.sidebar-nav{list-style:none;padding:0 20px;margin:0}.sidebar-nav-item{margin-bottom:8px}.sidebar-nav-link{display:block;padding:10px 15px;color:#333;border-radius:6px;text-decoration:none;font-weight:500;transition:background .2s,color .2s}.sidebar-nav-link.active,.sidebar-nav-link:hover{background:var(--primary-color);color:#fff}.sidebar-toggle{display:none}@media (max-width:768px){.grammar-sidebar{display:none}.sidebar-toggle{top:64px;left:0;right:0;z-index:1010;align-items:center;width:100%;padding:12px 16px;border-bottom:1px solid #e0e0e0;background:#fff;font-weight:600;font-size:1.25rem;-webkit-user-select:none;user-select:none;box-shadow:0 2px 8px rgba(0,0,0,.02)}.sidebar-mobile-overlay,.sidebar-toggle{position:fixed;display:flex;justify-content:center}.sidebar-mobile-overlay{inset:0;width:100vw;height:100vh;z-index:2000;background:rgba(32,32,32,.93);align-items:start;animation:fadeIn .2s}@keyframes fadeIn{0%{opacity:0}to{opacity:1}}.sidebar-mobile-content{width:100vw;max-width:100vw;min-height:100vh;background:#fff;box-shadow:0 8px 40px rgba(0,0,0,.1);display:flex;flex-direction:column;padding-bottom:30px;animation:fadeInUp .3s}@keyframes fadeInUp{0%{opacity:0;transform:translateY(30px)}to{opacity:1;transform:translateY(0)}}.sidebar-mobile-header{display:flex;justify-content:space-between;align-items:center;font-size:1.25rem;font-weight:700;padding:18px 20px;border-bottom:1px solid #e0e0e0}.sidebar-mobile-close{font-size:2rem;background:none;border:none;color:var(--primary-color);cursor:pointer;margin-left:10px;line-height:1;padding:0 6px;transition:color .15s}.sidebar-mobile-close:hover{color:#222}.sidebar-mobile-content .sidebar-nav{padding:16px 12px}.sidebar-mobile-content .sidebar-nav-link{font-size:1.15rem;padding:16px 18px;border-radius:8px;margin-bottom:6px}}@media (min-width:769px){.sidebar-toggle{display:none}}:root{--primary-color:#6200ea;--secondary-color:#00c853;--background-color:#ffffff;--text-color:#333333;--header-height:70px;--accent-color:#ff4081;--gradient-bg:linear-gradient(135deg,#667eea,#764ba2)}.grammar-layout{display:flex;gap:30px;max-width:100%;margin:0 auto}.grammar-sidebar{width:300px;min-width:220px;max-width:340px;flex-shrink:0;position:sticky;top:64px;align-self:flex-start;height:calc(100vh - 64px);padding:20px 0;background:#fff;border-right:1px solid #e0e0e0;overflow-y:auto;z-index:10}.grammar-main{flex:1 1 0;min-width:0;max-width:100%;padding:0 15px}@media (max-width:768px){.grammar-layout{flex-direction:column;gap:0}.grammar-sidebar{width:100%;min-width:0;max-width:100%;position:relative;height:auto;margin-bottom:20px;border-right:none;border-bottom:1px solid #e0e0e0;padding:0}.grammar-main{padding:20px 8px}}.grammar-header h1,h1,h2,h3,h4,h5,h6{font-weight:700;color:var(--primary-color);margin-top:1.2em;margin-bottom:1em;letter-spacing:-1px;transition:color .3s}h1{font-size:2.4rem}h2{font-size:2rem}h3{font-size:1.5rem}h4{font-size:1.25rem}h5{font-size:1.1rem}h6{font-size:1rem}.section-title{color:var(--primary-color);font-size:1.2rem;font-weight:700;margin-bottom:.7em}.grammar-point{background-color:#f9f9f9;border-radius:12px;padding:25px;margin-bottom:30px;box-shadow:0 10px 20px rgba(0,0,0,.05);transition:box-shadow .3s,transform .3s}.grammar-point:hover{transform:translateY(-5px);box-shadow:0 15px 30px rgba(0,0,0,.1)}.example{background-color:#e8f5e9;border-left:4px solid var(--accent-color);padding:20px;margin:20px 0;border-radius:0 12px 12px 0;transition:background .3s,transform .3s}.example:hover{background-color:#c8e6c9;transform:scale(1.02)}@media (max-width:768px){.example,li,p{font-size:.8rem}.grammar-point{padding:0}}.alert-info{background-color:#e1f5fe;border-color:#4fc3f7;color:#01579b;border-radius:8px;transition:all .3s ease}.alert-info:hover{background-color:#b3e5fc;transform:translateY(-5px);box-shadow:0 10px 20px rgba(0,0,0,.1)}.text-justify{text-align:justify}.text-center{text-align:center}.blue-text{color:blue}.red-text{color:red}.green-text{color:green}table{width:100%;margin-bottom:1.5rem;background-color:transparent;border-collapse:separate;border-spacing:0 10px}th{text-align:left;background-color:#007bff!important;color:white!important;font-weight:600;border:1px solid #dee2e6}td,th{padding:15px}td{background-color:white;transition:all .3s ease}tr{box-shadow:0 2px 4px