:root{--bg-main:#0b0f19;--bg-card:#1e293bb3;--bg-card-hover:#334155cc;--bg-card-solid:#1e293b;--border-color:#ffffff1a;--border-highlight:#6366f166;--text-main:#f8fafc;--text-muted:#94a3b8;--text-dim:#64748b;--accent-indigo:#6366f1;--accent-indigo-glow:#6366f159;--accent-purple:#8b5cf6;--accent-emerald:#10b981;--accent-amber:#f59e0b;--accent-rose:#f43f5e;--accent-cyan:#06b6d4;--font-family:"Inter", system-ui, -apple-system, sans-serif;--font-heading:"Outfit", "Inter", system-ui, sans-serif;--radius-sm:8px;--radius-md:14px;--radius-lg:20px;--shadow-glow:0 0 25px #6366f140;--shadow-card:0 10px 30px -10px #00000080}*{box-sizing:border-box;margin:0;padding:0}body{background-color:var(--bg-main);color:var(--text-main);font-family:var(--font-family);background-image:radial-gradient(circle at 15% 20%,#6366f11f 0%,#0000 40%),radial-gradient(circle at 85% 75%,#8b5cf61f 0%,#0000 40%);background-attachment:fixed;flex-direction:column;min-height:100vh;line-height:1.5;display:flex}.app-header{-webkit-backdrop-filter:blur(12px);border-bottom:1px solid var(--border-color);z-index:100;background:#0f172ad9;padding:.8rem 1.5rem;position:sticky;top:0}.header-content{justify-content:space-between;align-items:center;gap:1rem;max-width:1400px;margin:0 auto;display:flex}.brand{align-items:center;gap:1rem;display:flex}.back-link{color:var(--text-muted);border-radius:var(--radius-sm);background:#ffffff0d;padding:.4rem .8rem;font-size:.9rem;font-weight:500;text-decoration:none;transition:color .2s}.back-link:hover{color:var(--text-main);background:#ffffff1a}.brand-title{align-items:center;gap:.6rem;display:flex}.brand-title h1{font-family:var(--font-heading);letter-spacing:-.02em;background:linear-gradient(135deg,#fff 0%,#cbd5e1 100%);-webkit-text-fill-color:transparent;-webkit-background-clip:text;font-size:1.35rem;font-weight:700}.badge-icon{font-size:1.4rem}.accent-badge{background:linear-gradient(135deg, var(--accent-indigo), var(--accent-purple));color:#fff;text-transform:uppercase;letter-spacing:.05em;-webkit-text-fill-color:initial;border-radius:6px;padding:.2rem .5rem;font-size:.75rem;font-weight:700}.header-stats{align-items:center;gap:.75rem;display:flex}.stat-pill{border:1px solid var(--border-color);background:#1e293bcc;border-radius:30px;align-items:center;gap:.4rem;padding:.35rem .85rem;font-size:.9rem;display:flex}.stat-val{color:var(--accent-amber);font-weight:700}.stat-lbl{color:var(--text-muted);font-size:.8rem}.main-container{flex:1;grid-template-columns:340px 1fr;gap:1.5rem;width:100%;max-width:1400px;margin:1.5rem auto;padding:0 1.5rem;display:grid}@media (width<=1024px){.main-container{grid-template-columns:1fr}}.sidebar-panel{flex-direction:column;gap:1.25rem;display:flex}.panel-card{background:var(--bg-card);-webkit-backdrop-filter:blur(16px);border:1px solid var(--border-color);border-radius:var(--radius-md);box-shadow:var(--shadow-card);padding:1.25rem}.panel-header{border-bottom:1px solid var(--border-color);justify-content:space-between;align-items:center;margin-bottom:1rem;padding-bottom:.6rem;display:flex}.panel-header h2,.panel-header h3{font-family:var(--font-heading);color:#f1f5f9;font-size:1.05rem;font-weight:700}.badge-level{color:var(--accent-indigo);background:#6366f133;border:1px solid #6366f166;border-radius:4px;padding:.15rem .5rem;font-size:.7rem;font-weight:600}.lesson-list{flex-direction:column;gap:.6rem;display:flex}.lesson-item{border:1px solid