:root{--paper:#fff;--field:#fff;--ink:#172744;--body:#3b4b64;--mute:#5e6b80;--rule:#dbe3f1;--brand:#194fc4;--brand-dk:#133f9e;--slab:#f1f5fc;--slab-tx:#3b4b64;--sans:"Segoe UI",Arial,sans-serif;--mono:Consolas,"Liberation Mono",monospace;--radius:12px}
*,*::before,*::after{box-sizing:border-box}
html{color-scheme:light;-webkit-text-size-adjust:100%;scroll-padding-top:24px}
body{margin:0;background:var(--paper);color:var(--body);font:400 17px/1.65 var(--sans);-webkit-font-smoothing:antialiased}
img{max-width:100%;height:auto;display:block}
h1,h2,h3{color:var(--ink);font-weight:700;letter-spacing:-.025em;line-height:1.18;margin:0;text-wrap:balance}
h1{font-size:clamp(32px,4.1vw,54px)}h2{font-size:clamp(25px,2.65vw,34px)}h3{font-size:20px}
p{margin:16px 0 0}a{color:var(--brand);text-underline-offset:.2em;text-decoration-thickness:1px;overflow-wrap:anywhere}a:hover{color:var(--brand-dk);text-decoration-thickness:2px}
a:focus-visible,button:focus-visible,input:focus-visible,textarea:focus-visible,summary:focus-visible{outline:3px solid var(--brand);outline-offset:4px}
button,input,textarea{font:inherit}button{cursor:pointer}code{font:.9em/1.5 var(--mono);color:var(--ink);background:var(--slab);border-radius:4px;padding:.15em .35em}
.wrap{width:min(100% - 64px,1200px);margin-inline:auto}.doc{width:min(100%,820px)}
.skip{position:absolute;left:-10000px;width:auto;height:44px;min-width:44px;overflow:hidden;white-space:nowrap}
a.skip:focus{position:fixed;left:16px;top:10px;width:auto;height:auto;clip:auto;padding:12px 20px;min-height:44px;background:var(--paper);border:2px solid var(--brand);z-index:20}
.hd-bar{background:var(--paper);border-bottom:1px solid var(--rule)}
.hd-in{display:flex;align-items:center;gap:22px;min-height:76px;position:relative}
.brandmark{display:flex;align-items:center;gap:12px;flex:0 0 auto;text-decoration:none;min-height:44px}
.brandmark img{height:23px;width:auto}.brandmark span{color:var(--ink);font-size:13px;font-weight:600;line-height:1.35;border-left:1px solid var(--rule);padding-left:12px;max-width:112px}
.nav{display:flex;gap:1px;margin-left:auto;align-items:center;flex-wrap:nowrap}.nav a{display:flex;align-items:center;min-height:44px;padding:0 10px;font-size:14px;font-weight:500;color:var(--body);text-decoration:none;white-space:nowrap;border-radius:6px;transition:background .15s}
.nav a:hover{background:var(--slab);color:var(--brand)}.nav a[aria-current]{background:#eaf0ff;color:var(--brand);font-weight:650}
.menu-toggle{display:none;min-height:44px;padding:0 14px;background:var(--paper);color:var(--ink);border:1px solid var(--rule);border-radius:6px;font-weight:600;margin-left:auto}
.op{background:#f2f6fd;padding:56px 0 30px;border-bottom:1px solid var(--rule)}
.op h1{max-width:850px}.op .lede{font-size:19px;line-height:1.6;max-width:780px;margin:17px 0 0}.find{margin:25px 0 0;max-width:940px}
.find form{display:flex;align-items:stretch;border:1px solid #9fb2d5;background:var(--field);border-radius:8px;overflow:hidden;min-height:60px}
.find input{flex:1 1 auto;min-width:0;border:0;border-radius:0;background:var(--field);padding:16px 18px;color:var(--ink);font-size:17px;appearance:none}.find input::placeholder{color:var(--mute)}
.find button{flex:0 0 auto;border:0;border-radius:0;background:var(--brand);color:#fff;font-weight:650;padding:0 28px;min-width:116px;min-height:60px;transition:background .15s}.find button:hover{background:var(--brand-dk)}
.find .hint{margin:10px 0 0;font-size:14px;color:var(--mute)}.search-label{display:block;font-size:14px;font-weight:600;color:var(--ink);margin-bottom:8px}
.sub{margin:22px 0 0;display:flex;flex-wrap:wrap;gap:0 25px;font-size:14px}.sub a{display:inline-flex;align-items:center;min-height:44px;color:var(--body);text-decoration:none}.sub a:hover{text-decoration:underline;color:var(--brand)}
main section{padding:56px 0}main section+section{border-top:1px solid var(--rule)}.hd2{margin:0 0 25px}.hd2 h2{max-width:820px}.hd2 p{max-width:820px;margin:15px 0 0}.hd2 p:last-child{margin-bottom:0}.hd2--wide{display:block}
