:root {
    --bg: #0b0d12; --panel: #14171e; --panel2: #1c2029; --panel3: #232834;
    --border: #2a2f3b; --text: #e6eaf2; --dim: #8b94a7;
    --accent: #6ec6ff; --accent2: #8b7bff; --hot: #ff7043;
    --grad: linear-gradient(135deg, #6ec6ff, #8b7bff);
    --r: 12px;
  }
  * { box-sizing: border-box; margin: 0; }
  html, body { height: 100%; overflow: hidden; font-family: 'Segoe UI', Inter, system-ui, sans-serif; background: var(--bg); color: var(--text); }
  button { font-family: inherit; }

  /* ---- top bar ---- */
  #topbar {
    height: 52px; display: flex; align-items: center; gap: 10px; padding: 0 16px;
    background: var(--panel); border-bottom: 1px solid var(--border);
  }
  .brand { font-size: 16px; font-weight: 700; letter-spacing: .3px; margin-right: 14px; }
  .brand span { color: var(--accent); }
  .brand em { font-style: normal; font-weight: 400; color: var(--dim); font-size: 12px; margin-left: 6px; }
  .tbtn {
    background: var(--panel2); color: var(--text); border: 1px solid var(--border);
    border-radius: 8px; padding: 7px 13px; font-size: 12.5px; cursor: pointer;
  }
  .tbtn:hover { border-color: var(--accent); }
  .tbtn.primary { background: var(--grad); color: #0b0d12; border: none; font-weight: 600; }
  #coinPill {
    background: var(--panel2); border: 1px solid var(--border); border-radius: 16px;
    padding: 6px 14px; font-size: 13px; font-weight: 600;
  }

  /* ---- layout ---- */
  #main { display: flex; height: calc(100% - 52px - 28px); gap: 0; }

  /* left icon rail */
  #rail {
    width: 64px; background: var(--panel); border-right: 1px solid var(--border);
    display: flex; flex-direction: column; align-items: center; gap: 4px; padding: 10px 0; overflow-y: auto;
  }
  .rail-sep { width: 32px; height: 1px; background: var(--border); margin: 6px 0; flex: none; }
  .tool {
    width: 52px; height: 50px; display: flex; flex-direction: column; align-items: center; justify-content: center;
    gap: 2px; background: transparent; color: var(--dim); border: 1px solid transparent;
    border-radius: 10px; cursor: pointer; flex: none;
  }
  .tool i { font-style: normal; font-size: 16px; line-height: 1; }
  .tool b { font-weight: 500; font-size: 8.5px; letter-spacing: .2px; }
  .tool:hover { background: var(--panel2); color: var(--text); }
  .tool.active { background: var(--panel3); border-color: var(--accent); color: var(--accent); }

  /* control panel */
  #toolpanel {
    width: 268px; background: var(--panel); border-right: 1px solid var(--border);
    padding: 14px 12px; display: flex; flex-direction: column; gap: 10px; overflow-y: auto;
  }
  #toolpanel > h2 { font-size: 14px; font-weight: 600; padding: 0 2px 2px; }
  .upload-card {
    display: flex; gap: 12px; align-items: center; padding: 14px;
    border: 1.5px dashed var(--border); border-radius: var(--r); cursor: pointer;
    background: var(--panel2); transition: border-color .15s;
  }
  .upload-card:hover { border-color: var(--accent); }
  .upload-card .up-ico {
    width: 38px; height: 38px; border-radius: 10px; background: var(--panel3);
    display: flex; align-items: center; justify-content: center; font-size: 17px; flex: none;
  }
  .upload-card strong { font-size: 13px; }
  .upload-card span { font-size: 10.5px; color: var(--dim); line-height: 1.45; }
  .card {
    background: var(--panel2); border: 1px solid var(--border); border-radius: var(--r);
    padding: 12px; display: flex; flex-direction: column; gap: 9px;
  }
  .card h3 { font-size: 11px; text-transform: uppercase; letter-spacing: 1px; color: var(--dim); font-weight: 600; }
  .slider-row { font-size: 12px; color: var(--dim); }
  .slider-row label { display: flex; justify-content: space-between; margin-bottom: 5px; }
  .slider-row input[type=range] { width: 100%; accent-color: var(--accent); }
  .check-row { display: flex; gap: 8px; align-items: center; font-size: 12px; color: var(--text); }
  .btn-row { display: flex; gap: 8px; }
  .pbtn {
    flex: 1; background: var(--panel3); color: var(--text); border: 1px solid var(--border);
    border-radius: 8px; padding: 8px 10px; font-size: 12px; cursor: pointer; white-space: nowrap;
  }
  .pbtn:hover { border-color: var(--accent); }
  .pbtn.wide { width: 100%; flex: none; }
  .hint { font-size: 10.5px; color: var(--dim); line-height: 1.45; }
  .gen-btn {
    width: 100%; display: flex; align-items: center; justify-content: center; gap: 8px;
    background: var(--grad); color: #0b0d12; border: none; border-radius: 10px;
    padding: 11px; font-size: 13.5px; font-weight: 700; cursor: pointer;
  }
  .gen-btn:hover { filter: brightness(1.1); }
  .gen-btn[disabled] { opacity: .5; cursor: default; filter: none; }
  .gen-btn .cost { background: rgba(11,13,18,.22); border-radius: 12px; padding: 2px 9px; font-size: 11px; }
  .gen-btn.alt { background: var(--hot); }

