:root{--green:#427457;--green-soft:#eaf0df;--ink:#304239;--muted:#5b6960;--line:#e2e8df;--bg:#f7f8f3;--card:#fffefa;--accent:#cba24c;color-scheme:light}
*{box-sizing:border-box}
body{margin:0;background:var(--bg);color:var(--ink);font-family:"Hiragino Sans","Noto Sans JP","Yu Gothic UI",sans-serif;font-size:16px;line-height:1.9;-webkit-text-size-adjust:100%}
a{color:var(--green)}
img{max-width:100%;height:auto}
.site-header{display:flex;align-items:center;justify-content:space-between;gap:12px;padding:12px 16px;background:var(--card);border-bottom:1px solid var(--line)}
.logo{display:flex;align-items:center;gap:8px;font-weight:800;font-size:17px;white-space:nowrap;min-width:0;color:var(--ink);text-decoration:none}
.site-header nav{display:flex;gap:14px;font-size:14px;flex-shrink:0}
.site-header nav a{color:var(--ink);text-decoration:none}
main{max-width:760px;margin:0 auto;padding:16px 16px 48px}
main.wide{max-width:1000px}
.crumbs{font-size:12px;color:var(--muted);margin:4px 0 16px;display:flex;flex-wrap:wrap;gap:4px;align-items:center}
.crumbs i{font-style:normal;color:var(--muted)}
.crumbs a{color:var(--muted)}
h1{font-size:26px;line-height:1.5;margin:8px 0 12px}
h1 span{display:block;font-size:16px;color:var(--muted);font-weight:600;margin-top:4px}
h2{font-size:20px;line-height:1.5;margin:40px 0 12px;padding-left:10px;border-left:5px solid var(--green)}
.lead{font-size:16px;margin:0 0 20px}
.btn{display:inline-flex;align-items:center;justify-content:center;min-height:48px;padding:10px 20px;border-radius:12px;border:1px solid var(--line);background:var(--card);color:var(--ink);font:inherit;font-weight:700;text-decoration:none;cursor:pointer}
.btn.primary{background:var(--green);border-color:var(--green);color:#fff}
.btn:disabled{opacity:.45;cursor:not-allowed}
button:focus-visible,a:focus-visible,input:focus-visible{outline:3px solid var(--accent);outline-offset:3px}
.maker{background:var(--card);border:1px solid var(--line);border-radius:16px;padding:16px 16px 12px;margin:20px 0 8px}
.maker h2{margin-top:0;border:0;padding:0}
fieldset{border:0;margin:0 0 14px;padding:0}
legend{font-weight:700;margin-bottom:6px}
.dan-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:8px}
.dan-grid label{position:relative}
.dan-grid input{position:absolute;opacity:0}
.dan-grid span{display:flex;align-items:center;justify-content:center;min-height:48px;border:2px solid var(--line);border-radius:12px;background:#fff;font-weight:700;cursor:pointer}
.dan-grid input:checked+span{border-color:var(--green);background:var(--green-soft);color:var(--green)}
.dan-grid input:focus-visible+span{outline:3px solid var(--accent);outline-offset:2px}
.quick{display:flex;flex-wrap:wrap;gap:8px;margin-top:8px}
.quick button{font:inherit;font-size:14px;border:1px solid var(--line);background:#fff;border-radius:20px;padding:6px 14px;cursor:pointer;min-height:40px}
.radio{display:flex;align-items:center;gap:8px;min-height:40px}
.radio input{width:20px;height:20px;accent-color:var(--green)}
.maker-actions{display:flex;flex-wrap:wrap;gap:10px}
.note{font-size:13px;color:var(--muted);margin:10px 0 0}
.error{color:#a5533f;font-weight:700;margin:0 0 8px}
.status{font-size:14px;font-weight:700;color:var(--green);margin:8px 0 0;min-height:0}.status:empty{display:none}
.jump{margin:-4px 0 20px}
.maker-grid{display:grid;grid-template-columns:1fr 170px;gap:16px;align-items:start}
.maker .sample{margin:0}
@media(max-width:620px){.maker-grid{grid-template-columns:1fr}.maker .sample{max-width:150px;margin:0 auto}}
.print-hint{display:none}
.sheet{margin:20px 0}
.sheet-page{background:#fff;border:1px solid var(--line);border-radius:12px;padding:16px;margin-bottom:12px}
