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16px}.checkout-plan-banner{border-radius:var(--radius);padding:16px;display:flex;align-items:center;gap:14px;margin-bottom:24px}.checkout-plan-banner.phys{background:var(--phys-dim);border:1px solid rgba(56,189,248,.25)}.checkout-plan-banner.chem{background:var(--chem-dim);border:1px solid rgba(16,185,129,.25)}.checkout-plan-banner.bundle{background:var(--bundle-dim);border:1px solid rgba(245,158,11,.25)}.checkout-plan-icon{font-size:28px}.checkout-plan-name{font-size:15px;font-weight:700}.checkout-plan-price{font-size:13px;color:var(--muted2)}.form-group{margin-bottom:16px}.form-label{display:block;font-size:13px;font-weight:600;color:var(--muted2);margin-bottom:6px;letter-spacing:.3px}.form-input{width:100%;padding:14px 16px;background:var(--surface);border:1.5px solid var(--border);border-radius:var(--radius-sm);color:var(--text);font-size:15px;outline:0;transition:border-color 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var(--border);border-radius:var(--radius);overflow:hidden}.diagram-title{font-size:13px;font-weight:700;color:#0f172a;padding:10px 14px 4px}.diagram-desc{font-size:12px;color:#64748b;padding:0 14px 8px;line-height:1.5}.diagram-board{width:100%;height:240px;background:#fff;display:block}.diagram-board .JXGtext{color:#1e293b!important}.jxgbox{border:none!important;background:#fff!important}.item-card-formula .katex-display{display:inline;margin:0}.promo-banner{display:flex;align-items:center;justify-content:center;gap:8px;background:linear-gradient(135deg,rgba(245,158,11,.18),rgba(239,100,23,.14));border:1px solid rgba(245,158,11,.35);border-radius:12px;padding:10px 16px;margin:0 16px 12px;animation:2.4s ease-in-out infinite promo-pulse}@keyframes promo-pulse{0%,100%{box-shadow:0 0 0 0 rgba(245,158,11,0)}50%{box-shadow:0 0 12px 2px rgba(245,158,11,.22)}}.promo-banner-fire{font-size:18px;line-height:1;flex-shrink:0}.promo-banner-text{font-size:13px;font-weight:700;color:#fbbf24;text-align:center;flex:1}.promo-banner-end{font-size:11px;font-weight:500;color:rgba(251,191,36,.65);white-space:nowrap;flex-shrink:0}.item-card-formula .katex{font-size:1em}.cbt-mode-row{display:flex;gap:8px;padding:14px 16px 0}.cbt-mode-btn{flex:1;padding:10px 0;border-radius:var(--radius-sm);border:1.5px solid var(--border);background:var(--card);color:var(--muted2);font-size:13px;font-weight:700;transition:.18s}.cbt-mode-btn.active{background:var(--phys-dim);border-color:var(--phys);color:var(--phys)}.cbt-mode-desc{font-size:12px;color:var(--muted);text-align:center;padding:7px 16px 0;min-height:20px}.cbt-special-card{display:flex;align-items:center;gap:14px;background:linear-gradient(135deg,rgba(56,189,248,.08),rgba(56,189,248,.03));border:1.5px solid rgba(56,189,248,.25);border-radius:var(--radius);padding:14px 16px;margin:14px 16px 0;cursor:pointer;transition:background .15s}body.light .cbt-special-card{background:linear-gradient(135deg,rgba(2,132,199,.08),rgba(2,132,199,.03));border-color:rgba(2,132,199,.2)}body.light .cbt-q-dot{background:#fff;border-color:rgba(0,0,0,.22);color:#475569}body.light .cbt-q-dot.ans{background:var(--primary);border-color:var(--primary);color:#fff}body.light .cbt-q-dot.cur{background:#fff;border:3px solid var(--primary);color:var(--primary);box-shadow:0 0 0 2px color-mix(in srgb,var(--primary) 20%,transparent)}body.light .cbt-q-dot.ans.cur{background:var(--primary);border:3px solid var(--primary);color:#fff;box-shadow:0 0 0 3px color-mix(in srgb,var(--primary) 30%,transparent)}body.light .cbt-nav-bar{background:rgba(255,255,255,.97);border-top:1px solid