:root{--primary-color: #58CC02;--primary-hover: #46A302;--primary-light: #58CC0220;--mask-green: #89E219;--secondary-color: #1CB0F6;--accent-color: #FF9600;--success-color: #58CC02;--error-color: #FF4B4B;--warning-color: #FFC800;--purple-color: #CE82FF;--deep-blue: #2B70C9;--text-primary: #4B4B4B;--text-secondary: #777777;--text-muted: #AFAFAF;--bg-color: #F7F7F7;--card-bg: #FFFFFF;--border-color: #E5E5E5;--shadow: 0 2px 4px rgba(0, 0, 0, .08);--shadow-md: 0 4px 12px rgba(0, 0, 0, .1);--shadow-lg: 0 8px 24px rgba(0, 0, 0, .12);--radius: 16px;--radius-sm: 12px;--radius-lg: 24px;--radius-full: 9999px;--safe-area-top: env(safe-area-inset-top, 0px);--safe-area-bottom: env(safe-area-inset-bottom, 0px);--safe-area-left: env(safe-area-inset-left, 0px);--safe-area-right: env(safe-area-inset-right, 0px);--touch-target-min: 44px;--touch-target-spacing: 8px;--bottom-nav-height: 60px;--transition-fast: .15s;--transition-normal: .25s;--transition-slow: .4s}[data-theme=dark]{--bg-color: #131F24;--card-bg: #1A2C35;--text-primary: #FFFFFF;--text-secondary: #AFAFAF;--text-muted: #777777;--border-color: #2A3F4A;--shadow: 0 2px 4px rgba(0, 0, 0, .3);--shadow-md: 0 4px 12px rgba(0, 0, 0, .4);--shadow-lg: 0 8px 24px rgba(0, 0, 0, .5)}*{margin:0;padding:0;box-sizing:border-box;-webkit-tap-highlight-color:transparent}html{-webkit-text-size-adjust:100%;scroll-behavior:smooth;height:100%;height:-webkit-fill-available}body{font-family:din-round,DIN Next Rounded,-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Noto Sans SC,PingFang SC,sans-serif;background-color:var(--bg-color);color:var(--text-primary);line-height:1.6;letter-spacing:.02em;min-height:100vh;min-height:100dvh;min-height:-webkit-fill-available;overscroll-behavior:none;padding-top:var(--safe-area-top);padding-left:var(--safe-area-left);padding-right:var(--safe-area-right);transition:background-color var(--transition-normal),color 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var(--transition-fast);min-height:var(--touch-target-min);display:flex;align-items:center;text-transform:uppercase;letter-spacing:.5px}.nav-link:hover,.nav-link.active{color:var(--primary-color);background:var(--primary-light)}.nav-user{display:flex;align-items:center;gap:1rem}.user-stats{font-size:.9rem;font-weight:700;color:var(--accent-color);background:linear-gradient(135deg,#ffd90026,#ff960026);padding:.5rem 1rem;border-radius:var(--radius-full);display:flex;align-items:center;gap:.5rem}.theme-toggle{width:44px;height:44px;border:none;background:var(--bg-color);border-radius:var(--radius-full);cursor:pointer;display:flex;align-items:center;justify-content:center;font-size:1.25rem;transition:all var(--transition-fast)}.theme-toggle:hover{background:var(--border-color);transform:rotate(20deg)}.theme-toggle:active{transform:scale(.95) rotate(20deg)}.mobile-nav{display:none;position:fixed;bottom:0;left:0;right:0;background:var(--card-bg);box-shadow:0 -4px 20px #0000001a;z-index:1000;padding-bottom:var(--safe-area-bottom);border-top:2px solid var(--border-color)}.mobile-nav-inner{display:flex;justify-content:space-around;align-items:center;height:var(--bottom-nav-height)}.mobile-nav-item{display:flex;flex-direction:column;align-items:center;justify-content:center;text-decoration:none;color:var(--text-secondary);min-width:60px;min-height:48px;padding:4px 12px;border-radius:var(--radius-sm);transition:all