    }

    div#contents-big {
        position: sticky;
        top: 6rem;
        max-height: calc(100vh - 7rem);
        max-height: calc(100dvh - 7rem);
        left: 100%;
        clear: both;
        display: flex;
        flex-direction: column;
        max-width: 68%;
        margin-right: 4em;
        padding: 0.8rem;
        background-color: var(--color-surface);
        background-clip: padding-box;
        border: 1px solid var(--color-border);
        border-radius: 1.25rem;
        box-shadow: var(--color-shadow-soft);
        backdrop-filter: blur(14px);
        font-size: 80%;
        text-align: left;
    }

    div#contents-big .toc-scroll {
        min-height: 0;
        overflow-x: hidden;
        overflow-y: auto;
        overscroll-behavior: contain;
        scrollbar-gutter: stable;
        scrollbar-width: thin;
        scrollbar-color: var(--color-border-strong) transparent;
    }

    div#contents-big .toc-scroll::-webkit-scrollbar {
        width: 0.7rem;
    }

    div#contents-big .toc-scroll::-webkit-scrollbar-track {
        margin-block: 0.45rem;
        background: transparent;
    }

    div#contents-big .toc-scroll::-webkit-scrollbar-thumb {
        background-color: var(--color-border-strong);
        border: 0.18rem solid transparent;
        border-radius: 999px;
        background-clip: content-box;
    }

    div#contents-big .toc-scroll::-webkit-scrollbar-thumb:hover {
        background-color: var(--color-tag1);
    }

    div#contents-big .mini-header {
        margin: 0 0 0.45rem;
        color: var(--color-tag1);
        font-weight: 700;
        font-variant: small-caps;
        letter-spacing: 0.08em;
    }

    div#contents-big a {
        color: var(--color-text);
        text-decoration: none;
    }

    div#contents-big li > a {
        display: block;
        margin: 0 0.2rem;
        padding: 0.14rem 0.32rem;
        border-radius: 0.55rem;
        border: 1px solid transparent;
        transition:
            color 0.18s ease,
            background-color 0.18s ease,
            border-color 0.18s ease,
            transform 0.18s ease;
    }

    div#contents-big a:visited {
        color: var(--color-text);
    }

    div#contents-big a:hover {
        background-color: var(--color-linkhbg);
        color: var(--color-linkh);
    }

    div#contents-big li > a:hover,
    div#contents-big li > a:focus-visible {
        border-color: var(--color-border);
        transform: translateX(2px);
    }

    div#contents-big li > a:focus-visible,
    div#contents-big .mini-header a:focus-visible {
        outline: 2px solid var(--color-link);
        outline-offset: 2px;
    }

    div#contents-big .mini-header a {
        display: inline;
        margin-left: 0.25rem;
        color: var(--color-link);
        font-size: 0.85rem;
        line-height: 1;
        vertical-align: baseline;
        transition: color 0.18s ease;
    }

    div#contents-big .mini-header a:hover {
        background-color: transparent;
        color: var(--color-linkh);
        transform: none;
    }

    .text-space {
        display: inline-block;
        width: 66%;
        max-width: 875px;
    }
}

/* sidebar + sidenotes */
@media (min-width: 1200px) {
    body {
        width: 75%;
        padding-right: 25%;
    }
}

@media print {
    .no-print,
    .no-print * {
        display: none !important;
    }

    body {
        margin: auto;
        background: white;
    }

    blockquote,
    details,
    div#contents-big,
    figure,
    pre,
    div.highlight,
    table {
        box-shadow: none;
    }
}
