:root{
    --bg:#F2F9F5;
    --card:#FFFFFF;
    --card-2:#E8F1EC;
    --label:#14241C;
    --sec:#5B7168;
    --tri:#97ACA2;
    --sep:rgba(20,36,28,.11);
    --brand:#0E8F5F;
    --brand-2:#E2F4EB;
    --ok:#0E8F5F;
    --ok-2:#E2F4EB;
    --no:#6B7F78;
    --no-2:#E7EEEA;
    --ring:rgba(14,143,95,.16);
    --on-fill:#FFFFFF;
    --shadow:0 1px 2px rgba(20,36,28,.05), 0 12px 30px -20px rgba(20,36,28,.45);
    --shadow-lg:0 2px 6px rgba(20,36,28,.07), 0 40px 80px -40px rgba(20,36,28,.5);
    --spring:cubic-bezier(.22,1,.36,1);
    --sans:"Noto Sans KR",-apple-system,BlinkMacSystemFont,"Apple SD Gothic Neo",system-ui,sans-serif;
    --serif:"Noto Serif KR","Noto Sans KR",serif;
    --display:"Black Han Sans","Noto Sans KR",sans-serif;
  }
  @media (prefers-color-scheme: dark){
    :root:not([data-theme="light"]){
      --bg:#08120D;
      --card:#131E18;
      --card-2:#1C2B23;
      --label:#E9F4EE;
      --sec:#9AB2A6;
      --tri:#6C8278;
      --sep:rgba(255,255,255,.10);
      --brand:#45C894;
      --brand-2:#0C2A1E;
      --ok:#45C894;
      --ok-2:#0C2A1E;
      --no:#97AFA4;
      --no-2:#1C2B23;
      --ring:rgba(69,200,148,.18);
      --on-fill:#04140C;
      --shadow:0 1px 2px rgba(0,0,0,.5), 0 12px 30px -18px rgba(0,0,0,.9);
      --shadow-lg:0 2px 8px rgba(0,0,0,.6), 0 40px 80px -40px rgba(0,0,0,1);
    }
  }
  :root[data-theme="dark"]{
    --bg:#08120D; --card:#131E18; --card-2:#1C2B23; --label:#E9F4EE; --sec:#9AB2A6;
    --tri:#6C8278; --sep:rgba(255,255,255,.10); --brand:#45C894; --brand-2:#0C2A1E;
    --ok:#45C894; --ok-2:#0C2A1E; --no:#97AFA4; --no-2:#1C2B23;
    --ring:rgba(69,200,148,.18); --on-fill:#04140C;
    --shadow:0 1px 2px rgba(0,0,0,.5), 0 12px 30px -18px rgba(0,0,0,.9);
    --shadow-lg:0 2px 8px rgba(0,0,0,.6), 0 40px 80px -40px rgba(0,0,0,1);
  }

  *,*::before,*::after{box-sizing:border-box}

  body{
    margin:0;
    background:var(--bg);
    color:var(--label);
    font-family:var(--sans);
    font-size:16px;line-height:1.6;
    -webkit-font-smoothing:antialiased;
    -webkit-tap-highlight-color:transparent;
  }

  /* ---------- phone shell ---------- */
  .stage{display:flex;justify-content:center;padding-block:0}
  .app{
    position:relative;
    width:100%;max-width:440px;
    min-height:100svh;
    background:var(--bg);
    overflow:hidden;
    padding-inline:20px;
    padding-block:0 clamp(14px,2.6svh,40px);
    display:flex;flex-direction:column;
  }
  #intro{display:flex;flex-direction:column;flex:1 1 auto;min-height:0}
  @media (min-width:600px){
    .stage{padding-block:40px;align-items:flex-start}
    .app{
      width:400px;height:820px;min-height:0;
      border-radius:46px;
      box-shadow:var(--shadow-lg), 0 0 0 10px var(--card), 0 0 0 11px var(--sep);
      overflow-y:auto;overflow-x:hidden;
      scrollbar-width:none;
      padding-block:0 34px;
    }
    .app::-webkit-scrollbar{display:none}
    .grabber{
      position:sticky;bottom:-34px;
      width:120px;height:5px;border-radius:99px;
      background:var(--tri);opacity:.5;margin:18px auto -18px;
    }
  }
  @media (max-width:599px){ .grabber{display:none} }

