:root{
    --bg1:#03080a;
    --bg2:#061410;
    --green:#39ff88;
    --green-soft:#a8ffce;
    --green-dim:#0f6b45;
    --gold:#ffcf4d;
    --red:#ff5f6d;
    --panel:#081712;
    --panel-line:rgba(57,255,136,0.22);
    --text:#e7fbf1;
    --text-dim:#7fa898;
  }
  *{ box-sizing:border-box; -webkit-tap-highlight-color:transparent; }
  html,body{
    margin:0; padding:0; width:100%; height:100%;
    background:var(--bg1);
    color:var(--text);
    font-family:'Vazirmatn', sans-serif;
    overscroll-behavior:none;
    overflow:hidden;
    position:fixed; inset:0;
  }
  .num{ font-family:'Orbitron', sans-serif; }
  button{ font-family:inherit; border:none; cursor:pointer; }
  button:focus-visible{ outline:2px solid var(--green-soft); outline-offset:2px; }

  #gameCanvas{
    position:fixed; inset:0;
    width:100%; height:100%;
    display:block;
    touch-action:none;
    background:radial-gradient(ellipse at 50% 0%, #0b2318 0%, var(--bg2) 45%, var(--bg1) 100%);
  }

  /* ---------- HUD ---------- */
  #hud{
    position:fixed; top:0; left:0; right:0;
    padding:calc(10px + env(safe-area-inset-top)) 14px 0;
    display:none;
    justify-content:space-between;
    align-items:flex-start;
    pointer-events:none;
    z-index:5;
  }
  #hud.visible{ display:flex; }
  .hud-block{
    background:rgba(8,23,18,0.6);
    border:1px solid var(--panel-line);
    border-radius:12px;
    padding:8px 12px;
    backdrop-filter:blur(6px);
    pointer-events:auto;
  }
  .hud-left{ display:flex; flex-direction:column; gap:4px; min-width:110px; }
  .hud-score .label{ font-size:0.65rem; color:var(--text-dim); letter-spacing:0.5px; }
  .hud-score .val{ font-size:1.25rem; font-weight:700; color:var(--green-soft); line-height:1.1; }
  .hud-sub{ font-size:0.68rem; color:var(--text-dim); display:flex; gap:10px; }
  .hud-sub b{ color:var(--gold); font-weight:700; }

  .hud-right{ display:flex; flex-direction:column; align-items:flex-end; gap:8px; }
  .hud-right-row{ display:flex; gap:8px; }
  .icon-btn{
    width:40px; height:40px; border-radius:10px;
    background:rgba(8,23,18,0.6);
    border:1px solid var(--panel-line);
    color:var(--text);
    display:flex; align-items:center; justify-content:center;
    font-size:1.05rem;
    pointer-events:auto;
    backdrop-filter:blur(6px);
  }
  .icon-btn.muted{ color:var(--red); }
  .mode-toggle{
    padding:8px 14px; border-radius:10px;
    background:rgba(8,23,18,0.6);
    border:1px solid var(--panel-line);
    color:var(--green-soft);
    font-size:0.78rem; font-weight:700;
    pointer-events:auto;
    backdrop-filter:blur(6px);
    display:flex; align-items:center; gap:6px;
    white-space:nowrap;
  }
  .mode-toggle.ai-active{
    border-color:var(--gold);
    color:var(--gold);
  }
  .ai-dot{
    width:7px; height:7px; border-radius:50%;
    background:currentColor;
  }
  .ai-dot.pulse{ animation:pulseDot 1.1s ease-in-out infinite; }
  @keyframes pulseDot{ 0%,100%{ opacity:0.4; } 50%{ opacity:1; } }

  /* ---------- D-pad ---------- */
  #dpad{
    direction:ltr;
    position:fixed;
    right:calc(14px + env(safe-area-inset-right));
    bottom:calc(18px + env(safe-area-inset-bottom));
    width:132px; height:132px;
    display:grid;
    grid-template-columns:repeat(3,1fr);
    grid-template-rows:repeat(3,1fr);
    gap:4px;
    z-index:5;
    opacity:0.9;
    transition:opacity .2s;
  }
  #dpad.dimmed{ opacity:0.35; }
  .dpad-btn{
    background:rgba(8,23,18,0.55);
    border:1px solid var(--panel-line);
    border-radius:10px;
    color:var(--green-soft);
    font-size:1.1rem;
    display:flex; align-items:center; justify-content:center;
    pointer-events:auto;
  }
  .dpad-btn:active{ background:rgba(57,255,136,0.22); }
  .dpad-up{ grid-column:2; grid-row:1; }
  .dpad-left{ grid-column:1; grid-row:2; }
  .dpad-right{ grid-column:3; grid-row:2; }
  .dpad-down{ grid-column:2; grid-row:3; }

  /* ---------- overlays ---------- */
  .overlay{
    position:fixed; inset:0;
    display:flex; align-items:center; justify-content:center;
    padding:20px; z-index:10;
    background:radial-gradient(ellipse at 50% 30%, rgba(57,255,136,0.06), transparent 60%), rgba(3,8,10,0.74);
    backdrop-filter:blur(3px);
    opacity:1; transition:opacity .25s ease;
  }
  .overlay.hide{ opacity:0; pointer-events:none; }
  .overlay[hidden]{ display:none; }

