:root{font-family:system-ui,Avenir,Helvetica,Arial,sans-serif;line-height:1.5;font-weight:400;color-scheme:light dark;color:#ffffffde;background-color:#242424;font-synthesis:none;text-rendering:optimizeLegibility;-webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale}a{font-weight:500;color:#646cff;text-decoration:inherit}a:hover{color:#535bf2}body{margin:0;display:flex;place-items:center;min-width:320px;min-height:100vh}h1{font-size:3.2em;line-height:1.1}button{border-radius:8px;border:1px solid transparent;padding:.6em 1.2em;font-size:1em;font-weight:500;font-family:inherit;background-color:#1a1a1a;cursor:pointer;transition:border-color .25s}button:hover{border-color:#646cff}button:focus,button:focus-visible{outline:4px auto -webkit-focus-ring-color}@media(prefers-color-scheme:light){:root{color:#213547;background-color:#fff}a:hover{color:#747bff}button{background-color:#f9f9f9}}.toc-list{list-style:none;padding:0;width:100%;max-width:980px;margin:0 auto}.toc-lesson{font-size:1.05rem;margin:18px 0}.toc-lesson-container{display:flex;align-items:center;gap:40px;background:#2e7d32;color:#fff;padding:16px;border-radius:8px;cursor:pointer;text-decoration:none;box-shadow:0 6px 18px #0000001f;transition:transform .14s ease,box-shadow .14s ease,background .14s ease;outline:none}.toc-lesson-image{flex-shrink:0;width:120px;height:120px;overflow:hidden;border-radius:8px}.toc-lesson-image img{width:100%;height:100%;object-fit:cover}.toc-lesson-content{flex:1;display:flex;flex-direction:column;gap:4px;justify-content:center}.toc-lesson-title{font-weight:600;font-size:1.1rem;margin-bottom:6px;text-align:center}.toc-lesson-container--intermediate{background:#9fe0ff;color:#000}.toc-lesson-container--intermediate .toc-lesson-desc{color:#333}.toc-lesson-container--beginner{background:#2e7d32;color:#fff}.toc-lesson-container--advanced{background:#1e3a8a;color:#fff}.toc-lesson-container:hover,.toc-lesson-container:focus{background:#388e3c;transform:translateY(-3px);box-shadow:0 10px 22px #00000029}.toc-lesson-container--intermediate:hover,.toc-lesson-container--intermediate:focus{background:#7dd3fc;transform:translateY(-3px);box-shadow:0 10px 22px #00000029}.toc-lesson-container--advanced:hover,.toc-lesson-container--advanced:focus{background:#2563eb;transform:translateY(-3px);box-shadow:0 10px 22px #00000029}.toc-lesson-desc{color:#fffc;max-width:880px;text-align:center;line-height:1.5;margin-top:4px}.toc-lesson-desc.collapsed{display:-webkit-box;-webkit-line-clamp:3;-webkit-box-orient:vertical;overflow:hidden;line-clamp:3}.toc-readmore{margin-top:6px;background:transparent;border:none;color:#aeea00;cursor:pointer;font-weight:600;padding:6px 0}.toc-readmore:hover,.toc-readmore:focus{text-decoration:underline;outline:none}.toc-lesson-link{margin-top:8px;font-size:.95rem}.toc-lesson-link a{color:#ffd54f;text-decoration:underline}.board-row{display:flex}.board-square{display:flex;align-items:center;justify-content:center;box-sizing:border-box;border:1px solid #bbb;position:relative}.board-root{display:inline-block;position:relative;border:2px solid #333;padding:6px;background:#222}.drag-ghost{position:fixed;pointer-events:none;z-index:9999}.red-overlay{position:absolute;inset:0;background:#dc143c73;pointer-events:none;border-radius:2px}.board-inner{display:flex;flex-direction:column}.piece-img{pointer-events:none}.about-page{max-width:700px;margin:2.5rem auto 0;background:#f3f6fa;border-radius:14px;box-shadow:0 2px 16px #00000012;padding:2rem 1.5rem 