:root{--brutal-black: #0D0D0D;--brutal-paper: #FAFAF7;--brutal-card-bg: #FFFFFF;--brutal-yellow: #F5C518;--brutal-yellow-hover: #E5B508;--brutal-green: #16A34A;--brutal-red: #DC2626;--brutal-purple: #9333EA;--brutal-blue: #2563EB;--brutal-orange: #EA580C;--brutal-sky: #0284C7;--brutal-muted: #6B7280;--brutal-border: #0D0D0D}.brutal-root{background-color:var(--brutal-paper);color:var(--brutal-black);min-height:calc(100vh - 70px);padding-bottom:4rem;max-width:100%;box-sizing:border-box}.border-brutal-2{border:2px solid var(--brutal-border)}.border-brutal-3{border:3px solid var(--brutal-border)}.border-brutal-4{border:4px solid var(--brutal-border)}.shadow-brutal-sm{box-shadow:2px 2px 0 var(--brutal-border)}.shadow-brutal{box-shadow:3px 3px 0 var(--brutal-border)}.shadow-brutal-lg{box-shadow:5px 5px 0 var(--brutal-border)}.shadow-brutal-xl{box-shadow:6px 6px 0 var(--brutal-border)}.brutal-card-hover{transition:transform .15s ease,box-shadow .15s ease}.brutal-card-hover:hover{transform:translate(-2px,-2px);box-shadow:5px 5px 0 var(--brutal-border)}.btn-brutal-primary{background-color:var(--brutal-yellow);color:var(--brutal-black);border:2px solid var(--brutal-border);box-shadow:3px 3px 0 var(--brutal-border);font-weight:700;padding:.6rem 1.25rem;border-radius:4px;cursor:pointer;display:inline-flex;align-items:center;gap:.5rem;transition:all .15s ease;font-size:.95rem}.btn-brutal-primary:hover{background-color:var(--brutal-yellow-hover);transform:translate(-1px,-1px);box-shadow:4px 4px 0 var(--brutal-border)}.btn-brutal-primary:active{transform:translate(2px,2px);box-shadow:1px 1px 0 var(--brutal-border)}.btn-brutal-secondary{background-color:#fff;color:var(--brutal-black);border:2px solid var(--brutal-border);box-shadow:3px 3px 0 var(--brutal-border);font-weight:700;padding:.6rem 1.25rem;border-radius:4px;cursor:pointer;display:inline-flex;align-items:center;gap:.5rem;transition:all .15s ease;font-size:.95rem}.btn-brutal-secondary:hover{background-color:#f4f4f5;transform:translate(-1px,-1px);box-shadow:4px 4px 0 var(--brutal-border)}.btn-brutal-secondary:active{transform:translate(2px,2px);box-shadow:1px 1px 0 var(--brutal-border)}.badge-brutal{display:inline-flex;align-items:center;gap:.35rem;padding:.25rem .65rem;border:2px solid var(--brutal-border);border-radius:9999px;font-weight:800;font-size:.75rem;text-transform:uppercase;letter-spacing:.05em;box-shadow:1px 1px 0 var(--brutal-border)}.brutal-tabs-bar{display:flex;flex-wrap:wrap;border:2px solid var(--brutal-border);background:#fff;box-shadow:3px 3px 0 var(--brutal-border);border-radius:6px;overflow:hidden;margin-bottom:1.5rem}.brutal-tab-item{padding:.75rem 1.25rem;font-weight:800;font-size:.9rem;border:none;background:transparent;color:var(--brutal-black);cursor:pointer;border-right:2px solid var(--brutal-border);display:flex;align-items:center;gap:.4rem;transition:background-color .15s ease}.brutal-tab-item:last-child{border-right:none}.brutal-tab-item.active{background-color:var(--brutal-yellow)}.brutal-tab-item:hover:not(.active){background-color:#f4f4f5}@media(max-width:768px){.brutal-tab-item{padding:.5rem .75rem;font-size:.8rem}}:root{--flipbook-perspective: 1000px;--flipbook-duration: .5s;--flipbook-easing: cubic-bezier(.4, 0, .2, 1);--flipbook-border: #0D0D0D;--flipbook-yellow: #F5C518;--flipbook-yellow-hover: #E5B508;--flipbook-dark-face: #0F172A;--flipbook-paper: #FAFAF7}.flipbook-container{display:flex;flex-direction:column;gap:1.25rem;width:100%;position:relative;box-sizing:border-box}@media(min-width:1024px){.flipbook-container{flex-direction:row;gap:0;align-items:stretch;min-height:540px;border:3px solid var(--flipbook-border);border-radius:8px;background-color:#fff;box-shadow:5px 5px 0 var(--flipbook-border);overflow:hidden}}.flipbook-panel-left{width:100%;background-color:var(--flipbook-paper);display:flex;flex-direction:column;box-sizing:border-box;padding:1rem}@media(min-width:1024px){.flipbook-panel-left{width:var(--left-panel-width, 300px);min-width:200px;max-width:450px;border-right:2px solid var(--flipbook-border);flex-shrink:0}}.flipbook-panel-right{width:100%;background-color:var(--flipbook-paper);display:flex;flex-direction:column;box-sizing:border-box;padding:1rem}@media(min-width:1024px){.flipbook-panel-right{width:var(--right-panel-width, 300px);min-width:200px;max-width:450px;border-left:2px solid var(--flipbook-border);flex-shrink:0}}.flipbook-resizer{display:none}@media(min-width:1024px){.flipbook-resizer{display:flex;width:6px;cursor:col-resize;background-color:#e5e7eb;transition:background-color .15s ease;-webkit-user-select:none;user-select:none;align-items:center;justify-content:center;z-index:10;flex-shrink:0}.flipbook-resizer:hover,.flipbook-resizer.is-active{background-color:#2563eb}.flipbook-resizer:after{content:"";width:2px;height:32px;background-color:#9ca3af;border-radius:1px}}.flipbook-stage-center{flex:1 