:root{--primary-color:#4a90e2;--primary-hover:#357abd;--primary-light:rgba(74,144,226,0.1);--success-color:#35c3a9;--success-light:rgba(53,195,169,0.1);--text-primary:#333;--text-secondary:#666;--bg-light:#f8f9fa;--card-bg:#ffffff;--card-border:#eaeaea;--card-shadow:0 5px 15px rgba(0,0,0,0.05);--sidebar-active:#f5f9ff;--sidebar-hover:#f0f7ff}.dark-mode{--text-primary:#fff;--text-secondary:#aaa;--bg-light:#1a1a1a;--card-bg:#2d2d2d;--card-border:#3d3d3d;--sidebar-active:#2a3a4a;--sidebar-hover:#252f3d}.lesson-container{padding:40px 0}.breadcrumb{background-color:transparent;padding-left:0}.breadcrumb-item a{color:var(--primary-color);text-decoration:none}.lesson-header{margin-bottom:30px}.lesson-title{font-size:2.2rem;font-weight:700;margin-bottom:15px;color:var(--text-primary)}.lesson-meta{display:flex;gap:20px;color:var(--text-secondary);margin-bottom:25px;font-size:0.9rem}.lesson-meta-item{display:flex;align-items:center;gap:5px}.progress-container{background-color:var(--card-bg);border-radius:10px;padding:20px;margin-bottom:30px;box-shadow:var(--card-shadow);border:1px solid var(--card-border)}.progress-bar-container{height:8px;background-color:var(--bg-light);border-radius:4px;overflow:hidden;margin-bottom:10px}.progress-bar{height:100%;background-color:var(--primary-color);border-radius:4px}.progress-text{display:flex;justify-content:space-between;color:var(--text-secondary);font-size:0.9rem}.lesson-content{background-color:var(--card-bg);border-radius:10px;padding:30px;margin-bottom:30px;box-shadow:var(--card-shadow);border:1px solid var(--card-border);line-height:1.7;color:var(--text-primary)}.lesson-content h2{font-size:1.6rem;font-weight:600;margin-top:30px;margin-bottom:20px;color:var(--text-primary)}.lesson-content h3{font-size:1.3rem;font-weight:600;margin-top:25px;margin-bottom:15px;color:var(--text-primary)}.lesson-content p{margin-bottom:20px}.lesson-content pre{background-color:var(--bg-light);padding:15px;border-radius:8px;overflow:auto;margin-bottom:20px}.lesson-content code{background-color:var(--bg-light);padding:2px 5px;border-radius:4px}.lesson-content ul,.lesson-content ol{margin-bottom:20px;padding-left:20px}.lesson-content li{margin-bottom:10px}.lesson-content img{max-width:100%;height:auto;border-radius:8px;margin:20px 0}.lesson-content table{width:100%;border-collapse:collapse;margin-bottom:20px}.lesson-content th,.lesson-content td{padding:12px 15px;border:1px solid var(--card-border)}.lesson-content th{background-color:var(--bg-light)}.lesson-content blockquote{border-left:4px solid var(--primary-color);padding-left:15px;margin-left:0;color:var(--text-secondary)}.lesson-navigation{display:flex;justify-content:space-between;margin-bottom:30px}.nav-button{display:flex;align-items:center;gap:10px;background-color:var(--card-bg);color:var(--text-primary);padding:12px 20px;border-radius:8px;border:1px solid var(--card-border);transition:all 0.2s;text-decoration:none}.nav-button:hover{background-color:var(--primary-light);color:var(--primary-color);text-decoration:none}.nav-button.next{background-color:var(--primary-color);color:white}.nav-button.next:hover{background-color:var(--primary-hover);color:white}.nav-button-icon{font-size:20px}.nav-button-text{display:flex;flex-direction:column}.nav-button-label{font-size:0.8rem;opacity:0.8}.nav-button-title{font-weight:500}.lesson-sidebar{position:sticky;top:20px;max-height:calc(100vh - 40px);overflow-y:auto}.sidebar-card{background-color:var(--card-bg);border-radius:10px;overflow:hidden;box-shadow:var(--card-shadow);border:1px solid var(--card-border);margin-bottom:20px}.sidebar-header{background-color:var(--primary-color);color:white;padding:15px 20px;font-size:1.1rem;font-weight:600;display:flex;justify-content:space-between;align-items:center}.sidebar-progress{display:flex;align-items:center;gap:10px;background-color:rgba(255,255,255,0.2);padding:4px 10px;border-radius:20px;font-size:0.8rem}.lesson-list{list-style:none;padding:0;margin:0}.lesson-item{border-bottom:1px solid var(--card-border)}.lesson-item:last-child{border-bottom:none}.lesson-link{display:flex;justify-content:space-between;align-items:center;padding:15px 20px;color:var(--text-primary);text-decoration:none;transition:all 0.2s}.lesson-link:hover{background-color:var(--sidebar-hover);color:var(--primary-color);text-decoration:none}.lesson-link.active{background-color:var(--sidebar-active);color:var(--primary-color);font-weight:500;border-left:3px