:root {
      --bg:      #0b0f1a;
      --panel:   #141a2b;
      --panel2:  #1a2236;
      --accent:  #7c5cff;
      --accent2: #00d4ff;
      --success: #28d99e;
      --warning: #ffb454;
      --danger:  #ff5e7c;
      --text:    #e6ecff;
      --muted:   #8a93b3;
      --border:  #1e293b;
    }

    *, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

    html, body {
      height: 100vh;
      overflow: hidden;
      background: var(--bg);
      color: var(--text);
      font-family: 'Inter', system-ui, sans-serif;
      font-size: 14px;
      line-height: 1.5;
    }

    body {
      display: flex;
      flex-direction: column;
    }

    /* ── Header ── */
    header {
      display: flex;
      align-items: center;
      justify-content: space-between;
      padding: 0.75rem 1.25rem;
      background: var(--panel);
      border-bottom: 1px solid var(--border);
      position: sticky;
      top: 0;
      z-index: 100;
    }

    .header-left { display: flex; align-items: center; gap: 0.75rem; }

    .header-title {
      font-size: 1.25rem;
      font-weight: 700;
      background: linear-gradient(135deg, var(--accent), var(--accent2));
      background-size: 200% 200%;
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      background-clip: text;
      animation: gradShift 4s ease infinite;
    }

    @keyframes gradShift {
      0%   { background-position: 0% 50%; }
      50%  { background-position: 100% 50%; }
      100% { background-position: 0% 50%; }
    }

    .pill {
      display: inline-flex;
      align-items: center;
      gap: 0.3rem;
      padding: 0.2rem 0.65rem;
      border-radius: 50px;
      font-size: 0.75rem;
      font-weight: 600;
      border: 1px solid transparent;
    }

    .pill-conn           { background: #0f1f14; border-color: var(--success); color: var(--success); }
    .pill-conn.reconnect { background: #1f1a0a; border-color: var(--warning); color: var(--warning); }
    .pill-conn.offline   { background: #1f0a0e; border-color: var(--danger);  color: var(--danger);  }
    .pill-env            { background: #12102b; border-color: var(--accent);  color: var(--accent);  }
    .pill-ver            { background: #0a1820; border-color: var(--accent2); color: var(--accent2); }
    .pill-eval           { background: #051822; border-color: var(--accent2); color: var(--accent2); font-weight: 700; letter-spacing: 0.08em; animation: evalPulse 1.2s ease-in-out infinite; }
    @keyframes evalPulse { 0%, 100% { opacity: 1; } 50% { opacity: 0.55; } }

    .header-pills { display: flex; align-items: center; gap: 0.5rem; flex-wrap: wrap; }

    /* ── Layout ── */
    .app-body {
      flex: 1;
      display: grid;
      grid-template-columns: 28% 1fr;
      grid-template-rows: 1fr auto;
      gap: 0.5rem;
      padding: 0.5rem;
      min-height: 0;
    }

    .left-col {
      grid-column: 1;
      grid-row: 1;
      display: flex;
      flex-direction: column;
      gap: 0.5rem;
      min-height: 0;
    }

    .right-col {
      grid-column: 2;
      grid-row: 1;
      display: flex;
      flex-direction: column;
      gap: 0.5rem;
      min-height: 0;
      overflow-y: auto;
    }

    .controls-bar-row {
      grid-column: 1 / -1;
      grid-row: 2;
    }

    /* Runs section fills remaining left-col space */
    #section-runs {
      flex: 1;
      min-height: 0;
      display: flex;
      flex-direction: column;
    }

    #runsList {
      flex: 1;
      overflow-y: auto;
      min-height: 0;
      padding: 0.5rem;
    }

    /* ── Panel ── */
    .panel {
      background: var(--panel);
      border: 1px solid var(--border);
      border-radius: 10px;
      overflow: hidden;
    }

    .panel-header {
      display: flex;
      align-items: center;
      justify-content: space-between;
      padding: 0.6rem 0.9rem;
      border-bottom: 1px solid var(--border);
      font-weight: 600;
      font-size: 0.8rem;
      text-transform: uppercase;
      letter-spacing: 0.05em;
      color: var(--muted);
    }

    .panel-body { padding: 0.75rem; }

    /* ── Canvas ── */
    .canvas-wrap {
      position: relative;
      overflow: hidden;
      flex: 0 0 auto;
      height: 46vh;
    }

