:root{
      --red:#d71920;--red2:#b80f16;--ink:#172033;--text:#263044;--muted:#667085;--bg:#f5f7fb;--card:#fff;--line:#e5e8ef;--soft:#f2f4f8;--green:#0f9f6e;--amber:#b7791f;--blue:#1f66d1;--bad:#d92d20;--shadow:0 18px 50px rgba(20,30,55,.10);--r:22px
    }
    *{box-sizing:border-box} #course,#about{scroll-margin-top:84px} body{margin:0;font-family:Inter,Arial,system-ui,-apple-system,Segoe UI,sans-serif;background:var(--bg);color:var(--text)}.noscript{background:#fff1f2;border-bottom:1px solid #ffb6bd;color:#9f1118;font-weight:800;padding:12px 16px;text-align:center}
    .wrap{width:min(1180px,calc(100% - 32px));margin:auto}.top{position:sticky;top:0;z-index:20;background:rgba(255,255,255,.88);backdrop-filter:blur(16px);border-bottom:1px solid var(--line)}.topin{height:72px;display:flex;align-items:center;justify-content:space-between}.logo{display:flex;align-items:center;gap:12px;font-weight:900;color:var(--ink)}.mark{width:44px;height:34px;background:var(--red);border-radius:8px 8px 14px 8px;display:grid;place-items:center;color:white;font-weight:1000;letter-spacing:-.06em}.nav{display:flex;gap:18px;align-items:center}.nav a{color:var(--muted);text-decoration:none;font-size:14px;font-weight:700}.btn{border:0;background:var(--red);color:white;border-radius:999px;padding:13px 19px;font-weight:850;cursor:pointer;box-shadow:0 12px 24px rgba(215,25,32,.18);transition:.18s}.btn:hover{transform:translateY(-1px)}.btn.ghost{background:#fff;color:var(--ink);border:1px solid var(--line);box-shadow:none}.btn:disabled{opacity:.55;cursor:not-allowed;transform:none}
    .hero{padding:48px 0 24px;display:grid;grid-template-columns:1.05fr .95fr;gap:24px;align-items:center}.label{display:inline-flex;gap:8px;align-items:center;background:#fff;border:1px solid var(--line);border-radius:999px;padding:8px 12px;color:#49566f;font-size:13px;font-weight:750}.h1{font-size:clamp(36px,5.4vw,66px);line-height:.98;letter-spacing:-.055em;margin:18px 0;color:var(--ink)}.lead{font-size:19px;line-height:1.58;color:#526078;max-width:720px}.actions{display:flex;gap:12px;flex-wrap:wrap;margin-top:18px}.metrics{display:grid;grid-template-columns:repeat(3,1fr);gap:12px;margin-top:16px}.metric{background:white;border:1px solid var(--line);border-radius:18px;padding:17px;box-shadow:0 8px 24px rgba(20,30,55,.04)}.metric b{display:block;font-size:28px;color:var(--ink)}.metric span{font-size:13px;color:var(--muted)}
    .panelMock{background:#fff;border:1px solid var(--line);border-radius:30px;box-shadow:var(--shadow);overflow:hidden}.mockTop{height:54px;background:#fafbfe;border-bottom:1px solid var(--line);display:flex;align-items:center;justify-content:space-between;padding:0 18px}.dots{display:flex;gap:7px}.dot{width:10px;height:10px;border-radius:50%;background:#d0d5dd}.mockBody{display:grid;grid-template-columns:1fr;padding:18px;gap:12px}.chat{border:1px solid var(--line);border-radius:18px;padding:14px;background:#fbfcff}.from{font-size:12px;color:var(--muted);font-weight:800;margin-bottom:7px}.bubble{background:#f0f3f8;border-radius:16px 16px 16px 4px;padding:12px;line-height:1.45;color:#364154}.agent{background:#fff4f4;border-color:#ffd6d8}.agent .bubble{background:#fff;color:#344054;border:1px solid #ffd6d8}.ticket{display:grid;grid-template-columns:1fr 1fr;gap:10px}.ticket div{background:#f8fafc;border:1px solid var(--line);border-radius:14px;padding:11px}.ticket small{display:block;color:var(--muted);font-weight:800}.ticket b{color:var(--ink)}
