:root{--primary: #39E079;--primary-dark: #2bc062;--primary-light: rgba(57, 224, 121, .15);--background-light: #f6f8f7;--background-dark: #122017;--text-light: #1e293b;--text-dark: #f1f5f9;--text-muted-light: #64748b;--text-muted-dark: #94a3b8;--surface-light: #ffffff;--surface-dark: #1e293b;--border-light: #e2e8f0;--border-dark: rgba(71, 85, 105, .5);--success: #22c55e;--success-bg: rgba(34, 197, 94, .1);--error: #ef4444;--error-bg: rgba(239, 68, 68, .1);--warning: #f59e0b;--warning-bg: rgba(245, 158, 11, .1);--info: #3b82f6;--info-bg: rgba(59, 130, 246, .1);--font-display: "Spline Sans", system-ui, sans-serif;--font-sans: "Inter", system-ui, sans-serif;--spacing-xs: .25rem;--spacing-sm: .5rem;--spacing-md: 1rem;--spacing-lg: 1.5rem;--spacing-xl: 2rem;--spacing-2xl: 3rem;--radius-sm: .5rem;--radius-md: 1rem;--radius-lg: 1.5rem;--radius-xl: 2rem;--radius-full: 9999px;--shadow-sm: 0 1px 2px rgba(0, 0, 0, .05);--shadow-md: 0 4px 6px rgba(0, 0, 0, .07);--shadow-lg: 0 10px 15px rgba(0, 0, 0, .1);--shadow-glow: 0 0 20px rgba(57, 224, 121, .25);--transition-fast: .15s ease;--transition-normal: .2s ease;--transition-slow: .3s ease}.dark{--background: var(--background-dark);--text: var(--text-dark);--text-muted: var(--text-muted-dark);--surface: var(--surface-dark);--border: var(--border-dark)}:root{--background: var(--background-light);--text: var(--text-light);--text-muted: var(--text-muted-light);--surface: var(--surface-light);--border: var(--border-light)}*,*:before,*:after{box-sizing:border-box;margin:0;padding:0}html{font-size:16px;-webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale}body{font-family:var(--font-display);background-color:var(--background);color:var(--text);min-height:100vh;line-height:1.5;transition:background-color var(--transition-normal),color var(--transition-normal)}::-webkit-scrollbar{width:6px}::-webkit-scrollbar-track{background:transparent}::-webkit-scrollbar-thumb{background-color:#94a3b880;border-radius:20px}h1,h2,h3,h4,h5,h6{font-family:var(--font-display);font-weight:700;line-height:1.2}h1{font-size:2.5rem}h2{font-size:2rem}h3{font-size:1.5rem}h4{font-size:1.25rem}h5{font-size:1rem}h6{font-size:.875rem}p{line-height:1.6}a{color:var(--primary);text-decoration:none;transition:color var(--transition-fast)}a:hover{color:var(--primary-dark)}.btn{display:inline-flex;align-items:center;justify-content:center;gap:var(--spacing-sm);padding:var(--spacing-sm) var(--spacing-lg);font-family:var(--font-sans);font-size:.875rem;font-weight:600;border-radius:var(--radius-md);border:none;cursor:pointer;transition:all var(--transition-normal)}.btn-primary{background:var(--primary);color:#fff;box-shadow:0 4px 12px #39e07940}.btn-primary:hover{background:var(--primary-dark);transform:translateY(-1px)}.btn-secondary{background:var(--surface);color:var(--text);border:1px solid var(--border)}.btn-secondary:hover{background:var(--border)}.btn-ghost{background:transparent;color:var(--text-muted)}.btn-ghost:hover{background:var(--primary-light);color:var(--primary)}.btn-icon{width:40px;height:40px;padding:0;border-radius:var(--radius-full)}.card{background:var(--surface);border-radius:var(--radius-lg);border:1px solid var(--border);padding:var(--spacing-lg);box-shadow:var(--shadow-sm);transition:all var(--transition-normal)}.card:hover{box-shadow:var(--shadow-md)}.card-interactive{cursor:pointer}.card-interactive:hover{transform:translateY(-2px);box-shadow:var(--shadow-lg)}.input{width:100%;padding:var(--spacing-sm) var(--spacing-md);font-family:var(--font-sans);font-size:1rem;background:var(--surface);border:1px solid var(--border);border-radius:var(--radius-md);color:var(--text);transition:all var(--transition-fast)}.input:focus{outline:none;border-color:var(--primary);box-shadow:0 0 0 3px var(--primary-light)}.input::placeholder{color:var(--text-muted)}.badge{display:inline-flex;align-items:center;gap:var(--spacing-xs);padding:.125rem .5rem;font-family:var(--font-sans);font-size:.625rem;font-weight:700;text-transform:uppercase;letter-spacing:.05em;border-radius:var(--radius-sm);border:1px solid}.badge-primary{background:var(--primary-light);color:var(--primary);border-color:#39e07933}.badge-warning{background:var(--warning-bg);color:var(--warning);border-color:#f59e0b33}.badge-success{background:var(--success-bg);color:var(--success);border-color:#22c55e33}.badge-error{background:var(--error-bg);color:var(--error);border-color:#ef444433}.highlight-word{text-decoration-line:underline;text-decoration-style:solid;text-decoration-color:var(--primary);text-decoration-thickness:2px;text-underline-offset:4px;color:var(--primary);cursor:pointer;transition:all