  /* center */
  #centercol { flex: 1; display: flex; flex-direction: column; min-width: 0; padding: 10px; gap: 8px; }
  #viewport { flex: 1; min-height: 0; position: relative; border-radius: var(--r); overflow: hidden; border: 1px solid var(--border); }
  #viewport canvas { display: block; }
  #panelTabs {
    display: flex; gap: 4px; background: var(--panel2); border: 1px solid var(--border);
    border-radius: 10px; padding: 4px; flex: none;
  }
  .ptab {
    flex: 1; background: transparent; color: var(--dim); border: none; border-radius: 7px;
    padding: 7px; font-size: 12.5px; cursor: pointer; font-weight: 600;
  }
  .ptab:hover { color: var(--text); }
  .ptab.active { background: var(--panel3); color: var(--text); }
  #partsBar { display: flex; flex-direction: column; gap: 8px; }
  #partsBar .chip {
    display: flex; align-items: center; gap: 6px; padding: 5px 9px; border-radius: 16px;
    background: var(--panel2); border: 1px solid var(--border); font-size: 12.5px; cursor: pointer;
    white-space: nowrap; flex: none;
  }
  #partsBar .chip.active { border-color: var(--accent); }
  #partsBar .chip.multi { border-color: var(--hot); border-style: dashed; }
  #partsBar .chip .dot { width: 10px; height: 10px; border-radius: 50%; flex: none; }
  #partsBar .chip .dot + span { flex: 1; overflow: hidden; text-overflow: ellipsis; }
  .icon-btn {
    background: transparent; border: none; color: var(--dim); cursor: pointer;
    font-size: 13px; padding: 2px 3px; border-radius: 4px;
  }
  .icon-btn:hover { color: var(--text); background: var(--border); }

  /* right assets/history panel */
  #historyPanel {
    width: 252px; background: var(--panel); border-left: 1px solid var(--border);
    padding: 14px 12px; display: flex; flex-direction: column; gap: 10px; overflow-y: auto;
  }
  #historyPanel h2 { font-size: 11px; text-transform: uppercase; letter-spacing: 1px; color: var(--dim); font-weight: 600; }
  #historyList { display: grid; grid-template-columns: 1fr 1fr; gap: 8px; align-content: start; }
  .hist-card {
    background: var(--panel2); border: 1px solid var(--border); border-radius: 10px;
    padding: 6px; cursor: pointer; display: flex; flex-direction: column; gap: 4px;
  }
  .hist-card:hover, .hist-card.active { border-color: var(--accent); }
  .hist-card img { width: 100%; border-radius: 6px; display: block; background: #0b0d12; }
  .hist-card .hname { font-size: 11.5px; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
  .hist-card .hmeta { font-size: 9.5px; color: var(--dim); display: flex; justify-content: space-between; align-items: center; }

  /* status bar */
  #statusbar {
    height: 28px; display: flex; align-items: center; justify-content: space-between;
    padding: 0 16px; font-size: 11.5px; color: var(--dim);
    background: var(--panel); border-top: 1px solid var(--border);
  }

  /* toast, progress, modals */
  #toast {
    position: fixed; left: 50%; bottom: 48px; transform: translateX(-50%) translateY(20px);
    background: var(--panel2); border: 1px solid var(--border); color: var(--text);
    padding: 10px 18px; border-radius: 10px; font-size: 13px; opacity: 0; pointer-events: none;
    transition: all .25s; max-width: 70vw; box-shadow: 0 6px 24px rgba(0,0,0,.5); z-index: 60;
  }
  #toast.show { opacity: 1; transform: translateX(-50%) translateY(0); }
  #progress, #simplifyModal, #repairModal, #movePartModal, #buyModal {
    position: fixed; inset: 0; display: none; align-items: center; justify-content: center;
    background: rgba(6, 8, 12, .6); z-index: 50;
  }
  .pbox {
    background: var(--panel); border: 1px solid var(--border); border-radius: 14px;
    padding: 22px 28px; width: 340px; box-shadow: 0 12px 48px rgba(0,0,0,.55);
  }
  #simplifyModal .pbox, #repairModal .pbox, #movePartModal .pbox, #buyModal .pbox { width: 420px; }
  #simplifyModal h3, #repairModal h3, #movePartModal h3, #buyModal h3 { font-size: 15px; margin-bottom: 10px; }
  #simplifyModal p, #repairModal p, #movePartModal p, #buyModal p { font-size: 13px; color: var(--dim); line-height: 1.5; margin-bottom: 14px; }
  #progLabel { font-size: 13px; margin-bottom: 12px; color: var(--text); }
  .ptrack { height: 8px; background: var(--panel2); border-radius: 4px; overflow: hidden; }
  #progBar { height: 100%; width: 2%; border-radius: 4px; background: var(--grad); transition: width .18s ease; }
  .btn {
    background: var(--panel2); color: var(--text); border: 1px solid var(--border);
    border-radius: 8px; padding: 7px 13px; font-size: 13px; cursor: pointer;
  }
  .btn:hover { border-color: var(--accent); }
  .btn.primary { background: var(--grad); color: #0b0d12; border: none; font-weight: 600; }
  .btn.hot { background: var(--hot); color: #1a0e08; border: none; font-weight: 600; }

  /* login page */
  #loginPage {
    position: fixed; inset: 0; display: flex; align-items: center; justify-content: center;
    background: radial-gradient(1200px 700px at 50% 30%, #131720, #0b0d12 70%); z-index: 100;
  }
  .login-box {
    background: var(--panel); border: 1px solid var(--border); border-radius: 16px;
    padding: 36px 40px; width: 390px; text-align: center; box-shadow: 0 16px 60px rgba(0,0,0,.6);
  }
  .login-box h1 { font-size: 23px; margin-bottom: 8px; }
  .login-box h1 span { color: var(--accent); }
  .login-box p { font-size: 13px; color: var(--dim); margin-bottom: 18px; }