figure{margin:0;max-width:min(100%,var(--figure-native,1100px));overflow:hidden;background:var(--field);border:1px solid var(--rule);border-radius:var(--radius)}figure img{width:100%;height:auto}figcaption{font-size:13px;line-height:1.6;color:var(--mute);padding:13px 17px;border-top:1px solid var(--rule);background:var(--field)}.image-view{display:flex;align-items:center;min-height:44px;cursor:zoom-in}.image-view img{border-radius:0}
.fg-doc{width:min(100%,820px)}.fg-wide{width:min(100%,1100px)}
section[data-l="wide"]>.wrap{max-width:1100px}section[data-l="doc"]>.wrap,section[data-l="field"]>.wrap,section[data-l="quote"]>.wrap,section[data-l="steps"]>.wrap{max-width:820px}
.pair{display:grid;grid-template-columns:minmax(0,1fr) minmax(0,1.15fr);gap:38px;align-items:stretch}.pair--flip{grid-template-columns:minmax(0,1.15fr) minmax(0,1fr)}.pair .tx>*:first-child{margin-top:0}.pair figure{display:flex;flex-direction:column}.pair figcaption{margin-top:auto}
.pair.stacked{display:flex;flex-direction:column;width:min(100%,var(--figure-native,820px));gap:24px;margin-inline:auto}.pair.stacked>.tx,.pair.stacked>figure{width:100%}.pair.stacked>figure{order:2}
#accuracy>.wrap{max-width:620px}#asked>.wrap{max-width:630px}#formula>.wrap{max-width:610px}
.ser{display:grid;gap:20px}.ser--doc{width:min(100%,820px)}.ser figure{width:100%}.duo{display:grid;grid-template-columns:minmax(0,1fr) minmax(0,1fr);gap:28px;width:min(100%,1100px)}.duo figure{display:flex;flex-direction:column}.duo figcaption{margin-top:auto}
.field{background:var(--slab);border-left:3px solid var(--brand);border-radius:0 var(--radius) var(--radius) 0;padding:23px 26px;width:100%}.field .fl{font-weight:650;font-size:16px;color:var(--ink);margin:0}.field .fv{display:none}.field .fc{margin:8px 0 0;font-size:16px;line-height:1.65;color:var(--body)}.field--slab{background:var(--slab)}.field--slab .fl,.field--slab .fc{color:var(--ink)}.field--slab .fc a{color:var(--brand)}
.quote{width:100%;border-left:3px solid var(--brand);padding:24px 27px;margin:0;background:var(--slab);border-radius:0 var(--radius) var(--radius) 0}.quote>p{font-size:20px;line-height:1.55;color:var(--ink);margin:0}.quote .cite{margin:16px 0 0;font-size:14px;line-height:1.6;color:var(--mute)}
#browse{padding-top:42px}.tiles{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:24px 20px}.tiles a{display:flex;flex-direction:column;text-decoration:none;color:var(--body);min-width:0}.tiles img{aspect-ratio:1/1;width:100%;object-fit:cover;object-position:center;background:#f7f8fa;border:1px solid var(--rule);border-radius:10px;transition:border-color .15s}.tiles a:hover img{border-color:var(--brand)}.tiles .tl{font-size:17px;font-weight:650;line-height:1.35;color:var(--ink);padding:13px 0 0}.tiles .tl::after{content:" ↗";font-size:14px;color:var(--brand)}.tiles .tn{font-size:14px;line-height:1.6;color:var(--mute);padding:0;margin:7px 0 0}.tile-kind{font-size:12px;letter-spacing:.03em;color:var(--brand);margin-top:5px}
.steps{list-style:none;margin:0;padding:0;counter-reset:s;position:relative}.steps li{counter-increment:s;position:relative;padding:0 0 26px 64px;margin:0;min-height:72px}.steps li::before{content:counter(s,decimal-leading-zero);position:absolute;left:0;top:0;font:650 16px/42px var(--sans);color:var(--brand);border:1px solid #a8bce4;border-radius:50%;background:var(--paper);width:44px;height:44px;text-align:center;z-index:1}.steps li:not(:last-child)::after{content:"";position:absolute;left:21px;top:44px;width:1px;bottom:0;background:#b6c8e8}.steps li:last-child{padding-bottom:0}.steps h3{font-size:21px;margin:0 0 6px}.steps p{margin:0;max-width:68ch}
.faq{margin:0}.faq dt{font-size:18px;font-weight:650;color:var(--ink);padding:22px 0 0}.faq dd{margin:0;padding:9px 0 23px;border-bottom:1px solid var(--rule);max-width:75ch}.faq dd:last-child{border-bottom:0}
