@font-face{font-family:SH0U Serif SC;src:url(/fonts/serif-sc.woff2)format("woff2");font-weight:400 600;font-display:swap}@font-face{font-family:SH0U Hand SC;src:url(/fonts/hand-sc.woff2)format("woff2");font-weight:300 600;font-display:swap}@font-face{font-family:Fraunces;src:url(/fonts/fraunces-latin.woff2)format("woff2");font-weight:300 600;font-display:swap;unicode-range:U+??,U+131,U+152-153,U+2BB-2BC,U+2C6,U+2DA,U+2DC,U+304,U+308,U+329,U+2000-206F,U+20AC,U+2122,U+2191,U+2193,U+2212,U+2215,U+FEFF,U+FFFD}@font-face{font-family:Caveat;src:url(/fonts/caveat-latin.woff2)format("woff2");font-weight:400 700;font-display:swap;unicode-range:U+??,U+131,U+152-153,U+2BB-2BC,U+2C6,U+2DA,U+2DC,U+304,U+308,U+329,U+2000-206F,U+20AC,U+2122,U+2191,U+2193,U+2212,U+2215,U+FEFF,U+FFFD}:root{--paper:#f4f0e8;--paper-2:#ece6d9;--card:#fbf9f5;--ink:#1e1c19;--ink-2:#48433b;--ink-3:#6e675b;--rule:#ddd5c7;--rule-2:#c9bfad;--persimmon:#b9522f;--persimmon-hover:#a2461f;--persimmon-text:#a2461f;--persimmon-soft:#f1ded3;--on-persimmon:#fcf8f2;--olive:#7d8762;--olive-text:#5f6a45;--night:#38414f;--sky-soft:#dce5ea;--sand:#e7d1a6;--wood:#d7bc8e;--shadow-fill:#46341e1a;--lcd:#38414f;--lcd-text:#f3e6c6;--header-bg:#f4f0e8db;--shadow:0 1px 0 #46341e0d, 0 22px 44px -26px #46341e61;--grain-opacity:.06;--display:"Fraunces", "SH0U Serif SC", "Noto Serif SC", "Songti SC", "Source Han Serif SC", "STSong", Georgia, serif;--sans:-apple-system, BlinkMacSystemFont, "PingFang SC", "HarmonyOS Sans SC", "MiSans", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC", "Segoe UI", Roboto, sans-serif;--hand:"Caveat", "SH0U Hand SC", "LXGW WenKai", "Kaiti SC", "STKaiti", "KaiTi", cursive;--hand-zh:"SH0U Hand SC", "LXGW WenKai", "Kaiti SC", "STKaiti", "KaiTi", "Caveat", cursive;--wrap:1200px;--gutter:28px;--header-h:64px;--r:18px;--ease:cubic-bezier(.16, 1, .3, 1);--ease-io:cubic-bezier(.65, 0, .35, 1);--spring:cubic-bezier(.2, 1.5, .4, 1)}@media (prefers-color-scheme:dark){:root:not([data-theme=light]){--paper:#1b1916;--paper-2:#23201c;--card:#2a2622;--ink:#f2ede3;--ink-2:#cfc7b9;--ink-3:#a0988a;--rule:#37332d;--rule-2:#4a453d;--persimmon:#d0714f;--persimmon-hover:#e08565;--persimmon-text:#e08565;--persimmon-soft:#3e2a21;--on-persimmon:#1b1916;--olive:#98a27c;--olive-text:#b4bd98;--night:#2b3340;--sky-soft:#2b3340;--sand:#6a5437;--wood:#4a3a2b;--shadow-fill:#00000059;--lcd:#161a21;--lcd-text:#f3e6c6;--header-bg:#1b1916db;--shadow:0 1px 0 #0003, 0 22px 44px -26px #000000b3;--grain-opacity:.04;--sun-c:#e4dfcf;--lightningcss-light: ;--lightningcss-dark:initial;color-scheme:dark}}:root[data-theme=dark]{--paper:#1b1916;--paper-2:#23201c;--card:#2a2622;--ink:#f2ede3;--ink-2:#cfc7b9;--ink-3:#a0988a;--rule:#37332d;--rule-2:#4a453d;--persimmon:#d0714f;--persimmon-hover:#e08565;--persimmon-text:#e08565;--persimmon-soft:#3e2a21;--on-persimmon:#1b1916;--olive:#98a27c;--olive-text:#b4bd98;--night:#2b3340;--sky-soft:#2b3340;--sand:#6a5437;--wood:#4a3a2b;--shadow-fill:#00000059;--lcd:#161a21;--lcd-text:#f3e6c6;--header-bg:#1b1916db;--shadow:0 1px 0 #0003, 0 22px 44px -26px #000000b3;--grain-opacity:.04;--sun-c:#e4dfcf;--lightningcss-light: ;--lightningcss-dark:initial;color-scheme:dark}@media (max-width:600px){:root{--gutter:16px;--header-h:58px}}*,:before,:after{box-sizing:border-box}html{scroll-behavior:smooth;-webkit-text-size-adjust:100%}html:has(#heroTrack){overflow-anchor:none}body{background:var(--paper);color:var(--ink-2);font:16px/1.8 var(--sans);-webkit-font-smoothing:antialiased;text-rendering:optimizelegibility;margin:0;overflow-x:clip}:lang(en) body,body:lang(en){font-size:17px;line-height:1.65}body:after{content:"";pointer-events:none;z-index:200;opacity:var(--grain-opacity);background-image:url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' width='180' height='180'><filter id='n'><feTurbulence type='fractalNoise' baseFrequency='.8' numOctaves='3' stitchTiles='stitch'/><feColorMatrix values='0 0 0 0 .35 0 0 0 0 .28 0 0 0 0 .2 0 0 0 .6 0'/></filter><rect width='100%' height='100%' filter='url(%23n)'/></svg>");position:fixed;inset:0}img,svg{max-width:100%}a{color:inherit}button{font:inherit;color:inherit}:focus-visible{outline:2px solid var(--persimmon);outline-offset:3px;border-radius:6px}::selection{background:var(--persimmon-soft);color:var(--ink)}[hidden]{display:none!important}h1,h2,h3{font-family:var(--display);color:var(--ink);letter-spacing:-.01em;text-wrap:balance;font-variation-settings:"SOFT" 50;margin:0;font-weight:500}h2{font-size:clamp(1.8rem,3.4vw,3rem);line-height:1.2}h3{font-size:1.2rem;line-height:1.4}p{margin:0}.lede{color:var(--ink-2);max-width:34em;font-size:1.12rem;line-height:1.75}.hand{font-family:var(--hand);font-weight:500}:lang(zh) .hand{font-family:var(--hand-zh);font-weight:400}:lang(en) .hand{font-size:1.22em;line-height:1.3}.fine{color:var(--ink-3);font-size:.82rem;line-height:1.7}.tag{letter-spacing:.04em;color:var(--ink-3);border:1px solid var(--rule-2);white-space:nowrap;border-radius:999px;padding:.12em .7em;font-size:.76rem;display:inline-block}.visually-hidden{clip:rect(0 0 0 0);white-space:nowrap;width:1px;height:1px;position:absolute;overflow:hidden}.skip{z-index:300;background:var(--ink);color:var(--paper);border-radius:8px;padding:8px 14px;text-decoration:none;position:absolute;top:-60px;left:12px}.skip:focus{top:12px}:lang(zh) body{letter-spacing:.02em}:lang(zh) h1,:lang(zh) h2,:lang(zh) h3{letter-spacing:.02em;line-break:strict}:lang(zh) h2{font-size:clamp(1.55rem,2.8vw,2.4rem);line-height:1.42}:lang(zh) h3{line-height:1.5}:lang(zh) p,:lang(zh) li{line-break:strict;text-wrap:pretty}:lang(zh) .lede{font-size:1.06rem;line-height:1.9}.wrap{max-width:var(--wrap);padding-inline:var(--gutter);margin-inline:auto}main>section{scroll-margin-top:var(--header-h);padding-block:clamp(80px,11vw,150px)}.alt{background:var(--paper-2)}.sec-head{gap:14px;margin-bottom:clamp(32px,4.5vw,56px);display:grid}.u{-webkit-box-decoration-break:clone;box-decoration-break:clone;background:url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 100 10' preserveAspectRatio='none'><path d='M2 6.6C18 3.2 40 8.2 62 5.4S90 4.2 98 