:root{--agent-dark:#0b1a2b;--white:#fff;--boss-orange:#ff6a1a;--ink-900:#111827;--ink-700:#374151;--ink-500:#9ca3af;--ink-300:#d1d5db;--ink-100:#f3f4f6;--bg:var(--agent-dark);--surface:#122538;--surface-2:#1a3048;--border:#ffffff14;--border-strong:#ffffff29;--text:var(--white);--text-muted:var(--ink-500);--accent:var(--boss-orange);--text-tren-nen-sang:#1a1a1a;--muted-tren-nen-sang:#646b78;--cam-chu-tren-nen-sang:#c2410c;--sp-1:4px;--sp-2:8px;--sp-3:16px;--sp-4:24px;--sp-5:32px;--sp-6:48px;--sp-7:64px;--sp-8:96px;--radius-sm:6px;--radius-md:10px;--radius-lg:16px;--font-sans:"Inter", system-ui, -apple-system, "Segoe UI", Roboto, Arial, sans-serif;--font-mono:"Roboto Mono", ui-monospace, SFMono-Regular, Menlo, monospace}*{box-sizing:border-box}html,body{font-family:var(--font-sans);background:var(--bg);color:var(--text);-webkit-font-smoothing:antialiased;margin:0;padding:0;font-size:16px;line-height:1.6}html.theme-light{--bg:#faf6ee;--surface:#fff;--surface-2:#f5f0e5;--border:#0b1a2b1a;--border-strong:#0b1a2b33;--text:#1a1a1a;--text-muted:#6b6f76}html.theme-light body{background:var(--bg);color:var(--text)}html.theme-light .alert-info{color:var(--text);background:#fff6e6;border-color:#ff6a1a4d}html.theme-light .alert-success{color:#14532d;background:#e8f5e9;border-color:#22c55e66}html.theme-light .alert-success a{color:inherit;font-weight:600;text-decoration:underline}html.theme-light .alert-error{color:#7f1d1d;background:#feecec;border-color:#ef444466}html.theme-light .card{background:var(--surface);border:1px solid var(--border);box-shadow:0 2px 8px #0b1a2b0a}html.theme-light .lesson-card{background:var(--surface);border:1px solid var(--border)}html.theme-light .lesson-card.locked{background:var(--surface-2)}html.theme-light .lesson-card.locked .num,html.theme-light .lesson-card.locked .stage{color:var(--muted-tren-nen-sang)}html.theme-light .text-accent{color:var(--cam-chu-tren-nen-sang)}html.theme-light .lesson-card.done{background:var(--surface)}html.theme-light .progress-bar{background:#0b1a2b14}html.theme-light pre.copy-block{color:#f3f4f6;background:#1a1f2e;border-color:#0b1a2b33}html.theme-light .btn-ghost{color:var(--text);border-color:var(--border-strong)}html.theme-light .btn-ghost:hover{border-color:var(--text)}html.theme-light .field input[type=email],html.theme-light .field input[type=text],html.theme-light .field input[type=tel],html.theme-light .field input[type=password],html.theme-light .field textarea,html.theme-light .field select{background:var(--surface);color:var(--text);border-color:var(--border-strong)}html.theme-light .site-footer{color:var(--text-muted);border-top-color:var(--border)}.tren-nen-sang{color:var(--text-tren-nen-sang)}.tren-nen-sang .muted,.tren-nen-sang .phu{color:var(--muted-tren-nen-sang)}a{color:var(--accent);text-decoration:none}a:hover{text-decoration:underline}h1{letter-spacing:-.03em;margin:0 0 var(--sp-4);font-size:clamp(32px,5vw,48px);font-weight:700;line-height:1.15}h2{letter-spacing:-.02em;margin:0 0 var(--sp-3);font-size:clamp(24px,3.5vw,32px);font-weight:600;line-height:1.2}h3{margin:0 0 var(--sp-3);font-size:clamp(18px,2.5vw,22px);font-weight:600;line-height:1.3}p{margin:0 0 var(--sp-3)}.shell{flex-direction:column;min-height:100vh;display:flex}.container{width:100%;max-width:1100px;padding:0 var(--sp-4);margin:0 auto}.container-narrow{width:100%;max-width:560px;padding:0 var(--sp-4);margin:0 auto}.site-header{padding:var(--sp-3) 0;background:#0b1a2b;border-bottom:1px solid #ffffff14}.site-header .brand{align-items:center;gap:var(--sp-3);letter-spacing:.02em;color:#fff;font-weight:700;text-decoration:none;display:inline-flex}.site-header .brand:hover{text-decoration:none}.site-header .brand .brand-logo{width:auto;height:32px;display:block}.site-header .brand .brand-sub{color:#ffffff8c;letter-spacing:.04em;text-transform:uppercase;font-size:12px;font-weight:500}@media (width<=480px){.site-header .brand .brand-logo{height:28px}.site-header .brand .brand-sub{font-size:11px}}.card{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius-lg);padding:var(--sp-5)}.field{margin-bottom:var(--sp-4)}.field label{color:var(--text-muted);margin-bottom:var(--sp-2);cursor:pointer;font-size:14px;font-weight:500;display:block}.field