var(--transition-fast);flex:1;max-width:80px;position:relative}.mobile-nav-item:active{transform:scale(.9)}.mobile-nav-item.active{color:var(--primary-color)}.mobile-nav-item.active:after{content:"";position:absolute;top:0;left:50%;transform:translate(-50%);width:40px;height:3px;background:var(--primary-color);border-radius:0 0 3px 3px}.mobile-nav-icon{font-size:1.5rem;margin-bottom:2px;transition:transform var(--transition-fast)}.mobile-nav-item:active .mobile-nav-icon{transform:scale(1.2)}.mobile-nav-label{font-size:.7rem;font-weight:600}.main-content{flex:1;padding:2rem;max-width:1200px;margin:0 auto;width:100%}.hero{text-align:center;padding:3rem 2rem;background:linear-gradient(135deg,var(--primary-color) 0%,#4caf00 100%);border-radius:var(--radius-lg);color:#fff;margin-bottom:2rem;position:relative;overflow:hidden}.hero:before{content:"";position:absolute;top:-50%;right:-20%;width:300px;height:300px;background:#ffffff1a;border-radius:50%}.hero:after{content:"";position:absolute;bottom:-30%;left:-10%;width:200px;height:200px;background:#ffffff14;border-radius:50%}.hero h1{font-size:2.5rem;font-weight:800;margin-bottom:.75rem;position:relative;z-index:1}.hero p{font-size:1.1rem;opacity:.95;margin-bottom:2rem;position:relative;z-index:1}.hero-stats{display:flex;justify-content:center;gap:2rem;flex-wrap:wrap;position:relative;z-index:1}.stat-item{display:flex;flex-direction:column;align-items:center;background:#ffffff26;padding:1rem 1.5rem;border-radius:var(--radius);-webkit-backdrop-filter:blur(10px);backdrop-filter:blur(10px)}.stat-number{font-size:2.5rem;font-weight:800}.stat-label{font-size:.85rem;opacity:.9;font-weight:600}.categories h2{font-size:1.5rem;font-weight:800;margin-bottom:1.5rem;color:var(--text-primary)}.category-card{background:var(--card-bg);border-radius:var(--radius-lg);box-shadow:var(--shadow);margin-bottom:1.5rem;overflow:hidden;border:2px solid var(--border-color);transition:all var(--transition-normal)}.category-card:hover{border-color:var(--primary-color);box-shadow:var(--shadow-md)}.category-header{display:flex;align-items:center;padding:1.25rem 1.5rem;background:linear-gradient(to right,var(--primary-light),transparent);cursor:pointer;transition:background var(--transition-fast);min-height:var(--touch-target-min)}.category-header:active{background:linear-gradient(to right,rgba(88,204,2,.2),var(--primary-light))}.category-icon{font-size:2.5rem;margin-right:1rem;transition:transform var(--transition-normal)}.category-card:hover .category-icon{transform:scale(1.1) rotate(-5deg)}.category-info{flex:1}.category-info h3{font-size:1.25rem;font-weight:800;color:var(--text-primary)}.category-subtitle{color:var(--text-secondary);font-size:.9rem}.category-progress{background:var(--primary-light);padding:.5rem 1rem;border-radius:var(--radius-full);font-size:.85rem;font-weight:700;color:var(--primary-color)}.category-courses{display:grid;grid-template-columns:repeat(auto-fill,minmax(280px,1fr));gap:1rem;padding:0 1.5rem 1.5rem}.course-item{display:flex;align-items:center;padding:1rem 1.25rem;min-height:64px;background:var(--bg-color);border-radius:var(--radius);text-decoration:none;color:var(--text-primary);transition:all var(--transition-fast);border:2px solid 