.sheet-head{display:flex;flex-wrap:wrap;justify-content:space-between;gap:8px;border-bottom:2px solid var(--ink);padding-bottom:6px;margin-bottom:10px;font-size:15px}
.qs{list-style:none;padding:0;margin:0;display:grid;grid-template-columns:repeat(2,1fr);column-gap:24px;counter-reset:q}
.qs li{counter-increment:q;font-size:20px;padding:6px 0;border-bottom:1px dotted #d6ddd2;display:flex;align-items:center;white-space:nowrap}
.qs li::before{content:"(" counter(q) ")";font-size:12px;color:var(--muted);width:40px;flex-shrink:0}
.blank{display:inline-block;width:64px;margin-left:6px}
.answers .qs li{font-size:16px}
.answers .qs li b{margin-left:.3em}
.answers .sheet-head span{font-size:13px;color:var(--muted)}
@media(min-width:561px){.qs.cols3{grid-template-columns:repeat(3,1fr)}}
.steps li,.article ul li{margin-bottom:6px}
.app-cta{display:flex;gap:16px;align-items:center;background:var(--green-soft);border-radius:16px;padding:16px;margin:40px 0 20px}
.app-cta img{width:96px;flex-shrink:0}
.app-cta p{margin:4px 0 10px;font-size:14px}
.byline{font-size:13px;color:var(--muted);border-top:1px solid var(--line);margin-top:24px;padding-top:12px}
.hero{display:flex;gap:16px;align-items:center;background:var(--green-soft);border-radius:20px;padding:20px 16px;margin:8px 0 24px}
.hero img{width:120px;flex-shrink:0}
.hero h1{margin-top:0}
.hero p{margin:0}
.cards{display:grid;grid-template-columns:repeat(auto-fill,minmax(220px,1fr));gap:12px}
.card{display:block;background:var(--card);border:1px solid var(--line);border-radius:14px;padding:16px;text-decoration:none;color:var(--ink)}
.card b{display:block;font-size:17px}
.card span{font-size:13px;color:var(--muted)}
.more{text-align:right}
.info{border-collapse:collapse;width:100%;background:var(--card)}
.info th,.info td{border:1px solid var(--line);padding:10px;text-align:left;vertical-align:top;font-size:15px}
.info th{width:30%;background:#f1f4ec;white-space:nowrap}
.site-footer{background:var(--card);border-top:1px solid var(--line);padding:20px 16px 28px;font-size:13px;text-align:center}
.site-footer nav{display:flex;flex-wrap:wrap;justify-content:center;gap:8px 18px;margin:8px 0}
.copy{color:var(--muted);margin:0}

/* 記事の部品 */
.meta{font-size:13px;color:var(--muted);margin:0 0 12px}
.toc{background:var(--card);border:1px solid var(--line);border-radius:14px;padding:12px 16px;margin:16px 0}
.toc ol{margin:6px 0 0;padding-left:1.4em;font-size:15px}
.toc li{margin:2px 0}
.summary{background:var(--green-soft);border-radius:16px;padding:4px 16px 8px;margin:28px 0}
.summary h2{border:0;padding:0;margin:16px 0 8px}
.summary ul{padding-left:1.2em;margin:0 0 8px}
.table-wrap{overflow-x:auto;-webkit-overflow-scrolling:touch;margin:12px 0}
.kuku-table{border-collapse:collapse;width:100%;min-width:360px;background:#fff;font-variant-numeric:tabular-nums;text-align:center}
.kuku-table caption{font-size:13px;color:var(--muted);text-align:left;margin-bottom:4px}
.kuku-table th,.kuku-table td{border:1px solid var(--line);padding:6px 2px;font-size:15px}
.kuku-table thead th,.kuku-table tbody th{background:#f1f4ec;font-size:13px;white-space:nowrap}
.kuku-table td.sq{background:#fbf2dc;font-weight:700}
.flow,.menu{padding-left:1.4em}
.flow li,.menu li{margin-bottom:6px}
.dan{border-top:1px solid var(--line);padding-top:4px}
.dan h3{font-size:17px;margin:16px 0 4px}
details{margin:6px 0}
summary{cursor:pointer;color:var(--green);font-weight:700;min-height:40px;display:flex;align-items:center}
.yomi{list-style:none;padding:0;margin:4px 0;display:grid;grid-template-columns:repeat(auto-fill,minmax(220px,1fr));gap:2px 16px;font-size:15px}
.yomi b{display:inline-block;width:88px;font-variant-numeric:tabular-nums}
