/* あそびひろば 各クイズページの解説セクション（全ページ共通・色は中立） */
.study{
  max-width:760px;margin:26px auto 40px;padding:0 16px;
  font-family:'Hiragino Kaku Gothic ProN','Hiragino Sans','Yu Gothic',sans-serif;
  text-align:left;
}
.study-card{
  background:#fff;border:1px solid #E3E3EA;border-radius:16px;
  padding:24px 22px;box-shadow:0 2px 10px rgba(20,20,30,.05);
  color:#2A2A33;
}
.study h2{
  font-size:18px;font-weight:800;margin:0 0 12px;color:#1F2430;
  padding-left:11px;border-left:5px solid #94A3B8;line-height:1.6;
}
.study h3{font-size:15.5px;font-weight:800;margin:22px 0 8px;color:#1F2430}
.study p{font-size:15px;line-height:2.0;margin:0 0 14px;color:#3C4250}
.study ul{margin:0 0 14px;padding-left:20px}
.study li{font-size:15px;line-height:1.95;margin:7px 0;color:#3C4250}
.study strong{font-weight:800;color:#1F2430}
.study-foot{
  font-size:13px;line-height:1.9;color:#6B7280;
  border-top:1px solid #EDEDF2;padding-top:14px;margin:18px 0 0
}
.study-foot a{color:#0F766E;font-weight:700;text-decoration:none;border-bottom:1px solid #99D6D0}
.study-foot a:hover{opacity:.75}
@media (max-width:520px){
  .study{margin:20px auto 30px;padding:0 13px}
  .study-card{padding:19px 16px;border-radius:14px}
  .study h2{font-size:16.5px}
  .study h3{font-size:14.5px}
  .study p,.study li{font-size:14.5px}
}

/* 答えと解説の一覧 */
.study details{border:1px solid #E3E3EA;border-radius:12px;padding:0;margin:18px 0 0;background:#FAFAFB}
.study summary{
  cursor:pointer;padding:15px 18px;font-size:15px;font-weight:800;color:#1F2430;
  list-style:none;display:flex;align-items:center;gap:8px;min-height:48px;
}
.study summary::-webkit-details-marker{display:none}
.study summary::before{content:"▶";font-size:11px;color:#94A3B8;transition:transform .2s}
.study details[open] summary::before{transform:rotate(90deg)}
.study details > div{padding:0 18px 8px}
.qa{border-top:1px solid #EDEDF2;padding:14px 0}
.qa-q{font-size:14.5px;font-weight:800;color:#1F2430;line-height:1.85;margin:0 0 6px}
.qa-a{font-size:14px;line-height:1.85;margin:0 0 5px;color:#0F766E;font-weight:700}
.qa-e{font-size:13.5px;line-height:1.9;margin:0;color:#5A6070}
@media (max-width:520px){
  .study summary{font-size:14px;padding:13px 15px}
  .study details > div{padding:0 15px 6px}
  .qa-q{font-size:14px} .qa-a{font-size:13.5px} .qa-e{font-size:13px}
}

/* スマホ最適化（2026-09-07）: bodyがflex横並びのため .study が細くなるのを防ぐ */
@media (max-width: 768px){
  body{flex-wrap:wrap;}
  .study{flex:0 0 100%;width:100%;box-sizing:border-box;padding:0;}
  .study-card{padding:18px 15px;}
  .study p,.study li,.qa-a,.qa-e{font-size:15.5px;line-height:1.9;}
  .study h2{font-size:19px;}
  .study h3{font-size:16.5px;}
  .study summary{padding:12px 14px;}
}