1 0%;min-width:0;background-color:#fff;padding:1.5rem;display:flex;flex-direction:column;justify-content:space-between;align-items:center;position:relative}.flipbook-scene{perspective:1000px;-webkit-perspective:1000px;width:100%;max-width:440px;height:270px;cursor:pointer;-webkit-user-select:none;user-select:none;margin:auto 0}.flipbook-card-inner{width:100%;height:100%;position:relative;transform-style:preserve-3d;-webkit-transform-style:preserve-3d;transition:transform var(--flipbook-duration) var(--flipbook-easing);border-radius:10px}.flipbook-card-inner.is-flipped{transform:rotateY(180deg)}.flipbook-face{position:absolute;top:0;right:0;bottom:0;left:0;border-radius:10px;backface-visibility:hidden;-webkit-backface-visibility:hidden;display:flex;flex-direction:column;justify-content:space-between;box-sizing:border-box}.flipbook-face-front{background-color:#fff;border:4px solid var(--flipbook-border);box-shadow:4px 4px 0 var(--flipbook-border);padding:1.25rem;align-items:center;text-align:center}.flipbook-thumb-container{width:80px;height:80px;border:2px solid var(--flipbook-border);border-radius:8px;box-shadow:2px 2px 0 var(--flipbook-border);overflow:hidden;position:relative;margin-bottom:.5rem;flex-shrink:0;background-color:#f3f4f6}.flipbook-thumb-img{width:100%;height:100%;object-fit:cover;transition:opacity .3s ease}.flipbook-word-heading{font-size:1.5rem;font-weight:900;text-transform:uppercase;color:var(--flipbook-border);letter-spacing:-.02em;margin:.2rem 0;line-height:1.2}.flipbook-ipa-badge{font-family:ui-monospace,SFMono-Regular,Menlo,Monaco,Consolas,monospace;font-size:.85rem;font-weight:700;color:#1e40af;background-color:#eff6ff;border:1px solid #BFDBFE;padding:.15rem .6rem;border-radius:4px;display:inline-block}.flipbook-flip-hint{font-family:ui-monospace,SFMono-Regular,Menlo,Monaco,Consolas,monospace;font-size:.68rem;font-weight:700;color:#9ca3af;text-transform:uppercase;border-top:1px dashed #E5E7EB;width:100%;padding-top:.4rem;letter-spacing:.05em}.flipbook-face-back{background-color:var(--flipbook-dark-face);color:#fff;border:4px solid var(--flipbook-border);box-shadow:4px 4px 0 var(--flipbook-border);transform:rotateY(180deg);padding:1.25rem}.flipbook-back-scroll{overflow-y:auto;max-height:180px;padding-right:.35rem;display:flex;flex-direction:column;gap:.65rem}.flipbook-meaning-text{font-size:1.05rem;font-weight:800;color:#f8fafc;margin:0;line-height:1.4}.flipbook-example-box{font-size:.82rem;font-style:italic;color:#cbd5e1;border-left:2px solid #60A5FA;padding-left:.6rem;margin:0;line-height:1.45}.flipbook-collocations-wrap{display:flex;flex-wrap:wrap;gap:.35rem}.flipbook-collocation-pill{display:inline-flex;align-items:center;font-size:.72rem;font-weight:600;color:#e2e8f0;background-color:#ffffff1f;border:1px solid rgba(255,255,255,.2);padding:.15rem .5rem;border-radius:4px;line-height:1.2}.book-spine-shadow{position:absolute;top:0;bottom:0;left:50%;width:32px;transform:translate(-50%);background:linear-gradient(to right,#0003,#00000014 35%,#00000005,#00000014 65%,#0003);pointer-events:none;z-index:5}.flipbook-progress-track{height:12px;width:100%;background-color:#e5e7eb;border:2px solid var(--flipbook-border);border-radius:9999px;overflow:hidden;padding:1px}.flipbook-progress-fill{height:100%;background-color:#16a34a;border-radius:9999px;transition:width .3s ease}.flipbook-scroll::-webkit-scrollbar{width:4px}.flipbook-scroll::-webkit-scrollbar-track{background:transparent}.flipbook-scroll::-webkit-scrollbar-thumb{background:#cbd5e1;border-radius:2px}:root{--fb-perspective: 2000px;--fb-spine-width: 44px;--fb-gold: #fbbf24;--fb-gold-hover: #f59e0b;--fb-gold-dark: #b45309;--fb-gold-bg: rgba(254, 243, 199, .4);--fb-dark-900: #0f172a;--fb-dark-800: #1e293b;--fb-dark-700: #334155;--fb-border-dark: #1e293b;--fb-paper-left: #ffffff;--fb-paper-right: #fffdfa;--fb-border-light: #e2e8f0;--fb-text-dark: #0f172a;--fb-text-muted: #64748b;--fb-text-subtle: #94a3b8;--fb-blue: #2563eb;--fb-blue-hover: #1d4ed8;--fb-blue-bg: #eff6ff;--fb-shadow-book: 0 25px 50px -12px rgba(0, 0, 0, .25), 0 0 25px rgba(0, 0, 0, .06)}.flipbook-explorer-page,[data-testid=flipbook-explorer-page]{max-width:1280px;margin:0 auto;padding:1.5rem 1rem;display:flex;flex-direction:column;gap:1.5rem;font-family:var(--font-sans, system-ui, -apple-system, sans-serif)}@media(min-width:640px){.flipbook-explorer-page,[data-testid=flipbook-explorer-page]{padding:2rem 1.5rem}}.flipbook-hero-banner,[data-testid=flipbook-explorer-page]>div:first-child{position:relative;border-radius:24px;background:linear-gradient(135deg,#09090b,#0f172a 