rgba(0,0,0,.05);transition:box-shadow .3s,transform .3s}tr:hover{transform:scale(1.02);box-shadow:0 4px 8px rgba(0,0,0,.1)}@media (max-width:768px){td,th{font-size:.7rem}.table{font-size:.8em}}.list-group-item{transition:all .3s ease;border-left:4px solid transparent}.list-group-item:hover{background-color:#e8eaf6;border-left:4px solid var(--primary-color);transform:translateX(5px)}.list-group-item.active{background-color:var(--primary-color);border-color:var(--primary-color);color:white}.section-toggle{cursor:pointer;transition:all .3s ease;padding:10px;background-color:#e9ecef;border-radius:5px;margin-bottom:10px;display:flex;justify-content:space-between;align-items:center}.section-toggle:hover{background-color:#c5cae9}.section-toggle:after{content:"\25BC";font-size:.8em;transition:transform .3s ease}.section-toggle.active:after{transform:rotate(180deg)}.section-content{display:none;padding:15px;background-color:white;border-radius:5px;box-shadow:0 2px 5px rgba(0,0,0,.1);animation:fadeIn .5s ease}.timeline-container{width:100%;max-width:900px;margin:50px auto;padding:30px;background-color:#f8f9fa;border-radius:15px;box-shadow:0 6px 12px rgba(0,0,0,.1)}.timeline-container h3{text-align:center;color:#007bff;margin-bottom:30px;font-size:24px}.timeline{position:relative;padding:30px 0;display:flex;justify-content:space-between}.timeline:before{content:"";position:absolute;width:100%;height:2px;background:#007bff;top:50%;transform:translateY(-50%)}.timeline-item{position:relative;width:18%;padding:15px 0;text-align:center}.timeline-item:before{content:"";position:absolute;width:24px;height:24px;background:#fff;border:4px solid #007bff;border-radius:50%;top:50%;left:50%;transform:translate(-50%,-50%);transition:all .3s ease}.timeline-item.active:before{background:#007bff;box-shadow:0 0 0 6px rgba(0,123,255,.3)}.timeline-date{display:block;font-size:16px;margin-top:35px;color:#333;font-weight:500}.timeline-item:after{content:attr(data-text);position:absolute;width:120%;left:50%;bottom:100%;transform:translateX(-50%);font-size:14px;color:#6c757d;opacity:1;transition:all .3s ease;white-space:nowrap}.timeline-item:hover:before{background:#007bff;transform:translate(-50%,-50%) scale(1.2)}.timeline-item:hover:after{opacity:1;bottom:calc(100% + 10px)}.timeline-item:hover .timeline-date{color:#007bff}@media (max-width:768px){.timeline{flex-direction:column;align-items:flex-start;padding:0 0 0 28px}.timeline:before{left:12px;top:0;width:2px;height:100%;background:#007bff;transform:none}.timeline-item{width:100%;margin-bottom:35px;padding:0 0 0 30px;text-align:left;position:relative}.timeline-item:last-child{margin-bottom:0}.timeline-item:before{left:-18px;top:10px;width:16px;height:16px;border-width:3px}.timeline-date{margin-top:0;margin-bottom:4px;font-size:13px}.timeline-item:after{position:static;transform:none;width:auto;display:block;font-size:13px;margin-bottom:2px;color:#666;opacity:1;white-space:normal;background:none}.timeline-container h3{font-size:1.1rem;margin-bottom:16px}}@media (max-width:576px){.timeline-container{padding:12px}.timeline-item{font-size:12px;padding-left:28px}.timeline-date{font-size:11px}.timeline-item:before{width:12px;height:12px;left:-15px;border-width:2px}}@keyframes fadeIn{0%{opacity:0;transform:translateY(-10px)}to{opacity:1;transform:translateY(0)}}@keyframes fadeInUp{0%{opacity:0;transform:translateY(20px)}to{opacity:1;transform:translateY(0)}}.fade-in-up{animation:fadeInUp .5s ease-out}.btn{transition:all .3s ease;position:relative;overflow:hidden}.btn:after{content:"";position:absolute;top:50%;left:50%;width:5px;height:5px;background:rgba(255,255,255,.5);opacity:0;border-radius:100%;transform:scale(1) translate(-50%);transform-origin:50% 50%}.btn:hover:after{animation:ripple 1s ease-out}@keyframes ripple{0%{transform:scale(0);opacity:1}20%{transform:scale(25);opacity:1}to{opacity:0;transform:scale(40)}}#back-to-top{position:fixed;bottom:30px;right:30px;display:none;background-color:var(--accent-color);color:white;border:none;border-radius:50%;width:50px;height:50px;text-align:center;font-size:24px;line-height:50px;cursor:pointer;transition:all .3s ease;box-shadow:0 2px 10px rgba(0,0,0,.2)}#back-to-top:hover{background-color:var(--primary-color);transform:translateY(-5px);box-shadow:0 4px 20px rgba(0,0,0,.3)}