  /* ---------- primitives ---------- */
  .card{
    background:var(--card);
    border-radius:24px;
    box-shadow:var(--shadow);
  }
  h1,h2,h3{margin:0;text-wrap:balance;letter-spacing:-.02em}
  .kicker{
    font-size:11.5px;font-weight:700;letter-spacing:.14em;
    text-transform:uppercase;color:var(--brand);
  }

  button{font-family:inherit;color:inherit;cursor:pointer}
  .btn{
    display:flex;align-items:center;justify-content:center;gap:8px;
    width:100%;border:0;
    font-size:clamp(16px,4.3vw,17px);font-weight:700;letter-spacing:-.01em;
    padding:clamp(14px,2.1svh,17px) 20px;border-radius:18px;
    background:var(--brand);color:var(--on-fill);
    transition:transform .22s var(--spring), filter .2s ease;
  }
  .btn:active{transform:scale(.96)}
  .btn.tonal{background:var(--brand-2);color:var(--brand)}
  .btn.plain{background:transparent;color:var(--brand);font-weight:600;font-size:16px;padding:13px}
  .btn.solid{background:var(--brand);color:#fff}
  .btn.ghostw{background:rgba(255,255,255,.18);color:#fff}
  .btn.plainw{background:transparent;color:rgba(255,255,255,.82);font-weight:600;font-size:16px;padding:13px}
  :focus-visible{outline:2.5px solid var(--brand);outline-offset:3px;border-radius:14px}

  /* ---------- nav ---------- */
  .nav{
    position:sticky;top:0;z-index:5;
    display:flex;align-items:center;gap:12px;
    height:56px;margin-inline:-20px;padding-inline:14px;
    background:color-mix(in srgb, var(--bg) 82%, transparent);
    backdrop-filter:saturate(180%) blur(18px);
    -webkit-backdrop-filter:saturate(180%) blur(18px);
  }
  .icon-btn{
    flex:none;width:34px;height:34px;border:0;border-radius:50%;
    background:var(--card);box-shadow:var(--shadow);
    display:grid;place-items:center;
    transition:transform .2s var(--spring);
  }
  .icon-btn:active{transform:scale(.9)}
  .icon-btn svg{width:16px;height:16px;stroke:var(--label);fill:none;stroke-width:2.2;stroke-linecap:round;stroke-linejoin:round}
  .nav .title{flex:1;font-size:15px;font-weight:700;letter-spacing:-.01em}
  .nav .count{
    font-size:13px;font-weight:700;color:var(--sec);
    font-variant-numeric:tabular-nums;letter-spacing:.02em;
  }
  .rail{height:4px;border-radius:99px;background:var(--sep);margin:2px 0 20px;overflow:hidden}
  .rail b{
    display:block;height:100%;border-radius:99px;background:var(--brand);
    width:0;transition:width .5s var(--spring);
  }

  /* ---------- intro ---------- */
  .hero{padding:clamp(10px,1.8svh,20px) 0 4px}
  .cover{
    background:var(--brand);
    border-radius:26px;
    padding:clamp(17px,2.4svh,24px) clamp(18px,5vw,22px) 0;
    color:#fff;
    box-shadow:var(--shadow);
    overflow:hidden;
  }
  .cover .pill{
    display:inline-block;
    background:rgba(255,255,255,.18);
    border-radius:99px;padding:5px 12px;
    font-size:clamp(11px,3.2vw,12.5px);font-weight:700;letter-spacing:-.01em;
    margin-bottom:clamp(9px,1.5svh,15px);
  }
  .cover h1{
    font-family:var(--display);font-weight:400;
    font-size:clamp(24px,min(7.6vw,4.3svh),35px);line-height:1.3;letter-spacing:-.005em;color:#fff;
  }
  .cover h1 em{font-style:normal;color:#FFFFFF;box-shadow:inset 0 -.14em 0 rgba(255,255,255,.55)}
  .cover .deco{display:block;width:min(198px,42vw);max-width:72%;height:auto;margin:clamp(2px,.8svh,10px) 0 0 auto}
  .lede{margin:clamp(10px,1.6svh,16px) 4px 0;font-size:clamp(13px,3.5vw,15px);color:var(--sec);line-height:1.62}
  @media (max-height:700px){ .cover .deco{width:min(150px,34vw)} }
  @media (max-height:620px){ .cover .deco{display:none} .cover{padding-bottom:clamp(14px,2svh,18px)} }

