@import"https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700;800;900&family=DM+Sans:opsz,wght@9..40,400;9..40,500;9..40,600;9..40,700&family=JetBrains+Mono:wght@400;600&display=swap";:root{--font-sans: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;--font-mono: "JetBrains Mono", monospace;--safe-top: env(safe-area-inset-top, 0px);--safe-bottom: env(safe-area-inset-bottom, 0px);--safe-left: env(safe-area-inset-left, 0px);--safe-right: env(safe-area-inset-right, 0px);--bg-base: #f3f6fc;--bg-primary: #f3f6fc;--bg-secondary: #ffffff;--bg-card: #ffffff;--bg-card-hover: #f8faff;--bg-glass: rgba(255, 255, 255, .88);--bg-overlay: rgba(15, 23, 42, .48);--border-color: #e5e9f2;--border-muted: #eef1f8;--border-active: #4f6ef7;--text-primary: #111827;--text-secondary: #4b5563;--text-muted: #9ca3af;--text-inverse: #ffffff;--brand: #4f6ef7;--brand-dark: #3b55d9;--brand-light: #eef2ff;--brand-glow: rgba(79, 110, 247, .18);--accent-primary: #4f6ef7;--accent-primary-hover: #3b55d9;--accent-gradient: linear-gradient(135deg, #3b55d9 0%, #4f6ef7 55%, #6b8afb 100%);--accent-gradient-warm: linear-gradient(135deg, #f59e0b 0%, #ea580c 100%);--accent-gradient-teal: linear-gradient(135deg, #0d9488 0%, #14b8a6 100%);--success: #16a34a;--success-bg: rgba(22, 163, 74, .08);--danger: #dc2626;--danger-bg: rgba(220, 38, 38, .08);--warning: #d97706;--warning-bg: rgba(217, 119, 6, .08);--info: #4f6ef7;--shadow-xs: 0 1px 2px rgba(15, 23, 42, .04);--shadow-sm: 0 1px 4px rgba(15, 23, 42, .06), 0 2px 8px rgba(15, 23, 42, .03);--shadow-md: 0 4px 16px rgba(15, 23, 42, .08), 0 2px 6px rgba(15, 23, 42, .04);--shadow-lg: 0 10px 28px rgba(15, 23, 42, .1), 0 4px 10px rgba(15, 23, 42, .05);--shadow-glow: 0 0 22px rgba(79, 110, 247, .2);--shadow-brand: 0 4px 16px rgba(79, 110, 247, .28);--radius-xs: 6px;--radius-sm: 9px;--radius-md: 13px;--radius-lg: 18px;--radius-xl: 24px;--radius-full: 9999px;--sidebar-width: 250px;--header-height: 58px}.dark{--bg-base: #0a0f1c;--bg-primary: #0a0f1c;--bg-secondary: #0f1626;--bg-card: #161f33;--bg-card-hover: #1b2540;--bg-glass: rgba(10, 15, 28, .88);--bg-overlay: rgba(0, 0, 0, .65);--border-color: rgba(255, 255, 255, .08);--border-muted: rgba(255, 255, 255, .04);--border-active: rgba(99, 132, 251, .5);--text-primary: #f1f5f9;--text-secondary: #94a3b8;--text-muted: #4b5675;--brand: #6384fb;--brand-dark: #4f6ef7;--brand-light: rgba(79, 110, 247, .14);--brand-glow: rgba(99, 132, 251, .25);--accent-primary: #6384fb;--accent-primary-hover: #7a9afc;--accent-gradient: linear-gradient(135deg, #4f6ef7 0%, #6384fb 60%, #8ba3fd 100%);--success: #22c55e;--success-bg: rgba(34, 197, 94, .1);--danger: #f87171;--danger-bg: rgba(248, 113, 113, .1);--warning: #fbbf24;--warning-bg: rgba(251, 191, 36, .1);--shadow-xs: 0 1px 3px rgba(0,0,0,.3);--shadow-sm: 0 2px 8px rgba(0,0,0,.38);--shadow-md: 0 6px 20px rgba(0,0,0,.46);--shadow-lg: 0 12px 36px rgba(0,0,0,.56);--shadow-glow: 0 0 22px rgba(99, 132, 251, .25);--shadow-brand: 0 4px 20px rgba(99, 132, 251, .32)}*,*:before,*:after{box-sizing:border-box;margin:0;padding:0;-webkit-tap-highlight-color:transparent}html{scroll-behavior:smooth;font-size:15px;overflow-x:hidden;width:100%;max-width:100vw}body{font-family:var(--font-sans);background-color:var(--bg-base);color:var(--text-primary);min-height:100vh;min-height:-webkit-fill-available;overflow-x:hidden;width:100%;max-width:100vw;line-height:1.55;-webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale;font-feature-settings:"cv02","cv03","cv11";transition:background-color .25s ease,color .25s ease}input[type=text],input[type=password],input[type=number],input[type=datetime-local],input[type=search],input[type=email],input[type=tel],select,textarea{width:100%;min-height:42px;padding:10px 