:root{--ground:#F2F4EF;--surface:#fff;--ink:#17201C;--muted:#4A5750;--line:#C9D1CB;--line-strong:#8A968F;--action:#0B5D4B;--action-hover:#084536;--tint:#DCEEE7;--plate:#1B2420;--plate-ink:#F2F4EF;--plate-dim:#A9B5AE;--brass:#F0C14B;--warn-bg:#FBEBC8;--warn-ink:#7A4300;--err-bg:#FBE4E0;--err-ink:#9E2A1E;--focus:#B3541E;--tint-line:#9CC9BA;--warn-line:#E3C078;--plate-line:#3a463f;--shadow:rgba(23,32,28,.04);--on-action:#fff;color-scheme:light;
--ui:system-ui,-apple-system,"Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif;--mono:ui-monospace,"SF Mono","Cascadia Mono",Menlo,Consolas,"Liberation Mono",monospace}
@media(prefers-color-scheme:dark){:root:not([data-theme="light"]){--ground:#121815;--surface:#1A221E;--ink:#E8EEEA;--muted:#A9B5AE;--line:#33403A;--line-strong:#7C8A82;--action:#6FD3B4;--action-hover:#9BE5CE;--tint:#1F3A31;--plate:#0B0F0D;--plate-ink:#F2F4EF;--plate-dim:#A9B5AE;--brass:#F0C14B;--warn-bg:#3A2D12;--warn-ink:#F5D48A;--err-bg:#3F1D19;--err-ink:#FFB4A8;--focus:#FFB07A;--tint-line:#2F6652;--warn-line:#7A5E22;--plate-line:#3a463f;--shadow:rgba(0,0,0,.3);--on-action:#08241C;color-scheme:dark;}}
:root[data-theme="dark"]{--ground:#121815;--surface:#1A221E;--ink:#E8EEEA;--muted:#A9B5AE;--line:#33403A;--line-strong:#7C8A82;--action:#6FD3B4;--action-hover:#9BE5CE;--tint:#1F3A31;--plate:#0B0F0D;--plate-ink:#F2F4EF;--plate-dim:#A9B5AE;--brass:#F0C14B;--warn-bg:#3A2D12;--warn-ink:#F5D48A;--err-bg:#3F1D19;--err-ink:#FFB4A8;--focus:#FFB07A;--tint-line:#2F6652;--warn-line:#7A5E22;--plate-line:#3a463f;--shadow:rgba(0,0,0,.3);--on-action:#08241C;color-scheme:dark;}
*,*::before,*::after{box-sizing:border-box}
[hidden]{display:none!important}
html{-webkit-text-size-adjust:100%}
body{margin:0;background:var(--ground);color:var(--ink);font:400 17px/1.6 var(--ui)}
h1,h2,h3{font-weight:700;color:var(--ink)}
h1{font-size:28px;line-height:1.15;letter-spacing:-.01em;margin:8px 0 12px}
h2{font-size:22px;line-height:1.25;margin:48px 0 12px}
h3{font-size:18px;line-height:1.3;margin:28px 0 8px}
img,video,svg,iframe,canvas{max-width:100%;height:auto}
p,ul,ol,table,figure{margin:0 0 16px}
a{color:var(--action);text-underline-offset:2px}
a:hover{color:var(--action-hover)}
:focus-visible{outline:3px solid var(--focus);outline-offset:2px}
.wrap{max-width:1080px;margin:0 auto;padding:0 16px}
.skip{position:absolute;left:8px;top:-60px;background:var(--surface);padding:12px 16px;border-radius:8px;z-index:20}
.skip:focus{top:8px}
.sr-only{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap}
.muted,.crumbs,.meta,.hint,.source,.fine,figcaption{color:var(--muted);font-size:14px;line-height:1.5}

