:root{
    --red:#e8231f; --red-dark:#c81b18; --bg:#fafafa; --card:#ffffff;
    --text:#141414; --muted:#6b6b6b; --line:#eee; --radius:18px;
  }
  *{box-sizing:border-box}
  html,body{margin:0;padding:0;background:var(--bg);color:var(--text);
    font-family:'Inter',system-ui,sans-serif;}
  .wordmark{font-family:'Poppins',sans-serif;font-weight:800;letter-spacing:.5px}
  img{max-width:100%}
  .visually-hidden{position:absolute;width:1px;height:1px;padding:0;margin:-1px;
    overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}

  /* ---------- Loading screen ---------- */
  #loading{position:fixed;inset:0;background:var(--bg);display:flex;flex-direction:column;
    align-items:center;justify-content:center;gap:22px;z-index:50;transition:opacity .4s ease}
  #loading.hide{opacity:0;pointer-events:none}
  #loading img{width:120px;height:120px}
  #loading .wordmark{font-size:2.2rem;margin:0}
  .progress{width:280px;height:6px;background:var(--line);border-radius:6px;overflow:hidden}
  .progress span{display:block;height:100%;width:0%;background:linear-gradient(90deg,var(--red),#f6a3a1);
    animation:fill 1.1s ease forwards;border-radius:6px}
  @keyframes fill{to{width:100%}}
  .from{color:var(--muted);text-align:center;margin:0;font-size:.95rem}
  .from strong{color:var(--red)}

  /* ---------- App shell ---------- */
  #app{min-height:100vh;display:flex;flex-direction:column;max-width:960px;margin:0 auto;padding:24px}
  header{display:flex;align-items:center;justify-content:space-between}
  .brand{display:flex;align-items:center;gap:10px}
  .brand img{width:34px;height:34px}
  .brand .wordmark{font-size:1.2rem}
  .lang-wrap{position:relative}
  .lang{display:flex;align-items:center;gap:6px;color:var(--text);font-size:.95rem;
    background:none;border:none;cursor:pointer;font-family:inherit;padding:6px}
  .lang-menu{position:absolute;right:0;top:calc(100% + 6px);background:#fff;border-radius:12px;
    box-shadow:0 8px 24px rgba(0,0,0,.14);overflow-y:auto;max-height:280px;min-width:150px;z-index:10}
  .lang-menu button{display:block;width:100%;text-align:right;padding:10px 14px;border:none;
    background:#fff;cursor:pointer;font-size:.9rem;color:var(--text);font-family:inherit}
  .lang-menu button:hover{background:#fbeeee}

  main{flex:1;display:flex;flex-direction:column;align-items:center;text-align:center;padding-top:24px}
  main h2{font-weight:600;font-size:1.15rem;margin:0 0 6px}
  .result{display:flex;align-items:baseline;gap:10px;margin:6px 0}
  #mainSpeed{font-family:'Poppins',sans-serif;font-weight:800;font-size:clamp(3rem,12vw,5.5rem);line-height:1}
  .unit{color:var(--muted);font-weight:600;font-size:1.1rem}

  .play-btn{margin:14px 0 30px;width:60px;height:60px;border-radius:50%;border:2px solid var(--red);
    background:#fff;color:var(--red);font-size:1.3rem;cursor:pointer;box-shadow:0 6px 20px rgba(232,35,31,.18);
    display:flex;align-items:center;justify-content:center;transition:transform .15s ease}
  .play-btn:active{transform:scale(.94)}

  .cards{display:grid;grid-template-columns:repeat(3,1fr);gap:16px;width:100%;margin-bottom:16px}
  .card{background:var(--card);border-radius:var(--radius);padding:18px 14px;
    box-shadow:0 2px 10px rgba(0,0,0,.05);display:flex;flex-direction:column;align-items:center;gap:8px}
  .icon-circle{width:44px;height:44px;border-radius:50%;border:2px solid var(--red);
    display:flex;align-items:center;justify-content:center;color:var(--red)}
  .card .label{font-size:.72rem;color:var(--muted);font-weight:600;letter-spacing:.3px}
  .card .value{font-weight:700;color:var(--red);font-size:1.15rem}
  .card .value small{color:var(--muted);font-weight:500;font-size:.7rem}

  .retest-btn{margin-top:8px;background:var(--red);color:#fff;border:none;border-radius:12px;
    padding:14px 28px;font-weight:700;font-size:1rem;cursor:pointer;display:flex;align-items:center;
    gap:8px;box-shadow:0 8px 22px rgba(232,35,31,.28)}
  .retest-btn:active{transform:translateY(1px)}

  footer{text-align:right;color:var(--text);padding:18px 4px 4px;font-size:.9rem}
  footer strong{color:var(--red)}

  /* ---------- AEO/GEO: Answer capsule + FAQ ---------- */
  .intro-capsule{max-width:640px;color:var(--muted);font-size:.95rem;line-height:1.6;
    margin:10px auto 0;text-align:center}
  .faq{width:100%;max-width:960px;margin:44px auto 0;text-align:left;padding:0 24px}
  .faq:last-of-type{padding-bottom:24px}
  .faq h2{font-family:'Poppins',sans-serif;font-weight:700;font-size:1.25rem;color:var(--text);margin:0 0 8px}
  .faq-intro{color:var(--muted);font-size:.92rem;line-height:1.6;margin:0 0 20px;max-width:760px}
  .faq-item{background:var(--card);border-radius:var(--radius);padding:18px 20px;
    margin-bottom:14px;box-shadow:0 2px 10px rgba(0,0,0,.05)}
  .faq-item h3{font-size:1rem;color:var(--red);margin:0 0 8px;font-weight:700}
  .faq-item p{margin:0;color:var(--text);font-size:.92rem;line-height:1.6}

  @media(max-width:640px){
    .cards{grid-template-columns:1fr 1fr}
    .cards:last-of-type{grid-template-columns:1fr}
  }
  @media(max-width:420px){
    .cards{grid-template-columns:1fr}
    header{gap:8px;flex-wrap:wrap}
    .brand .wordmark{font-size:1rem}
    .lang{font-size:.85rem;padding:6px 4px}
    #app{padding:16px}
    .faq{padding:0 16px}
    .faq:last-of-type{padding-bottom:16px}
  }
  @media (prefers-reduced-motion: reduce){
    .progress span{animation:none;width:100%}
  }