:root{--bg: #0d0d0f;--surface: #18181c;--surface2: #22222a;--surface3: #2a2a36;--border: rgba(255, 255, 255, .08);--border2: rgba(255, 255, 255, .14);--text: #f0f0f4;--text2: #9a9aaf;--text3: #5c5c70;--accent: #7c6af5;--accent2: #a695ff;--accent-bg: rgba(124, 106, 245, .12);--accent-border: rgba(124, 106, 245, .3);--green: #3ecf8e;--green-bg: rgba(62, 207, 142, .1);--red: #f87171;--amber: #fbbf24;--radius: 12px;--radius-sm: 8px;--radius-lg: 16px}.app{min-height:100vh;display:flex;flex-direction:column}.main{max-width:1200px;width:100%;margin:0 auto;padding:0 24px;flex:1}.header{padding:16px 24px;display:flex;align-items:center;justify-content:space-between;border-bottom:1px solid var(--border);background:#0d0d0fe6;-webkit-backdrop-filter:blur(12px);backdrop-filter:blur(12px);position:sticky;top:0;z-index:100}.header-logo{display:flex;align-items:center;gap:10px;font-size:18px;font-weight:700;letter-spacing:-.4px}.header-logo-icon{width:32px;height:32px;background:var(--accent);border-radius:8px;display:flex;align-items:center;justify-content:center;font-size:16px}.header-logo-accent{color:var(--accent2)}.header-badge{font-size:11px;padding:4px 10px;background:var(--accent-bg);border:1px solid var(--accent-border);border-radius:100px;color:var(--accent2);font-weight:500;letter-spacing:.3px}.api-banner{margin:16px 24px 0;display:flex;align-items:flex-start;gap:12px;background:#fbbf2414;border:1px solid rgba(251,191,36,.25);border-radius:12px;padding:12px 16px;max-width:1152px}.api-banner-icon{font-size:18px}.api-banner-text{font-size:14px;color:var(--text2);line-height:1.6}.api-banner-text strong{color:var(--text)}.api-banner-text code{background:#0000004d;padding:1px 6px;border-radius:4px;font-family:SF Mono,monospace;font-size:12px;color:var(--accent2)}.api-banner-link{color:var(--amber)}.error-banner{background:#f871711a;border:1px solid rgba(248,113,113,.3);border-radius:var(--radius-sm);padding:12px 16px;font-size:13px;color:#fca5a5;margin:16px 0}.hero{padding:56px 0 40px;text-align:center}.hero-title{font-size:clamp(28px,5vw,48px);font-weight:800;letter-spacing:-1.5px;line-height:1.15;margin-bottom:14px}.hero-highlight{background:linear-gradient(135deg,var(--accent2),var(--green));-webkit-background-clip:text;background-clip:text;-webkit-text-fill-color:transparent}.hero-subtitle{color:var(--text2);font-size:17px;max-width:520px;margin:0 auto 32px;line-height:1.6}.hero-input-row{display:flex;gap:10px;max-width:640px;margin:0 auto;flex-wrap:wrap;justify-content:center}.hero-input-wrap{flex:1;min-width:280px;position:relative}.hero-input-icon{position:absolute;left:14px;top:50%;transform:translateY(-50%);font-size:15px;pointer-events:none}.hero-input{width:100%;height:48px;background:var(--surface);border:1px solid var(--border2);border-radius:var(--radius);color:var(--text);font-size:15px;padding:0 16px 0 42px;outline:none}.hero-input:focus{border-color:var(--accent)}.hero-button{height:48px;padding:0 24px;background:var(--accent);color:#fff;border:none;border-radius:var(--radius);font-size:15px;font-weight:600;cursor:pointer;white-space:nowrap;transition:background .2s,transform .2s}.hero-button:hover{background:#8f7fff;transform:translateY(-1px)}.hero-tags{display:flex;align-items:center;justify-content:center;gap:8px;margin-top:18px;flex-wrap:wrap}.hero-tags-label{color:var(--text3);font-size:13px}.hero-tag{font-size:12px;padding:4px 12px;border-radius:100px;border:1px solid var(--border2);color:var(--text2);background:var(--surface)}.loading-card{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius-lg);padding:56px 40px;text-align:center;margin:40px auto;max-width:480px}.loading-spinner-wrap{display:flex;justify-content:center;margin-bottom:24px}.loading-spinner{width:44px;height:44px;border:3px solid var(--border2);border-top-color:var(--accent);border-radius:50%;animation:spin .8s linear infinite}@keyframes spin{to{transform:rotate(360deg)}}.loading-title{font-size:18px;font-weight:600;margin-bottom:6px}.loading-subtitle{font-size:14px;color:var(--text2);margin-bottom:28px}.loading-steps{display:flex;flex-direction:column;gap:12px;text-align:left;max-width:280px;margin:0 auto}.loading-step{display:flex;align-items:center;gap:12px}.loading-dot{width:10px;height:10px;border-radius:50%;background:var(--surface3);flex-shrink:0;transition:background .3s}.loading-dot-active{background:var(--accent);animation:pulse 1s infinite}.loading-dot-done{background:var(--green)}@keyframes pulse{0%,to{opacity:1}50%{opacity:.4}}.loading-step-label{font-size:14px;color:var(--text3);transition:color .3s}.loading-step-label-active{color:var(--text)}.loading-step-label-done{color:var(--green)}.workspace{display:grid;grid-template-columns:1fr 380px;gap:20px;padding-bottom:48px}@media (max-width: 