45%,#291505);padding:1.75rem;color:#fff;box-shadow:0 20px 25px -5px #0000004d,0 8px 10px -6px #0000004d;overflow:hidden;border:2px solid #27272a}@media(min-width:768px){.flipbook-hero-banner,[data-testid=flipbook-explorer-page]>div:first-child{padding:2.25rem 2.5rem}}.flipbook-hero-badge{display:inline-flex;align-items:center;gap:.375rem;padding:.25rem .75rem;border-radius:9999px;background-color:var(--fb-gold);color:#1c1917;font-size:.75rem;font-weight:900;text-transform:uppercase;letter-spacing:.05em;box-shadow:0 1px 3px #0003;margin-bottom:.75rem}.flipbook-hero-title{font-size:1.75rem;font-weight:900;letter-spacing:-.02em;line-height:1.2;text-transform:uppercase;color:#fff;font-family:serif;margin-bottom:.75rem}@media(min-width:768px){.flipbook-hero-title{font-size:2.25rem}}.flipbook-hero-title span{color:var(--fb-gold)}.flipbook-hero-desc{font-size:.85rem;color:#d6d3d1;font-weight:500;line-height:1.6;max-width:48rem;margin-bottom:1rem}@media(min-width:768px){.flipbook-hero-desc{font-size:.95rem}}.flipbook-hero-features{display:flex;flex-wrap:wrap;gap:1rem 1.5rem;padding-top:.25rem;font-size:.75rem;color:#fde68a;font-family:monospace}.flipbook-hero-features>div{display:flex;align-items:center;gap:.375rem}.flipbook-tabs-bar,[data-testid=flipbook-book-tabs]{background-color:var(--fb-dark-900);border:2px solid var(--fb-dark-800);padding:.75rem 1rem;border-radius:18px;box-shadow:0 10px 15px -3px #0003;display:flex;flex-wrap:wrap;gap:.75rem;align-items:center;justify-content:space-between}.flipbook-tabs-label{display:flex;align-items:center;gap:.5rem;padding:0 .5rem;color:var(--fb-gold);font-size:.75rem;font-weight:900;text-transform:uppercase;letter-spacing:.05em;white-space:nowrap}.flipbook-tabs-list{display:flex;flex-wrap:wrap;gap:.5rem}.flipbook-tab-btn,[data-testid^=tab-book-]{display:inline-flex;align-items:center;gap:.375rem;padding:.45rem .85rem;border-radius:12px;font-size:.75rem;font-weight:700;cursor:pointer;transition:all .2s cubic-bezier(.4,0,.2,1);border:1px solid var(--fb-dark-700);background-color:var(--fb-dark-800);color:#cbd5e1;text-decoration:none;white-space:nowrap}.flipbook-tab-btn:hover,[data-testid^=tab-book-]:hover{background-color:var(--fb-dark-700);color:#fff;border-color:#475569}.flipbook-tab-btn.is-active,.flipbook-tab-btn[data-active=true]{background-color:var(--fb-gold);color:#1c1917;border-color:#fcd34d;box-shadow:0 4px 8px -1px #fbbf2459;transform:translateY(-1px) scale(1.02)}.flipbook-stats-bar{background-color:#fff;border:1px solid var(--fb-border-light);padding:.75rem 1.25rem;border-radius:16px;display:flex;flex-wrap:wrap;align-items:center;justify-content:space-between;gap:.75rem;box-shadow:0 1px 3px #0000000d;font-size:.8rem}.flipbook-stats-left{display:flex;align-items:center;gap:.5rem;font-weight:700;color:var(--fb-text-dark)}.flipbook-level-badge{padding:.2rem .5rem;background-color:var(--fb-blue-bg);color:#1d4ed8;border:1px solid #bfdbfe;border-radius:6px;font-family:monospace;font-size:.7rem;font-weight:700}.flipbook-stats-right{display:flex;align-items:center;gap:.75rem;color:var(--fb-text-muted);font-family:monospace;font-size:.75rem}.flipbook-perspective-container,[data-testid=flipbook-reader]{perspective:var(--fb-perspective);width:100%;display:flex;flex-direction:column;gap:1rem}.flipbook-toolbar{background-color:var(--fb-dark-900);color:#fff;padding:.85rem 1.25rem;border-radius:18px;display:flex;flex-wrap:wrap;align-items:center;justify-content:space-between;gap:.75rem;box-shadow:0 4px 6px -1px #0000001a;border:2px solid var(--fb-dark-800)}.flipbook-toolbar-title{font-size:.85rem;font-weight:900;color:var(--fb-gold);text-transform:uppercase;letter-spacing:-.01em}.flipbook-toolbar-sub{font-size:.7rem;color:var(--fb-text-subtle);margin-top:.15rem}.flipbook-progress-pill{display:flex;align-items:center;gap:.5rem;background:#1e293bcc;padding:.25rem .75rem;border-radius:9999px;border:1px solid var(--fb-dark-700)}.flipbook-progress-track{width:4.5rem;height:6px;background-color:var(--fb-dark-700);border-radius:9999px;overflow:hidden}.flipbook-progress-bar{height:100%;background-color:var(--fb-gold);border-radius:9999px;transition:width .3s ease}.flipbook-btn-toc,[data-testid=toggle-toc-btn]{display:inline-flex;align-items:center;gap:.4rem;padding:.4rem .85rem;border-radius:12px;font-size:.75rem;font-weight:700;cursor:pointer;border:1px solid var(--fb-dark-700);background-color:var(--fb-dark-800);color:#e2e8f0;transition:all .2s ease}.flipbook-btn-toc:hover,[data-testid=toggle-toc-btn]:hover{background-color:var(--fb-dark-700);color:#fff}.flipbook-btn-toc.is-open{background-color:var(--fb-gold);color:#1c1917;border-color:#fcd34d}.flipbook-btn-nav,[data-testid=prev-spread-btn],[data-testid=next-spread-btn]{display:inline-flex;align-items:center;justify-content:center;padding:.4rem;border-radius:8px;background-color:var(--fb-dark-800);color:#fff;border:1px