.subject-layout{display:flex;gap:20px;min-height:500px;padding:0 5px;}.subject-sidebar{width:260px;min-width:260px;background:#f8f9fb;border-radius:12px;box-shadow:0 2px 12px rgba(0,0,0,0.06);padding:12px 0;position:sticky;top:90px;align-self:flex-start;max-height:calc(100vh - 110px);overflow-y:auto;}.sidebar-title{font-family:-apple-system,BlinkMacSystemFont,'Segoe UI',Roboto,Helvetica,Arial,sans-serif;font-size:0.7rem;font-weight:700;text-transform:uppercase;letter-spacing:1.2px;color:#999;padding:8px 20px 10px;margin:0;}.sidebar-section-item{display:flex;align-items:center;gap:12px;padding:12px 20px;cursor:pointer;border-left:3px solid transparent;transition:all 0.2s ease;position:relative;}.sidebar-section-item:hover{background:#f8f9fa;}.sidebar-section-item.active{background:#f0f7ff;border-left-color:#1976D2;}.sidebar-section-item.disabled-section{opacity:0.5;cursor:not-allowed;}.progress-ring{width:40px;height:40px;min-width:40px;position:relative;}.progress-ring svg{transform:rotate(-90deg);width:40px;height:40px;}.progress-ring .ring-bg{fill:none;stroke:#e9ecef;stroke-width:3;}.progress-ring .ring-fill{fill:none;stroke:#43A047;stroke-width:3;stroke-linecap:round;transition:stroke-dashoffset 0.5s ease;}.progress-ring .ring-text{position:absolute;top:50%;left:50%;transform:translate(-50%,-50%);font-size:0.6rem;font-weight:700;color:#555;}.sidebar-section-name{font-family:-apple-system,BlinkMacSystemFont,'Segoe UI',Roboto,Helvetica,Arial,sans-serif;font-size:0.88rem;font-weight:600;color:#333;line-height:1.3;white-space:nowrap;overflow:hidden;text-overflow:ellipsis;}.sidebar-section-item.active .sidebar-section-name{color:#1976D2;}.section-content-area{flex:1;min-width:0;}.section-panel{display:none;animation:panelFadeIn 0.25s ease;}.section-panel.active{display:block;}@keyframes panelFadeIn{from{opacity:0;transform:translateY(6px);}to{opacity:1;transform:translateY(0);}}.section-header{background:#fff;border-radius:12px;padding:18px 24px;margin-bottom:16px;box-shadow:0 2px 12px rgba(0,0,0,0.06);display:flex;align-items:center;justify-content:space-between;flex-wrap:wrap;gap:10px;}.section-header h4{margin:0;font-family:-apple-system,BlinkMacSystemFont,'Segoe UI',Roboto,Helvetica,Arial,sans-serif;font-size:1.15rem;font-weight:700;color:#333;}.section-header .completion-info{display:flex;align-items:center;gap:12px;font-family:-apple-system,BlinkMacSystemFont,'Segoe UI',Roboto,Helvetica,Arial,sans-serif;font-size:1.0rem;font-weight:400;color:#666;}.section-header .completion-bar{width:140px;height:8px;background:#e9ecef;border-radius:4px;overflow:hidden;}.section-header .completion-bar-fill{height:100%;background:linear-gradient(90deg,#43A047,#66BB6A);border-radius:4px;transition:width 0.4s ease;}.section-header .completion-pct{font-weight:700;color:#43A047;min-width:36px;text-align:right;}.section-prereq-msg{background:#fff3e0;color:#e65100;padding:10px 16px;border-radius:8px;font-size:0.85rem;margin-bottom:16px;font-weight:500;}.topic-buttons-area{display:flex;flex-wrap:wrap;gap:8px;margin-bottom:18px;}.topic-buttons-area .btn-topic{padding:6px 16px;border-radius:20px;font-size:0.8rem;font-weight:600;border:1px solid #dee2e6;background:#fff;color:#555;cursor:pointer;transition:all 0.2s ease;white-space:nowrap;}.topic-buttons-area .btn-topic:hover{border-color:#1976D2;color:#1976D2;background:#f0f7ff;}.topic-buttons-area .btn-topic.active-topic{background:#1976D2;color:#fff;border-color:#1976D2;}.topic-buttons-area .btn-recordings{padding:6px 16px;border-radius:20px;font-size:0.8rem;font-weight:600;border:1px solid #ff9800;background:#fff;color:#ff9800;cursor:pointer;transition:all 0.2s ease;}.topic-buttons-area .btn-recordings:hover,.topic-buttons-area .btn-recordings.active-topic{background:#ff9800;color:#fff;}.quiz-cards-area{display:grid;grid-template-columns:repeat(auto-fill,minmax(260px,1fr));gap:16px;}.quiz-card{background:#fff;border-radius:12px;box-shadow:0 