solid var(--primary-color)}.lesson-link-content{display:flex;flex-direction:column;gap:5px}.lesson-number{font-size:0.8rem;color:var(--text-secondary)}.lesson-name{font-weight:500}.lesson-status{min-width:24px;height:24px;display:flex;align-items:center;justify-content:center}.lesson-status.current{background-color:var(--primary-light);color:var(--primary-color);border-radius:50%}.lesson-status.completed{background-color:var(--success-light);color:var(--success-color);border-radius:50%}.sidebar-cta{padding:20px;text-align:center}.sidebar-cta-title{font-size:1.1rem;font-weight:600;margin-bottom:10px;color:var(--text-primary)}.sidebar-cta-text{color:var(--text-secondary);margin-bottom:15px;font-size:0.9rem}.sidebar-cta-button{display:inline-block;background-color:var(--primary-color);color:white;padding:10px 20px;border-radius:6px;text-decoration:none;font-weight:500;transition:background-color 0.2s}.sidebar-cta-button:hover{background-color:var(--primary-hover);color:white;text-decoration:none}.recommend-section{margin-top:50px}.recommend-title{font-size:1.5rem;font-weight:600;margin-bottom:20px;color:var(--text-primary)}.recommend-course{background-color:var(--card-bg);border-radius:10px;overflow:hidden;box-shadow:var(--card-shadow);border:1px solid var(--card-border);transition:transform 0.3s ease}.recommend-course:hover{transform:translateY(-5px)}.recommend-course-body{padding:20px}.recommend-course-title{font-size:1.1rem;font-weight:600;margin-bottom:10px;color:var(--text-primary)}.recommend-course-title a{color:inherit;text-decoration:none}.recommend-course-title a:hover{color:var(--primary-color)}.recommend-course-description{color:var(--text-secondary);font-size:0.9rem}@media (max-width:991.98px){.lesson-sidebar{position:static;max-height:none;margin-bottom:30px}.lesson-navigation{flex-direction:column;gap:15px}}.content-core-links{--content-core-bg:#f8faf9;--content-core-surface:#ffffff;--content-core-border:#cbd5d1;--content-core-text:#17231f;--content-core-muted:#5d6b66;--content-core-accent:#2f6e54;background:var(--content-core-bg);border:1px solid var(--content-core-border);color:var(--content-core-text);margin:48px 0 0}html.dark-mode .content-core-links,body.dark-mode .content-core-links{--content-core-bg:#1b2320;--content-core-surface:#202a26;--content-core-border:#46544f;--content-core-text:#f0f7f4;--content-core-muted:#bac8c2;--content-core-accent:#9bcbb6}.content-core-links__header{border-bottom:1px solid var(--content-core-border);padding:28px 30px 26px}.content-core-links__eyebrow{color:var(--content-core-accent);font-size:0.75rem;font-weight:700;letter-spacing:0.1em;line-height:1.4;margin:0 0 10px;text-transform:uppercase}.content-core-links h2{color:var(--content-core-text);font-size:clamp(1.45rem,2.5vw,2rem);font-weight:700;line-height:1.2;margin:0}.content-core-links__intro{color:var(--content-core-muted);line-height:1.65;margin:12px 0 0;max-width:760px}.content-core-links__grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr))}.content-core-links__group{background:var(--content-core-surface);min-width:0;padding:24px 26px 26px}.content-core-links__group + .content-core-links__group{border-left:1px solid var(--content-core-border)}.content-core-links__group h3{color:var(--content-core-text);font-size:0.98rem;font-weight:700;line-height:1.35;margin:0 0 15px}.content-core-links__group p{color:var(--content-core-muted);line-height:1.55;margin:0 0 12px}.content-core-links__list{list-style:none;margin:0;padding:0}.content-core-links__list li + li{border-top:1px solid var(--content-core-border)}.content-core-links a{color:var(--content-core-accent);display:inline-block;font-weight:600;line-height:1.45;overflow-wrap:anywhere;padding:8px 0;text-decoration:none;text-underline-offset:0.2em}.content-core-links a:hover{text-decoration:underline}.content-core-links a:focus-visible{border-radius:2px;outline:3px solid var(--content-core-accent);outline-offset:3px}@media (max-width:767.98px){.content-core-links{margin-top:40px}.content-core-links__header{padding:24px 22px 22px}.content-core-links__grid{grid-template-columns:1fr}.content-core-links__group{padding:22px}.content-core-links__group + .content-core-links__group{border-left:0;border-top:1px solid var(--content-core-border)}}