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1fr;gap:2rem;align-items:start}.quiz-sidebar{background:var(--card-bg);border-radius:var(--radius);box-shadow:var(--shadow);padding:1.5rem;position:sticky;top:80px}.course-title{font-size:1.25rem;margin-bottom:1rem;color:var(--primary-color);display:flex;align-items:center;gap:.5rem}.chapter-list{list-style:none}.chapter-item{margin-bottom:.5rem}.chapter-link{display:flex;align-items:center;justify-content:space-between;padding:.75rem 1rem;min-height:var(--touch-target-min);border-radius:var(--radius-sm);text-decoration:none;color:var(--text-secondary);transition:all .2s}.chapter-link:active{background:var(--bg-color)}.chapter-link.active{background:var(--primary-color);color:#fff}.chapter-progress{font-size:.75rem;background:#fff3;padding:.2rem .5rem;border-radius:4px}.quiz-main{background:var(--card-bg);border-radius:var(--radius);box-shadow:var(--shadow);padding:2rem}.quiz-header{display:flex;justify-content:space-between;align-items:center;margin-bottom:2rem;padding-bottom:1rem;border-bottom:1px solid var(--border-color)}.quiz-info h2{font-size:1.5rem;margin-bottom:.5rem}.quiz-meta{display:flex;gap:1rem;font-size:.9rem;color:var(--text-secondary)}.progress-bar{width:200px;height:8px;background:var(--bg-color);border-radius:4px;overflow:hidden}.progress-fill{height:100%;background:var(--primary-color);border-radius:4px;transition:width .3s}.question-card{margin-bottom:2rem}.question-number{display:inline-block;background:var(--secondary-color);color:#fff;padding:.3rem 1rem;border-radius:var(--radius-full);font-size:.85rem;font-weight:800;margin-bottom:1rem;text-transform:uppercase}.question-text{font-size:1.15rem;line-height:1.8;margin-bottom:1.5rem;color:var(--text-primary);font-weight:500}.options-list{display:flex;flex-direction:column;gap:12px}.option-item{display:flex;align-items:flex-start;padding:16px 20px;min-height:60px;background:var(--card-bg);border:3px solid var(--border-color);border-radius:var(--radius);cursor:pointer;transition:all var(--transition-fast);-webkit-user-select:none;user-select:none;position:relative;overflow:hidden}.option-item:before{content:"";position:absolute;bottom:0;left:0;right:0;height:4px;background:var(--border-color);transition:all 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.option-label:after{content:"✗"}.option-content{flex:1;display:flex;align-items:center;min-height:24px}.option-text{font-size:1rem;color:var(--text-primary);line-height:1.5;font-weight:500}.option-explanation{display:none;margin:.5rem 0 1rem 3rem;padding:.75rem 1rem;background:var(--card-bg);border-radius:var(--radius-sm);font-size:.9rem;color:var(--text-secondary);line-height:1.6;border-left:3px solid var(--border-color)}.option-explanation.show{display:block;animation:fadeIn .3s ease}.option-explanation .explanation-tag{font-weight:600;margin-right:.5rem}.option-explanation .correct-tag{color:var(--success-color)}.option-explanation .wrong-tag{color:var(--text-tertiary)}.explanation{margin-top:1.5rem;padding:1.5rem;background:linear-gradient(to right,#4f46e50d,#7c3aed0d);border-radius:var(--radius);border-left:4px solid var(--primary-color);display:none}.explanation.show{display:block;animation:slideIn .3s ease}@keyframes 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code{background:none;padding:0;color:inherit}.btn{display:inline-flex;align-items:center;justify-content:center;min-height:var(--touch-target-min);min-width:var(--touch-target-min);padding:14px 28px;border:none;border-radius:var(--radius);font-size:1rem;font-weight:800;cursor:pointer;transition:all