.btn.small{min-height:40px;padding:6px 14px;font-size:14px}
.check{background:#fbf2dc;border-radius:14px;padding:12px 16px;margin:16px 0}
.check ul{margin:6px 0 0;padding-left:1.2em}
.trivia{display:grid;grid-template-columns:1fr 1fr;gap:12px;margin:16px 0;clear:both}
.tcard{display:flex;gap:14px;align-items:flex-start;background:var(--card);border:1px solid var(--line);border-radius:16px;padding:14px;position:relative;overflow:hidden}
.tcard::before{content:"";position:absolute;inset:0 auto 0 0;width:5px;background:var(--c)}
/* --c＝左の帯の色、--t＝文字の色（背景 --bg に対して 4.5:1 以上） */
.tcard.num{--c:#427457;--t:#427457;--bg:#eaf0df}.tcard.hist{--c:#b07a3b;--t:#8a5a22;--bg:#f6ecdc}.tcard.yomi{--c:#8a6bb0;--t:#6b4c93;--bg:#efe9f6}.tcard.world{--c:#3f7fa3;--t:#2b6587;--bg:#e4eff5}
.tbig{flex-shrink:0;min-width:76px;height:76px;padding:0 8px;border-radius:14px;background:var(--bg);color:var(--t);display:flex;flex-direction:column;align-items:center;justify-content:center;line-height:1.1;text-align:center}
.tbig b{font-size:26px;font-weight:800;letter-spacing:-.02em}
.tbig small{font-size:12px;font-weight:700}
.ttag{display:inline-block;font-size:11px;font-weight:700;color:var(--t);background:var(--bg);border-radius:20px;padding:1px 10px}
.tcard h3{font-size:16px;line-height:1.5;margin:4px 0 4px}
.tcard p{font-size:14px;line-height:1.8;margin:0}
@media(max-width:700px){.trivia{grid-template-columns:1fr}.tcard{gap:10px;padding:12px}.tbig{min-width:58px;height:58px}.tbig b{font-size:20px}.tbig small{font-size:10px}}
.faq details{background:var(--card);border:1px solid var(--line);border-radius:12px;padding:4px 14px;margin:8px 0}
.faq details p{margin:0 0 10px}
.sources ul{font-size:14px;padding-left:1.2em}
.hero-img{margin:4px 0 16px}.hero-img img{width:100%;height:auto;border-radius:14px;display:block}.hero-img figcaption{font-size:11px;color:var(--muted);margin-top:4px}
.steps-fig{display:flex;flex-wrap:wrap;align-items:center;justify-content:center;gap:6px;margin:12px 0}
.steps-fig span{display:flex;gap:4px;background:var(--green-soft);border-radius:14px;padding:8px}
.steps-fig b{display:grid;place-items:center;width:34px;height:34px;border-radius:50%;background:var(--green);color:#fff;font-size:17px}
.steps-fig i{font-style:normal;color:var(--muted);font-weight:700}
.half-fig{margin:12px 0}
.kuku-table.half td.new{background:#d9e8cf;font-weight:700}
/* 色の違いは背景で見せる。文字はどれも背景に対して 4.5:1 以上 */
.kuku-table.half td.same{color:#4f5c54;background:#e6e8e2}
.kuku-table.half td.one{color:#5b6960;background:#f8f0d8}
.half-fig figcaption{font-size:13px;color:var(--muted);line-height:2}
.k{display:inline-block;width:14px;height:14px;border:1px solid var(--line);vertical-align:-2px;margin:0 4px 0 6px}
.k.new{background:#d9e8cf}.k.same{background:#e6e8e2}.k.one{background:#f8f0d8}
.photo{margin:16px 0}.photo img{width:100%;height:auto;border-radius:14px;display:block}.photo figcaption{font-size:12px;color:var(--muted);margin-top:4px;line-height:1.7}
.sample{margin:16px 0;text-align:center}.sample img{width:100%;max-width:300px;border-radius:8px}.sample figcaption{font-size:13px;color:var(--muted);margin-top:4px}
.mascot{float:right;width:88px;height:88px;margin:-8px 0 4px 12px}
h2+.mascot+p,h2+.mascot+ul{min-height:60px}
@media(max-width:560px){h1{font-size:22px}.hero{flex-direction:column;text-align:center}.app-cta{flex-direction:column;text-align:center}.qs{column-gap:12px}.qs li{font-size:17px}.qs li::before{width:32px}.blank{width:36px}}
/* 時計・たし算ひき算・わり算のプリント（sheet.js） */
.dan-grid.two{grid-template-columns:repeat(2,1fr)}.dan-grid.two span{padding:6px 10px;text-align:center;line-height:1.4;font-size:15px}
.clock{display:block;width:100%;height:auto}