a.ext::after{content:" ↗";font-size:.8em;text-decoration:none}.ft{background:var(--slab);color:var(--body);margin-top:0;padding:48px 0 32px;border-top:1px solid var(--rule)}.ft a{color:var(--brand);text-decoration:none}.ft a:hover{text-decoration:underline}.ft .cols{display:grid;grid-template-columns:1.35fr 1fr 1fr 1fr;gap:32px}.ft .mark img{height:24px;width:auto}.ft h2{font-size:16px;letter-spacing:0;line-height:1.4;color:var(--ink);margin:0 0 12px}.ft ul{list-style:none;margin:0;padding:0;font-size:14px}.ft li{margin:0}.ft li a{display:inline-flex;align-items:center;min-height:44px}.ft .fine{margin:28px 0 0;padding:22px 0 0;border-top:1px solid var(--rule);font-size:13px;line-height:1.7;max-width:950px}.ft .fine p{margin:0 0 10px}.ft .fine p:last-child{margin-bottom:0}
.source-note{margin:20px 0 0;font-size:14px;line-height:1.6;padding:14px 18px;border-left:3px solid var(--brand);background:#f0f4fd;color:var(--body);max-width:940px}
.note-tool{padding:26px;background:var(--slab);border:1px solid var(--rule);border-radius:var(--radius)}.note-tool label{display:block;font-weight:600;font-size:15px;color:var(--ink);margin-top:16px}.note-tool input,.note-tool textarea{display:block;width:100%;margin-top:7px;padding:12px 14px;border:1px solid #a3b4d0;border-radius:6px;background:var(--field);color:var(--ink);font-size:16px;min-height:46px}.note-tool input[type="number"]{max-width:160px}.note-tool textarea{resize:vertical;line-height:1.6}.note-tool .tool-error{color:#a1232b;font-size:14px;min-height:24px;margin-top:8px}.note-tool button{margin-top:16px;padding:12px 22px;min-height:44px;background:var(--brand);color:#fff;border:0;border-radius:6px;font-weight:600}.note-tool button:disabled{background:#65738a;cursor:default}.note-tool output{display:block;min-height:24px;font-size:14px;margin-top:10px}.note-tool .tool-help{font-size:14px;margin-top:9px;color:var(--mute)}
@media(max-width:1199px){.hd-in{flex-wrap:wrap;gap:0;min-height:70px}.menu-toggle{display:block}.nav{width:100%;margin-left:0;flex-wrap:wrap;gap:3px;padding:8px 0 15px}.js .nav{display:none}.js .nav.is-open{display:flex}.nav a{font-size:15px;padding:0 14px}.brandmark{margin-block:13px}.pair,.pair--flip{grid-template-columns:1fr}.pair .tx{max-width:820px}.pair figure{max-width:820px}.tiles{gap:20px 16px}.ft .cols{grid-template-columns:repeat(2,minmax(0,1fr))}}
@media(max-width:767px){.wrap{width:calc(100% - 36px)}.op{padding:35px 0 23px}.op h1{font-size:34px;line-height:1.12}.op .lede{font-size:17px}.find{margin-top:22px}.find form{min-height:54px}.find input{padding:13px 12px;font-size:16px}.find button{min-width:84px;min-height:54px;padding:0 14px}.find .hint{font-size:13px}.sub{gap:0 20px;margin-top:15px}.sub a{font-size:13px}main section{padding:38px 0}.hd2{margin-bottom:20px}.hd2 h2{font-size:27px}.hd2 p{font-size:16px}.tiles{grid-template-columns:repeat(2,minmax(0,1fr));gap:24px 14px}.tiles .tl{font-size:16px}.tiles .tn{font-size:13px}.duo{grid-template-columns:minmax(0,1fr);gap:18px}.field{padding:19px 21px}.quote{padding:21px}.quote>p{font-size:18px}.steps li{padding-left:59px}.steps h3{font-size:19px}.ft .cols{gap:26px 18px}.ft{padding-top:34px}.note-tool{padding:20px}.source-note{font-size:13px}.brandmark img{height:21px}.brandmark span{font-size:12px;padding-left:10px;max-width:105px}}
@media(prefers-color-scheme:dark){:root{--paper:#101b2c;--field:#16243a;--ink:#edf3ff;--body:#c2cee1;--mute:#a1b0c9;--rule:#33445f;--brand:#94b8ff;--brand-dk:#bfd3ff;--slab:#1b2b43;--slab-tx:#c2cee1}html{color-scheme:dark}.op{background:#17263d}.find button,.note-tool button{background:#245ac8;color:#fff}.find button:hover,.note-tool button:hover{background:#194bab}.find form,.note-tool input,.note-tool textarea{border-color:#536e99}.nav a[aria-current],.source-note{background:#213655}.tiles img{background:#f7f8fa;border-color:#526580}.steps li::before{border-color:#58709a}.steps li:not(:last-child)::after{background:#58709a}.note-tool .tool-error{color:#ffb7bc}.note-tool button:disabled{background:#536078}}
@media(prefers-reduced-motion:reduce){*,*::before,*::after{animation:none!important;transition:none!important;scroll-behavior:auto!important}}