var(--border-color);border-radius:var(--radius-sm);cursor:pointer;background:#0f172a99;flex-direction:column;gap:.3rem;padding:.85rem;transition:all .2s;display:flex}.lesson-item:hover{background:var(--bg-card-hover);border-color:var(--border-highlight);transform:translateY(-2px)}.lesson-item.active{border-color:var(--accent-indigo);background:#6366f126;box-shadow:0 0 15px #6366f133}.lesson-item-header{justify-content:space-between;align-items:center;display:flex}.lesson-num{color:var(--accent-purple);text-transform:uppercase;font-size:.75rem;font-weight:700}.lesson-item-title{color:#f8fafc;font-size:.95rem;font-weight:600}.lesson-item-sub{color:var(--text-muted);font-size:.8rem}.setting-group{margin-bottom:.9rem}.setting-group:last-child{margin-bottom:0}.setting-group label{color:var(--text-muted);margin-bottom:.35rem;font-size:.825rem;font-weight:500;display:block}.form-select{border:1px solid var(--border-color);width:100%;color:var(--text-main);border-radius:var(--radius-sm);cursor:pointer;background:#0f172acc;outline:none;padding:.5rem .75rem;font-size:.85rem}.form-select:focus{border-color:var(--accent-indigo)}.slider-header{justify-content:space-between;align-items:center;display:flex}.slider-val{color:var(--accent-indigo);font-size:.85rem;font-weight:700}.form-range{width:100%;accent-color:var(--accent-indigo);cursor:pointer}.checkbox-label{color:var(--text-muted);cursor:pointer;align-items:center;gap:.5rem;font-size:.825rem;display:flex}.arena-panel{flex-direction:column;gap:1.25rem;display:flex}.lesson-banner{border:1px solid var(--border-highlight);border-radius:var(--radius-md);box-shadow:var(--shadow-card);background:linear-gradient(135deg,#1e293be6 0%,#0f172af2 100%);padding:1.25rem 1.5rem;position:relative;overflow:hidden}.banner-meta{gap:.5rem;margin-bottom:.4rem;display:flex}.topic-tag{color:#a5b4fc;background:#6366f133;border-radius:4px;padding:.15rem .6rem;font-size:.75rem;font-weight:600}.level-tag{color:#6ee7b7;background:#10b98133;border-radius:4px;padding:.15rem .6rem;font-size:.75rem;font-weight:600}.lesson-title{font-family:var(--font-heading);color:#fff;margin-bottom:.2rem;font-size:1.4rem;font-weight:700}.lesson-desc{color:var(--text-muted);font-size:.9rem}.mode-tabs{border-radius:var(--radius-md);border:1px solid var(--border-color);background:#0f172ab3;gap:.6rem;padding:.35rem;display:flex}.mode-tab{color:var(--text-muted);border-radius:var(--radius-sm);cursor:pointer;background:0 0;border:none;flex:1;justify-content:center;align-items:center;gap:.4rem;padding:.6rem .8rem;font-size:.875rem;font-weight:600;transition:all .2s;display:flex}.mode-tab:hover{color:var(--text-main);background:#ffffff0d}.mode-tab.active{background:var(--accent-indigo);color:#fff;box-shadow:0 4px 12px #6366f14d}.dialogue-card{background:var(--bg-card);-webkit-backdrop-filter:blur(16px);backdrop-filter:blur(16px);border:1px solid var(--border-color);border-radius:var(--radius-md);flex-direction:column;gap:1rem;padding:1.25rem;display:flex}.dialogue-toolbar{border-bottom:1px solid var(--border-color);flex-wrap:wrap;justify-content:space-between;align-items:center;gap:1rem;padding-bottom:.8rem;display:flex}.role-selector{align-items:center;gap:.6rem;display:flex}.role-label{color:var(--text-muted);font-size:.825rem;font-weight:500}.role-btns{border-radius:var(--radius-sm);border:1px solid var(--border-color);background:#0f172acc;gap:.3rem;padding:.2rem;display:flex}.role-btn{color:var(--text-muted);cursor:pointer;background:0 0;border:none;border-radius:6px;padding:.3rem .7rem;font-size:.8rem;font-weight:600;transition:all .2s}.role-btn.active{color:#a5b4fc;background:#6366f14d;border:1px solid #6366f180}.playback-controls{gap:.5rem;display:flex}.btn-primary{background:linear-gradient(135deg, var(--accent-indigo) 0%, var(--accent-purple) 100%);color:#fff;border-radius:var(--radius-sm);cursor:pointer;border:none;align-items:center;gap:.4rem;padding:.5rem 1.1rem;font-size:.875rem;font-weight:600;transition:transform .15s,box-shadow .15s;display:inline-flex;box-shadow:0 4px 14px #6366f14d}.btn-primary:hover{transform:translateY(-1px);box-shadow:0 6px 20px #6366f166}.btn-secondary{color:#fca5a5;border-radius:var(--radius-sm);cursor:pointer;background:#ef444433;border:1px solid #ef444466;align-items:center;gap:.4rem;padding:.5rem 1rem;font-size:.875rem;font-weight:600;display:inline-flex}.btn-ghost{color:var(--text-muted);border:1px solid var(--border-color);border-radius:var(--radius-sm);cursor:pointer;background:#ffffff0d;padding:.4rem .8rem;font-size:.8rem;font-weight:500;transition:background .2s,color .2s}.btn-ghost:hover{color:var(--text-main);background:#ffffff1a}.audio-waveform-bar{border-radius:var(--radius-sm);background:#6366f11a;border:1px solid #6366f14d;align-items:center;gap:.4rem;padding:.5rem 1rem;display:flex}.wave-bar{background:var(--accent-indigo);border-radius:2px;width:4px;height:16px;animation:1s ease-in-out infinite alternate wavePulse}.wave-bar:nth-child(2){animation-delay:.2s}.wave-bar:nth-child(3){animation-delay:.4s}.wave-bar:nth-child(4){animation-delay:.6s}.wave-bar:nth-child(5){animation-delay:.8s}@keyframes wavePulse{0%{opacity:.4;height:6px}to{opacity:1;height:22px}}.speech-status-text{color:#a5b4fc;margin-left:.5rem;font-size:.825rem;font-weight:600}.chat-stream{flex-direction:column;gap:.9rem;max-height:480px;padding-right:.4rem;display:flex;overflow-y:auto}.chat-bubble{align-items:flex-start;gap:.8rem;transition:all .25s;display:flex}.chat-avatar{border-radius:50%;flex-shrink:0;justify-content:center;align-items:center;width:38px;height:38px;font-size:.9rem;font-weight:700;display:flex;box-shadow:0 4px 10px #0000004d}.avatar-a{color:#e0f2fe;background:linear-gradient(135deg,#0284c7,#0369a1)}.avatar-b{color:#f3e8ff;background:linear-gradient(135deg,#7c3aed,#6d28d9)}.bubble-content{border:1px solid var(--border-color);border-radius:var(--radius-sm);background:#0f172acc;flex-direction:column;gap:.3rem;max-width:85%;padding:.75rem 1rem;display:flex;position:relative}.chat-bubble.active-speech .bubble-content{border-color:var(--accent-indigo);background:#1e293bf2;box-shadow:0 0 18px #6366f14d}.speaker-name{color:var(--text-muted);font-size:.75rem;font-weight:700}.text-en{color:#f8fafc;font-size:1rem;font-weight:600}.text-vi{color:var(--text-muted);font-size:.825rem}.bubble-controls{align-items:center;gap:.5rem;margin-top:.3rem;display:flex}.btn-speak-icon{color:var(--text-muted);cursor:pointer;background:#ffffff14;border:none;border-radius:50%;justify-content:center;align-items:center;width:28px;height:28px;font-size:.85rem;transition:all .2s;display:flex}.btn-speak-icon:hover{background:var(--accent-indigo);color:#fff}.roleplay-deck{border:2px solid var(--accent-indigo);border-radius:var(--radius-md);text-align:center;box-shadow:var(--shadow-glow);background:linear-gradient(135deg,#1e293bf2 0%,#0f172afa 100%);flex-direction:column;align-items:center;gap:1rem;padding:1.25rem;display:flex}.deck-turn-indicator{color:#a5b4fc;font-size:.95rem}.target-sentence-box{border-radius:var(--radius-sm);background:#0f172acc;border:1px