2.5rem}.about-page h2{font-size:1.7rem;margin-bottom:1.2rem;color:#2d2d2d}.about-content{display:flex;align-items:flex-start;gap:1.5rem}@media(max-width:700px){.about-content{flex-direction:column;align-items:center}}.about-img{height:120px;width:auto;border-radius:50%;box-shadow:0 1px 6px #00000014;background:#fff;margin-bottom:1rem}.about-content p{color:#444;font-size:1.1rem;line-height:1.6}.featured-book{margin:2.5rem auto 0;max-width:800px;background:#f3f6fa;border-radius:14px;box-shadow:0 2px 16px #00000012;padding:2rem 1.5rem 2.5rem}.featured-book h2{font-size:1.7rem;margin-bottom:1.2rem;color:#2d2d2d}.featured-book-card{display:flex;align-items:flex-start;gap:1.5rem;background:#fff;border-radius:10px;box-shadow:0 1px 6px #0000000f;padding:1.2rem 1rem;margin-top:.5rem}@media(max-width:700px){.featured-book-card{flex-direction:column;align-items:center}}.featured-book-card img{height:120px;width:auto;border-radius:8px;box-shadow:0 1px 6px #00000014;background:#fff;margin-top:.2rem}.featured-book-card h3{margin:0 0 .5rem;font-size:1.2rem;color:#1a1a1a}.featured-book-card p{margin:0 0 .7rem;color:#444;font-size:1rem;line-height:1.5}.featured-book-card a{color:#2d6cdf;text-decoration:none;font-weight:500;transition:color .2s}.featured-book-card a:hover{color:#174ea6;text-decoration:underline}.books-list{width:100%;max-width:900px;margin:0 auto;background:#fff;border-radius:14px;box-shadow:0 2px 16px #00000014;padding:2rem 1.5rem 2.5rem}.books-list h2{font-size:2rem;margin-bottom:2rem;color:#2d2d2d;letter-spacing:.01em}.books-list ul{list-style:none;padding:0;margin:0;display:grid;grid-template-columns:1fr 1fr;gap:2rem 1.5rem}@media(max-width:700px){.books-list ul{grid-template-columns:1fr}}.book-item{display:flex;align-items:flex-start;background:#f8f9fb;border-radius:10px;box-shadow:0 1px 6px #0000000f;padding:1.2rem 1rem;gap:1.2rem;transition:box-shadow .2s,transform .2s}.book-item:hover{box-shadow:0 4px 18px #00000021;transform:translateY(-2px) scale(1.01)}.book-item img{height:100px;width:auto;border-radius:8px;box-shadow:0 1px 6px #00000014;background:#fff;margin-top:.2rem}.book-item h3{margin:0 0 .5rem;font-size:1.2rem;color:#1a1a1a}.book-item p{margin:0 0 .7rem;color:#444;font-size:1rem;line-height:1.5}.book-item a{color:#2d6cdf;text-decoration:none;font-weight:500;transition:color .2s}.book-item a:hover{color:#174ea6;text-decoration:underline}#root{max-width:1800px;margin:0 auto;padding:2rem;text-align:center}.homepage{background:#f7f7fa;border-radius:16px;box-shadow:0 2px 16px #00000012;padding:2.5rem 2rem 2rem;margin-top:2rem;display:flex;flex-direction:column;align-items:stretch;max-width:1700px;width:100%}.homepage nav{width:100%;flex-wrap:nowrap!important;justify-content:center}.homepage h1{font-size:2.5rem;margin-bottom:1rem;color:#2d2d2d;letter-spacing:.02em}.homepage p{font-size:1.2rem;margin-bottom:2rem;color:#444}.homepage .store-links{display:flex;gap:1.5rem;justify-content:center;align-items:center;margin-top:1rem}.homepage .store-links img{height:60px;width:auto;display:block;box-shadow:0 2px 8px #00000014;border-radius:8px;background:#fff;padding:.3rem .8rem;transition:transform .2s,box-shadow .2s}.homepage .store-links img:hover{transform:scale(1.05);box-shadow:0 4px 16px #00000021}.logo{height:6em;padding:1.5em;will-change:filter;transition:filter .3s}.logo:hover{filter:drop-shadow(0 0 2em #646cffaa)}.logo.react:hover{filter:drop-shadow(0 0 2em #61dafbaa)}@keyframes