:root{
    --bg:#05100E; --panel:#0A1F1A; --panel-raised:#0D2620;
    --line:#1C3A32; --line-bright:#2A5548;
    --text:#EAF3EF; --text-dim:#7FA69C; --text-dimmer:#4C6B63;
    --amber:#FF8A3D; --amber-dim:#8A4E24;
    --phosphor:#39FF88; --phosphor-dim:#123D28;
    --danger:#FF5C5C; --radius:3px;
    --sidebar-w:250px;
  }
  *{margin:0;padding:0;box-sizing:border-box;}
  body{background:var(--bg);color:var(--text);font-family:'IBM Plex Mono',monospace;line-height:1.6;-webkit-font-smoothing:antialiased;}
  h1,h2,h3,h4{font-family:'Space Grotesk',sans-serif;}
  button,input,select,textarea{font-family:inherit;color:inherit;}
  a{color:inherit;}
  ::-webkit-scrollbar{width:8px;height:8px;}
  ::-webkit-scrollbar-thumb{background:var(--line-bright);border-radius:4px;}
  button:focus-visible, a:focus-visible, input:focus-visible, select:focus-visible{outline:2px solid var(--amber);outline-offset:2px;}
  @media (prefers-reduced-motion: reduce){*{animation-duration:.001s !important;transition-duration:.001s !important;}}

  /* ---- shell ---- */
  #shell{display:flex;min-height:100vh;}
  #sidebar{
    width:var(--sidebar-w);flex-shrink:0;border-right:1px solid var(--line);
    background:var(--panel);position:sticky;top:0;height:100vh;overflow-y:auto;
    display:flex;flex-direction:column;
  }
  .brand{display:flex;align-items:center;gap:10px;padding:20px 18px;border-bottom:1px solid var(--line);font-family:'Space Grotesk',sans-serif;font-weight:700;font-size:16px;}
  .brand-dot{width:9px;height:9px;border-radius:50%;background:var(--phosphor);box-shadow:0 0 8px var(--phosphor);flex-shrink:0;}
  .nav-cat{padding:16px 18px 6px;font-size:10px;letter-spacing:.12em;text-transform:uppercase;color:var(--text-dimmer);}
  .nav-item{
    display:flex;align-items:center;gap:10px;padding:9px 18px;font-size:12.5px;color:var(--text-dim);
    cursor:pointer;border-left:2px solid transparent;
  }
  .nav-item:hover{color:var(--text);background:rgba(255,255,255,0.02);}
  .nav-item.active{color:var(--phosphor);border-left-color:var(--phosphor);background:rgba(57,255,136,0.05);}
  .nav-item.active .nav-icon{color:var(--phosphor);}
  .nav-icon{width:18px;text-align:center;flex-shrink:0;display:inline-flex;color:var(--text-dimmer);}
  .nav-item:hover .nav-icon{color:var(--text);}

  #main{flex:1;min-width:0;}
  .topbar{
    display:none;justify-content:space-between;align-items:center;padding:14px 18px;
    border-bottom:1px solid var(--line);background:rgba(5,16,14,0.92);position:sticky;top:0;z-index:40;
  }
  #menuBtn{background:none;border:1px solid var(--line-bright);color:var(--text);padding:7px 12px;border-radius:var(--radius);font-size:16px;cursor:pointer;}

  .content{max-width:980px;margin:0 auto;padding:36px 28px 80px;}

  /* ---- ad slot ---- */
  .ad-slot{border:1px dashed var(--line-bright);border-radius:var(--radius);padding:10px;display:flex;align-items:center;justify-content:center;min-height:90px;color:var(--text-dimmer);font-size:11px;letter-spacing:.08em;text-transform:uppercase;margin:28px 0;}

  /* ---- home ---- */
  .hero-home{margin-bottom:34px;}
  .eyebrow{color:var(--amber);font-size:12px;letter-spacing:.14em;text-transform:uppercase;display:flex;align-items:center;gap:10px;margin-bottom:16px;}
  .eyebrow::before{content:"";width:22px;height:1px;background:var(--amber);}
  .hero-home h1{font-size:clamp(28px,4.4vw,42px);font-weight:700;line-height:1.1;letter-spacing:-.01em;max-width:640px;}
  .hero-home h1 em{color:var(--phosphor);font-style:normal;}
  .hero-home p{margin-top:16px;color:var(--text-dim);font-size:14.5px;max-width:540px;}