.clock .face{fill:#fff;stroke:#304239;stroke-width:3}
.clock .tk{stroke:#9aa59e;stroke-width:1}.clock .tk5{stroke:#304239;stroke-width:2.2}
.clock .num{font-size:19px;font-weight:700;text-anchor:middle;dominant-baseline:central;fill:#304239}
.clock .fun{font-size:11px;text-anchor:middle;dominant-baseline:central;fill:#2f6fa8}
.clock .hh{stroke:#304239;stroke-width:8;stroke-linecap:round}.clock .mh{stroke:#c0533a;stroke-width:4;stroke-linecap:round}.clock .pin{fill:#304239}
.cq{list-style:none;padding:0;margin:0;display:grid;grid-template-columns:repeat(3,1fr);gap:14px 10px;counter-reset:q}
.cq li{counter-increment:q;position:relative;text-align:center;font-size:16px;line-height:1.6}
.cq li::before{content:"(" counter(q) ")";position:absolute;left:0;top:0;font-size:12px;color:var(--muted)}
.cq .clock{max-width:150px;margin:0 auto 4px}
.cq .ask{display:block;font-size:14px;line-height:1.5}
.cq .ans{display:block;white-space:nowrap}
.cq .pair{display:flex;gap:4px;justify-content:center}.cq .pair figure{margin:0;flex:1;min-width:0}.cq .pair figcaption{font-size:12px;line-height:1.4}
.cq.two{grid-template-columns:repeat(2,1fr)}
.cq li.span2{grid-column:span 2}.cq li.span3{grid-column:1/-1}
.cq .ask.tani{font-size:17px;padding:28px 4px 0}
.cq .ask.big{font-size:18px;font-weight:700;margin:12px 0 2px}
.box{display:inline-block;width:1.9em;height:1.35em;border:2px solid var(--ink);border-radius:4px;vertical-align:middle;margin:0 .25em}
.cq.ans4{grid-template-columns:repeat(4,1fr)}.cq.ans4 .clock{max-width:110px}
.qs.wide li{font-size:18px}
.demo-clocks{display:grid;grid-template-columns:repeat(3,1fr);gap:10px;margin:12px 0}.demo-clocks figure{margin:0;text-align:center;font-size:14px}.demo-clocks .clock{max-width:150px;margin:0 auto}
.fig-box{background:#fff;border:1px solid var(--line);border-radius:12px;padding:12px 14px;margin:12px 0;font-size:15px}
.fig-box .eq{font-size:20px;font-weight:700;letter-spacing:.04em}
@media(max-width:560px){.cq{grid-template-columns:repeat(2,1fr)}.qs.wide li{font-size:15px}}
/* 印刷：作ったプリントだけを出す。余白は @page で取り、1枚＝1つの .sheet-page（各ページに見出し）。こたえは別ページ */
@media print{
 @page{size:A4;margin:12mm 15mm}
 body{background:#fff;font-size:12pt}
 .site-header,.site-footer,.crumbs,.no-print,.article>*:not(#sheet):not(.print-hint){display:none!important}
 main{padding:0;max-width:none}
 .sheet{margin:0}
 .sheet[hidden]{display:none!important}
 .print-hint{display:block;font-size:14pt;line-height:1.8;margin:0}
 #sheet:not([hidden])+.print-hint{display:none!important}
 .sheet-page{border:0;border-radius:0;padding:0;margin:0;break-after:page;break-inside:avoid}
 .sheet-page:last-child{break-after:auto}
 .sheet-head{font-size:12pt;break-after:avoid}
 /* 問題のページ：A4の印刷できる高さ（273mm）に収まる高さで固定し、行を均等に広げる */
 .q-page{height:268mm;display:flex;flex-direction:column}
 .q-page .qs{flex:1;grid-template-rows:repeat(var(--rows),1fr);column-gap:14mm}
 .qs li{font-size:18pt;padding:0;break-inside:avoid}
 .qs.dense li{font-size:15pt}
 .qs li::before{font-size:10pt;width:12mm}
 .blank{width:22mm}
 .answers .qs li{font-size:12pt;line-height:1.4;padding:1.2mm 0}
 .qs.cols3{grid-template-columns:repeat(3,1fr);column-gap:8mm}
 .cq{flex:1;grid-template-columns:repeat(3,1fr);align-content:space-around;gap:4mm 6mm}
 .cq.two{grid-template-columns:repeat(2,1fr)}
 .cq li{font-size:13pt;break-inside:avoid}
 .cq .clock{max-width:46mm}
 .cq .pair .clock{max-width:34mm}
 .cq .ans{line-height:1.5}
 .cq .ask{font-size:12pt}
 .cq .ask.tani{font-size:14pt;padding-top:8mm}
 .qs.wide li{font-size:15pt}
 .cq.ans4{flex:none;grid-template-columns:repeat(4,1fr);gap:2mm 4mm}
 .cq.ans4 .clock{max-width:30mm}
 .cq .ask.big{font-size:15pt}
}