    #simCanvas {
      display: block;
      width: 100%;
      height: 100%;
      cursor: crosshair;
    }

    .canvas-hud {
      position: absolute;
      top: 0.5rem;
      left: 0.5rem;
      display: flex;
      gap: 0.5rem;
      flex-wrap: wrap;
      pointer-events: none;
    }



    .hud-chip {
      background: rgba(11,15,26,0.8);
      border: 1px solid var(--border);
      border-radius: 5px;
      padding: 0.15rem 0.5rem;
      font-size: 0.7rem;
      font-weight: 600;
      color: var(--text);
      backdrop-filter: blur(4px);
    }

    /* ── Controls bar ── */
    .controls-bar {
      display: flex;
      align-items: center;
      flex-wrap: wrap;
      gap: 0.75rem;
      padding: 0.75rem;
      background: var(--panel);
      border: 1px solid var(--border);
      border-radius: 10px;
    }

    .ctrl-btns { display: flex; gap: 0.4rem; flex-wrap: wrap; }

    .btn {
      display: inline-flex;
      align-items: center;
      gap: 0.3rem;
      padding: 0.3rem 0.75rem;
      border-radius: 7px;
      border: 1px solid transparent;
      font-size: 0.78rem;
      font-weight: 600;
      cursor: pointer;
      min-height: 32px;
      transition: opacity 0.15s, transform 0.1s;
      white-space: nowrap;
    }
    .btn:active { transform: scale(0.96); }
    .btn:disabled { opacity: 0.35; cursor: not-allowed; }

    .btn-success { background: #0d3326; border-color: var(--success); color: var(--success); }
    .btn-success:hover:not(:disabled) { background: #124030; }
    .btn-warning { background: #2e1f05; border-color: var(--warning); color: var(--warning); }
    .btn-warning:hover:not(:disabled) { background: #3a2808; }
    .btn-accent  { background: #180e3a; border-color: var(--accent);  color: var(--accent); }
    .btn-accent:hover:not(:disabled)  { background: #231550; }
    .btn-accent2 { background: #051822; border-color: var(--accent2); color: var(--accent2); }
    .btn-accent2:hover:not(:disabled) { background: #07202e; }
    .btn-danger  { background: #2e0a12; border-color: var(--danger);  color: var(--danger); }
    .btn-danger:hover:not(:disabled)  { background: #3d0f1a; }
    .btn-muted   { background: #14192a; border-color: var(--muted);   color: var(--muted); }
    .btn-muted:hover:not(:disabled)   { background: #1c2438; }
    .btn-sm { padding: 0.25rem 0.6rem; min-height: 30px; font-size: 0.75rem; }

    .ctrl-sliders {
      display: flex;
      align-items: center;
      gap: 1rem;
      flex-wrap: wrap;
    }

    .slider-group {
      display: flex;
      align-items: center;
      gap: 0.4rem;
      font-size: 0.75rem;
      color: var(--muted);
    }

    .slider-group label { white-space: nowrap; }

    input[type=range] {
      -webkit-appearance: none;
      appearance: none;
      width: 90px;
      height: 4px;
      background: var(--border);
      border-radius: 2px;
      outline: none;
    }
    input[type=range]::-webkit-slider-thumb {
      -webkit-appearance: none;
      width: 14px;
      height: 14px;
      border-radius: 50%;
      background: var(--accent2);
      cursor: pointer;
    }

    .ctrl-stats {
      display: flex;
      gap: 1rem;
      font-size: 0.75rem;
      color: var(--muted);
      margin-left: auto;
      flex-wrap: wrap;
    }

    .ctrl-stats span { display: flex; gap: 0.2rem; align-items: center; }


    input[type=checkbox] {
      accent-color: var(--accent2);
      width: 14px;
      height: 14px;
    }

    /* ── Runs sidebar ── */
    .run-item {
      display: flex;
      align-items: center;
      gap: 0.5rem;
      padding: 0.5rem 0.75rem;
      border-bottom: 1px solid var(--border);
      cursor: pointer;
      transition: background 0.15s;
    }
    .run-item:last-child { border-bottom: none; }
    .run-item:hover { background: var(--panel2); }
    .run-item.active { background: #180e3a; border-left: 2px solid var(--accent); }