6.2' fill='none' stroke='%23B9522F' stroke-width='3' stroke-linecap='round' vector-effect='non-scaling-stroke'/></svg>") 0 100%/100% .3em no-repeat;padding-bottom:.12em}.js [data-scroll] .u,.js .u[data-scroll]{background-size:calc(var(--in,1) * 100%) .3em}.accent{color:var(--persimmon)}.ph{display:inline-block}.f-card{fill:var(--card)}.f-paper{fill:var(--paper)}.f-ink{fill:var(--ink)}.f-ink2{fill:var(--ink-2)}.f-ink3{fill:var(--ink-3)}.f-rule{fill:var(--rule)}.f-sand{fill:var(--sand)}.f-wood{fill:var(--wood)}.f-night{fill:var(--night)}.f-persimmon{fill:var(--persimmon)}.f-soft{fill:var(--persimmon-soft)}.f-olive{fill:var(--olive)}.f-sky-soft{fill:var(--sky-soft)}.f-shadow{fill:var(--shadow-fill)}.s-ink{stroke:var(--ink)}.s-ink3{stroke:var(--ink-3)}.s-rule{stroke:var(--rule)}.s-paper{stroke:var(--paper)}.s-persimmon{stroke:var(--persimmon)}.s-olive{stroke:var(--olive)}.svg-q{font:600 13px var(--display)}.btn{font:500 .98rem/1.1 var(--sans);cursor:pointer;transition:background-color .3s var(--ease), transform .2s var(--ease);border:1px solid #0000;border-radius:999px;justify-content:center;align-items:center;gap:.5em;padding:.9em 1.5em;text-decoration:none;display:inline-flex}.btn:active{transform:translateY(1px)scale(.985)}.btn-primary{background:var(--persimmon);color:var(--on-persimmon);box-shadow:0 10px 24px -14px var(--persimmon)}.btn-primary:hover{background:var(--persimmon-hover)}.btn-sm{padding:.62em 1.1em;font-size:.9rem}.link-arrow{color:var(--ink);transition:background-size .5s var(--ease);background:linear-gradient(currentColor,currentColor) 0 100%/100% 1px no-repeat;padding-bottom:2px;font-weight:500;text-decoration:none;display:inline-block}.link-arrow:hover{background-position:100% 100%;background-size:0 1px}.tool{cursor:pointer;border:1px solid var(--rule);background:var(--card);height:36px;color:var(--ink-2);border-radius:999px;align-items:center;gap:4px;padding:0 10px;font-size:.86rem;display:inline-flex}.tool:hover{border-color:var(--rule-2);color:var(--ink)}.ic{fill:none;stroke:currentColor;stroke-width:1.7px;stroke-linecap:round;stroke-linejoin:round;width:18px;height:18px}.ic .ic-fill{fill:currentColor;stroke:none}.seg{border:1px solid var(--rule);background:var(--paper);border-radius:999px;flex-wrap:wrap;gap:4px;padding:4px;display:inline-flex}.seg-btn{cursor:pointer;color:var(--ink-2);transition:background-color .25s var(--ease), color .25s var(--ease);background:0 0;border:0;border-radius:999px;padding:.5em 1em;font-size:.9rem;line-height:1.2}.seg-btn:hover{color:var(--ink)}.seg-btn.is-on{background:var(--persimmon-soft);color:var(--persimmon-text);font-weight:600}.seg-sm .seg-btn{padding:.42em .85em;font-size:.84rem}.input-unit{border-bottom:1.5px solid var(--ink);align-items:baseline;gap:6px;display:inline-flex}.input-unit input{width:4.2em;color:var(--ink);font:600 1.3rem/1.2 var(--display);font-variant-numeric:tabular-nums;background:0 0;border:0;outline:none;padding:2px 0}.input-unit:focus-within{border-bottom-color:var(--persimmon)}.unit-label{color:var(--ink-3);font-size:.9rem}