900px){.workspace{grid-template-columns:1fr}}.workspace-right{display:flex;flex-direction:column;gap:12px;position:sticky;top:80px;height:fit-content}.video-embed{background:#000;border-radius:var(--radius-lg);overflow:hidden;aspect-ratio:16/9;margin-bottom:16px}.video-embed-iframe{width:100%;height:100%;display:block;border:none}.video-embed-thumb{width:100%;height:100%;object-fit:cover;display:block}.video-embed-placeholder{width:100%;height:100%;display:flex;align-items:center;justify-content:center;background:var(--surface2);color:var(--text3);font-size:14px}.video-meta{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);padding:16px 20px;margin-bottom:16px}.video-meta-title{font-size:17px;font-weight:600;margin-bottom:10px;letter-spacing:-.3px;line-height:1.4}.video-meta-chips{display:flex;gap:14px;flex-wrap:wrap}.video-meta-chip{font-size:13px;color:var(--text2);display:flex;align-items:center;gap:5px}.tabbar{display:flex;gap:4px;background:var(--surface2);border-radius:var(--radius-sm);padding:4px;margin-bottom:16px}.tabbar-button{flex:1;padding:8px 4px;border:none;border-radius:6px;font-size:13px;font-weight:500;cursor:pointer;transition:all .2s;background:transparent;color:var(--text3)}.tabbar-button-active{background:var(--surface);color:var(--text);box-shadow:0 1px 3px #0000004d}.card{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);padding:18px 20px;margin-bottom:12px}.card-title{font-size:11px;font-weight:700;color:var(--text3);text-transform:uppercase;letter-spacing:.8px;margin-bottom:12px}.summary-text{font-size:15px;line-height:1.7;color:var(--text2)}.summary-text strong{color:var(--text);font-weight:500}.concepts-grid{display:flex;flex-wrap:wrap;gap:8px}.concept-chip{padding:6px 14px;background:var(--accent-bg);border:1px solid var(--accent-border);border-radius:100px;font-size:13px;color:var(--accent2);font-weight:500;cursor:pointer;transition:all .15s}.concept-chip:hover{background:#7c6af533;transform:scale(1.03)}.actions-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:8px}.action-btn{background:var(--surface2);border:1px solid var(--border);border-radius:var(--radius-sm);padding:12px 14px;cursor:pointer;display:flex;align-items:center;gap:10px;text-align:left;color:inherit;transition:background .2s}.action-btn:hover{background:var(--surface3)}.action-icon{width:32px;height:32px;border-radius:8px;display:flex;align-items:center;justify-content:center;font-size:15px;flex-shrink:0}.action-icon-green{background:#3ecf8e1a}.action-icon-purple{background:#7c6af51a}.action-icon-amber{background:#fbbf241a}.action-icon-red{background:#f871711a}.action-label{font-size:13px;font-weight:500;color:var(--text);margin-bottom:2px}.action-sub{font-size:12px;color:var(--text2)}.empty-state{color:var(--text2);padding:40px 20px;text-align:center;font-size:14px}.quiz-question{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);padding:18px 20px;margin-bottom:12px}.quiz-question-text{font-size:15px;font-weight:500;margin-bottom:14px;line-height:1.5}.quiz-options{display:flex;flex-direction:column;gap:8px}.quiz-option{padding:10px 14px;background:var(--surface2);border:1px solid 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var(--border);border-radius:100px;color:var(--text2);cursor:pointer;white-space:nowrap}.chat-window{flex:1;overflow-y:auto;padding:16px;display:flex;flex-direction:column;gap:12px;min-height:280px;max-height:440px}.msg{display:flex;gap:8px;align-items:flex-start}.msg-user{flex-direction:row-reverse}.msg-avatar{width:28px;height:28px;border-radius:50%;display:flex;align-items:center;justify-content:center;font-size:13px;flex-shrink:0}.msg-avatar-ai{background:var(--accent-bg)}.msg-avatar-user{background:var(--surface3)}.msg-bubble{max-width:82%;padding:10px 14px;font-size:14px;line-height:1.6;border-radius:12px}.msg-bubble-ai{background:var(--surface2);border:1px solid var(--border);color:var(--text);border-radius:4px 12px 12px}.msg-bubble-user{background:var(--accent);color:#fff;border-radius:12px 4px 12px 12px}.msg-line:not(:last-child){margin-bottom:4px}.typing-row{display:flex;gap:4px;align-items:center;padding:2px 0}.typing-dot{width:7px;height:7px;border-radius:50%;background:var(--text3);animation:bounce 1.2s infinite}.typing-dot:nth-child(2){animation-delay:.2s}.typing-dot:nth-child(3){animation-delay:.4s}@keyframes bounce{0%,60%,to{transform:none;opacity:.4}30%{transform:translateY(-5px);opacity:1}}.chat-input-row{display:flex;gap:8px;align-items:flex-end}.chat-input-textarea{flex:1;background:var(--surface2);border:1px solid var(--border2);border-radius:var(--radius-sm);color:var(--text);font-size:14px;padding:10px 14px;resize:none;outline:none;font-family:inherit;line-height:1.5;min-height:40px;max-height:120px}.chat-input-textarea:focus{border-color:var(--accent)}.chat-input-send{width:40px;height:40px;background:var(--accent);border:none;border-radius:var(--radius-sm);color:#fff;cursor:pointer;font-size:16px;display:flex;align-items:center;justify-content:center;flex-shrink:0;transition:opacity 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