/* header */
.site-header{position:sticky;top:0;z-index:10;background:var(--surface);border-bottom:1px solid var(--line);box-shadow:0 1px 0 var(--shadow)}
.bar{display:flex;align-items:center;justify-content:space-between;min-height:56px;gap:12px}
.brand{display:flex;align-items:center;gap:10px;color:var(--ink);font-weight:700;text-decoration:none;font-size:17px;min-height:48px}
.brand .mark{color:var(--ink);flex:none;width:44px;height:auto}
.nav{display:none}
.nav a,.nav summary{padding:12px;color:var(--ink);text-decoration:none;font-weight:600;font-size:16px;cursor:pointer;display:block;min-height:48px}
.nav a[aria-current],.menu a[aria-current]{text-decoration:underline;text-decoration-thickness:2px}
.dd{position:relative}
.dd ul{position:absolute;right:0;top:100%;background:var(--surface);border:1px solid var(--line);border-radius:8px;list-style:none;margin:0;padding:8px;min-width:260px}
.dd summary{list-style:none}.dd summary::-webkit-details-marker{display:none}
.dd summary::after{content:" \25BE"}
.menu summary{list-style:none;padding:12px 16px;border:1px solid var(--line-strong);border-radius:8px;font-weight:600;min-height:48px;cursor:pointer;background:var(--surface)}
.menu summary::-webkit-details-marker{display:none}
.menu nav{position:absolute;left:0;right:0;top:56px;background:var(--surface);border-bottom:1px solid var(--line);padding:8px 16px 16px}
.menu nav a{display:block;padding:12px 4px;color:var(--ink);font-weight:600;text-decoration:none;border-bottom:1px solid var(--line)}
@media(min-width:720px){.nav{display:flex;gap:4px}.menu{display:none}.wrap{padding:0 24px}}

/* page head and prose */
.page-head{padding-top:16px}
.crumbs{margin:16px 0 0}
.crumbs a{color:var(--muted)}
.lede{font-size:18px;max-width:60ch;margin-bottom:16px}
.prose-wrap{max-width:768px;padding-bottom:32px}
.prose{max-width:68ch}
.prose-wrap .prose h2:first-child{margin-top:24px}
.summary-box{background:var(--tint);border:1px solid var(--tint-line);border-radius:8px;padding:16px;margin:16px 0}
.summary-box p{margin:0}
.toc{background:var(--surface);border:1px solid var(--line);border-radius:8px;padding:16px;margin:0 0 24px;font-size:16px}
.toc ol{margin:8px 0 0;padding-left:20px}
.related ul,.cards{list-style:none;padding:0;display:grid;gap:12px;grid-template-columns:1fr}
.card{display:block;height:100%;background:var(--surface);border:1px solid var(--line);border-radius:8px;padding:16px;color:var(--ink);text-decoration:none}
.card:hover{border-color:var(--action)}
.card strong{display:block;color:var(--action);text-decoration:underline;text-underline-offset:2px;margin-bottom:4px}
.card span{display:block;font-size:15px;color:var(--muted);line-height:1.5}
@media(min-width:720px){.cards{grid-template-columns:repeat(2,1fr)}.related ul{grid-template-columns:repeat(3,1fr)}}
@media(min-width:960px){.cards{grid-template-columns:repeat(3,1fr)}}
.card{transition:border-color .15s,background-color .15s}
.card:hover{background:var(--tint)}
.crumbs a{text-underline-offset:2px}
.lede,.page-head>p{color:var(--ink)}
.page-head h1{max-width:22ch}
@media(min-width:720px){.page-head h1{max-width:none}}

/* buttons and form */
.btn{display:inline-flex;align-items:center;justify-content:center;min-height:48px;padding:0 24px;background:var(--action);color:var(--on-action);border:1px solid var(--action);border-radius:8px;font:600 17px var(--ui);cursor:pointer;text-decoration:none}
.btn:hover{background:var(--action-hover);color:var(--on-action)}
.btn-sample{max-width:100%;min-height:48px;padding:6px 12px;background:var(--surface);color:var(--action);border:1px solid var(--action);border-radius:8px;font:600 16px var(--mono);font-variant-numeric:tabular-nums slashed-zero;cursor:pointer;text-align:left}
.btn-sample small{display:block;font:400 14px var(--ui);color:var(--muted)}
.btn-sample:hover{background:var(--tint)}
.tool-box{background:var(--surface);border:1px solid var(--line);border-radius:8px;padding:16px}
@media(min-width:720px){.tool-box,.answer{padding:24px}.plate-wrap{padding:20px 24px}}
.samples .list>*{flex:0 1 auto}
.field{margin-bottom:16px}
label{display:block;font-weight:600;font-size:14px;line-height:1.3;margin-bottom:4px}
.hint{margin:0 0 8px}
input[type=text],select{width:100%;min-height:48px;padding:8px 12px;border:1px solid var(--line-strong);border-radius:8px;background:var(--surface);color:var(--ink);font:500 17px var(--ui)}
input.serial{font:500 24px/1.2 var(--mono);letter-spacing:.08em;font-variant-numeric:tabular-nums slashed-zero;text-transform:uppercase}
.row{display:flex;flex-direction:column;gap:8px}
.samples{margin-top:16px}
.samples p{margin:0 0 8px;font-size:14px;color:var(--muted)}
.samples .list{display:flex;flex-wrap:wrap;gap:8px}
.error{display:flex;gap:8px;background:var(--err-bg);color:var(--err-ink);border:1px solid var(--err-ink);border-radius:8px;padding:12px 16px;margin:16px 0 0;font-weight:600}
.btn-row .btn{width:100%}
@media(min-width:720px){.btn-row .btn{width:auto}input.serial{font-size:28px}.row{flex-direction:row;align-items:flex-end}.row .field{flex:1}}