  .cat-block{margin-top:38px;}
  .cat-title{font-size:11px;letter-spacing:.12em;text-transform:uppercase;color:var(--text-dimmer);margin-bottom:14px;display:flex;align-items:center;gap:10px;}
  .cat-title::after{content:"";flex:1;height:1px;background:var(--line);}
  .tool-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(210px,1fr));gap:12px;}
  .tool-card{
    border:1px solid var(--line);background:var(--panel);border-radius:var(--radius);padding:16px;
    cursor:pointer;transition:border-color .15s,background .15s,transform .1s;
  }
  .tool-card:hover{border-color:var(--phosphor);background:var(--panel-raised);transform:translateY(-1px);}
  .tool-card:hover .ti{color:var(--phosphor);}
  .tool-card .ti{color:var(--amber);margin-bottom:12px;display:inline-flex;transition:color .15s;}
  .tool-card h3{font-size:13.5px;font-weight:600;margin-bottom:5px;}
  .tool-card p{font-size:11.5px;color:var(--text-dim);}

  /* ---- tool view chrome ---- */
  .tool-view{display:none;}
  .tool-view.active{display:block;}
  .tool-head{margin-bottom:26px;}
  .back-link{font-size:11.5px;color:var(--text-dim);cursor:pointer;display:inline-flex;align-items:center;gap:6px;margin-bottom:16px;}
  .back-link:hover{color:var(--amber);}
  .tool-head h2{font-size:24px;font-weight:600;display:flex;align-items:center;gap:12px;}
  .thead-icon{display:inline-flex;color:var(--phosphor);flex-shrink:0;}
  .tool-head p{color:var(--text-dim);font-size:13px;margin-top:6px;max-width:560px;}

  .panel{border:1px solid var(--line);background:var(--panel);border-radius:var(--radius);padding:22px;margin-bottom:16px;}
  .panel-row{display:flex;gap:14px;flex-wrap:wrap;align-items:center;}
  .field{display:flex;flex-direction:column;gap:6px;}
  .field label{font-size:11px;color:var(--text-dimmer);text-transform:uppercase;letter-spacing:.06em;}
  input[type=text],input[type=number],input[type=date],input[type=password],select,textarea{
    background:#020A08;border:1px solid var(--line-bright);color:var(--text);padding:9px 11px;border-radius:var(--radius);font-size:13px;
  }
  textarea{resize:vertical;min-height:100px;width:100%;}
  input[type=range]{accent-color:var(--phosphor);}

  .btn{background:transparent;border:1px solid var(--line-bright);color:var(--text);padding:10px 18px;border-radius:var(--radius);font-size:12.5px;cursor:pointer;letter-spacing:.03em;transition:border-color .15s,color .15s;}
  .btn:hover{border-color:var(--amber);color:var(--amber);}
  .btn.primary{border-color:var(--phosphor);color:var(--phosphor);}
  .btn.primary:hover{background:rgba(57,255,136,0.08);}
  .btn:disabled{opacity:.4;cursor:not-allowed;}

  .readout{font-family:'IBM Plex Mono',monospace;font-size:13px;color:var(--phosphor);}
  .stat-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(140px,1fr));gap:14px;}
  .stat-box{border:1px solid var(--line);border-radius:var(--radius);padding:14px;background:#04120F;}
  .stat-box .label{font-size:10px;color:var(--text-dimmer);text-transform:uppercase;letter-spacing:.06em;margin-bottom:6px;}
  .stat-box .val{font-size:18px;color:var(--phosphor);font-weight:600;}

  .note{font-size:11.5px;color:var(--text-dimmer);margin-top:10px;line-height:1.6;}
  .warn{font-size:11.5px;color:var(--amber);margin-top:10px;}

  canvas{max-width:100%;}
  video{max-width:100%;border-radius:var(--radius);border:1px solid var(--line);background:#000;}