solid var(--fb-dark-700);cursor:pointer;transition:all .2s ease}.flipbook-btn-nav:hover:not(:disabled),[data-testid=prev-spread-btn]:hover:not(:disabled),[data-testid=next-spread-btn]:hover:not(:disabled){background-color:var(--fb-dark-700)}.flipbook-btn-nav:disabled,[data-testid=prev-spread-btn]:disabled,[data-testid=next-spread-btn]:disabled{opacity:.3;cursor:not-allowed}.flipbook-spread-indicator{font-size:.75rem;font-family:monospace;font-weight:700;color:#cbd5e1;padding:0 .35rem}.flipbook-mobile-toggle{display:flex;background-color:#e2e8f0;padding:.25rem;border-radius:12px;gap:.25rem;width:100%}@media(min-width:768px){.flipbook-mobile-toggle{display:none}}.flipbook-mobile-toggle-btn{flex:1;padding:.5rem .75rem;border-radius:8px;font-size:.75rem;font-weight:700;border:none;cursor:pointer;background:transparent;color:#475569;transition:all .2s ease;text-align:center}.flipbook-mobile-toggle-btn.is-active{background-color:#fff;color:var(--fb-text-dark);box-shadow:0 1px 3px #0000001a}.flipbook-book-container,[data-testid=book-container]{transform-style:preserve-3d;transition:transform .6s cubic-bezier(.4,0,.2,1);transform-origin:center;position:relative;background-color:#fff;border:4px solid var(--fb-dark-800);border-radius:24px;box-shadow:var(--fb-shadow-book);width:100%;max-width:1200px;margin:0 auto;overflow:hidden;-webkit-user-select:none;user-select:none;display:flex;flex-direction:column;min-height:520px}@media(min-width:768px){.flipbook-book-container,[data-testid=book-container]{flex-direction:row;height:82vh;min-height:680px;max-height:880px}}.flipbook-spine-shadow,[data-testid=spine-shadow]{position:absolute;top:0;bottom:0;left:50%;width:var(--fb-spine-width);transform:translate(-50%);background:linear-gradient(to right,transparent 0%,rgba(0,0,0,.02) 20%,rgba(0,0,0,.15) 50%,rgba(0,0,0,.02) 80%,transparent 100%);z-index:25;pointer-events:none;display:none}@media(min-width:768px){.flipbook-spine-shadow,[data-testid=spine-shadow]{display:block}}.flipping-next{animation:flipbookFlipNext .6s ease-in-out forwards}.flipping-prev{animation:flipbookFlipPrev .6s ease-in-out forwards}@keyframes flipbookFlipNext{0%{transform:rotateY(0)}50%{transform:rotateY(-8deg) scale(.97)}to{transform:rotateY(0) scale(1)}}@keyframes flipbookFlipPrev{0%{transform:rotateY(0)}50%{transform:rotateY(8deg) scale(.97)}to{transform:rotateY(0) scale(1)}}@media(prefers-reduced-motion:reduce){.flipbook-book-container,.flipping-next,.flipping-prev{animation:none!important;transition:none!important;transform:none!important}}.flipbook-left-page,[data-testid=left-page]{flex:1;padding:1.5rem;border-bottom:1px solid var(--fb-border-light);position:relative;overflow:hidden;height:100%;display:flex;flex-direction:column;background-color:var(--fb-paper-left)}@media(min-width:768px){.flipbook-left-page,[data-testid=left-page]{padding:2.25rem 2.5rem;border-bottom:none;border-right:1px solid var(--fb-border-light);box-shadow:inset -15px 0 20px -15px #0000000f}}.flipbook-cover-content{height:100%;display:flex;flex-direction:column;justify-content:center;align-items:center;text-align:center;padding:1.5rem;border:3px solid rgba(217,119,6,.2);border-radius:20px;background-color:#fef3c733}.flipbook-cover-icon{width:5rem;height:5rem;background-color:#fef3c7;border:2px solid #fde68a;border-radius:20px;display:flex;align-items:center;justify-content:center;color:var(--fb-gold-dark);margin-bottom:1.25rem;box-shadow:0 2px 6px #0000000d}.flipbook-cover-category{padding:.25rem .75rem;background-color:#fde68a;color:#78350f;font-size:.65rem;font-weight:900;text-transform:uppercase;border-radius:9999px;letter-spacing:.1em;margin-bottom:.75rem}.flipbook-cover-title{font-size:1.75rem;font-weight:900;color:var(--fb-text-dark);font-family:serif;line-height:1.25;margin-bottom:.75rem}@media(min-width:768px){.flipbook-cover-title{font-size:2.25rem}}.flipbook-cover-desc{font-size:.85rem;color:var(--fb-text-muted);font-weight:500;max-width:26rem;margin:0 auto 1.25rem;line-height:1.6}.flipbook-cover-chips{display:flex;flex-wrap:wrap;gap:.5rem;justify-content:center;margin-bottom:1.5rem}.flipbook-cover-chip{padding:.35rem .75rem;background-color:#f1f5f9;color:#334155;font-size:.75rem;font-weight:700;border-radius:8px;border:1px solid var(--fb-border-light)}.flipbook-btn-start,[data-testid=start-reading-btn]{display:inline-flex;align-items:center;gap:.5rem;padding:.75rem 1.5rem;background-color:var(--fb-gold);color:#000;font-weight:900;font-size:.8rem;text-transform:uppercase;letter-spacing:.05em;border-radius:14px;border:none;cursor:pointer;box-shadow:0 4px 8px -1px #f59e0b59;transition:all .2s