/* answer block */
.answer{margin-top:16px;background:var(--surface);border:1px solid var(--line);border-radius:8px;padding:16px}
.plate-wrap{background:var(--plate);border-radius:8px;padding:16px;margin-bottom:16px}
.plate{list-style:none;margin:0;padding:0;display:flex;flex-wrap:wrap;gap:6px}
.plate-empty{color:var(--plate-ink);margin:0;font-size:16px}
.cell{display:flex;flex-direction:column;align-items:center;width:40px}
.cell .ch,.plate.static .ch{display:flex;align-items:center;justify-content:center;width:40px;height:52px;border-radius:4px;border:1px solid var(--plate-line);background:transparent;color:var(--plate-dim);font:600 26px var(--mono);font-variant-numeric:tabular-nums slashed-zero;padding:0;cursor:pointer}
.cell.on .ch{color:var(--brass);border-color:var(--brass)}
.cell .ix{font:400 12px var(--mono);color:var(--plate-dim);margin-top:4px}
.plate.static .ch{cursor:default}
.plate-note{color:var(--plate-ink);font-size:14px;margin:12px 0 0}
.plate-note:empty{display:none}
.legend{font-size:14px;line-height:1.5;color:var(--plate-dim);margin:12px 0 0;max-width:62ch}
.plate-empty+.plate-note+.legend,.plate-wrap>.legend:only-child{margin-top:0}
@media(min-width:720px){.cell,.cell .ch{width:48px}.cell .ch{height:64px;font-size:32px}}
@media(prefers-reduced-motion:no-preference){.plate .cell{animation:in .15s both;animation-delay:calc(var(--i,0)*20ms)}@keyframes in{from{opacity:0}to{opacity:1}}.result{animation:in .15s both}}
.result-label{margin:0;font-size:14px;color:var(--muted)}
.result-year{margin:0;font:700 56px/1 var(--mono);font-variant-numeric:tabular-nums slashed-zero}
.result-year output{display:inline-block;min-height:56px}
@media(min-width:720px){.result-year{font-size:72px}}
.chip{display:inline-flex;align-items:center;gap:6px;height:28px;padding:0 10px;border-radius:8px;font-weight:600;font-size:14px;margin:12px 0}
.chip svg{width:14px;height:14px}
.chip-high{background:var(--tint);color:var(--action);border:1px solid var(--tint-line)}
.chip-approx{background:var(--warn-bg);color:var(--warn-ink);border:1px solid var(--warn-line)}
.chip-guess{background:var(--surface);color:var(--ink);border:1px solid var(--line-strong)}
.facts{display:flex;flex-wrap:wrap;gap:8px 24px;margin:0 0 12px}
.facts div{min-width:96px}
.facts dt{font-size:14px;color:var(--muted)}
.facts dd{margin:0;font:700 24px var(--mono);font-variant-numeric:tabular-nums}
.cands{list-style:none;padding:0;display:grid;gap:8px}
.cands li{border:1px solid var(--line-strong);border-radius:8px;padding:12px 16px;font-size:20px;background:var(--surface)}
.source{margin-top:12px}
details.d{border-top:1px solid var(--line);padding:0}
details.d summary{min-height:48px;display:flex;align-items:center;cursor:pointer;font-weight:600;padding:8px 0;list-style:none}
details.d summary::-webkit-details-marker{display:none}
details.d summary::after{content:"\25B8";margin-left:auto;transition:transform .15s}
details.d[open] summary::after{transform:rotate(90deg)}
details.d>*:not(summary){margin-top:0}
.faq details.d:last-child{border-bottom:1px solid var(--line)}