    section{padding:24px 0}.grid3{display:grid;grid-template-columns:repeat(3,1fr);gap:16px}.card{background:#fff;border:1px solid var(--line);border-radius:var(--r);padding:18px;box-shadow:0 10px 30px rgba(20,30,55,.04)}.card h3{margin:0 0 10px;color:var(--ink)}.card p,.muted{color:var(--muted);line-height:1.58}.course{display:grid;grid-template-columns:340px 1fr;gap:12px;align-items:start}.side{position:sticky;top:92px;background:#fff;border:1px solid var(--line);border-radius:var(--r);padding:22px;box-shadow:0 10px 30px rgba(20,30,55,.04)}.timer{font-size:36px;font-weight:950;color:var(--ink);margin:8px 0}.progress{height:12px;background:#eef1f6;border-radius:999px;overflow:hidden}.progress span{height:100%;display:block;width:0;background:linear-gradient(90deg,var(--red),#ff7b7f);transition:.35s}.steps{display:grid;gap:8px;margin-top:16px}.steps div{border:1px solid var(--line);border-radius:14px;padding:11px;background:#fbfcff;color:#536078;font-size:14px;font-weight:750}.steps div.active{border-color:#ffd0d2;background:#fff3f3;color:var(--red)}.work{background:#fff;border:1px solid var(--line);border-radius:var(--r);padding:18px;box-shadow:var(--shadow);min-height:620px}.lessonHero{border:1px solid #ffd7d9;background:linear-gradient(180deg,#fff7f7,#fff);border-radius:24px;padding:22px;margin-top:10px}.lessonHero h3{margin:0 0 10px;color:var(--ink)}.checklist{display:grid;gap:10px;margin:16px 0}.check{display:flex;gap:10px;align-items:flex-start;background:#f8fafc;border:1px solid var(--line);border-radius:16px;padding:13px}.check i{font-style:normal;color:var(--green);font-weight:1000}.scenarioHead{display:flex;justify-content:space-between;gap:16px;align-items:flex-start;margin-bottom:10px}.badge{display:inline-flex;border-radius:999px;border:1px solid var(--line);background:#f8fafc;padding:7px 10px;color:#536078;font-size:12px;font-weight:850}.ticketBox{display:grid;grid-template-columns:1fr 320px;gap:16px;margin-top:12px}.dialog{border:1px solid var(--line);border-radius:22px;background:#fbfcff;padding:16px}.message{margin-bottom:12px}.message .name{font-size:12px;font-weight:900;color:#667085;margin-bottom:5px}.message .txt{background:#fff;border:1px solid var(--line);border-radius:16px;padding:13px;line-height:1.48}.message.client .txt{border-radius:16px 16px 16px 4px}.message.operator .txt{background:#fff5f5;border-color:#ffd7d9;border-radius:16px 16px 4px 16px}.data{border:1px solid var(--line);border-radius:22px;padding:16px;background:#fff}.row{padding:11px 0;border-bottom:1px solid var(--line)}.row:last-child{border-bottom:0}.row small{display:block;color:var(--muted);font-weight:850;text-transform:uppercase;font-size:11px;letter-spacing:.04em;margin-bottom:4px}.row b{color:var(--ink)}.task{margin-top:10px;background:#f7f8fb;border:1px solid var(--line);border-radius:18px;padding:12px;line-height:1.5}.choices{display:grid;grid-template-columns:1fr 1fr;gap:10px;margin-top:16px}.choice{background:#fff;border:1px solid var(--line);border-radius:16px;padding:14px;text-align:left;cursor:pointer;font-weight:750;line-height:1.42;color:#344054}.choice:hover{border-color:#f3a4a8;transform:translateY(-1px)}.choice.correct{border-color:#7ad7b4;background:#eefbf6}.choice.wrong{border-color:#ff9aa2;background:#fff1f2}.feedback{display:none;margin-top:10px;border-radius:18px;padding:16px;line-height:1.58}.feedback.show{display:block}.feedback.good{background:#eefbf6;border:1px solid #a9e8d0}.feedback.no{background:#fff1f2;border:1px solid #ffb6bd}.writeBox{margin-top:10px;display:none}.writeBox.show{display:block}.writeBox textarea{width:100%;min-height:112px;border:1px solid var(--line);border-radius:16px;padding:14px;resize:vertical;color:#344054;background:#fff}.sample{margin-top:10px;background:#f8fafc;border:1px