/* ── Neulis font face (loaded from local fonts/ folder if available) ── */
    @font-face {
      font-family: 'Neulis';
      src: url('fonts/Neulis-SemiBoldItalic.woff2') format('woff2'),
           url('fonts/Neulis-SemiBoldItalic.woff')  format('woff');
      font-weight: 600;
      font-style: italic;
      font-display: swap;
    }
    *{box-sizing:border-box;margin:0;padding:0;}
    :root{
      --masc:#3b82f6;--fem:#ec4899;--neut:#10b981;
      --bg:#0f172a;--card:#1e293b;--card2:#263347;
      --text:#f1f5f9;--sub:#94a3b8;--border:#334155;
      --correct:#22c55e;--wrong:#ef4444;--accent:#6366f1;
      --tab-h:56px;--safe-bottom:env(safe-area-inset-bottom,0px);
      --nav-float-h:60px;--nav-float-gap:8px;--sidebar-w:230px;
    }
    html,body{height:100%;overflow:hidden;background:var(--bg);color:var(--text);
      font-family:-apple-system,BlinkMacSystemFont,'Segoe UI',sans-serif;}

    /* ── App shell ── */
    #app{position:fixed;inset:0;display:flex;flex-direction:column;}
    .tab-pages{flex:1;position:relative;overflow:hidden;}
    .tab-page{position:absolute;inset:0;overflow-y:auto;
      transition:opacity .25s,transform .25s;
      padding-bottom:calc(var(--nav-float-h) + var(--nav-float-gap)*2 + var(--safe-bottom));}
    .tab-page.hidden{opacity:0;pointer-events:none;transform:translateY(8px);}

    /* ── Tab bar: floating pill (mobile & tablet, Apple-style) ── */
    .tabbar{position:fixed;left:50%;bottom:calc(var(--nav-float-gap) + var(--safe-bottom));
      transform:translateX(-50%);z-index:20;height:var(--nav-float-h);width:90%;max-width:none;
      background:rgba(30,41,59,.72);backdrop-filter:blur(24px);-webkit-backdrop-filter:blur(24px);
      border:1px solid rgba(255,255,255,.08);border-radius:999px;
      display:flex;align-items:center;gap:2px;padding:6px;
      box-shadow:0 10px 30px rgba(0,0,0,.4);}
    .tab{flex:1;width:auto;height:100%;display:flex;flex-direction:column;align-items:center;justify-content:center;
      gap:3px;cursor:pointer;-webkit-tap-highlight-color:transparent;border:none;background:none;
      border-radius:999px;color:var(--sub);font-size:.65rem;font-weight:600;letter-spacing:.02em;
      transition:color .15s,background .15s;padding:6px 0;}
    .tab svg{width:22px;height:22px;transition:transform .15s;}
    .tab img{transition:transform .15s;}
    .tab-label{display:none;}
    .tab.active{color:var(--text);background:rgba(255,255,255,.12);}
    .tab.active svg,.tab.active img{transform:scale(1.08);}
    .tab:active svg,.tab:active img{transform:scale(.9);}
    .tab-group{display:contents;}
    .tab-row{display:contents;}
    .tab-chevron{display:none;}
    .tab-subitems{display:none;}

    /* ── Desktop: side navigation ── */
    @media (min-width:1024px){
      #app{flex-direction:row;}
      .tab-pages{order:2;}
      .tab-page{padding-bottom:24px;}
      .tabbar{order:1;position:static;left:auto;bottom:auto;transform:none;z-index:auto;
        flex-shrink:0;width:var(--sidebar-w);height:100%;max-width:none;
        background:var(--bg);backdrop-filter:none;-webkit-backdrop-filter:none;box-shadow:none;
        border:none;border-right:1px solid var(--border);border-radius:0;
        flex-direction:column;align-items:stretch;justify-content:flex-start;gap:6px;
        padding:32px 14px;overflow-y:auto;}
      .tab{flex:none;width:100%;height:auto;flex-direction:row;justify-content:flex-start;
        gap:12px;padding:11px 14px;border-radius:12px;font-size:.88rem;}
      .tab-label{display:inline;}
      .tab.active{background:var(--card);}
      .tab-group{display:flex;flex-direction:column;gap:2px;}
      .tab-row{display:flex;align-items:center;gap:2px;}
      .tab-row .tab{flex:1;width:auto;}
      .tab-chevron{display:flex;flex:none;align-items:center;justify-content:center;
        width:30px;height:30px;border:none;background:none;color:var(--sub);
        cursor:pointer;border-radius:8px;-webkit-tap-highlight-color:transparent;
        transition:background .15s,color .15s;}
      .tab-chevron:hover{background:var(--card);color:var(--text);}
      .chev-icon{width:16px;height:16px;transition:transform .2s;}
      .tab-chevron.open .chev-icon{transform:rotate(180deg);}
      .tab-subitems{display:flex;flex-direction:column;gap:1px;margin:0 0 0 20px;
        padding-left:14px;border-left:1px solid var(--border);
        max-height:0;overflow:hidden;transition:max-height .25s ease,margin .25s ease;}
      .tab-subitems.open{max-height:400px;margin:2px 0 8px 20px;}
      .tab-subitem{display:flex;align-items:center;gap:9px;border:none;background:none;
        color:var(--sub);font-size:.82rem;font-weight:600;text-align:left;width:100%;
        padding:8px 10px;border-radius:9px;cursor:pointer;-webkit-tap-highlight-color:transparent;
        transition:color .15s,background .15s;}
      .tab-subitem-icon{font-size:.9rem;flex-shrink:0;}
      .tab-subitem:hover{background:var(--card);color:var(--text);}
      .tab-subitem.active{background:var(--card);color:var(--accent);}
    }

    /* ── Shared tab-page header ── */
    .page-header{max-width:480px;margin:0 auto;padding:52px 16px 0;
      font-size:1.4rem;font-weight:900;letter-spacing:-.01em;}

    /* ── Shared navbar ── */
    .navbar{width:100%;padding:52px 16px 12px;display:flex;align-items:center;gap:12px;
      position:sticky;top:0;background:var(--bg);z-index:10;border-bottom:1px solid var(--border);}
    .nav-back{background:none;border:none;color:var(--accent);font-size:.95rem;font-weight:600;
      cursor:pointer;display:flex;align-items:center;gap:3px;padding:4px 0;
      -webkit-tap-highlight-color:transparent;}
    .nav-back svg{width:18px;height:18px;}
    .navbar-title{flex:1;font-size:1rem;font-weight:700;text-align:center;}
    .navbar-right{width:60px;display:flex;justify-content:flex-end;}

    /* ── Push screens ── */
    .push-screen{position:fixed;inset:0;z-index:50;background:var(--bg);
      transform:translateX(100%);opacity:0;
      transition:transform .35s cubic-bezier(.4,0,.2,1),opacity .35s;
      display:flex;flex-direction:column;align-items:center;overflow-y:auto;
      padding-bottom:32px;}
    .push-screen.open{transform:translateX(0);opacity:1;}