/* notes, tables */
.note{background:var(--warn-bg);color:var(--warn-ink);border:1px solid var(--warn-line);border-radius:8px;padding:12px 16px;margin:16px 0}
.note p:last-child{margin:0}.note a{color:var(--warn-ink)}
.info{background:var(--tint);border:1px solid var(--tint-line);border-radius:8px;padding:12px 16px;margin:16px 0}
.info p:last-child{margin:0}
.tbl{overflow-x:auto;margin:0 0 16px;border:1px solid var(--line);border-radius:8px;background:var(--surface)}
.tbl:focus-visible{outline-offset:0}
table{border-collapse:collapse;width:100%;font-size:16px}
.tbl table{margin:0;min-width:520px}
th,td{padding:12px;text-align:left;vertical-align:top;border-bottom:1px solid var(--line)}
th{background:var(--tint);font-weight:600}
tbody tr:last-child td,tbody tr:last-child th{border-bottom:0}
tbody th{background:var(--surface);position:sticky;left:0}
code,.mono{font-family:var(--mono);font-variant-numeric:tabular-nums slashed-zero;font-size:.95em}
.fig{margin:0 0 24px}
.plate.static{background:var(--plate);padding:16px;border-radius:8px;margin-bottom:8px}

/* layouts */
.tool-layout{display:grid;gap:0;grid-template-columns:minmax(0,1fr);grid-template-areas:"top" "aside" "rest"}
.tool-top{grid-area:top}.tool-aside{grid-area:aside}.tool-rest{grid-area:rest}
.tool-top,.tool-aside,.tool-rest,.home-lead>*{min-width:0}
.tool-aside h2{margin-top:40px}
.diagram{background:var(--surface);border:1px solid var(--line);border-radius:8px;padding:16px;margin:0 0 16px}
.diagram svg{width:100%;height:auto;max-width:360px;display:block;margin:0 auto 8px}
@media(min-width:960px){.tool-layout{grid-template-columns:minmax(0,720px) 1fr;column-gap:32px;grid-template-areas:"top aside" "rest aside"}
.tool-aside{align-self:start;position:sticky;top:80px}.tool-aside h2{margin-top:0;font-size:22px}}
.home-lead{display:grid;gap:24px}
.slot{margin:24px 0}
.slot:not([hidden]){border:1px solid var(--line);border-radius:8px;padding:16px;text-align:center}

/* footer */
.site-footer{margin-top:48px;background:var(--surface);border-top:1px solid var(--line);padding:32px 0}
.cols{display:grid;gap:16px;margin-bottom:16px}
.site-footer h2{font-size:16px;margin:0 0 8px}
.site-footer ul{list-style:none;margin:0;padding:0}
.site-footer li a{display:inline-block;padding:8px 0;min-height:44px}
@media(min-width:720px){.cols{grid-template-columns:repeat(3,1fr)}}
@media(min-width:960px){h1{font-size:40px;line-height:1.1}h2{font-size:28px;line-height:1.2;margin-top:48px}h3{font-size:20px}body{font-size:18px;line-height:1.65}.site-footer{padding:48px 0 32px}}
.site-footer li a{padding:6px 0;min-height:44px;display:inline-flex;align-items:center}
.site-footer .fine{margin-top:0;margin-bottom:0}.site-footer .fine p{max-width:70ch;margin:0 0 8px}
.tbl th,.tbl td{font-size:16px}.tbl td code{white-space:nowrap}
.tbl:focus-visible{outline-offset:2px}
h2{scroll-margin-top:72px}
.slot[hidden]{margin:0}
.theme-btn{min-width:48px;min-height:48px;padding:0 12px;background:var(--surface);color:var(--ink);border:1px solid var(--line-strong);border-radius:8px;font:600 14px var(--ui);cursor:pointer}
.theme-btn:hover{border-color:var(--action)}
.bar-end{display:flex;align-items:center;gap:8px}