14px;font-family:var(--font-sans);font-size:15px;line-height:1.45;color:var(--text-primary);background-color:var(--bg-card);border:1.5px solid var(--border-color);border-radius:var(--radius-md);outline:none;transition:all .18s ease;box-shadow:var(--shadow-xs)}@media (max-width: 768px){input[type=text],input[type=password],input[type=number],input[type=datetime-local],input[type=search],input[type=email],input[type=tel],select,textarea{font-size:16px!important;min-height:44px}}input:focus,select:focus,textarea:focus{border-color:var(--brand);box-shadow:0 0 0 3px var(--brand-glow);background-color:var(--bg-card)}input::placeholder,textarea::placeholder{color:var(--text-muted);opacity:.85}select{cursor:pointer}textarea{resize:vertical;min-height:90px}::-webkit-scrollbar{width:5px;height:5px}::-webkit-scrollbar-track{background:transparent}::-webkit-scrollbar-thumb{background:var(--border-color);border-radius:var(--radius-full)}::-webkit-scrollbar-thumb:hover{background:var(--text-muted)}.horizontal-scroll{display:flex;gap:8px;overflow-x:auto;overflow-y:hidden;-webkit-overflow-scrolling:touch;scrollbar-width:thin;padding-bottom:6px;max-width:100%}.app-container{display:flex;min-height:100vh;width:100%;background:var(--bg-base);position:relative;overflow-x:hidden}.sidebar{width:var(--sidebar-width);background:var(--bg-secondary);border-right:1px solid var(--border-color);display:flex;flex-direction:column;flex-shrink:0;position:sticky;top:0;height:100vh;z-index:40}.main-content{flex:1;display:flex;flex-direction:column;min-width:0;padding-bottom:calc(72px + var(--safe-bottom));padding-left:var(--safe-left);padding-right:var(--safe-right);overflow-x:hidden}@media (min-width: 769px){.main-content{padding-bottom:28px}}.mobile-nav{display:none;position:fixed;bottom:0;left:0;right:0;height:calc(56px + var(--safe-bottom));padding-bottom:var(--safe-bottom);padding-left:var(--safe-left);padding-right:var(--safe-right);background:var(--bg-glass);backdrop-filter:blur(24px) saturate(1.8);-webkit-backdrop-filter:blur(24px) saturate(1.8);border-top:1px solid var(--border-color);z-index:90;justify-content:space-around;align-items:center;box-shadow:0 -4px 20px #0000000f}@media (max-width: 768px){.sidebar{display:none!important}.mobile-nav{display:flex!important}}.app-header{position:sticky;top:0;z-index:30;height:calc(var(--header-height) + var(--safe-top));padding-top:var(--safe-top);padding-left:max(14px,var(--safe-left));padding-right:max(14px,var(--safe-right));background:var(--bg-glass);backdrop-filter:blur(20px) saturate(1.6);-webkit-backdrop-filter:blur(20px) saturate(1.6);border-bottom:1px solid var(--border-muted);display:flex;align-items:center;justify-content:space-between;gap:10px;box-shadow:var(--shadow-xs)}.card{background:var(--bg-card);border:1px solid var(--border-color);border-radius:var(--radius-lg);box-shadow:var(--shadow-sm);transition:box-shadow .2s ease,border-color .2s ease,transform .2s ease}.card:hover{box-shadow:var(--shadow-md)}.card-interactive{cursor:pointer}.card-interactive:hover{border-color:var(--border-active);transform:translateY(-2px);box-shadow:var(--shadow-md)}@media (max-width: 480px){.card{border-radius:var(--radius-md)}}.btn{display:inline-flex;align-items:center;justify-content:center;gap:7px;padding:8px 16px;min-height:38px;font-family:var(--font-sans);font-size:.855rem;font-weight:600;letter-spacing:-.01em;border-radius:var(--radius-md);border:none;cursor:pointer;transition:all .15s ease;-webkit-user-select:none;user-select:none;white-space:nowrap;text-decoration:none}.btn:active{transform:scale(.97)}.btn-primary{background:var(--accent-gradient);color:#fff;box-shadow:var(--shadow-brand)}.btn-primary:hover{filter:brightness(1.08);transform:translateY(-1px);box-shadow:0 