/* Only formula letters and digits use Helvetica; mathematical symbol fonts
   retain the glyphs and sizing expected by KaTeX. */
@font-face {
    font-family: "SiteMathHelvetica";
    src: local("Helvetica Bold"), local("Helvetica-Bold"),
         local("Arial Bold"), local("Arial-BoldMT");
    font-style: normal;
    font-weight: 700;
    font-display: swap;
    unicode-range: U+0030-0039, U+0041-005A, U+0061-007A;
}

@font-face {
    font-family: "SiteMathHelvetica";
    src: local("Helvetica Bold Oblique"), local("Helvetica-BoldOblique"),
         local("Arial Bold Italic"), local("Arial-BoldItalicMT");
    font-style: italic;
    font-weight: 700;
    font-display: swap;
    unicode-range: U+0030-0039, U+0041-005A, U+0061-007A;
}

/* Important declarations in a layer take precedence over the older,
   unlayered page skins, including their important font declarations. */
@layer site-typography {
    :root, :host {
        --site-font-sans: Helvetica, "Helvetica Neue", Arial, "PingFang SC", "Hiragino Sans GB", "Noto Sans SC", "Microsoft YaHei", sans-serif;
        --ui-font: var(--site-font-sans) !important;
        --palette-font-sans: var(--site-font-sans) !important;
        --palette-font-mono: var(--site-font-sans) !important;
    }

    :where(html, body, body *, :host, :host *):not(:where(.katex, .katex *, mjx-container, mjx-container *, .MathJax, .MathJax *)) {
        font-family: var(--site-font-sans) !important;
    }

    :where(.katex, .katex span) {
        font-weight: 700 !important;
    }

    .katex,
    .katex :is(.textrm, .mainrm, .mathbf, .mathit, .texttt, .mathtt) {
        font-family: "SiteMathHelvetica", KaTeX_Main, "PingFang SC", "Hiragino Sans GB", "Noto Sans SC", "Microsoft YaHei", sans-serif !important;
    }

    .katex :is(.mathnormal, .boldsymbol) {
        font-family: "SiteMathHelvetica", KaTeX_Math, "PingFang SC", "Hiragino Sans GB", "Noto Sans SC", "Microsoft YaHei", sans-serif !important;
    }

    .katex :is(.textsf, .mathsf, .mathboldsf, .textboldsf, .mathitsf, .mathsfit, .textitsf) {
        font-family: "SiteMathHelvetica", KaTeX_SansSerif, "PingFang SC", "Hiragino Sans GB", "Noto Sans SC", "Microsoft YaHei", sans-serif !important;
    }

    .math-block {
        text-align: center !important;
    }

    .katex-display {
        display: block !important;
        min-width: 0 !important;
        max-width: 100% !important;
        overflow-x: auto !important;
        overflow-y: hidden !important;
        text-align: center !important;
    }

    /* Short expressions fill the reading column and center within it. Long
       expressions grow from the left edge so every symbol stays scrollable. */
    .katex-display > .katex {
        display: block !important;
        width: max-content !important;
        min-width: 100% !important;
        max-width: none !important;
        text-align: center !important;
    }

    .katex-display.fleqn > .katex {
        padding-left: 0 !important;
    }

    /* Numbered equations reserve equal space on both sides, keeping the
       expression centered and its number clear of the final symbol. */
    .katex-display > .katex > .katex-html:has(> :is(.tag, .katex-tag)) {
        padding-inline: 3em !important;
    }

    /* Article tag-chip padding must not enlarge equation numbers. */
    .katex .tag {
        padding: 0 !important;
    }
}