:root{--dir-ink:#0d1622;--dir-ink-2:#132133;--dir-paper:#f8faf7;--dir-card:#ffffff;--dir-muted:#667085;--dir-line:rgba(13, 22, 34, .12);--dir-green:#176b4c;--dir-teal:#0f766e;--dir-gold:#d6a93e;--dir-blue:#315f8c}.dir-wrap{background:var(--dir-paper);color:var(--dir-ink)}.dir-shell{margin:0 auto;max-width:1180px;padding:0 24px}.dir-hero{background:linear-gradient(135deg,rgba(13,22,34,.98),rgba(20,41,56,.95)),linear-gradient(90deg,var(--dir-green),var(--dir-blue));color:#fff;padding:70px 0 50px;text-align:center}.dir-kicker{color:#5fd6b5;font-size:.78rem;font-weight:900;letter-spacing:.14em;margin:0 0 12px;text-transform:uppercase}.dir-hero h1{color:#fff;font-size:clamp(2.2rem,5vw,4rem);font-weight:900;letter-spacing:0;line-height:1.05;margin:0 auto 16px;max-width:880px}.dir-hero p{color:#d7e5e2;font-size:1.08rem;line-height:1.7;margin:0 auto;max-width:760px}.dir-meta-row{display:flex;flex-wrap:wrap;gap:10px;justify-content:center;margin-top:24px}.dir-meta-row span,.dir-back-link{background:rgba(255,255,255,9%);border:1px solid rgba(255,255,255,.16);border-radius:999px;color:#fff;font-size:.84rem;font-weight:850;padding:9px 12px;text-decoration:none}.dir-back-link:hover{background:rgba(255,255,255,.16);color:#fff}.dir-content{padding:58px 0 72px}.dir-prose{background:#fff;border:1px solid var(--dir-line);border-radius:8px;box-shadow:0 16px 34px rgba(13,22,34,6%);color:var(--dir-muted);line-height:1.75;margin:0 auto 34px;max-width:860px;padding:26px 30px;text-align:center}.dir-prose>*:first-child{margin-top:0}.dir-prose>*:last-child{margin-bottom:0}.dir-prose a{color:var(--dir-green);font-weight:850}.dir-grid{display:grid;gap:18px;grid-template-columns:repeat(3,minmax(0,1fr))}.dir-card{background:var(--dir-card);border:1px solid var(--dir-line);border-radius:8px;box-shadow:0 16px 34px rgba(13,22,34,7%);color:var(--dir-ink);display:grid;overflow:hidden;text-decoration:none;transition:box-shadow .2s ease,transform .2s ease,border-color .2s 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h3{color:var(--dir-ink);font-size:1.15rem;font-weight:900;letter-spacing:0;line-height:1.25;margin:0}.dir-card h2 a,.dir-card h3 a{color:inherit;text-decoration:none}.dir-card p{color:var(--dir-muted);font-size:.94rem;line-height:1.58;margin:0}.book-dir-actions{display:flex;flex-wrap:wrap;gap:8px;margin-top:4px}.book-dir-actions a{background:#fffaf0;border:1px solid rgba(214,169,62,.42);border-radius:999px;color:var(--dir-ink);font-size:.82rem;font-weight:900;padding:8px 11px;text-decoration:none}.book-dir-actions a:first-child{background:var(--dir-ink);border-color:var(--dir-ink);color:#fff}.book-dir-actions a:hover{transform:translateY(-1px)}.dir-card-link{color:var(--dir-green);font-size:.86rem;font-weight:900;margin-top:4px}.dir-empty{background:#fff;border:1px solid var(--dir-line);border-radius:8px;color:var(--dir-muted);padding:28px;text-align:center}.dir-pagination{margin-top:36px}.dir-pagination .pagination{justify-content:center}.dir-terms-grid{display:grid;gap:14px;grid-template-columns:repeat(4,minmax(0,1fr))}.dir-term-card{background:#fff;border:1px solid var(--dir-line);border-radius:8px;box-shadow:0 14px 28px rgba(13,22,34,6%);color:var(--dir-ink);display:grid;gap:8px;min-height:150px;padding:20px;text-align:center;text-decoration:none;transition:transform .2s ease,box-shadow .2s ease}.dir-term-card:hover{box-shadow:0 20px 38px rgba(13,22,34,.12);color:var(--dir-ink);transform:translateY(-3px)}.dir-term-card strong{font-size:1.05rem;line-height:1.25}.dir-term-card span{color:var(--dir-green);font-size:.82rem;font-weight:900;text-transform:uppercase}.ai-study-layout{background:var(--dir-paper);color:var(--dir-ink);padding:58px 0 72px}.ai-hub-flow{background:linear-gradient(180deg,#f8faf7 0,#eef5f1 45%,#f8faf7 100%);padding:58px 0 76px}.ai-hub-tabs{display:flex;flex-wrap:wrap;gap:10px;justify-content:center;margin:0 auto 42px;max-width:920px}.ai-hub-tabs a{background:#fff;border:1px solid var(--dir-line);border-radius:999px;box-shadow:0 12px 26px rgba(13,22,34,6%);color:var(--dir-ink);font-size:.86rem;font-weight:900;padding:11px 15px;text-decoration:none}.ai-hub-tabs a:hover{background:var(--dir-ink);color:#fff}.ai-hub-section{margin:0 auto 54px}.ai-hub-section:last-child{margin-bottom:0}.ai-hub-heading{margin:0 