  .seg{
    display:grid;grid-template-columns:1fr 1fr;gap:4px;
    background:var(--card-2);border-radius:18px;padding:4px;
    position:relative;box-shadow:inset 0 0 0 1px var(--sep);
    margin-top:clamp(11px,1.7svh,18px);
  }
  .seg .thumb{
    position:absolute;inset:4px 50% 4px 4px;
    background:var(--card);border-radius:14px;
    box-shadow:var(--shadow);
    transition:transform .42s var(--spring);
  }
  .seg[data-sel="child"] .thumb{transform:translateX(calc(100% + 4px))}
  .seg button{
    position:relative;z-index:1;border:0;background:transparent;
    padding:clamp(9px,1.4svh,11px) 6px;border-radius:14px;
    font-size:clamp(14px,3.8vw,15px);font-weight:700;color:var(--sec);
    transition:color .3s ease;
  }
  .seg button[aria-selected="true"]{color:var(--label)}

  .blurb{
    margin-top:clamp(9px,1.4svh,14px);padding:clamp(13px,1.9svh,18px) 18px;
    display:flex;gap:14px;align-items:flex-start;
  }
  .blurb .ko{
    flex:none;width:clamp(38px,5.4svh,44px);height:clamp(38px,5.4svh,44px);border-radius:15px;
    background:var(--brand-2);color:var(--brand);
    display:grid;place-items:center;
    font-family:var(--display);font-size:clamp(19px,2.8svh,22px);font-weight:400;
  }
  .blurb b{display:block;font-size:clamp(14.5px,3.9vw,15.5px);letter-spacing:-.01em}
  .blurb small{display:block;color:var(--sec);font-size:clamp(12.5px,3.4vw,13.5px);line-height:1.55;margin-top:3px}


  .cta{margin-top:auto;padding-top:clamp(12px,2svh,18px)}
  /* ---------- question ---------- */
  .qwrap{position:relative}
  .qcard{padding:24px 22px 22px}
  .chip{
    display:inline-flex;align-items:center;gap:7px;
    font-size:11.5px;font-weight:700;letter-spacing:.04em;
    color:var(--brand);background:var(--brand-2);
    padding:5px 12px;border-radius:99px;margin-bottom:16px;
  }
  .stembox{
    background:var(--card-2);
    border:1px solid var(--sep);
    border-radius:12px;
    padding:17px 17px 18px;
  }
  .stem{
    font-family:var(--serif);
    font-size:18.5px;line-height:1.72;font-weight:700;
    letter-spacing:-.01em;margin:0;
  }
  .stem u{
    text-decoration:none;
    color:var(--brand);
    box-shadow:inset 0 -.1em 0 var(--brand);
  }
  .choices{list-style:none;margin:20px 0 0;padding:0;display:flex;flex-direction:column;gap:9px}
  .choice{
    display:flex;align-items:center;gap:12px;width:100%;text-align:left;
    border:0;background:var(--card-2);border-radius:17px;
    padding:14px 16px;font-size:15.5px;line-height:1.45;font-weight:500;
    box-shadow:inset 0 0 0 1px var(--sep);
    transition:transform .24s var(--spring), background .2s ease, box-shadow .2s ease, color .2s ease;
  }
  .choice em{
    flex:none;font-style:normal;width:24px;height:24px;border-radius:50%;
    background:var(--card);box-shadow:inset 0 0 0 1px var(--sep);
    display:grid;place-items:center;
    font-size:12px;font-weight:700;color:var(--tri);
    transition:background .2s ease,color .2s ease,box-shadow .2s ease;
  }
  .choice:active{transform:scale(.975)}
  .choice:disabled{cursor:default}
  .choice.correct{background:var(--ok);color:var(--on-fill);box-shadow:0 8px 20px -10px var(--ok)}
  .choice.wrong{background:var(--no);color:var(--on-fill);box-shadow:0 8px 20px -10px var(--no)}
  .choice.correct em,.choice.wrong em{background:rgba(255,255,255,.28);color:inherit;box-shadow:none}
  .choice.answer{
    background:var(--ok-2);color:var(--ok);
    box-shadow:inset 0 0 0 2px var(--ok);
  }
  .choice.answer em{background:transparent;color:var(--ok);box-shadow:inset 0 0 0 1.5px var(--ok)}
  .choice.muted{opacity:.45}

  @media (max-height:680px){
    .rail{margin:2px 0 14px}
    .qcard{padding:20px 18px 18px}
    .stembox{padding:14px 15px 15px}
    .stem{font-size:17.5px;line-height:1.62}
    .choices{gap:8px;margin-top:16px}
    .choice{padding:12px 14px;font-size:15px}
  }