solid var(--line);border-radius:16px;padding:13px;color:#48546a;display:none}.sample.show{display:block}.result{display:none;text-align:center}.score{font-size:72px;font-weight:1000;color:var(--red);letter-spacing:-.05em}.breakdown{text-align:left;margin-top:18px}.barLine{display:grid;grid-template-columns:170px 1fr 52px;gap:10px;align-items:center;margin:10px 0}.miniBar{height:10px;background:#eef1f6;border-radius:999px;overflow:hidden}.miniBar span{display:block;height:100%;background:var(--red);border-radius:999px}.hidden{display:none!important}.footer{text-align:center;color:var(--muted);padding:34px 0 54px}@media(max-width:960px){.hero,.course,.ticketBox{grid-template-columns:1fr}.grid3,.metrics,.choices{grid-template-columns:1fr}.side{position:relative;top:auto}.nav a{display:none}.ticket{grid-template-columns:1fr}}


    /* Mobile-first refinement layer */
    @media (max-width:760px){
      :root{--r:18px;--shadow:0 10px 28px rgba(20,30,55,.08)}
      html,body{max-width:100%;overflow-x:hidden;-webkit-text-size-adjust:100%}
      body{padding-bottom:env(safe-area-inset-bottom)}
      .wrap{width:min(100% - 20px,1180px)}
      .top{z-index:60}
      .topin{height:58px;gap:10px}
      .logo{gap:8px;font-size:14px;min-width:0}.logo span{white-space:nowrap;overflow:hidden;text-overflow:ellipsis}.mark{width:38px;height:30px;border-radius:7px 7px 12px 7px;font-size:13px;flex:0 0 auto}
      .nav{gap:8px}.nav .btn{padding:10px 13px;font-size:13px;box-shadow:none}.nav a{display:none!important}
      .hero{padding:30px 0 22px;gap:20px}.label{font-size:12px;line-height:1.35;border-radius:14px;align-items:flex-start}.h1{font-size:clamp(30px,10vw,42px);line-height:1.02;letter-spacing:-.04em;margin:14px 0}.lead{font-size:16px;line-height:1.5}.actions{display:grid;grid-template-columns:1fr;gap:10px;margin-top:18px}.actions .btn,.actions a.btn{width:100%;text-align:center;padding:15px 16px}
      .metrics{grid-template-columns:repeat(3,1fr);gap:8px;margin-top:16px}.metric{padding:12px 10px;border-radius:15px}.metric b{font-size:20px}.metric span{font-size:11px;line-height:1.25}
      .panelMock{border-radius:22px}.mockTop{height:46px;padding:0 14px}.mockBody{padding:12px}.ticket{grid-template-columns:1fr}.chat{padding:12px}.bubble{font-size:14px;padding:11px}
      section{padding:22px 0}.grid3{gap:10px}.card{padding:18px;border-radius:18px}.card h3{font-size:18px}.card p{font-size:14px}
      .course{gap:12px}.side{position:sticky;top:58px;z-index:45;border-radius:0 0 18px 18px;margin-left:-10px;margin-right:-10px;border-left:0;border-right:0;padding:10px 12px;box-shadow:0 10px 22px rgba(20,30,55,.08)}
      .side h2,.side p.muted{display:none}.timer{font-size:20px;margin:0;line-height:1}.progress{height:8px;margin-top:8px}.steps{display:flex;gap:6px;overflow-x:auto;margin-top:8px;padding-bottom:2px;scrollbar-width:none}.steps::-webkit-scrollbar{display:none}.steps div{white-space:nowrap;font-size:12px;padding:8px 10px;border-radius:999px;flex:0 0 auto}
      .work{min-height:auto;padding:16px;border-radius:18px}.work h2{font-size:22px;line-height:1.16;margin:0 0 10px}.lessonHero{padding:16px;border-radius:18px}.checklist{gap:8px}.check{padding:11px;border-radius:14px;font-size:14px}.scenarioHead{display:grid;grid-template-columns:1fr;gap:8px;margin-bottom:12px}.scenarioHead h2{font-size:22px;line-height:1.16}.badge{width:max-content;max-width:100%;font-size:11px;line-height:1.2}