input[type=email],.field input[type=text],.field input[type=tel],.field input[type=password],.field textarea,.field select{background:var(--surface-2);border:1px solid var(--border-strong);border-radius:var(--radius-md);width:100%;color:var(--text);box-sizing:border-box;outline:none;padding:12px 14px;font-family:inherit;font-size:16px;line-height:1.6;transition:border-color .15s}.field textarea{resize:vertical;min-height:88px}.field input::placeholder,.field textarea::placeholder{color:var(--text-muted);opacity:1}.field input:focus,.field textarea:focus,.field select:focus{border-color:var(--accent)}.btn{justify-content:center;align-items:center;gap:var(--sp-2);border-radius:var(--radius-md);cursor:pointer;border:1px solid #0000;padding:12px 24px;font-family:inherit;font-size:15px;font-weight:600;text-decoration:none;transition:transform 50ms,opacity .15s;display:inline-flex}.btn:active{transform:translateY(1px)}.btn:disabled{opacity:.5;cursor:not-allowed}.btn-primary{background:var(--accent);color:var(--chu-tren-accent,#050d16)}.btn-primary:hover{opacity:.92}.btn-primary[style*="9ca3af"],.btn-primary[style*="156, 163, 175"]{color:#050d16}.btn-ghost{color:var(--text);border-color:var(--border-strong);background:0 0}.btn-ghost:hover{border-color:var(--text)}.btn-block{width:100%}.alert{padding:var(--sp-3) var(--sp-4);border-radius:var(--radius-md);border:1px solid var(--border);margin-bottom:var(--sp-4);font-size:14px}.alert-success{background:#22c55e14;border-color:#22c55e66}.alert-error{background:#ef444414;border-color:#ef444466}.alert-info{border-color:var(--border-strong);background:var(--surface-2)}.text-muted{color:var(--text-muted)}.text-accent{color:var(--accent)}.text-center{text-align:center}.mt-4{margin-top:var(--sp-4)}.mt-5{margin-top:var(--sp-5)}.mb-3{margin-bottom:var(--sp-3)}.mb-4{margin-bottom:var(--sp-4)}.mb-5{margin-bottom:var(--sp-5)}.flex{display:flex}.gap-3{gap:var(--sp-3)}.gap-4{gap:var(--sp-4)}pre.copy-block{border:1px solid var(--border-strong);border-radius:var(--radius-md);padding:var(--sp-4);font-family:var(--font-mono);color:var(--ink-100);white-space:pre-wrap;word-break:break-all;margin:0 0 var(--sp-3);background:#050d18;font-size:13px;line-height:1.5;overflow-x:auto}.lesson-grid{gap:var(--sp-3);grid-template-columns:repeat(auto-fill,minmax(180px,1fr));display:grid}.lesson-card{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius-md);padding:var(--sp-4);min-height:140px;color:inherit;flex-direction:column;justify-content:space-between;text-decoration:none;transition:border-color .15s,transform .1s,box-shadow .15s,background .15s;display:flex;position:relative}.lesson-card,.lesson-card *{text-decoration:none!important}a.lesson-card:hover{border-color:var(--accent);transform:translateY(-2px);box-shadow:0 4px 12px #ff6a1a1f}.badge-section{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius-md);padding:var(--sp-4)}.badge-grid{gap:var(--sp-3);grid-template-columns:repeat(auto-fit,minmax(140px,1fr));display:grid}.badge-card{text-align:center;padding:var(--sp-3);border-radius:var(--radius-md);border:1px solid var(--border);background:#fff9;transition:opacity .2s,transform .15s}.badge-card img{object-fit:contain;width:96px;height:96px;margin:0 auto var(--sp-2);display:block}.badge-card .badge-name{margin-bottom:var(--sp-1);font-size:14px;font-weight:600}.badge-card .badge-status{color:var(--text-muted);font-size:12px}.badge-card.locked img{opacity:.4;filter:grayscale(.6)}.badge-card.earned{border-color:var(--accent);box-shadow:0 0 0 1px var(--accent)}.badge-card.earned .badge-status{color:var(--cam-chu-tren-nen-sang);font-weight:600}@media (width<=480px){.badge-grid{grid-template-columns:repeat(2,1fr)}.badge-card img{width:72px;height:72px}}.lesson-card .num{font-family:var(--font-mono);color:var(--text-muted);margin-bottom:var(--sp-2);font-size:12px}.lesson-card .title{font-size:15px;font-weight:600;line-height:1.3}.lesson-card .stage{text-transform:uppercase;letter-spacing:.05em;color:var(--text-muted);margin-top:var(--sp-3);font-size:11px}.lesson-card.locked{border-style:dashed}.lesson-card.locked:after{content:"🔒";top:var(--sp-3);right:var(--sp-3);opacity:.7;font-size:14px;position:absolute}.lesson-card.locked.cho-nop-bai:after{content:"📝";opacity:1}.lesson-card.locked.cho-nop-bai .stage{color:var(--accent);text-transform:none;letter-spacing:0;font-size:12px}.lesson-card.open{border-color:var(--accent);box-shadow:0 0 0 1px var(--accent)}.lesson-card.done{border-style:dashed}.lesson-card.done:after{content:"✓";top:var(--sp-3);right:var(--sp-3);color:var(--accent);font-weight:700;position:absolute}.bai0-callout{color:#fff;border-radius:var(--radius-lg);padding:var(--sp-5);margin-bottom:var(--sp-5);gap:var(--sp-3);background:linear-gradient(135deg,#ff6a1a 0%,#e8550a 100%);flex-direction:column;display:flex;box-shadow:0 8px 24px #ff6a1a40}.bai0-callout .bai0-icon{font-size:32px;line-height:1}.bai0-callout h2{color:#fff;letter-spacing:-.01em;margin:0;font-size:clamp(20px,3.5vw,26px);font-weight:700}.bai0-callout p{color:#ffffffeb;margin:0;font-size:15px;line-height:1.5}.bai0-callout .bai0-cta{align-items:center;gap:var(--sp-2);color:#0b1a2b;border-radius:var(--radius-md);margin-top:var(--sp-2);background:#fff;align-self:flex-start;padding:14px 28px;font-size:16px;font-weight:700;text-decoration:none;transition:transform 50ms,box-shadow .15s;display:inline-flex}.bai0-callout .bai0-cta:hover{text-decoration:none;box-shadow:0 4px 12px #0000002e}.bai0-callout .bai0-cta:active{transform:translateY(1px)}@media (width<=480px){.bai0-callout{padding:var(--sp-4)}.bai0-callout .bai0-cta{justify-content:center;width:100%}}.progress-bar{background:var(--surface-2);border-radius:999px;width:100%;height:8px;overflow:hidden}.progress-bar>span{background:var(--accent);height:100%;transition:width .4s;display:block}.step{gap:var(--sp-3);margin-bottom:var(--sp-4);display:flex}.step-num{background:var(--accent);width:32px;height:32px;color:var(--white);border-radius:50%;flex-shrink:0;justify-content:center;align-items:center;font-size:14px;font-weight:700;display:flex}.step-body{padding-top:4px}.step-body h3{margin:0 0 var(--sp-2)}.site-footer{padding:var(--sp-5) 0;border-top:1px solid var(--border);color:var(--text-muted);text-align:center;margin-top:auto;font-size:13px}html.khung-giay body{background:var(--agent-dark)}html.khung-giay .site-footer{--text-muted:#ffffff9e;color:var(--text-muted);border-top-color:#ffffff14}html.khung-giay .site-footer strong{color:#fff}.khung-giay-body{flex:1;align-items:flex-start;width:100%;max-width:1280px;margin:0 auto;display:flex}.thanh-ben{color:#fff;border-right:1px solid #ffffff14;flex-shrink:0;align-self:stretch;width:280px}.thanh-ben:not(:has(.tb)){display:none}.khung-giay-main{flex:1;justify-content:center;min-width:0;padding:48px 32px 96px;display:flex}.to-giay{--text:#0b1a2b;--text-muted:#4b5563;--border:#0b1a2b1a;--border-strong:#0b1a2b2e;width:100%;max-width:760px;color:var(--text);border-radius:var(--radius-lg);background:#fbfaf7;padding:48px 56px 56px;position:relative;box-shadow:0 24px 70px #00000073,0 2px 10px #0000004d,0 0 0 1px #0003}.to-giay:before{content:"";border-radius:var(--radius-lg) var(--radius-lg) 0 0;background:var(--accent);height:3px;position:absolute;top:0;left:0;right:0}.to-giay h1{letter-spacing:-.01em;color:var(--text);margin-bottom:var(--sp-3);font-size:clamp(26px,3.4vw,34px);font-weight:800;line-height:1.2}.to-giay :is(p,li,td,div,span,label)>a:where(:not([class*=btn])){color:var(--cam-chu-tren-nen-sang)}.to-giay>.container-narrow,.to-giay>.container{max-width:none!important;padding:0!important}html.khung-giay .to-giay>.container-narrow>.card{box-shadow:none;background:0 0;border:0;border-radius:0;padding:0!important}html.khung-giay .to-giay .lesson-body .ls-block{border:0;border-top:1px solid var(--border);box-shadow:none;padding:var(--sp-4) 0 0;background:0 0;border-radius:0}html.khung-giay .to-giay .lesson-body .ls-block:first-child{border-top:0;padding-top:0}.to-giay .btn-primary:disabled{cursor:not-allowed;opacity:1!important;color:#4b5563!important;background:#dde1e6!important;border-color:#dde1e6!important}.to-giay input[type=text],.to-giay input[type=email],.to-giay input[type=tel],.to-giay input[type=url],.to-giay textarea,.to-giay select{font-size:16px!important}@media (width<=900px){.thanh-ben{display:none}}@media (width<=640px){.khung-giay-main{padding:0}.to-giay{box-shadow:none;border-radius:0;padding:28px 18px 40px}}@media print{html.khung-giay body{color:#0b1a2b;background:#fff}html.khung-giay-ngan-keo .site-header,html.khung-giay .site-footer,.thanh-ben{display:none!important}.khung-giay-main{padding:0}.to-giay{max-width:none;box-shadow:none;padding:0}.to-giay:before{display:none}}html.khung-giay-ngan-keo .site-header .brand .brand-sub,html.khu-hoc-toi .site-header .brand .brand-sub{color:#ff9c66;letter-spacing:.06em;border:1px solid #ff6a1a73;border-radius:9999px;padding:0 12px;font-weight:700;line-height:24px}html.khung-giay-ngan-keo .site-header .header-link,html.khu-hoc-toi .site-header .header-link{color:#ffffffc7;min-height:44px;padding:0 12px;font-size:14px}html.khung-giay-ngan-keo .site-header .header-link:hover,html.khu-hoc-toi .site-header .header-link:hover{color:#fff;background:#ffffff0f}.site-header .hl-svg,html.khung-giay-ngan-keo .site-header .hl-emoji,html.khu-hoc-toi .site-header .hl-emoji{display:none}html.khung-giay-ngan-keo .site-header .hl-svg,html.khu-hoc-toi .site-header .hl-svg{vertical-align:-3px;flex:none;width:18px;height:18px;display:inline-block}html.khung-giay-ngan-keo .site-header .header-link,html.khu-hoc-toi .site-header .header-link{align-items:center;gap:6px;display:inline-flex}.site-footer .footer-logo{display:none}html.khung-giay-ngan-keo .site-footer .footer-logo,html.khu-hoc-toi .site-footer .footer-logo{width:auto;height:32px;margin:0 auto 12px;display:block}html.khung-giay-ngan-keo .site-header,html.khu-hoc-toi .site-header{z-index:50;padding:0;position:sticky;top:0}html.khung-giay-ngan-keo .site-header .header-row,html.khu-hoc-toi .site-header .header-row{flex-wrap:nowrap;max-width:1280px;height:64px;padding:0 24px}html.khung-giay-ngan-keo .site-header .header-nav,html.khu-hoc-toi .site-header .header-nav{margin-left:auto}html.khung-giay-ngan-keo .site-footer,html.khung-giay:has(.vao-ra) .site-footer{margin-top:96px;padding:32px 24px;line-height:1.7}html.khu-hoc-toi{--text-muted:#b6c6d8}html.khu-hoc-toi main>.container{max-width:1280px;padding:0 24px}@media (width<=900px){html.khu-hoc-toi main>.container{padding:0 16px}}html.khung-giay-ngan-keo #b2b-announce-banner,html.khu-hoc-toi #b2b-announce-banner{background:#0f1f38;border-bottom:1px solid #ffffff1f}html.khung-giay-ngan-keo #b2b-announce-banner .b2b-announce-text,html.khu-hoc-toi #b2b-announce-banner .b2b-announce-text{color:#ffffffdb}html.khung-giay-ngan-keo #b2b-announce-banner .b2b-announce-text strong,html.khu-hoc-toi #b2b-announce-banner .b2b-announce-text strong{color:#fff}html.khung-giay-ngan-keo #b2b-announce-banner .btn-b2b-announce-do,html.khu-hoc-toi #b2b-announce-banner .btn-b2b-announce-do{color:#ff9c66;background:0 0;border:1px solid #ff6a1a;align-items:center;min-height:44px;padding:0 14px;display:inline-flex}html.khung-giay-ngan-keo #b2b-announce-banner .btn-b2b-announce-do:hover,html.khu-hoc-toi #b2b-announce-banner .btn-b2b-announce-do:hover{color:#fff;background:#ff6a1a24}html.khung-giay-ngan-keo #b2b-announce-banner .btn-b2b-announce-done,html.khu-hoc-toi #b2b-announce-banner .btn-b2b-announce-done{color:#fff;background:0 0;border:1px solid #ffffff47;min-height:44px;padding:0 14px}html.khung-giay-ngan-keo #b2b-announce-banner .btn-b2b-announce-done:hover,html.khu-hoc-toi #b2b-announce-banner .btn-b2b-announce-done:hover{background:#ffffff14}html.khung-giay-ngan-keo #b2b-announce-banner{display:none}@media (width<=900px){html.khung-giay-ngan-keo .ban-quyen-ab{margin-bottom:8px;font-size:12px;line-height:1.45}html.khung-giay-ngan-keo .ngtt-nut{min-height:0;padding:2px}html.khung-giay-ngan-keo .ngtt-nut span{clip:rect(0 0 0 0);white-space:nowrap;width:1px;height:1px;position:absolute;overflow:hidden}}html.khung-giay .to-giay:has(.vao-hep){max-width:560px}html.khung-giay .to-giay:has(.vao-vua){max-width:640px}html.khung-giay .to-giay:has(.vao-rong){max-width:720px}.to-giay .vao-ra h1{font-size:22px;font-weight:700;line-height:1.3}.to-giay .vao-ra .the-logo{color:#fff;letter-spacing:.01em;background:#0b1a2b;border-radius:8px;align-items:center;gap:8px;padding:12px 16px;font-size:14px;font-weight:700;display:inline-flex}.to-giay .vao-ra .the-logo img{width:auto;max-width:min(260px,100%);height:24px;display:block}.vao-ra .the-logo b{color:#ff7a2a;font-weight:700}.to-giay .vao-ra .the-logo-hang{justify-content:center;margin-bottom:24px;display:flex}.to-giay #ob-root>.card{box-shadow:none;background:0 0;border:0;border-radius:0;padding:0!important}.to-giay #ob-root h2{font-size:22px;font-weight:700;line-height:1.3}.to-giay .vao-kid{background:#050d16;border-radius:50%;width:96px;height:96px;margin:0 auto 24px;overflow:hidden;box-shadow:0 0 0 1px #ff6a1a66,0 8px 24px #0b1a2b40}.to-giay .vao-kid img{object-fit:cover;width:100%;height:100%;display:block}html.khung-giay-ngan-keo .thanh-ben{align-self:stretch;padding-bottom:72px}html.khung-giay-ngan-keo .thanh-ben .tb.tb-abs{max-height:calc(100vh - 64px);padding:24px 16px 96px 24px;top:64px}.thanh-ben .tb-abs .tb-ve{align-items:center;min-height:44px;margin-bottom:0;font-size:13px;display:inline-flex}.thanh-ben .tb-abs .tb-ten{font-size:16px;font-weight:700}.thanh-ben .tb-abs .tb-chang-ten{font-size:12px}.thanh-ben .tb-abs .tbd{min-height:44px;padding:12px}.thanh-ben .tb-abs .tbd-so{min-width:24px}.khung-giay-mo-ds{display:none}.khung-giay-mo-ds[hidden]{display:none!important}.khung-giay-ngan-nen{z-index:1000;background:#050d16b3;display:none;position:fixed;inset:0}.khung-giay-ngan{z-index:1001;visibility:hidden;color:#fff;background:#0b1a2b;border-right:1px solid #ffffff1f;width:min(320px,88vw);position:fixed;top:0;bottom:0;left:0;overflow-y:auto;transform:translate(-100%)}.khung-giay-ngan .thanh-ben{border-right:0;width:auto;display:block}.khung-giay-ngan .thanh-ben .tb.tb-abs{max-height:none;padding:8px 16px 48px 24px;position:static;overflow:visible}.khung-giay-ngan-dau{justify-content:space-between;align-items:center;padding:12px 16px 0 24px;font-size:14px;font-weight:700;display:flex}.khung-giay-ngan-dau button{color:#fff;cursor:pointer;background:0 0;border:1px solid #fff3;border-radius:6px;min-width:44px;min-height:44px;font-size:16px}body.khung-giay-mo-ngan .khung-giay-ngan{visibility:visible;transform:none}body.khung-giay-mo-ngan .khung-giay-ngan-nen{display:block}@media (prefers-reduced-motion:no-preference){.khung-giay-ngan{transition:transform .2s,visibility .2s}}@media (width<=900px){.khung-giay-mo-ds{z-index:40;background:#0b1a2b;border-bottom:1px solid #ffffff14;align-items:center;gap:12px;padding:8px 16px;display:flex;position:sticky;top:64px}.khung-giay-mo-ds button{color:#fff;cursor:pointer;background:#0f1f38;border:1px solid #ffffff29;border-radius:6px;align-items:center;gap:8px;min-height:44px;padding:6px 12px;font-family:inherit;font-size:14px;font-weight:600;display:inline-flex}.khung-giay-mo-ds .khung-giay-vi-tri{color:#ffffffc7;font-size:13px}}@media (width<=640px){html.khung-giay-ngan-keo .site-header .header-link,html.khu-hoc-toi .site-header .header-link{justify-content:center;min-width:44px;padding:0 8px}html.khung-giay-ngan-keo .site-header .header-link .chu-dai,html.khu-hoc-toi .site-header .header-link .chu-dai{clip:rect(0 0 0 0);white-space:nowrap;width:1px;height:1px;position:absolute;overflow:hidden}html.khung-giay-ngan-keo .site-header .header-row,html.khu-hoc-toi .site-header .header-row{gap:8px;padding:0 16px}}.lesson-body{margin-top:var(--sp-4);gap:var(--sp-4);color:var(--text);flex-direction:column;font-size:15.5px;line-height:1.75;display:flex}.lesson-body .ls-block{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius-lg);padding:var(--sp-4) var(--sp-5);box-shadow:0 2px 8px #0b1a2b0a}.lesson-body .ls-block>:first-child{margin-top:0}.lesson-body .ls-block>:last-child{margin-bottom:0}.lesson-body h2{color:var(--text);margin:0 0 var(--sp-3);border-left:4px solid var(--accent);padding-left:14px;font-size:21px;font-weight:700;line-height:1.3}.lesson-body h3{color:var(--text);margin:var(--sp-4) 0 var(--sp-2);font-size:17px;font-weight:600}.lesson-body h3:first-child{margin-top:0}.lesson-body h4{color:var(--accent);margin:var(--sp-3) 0 var(--sp-1);font-size:15px;font-weight:700}.lesson-body p{margin:0 0 var(--sp-3)}.lesson-body p:last-child{margin-bottom:0}.lesson-body strong{font-weight:700}.lesson-body a{color:var(--cam-chu-tren-nen-sang);text-underline-offset:2px;font-weight:600;text-decoration:underline}.lesson-body ul,.lesson-body ol{margin:0 0 var(--sp-3);padding-left:24px}.lesson-body li{margin-bottom:var(--sp-2);line-height:1.7}.lesson-body li:last-child{margin-bottom:0}.lesson-body ul{padding-left:6px;list-style:none}.lesson-body