  /* answer feedback */
  .fb{
    margin-top:18px;padding:16px 17px;border-radius:19px;
    background:var(--card-2);box-shadow:inset 0 0 0 1px var(--sep);
    animation:drop .38s var(--spring) both;
  }
  .fb .verdict{display:flex;align-items:center;gap:9px;font-size:15px;font-weight:700;letter-spacing:-.01em}
  .fb .verdict .mark{flex:none;width:24px;height:24px;border-radius:50%;display:grid;place-items:center;font-size:13px;font-weight:700}
  .fb .verdict.ok{color:var(--ok)}
  .fb .verdict.no{color:var(--no)}
  .fb p{margin:10px 0 0;font-size:13.5px;line-height:1.72;color:var(--sec)}
  .fb p b{color:var(--label);font-weight:700}
  .fb .btn{margin-top:16px;padding:14px 18px;font-size:16px;border-radius:17px}


  /* ---------- result ---------- */
  .score{padding:26px 22px 24px;text-align:center}
  .dial{position:relative;width:168px;height:168px;margin:0 auto 6px}
  .dial svg{width:100%;height:100%;transform:rotate(-90deg)}
  .dial .bgc{fill:none;stroke:var(--ring);stroke-width:13}
  .dial .fgc{
    fill:none;stroke:var(--brand);stroke-width:13;stroke-linecap:round;
    transition:stroke-dashoffset 1.15s var(--spring);
  }
  .dial .mid{
    position:absolute;inset:0;display:grid;place-content:center;gap:0;
  }
  .dial .num{
    font-family:var(--display);font-size:56px;font-weight:400;line-height:1;
    font-variant-numeric:tabular-nums;letter-spacing:-.02em;color:var(--brand);
  }
  .dial .den{font-size:13px;font-weight:600;color:var(--tri);margin-top:6px}
  .score .lv{font-size:12px;font-weight:700;letter-spacing:.14em;color:var(--brand);margin-top:10px}
  .score h2{font-family:var(--display);font-weight:400;font-size:25px;line-height:1.38;margin-top:8px}

  .sect{margin-top:14px;padding:20px 22px}
  .sect h3{font-size:15.5px;margin-bottom:16px;display:flex;align-items:center;gap:9px}
  .sect h3 .no{
    flex:none;width:22px;height:22px;border-radius:50%;
    background:var(--brand);color:#fff;
    display:grid;place-items:center;
    font-size:12px;font-weight:700;letter-spacing:0;
  }
  .sect > p.body{margin:0;font-size:14.5px;line-height:1.78;color:var(--sec);font-family:var(--serif);font-weight:500}
  .sect h3 .expand{
    margin-left:auto;border:0;border-radius:99px;
    background:var(--brand-2);color:var(--brand);
    padding:6px 12px;font-size:11.5px;font-weight:700;letter-spacing:0;
    transition:transform .2s var(--spring);
  }
  .sect h3 .expand:active{transform:scale(.94)}

  /* grade steps */
  .steps{display:grid;grid-template-columns:repeat(4,1fr);gap:7px}
  .step{
    padding:12px 4px 10px;border-radius:14px;text-align:center;
    background:var(--card-2);box-shadow:inset 0 0 0 1px var(--sep);
  }
  .step b{display:block;font-size:12.5px;font-weight:700;color:var(--sec)}
  .step .dots{display:flex;justify-content:center;gap:4px;margin:9px 0 7px}
  .step .dots i{width:7px;height:7px;border-radius:50%;background:var(--sep);display:block}
  .step .dots i.on{background:var(--brand)}
  .step small{font-size:11px;color:var(--tri);font-variant-numeric:tabular-nums}
  .step.pass{background:var(--brand-2);box-shadow:none}
  .step.pass b{color:var(--brand)}
  .step.hit{background:var(--brand);box-shadow:none}
  .step.hit b,.step.hit small{color:#fff}
  .step.hit .dots i{background:rgba(255,255,255,.38)}
  .step.hit .dots i.on{background:#fff}
  .gradenote{margin:15px 0 0;font-size:13px;line-height:1.7;color:var(--sec)}
  .gradenote b{color:var(--brand)}

  .bars{display:flex;flex-direction:column;gap:13px}
  .bar{display:grid;grid-template-columns:70px 1fr 32px;align-items:center;gap:11px}
  .bar span{font-size:13px;color:var(--sec)}
  .bar .t{height:9px;border-radius:99px;background:var(--card-2);box-shadow:inset 0 0 0 1px var(--sep);overflow:hidden}
  .bar .f{display:block;height:100%;border-radius:99px;background:var(--brand);width:0;transition:width .9s var(--spring)}
  .bar .f.low{background:var(--no)}
  .bar b{font-size:12.5px;font-weight:700;text-align:right;color:var(--sec);font-variant-numeric:tabular-nums}
  .weak{margin:16px 0 0;font-size:13px;color:var(--sec)}
  .weak b{color:var(--no)}