2px 10px rgba(0,0,0,0.05);overflow:hidden;transition:transform 0.2s ease,box-shadow 0.2s ease;display:flex;flex-direction:column;}.quiz-card:hover{transform:translateY(-2px);box-shadow:0 6px 20px rgba(0,0,0,0.1);}.quiz-card-body{padding:18px;flex:1;}.quiz-card-title{font-size:0.95rem;font-weight:700;color:#333;margin:0 0 14px 0;line-height:1.3;}.quiz-card-stats{display:flex;gap:16px;margin-bottom:12px;}.quiz-stat{flex:1;}.quiz-stat-label{font-size:0.68rem;text-transform:uppercase;letter-spacing:0.5px;color:#999;margin-bottom:3px;}.quiz-stat-value{font-size:0.9rem;font-weight:700;color:#333;}.quiz-card-progress{height:5px;background:#e9ecef;border-radius:3px;overflow:hidden;margin-top:4px;}.quiz-card-progress-fill{height:100%;border-radius:3px;transition:width 0.4s ease;}.quiz-card-progress-fill.low{background:#e53935;}.quiz-card-progress-fill.mid{background:#ff9800;}.quiz-card-progress-fill.high{background:#43A047;}.quiz-card-footer{padding:12px 18px;border-top:1px solid #f0f0f0;display:flex;gap:8px;}.quiz-card-footer .btn-solve{flex:1;padding:8px 12px;border-radius:8px;font-size:0.8rem;font-weight:700;text-align:center;text-decoration:none;transition:all 0.2s ease;border:none;cursor:pointer;}.quiz-card-footer .btn-solve.solve-new{background:linear-gradient(135deg,#43A047 0%,#388E3C 100%);color:#fff;box-shadow:0 2px 6px rgba(67,160,71,0.3);}.quiz-card-footer .btn-solve.solve-new:hover{box-shadow:0 4px 12px rgba(67,160,71,0.4);transform:translateY(-1px);}.quiz-card-footer .btn-solve.solve-review{background:linear-gradient(135deg,#1976D2 0%,#1565C0 100%);color:#fff;box-shadow:0 2px 6px rgba(25,118,210,0.3);}.quiz-card-footer .btn-solve.solve-review:hover{box-shadow:0 4px 12px rgba(25,118,210,0.4);transform:translateY(-1px);}.quiz-card-footer .btn-bookmark{padding:8px 12px;border-radius:8px;font-size:0.78rem;font-weight:600;background:#fff8e1;color:#f9a825;border:1px solid #ffe082;text-decoration:none;transition:all 0.2s ease;white-space:nowrap;}.quiz-card-footer .btn-bookmark:hover{background:#fff3c4;}.recording-card{background:#fff;border-radius:12px;box-shadow:0 2px 10px rgba(0,0,0,0.05);padding:18px;text-align:center;}.recording-card a{font-size:0.95rem;font-weight:600;color:#1976D2;text-decoration:none;}.recording-card a:hover{text-decoration:underline;}.ebook-section{background:#fff;border-radius:12px;padding:20px 24px;margin-bottom:20px;box-shadow:0 2px 12px rgba(0,0,0,0.06);}.ebook-section h5{font-size:1rem;font-weight:700;margin:0 0 14px 0;color:#333;}.ebook-type-selector{display:flex;gap:12px;margin-bottom:16px;}.ebook-type-selector label{padding:6px 18px;border-radius:20px;font-size:0.8rem;font-weight:600;border:1px solid #dee2e6;background:#fff;color:#555;cursor:pointer;transition:all 0.2s ease;}.ebook-type-selector input[type="radio"]{display:none;}.ebook-type-selector input[type="radio"]:checked + label{background:#1976D2;color:#fff;border-color:#1976D2;}@media (max-width:991px){.subject-layout{flex-direction:column;gap:12px;}.subject-sidebar{width:100%;min-width:unset;position:relative;top:auto;max-height:none;display:flex;overflow-x:auto;overflow-y:hidden;padding:8px 12px;gap:6px;border-radius:10px;-webkit-overflow-scrolling:touch;}.sidebar-title{display:none;}.sidebar-section-item{flex-direction:column;gap:4px;padding:8px 14px;min-width:max-content;border-left:none;border-bottom:3px solid transparent;border-radius:8px;}.sidebar-section-item.active{border-left:none;border-bottom-color:#1976D2;background:#f0f7ff;}.progress-ring{width:32px;height:32px;min-width:32px;}.progress-ring svg{width:32px;height:32px;}.sidebar-section-name{font-size:0.75rem;}.section-header{padding:14px 16px;}.quiz-cards-area{grid-template-columns:1fr;}}@media (max-width:575px){.subject-layout{padding:0;}.section-header{flex-direction:column;align-items:flex-start;}.topic-buttons-area{overflow-x:auto;flex-wrap:nowrap;padding-bottom:6px;-webkit-overflow-scrolling:touch;}}