      .ticketBox{gap:10px}.dialog,.data{border-radius:18px;padding:12px}.message{margin-bottom:10px}.message .txt{font-size:14px;line-height:1.45;padding:11px;border-radius:14px}.row{padding:10px 0}.row b{font-size:14px;line-height:1.35}.task{padding:13px;border-radius:15px;font-size:14px}.choices{grid-template-columns:1fr;gap:8px}.choice{min-height:54px;padding:14px 13px;border-radius:15px;font-size:15px;line-height:1.35;touch-action:manipulation}.choice:hover{transform:none}
      .feedback{padding:13px;border-radius:15px;font-size:14px}.writeBox textarea{min-height:120px;border-radius:15px;font-size:16px;line-height:1.45}.writeBox .btn,#nextBtn{width:100%;margin-top:8px;padding:15px 16px}.sample{font-size:14px;border-radius:15px}.result .score,.score{font-size:54px}.barLine{grid-template-columns:1fr;gap:6px;background:#fbfcff;border:1px solid var(--line);border-radius:14px;padding:10px}.barLine span{text-align:right}.footer{padding:24px 12px 34px;font-size:13px}
    }
    @media (max-width:420px){
      .wrap{width:min(100% - 16px,1180px)}.topin{height:54px}.nav .btn{padding:9px 11px;font-size:12px}.logo span{max-width:145px}.hero{padding-top:24px}.h1{font-size:30px}.lead{font-size:15px}.metrics{grid-template-columns:1fr}.metric{display:flex;justify-content:space-between;align-items:center;gap:12px}.metric b{font-size:22px}.metric span{text-align:right}.panelMock{display:none}.side{top:54px;margin-left:-8px;margin-right:-8px}.work{padding:14px}.data{order:-1}.ticketBox{display:flex;flex-direction:column}.choice{font-size:14px}.caseTop,.scenarioHead{gap:6px}
    }

    /* Polished desktop layer */
    html{scroll-behavior:smooth}
    body{background:
      linear-gradient(180deg,#f7f9fd 0%,#eef2f8 44%,#f7f8fb 100%);
      text-rendering:optimizeLegibility}
    body:before{content:"";position:fixed;inset:0;pointer-events:none;background:
      linear-gradient(90deg,rgba(215,25,32,.035),transparent 38%,rgba(31,102,209,.045));
      z-index:-1}
    .top{box-shadow:0 6px 24px rgba(20,30,55,.05)}
    .topin{gap:18px}.logo span{letter-spacing:-.01em}
    .mark{box-shadow:inset 0 -10px 18px rgba(105,0,8,.16),0 9px 22px rgba(215,25,32,.18)}
    .nav a{position:relative;padding:8px 0}.nav a:after{content:"";position:absolute;left:0;right:0;bottom:2px;height:2px;background:var(--red);border-radius:9px;opacity:0;transform:scaleX(.6);transition:.18s}
    .nav a:hover{color:var(--ink)}.nav a:hover:after{opacity:1;transform:scaleX(1)}
    .btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;min-height:44px;line-height:1;text-decoration:none}
    .btn:focus-visible,.choice:focus-visible,textarea:focus-visible{outline:3px solid rgba(31,102,209,.22);outline-offset:3px}
    .hero{min-height:auto;padding:42px 0 28px}
    .label{box-shadow:0 8px 26px rgba(20,30,55,.05)}
    .h1{max-width:780px}.lead{color:#465572}
    .metrics{max-width:720px}.metric{transition:transform .18s,box-shadow .18s,border-color .18s}
    .metric:hover{transform:translateY(-2px);border-color:#d7dce7;box-shadow:0 14px 34px rgba(20,30,55,.07)}
    .panelMock{position:relative;isolation:isolate}
    .panelMock:before{content:"";position:absolute;inset:0;background:linear-gradient(135deg,rgba(215,25,32,.055),transparent 42%,rgba(31,102,209,.05));z-index:-1}
    .mockTop b:before{content:"";display:inline-block;width:8px;height:8px;border-radius:50%;background:var(--green);margin-right:8px;box-shadow:0 0 0 4px rgba(15,159,110,.12)}
    section{padding:34px 0}#about{padding-top:10px}.grid3{align-items:stretch}
    .card{display:flex;flex-direction:column;min-height:100%;transition:transform .18s,border-color .18s,box-shadow .18s}
    .card:hover{transform:translateY(-2px);border-color:#d7dce7;box-shadow:0 16px 36px rgba(20,30,55,.07)}