var(--transition-fast);text-decoration:none;text-transform:uppercase;letter-spacing:1px;-webkit-user-select:none;user-select:none;position:relative;overflow:hidden}.btn:before{content:"";position:absolute;bottom:0;left:0;right:0;height:4px;background:#00000026;border-radius:0 0 var(--radius) var(--radius)}.btn:active{transform:translateY(2px)}.btn:active:before{height:2px}.btn-primary{background:var(--primary-color);color:#fff;box-shadow:0 4px #3d9c00}.btn-primary:hover{background:var(--primary-hover);filter:brightness(1.1)}.btn-primary:active{box-shadow:0 2px #3d9c00}.btn-secondary{background:var(--card-bg);color:var(--primary-color);border:2px solid var(--border-color);box-shadow:0 4px 0 var(--border-color)}.btn-secondary:hover{background:var(--bg-color);border-color:var(--primary-color)}.btn-secondary:active{box-shadow:0 2px 0 var(--border-color)}.btn-success{background:var(--success-color);color:#fff;box-shadow:0 4px #3d9c00}.btn-danger{background:var(--error-color);color:#fff;box-shadow:0 4px #cc3030}.quiz-actions{display:flex;justify-content:space-between;gap:var(--touch-target-spacing);margin-top:2rem;padding-top:1.5rem;border-top:1px solid var(--border-color)}.progress-overview{display:grid;grid-template-columns:repeat(auto-fit,minmax(200px,1fr));gap:1.5rem;margin-bottom:2rem}.progress-card{background:var(--card-bg);padding:1.5rem;border-radius:var(--radius-lg);box-shadow:var(--shadow);text-align:center;border:2px solid var(--border-color);transition:all var(--transition-normal)}.progress-card:hover{transform:translateY(-4px);box-shadow:var(--shadow-md);border-color:var(--primary-color)}.progress-card-icon{font-size:3rem;margin-bottom:.75rem}.progress-card-value{font-size:2.5rem;font-weight:800;color:var(--primary-color);line-height:1}.progress-card-label{color:var(--text-secondary);font-size:.9rem;font-weight:600;margin-top:.5rem}.achievements{display:grid;grid-template-columns:repeat(auto-fill,minmax(120px,1fr));gap:1rem;margin-top:2rem}.achievement-badge{display:flex;flex-direction:column;align-items:center;padding:1.25rem;background:var(--card-bg);border-radius:var(--radius);border:2px solid var(--border-color);text-align:center;transition:all var(--transition-normal)}.achievement-badge.unlocked{border-color:var(--xp-color);background:linear-gradient(135deg,#ffd9001a,#ff96000d)}.achievement-badge.locked{opacity:.5;filter:grayscale(1)}.achievement-icon{font-size:2.5rem;margin-bottom:.5rem}.achievement-name{font-size:.85rem;font-weight:700;color:var(--text-primary)}.footer{background:var(--card-bg);padding:1.5rem;text-align:center;color:var(--text-secondary);border-top:1px solid var(--border-color)}.loading{display:flex;align-items:center;justify-content:center;padding:3rem}.spinner{width:40px;height:40px;border:3px solid var(--border-color);border-top-color:var(--primary-color);border-radius:50%;animation:spin 1s linear infinite}@keyframes spin{to{transform:rotate(360deg)}}.toast{position:fixed;bottom:calc(var(--bottom-nav-height) + var(--safe-area-bottom) + 20px);left:50%;transform:translate(-50%) translateY(100px);background:var(--text-primary);color:#fff;padding:14px 24px;border-radius:var(--radius-full);box-shadow:var(--shadow-lg);opacity:0;transition:all var(--transition-normal);z-index:1001;max-width:calc(100vw - 32px);text-align:center;font-weight:700}.toast.show{transform:translate(-50%) translateY(0);opacity:1}.toast.success{background:var(--success-color)}.toast.error{background:var(--error-color)}@keyframes