logo-spin{0%{transform:rotate(0)}to{transform:rotate(360deg)}}@media(prefers-reduced-motion:no-preference){a:nth-of-type(2) .logo{animation:logo-spin infinite 20s linear}}.card{padding:2em}.read-the-docs{color:#888}.lesson-page-wrap{max-width:780px;margin:0 auto;padding:1.5rem 1rem 2rem;background:#f3f6fa;min-height:100vh}.lesson-topbar{display:flex;gap:8px;margin-bottom:1.25rem;flex-wrap:wrap;align-items:center}.btn{display:inline-flex;align-items:center;gap:6px;padding:8px 18px;border-radius:8px;border:none;font-size:.95rem;font-weight:500;cursor:pointer;transition:background .15s,box-shadow .15s,transform .1s}.btn:active{transform:scale(.97)}.btn-secondary{background:#fff;color:#374151;border:1px solid #d1d5db;box-shadow:0 1px 3px #00000012}.btn-secondary:hover{background:#f0f4ff;border-color:#93c5fd}.btn-primary{background:#2563eb;color:#fff;box-shadow:0 1px 4px #2563eb40}.btn-primary:hover{background:#1d4ed8}.btn-success{background:#16a34a;color:#fff;box-shadow:0 1px 4px #16a34a40}.btn-success:hover{background:#15803d}.btn-disabled{background:#e5e7eb;color:#9ca3af;border:1px solid #e5e7eb;cursor:default;pointer-events:none}.btn-audio-on{background:#059669;color:#fff}.btn-audio-on:hover{background:#047857}.btn-audio-off{background:#6b7280;color:#fff}.btn-audio-off:hover{background:#4b5563}.lesson-card{background:#fff;border-radius:12px;box-shadow:0 2px 12px #00000014;padding:1.5rem 1.25rem;margin-bottom:1.25rem;text-align:center}.lesson-card h2{font-size:1.15rem;color:#1f2937;margin:0 0 .4rem}.lesson-card p{font-size:.95rem;color:#4b5563;margin:0}.feedback-banner{border-radius:10px;padding:.85rem 1rem;margin-bottom:1.25rem;text-align:center;font-size:.95rem}.feedback-banner--correct{background:#dcfce7;border:1px solid #86efac;color:#166534}.feedback-banner--incorrect{background:#fee2e2;border:1px solid #fca5a5;color:#991b1b}.feedback-banner .feedback-comment{color:#374151;margin-top:.4rem;font-size:.92rem}.answer-row{display:flex;justify-content:center;gap:20px;margin-bottom:1.25rem}.answer-btn{min-width:110px;padding:12px 32px;font-size:1.15rem;font-weight:700;border-radius:10px;border:2px solid #d1d5db;background:#fff;color:#1f2937;cursor:pointer;transition:background .15s,border-color .15s,transform .1s;box-shadow:0 1px 4px #0000000f}.answer-btn:hover:not(:disabled){background:#f0f4ff;border-color:#93c5fd}.answer-btn:active:not(:disabled){transform:scale(.97)}.answer-btn--correct{background:#dcfce7!important;border-color:#16a34a!important;color:#166534!important}.answer-btn--incorrect{background:#fee2e2!important;border-color:#ef4444!important;color:#991b1b!important}.answer-btn:disabled{cursor:default}.nav-row{display:flex;align-items:center;justify-content:center;gap:16px;margin-top:.5rem}.nav-counter{font-size:.875rem;color:#6b7280;min-width:60px;text-align:center}.exercise-list{list-style:none;padding:0;margin:0}.exercise-list-item{background:#fff;border-radius:10px;box-shadow:0 1px 6px #0000000f;padding:12px 16px;margin-bottom:10px;display:flex;align-items:center;gap:12px}.exercise-list-item-text{flex:1;min-width:0}.exercise-list-item-text strong{display:block;color:#1f2937;font-size:1rem}.exercise-list-item-text span{color:#6b7280;font-size:.88rem}.exercise-list-title{font-size:1.35rem;font-weight:700;color:#1f2937;text-align:center;margin-bottom:1.25rem}.drag-hint{text-align:center;color:#6b7280;font-size:.9rem;margin-bottom:.75rem}.speaking-badge{font-size:.8rem;color:#059669;background:#d1fae5;border-radius:20px;padding:3px 10px;display:inline-flex;align-items:center;gap:4px}