cubic-bezier(.4,0,.2,1)}.flipbook-btn-start:hover,[data-testid=start-reading-btn]:hover{background-color:var(--fb-gold-hover);transform:translateY(-2px);box-shadow:0 6px 12px -2px #f59e0b73}.flipbook-questions-header{margin-bottom:1rem;border-bottom:1px solid #f1f5f9;padding-bottom:.75rem;flex-shrink:0}.flipbook-unit-badge{font-size:.65rem;font-weight:900;text-transform:uppercase;letter-spacing:.1em;color:var(--fb-blue);background-color:var(--fb-blue-bg);padding:.2rem .55rem;border-radius:9999px;border:1px solid #bfdbfe}.flipbook-unit-title{font-size:1.35rem;font-weight:900;color:var(--fb-text-dark);font-family:serif;line-height:1.25;margin-top:.35rem}.flipbook-unit-subtitle{font-size:.75rem;color:var(--fb-text-muted);font-style:italic;margin-top:.25rem}.flipbook-questions-list{flex:1;overflow-y:auto;padding-right:.35rem;display:flex;flex-direction:column;gap:.65rem}.flipbook-question-card,[data-testid^=question-item-]{padding:.85rem 1rem;border-radius:14px;border:1px solid var(--fb-border-light);background-color:#fff;cursor:pointer;display:flex;align-items:flex-start;justify-content:space-between;gap:.75rem;transition:all .2s cubic-bezier(.4,0,.2,1)}.flipbook-question-card:hover,[data-testid^=question-item-]:hover{background-color:#eff6ff80;border-color:#93c5fd}.flipbook-question-card.is-selected,.flipbook-question-card[data-selected=true]{background-color:var(--fb-blue);border-color:var(--fb-blue);color:#fff;box-shadow:0 4px 10px -2px #2563eb59}.flipbook-part-pill{font-size:.7rem;font-family:monospace;font-weight:700;padding:.15rem .4rem;border-radius:4px;background-color:#f1f5f9;color:#475569;flex-shrink:0;margin-top:.1rem}.flipbook-question-card.is-selected .flipbook-part-pill{background-color:#1d4ed8;color:#fff}.flipbook-question-prompt{font-size:.8rem;line-height:1.5;font-weight:500;color:#334155}.flipbook-question-card.is-selected .flipbook-question-prompt{color:#fff;font-weight:700}.flipbook-page-footer{padding-top:.75rem;margin-top:auto;border-top:1px solid #f1f5f9;display:flex;align-items:center;justify-content:space-between;font-size:.75rem;color:var(--fb-text-subtle);font-family:monospace}.flipbook-right-page,[data-testid=right-page]{flex:1;padding:1.5rem;background-color:var(--fb-paper-right);position:relative;overflow:hidden;height:100%;display:flex;flex-direction:column}@media(min-width:768px){.flipbook-right-page,[data-testid=right-page]{padding:2.25rem 2.5rem;box-shadow:inset 15px 0 20px -15px #0000000f}}.flipbook-toc-title{font-size:1.6rem;font-family:serif;font-weight:900;color:var(--fb-text-dark);text-align:center;margin-bottom:.25rem}.flipbook-toc-sub{font-size:.75rem;color:var(--fb-text-muted);font-style:italic;text-align:center;margin-bottom:1rem}.flipbook-toc-list{flex:1;overflow-y:auto;padding-right:.35rem;display:flex;flex-direction:column;gap:.5rem}.flipbook-toc-item,[data-testid^=toc-item-]{display:flex;align-items:center;justify-content:space-between;padding:.75rem 1rem;border-radius:12px;border:1px solid var(--fb-border-light);background-color:#fff;cursor:pointer;transition:all .2s ease}.flipbook-toc-item:hover,[data-testid^=toc-item-]:hover{border-color:var(--fb-gold);background-color:#fef3c759;transform:translate(2px)}.flipbook-master-key-header{display:flex;align-items:center;justify-content:space-between;border-bottom:1px solid var(--fb-border-light);padding-bottom:.65rem;margin-bottom:.85rem;flex-shrink:0}.flipbook-master-key-label{color:#92400e;font-weight:900;font-size:.7rem;text-transform:uppercase;letter-spacing:.05em;display:flex;align-items:center;gap:.35rem}.flipbook-audio-btn,[data-testid=audio-btn]{padding:.35rem .75rem;background-color:var(--fb-blue-bg);color:var(--fb-blue);border-radius:9999px;cursor:pointer;border:none;font-size:.75rem;font-weight:700;display:inline-flex;align-items:center;gap:.35rem;transition:all .2s ease}.flipbook-audio-btn:hover,[data-testid=audio-btn]:hover{background-color:#dbeafe;color:#1d4ed8}.speaking-timer-card,[data-testid=speaking-timer]{background-color:#f8fafc;border:1px solid var(--fb-border-light);border-radius:16px;padding:1rem;margin-bottom:1rem;display:flex;flex-direction:column;gap:.65rem;box-shadow:0 1px 2px #0000000a}.speaking-timer-header{display:flex;align-items:center;justify-content:space-between}.speaking-timer-label{font-size:.7rem;font-weight:900;color:#475569;text-transform:uppercase;letter-spacing:.05em;display:flex;align-items:center;gap:.35rem}.speaking-timer-btn-toggle{padding:.35rem .85rem;border-radius:9999px;font-size:.75rem;font-weight:700;color:#fff;border:none;cursor:pointer;display:inline-flex;align-items:center;gap:.35rem;transition:all .2s}.speaking-timer-btn-reset{padding:.35rem;border-radius:9999px;background-color:#e2e8f0;color:#475569;border:none;cursor:pointer;display:inline-flex;align-items:center;justify-content:center;transition:all .2s}.speaking-timer-btn-reset:hover{background-color:#cbd5e1;color:#0f172a}.speaking-timer-progress{height:6px;background-color:#e2e8f0;border-radius:9999px;overflow:hidden}.speaking-timer-progress-bar{height:100%;border-radius:9999px;transition:width .3s ease}.speaking-timer-phases{display:flex;gap:.35rem;flex-wrap:wrap}.speaking-timer-phase-badge{font-size:.65rem;font-weight:700;padding:.2rem .5rem;border-radius:6px;border:1px solid}.speaking-timer-clock{font-family:monospace;font-size:1.5rem;font-weight:900;color:#0f172a}.speaking-timer-hint{font-size:.7rem;color:var(--fb-text-muted);font-style:italic}.flipbook-model-answer-card{background-color:var(--fb-gold-bg);border:1px solid #fde68a;border-radius:16px;padding:1rem 1.25rem;box-shadow:0 1px 3px #00000008;margin-bottom:1rem}.flipbook-model-answer-text{font-size:.85rem;color:#1e293b;line-height:1.7;font-family:serif;font-style:italic}.flipbook-canonical-badge{font-size:.6rem;background-color:#d1fae5;color:#065f46;font-weight:700;padding:.15rem .5rem;border-radius:9999px;border:1px solid #6ee7b7}.flipbook-vocab-card,[data-testid^=vocab-card-]{background-color:#fff;border:1px solid var(--fb-border-light);border-radius:16px;padding:.85rem 1rem;box-shadow:0 1px 3px #00000008;display:flex;align-items:flex-start;gap:.75rem;margin-bottom:.5rem}.flipbook-vocab-thumb{width:3.5rem;height:3.5rem;background-color:#f1f5f9;border:1px solid var(--fb-border-light);border-radius:12px;flex-shrink:0;display:flex;align-items:center;justify-content:center;overflow:hidden}.flipbook-vocab-word{font-weight:900;color:var(--fb-blue);font-size:.85rem}.flipbook-vocab-ipa{font-size:.7rem;font-family:monospace;color:var(--fb-text-subtle);margin-left:.35rem}.flipbook-vocab-meaning{color:#334155;font-size:.75rem;font-weight:500;margin-top:.15rem}.flipbook-vocab-example{color:var(--fb-text-muted);font-size:.7rem;font-style:italic;margin-top:.2rem}.flipbook-drawer-overlay,[data-testid=toc-drawer]{position:fixed;top:0;right:0;bottom:0;left:0;background-color:#000000a6;-webkit-backdrop-filter:blur(6px);backdrop-filter:blur(6px);z-index:100;display:flex;justify-content:flex-end}.flipbook-drawer-panel{background-color:#fff;width:100%;max-width:28rem;height:100%;box-shadow:-10px 0 30px #00000040;display:flex;flex-direction:column;padding:1.5rem;animation:flipbookSlideIn .3s cubic-bezier(.16,1,.3,1)}@keyframes flipbookSlideIn{0%{transform:translate(100%)}to{transform:translate(0)}}.flipbook-drawer-header{display:flex;align-items:center;justify-content:space-between;border-bottom:1px solid var(--fb-border-light);padding-bottom:.75rem;margin-bottom:1rem}.flipbook-drawer-close{padding:.35rem;border-radius:8px;border:none;background:transparent;cursor:pointer;color:var(--fb-text-muted);transition:all .2s}.flipbook-drawer-close:hover{background-color:#f1f5f9;color:var(--fb-text-dark)}.flipbook-drawer-cover-jump{padding:.75rem 1rem;margin-bottom:.75rem;border-radius:14px;border:1px solid var(--fb-border-light);background-color:#fef3c7;cursor:pointer;display:flex;align-items:center;justify-content:space-between;transition:all .2s}.flipbook-drawer-cover-jump:hover{background-color:#fde68a}.flipbook-drawer-items{flex:1;overflow-y:auto;display:flex;flex-direction:column;gap:.5rem;padding-right:.25rem}.flipbook-drawer-item{padding:.75rem 1rem;border-radius:12px;border:1px solid var(--fb-border-light);background-color:#fff;cursor:pointer;display:flex;align-items:center;justify-content:space-between;transition:all .2s}.flipbook-drawer-item:hover{border-color:#93c5fd;background-color:#eff6ff80}.flipbook-drawer-item.is-active{background-color:var(--fb-blue);border-color:var(--fb-blue);color:#fff;box-shadow:0 4px 6px -1px #2563eb40}.flipbook-drawer-item.is-active *{color:#fff!important}.flipbook-scrollbar::-webkit-scrollbar{width:5px}.flipbook-scrollbar::-webkit-scrollbar-track{background:transparent}.flipbook-scrollbar::-webkit-scrollbar-thumb{background:#cbd5e1;border-radius:9999px}.flipbook-scrollbar::-webkit-scrollbar-thumb:hover{background:#94a3b8}.flipbook-explorer-page .flex,.flipbook-perspective-container .flex{display:flex}.flipbook-explorer-page .inline-flex,.flipbook-perspective-container .inline-flex{display:inline-flex}.flipbook-explorer-page .flex-col,.flipbook-perspective-container .flex-col{flex-direction:column}.flipbook-explorer-page .flex-wrap,.flipbook-perspective-container .flex-wrap{flex-wrap:wrap}.flipbook-explorer-page .items-center,.flipbook-perspective-container .items-center{align-items:center}.flipbook-explorer-page .items-start,.flipbook-perspective-container .items-start{align-items:flex-start}.flipbook-explorer-page .justify-between,.flipbook-perspective-container .justify-between{justify-content:space-between}.flipbook-explorer-page .justify-center,.flipbook-perspective-container .justify-center{justify-content:center}.flipbook-explorer-page .flex-1,.flipbook-perspective-container .flex-1{flex:1 1 0%}.flipbook-explorer-page .shrink-0,.flipbook-perspective-container .shrink-0{flex-shrink:0}.flipbook-explorer-page .space-y-2>*+*,.flipbook-perspective-container .space-y-2>*+*{margin-top:.5rem}.flipbook-explorer-page .space-y-2\.5>*+*,.flipbook-perspective-container .space-y-2\.5>*+*{margin-top:.625rem}.flipbook-explorer-page .space-y-3>*+*,.flipbook-perspective-container .space-y-3>*+*{margin-top:.75rem}.flipbook-explorer-page .space-y-4>*+*,.flipbook-perspective-container .space-y-4>*+*{margin-top:1rem}.flipbook-explorer-page .space-y-6>*+*,.flipbook-perspective-container .space-y-6>*+*{margin-top:1.5rem}.flipbook-explorer-page .gap-1,.flipbook-perspective-container .gap-1{gap:.25rem}.flipbook-explorer-page .gap-1\.5,.flipbook-perspective-container .gap-1\.5{gap:.375rem}.flipbook-explorer-page .gap-2,.flipbook-perspective-container .gap-2{gap:.5rem}.flipbook-explorer-page .gap-2\.5,.flipbook-perspective-container .gap-2\.5{gap:.625rem}.flipbook-explorer-page .gap-3,.flipbook-perspective-container .gap-3{gap:.75rem}.flipbook-explorer-page .gap-4,.flipbook-perspective-container .gap-4{gap:1rem}.flipbook-explorer-page .w-full,.flipbook-perspective-container .w-full{width:100%}.flipbook-explorer-page .h-full,.flipbook-perspective-container .h-full{height:100%}.flipbook-explorer-page .text-white,.flipbook-perspective-container .text-white{color:#fff}.flipbook-explorer-page .text-amber-400,.flipbook-perspective-container .text-amber-400{color:#fbbf24}.flipbook-explorer-page .text-amber-300,.flipbook-perspective-container .text-amber-300{color:#fcd34d}.flipbook-explorer-page .text-slate-400,.flipbook-perspective-container .text-slate-400{color:#94a3b8}.flipbook-explorer-page .text-slate-300,.flipbook-perspective-container .text-slate-300{color:#cbd5e1}.flipbook-explorer-page .text-slate-800,.flipbook-perspective-container .text-slate-800{color:#1e293b}.flipbook-explorer-page .text-slate-900,.flipbook-perspective-container .text-slate-900{color:#0f172a}.flipbook-explorer-page .text-blue-600,.flipbook-perspective-container .text-blue-600{color:#2563eb}.flipbook-explorer-page .bg-amber-400,.flipbook-perspective-container .bg-amber-400{background-color:#fbbf24}.flipbook-explorer-page .bg-slate-900,.flipbook-perspective-container .bg-slate-900{background-color:#0f172a}.flipbook-explorer-page .bg-slate-800,.flipbook-perspective-container .bg-slate-800{background-color:#1e293b}.flipbook-explorer-page .rounded-xl,.flipbook-perspective-container .rounded-xl{border-radius:12px}.flipbook-explorer-page .rounded-2xl,.flipbook-perspective-container .rounded-2xl{border-radius:16px}.flipbook-explorer-page .rounded-3xl,.flipbook-perspective-container .rounded-3xl{border-radius:24px}.flipbook-explorer-page .rounded-full,.flipbook-perspective-container .rounded-full{border-radius:9999px}.flipbook-explorer-page .shadow-md,.flipbook-perspective-container .shadow-md{box-shadow:0 4px 6px -1px #0000001a,0 2px 4px -2px #0000001a}.flipbook-explorer-page .shadow-lg,.flipbook-perspective-container .shadow-lg{box-shadow:0 10px 15px -3px #0000001a,0 4px 6px -4px #0000001a}.flipbook-explorer-page .shadow-xl,.flipbook-perspective-container .shadow-xl{box-shadow:0 20px 25px -5px #0000001a,0 8px 10px -6px #0000001a}.flipbook-explorer-page button,.flipbook-perspective-container button{font-family:inherit}:root{--primary-50: #eff6ff;--primary-100: #dbeafe;--primary-200: #bfdbfe;--primary-300: #93c5fd;--primary-400: #60a5fa;--primary-500: #3b82f6;--primary-600: #2563eb;--primary-700: #1d4ed8;--primary-800: #1e40af;--primary-900: #1e3a8a;--accent-speaking: #3b82f6;--accent-listening: #10b981;--accent-writing: #8b5cf6;--accent-thptqg: #f59e0b;--accent-toeic: #ec4899;--surface-bg: #f8fafc;--surface-card: #ffffff;--surface-subtle: #f1f5f9;--surface-border: #e2e8f0;--text-main: #0f172a;--text-muted: #64748b;--text-subtle: #94a3b8;--text-inverse: #ffffff;--status-success: #10b981;--status-warning: #f59e0b;--status-danger: #ef4444;--status-info: #0ea5e9;--font-sans: "Plus Jakarta Sans", system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;--radius-sm: 6px;--radius-md: 10px;--radius-lg: 16px;--radius-xl: 24px;--radius-full: 9999px;--shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, .05);--shadow-md: 0 4px 6px -1px rgba(0, 0, 0, .07), 0 2px 4px -2px rgba(0, 0, 0, .05);--shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, .08), 0 4px 6px -4px rgba(0, 0, 0, .04);--shadow-glow: 0 0 25px -5px rgba(37, 99, 235, .2);--transition-fast: .15s ease;--transition-normal: .25s cubic-bezier(.4, 0, .2, 1)}*{box-sizing:border-box;margin:0;padding:0}body{font-family:var(--font-sans);background-color:var(--surface-bg);color:var(--text-main);line-height:1.6;-webkit-font-smoothing:antialiased;min-height:100vh;overflow-x:hidden}.container{max-width:1200px;margin:0 auto;padding:0 1.5rem}.header{position:sticky;top:0;z-index:50;background:#ffffffd9;-webkit-backdrop-filter:blur(12px);backdrop-filter:blur(12px);border-bottom:1px solid var(--surface-border);padding:.875rem 0}.header-inner{display:flex;justify-content:space-between;align-items:center}.brand-logo{display:flex;align-items:center;gap:.75rem;text-decoration:none;font-weight:800;font-size:1.25rem;color:var(--primary-700)}.nav-links{display:flex;align-items:center;gap:1.25rem;list-style:none}.nav-link{text-decoration:none;color:var(--text-muted);font-weight:600;font-size:.95rem;padding:.5rem .75rem;border-radius:var(--radius-sm);transition:var(--transition-fast)}.nav-link:hover,.nav-link.active{color:var(--primary-600);background-color:var(--primary-50)}.btn{display:inline-flex;align-items:center;justify-content:center;gap:.5rem;padding:.625rem 1.25rem;font-size:.95rem;font-weight:600;border-radius:var(--radius-md);border:1px solid transparent;cursor:pointer;transition:var(--transition-fast);text-decoration:none}.btn-primary{background-color:var(--primary-600);color:var(--text-inverse)}.btn-primary:hover{background-color:var(--primary-700);box-shadow:var(--shadow-glow)}.btn-outline{background:transparent;border-color:var(--surface-border);color:var(--text-main)}.btn-outline:hover{border-color:var(--primary-400);background:var(--surface-subtle)}.btn-danger{background-color:var(--status-danger);color:var(--text-inverse)}.hero{padding:4.5rem 0 3.5rem;text-align:center;background:radial-gradient(circle at 50% 0%,#eff6ff,#f8fafc 70%)}.hero-badge{display:inline-flex;align-items:center;gap:.5rem;padding:.375rem 1rem;background:var(--primary-100);color:var(--primary-800);font-size:.85rem;font-weight:700;border-radius:var(--radius-full);margin-bottom:1.5rem}.hero-title{font-size:3rem;font-weight:800;line-height:1.2;letter-spacing:-.02em;margin-bottom:1.25rem;color:var(--text-main)}.hero-title span{color:var(--primary-600)}.hero-subtitle{font-size:1.2rem;color:var(--text-muted);max-width:650px;margin:0 auto 2rem}.grid-5{display:grid;grid-template-columns:repeat(auto-fit,minmax(220px,1fr));gap:1.5rem}.card{background:var(--surface-card);border:1px solid var(--surface-border);border-radius:var(--radius-lg);padding:1.5rem;box-shadow:var(--shadow-sm);transition:var(--transition-normal);display:flex;flex-direction:column}.card:hover{transform:translateY(-3px);box-shadow:var(--shadow-lg);border-color:var(--primary-200)}.card-badge{align-self:flex-start;padding:.25rem .625rem;font-size:.75rem;font-weight:700;border-radius:var(--radius-full);text-transform:uppercase;margin-bottom:1rem}.card-title{font-size:1.25rem;font-weight:700;margin-bottom:.5rem}.card-desc{font-size:.9rem;color:var(--text-muted);flex-grow:1;margin-bottom:1.25rem}.form-group{margin-bottom:1.25rem}.form-label{display:block;font-size:.875rem;font-weight:600;margin-bottom:.375rem;color:var(--text-main)}.form-control{width:100%;padding:.625rem .875rem;font-size:.95rem;font-family:inherit;border:1px solid var(--surface-border);border-radius:var(--radius-md);background:var(--surface-card);transition:var(--transition-fast)}.form-control:focus{outline:none;border-color:var(--primary-500);box-shadow:0 0 0 3px var(--primary-100)}.state-container{text-align:center;padding:3rem 1.5rem;background:var(--surface-card);border:1px dashed var(--surface-border);border-radius:var(--radius-lg);margin:1.5rem 0}.state-icon{width:48px;height:48px;margin:0 auto 1rem;color:var(--text-muted)}.spinner{width:36px;height:36px;border:3px solid var(--primary-100);border-top-color:var(--primary-600);border-radius:50%;animation:spin .8s linear infinite;margin:0 auto 1rem}@keyframes spin{to{transform:rotate(360deg)}}.footer{margin-top:5rem;border-top:1px solid var(--surface-border);padding:2.5rem 0;background:var(--surface-card);font-size:.875rem;color:var(--text-muted);text-align:center}html{overflow-x:hidden;max-width:100vw}body{font-family:var(--font-sans);background-color:var(--surface-bg);color:var(--text-main);line-height:1.6;-webkit-font-smoothing:antialiased;min-height:100vh;overflow-x:hidden;max-width:100vw}.app-layout{overflow-x:hidden;max-width:100vw}@media(max-width:768px){.container{padding:0 .75rem}.header-inner{flex-direction:column;align-items:flex-start;gap:.625rem}.hero-title{font-size:2.2rem}.nav-links{display:flex;flex-wrap:wrap;gap:.35rem .5rem;max-width:100%}.nav-link{padding:.35rem .5rem;font-size:.85rem}.grid-5{grid-template-columns:1fr}}