celebrate{0%,to{transform:scale(1) rotate(0)}25%{transform:scale(1.1) rotate(-5deg)}50%{transform:scale(1.15) rotate(5deg)}75%{transform:scale(1.1) rotate(-3deg)}}.celebrate{animation:celebrate .6s ease}.xp-popup{position:fixed;top:20%;left:50%;transform:translate(-50%);background:linear-gradient(135deg,var(--xp-color),var(--accent-color));color:#fff;font-size:1.5rem;font-weight:800;padding:1rem 2rem;border-radius:var(--radius);box-shadow:var(--shadow-lg);animation:xpPopup 1.5s ease forwards;z-index:2000}@keyframes xpPopup{0%{opacity:0;transform:translate(-50%) translateY(20px) scale(.8)}20%{opacity:1;transform:translate(-50%) translateY(0) scale(1.1)}40%{transform:translate(-50%) translateY(0) scale(1)}80%{opacity:1;transform:translate(-50%) translateY(0)}to{opacity:0;transform:translate(-50%) translateY(-30px)}}.streak-badge{position:fixed;top:80px;right:20px;background:linear-gradient(135deg,var(--accent-color),#ff6b00);color:#fff;padding:.75rem 1.25rem;border-radius:var(--radius);font-weight:800;font-size:1rem;box-shadow:var(--shadow-md);display:flex;align-items:center;gap:.5rem;animation:streakPulse 2s ease infinite;z-index:500}@keyframes streakPulse{0%,to{box-shadow:var(--shadow-md)}50%{box-shadow:0 0 20px #ff960080}}.mobile-chapter-drawer{display:none;position:fixed;top:0;left:0;right:0;bottom:0;z-index:999}.mobile-chapter-drawer.open{display:block}.drawer-overlay{position:absolute;top:0;left:0;right:0;bottom:0;background:#00000080;animation:fadeIn .2s ease}@keyframes fadeIn{0%{opacity:0}to{opacity:1}}.drawer-content{position:absolute;bottom:0;left:0;right:0;max-height:70vh;background:var(--card-bg);border-radius:var(--radius) var(--radius) 0 0;padding:1rem;padding-bottom:calc(1rem + var(--safe-area-bottom));animation:slideUp .3s ease;overflow-y:auto;-webkit-overflow-scrolling:touch}@keyframes slideUp{0%{transform:translateY(100%)}to{transform:translateY(0)}}.drawer-handle{width:40px;height:4px;background:var(--border-color);border-radius:2px;margin:0 auto 1rem}.drawer-title{font-size:1.1rem;font-weight:600;margin-bottom:1rem;color:var(--text-primary)}.drawer-chapter-list{list-style:none}.drawer-chapter-item{display:flex;align-items:center;justify-content:space-between;padding:14px 16px;min-height:48px;border-radius:var(--radius-sm);color:var(--text-secondary);text-decoration:none;margin-bottom:4px;transition:all .2s}.drawer-chapter-item:active{background:var(--bg-color)}.drawer-chapter-item.active{background:var(--primary-color);color:#fff}.icon{display:inline-flex;align-items:center;justify-content:center;flex-shrink:0}.icon svg{width:100%;height:100%}.icon-sm{width:16px;height:16px}.icon-md{width:24px;height:24px}.icon-lg{width:32px;height:32px}.icon-xl{width:48px;height:48px}.icon-primary{color:var(--primary-color)}.icon-secondary{color:var(--secondary-color)}.icon-accent{color:var(--accent-color)}.icon-success{color:var(--success-color)}.icon-error{color:var(--error-color)}.icon-warning{color:var(--warning-color)}.icon-muted{color:var(--text-secondary)}.nav-icon{width:20px;height:20px;margin-right:6px}.mobile-nav-icon .icon{width:28px;height:28px;color:inherit}.course-icon .icon,.course-icon-svg{width:32px;height:32px;color:var(--text-secondary);transition:color var(--transition-fast),transform var(--transition-fast)}.course-item:hover .course-icon .icon,.course-item:hover 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