/* design review 1 */
.answer:has(.result[hidden]){background:none;border:0;padding:0}
.answer:has(.result[hidden]) .plate-wrap{background:none;padding:0;margin:0}
.answer:has(.result[hidden]) .plate-empty{color:var(--muted);font-size:14px}
.answer:has(.result:not([hidden])) .empty-hint{display:none}
.empty-hint{margin:0}
.method{margin:16px 0 0}
.page-body>p,.page-body>ol,.page-body>ul:not(.cards),.page-body>h3,.page-body>.info{max-width:68ch}
.prose figure img,.prose-wrap figure img{max-height:520px;width:auto;max-width:100%}
.prose .tbl table:has(th:nth-child(6)){min-width:780px}
.prose .tbl td:nth-child(4),.prose .tbl td:nth-child(5){min-width:15ch}
@media(min-width:960px){.prose-wrap .prose .tbl{position:relative;left:50%;transform:translateX(-50%);width:min(1032px,calc(100vw - 48px))}}
@media(max-width:559px){.tbl.stack{overflow:visible;border:0;background:none}.tbl.stack table{min-width:0}.tbl.stack thead{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0 0 0 0)}
.tbl.stack tr{display:block;border:1px solid var(--line);border-radius:8px;background:var(--surface);margin:0 0 12px;padding:4px 12px}
.tbl.stack th,.tbl.stack td{display:block;border:0;padding:6px 0;position:static;background:none}
.tbl.stack td::before,.tbl.stack th[scope=row]::before{content:attr(data-label);display:block;font-size:14px;font-weight:400;color:var(--muted)}
.tbl.stack th[scope=row]{font-size:17px}}
@media print{:root,:root[data-theme]{--ground:#fff;--surface:#fff;--ink:#000;--muted:#000}.theme-btn,.site-header,.site-footer,.slot{display:none}}

/* design review 2 */
.menu-h{margin:12px 0 0;font-size:14px;font-weight:600;color:var(--muted)}
.theme-btn[aria-pressed="true"]{background:var(--ink);color:var(--surface);border-color:var(--ink)}
.help-link{margin:12px 0 0;font-size:16px}
.scope-note{margin:0 0 12px;padding:8px 12px;background:var(--warn-bg);color:var(--warn-ink);border:1px solid var(--warn-line);border-radius:8px;font-size:16px}
.scope-note p{margin:0}
@media(max-width:559px){.prose .tbl.stack table,.prose .tbl.stack table:has(th:nth-child(6)){min-width:0}.prose .tbl.stack td{min-width:0}.tbl.stack td code{white-space:normal;overflow-wrap:anywhere}}

/* design review 3 */
.btn-sample{font:600 16px var(--ui)}
.btn-sample small{font:400 14px var(--mono);font-variant-numeric:tabular-nums slashed-zero}
.formats-note{margin:8px 0 0}
.scope-note{background:none;color:var(--ink);border:0;border-top:1px solid var(--line);border-bottom:1px solid var(--line);border-radius:0;padding:8px 0;font-size:15px}
th{background:none;border-bottom:1px solid var(--line-strong)}
.info{background:none;border:0;border-top:1px solid var(--line);border-radius:0;padding:12px 0}
.summary-box{background:none;border:0;border-top:1px solid var(--line);border-bottom:1px solid var(--line);border-radius:0;padding:12px 0}
.site-footer{background:none}
@media(max-width:719px){.cols{grid-template-columns:1fr 1fr;gap:8px 16px}.cols>div:first-child{grid-column:1/-1}.site-footer{padding:24px 0}.site-footer li a{min-height:44px;padding:4px 0}}

/* design review 4 */
.page-head .meta{margin:0 0 8px}
.trust-line{margin:0 0 16px;font-size:16px;max-width:60ch}
.card:hover{background:none;border-color:var(--action)}
.cards .card,.cards .card:hover{border-width:1px 0 0;border-radius:0;padding:12px 0;background:none}
.cards .card:hover{border-color:var(--action)}
.cards{gap:0 24px}
.btn-sample{color:var(--ink);border-color:var(--line-strong)}
.btn-sample:hover{background:none;border-color:var(--action)}
.note{background:none;color:var(--ink);border:0;border-top:1px solid var(--line);border-bottom:1px solid var(--line);border-radius:0;padding:12px 0}
.note a{color:var(--action)}
.site-header{background:var(--ground)}
.theme-btn,.theme-btn[aria-pressed="true"]{background:none;color:var(--ink);border-color:var(--line-strong)}
.slot:not([hidden]){margin:32px 0;border:1px dashed var(--line);text-align:center}
.slot:not([hidden])::before{content:"Advertisement";display:block;font-size:14px;color:var(--muted);margin-bottom:8px}
.hint,.samples p{font-size:15px}
label{font-size:16px}
figcaption,.source,.btn-sample small,.facts dt,.result-label{font-size:15px}
.site-footer .fine{color:var(--ink)}
td,th,.facts dd,.cands li{font-variant-numeric:tabular-nums}