var(--transition-normal)}.highlight-word:hover,.highlight-word.active{background-color:var(--primary-light);border-radius:4px}.quiz-option{width:100%;text-align:left;padding:var(--spacing-md);font-family:var(--font-sans);font-size:.875rem;background:var(--surface);border:1px solid var(--border);border-radius:var(--radius-md);color:var(--text);cursor:pointer;transition:all var(--transition-normal)}.quiz-option:hover{background:var(--primary-light);border-color:var(--primary)}.quiz-option.correct{background:var(--success-bg);border-color:var(--success);border-width:2px;color:var(--success)}.quiz-option.incorrect{background:var(--error-bg);border-color:var(--error);border-width:2px;color:var(--error)}.progress-dots{display:flex;gap:var(--spacing-xs)}.progress-dot{width:6px;height:6px;border-radius:var(--radius-full);background:var(--border);transition:background var(--transition-fast)}.progress-dot.active{background:var(--primary)}.progress-dot.completed{background:var(--success)}.container{max-width:768px;margin:0 auto;padding:0 var(--spacing-lg)}.page{min-height:100vh;padding-bottom:100px}.bottom-bar{position:fixed;bottom:0;left:0;right:0;background:var(--background);border-top:1px solid var(--border);padding:var(--spacing-md) var(--spacing-lg);padding-bottom:calc(var(--spacing-md) + env(safe-area-inset-bottom,0));z-index:40}.bottom-bar .container{display:flex;gap:var(--spacing-sm)}.nav{display:flex;gap:var(--spacing-xs);padding:var(--spacing-sm);background:var(--surface);border-radius:var(--radius-full);box-shadow:var(--shadow-md)}.nav-item{display:flex;flex-direction:column;align-items:center;gap:2px;padding:var(--spacing-sm) var(--spacing-md);font-family:var(--font-sans);font-size:.75rem;color:var(--text-muted);border-radius:var(--radius-lg);transition:all var(--transition-fast);text-decoration:none}.nav-item:hover,.nav-item.active{color:var(--primary);background:var(--primary-light)}.nav-item .icon{font-size:1.25rem}.tooltip{position:absolute;bottom:100%;left:50%;transform:translate(-50%);margin-bottom:8px;padding:var(--spacing-sm) var(--spacing-md);background:var(--surface-dark);color:var(--text-dark);border-radius:var(--radius-md);box-shadow:var(--shadow-lg);border:1px solid var(--border-dark);z-index:50;white-space:nowrap}.tooltip:after{content:"";position:absolute;top:100%;left:50%;margin-left:-8px;border-width:8px;border-style:solid;border-color:var(--surface-dark) transparent transparent transparent}.flashcard{perspective:1000px;width:100%;max-width:400px;height:280px;margin:0 auto}.flashcard-inner{position:relative;width:100%;height:100%;transition:transform .6s;transform-style:preserve-3d}.flashcard.flipped .flashcard-inner{transform:rotateY(180deg)}.flashcard-face{position:absolute;width:100%;height:100%;backface-visibility:hidden;display:flex;flex-direction:column;align-items:center;justify-content:center;padding:var(--spacing-xl);background:var(--surface);border-radius:var(--radius-xl);border:1px solid var(--border);box-shadow:var(--shadow-lg)}.flashcard-back{transform:rotateY(180deg);background:var(--primary-light)}.flashcard-word{font-size:2rem;font-weight:700;text-align:center;margin-bottom:var(--spacing-md)}.flashcard-hint{font-size:.875rem;color:var(--text-muted);font-family:var(--font-sans)}.spinner{width:40px;height:40px;border:3px solid var(--border);border-top-color:var(--primary);border-radius:50%;animation:spin 1s linear infinite}@keyframes spin{to{transform:rotate(360deg)}}.empty-state{text-align:center;padding:var(--spacing-2xl);color:var(--text-muted)}.empty-state .icon{font-size:3rem;margin-bottom:var(--spacing-md);opacity:.5}.text-center{text-align:center}.text-muted{color:var(--text-muted)}.text-primary{color:var(--primary)}.text-success{color:var(--success)}.text-error{color:var(--error)}.mt-sm{margin-top:var(--spacing-sm)}.mt-md{margin-top:var(--spacing-md)}.mt-lg{margin-top:var(--spacing-lg)}.mt-xl{margin-top:var(--spacing-xl)}.mb-sm{margin-bottom:var(--spacing-sm)}.mb-md{margin-bottom:var(--spacing-md)}.mb-lg{margin-bottom:var(--spacing-lg)}.mb-xl{margin-bottom:var(--spacing-xl)}.flex{display:flex}.flex-col{flex-direction:column}.items-center{align-items:center}.justify-center{justify-content:center}.justify-between{justify-content:space-between}.gap-sm{gap:var(--spacing-sm)}.gap-md{gap:var(--spacing-md)}.gap-lg{gap:var(--spacing-lg)}.grid{display:grid}.grid-cols-2{grid-template-columns:repeat(2,1fr)}.grid-cols-3{grid-template-columns:repeat(3,1fr)}.w-full{width:100%}.h-full{height:100%}@keyframes fadeIn{0%{opacity:0}to{opacity:1}}@keyframes slideUp{0%{opacity:0;transform:translateY(20px)}to{opacity:1;transform:translateY(0)}}.animate-fade-in{animation:fadeIn .3s ease}.animate-slide-up{animation:slideUp .3s ease}