rgba(0,0,0,.1)}.cbt-special-card:active{opacity:.75}.cbt-special-icon{font-size:26px;flex-shrink:0}.cbt-special-body{flex:1;min-width:0}.cbt-special-title{font-size:14px;font-weight:700;color:var(--text);margin-bottom:2px}.cbt-special-desc{font-size:12px;color:var(--muted)}.cbt-special-chevron{font-size:24px;color:var(--phys);font-weight:300;flex-shrink:0;line-height:1}.cbt-section-label{font-size:11px;font-weight:700;color:var(--muted);text-transform:uppercase;letter-spacing:.07em;padding:18px 16px 8px}.cbt-year-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:10px;padding:0 16px 28px}.cbt-year-btn{display:flex;flex-direction:column;align-items:center;justify-content:center;gap:2px;padding:14px 0 12px;border-radius:var(--radius-sm);border:1.5px solid var(--border);background:var(--card);cursor:pointer;transition:background .15s,border-color .15s,transform 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14px;margin-bottom:16px}.cbt-q-header{display:flex;align-items:baseline;gap:6px;margin-bottom:12px}.cbt-q-num{font-size:13px;font-weight:800;color:var(--phys)}.cbt-q-of{font-size:11px;color:var(--muted);font-weight:500}.cbt-q-text{font-size:15px;line-height:1.7;color:var(--text)}.cbt-diagram-board{margin:12px 0;border-radius:8px;overflow:hidden;border:1px solid var(--border)}.cbt-options{display:flex;flex-direction:column;gap:10px;margin-top:16px}.cbt-option{display:flex;align-items:center;gap:12px;padding:13px 14px;min-height:52px;border-radius:var(--radius-sm);border:1.5px solid var(--border);background:var(--surface);cursor:pointer;font-size:14px;font-weight:500;color:var(--text);transition:background .12s,border-color .12s,transform 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.cbt-option-letter{border-color:var(--success);color:var(--success)}.cbt-option.disabled{cursor:default}.cbt-option.selected{border-color:var(--primary);background:color-mix(in srgb,var(--primary) 8%,transparent)}.cbt-option.selected .cbt-option-letter{border-color:var(--primary);background:var(--primary);color:#fff}.cbt-feedback{display:flex;align-items:center;gap:10px;margin-top:14px;padding:12px 14px;border-radius:var(--radius-sm);font-size:14px;font-weight:600;animation:.2s fadeIn}.cbt-feedback-icon{font-size:18px;flex-shrink:0;line-height:1}.cbt-feedback.correct{background:rgba(34,197,94,.12);color:var(--success);border:1px solid rgba(34,197,94,.3)}.cbt-feedback.wrong{background:rgba(239,68,68,.08);color:var(--danger);border:1px solid rgba(239,68,68,.22)}.cbt-feedback.practice-saved{background:var(--card);color:var(--muted2);border:1px solid var(--border);font-size:12px;font-weight:500}.cbt-suggested-note{display:flex;align-items:flex-start;gap:8px;margin-top:8px;padding:10px 14px;border-radius:var(--radius-sm);background:rgba(234,179,8,.1);border:1px solid rgba(234,179,8,.35);color:var(--text);font-size:13px;line-height:1.5}.cbt-suggested-icon{font-size:16px;flex-shrink:0;margin-top:1px}.cbt-explanation{margin-top:12px;border-radius:var(--radius-sm);border:1px solid var(--border);background:var(--card);overflow:hidden}.cbt-explanation-label{font-size:11px;font-weight:700;letter-spacing:.05em;text-transform:uppercase;color:var(--muted);padding:8px 14px 6px;border-bottom:1px solid var(--border)}.cbt-explanation-body{padding:12px 14px;font-size:14px;line-height:1.75;color:var(--text)}.cbt-explanation-body strong{font-weight:700}.cbt-explanation-body ol,.cbt-explanation-body ul{padding-left:18px;margin:6px 0}.cbt-explanation-body li{margin-bottom:4px}.cbt-nav-bar{border-top:1px solid var(--border);background:var(--topbar-bg);backdrop-filter:blur(16px);-webkit-backdrop-filter:blur(16px);flex-shrink:0;padding:0 0 var(--safe-bottom)}.cbt-q-strip{display:flex;flex-direction:row;align-items:center;gap:6px;overflow-x:auto;padding:10px 12px;scrollbar-width:none}.cbt-q-strip::-webkit-scrollbar{display:none}.cbt-q-dot{flex-shrink:0;width:34px;height:34px;border-radius:50%;border:1.5px solid var(--border);background:0 