    .card h3{font-size:20px;letter-spacing:-.015em}.card h3:before{content:"";display:block;width:36px;height:4px;border-radius:99px;background:var(--red);margin-bottom:13px}
    .course{gap:18px}.sideMeta{display:flex;justify-content:space-between;gap:10px;margin:10px 0 0;color:var(--muted);font-size:12px;font-weight:850}
    .sideMeta span{background:#f7f8fb;border:1px solid var(--line);border-radius:999px;padding:6px 9px}
    .steps div{transition:.18s}.steps div.active{box-shadow:inset 3px 0 0 var(--red)}
    .work{padding:24px;min-width:0;overflow:hidden}.work h2{color:var(--ink);letter-spacing:-.025em}
    #intro>.btn,#lesson>.btn{margin-top:18px}
    .lessonHero{position:relative;overflow:hidden}.lessonHero:before{content:"";position:absolute;left:0;top:0;bottom:0;width:5px;background:var(--red)}
    .check i{display:grid;place-items:center;flex:0 0 28px;width:28px;height:28px;border-radius:50%;background:#eaf8f2}.check span{min-width:0;overflow-wrap:anywhere}
    .scenarioHead h2{margin-top:0;color:var(--ink)}
    .badge{white-space:nowrap}.dialog,.data,.task{box-shadow:0 8px 22px rgba(20,30,55,.035)}
    .message .txt,.row b,.choice{overflow-wrap:anywhere}.choices{align-items:stretch}
    .choice{min-height:72px;transition:transform .18s,border-color .18s,background .18s,box-shadow .18s}
    .choice:hover:not(:disabled){box-shadow:0 10px 24px rgba(20,30,55,.06)}
    .choice:disabled{cursor:default}.choice.correct{box-shadow:0 0 0 3px rgba(15,159,110,.10)}.choice.wrong{box-shadow:0 0 0 3px rgba(217,45,32,.10)}
    .feedback,.sample{box-shadow:0 8px 22px rgba(20,30,55,.035)}
    .writeBox textarea{font:inherit;line-height:1.5;transition:border-color .18s,box-shadow .18s}
    .writeBox textarea:focus{border-color:#9bb8ee;box-shadow:0 0 0 4px rgba(31,102,209,.10);outline:0}
    .barLine{padding:8px 0}.footer{border-top:1px solid var(--line);margin-top:20px}
    @media(max-width:960px){.hero{min-height:auto}.panelMock{max-width:720px}.course{gap:14px}.work{padding:18px}.badge{white-space:normal}}
    @media(max-width:760px){
      .hero{min-height:auto}.sideMeta{margin-top:8px}.sideMeta span{padding:5px 8px}.steps div.active{box-shadow:none}
      #intro,#lesson,#case{min-width:0}
      #intro>.btn,#lesson>.btn{width:min(100%,230px);max-width:100%;margin-top:16px}
      .lessonHero{margin-bottom:0}
      .card:hover,.metric:hover{transform:none}.choice{min-height:58px}.footer{margin-top:8px}
    }
    @media(max-width:760px){
      .wrap,.course,.side,.work,.dialog,.data,.ticketBox,.lessonHero,.checklist,.scenarioHead{min-width:0;max-width:100%}
      .course{width:100%;overflow:hidden}
      .side{position:relative;top:auto;z-index:auto;width:100%;margin-left:0;margin-right:0;border-left:1px solid var(--line);border-right:1px solid var(--line);border-radius:16px;padding:10px;overflow:hidden}
      .sideMeta{display:grid;grid-template-columns:auto auto;align-items:center}
      .steps{width:100%;max-width:100%;min-width:0;overflow-x:auto;overflow-y:hidden;overscroll-behavior-x:contain}
      .steps div{flex:0 0 calc((100% - 6px)/2);max-width:none;min-width:0;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
      .steps div.active{max-width:none}
      .work{width:100%;overflow:hidden;margin-top:12px}
      .scenarioHead,.ticketBox{width:100%}
      .badge{max-width:100%;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
    }
    @media(max-width:420px){
      .side{margin-left:0;margin-right:0}
      .steps div{flex-basis:calc((100% - 6px)/2)}
      .steps div.active{max-width:none}
    }