  .revsum{margin:0;font-size:13.5px;line-height:1.7;color:var(--sec)}
  .revsum b{color:var(--brand)}
  .review{margin-top:4px}
  .revi{border-top:1px solid var(--sep);padding:15px 0 2px}
  .revi:first-child{border-top:0;padding-top:4px}
  .revi .rq{
    display:flex;align-items:flex-start;gap:10px;
    margin:0 0 8px;font-size:14.5px;line-height:1.55;font-weight:500;
  }
  .revi .mark{
    flex:none;width:22px;height:22px;border-radius:50%;margin-top:1px;
    display:grid;place-items:center;font-size:12px;font-weight:700;
  }
  .mark.o{background:var(--ok-2);color:var(--ok)}
  .mark.x{background:var(--no-2);color:var(--no)}
  .revi .body{
    margin:0 0 4px 32px;font-size:13.5px;line-height:1.72;color:var(--sec);
  }
  .revi .body b{color:var(--label)}
  @keyframes drop{from{opacity:0;transform:translateY(-6px)}to{opacity:1;transform:none}}
  .review.opening{animation:drop .34s var(--spring) both}

  .promo{
    margin-top:14px;padding:26px 22px;border-radius:26px;
    background:var(--brand);color:#fff;
    box-shadow:var(--shadow);
  }
  .promo .kicker{color:rgba(255,255,255,.72)}
  .promo h3{font-family:var(--display);font-weight:400;font-size:26px;line-height:1.36;margin:10px 0 12px;color:#fff}
  .promo p{margin:0 0 18px;font-size:14.5px;line-height:1.74;color:rgba(255,255,255,.86);font-family:var(--serif);font-weight:500}
  .stack{display:flex;flex-direction:column;gap:9px}
  .toast{height:20px;margin-top:8px;text-align:center;font-size:12.5px;color:#fff}
  .ig{
    width:18px;height:18px;flex:none;fill:none;stroke:currentColor;
    stroke-width:2;stroke-linecap:round;stroke-linejoin:round;
  }

  /* share sheet */
  .mask{
    position:fixed;inset:0;z-index:60;
    display:flex;align-items:center;justify-content:center;padding:20px;
    background:rgba(6,12,9,.62);
    backdrop-filter:blur(10px);-webkit-backdrop-filter:blur(10px);
    animation:fadeIn .26s ease both;
  }
  @keyframes fadeIn{from{opacity:0}to{opacity:1}}
  .sheetbox{
    width:100%;max-width:360px;
    background:var(--card);border-radius:26px;padding:20px;
    box-shadow:var(--shadow-lg);
    animation:pop .42s var(--spring) both;
    max-height:92vh;overflow-y:auto;
  }
  @keyframes pop{from{opacity:0;transform:translateY(24px) scale(.96)}to{opacity:1;transform:none}}
  .sheetbox img{
    display:block;width:100%;max-width:100%;border-radius:18px;
    box-shadow:var(--shadow);margin-bottom:16px;
  }
  .sheetbox h3{font-size:16px;margin-bottom:6px}
  .sheetbox p{margin:0 0 16px;font-size:13.5px;line-height:1.7;color:var(--sec)}
  .sheetbox .stack{gap:8px}

  /* ---------- motion ---------- */
  .in-up{animation:inUp .5s var(--spring) both}
  @keyframes inUp{from{opacity:0;transform:translateY(16px)}to{opacity:1;transform:none}}
  .in-next{animation:inNext .42s var(--spring) both}
  @keyframes inNext{from{opacity:0;transform:translateX(26px) scale(.98)}to{opacity:1;transform:none}}
  .in-prev{animation:inPrev .42s var(--spring) both}
  @keyframes inPrev{from{opacity:0;transform:translateX(-26px) scale(.98)}to{opacity:1;transform:none}}
  .out{animation:outL .2s ease both}
  @keyframes outL{to{opacity:0;transform:translateX(-18px) scale(.985)}}
  .d1{animation-delay:.05s}.d2{animation-delay:.11s}.d3{animation-delay:.17s}
  .d4{animation-delay:.23s}.d5{animation-delay:.29s}

  [hidden]{display:none !important}
  @media (prefers-reduced-motion:reduce){
    *,*::before,*::after{animation-duration:.01ms !important;transition-duration:.01ms !important}
  }