0;color:var(--muted);font-size:11px;font-weight:700;cursor:pointer;display:flex;align-items:center;justify-content:center;padding:0;transition:background .15s,border-color .15s,color .15s}.cbt-q-dot.ans{background:var(--primary);border-color:var(--primary);color:#fff}.cbt-q-dot.cur{background:0 0;border:3px solid var(--primary);color:var(--primary);box-shadow:0 0 0 2px color-mix(in srgb,var(--primary) 25%,transparent)}.cbt-q-dot.ans.cur{background:var(--primary);border:3px solid var(--primary);color:#fff;box-shadow:0 0 0 3px color-mix(in srgb,var(--primary) 35%,transparent)}.cbt-q-dot.cbt-q-submit{background:var(--success,#22c55e);border-color:var(--success,#22c55e);color:#fff;font-size:13px;min-width:44px;border-radius:17px}.cbt-timer{font-size:13px;font-weight:800;font-variant-numeric:tabular-nums;color:var(--phys);padding:5px 9px;border-radius:8px;border:1.5px solid var(--phys);background:var(--phys-dim);flex-shrink:0;letter-spacing:.02em}.cbt-timer.warn{color:var(--danger);border-color:var(--danger);background:rgba(239,68,68,.1);animation:1s ease-in-out infinite timer-pulse}@keyframes timer-pulse{0%,100%{opacity:1}50%{opacity:.65}}.cbt-results-wrap{padding:20px 16px 48px;display:flex;flex-direction:column;gap:14px}.cbt-results-hero{text-align:center;padding:16px 0 8px}.cbt-results-emoji{font-size:56px;line-height:1;margin-bottom:10px}.cbt-results-title{font-size:24px;font-weight:900;color:var(--text);margin-bottom:4px}.cbt-results-year{font-size:13px;color:var(--muted2);font-weight:500}.cbt-score-card{background:var(--card);border:1px solid var(--border);border-radius:var(--radius);padding:20px 16px}.cbt-score-row{display:flex;align-items:center;justify-content:space-around;gap:12px;text-align:center}.cbt-score-val{font-size:36px;font-weight:900;color:var(--phys);line-height:1}.cbt-score-denom{font-size:18px;font-weight:500;color:var(--muted)}.cbt-score-label{font-size:11px;color:var(--muted);font-weight:600;text-transform:uppercase;letter-spacing:.04em;margin-top:4px}.cbt-grade-badge{font-size:36px;font-weight:900;border:3px solid;border-radius:12px;width:60px;height:60px;display:flex;align-items:center;justify-content:center;flex-shrink:0}.cbt-results-breakdown{display:flex;flex-direction:column;gap:8px}.cbt-breakdown-row{display:flex;align-items:center;justify-content:space-between;background:var(--card);border:1px solid var(--border);border-radius:var(--radius-sm);padding:12px 14px;font-size:13px}.cbt-breakdown-label{color:var(--muted2);font-weight:500}.cbt-breakdown-val{color:var(--text);font-weight:700}.cbt-results-btn{width:100%;padding:14px;border-radius:var(--radius-sm);border:none;background:var(--phys);color:#fff;font-size:15px;font-weight:700;cursor:pointer}.cbt-results-btn:active{opacity:.85}.cbt-results-btn-ghost{background:var(--card);color:var(--text);border:1.5px solid!important;margin-top:8px}.cbt-repeated-list{display:flex;flex-direction:column;gap:12px;padding:4px 0 28px}.cbt-rep-card{background:var(--card);border:1px solid var(--border);border-radius:var(--radius);padding:16px}.cbt-rep-concept{font-size:14px;font-weight:700;color:var(--text);margin-bottom:8px}.cbt-rep-formula{font-size:13px;color:var(--phys);margin-bottom:8px;overflow-x:auto;padding:6px 10px;background:var(--phys-dim);border-radius:6px}.cbt-rep-note{font-size:12px;color:var(--muted2);line-height:1.6;margin-bottom:10px;padding:6px 0;border-top:1px solid var(--border)}.cbt-rep-occ{display:flex;flex-direction:column;gap:6px}.cbt-rep-occ-item{font-size:12px;color:var(--muted);padding:8px 10px;background:rgba(255,255,255,.04);border-radius:8px;line-height:1.55}body.light .cbt-rep-occ-item{background:rgba(0,0,0,.04)}.cbt-rep-year{font-weight:700;color:var(--phys);font-size:11px;margin-bottom:3px;text-transform:uppercase;letter-spacing:.04em}