  .grid2{display:grid;grid-template-columns:1fr 1fr;gap:14px;}
  @media (max-width:640px){.grid2{grid-template-columns:1fr;}}

  /* speaker dial */
  .dial-btn{width:120px;height:120px;border-radius:50%;border:2px solid var(--line-bright);background:radial-gradient(circle at 35% 30%,#123028,#071713);color:var(--text);font-family:'Space Grotesk',sans-serif;font-weight:600;font-size:13px;cursor:pointer;display:flex;align-items:center;justify-content:center;text-align:center;transition:border-color .15s,box-shadow .15s;}
  .dial-btn.running{border-color:var(--phosphor);box-shadow:0 0 22px rgba(57,255,136,.25);animation:pulse 1.6s ease-in-out infinite;}
  @keyframes pulse{0%,100%{box-shadow:0 0 14px rgba(57,255,136,.18);}50%{box-shadow:0 0 28px rgba(57,255,136,.34);}}

  /* screen test overlay */
  #screenTestOverlay{position:fixed;inset:0;z-index:200;display:none;align-items:center;justify-content:center;cursor:pointer;}
  #screenTestOverlay .hint{position:absolute;bottom:24px;left:0;right:0;text-align:center;color:#888;font-family:'IBM Plex Mono',monospace;font-size:12px;}

  /* touch test */
  #touchGrid{display:grid;gap:2px;background:var(--line);border:1px solid var(--line);}
  .touch-cell{background:#020A08;aspect-ratio:1;transition:background .1s;}
  .touch-cell.hit{background:var(--phosphor);}

  /* password strength */
  .strength-bar{height:5px;background:var(--line);border-radius:4px;overflow:hidden;margin-top:8px;}
  .strength-fill{height:100%;width:0%;transition:width .2s,background .2s;}

  .calc-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:8px;max-width:320px;}
  .calc-btn{padding:16px 0;border:1px solid var(--line-bright);background:var(--panel-raised);border-radius:var(--radius);font-size:16px;cursor:pointer;}
  .calc-btn:hover{border-color:var(--amber);}
  .calc-btn.op{color:var(--amber);}
  .calc-display{font-size:30px;text-align:right;padding:16px;background:#020A08;border:1px solid var(--line);border-radius:var(--radius);margin-bottom:10px;word-break:break-all;font-family:'Space Grotesk',sans-serif;}

  footer{border-top:1px solid var(--line);padding:26px 28px;font-size:11px;color:var(--text-dimmer);display:flex;justify-content:space-between;flex-wrap:wrap;gap:10px;}

  #sidebarBackdrop{display:none;}

  @media (max-width:860px){
    #sidebar{position:fixed;left:-280px;top:0;z-index:100;transition:left .2s;width:260px;box-shadow:0 0 40px rgba(0,0,0,.5);}
    #sidebar.open{left:0;}
    #sidebarBackdrop.open{display:block;position:fixed;inset:0;background:rgba(0,0,0,.5);z-index:90;}
    .topbar{display:flex;}
    .content{padding:24px 18px 60px;}
  }


  /* ---- multi-page adaptions ---- */
  .nav-item a{display:block;flex:1;color:inherit;text-decoration:none;}
  .nav-item a:hover{color:inherit;}
  section[id^=view-]{display:block;}
  .tool-longdesc{font-size:12.5px;color:var(--text-dimmer);max-width:620px;margin-top:10px;line-height:1.6;}
  .page-head{margin-bottom:26px;}
  .page-head h1{font-size:30px;font-weight:700;letter-spacing:-.01em;}
  .rich-body{font-size:13.5px;color:var(--text-dim);line-height:1.8;}
  .rich-body h2,.rich-body h3{margin:18px 0 8px;color:var(--text);}
  .rich-body p{margin-bottom:12px;}
  .rich-body a{color:var(--phosphor);}
  .rich-body ul,.rich-body ol{margin:0 0 12px 20px;}
  .rich-body blockquote{border-left:2px solid var(--line-bright);padding-left:14px;margin:0 0 12px;color:var(--text-dimmer);}
  .rich-body img{max-width:100%;border-radius:var(--radius);}