.study-directory{gap:28px;display:grid}.tool-directory-grid{grid-template-columns:repeat(3,minmax(0,1fr));gap:16px;display:grid}.tool-directory-card{border:1px solid var(--line);border-radius:var(--radius);background:var(--panel);min-height:190px;padding:22px;text-decoration:none}.tool-directory-card.is-available{box-shadow:var(--shadow);border-color:#b8dcd4}.tool-directory-card>span{color:var(--brand);text-transform:uppercase;font-size:.76rem;font-weight:800}.tool-directory-card h2{margin:10px 0 8px;font-size:1.15rem}.tool-directory-card p{color:var(--muted)}.tool-directory-card strong{color:var(--brand-dark)}.study-tool-shell{gap:18px;display:grid}.tool-status-row,.tool-action-row{flex-wrap:wrap;justify-content:space-between;align-items:center;gap:12px;display:flex}.tool-status-row{color:var(--muted);font-size:.86rem}.flashcard{border:1px solid var(--line);border-radius:var(--radius-lg);background:var(--panel);cursor:pointer;min-height:360px;box-shadow:var(--shadow);align-content:center;place-items:center;gap:14px;padding:34px;display:grid}.flashcard strong{font-family:Noto Sans SC,sans-serif;font-size:clamp(3.4rem,10vw,6.5rem);line-height:1}.flashcard .reference-pinyin{color:var(--brand-dark);font-size:1.25rem;font-weight:750}.flashcard-answer{min-height:26px;color:var(--muted);font-size:1rem}.reading-practice-list{gap:22px;display:grid}.reading-passage-card{border:1px solid var(--line);border-radius:var(--radius);background:var(--panel);padding:26px}.reading-passage-card header span{color:var(--brand);text-transform:uppercase;font-size:.75rem;font-weight:800}.reading-passage-card h2{margin:6px 0 18px}.reading-text{background:#f8faf9;border-radius:14px;padding:18px}.reading-text p{margin:0 0 10px}.reading-chinese{font-family:Noto Sans SC,sans-serif;font-size:1.35rem;line-height:1.8}.reading-question-list{gap:18px;margin-top:22px;display:grid}.reading-question-list section{border-top:1px solid var(--line);padding-top:18px}.reading-question-list h3{font-size:1rem}.reading-choices{grid-template-columns:repeat(3,minmax(0,1fr));gap:9px;display:grid}.reading-choices button,.calculator-questions button{border:1px solid var(--line);cursor:pointer;background:#fafcfb;border-radius:10px;min-height:44px;padding:10px 12px}.reading-choices button.selected,.calculator-questions button.selected{border-color:var(--brand);background:var(--brand-soft)}.reading-choices button.correct{background:#e8f7ef;border-color:#2f946c}.reading-choices button.wrong{background:#fff0f0;border-color:#cf6262}.reading-check{cursor:pointer;background:0 0;border:0;margin-top:10px}.reading-explanation{color:var(--muted)}.calculator-layout{grid-template-columns:minmax(0,1.4fr) minmax(280px,.6fr);align-items:start;gap:22px;display:grid}.calculator-questions{gap:12px;display:grid}.calculator-questions fieldset{border:1px solid var(--line);background:var(--panel);border-radius:14px;margin:0;padding:20px}.calculator-questions legend{padding:0 6px;font-weight:740}.calculator-questions fieldset>div{grid-template-columns:repeat(3,1fr);gap:8px;margin-top:12px;display:grid}.calculator-result{border:1px solid var(--line);border-radius:var(--radius);background:var(--panel);box-shadow:var(--shadow);padding:24px;position:sticky;top:92px}.calculator-result h2{margin:7px 0}.calculator-result small{color:var(--muted);margin-top:14px;display:block}@media (max-width:820px){.tool-directory-grid{grid-template-columns:repeat(2,minmax(0,1fr))}.calculator-layout{grid-template-columns:1fr}.calculator-result{position:static}}@media (max-width:560px){.tool-directory-grid,.reading-choices,.calculator-questions fieldset>div{grid-template-columns:1fr}.tool-action-row .button{flex:42%}.flashcard{min-height:300px}}