  .card{
    width:min(92vw, 420px);
    max-height:88vh; overflow-y:auto;
    background:linear-gradient(180deg, var(--panel), #051009);
    border:1px solid var(--panel-line);
    border-radius:20px;
    padding:26px 24px 24px;
    box-shadow:0 25px 60px rgba(0,0,0,0.55), 0 0 40px rgba(57,255,136,0.06);
    text-align:center;
  }
  .title-row{ display:flex; align-items:center; justify-content:center; gap:10px; margin-bottom:4px; }
  .snake-glyph{ width:30px; height:30px; }
  .card h1{
    font-family:'Orbitron', sans-serif; font-weight:900; font-size:1.45rem; margin:0;
    letter-spacing:1px;
    background:linear-gradient(90deg, var(--green-soft), var(--green));
    -webkit-background-clip:text; background-clip:text; color:transparent;
  }
  .card .subtitle{ font-size:0.83rem; color:var(--text-dim); margin:2px 0 16px; }

  .best-row{ display:flex; justify-content:center; gap:22px; margin-bottom:16px; flex-wrap:wrap; }
  .best-item .label{ font-size:0.66rem; color:var(--text-dim); }
  .best-item .val{ font-family:'Orbitron', sans-serif; font-size:1.1rem; font-weight:700; color:var(--gold); }

  .section-title{
    font-size:0.75rem; font-weight:700; color:var(--green-soft);
    text-align:right; margin:14px 0 8px;
  }
  .choice-row{ display:flex; gap:8px; }
  .btn{
    flex:1; padding:11px 8px; border-radius:11px;
    font-weight:700; font-size:0.85rem;
    background:rgba(255,255,255,0.04);
    color:var(--text); border:1px solid var(--panel-line);
    transition:all .15s;
  }
  .btn:active{ transform:scale(0.96); }
  .btn.primary{
    background:linear-gradient(90deg, var(--green), var(--green-soft));
    color:#04150c; border-color:transparent;
  }
  .btn.wide{ width:100%; padding:15px; font-size:1rem; margin-top:4px; }
  .btn.ghost{ background:transparent; }

  .mode-cards{ display:flex; flex-direction:column; gap:10px; }
  .mode-card{
    display:flex; align-items:center; gap:12px;
    padding:13px 14px; border-radius:13px;
    background:rgba(255,255,255,0.03);
    border:1px solid var(--panel-line);
    color:var(--text-dim); text-align:right; width:100%;
  }
  .mode-card .icon{ flex:none; font-size:1.3rem; }
  .mode-card b{ display:block; color:var(--text); font-size:0.92rem; }
  .mode-card small{ font-size:0.75rem; opacity:0.85; }
  .mode-card.active{
    border-color:var(--green);
    background:linear-gradient(90deg, rgba(57,255,136,0.16), rgba(57,255,136,0.04));
  }
  .mode-card.active b{ color:var(--green-soft); }

  .toggle-row{
    display:flex; align-items:center; justify-content:space-between;
    padding:10px 12px; border-radius:11px;
    background:rgba(255,255,255,0.03);
    border:1px solid var(--panel-line);
    font-size:0.82rem; color:var(--text-dim);
    margin-top:10px;
  }
  .switch{
    width:40px; height:22px; border-radius:12px;
    background:rgba(255,255,255,0.1);
    position:relative; flex:none;
    border:1px solid var(--panel-line);
  }
  .switch .knob{
    position:absolute; top:2px; right:2px;
    width:16px; height:16px; border-radius:50%;
    background:var(--text-dim);
    transition:all .18s;
  }
  .switch.on{ background:rgba(57,255,136,0.25); border-color:var(--green); }
  .switch.on .knob{ right:20px; background:var(--green); }

  .stack{ display:flex; flex-direction:column; gap:10px; margin-top:16px; }

  .go-score{ font-family:'Orbitron', sans-serif; font-size:2.3rem; font-weight:900; color:var(--green-soft); margin:6px 0 2px; }
  .go-new-best{ font-size:0.8rem; color:var(--gold); font-weight:700; margin-bottom:10px; min-height:18px; }
  .go-stats{ display:flex; justify-content:center; gap:18px; margin-bottom:6px; flex-wrap:wrap; }
  .go-stats .item{ font-size:0.72rem; color:var(--text-dim); }
  .go-stats .item b{ display:block; color:var(--green-soft); font-family:'Orbitron', sans-serif; font-size:1rem; }

  .toast{
    position:fixed; top:14%; left:50%; transform:translate(-50%,-10px);
    font-family:'Orbitron', sans-serif; font-weight:800;
    font-size:1rem; color:var(--gold);
    background:rgba(8,23,18,0.75); border:1px solid var(--gold);
    padding:8px 18px; border-radius:30px;
    opacity:0; z-index:6; pointer-events:none;
    text-shadow:0 0 10px rgba(255,207,77,0.6);
  }
  .toast.show{ animation:toastPop 1.3s ease forwards; }
  @keyframes toastPop{
    0%{ opacity:0; transform:translate(-50%,0); }
    18%{ opacity:1; transform:translate(-50%,-10px); }
    80%{ opacity:1; }
    100%{ opacity:0; transform:translate(-50%,-24px); }
  }

  .portal-back {
    position: fixed;
    top: max(10px, env(safe-area-inset-top));
    right: 12px;
    z-index: 30;
    padding: 6px 14px;
    border-radius: 999px;
    background: rgba(8, 23, 18, 0.72);
    border: 1px solid var(--panel-line);
    color: var(--green-soft);
    font-size: 0.78rem;
    font-weight: 600;
    text-decoration: none;
    backdrop-filter: blur(8px);
  }

  @media (prefers-reduced-motion: reduce){
    *{ animation-duration:0.001ms !important; transition-duration:0.001ms !important; }
  }