6px 22px #4f6ef761}.btn-secondary{background:var(--bg-card);color:var(--text-secondary);border:1px solid var(--border-color);box-shadow:var(--shadow-xs)}.btn-secondary:hover{background:var(--bg-card-hover);color:var(--text-primary);border-color:var(--text-muted)}.btn-success{background:var(--accent-gradient-teal);color:#fff;box-shadow:0 4px 14px #0d948847}.btn-success:hover{filter:brightness(1.07);transform:translateY(-1px)}.btn-ghost{background:transparent;color:var(--text-secondary);border:none;box-shadow:none}.btn-ghost:hover{background:var(--bg-card-hover);color:var(--text-primary)}.btn-icon{width:34px;height:34px;min-height:34px;padding:0;border-radius:var(--radius-md);flex-shrink:0;display:inline-flex;align-items:center;justify-content:center}.btn-icon-round{width:34px;height:34px;min-height:34px;padding:0;border-radius:var(--radius-full);flex-shrink:0;display:inline-flex;align-items:center;justify-content:center}.badge{display:inline-flex;align-items:center;gap:4px;padding:3px 8px;font-size:.7rem;font-weight:700;letter-spacing:.01em;border-radius:var(--radius-full);line-height:1.4}.flashcard-wrapper{perspective:1200px;width:100%;max-width:520px;min-height:280px;margin:0 auto}.flashcard-inner{position:relative;width:100%;min-height:280px;text-align:center;transition:transform .55s cubic-bezier(.4,0,.2,1);transform-style:preserve-3d;cursor:pointer}.flashcard-inner.flipped{transform:rotateY(180deg)}.flashcard-front,.flashcard-back{position:absolute;width:100%;height:100%;-webkit-backface-visibility:hidden;backface-visibility:hidden;border-radius:var(--radius-xl);padding:24px 18px;display:flex;flex-direction:column;justify-content:space-between;border:1px solid var(--border-color);box-shadow:var(--shadow-lg)}.flashcard-front{background:var(--bg-card)}.flashcard-back{background:linear-gradient(145deg,#1e3a8a,#162d6e);color:#fff;transform:rotateY(180deg);border-color:#6384fb4d}.option-item{display:flex;align-items:center;gap:12px;padding:12px 15px;min-height:48px;border-radius:var(--radius-md);background:var(--bg-card);border:1.5px solid var(--border-color);cursor:pointer;transition:all .15s ease;-webkit-user-select:none;user-select:none}.option-item:hover{background:var(--bg-card-hover);border-color:var(--brand);transform:translate(2px)}.option-item.selected{background:var(--brand-light);border-color:var(--brand);box-shadow:0 0 0 3px var(--brand-glow)}.dark .option-item.selected{background:#6384fb24}.option-item.correct{background:var(--success-bg);border-color:var(--success);color:var(--success)}.option-item.incorrect{background:var(--danger-bg);border-color:var(--danger);color:var(--danger)}.code-box{font-family:var(--font-mono);background:#0f172a;border:1px solid rgba(255,255,255,.08);border-radius:var(--radius-md);padding:13px 15px;font-size:.83rem;color:#7dd3fc;overflow-x:auto;line-height:1.65}@keyframes slideUp{0%{opacity:0;transform:translateY(12px)}to{opacity:1;transform:translateY(0)}}@keyframes fadeIn{0%{opacity:0}to{opacity:1}}@keyframes pulseGlow{0%,to{box-shadow:0 0 10px var(--brand-glow)}50%{box-shadow:0 0 24px #4f6ef761}}.animate-slide-up{animation:slideUp .26s cubic-bezier(.16,1,.3,1) forwards}.animate-fade-in{animation:fadeIn .2s ease forwards}.desktop-inline{display:none!important}@media (min-width: 769px){.desktop-inline{display:inline!important}}.text-gradient{background:var(--accent-gradient);-webkit-background-clip:text;-webkit-text-fill-color:transparent;background-clip:text}h1,h2,h3,h4,h5,h6{font-family:var(--font-sans);font-weight:700;line-height:1.3;letter-spacing:-.02em;color:var(--text-primary)}