/* ATAWI一次方程式 — 憲法 §11 デザイン規約。明朝を使わない。字間（レタースペーシング）を空けない。 */
:root{
  --c-primary:#1f4e79; --c-accent:#d08000; --c-accent-text:#9c5e00; --c-warn:#c0504d;
  --c-bg:#ffffff; --c-text:#222222; --c-muted:#666666; --c-panel:#e8eff7; --c-reason-bg:#fff8ec;
  --c-A:#1f4e79; --c-B:#2e7d32; --c-C:#6a1b9a; --c-D:#9c5e00; --c-E:#00695c; --c-F:#8d6e63;
  --font:"BIZ UDPGothic","Hiragino Sans","Hiragino Kaku Gothic ProN","Noto Sans JP","Noto Sans CJK JP","Yu Gothic","Meiryo",system-ui,sans-serif;
  --fs-base:1rem; --lh:1.75; --w-main:720px;
}
*{box-sizing:border-box}
html{font-size:16px}
body{margin:0;font-family:var(--font);font-size:var(--fs-base);line-height:var(--lh);color:var(--c-text);background:var(--c-bg);overflow-x:hidden}
a{color:var(--c-primary)}
.site-header{display:flex;align-items:center;justify-content:space-between;gap:8px;padding:10px 16px;border-bottom:3px solid var(--c-primary);flex-wrap:wrap}
.brand{font-weight:700;text-decoration:none;font-size:1.1rem}
.global a{margin-left:12px;font-size:1rem}
.main{max-width:var(--w-main);margin:0 auto;padding:16px}
.site-footer{max-width:var(--w-main);margin:32px auto 0;padding:16px;border-top:1px solid #ccc;font-size:1rem}
.site-footer a{margin-right:12px}
.small{font-size:1rem;color:var(--c-muted)}
h1{font-size:1.5rem;color:var(--c-primary);margin:.5rem 0 1rem}
h2{font-size:1.15rem;color:var(--c-primary);background:var(--c-panel);border-left:5px solid var(--c-primary);padding:4px 10px;margin:1.5rem 0 .6rem}
blockquote{margin:1rem 0;padding:8px 14px;border-left:4px solid var(--c-accent);background:var(--c-reason-bg)}
.btn{display:inline-block;padding:10px 16px;background:var(--c-primary);color:#fff;border:0;border-radius:6px;text-decoration:none;font-size:1rem;cursor:pointer;margin:4px 4px 4px 0}
.btn.secondary{background:#fff;color:var(--c-primary);border:2px solid var(--c-primary)}
button{font-family:inherit;font-size:1rem}
table{border-collapse:collapse;width:100%;margin:.5rem 0 1rem}
th,td{border:1px solid #999;padding:6px 8px;text-align:left;vertical-align:top}
th{background:var(--c-panel);color:var(--c-primary)}
.cards{list-style:none;padding:0;margin:0}
.cards li{border:1px solid #ccc;border-radius:6px;margin:6px 0}
.cards a{display:block;padding:10px;text-decoration:none;color:inherit}
.stars{color:var(--c-accent-text)}
.adv{color:#fff;background:var(--c-warn);padding:0 6px;border-radius:4px;font-size:1rem}
.draft{color:var(--c-muted);border:1px solid var(--c-muted);padding:0 6px;border-radius:4px;font-size:1rem}
.tag{display:inline-block;margin-left:6px;padding:0 6px;border:1px solid var(--c-accent);color:var(--c-accent-text);border-radius:4px;font-size:1rem}
.note{color:var(--c-muted);font-size:1rem}
/* 7つの動詞 */
.verbs{display:flex;flex-wrap:wrap;gap:4px;list-style:none;padding:0;margin:.5rem 0 1rem;counter-reset:v}
.verbs li{counter-increment:v;padding:4px 10px;border:1px solid var(--c-primary);border-radius:14px;font-size:1rem;background:#fff}
.verbs li::before{content:counter(v) ". ";color:var(--c-primary);font-weight:700}
.verbs li[aria-current=step]{background:var(--c-primary);color:#fff}
.verbs li a{text-decoration:none;color:inherit}
/* 1問ページ */
.problem .meta{color:var(--c-muted);margin:0 0 .4rem}
.statement{font-size:1.1rem;padding:12px;border:2px solid var(--c-primary);border-radius:8px;background:#fff}
.mode-switch{margin:.6rem 0}
.mode-switch button{padding:8px 12px;margin-right:6px;border:2px solid var(--c-primary);background:#fff;color:var(--c-primary);border-radius:6px;cursor:pointer}
.mode-switch button[aria-pressed=true]{background:var(--c-primary);color:#fff}
.sec{border-top:1px solid #ddd;padding:6px 0 10px}
.sec h2{margin-top:.6rem}
.sec-connect{background:var(--c-panel);padding:8px 12px;border-radius:8px}
.reason{padding:8px 12px;border-left:4px solid var(--c-accent);background:var(--c-reason-bg);font-weight:700}
.equation{font-size:1.4rem;font-weight:700;margin:.4rem 0}
.verbs-list li{margin:.25rem 0}
.five-questions{padding-left:1.6em}
.five-questions li{margin:.6rem 0;padding:8px 12px;border:2px solid var(--c-primary);border-radius:8px;background:#fff}
.pattern{display:inline-block;padding:2px 10px;border-radius:12px;color:#fff;font-weight:700;font-size:1rem;background:var(--c-primary)}
.pattern-A{background:var(--c-A)}.pattern-B{background:var(--c-B)}.pattern-C{background:var(--c-C)}.pattern-D{background:var(--c-D)}.pattern-E{background:var(--c-E)}.pattern-F{background:var(--c-F)}
.answer{font-size:1.3rem;font-weight:700;color:var(--c-primary)}
.judgment{padding:8px 12px;border:2px solid var(--c-warn);border-radius:6px}
.steps li{font-size:1.1rem}
.try-row{margin:.5rem 0 1rem;padding:8px;border:1px dashed var(--c-accent);border-radius:6px}
.try-table{font-size:1rem}
.try-input input{font-size:1.1rem;padding:6px;width:8em}
.reason-input{width:100%;font-family:inherit;font-size:1rem;padding:8px}
details.mistake{border:1px solid #ccc;border-radius:6px;padding:6px 10px;margin:.4rem 0}
details.mistake summary{cursor:pointer;font-weight:700}
code{background:#f0f0f0;padding:0 .3em;font-family:inherit}
figure{margin:0}
figcaption{font-size:1rem;color:var(--c-muted);margin-top:.3rem}
.next{margin:1.2rem 0}
.reveal-next{margin:.8rem 0}
@media (max-width:599px){
  .triple thead{display:none}
  .triple tr{display:block;border:1px solid #999;margin-bottom:6px}
  .triple td{display:block;border:0;border-bottom:1px solid #ddd;padding:4px 8px}
  .triple td::before{content:attr(data-th) "：";color:var(--c-primary);font-weight:700}
  .triple td:empty{display:none}
  .global a{margin-left:8px;font-size:1rem}
}
/* 1問ページ：JS が形式を決めるまでの間、画面が出る前に隠しておく（画面のずれを防ぐ。reveal.js が js-pending を外す） */
html.js-pending[data-start-mode=c] article.problem .sec[data-step]{display:none}
html.js-pending[data-start-mode=b] article.problem #sec-6 .blank{display:none}
.problem-title{font-size:1.2rem;margin:.2rem 0 .4rem}