auto 24px;max-width:790px;text-align:center}.ai-hub-heading .dir-kicker{color:var(--dir-green)}.ai-hub-heading h2{color:var(--dir-ink);font-size:clamp(1.7rem,3vw,2.55rem);font-weight:900;letter-spacing:0;line-height:1.08;margin:0 0 12px}.ai-hub-heading p{color:var(--dir-muted);font-size:1rem;line-height:1.7;margin:0 auto}.ai-hub-teacher-grid{display:grid;gap:18px;grid-template-columns:repeat(3,minmax(0,1fr))}.ai-hub-teacher-card{background:#fff;border:1px solid var(--dir-line);border-radius:8px;box-shadow:0 16px 34px rgba(13,22,34,7%);color:var(--dir-ink);display:grid;overflow:hidden;text-decoration:none;transition:border-color .2s ease,box-shadow .2s ease,transform .2s ease}.ai-hub-teacher-card:hover{border-color:rgba(23,107,76,.28);box-shadow:0 22px 46px rgba(13,22,34,.13);color:var(--dir-ink);transform:translateY(-3px)}.ai-hub-teacher-media{aspect-ratio:16/9;background:radial-gradient(circle at 24% 18%,rgba(214,169,62,.28),transparent 30%),linear-gradient(135deg,var(--dir-ink-2),var(--dir-teal));display:block;overflow:hidden}.ai-hub-teacher-media img{display:block;height:100%;object-fit:cover;width:100%}.ai-hub-teacher-media span{align-items:center;color:#fff;display:flex;font-weight:900;height:100%;justify-content:center;padding:20px;text-align:center}.ai-hub-teacher-body{display:grid;gap:9px;padding:20px}.ai-hub-teacher-body strong{color:var(--dir-ink);display:block;font-size:1.14rem;font-weight:900;line-height:1.2}.ai-hub-teacher-body span:last-child{color:var(--dir-muted);font-size:.94rem;line-height:1.55}.ai-hub-topic-grid,.ai-hub-lesson-grid{display:grid;gap:14px;grid-template-columns:repeat(3,minmax(0,1fr))}.ai-hub-topic-card,.ai-hub-lesson-card{background:#fff;border:1px solid var(--dir-line);border-radius:8px;box-shadow:0 14px 28px rgba(13,22,34,6%);color:var(--dir-ink);display:grid;gap:9px;min-height:170px;padding:22px;text-align:center;text-decoration:none}.ai-hub-topic-card:hover{box-shadow:0 20px 38px rgba(13,22,34,.12);color:var(--dir-ink);transform:translateY(-3px)}.ai-hub-topic-card strong,.ai-hub-lesson-card strong{color:var(--dir-ink);font-size:1.08rem;font-weight:900;line-height:1.2}.ai-hub-topic-card span,.ai-hub-lesson-card p{color:var(--dir-muted);font-size:.94rem;line-height:1.55;margin:0}.ai-study-grid{display:grid;gap:18px;grid-template-columns:repeat(2,minmax(0,1fr));margin:0 auto 34px;max-width:980px}.ai-study-panel{background:#fff;border:1px solid var(--dir-line);border-top:5px solid var(--dir-green);border-radius:8px;box-shadow:0 16px 34px rgba(13,22,34,7%);padding:24px}.ai-study-panel:nth-child(2n){border-top-color:var(--dir-gold)}.ai-study-panel h2,.ai-study-panel h3{color:var(--dir-ink);font-size:1.24rem;letter-spacing:0;margin:0 0 10px}.ai-study-panel p,.ai-study-panel li{color:var(--dir-muted);line-height:1.65}.ai-study-panel ul{margin:0;padding-left:1.2rem}.ai-teacher-strip{display:grid;gap:14px;grid-template-columns:repeat(2,minmax(0,1fr));margin:0 auto;max-width:980px}.ai-teacher-link{align-items:center;background:#fff;border:1px solid var(--dir-line);border-radius:8px;box-shadow:0 14px 28px rgba(13,22,34,6%);color:var(--dir-ink);display:grid;gap:14px;grid-template-columns:86px 1fr;padding:16px;text-decoration:none}.ai-teacher-link:hover{color:var(--dir-ink);transform:translateY(-2px)}.ai-teacher-link img,.ai-teacher-thumb-fallback{aspect-ratio:1;border-radius:8px;object-fit:cover;width:86px}.ai-teacher-thumb-fallback{align-items:center;background:linear-gradient(135deg,var(--dir-green),var(--dir-blue));color:#fff;display:flex;font-weight:900;justify-content:center}.ai-teacher-link strong{display:block;margin-bottom:4px}.ai-teacher-link span{color:var(--dir-muted);font-size:.9rem;line-height:1.45}@media(max-width:980px){.dir-grid,.dir-terms-grid,.ai-hub-teacher-grid,.ai-hub-topic-grid,.ai-hub-lesson-grid{grid-template-columns:repeat(2,minmax(0,1fr))}}@media(max-width:720px){.dir-shell{padding:0 18px}.dir-hero{padding:48px 0 40px}.dir-content,.ai-study-layout,.ai-hub-flow{padding:42px 0 56px}.dir-grid,.dir-terms-grid,.ai-study-grid,.ai-teacher-strip,.ai-hub-teacher-grid,.ai-hub-topic-grid,.ai-hub-lesson-grid{grid-template-columns:1fr}.dir-prose{padding:22px}.ai-teacher-link{grid-template-columns:68px 1fr}.ai-teacher-link img,.ai-teacher-thumb-fallback{width:68px}}