solid #6366f14d;flex-direction:column;gap:.2rem;width:100%;padding:.85rem 1.5rem;display:flex}.target-en{color:#fff;font-size:1.25rem;font-weight:700}.target-vi{color:var(--text-muted);font-size:.875rem}.mic-container{flex-direction:column;align-items:center;gap:.5rem;display:flex}.mic-btn{background:linear-gradient(135deg, var(--accent-indigo) 0%, var(--accent-purple) 100%);color:#fff;cursor:pointer;border:3px solid #fff3;border-radius:50%;justify-content:center;align-items:center;width:68px;height:68px;font-size:1.8rem;transition:transform .2s,box-shadow .2s;display:flex;box-shadow:0 8px 25px #6366f166}.mic-btn:hover{transform:scale(1.08);box-shadow:0 10px 30px #6366f199}.mic-btn.recording{background:linear-gradient(135deg, var(--accent-rose) 0%, #dc2626 100%);animation:1.2s infinite micPulse}@keyframes micPulse{0%{box-shadow:0 0 #f43f5e99}70%{box-shadow:0 0 0 20px #f43f5e00}to{box-shadow:0 0 #f43f5e00}}.mic-hint{color:var(--text-muted);font-size:.8rem}.speech-feedback{border:1px solid var(--border-color);border-radius:var(--radius-sm);background:#0f172ae6;width:100%;padding:.75rem 1.25rem}.feedback-label{color:var(--text-muted);font-size:.75rem}.feedback-text{color:#fbbf24;margin:.2rem 0;font-size:1rem;font-weight:600}.accuracy-badge{color:var(--accent-emerald);font-size:.8rem;font-weight:700}.deck-actions{gap:.6rem;display:flex}.quiz-deck{border:1px solid var(--border-highlight);border-radius:var(--radius-md);background:#0f172acc;flex-direction:column;gap:1rem;padding:1.25rem;display:flex}.quiz-question-box{text-align:center}.quiz-prompt{color:var(--text-muted);font-size:.85rem}.quiz-sentence{color:#fff;margin-top:.4rem;font-size:1.2rem;font-weight:700}.quiz-options-grid{grid-template-columns:1fr 1fr;gap:.8rem;display:grid}@media (width<=600px){.quiz-options-grid{grid-template-columns:1fr}}.quiz-opt-btn{border:1px solid var(--border-color);color:var(--text-main);border-radius:var(--radius-sm);cursor:pointer;text-align:left;background:#1e293be6;padding:.85rem 1rem;font-size:.95rem;font-weight:600;transition:all .2s}.quiz-opt-btn:hover{border-color:var(--accent-indigo);background:#6366f126}.quiz-opt-btn.correct{border-color:var(--accent-emerald)!important;color:#34d399!important;background:#10b98133!important}.quiz-opt-btn.wrong{border-color:var(--accent-rose)!important;color:#fca5a5!important;background:#ef444433!important}.quiz-feedback-box{text-align:center;border-radius:var(--radius-sm);background:#1e293be6;padding:.8rem}.quiz-feedback-msg{font-size:1rem;font-weight:700}.pattern-card{background:var(--bg-card);-webkit-backdrop-filter:blur(16px);backdrop-filter:blur(16px);border:1px solid var(--border-color);border-radius:var(--radius-md);padding:1.25rem}.pattern-card h3{font-family:var(--font-heading);color:#f1f5f9;margin-bottom:.9rem;font-size:1.05rem;font-weight:700}.pattern-grid{grid-template-columns:repeat(auto-fit,minmax(260px,1fr));gap:.8rem;display:grid}.pattern-item{border:1px solid var(--border-color);border-radius:var(--radius-sm);background:#0f172a99;padding:.8rem}.pattern-en{color:var(--accent-indigo);font-size:.9rem;font-weight:700}.pattern-vi{color:var(--text-muted);margin-top:.2rem;font-size:.8rem}.hidden{display:none!important}.toast-notification{color:#fff;border:1px solid var(--accent-indigo);border-radius:var(--radius-sm);z-index:1000;background:#1e293b;padding:.75rem 1.25rem;font-size:.9rem;font-weight:500;position:fixed;bottom:2rem;right:2rem;box-shadow:0 10px 25px #00000080}