:root{--study:#2563eb;--ink:#172033;--muted:#526277;--line:#d9e1ec;--paper:#fff}*{box-sizing:border-box}body{margin:0;background:#f4f7fb;color:var(--ink);font-family:system-ui,-apple-system,"Noto Sans JP",sans-serif;line-height:1.6}.study-header{background:#fff;border-bottom:1px solid var(--line)}.wrap{width:min(960px,calc(100% - 32px));margin:auto}.study-header .wrap{padding:16px 0;display:flex;justify-content:space-between;align-items:center;gap:16px}.brand{font-weight:800;color:var(--study);text-decoration:none;font-size:1.15rem}.study-nav a,.breadcrumbs a{color:#365171}.study-nav a{margin-left:15px}main{padding:26px 0 50px}.breadcrumbs{font-size:.88rem;margin-bottom:18px}.breadcrumbs span{margin:0 5px;color:#8290a2}.hero,.panel,.problem-card,.landing-card{background:var(--paper);border:1px solid var(--line);border-radius:14px}.hero{padding:28px;margin-bottom:20px}.hero h1{margin:0 0 8px;font-size:clamp(1.7rem,5vw,2.35rem);line-height:1.25}.hero p{margin:0;color:var(--muted)}.panel{padding:22px;margin:20px 0}.settings{display:flex;flex-wrap:wrap;gap:18px;align-items:end}.setting label{display:block;font-weight:700;margin-bottom:5px}select,button,input{font:inherit}select{min-height:44px;padding:6px 10px;border:1px solid #9aa9bc;border-radius:8px;background:#fff}button,.button{min-height:46px;padding:9px 17px;border:0;border-radius:9px;background:var(--study);color:#fff;font-weight:750;cursor:pointer;text-decoration:none;display:inline-flex;align-items:center;justify-content:center}button.secondary{background:#e8f0ff;color:#164d9b}button:focus-visible,a:focus-visible,input:focus-visible,select:focus-visible{outline:3px solid #f59e0b;outline-offset:3px}.problem-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:14px}.problem-card{padding:17px}.problem-card label{display:flex;align-items:center;gap:10px;font-size:1.25rem}.problem-number{display:inline-grid;place-items:center;width:29px;height:29px;border-radius:50%;background:#e8f0ff;color:#164d9b;font-size:.85rem}.answer-input{width:100%;min-height:52px;margin-top:12px;padding:8px 12px;border:2px solid #aebdce;border-radius:9px;font-size:1.3rem}.answer-status{font-weight:800;margin:10px 0 0}.is-correct{color:#087a45}.is-incorrect{color:#bd2435}.session-actions{display:flex;flex-wrap:wrap;gap:10px;margin:20px 0}.result{border-color:#b7d2ff;background:#f8fbff}.summary{font-size:1.16rem}.print-settings{display:flex;flex-wrap:wrap;gap:14px;align-items:center}.landing-grid{display:grid;gap:14px}.landing-card{padding:20px;text-decoration:none;color:inherit}.landing-card:hover{border-color:#7aa8ef;box-shadow:0 4px 16px #1d4ed81a}.landing-card h2{margin:0 0 5px;color:#164d9b}.landing-card p{margin:0;color:var(--muted)}.print-only{display:none}@media(max-width:600px){.wrap{width:min(100% - 24px,960px)}.study-nav{display:none}.hero,.panel{padding:18px}.problem-grid{grid-template-columns:1fr}.settings,.print-settings{align-items:stretch}.setting,select,button{width:100%}}@media print{@page{size:A4 portrait;margin:14mm}body{background:#fff;font-size:11pt}.no-print,.study-header,.breadcrumbs,.settings-panel,.print-panel,.session-actions,.answer-status,.result{display:none!important}main{padding:0}.wrap{width:100%}.hero{border:0;padding:0;margin:0 0 10mm}.hero p{display:none}.problem-grid{grid-template-columns:repeat(2,1fr);gap:7mm}.problem-card{border:1px solid #777;padding:5mm;break-inside:avoid}.answer-input{border:0;border-bottom:1px solid #333;border-radius:0;min-height:12mm}html[data-print-mode="questions-answers"] .answer-input{font-size:0}html[data-print-mode="questions-answers"] .answer-input:after{content:""}html[data-print-mode="questions-answers"] .problem-card::after{content:"答え：" attr(data-answer)}html[data-print-mode="answers-page"] .problem-grid{page-break-after:always}html[data-print-name="true"] .print-only,html[data-print-date="true"] .print-only{display:block}.print-fields{display:flex;justify-content:flex-end;gap:12mm;margin-bottom:6mm}.print-answer-key{display:none}html[data-print-mode="answers-page"] .print-answer-key{display:block;page-break-before:always}.print-answer-key li{margin:4mm 0}}
/* Scope hidden-state safety to Study pages. */
.study-header ~ main [hidden],
main [hidden] {
  display: none !important;
}