ul>li{padding-left:22px;position:relative}.lesson-body ul>li:before{content:"";background:var(--accent);border-radius:50%;width:7px;height:7px;position:absolute;top:.62em;left:4px}.lesson-body ol{list-style:decimal}.lesson-body ol li::marker{color:var(--cam-chu-tren-nen-sang);font-weight:700}.lesson-body blockquote{margin:var(--sp-3) 0;border:2px solid var(--accent);border-radius:var(--radius-md);color:#7c2d12;background:linear-gradient(135deg,#fff7ed 0%,#fef3c7 100%);padding:14px 18px;font-style:normal}.lesson-body blockquote>:first-child{margin-top:0}.lesson-body blockquote>:last-child{margin-bottom:0}.lesson-body blockquote p{color:#7c2d12}.lesson-body blockquote strong,.lesson-body blockquote a{color:#c2410c}.lesson-body blockquote ul>li:before{background:#c2410c}.lesson-body table{border-collapse:collapse;width:100%;margin:var(--sp-3) 0;font-size:14.5px}.lesson-body th,.lesson-body td{border:1px solid var(--border-strong);text-align:left;vertical-align:top;padding:10px 14px}.lesson-body thead th{background:var(--surface-2);color:var(--text);font-weight:700}.lesson-body tbody tr:nth-child(2n){background:#ff6a1a09}.lesson-body img{border-radius:var(--radius-md);border:1px solid var(--border);max-width:100%;height:auto;margin:var(--sp-3) 0;display:block}.lesson-body code{background:var(--surface-2);border-radius:var(--radius-sm);font-family:var(--font-mono);color:var(--text);overflow-wrap:anywhere;padding:2px 6px;font-size:13.5px}.lesson-body pre{color:#f3f4f6;padding:var(--sp-3) var(--sp-4);border-radius:var(--radius-md);margin:var(--sp-3) 0;background:#1a1f2e;overflow-x:auto}.lesson-body pre code{color:inherit;background:0 0;padding:0}.lesson-body hr{border:0;border-top:1px solid var(--border);margin:var(--sp-4) 0}.lesson-body .wg-agent-setup,.lesson-body .wg-quiz{margin:var(--sp-2) 0 0}@media (width<=600px){.lesson-body{font-size:15px}.lesson-body .ls-block{padding:var(--sp-3) var(--sp-4)}.lesson-body h2{font-size:19px}}.lesson-body.ls-gated .ls-block-hidden,.lesson-body[data-hien-het="1"] .ls-gate-btn-wrap,.lesson-body[data-hien-het="1"] .ls-gate-progress{display:none}.lesson-body .ls-gate-progress{align-items:center;gap:var(--sp-3);margin-bottom:var(--sp-4);display:flex}.lesson-body .ls-gate-progress-track{background:var(--border);border-radius:999px;flex:1;height:4px;overflow:hidden}.lesson-body .ls-gate-progress-fill{background:var(--accent);border-radius:999px;height:100%;transition:width .4s}.lesson-body .ls-gate-progress-label{color:var(--muted-tren-nen-sang);white-space:nowrap;font-variant-numeric:tabular-nums;font-size:12px;font-weight:600}.lesson-body .ls-gate-btn-wrap{margin-top:var(--sp-4);padding-top:var(--sp-3);border-top:1px solid var(--border);justify-content:flex-end;display:flex}.lesson-body .ls-gate-btn{min-width:140px}.lesson-body .ls-gate-btn:disabled{opacity:.5;cursor:default}.lesson-body .ls-gate-btn-locked{cursor:not-allowed;opacity:.55}.lesson-body .wg-noi-he-thong{margin:var(--sp-4) 0;padding:var(--sp-4);border:1px solid var(--border);border-radius:var(--radius-md);background:var(--surface-2)}.lesson-body .wg-nht-status{color:var(--muted-tren-nen-sang)}.lesson-body .wg-noi-he-thong.wg-nht-connected{background:#2e7d321a;border-color:#2e7d32}.lesson-body .wg-noi-he-thong.wg-nht-connected .wg-nht-status{color:var(--text)}.lesson-body .wg-noi-he-thong.wg-nht-connected .wg-nht-check{color:#fff;cursor:default;opacity:1;background:#2e7d32;border-color:#2e7d32}.lesson-body .wg-ho-so-day-du{margin:var(--sp-4) 0;padding:var(--sp-4);border:1px solid var(--border);border-radius:var(--radius-md);background:var(--surface-2)}.lesson-body .wg-hsdd-status{color:var(--muted-tren-nen-sang)}.lesson-body .wg-ho-so-day-du.wg-hsdd-du{background:#2e7d321a;border-color:#2e7d32}.lesson-body .wg-ho-so-day-du.wg-hsdd-du .wg-hsdd-status{color:var(--text)}.lesson-body .wg-ho-so-day-du.wg-hsdd-du .wg-hsdd-check{color:#fff;cursor:default;opacity:1;background:#2e7d32;border-color:#2e7d32}.lesson-body .wg-cong-hoan-thanh{margin:var(--sp-4) 0;padding:var(--sp-4);border:1px solid var(--border);border-radius:var(--radius-md);background:var(--surface-2)}.lesson-body .wg-cht-status{color:var(--muted-tren-nen-sang)}.lesson-body .wg-cong-hoan-thanh.wg-cht-done{background:#2e7d321a;border-color:#2e7d32}.lesson-body .wg-cong-hoan-thanh.wg-cht-done .wg-cht-status{color:var(--text)}.lesson-body .wg-cong-hoan-thanh.wg-cht-done .wg-cht-btn{color:#fff;cursor:default;background:#2e7d32;border-color:#2e7d32}.lesson-body .wg-nop-bao-cao{margin:var(--sp-4) 0;padding:var(--sp-4);border:1px solid var(--border);border-radius:var(--radius-md);background:var(--surface-2)}.lesson-body .wg-nbc-input{box-sizing:border-box;width:100%;padding:var(--sp-3);border:1px solid var(--border-strong);border-radius:var(--radius-md);background:var(--surface);color:var(--text);resize:vertical;margin-bottom:var(--sp-3);font-family:inherit;font-size:14px;line-height:1.6}.lesson-body .wg-nbc-status{color:var(--muted-tren-nen-sang)}.lesson-body .wg-nop-bao-cao.wg-nbc-done{background:#2e7d321a;border-color:#2e7d32}.lesson-body .wg-nop-bao-cao.wg-nbc-done .wg-nbc-status{color:var(--text)}.lesson-body .wg-nop-bao-cao.wg-nbc-done .wg-nbc-btn{color:#fff;cursor:default;background:#2e7d32;border-color:#2e7d32}@keyframes ls-reveal{0%{opacity:0;transform:translateY(10px)}to{opacity:1;transform:translateY(0)}}.lesson-body .ls-block:not(.ls-block-hidden){animation:.3s both ls-reveal}.lesson-body .ls-flashcard-group{gap:var(--sp-3);margin:var(--sp-3) 0;grid-template-columns:repeat(auto-fill,minmax(220px,1fr));display:grid}.lesson-body .ls-fc{perspective:1000px;cursor:pointer;border-radius:var(--radius-md);height:100%;min-height:160px;position:relative}.lesson-body .ls-fc-js-ready .ls-fc-inner{transform-style:preserve-3d;width:100%;height:100%;transition:transform .55s cubic-bezier(.4,.1,.2,1);display:grid}.lesson-body .ls-fc-js-ready.ls-fc-flipped .ls-fc-inner{transform:rotateY(180deg)}.lesson-body .ls-fc-front,.lesson-body .ls-fc-back{border-radius:var(--radius-md);padding:var(--sp-4) var(--sp-3);text-align:center;flex-direction:column;justify-content:center;align-items:center;min-height:160px;display:flex}.lesson-body .ls-fc-front{background:var(--surface-2);border:1px solid var(--border-strong);color:var(--text)}.lesson-body .ls-fc-back{background:var(--surface);border:1px solid var(--accent);color:var(--text);margin-top:var(--sp-2)}.lesson-body .ls-fc-js-ready .ls-fc-front,.lesson-body .ls-fc-js-ready .ls-fc-back{backface-visibility:hidden;grid-area:1/1;height:100%;margin-top:0;position:relative;overflow-y:auto}.lesson-body .ls-fc-js-ready .ls-fc-back{transform:rotateY(180deg)}.lesson-body .ls-fc-front-text{font-size:15px;font-weight:600;line-height:1.45}.lesson-body .ls-fc-hint{letter-spacing:1px;text-transform:uppercase;color:var(--muted-tren-nen-sang);margin-top:var(--sp-2);font-size:11px;font-weight:700;display:block}.lesson-body .ls-fc:not(.ls-fc-js-ready) .ls-fc-hint{display:none}.lesson-body .ls-fc-back-label{letter-spacing:1.4px;text-transform:uppercase;color:var(--accent);margin-bottom:var(--sp-2);font-size:11px;font-weight:800;display:block}html.khung-giay .lesson-body .ls-fc-back-label{color:#c2410c}html.khung-giay-ngan-keo .lesson-body pre.ls-pre-gon:not(.ls-pre-mo){max-height:220px;overflow:hidden}html.khung-giay-ngan-keo .lesson-body pre.ls-pre-gon.ls-pre-cat:not(.ls-pre-mo){-webkit-mask-image:linear-gradient(#000 calc(100% - 56px),#0000);mask-image:linear-gradient(#000 calc(100% - 56px),#0000)}html.khung-giay-ngan-keo .lesson-body pre.ls-pre-gon{white-space:pre-wrap;overflow-wrap:anywhere}html.khung-giay-ngan-keo .lesson-body .ls-pre-xem{width:fit-content;min-height:44px;color:var(--text);border:2px solid var(--text);justify-content:center;align-items:center;margin:8px auto;padding:8px 18px;font-size:15px;font-weight:600;display:flex}html.khung-giay-ngan-keo .lesson-body .ls-pre-xem[hidden]{display:none}.lesson-body .ls-fc-back-text{font-size:14px;line-height:1.6}.lesson-body .ls-fc-noscript,.lesson-body .ls-fc-js-ready .ls-fc-noscript{display:none}.lesson-body .ls-accordion{border:1px solid var(--border);border-radius:var(--radius-md);margin:var(--sp-3) 0;overflow:hidden}.lesson-body .ls-acc-item{border-bottom:1px solid var(--border)}.lesson-body .ls-acc-item:last-child{border-bottom:none}.lesson-body .ls-acc-head{justify-content:space-between;align-items:center;gap:var(--sp-3);background:var(--surface);width:100%;padding:var(--sp-3) var(--sp-4);cursor:pointer;text-align:left;font-family:var(--font-sans);color:var(--text);border:none;font-size:15px;font-weight:600;transition:background .15s;display:flex}.lesson-body .ls-acc-head:hover{background:var(--surface-2)}.lesson-body .ls-acc-title{flex:1}.lesson-body .ls-acc-arrow{color:var(--muted-tren-nen-sang);flex-shrink:0;font-size:12px;transition:transform .3s}.lesson-body .ls-acc-js-ready .ls-acc-item.ls-acc-open .ls-acc-arrow{color:var(--accent);transform:rotate(180deg)}.lesson-body .ls-acc-body{padding:var(--sp-2) var(--sp-4) var(--sp-3);background:var(--surface);color:var(--text);font-size:14.5px;line-height:1.7}.lesson-body .ls-acc-body>:first-child{margin-top:0}.lesson-body .ls-acc-body>:last-child{margin-bottom:0}.lesson-body .ls-acc-js-ready .ls-acc-body{max-height:0;padding-top:0;padding-bottom:0;transition:max-height .4s,padding .2s;overflow:hidden}.lesson-body .ls-acc-js-ready .ls-acc-item.ls-acc-open .ls-acc-body{max-height:5000px;padding:var(--sp-2) var(--sp-4) var(--sp-3)}.lesson-body .ls-tabs{border:1px solid var(--border);border-radius:var(--radius-md);margin:var(--sp-3) 0;overflow:hidden}.lesson-body .ls-tab-nav{border-bottom:1px solid var(--border);background:var(--surface);display:flex;overflow-x:auto}.lesson-body .ls-tab-btn{padding:var(--sp-2) var(--sp-4);font-family:var(--font-sans);color:var(--muted-tren-nen-sang);cursor:pointer;background:0 0;border:none;border-bottom:3px solid #0000;flex-shrink:0;font-size:14px;font-weight:600;transition:color .15s,border-color .15s}.lesson-body .ls-tab-btn:hover{color:var(--text)}.lesson-body .ls-tab-btn.ls-tab-active{color:var(--accent);border-bottom-color:var(--accent)}.lesson-body .ls-tab-body{background:var(--surface)}.lesson-body .ls-tab-panel{padding:var(--sp-4);color:var(--text);font-size:14.5px;line-height:1.7}.lesson-body .ls-tab-panel>:first-child{margin-top:0}.lesson-body .ls-tab-panel>:last-child{margin-bottom:0}.lesson-body .ls-tab-panel+.ls-tab-panel{border-top:1px solid var(--border)}.lesson-body .ls-tabs-js-ready .ls-tab-panel{display:none}.lesson-body .ls-tabs-js-ready .ls-tab-panel.ls-tab-panel-active{animation:.3s lsTabFade;display:block}.lesson-body .ls-tabs-js-ready .ls-tab-panel+.ls-tab-panel{border-top:none}@keyframes lsTabFade{0%{opacity:0;transform:translateY(6px)}to{opacity:1;transform:translateY(0)}}.lesson-body .ls-steps{margin:var(--sp-3) 0;flex-direction:column;display:flex}.lesson-body .ls-step{gap:var(--sp-3);align-items:flex-start;display:flex}.lesson-body .ls-step-track{flex-direction:column;flex-shrink:0;align-items:center;display:flex}.lesson-body .ls-step-dot{background:var(--accent);color:#fff;border-radius:50%;flex-shrink:0;justify-content:center;align-items:center;width:32px;height:32px;font-size:13px;font-weight:800;display:flex;box-shadow:0 0 0 3px #ff6a1a2e}.lesson-body .ls-step-line{width:2px;min-height:var(--sp-4);background:var(--border-strong);flex:1;margin:4px 0}.lesson-body .ls-step-content{padding:4px 0 var(--sp-4);color:var(--text);flex:1;font-size:15px;line-height:1.65}.lesson-body .ls-step:last-child .ls-step-content{padding-bottom:0}@media (width<=600px){.lesson-body .ls-flashcard-group{grid-template-columns:1fr}.lesson-body .ls-tab-btn{padding:var(--sp-2) var(--sp-3);font-size:13px}}.ls-graduation{border-radius:var(--radius-lg);padding-top:var(--sp-4);padding-bottom:var(--sp-5);background:radial-gradient(120% 60% at 50% 0,#fbbf241a 0%,#fbbf2400 60%),linear-gradient(#ff6a1a0b 0%,#ff6a1a00 45%);position:relative}.ls-graduation .ls-grad-badge{align-items:center;gap:var(--sp-2);color:#3b2500;letter-spacing:.4px;text-transform:uppercase;margin-bottom:var(--sp-3);background:linear-gradient(135deg,#fbbf24,#f59e0b);border-radius:999px;padding:6px 16px 6px 12px;font-size:12.5px;font-weight:800;display:inline-flex;box-shadow:0 4px 14px #f59e0b4d}.ls-graduation>h1{padding-bottom:var(--sp-3);border-bottom:3px solid #fbbf248c;font-size:30px;line-height:1.25}.ls-graduation .lesson-body .ls-block{border-color:#f59e0b4d;box-shadow:0 3px 14px #f59e0b1a}.ls-graduation .lesson-body h2{border-left-color:#f59e0b}.ls-graduation .ls-gate-btn{background:linear-gradient(135deg,#f59e0b,#ea580c);border-color:#0000}@media (width<=640px){.ls-graduation>h1{font-size:24px}.ls-graduation{padding-top:var(--sp-3);padding-bottom:var(--sp-4)}}