.study-tools-title{margin:22px 0 8px;color:#0d5267;font-size:1.05rem}
.study-tools-note{margin:0 0 10px;color:#536c77;font-size:.9rem}
.study-tool-nav{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:8px}
.study-tool-tab{min-height:48px;border:1px solid #b8d5dd;border-radius:11px;padding:10px 8px;background:#f2f9fa;color:#16495b;font:inherit;font-weight:800;cursor:pointer;touch-action:manipulation}
.study-tool-tab[aria-selected="true"]{border-color:#0d6579;background:#0d6579;color:#fff}
.study-tool-section{scroll-margin-top:12px}
.study-tool-section[hidden]{display:none}
.study-section-lead{margin:0 0 14px;color:#536c77;font-size:.92rem}
.study-list{display:grid;gap:10px}
.study-word,.study-sentence,.study-reverse{width:100%;border:1px solid #d6e4e8;border-radius:13px;background:#f8fcfc;color:#163342;text-align:left;padding:14px;font:inherit}
button.study-word,button.study-reverse{cursor:pointer;touch-action:manipulation}
.study-word:active,.study-reverse:active,.sentence-audio:active{transform:scale(.995)}
.study-word-head{display:flex;align-items:flex-start;justify-content:space-between;gap:10px}
.study-word-en,.study-sentence-en,.study-answer{font-weight:800;color:#113f51;overflow-wrap:anywhere}
.study-sound{flex:0 0 auto;color:#0d6579;font-size:.82rem;font-weight:800}
.study-word-ja,.study-sentence-ja{display:block;margin-top:5px;color:#435e69}
.study-example{display:block;margin-top:8px;padding-top:8px;border-top:1px dashed #c9dce1;color:#365864;font-size:.92rem}
.study-example-ja{display:block;margin-top:2px;color:#61757e}
.study-reverse{background:#fffaf0;border-color:#edd9ac}
.study-label{display:block;margin-bottom:6px;color:#94651b;font-size:.78rem;font-weight:900;letter-spacing:.05em}
.study-prompt{display:block;color:#384f59;font-weight:700}
.study-answer{display:block;margin-top:10px;padding-top:10px;border-top:1px dashed #dfc991}
.study-answer[hidden]{display:none}
.study-reverse[aria-expanded="true"]{background:#fff5dc;border-color:#d8ac4e}
.sentence-audio{min-height:44px;margin-top:10px;border:0;border-radius:9px;padding:8px 12px;background:#dff0f3;color:#0b5568;font:inherit;font-weight:800;cursor:pointer;touch-action:manipulation}
@media(min-width:720px){.study-tool-nav{grid-template-columns:repeat(4,minmax(0,1fr))}.study-vocab-list{grid-template-columns:repeat(2,minmax(0,1fr))}}