    .run-name { font-weight: 600; font-size: 0.8rem; flex: 1; min-width: 0; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }

    .run-meta { font-size: 0.7rem; color: var(--muted); }

    .status-badge {
      font-size: 0.65rem;
      font-weight: 700;
      padding: 0.1rem 0.4rem;
      border-radius: 4px;
      text-transform: uppercase;
      white-space: nowrap;
    }
    .s-idle      { background: #1a2236; color: var(--muted); }
    .s-training  { background: #0d3326; color: var(--success); }
    .s-paused    { background: #2e1f05; color: var(--warning); }
    .s-completed { background: #0a1820; color: var(--accent2); }
    .s-failed    { background: #2e0a12; color: var(--danger); }

    .run-actions { display: flex; gap: 0.25rem; }

    .runs-empty {
      padding: 1.5rem;
      text-align: center;
      color: var(--muted);
      font-size: 0.8rem;
    }

    /* ── Charts ── */
    .charts-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 0.5rem;
    }

    .chart-card {
      background: var(--panel);
      border: 1px solid var(--border);
      border-radius: 8px;
      padding: 0.5rem;
      position: relative;
    }

    .chart-card canvas { display: block; width: 100% !important; height: 160px !important; }

    .chart-info-btn {
      position: absolute;
      top: 0.4rem;
      right: 0.4rem;
      width: 18px;
      height: 18px;
      border-radius: 50%;
      background: var(--panel2);
      border: 1px solid var(--border);
      color: var(--muted);
      font-size: 10px;
      font-weight: 700;
      cursor: pointer;
      display: flex;
      align-items: center;
      justify-content: center;
      z-index: 10;
      user-select: none;
      transition: background 0.15s, color 0.15s;
    }
    .chart-info-btn:hover { background: var(--accent); color: #fff; border-color: var(--accent); }

    .chart-tooltip {
      display: none;
      position: fixed;
      z-index: 200;
      max-width: 360px;
      max-height: 70vh;
      overflow-y: auto;
      background: #1a2236;
      border: 1px solid var(--accent);
      border-radius: 10px;
      padding: 1rem 1.1rem;
      font-size: 12px;
      line-height: 1.6;
      color: var(--text);
      box-shadow: 0 8px 40px rgba(0,0,0,0.6);
      pointer-events: none;
    }
    .chart-tooltip.visible { display: block; }
    .chart-tooltip .tip-title { color: var(--accent2); font-size: 13px; font-weight: 700; display: block; margin-bottom: 0.55rem; border-bottom: 1px solid var(--border); padding-bottom: 0.4rem; }
    .chart-tooltip .tip-section { margin-bottom: 0.55rem; }
    .chart-tooltip .tip-label { color: var(--muted); font-size: 10px; text-transform: uppercase; letter-spacing: 0.05em; font-weight: 600; display: block; margin-bottom: 0.15rem; }
    .chart-tooltip .tip-good { color: var(--success); font-weight: 600; }
    .chart-tooltip .tip-bad  { color: var(--danger);  font-weight: 600; }
    .chart-tooltip .tip-warn { color: var(--warning); font-weight: 600; }

    /* ── Hyperparam form ── */
    .hp-form {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 0.5rem;
    }

    .hp-group {
      display: flex;
      flex-direction: column;
      gap: 0.2rem;
    }

    .hp-group label {
      font-size: 0.7rem;
      color: var(--muted);
      font-weight: 500;
    }

    .hp-group input {
      background: var(--bg);
      border: 1px solid var(--border);
      border-radius: 5px;
      color: var(--text);
      padding: 0.3rem 0.5rem;
      font-size: 0.78rem;
      width: 100%;
      outline: none;
      transition: border-color 0.15s;
    }
    .hp-group input:focus { border-color: var(--accent); }
    .hp-group input:disabled { opacity: 0.4; }

    .hp-full { grid-column: 1 / -1; }

    /* ── Collapsible Sections ── */
    .collapsible-section {
      background: var(--panel);
      border: 1px solid var(--border);
      border-radius: 10px;
      transition: all 0.2s ease;
    }

    .collapsible-section summary {
      padding: 0.6rem 0.9rem;
      font-weight: 600;
      font-size: 0.8rem;
      text-transform: uppercase;
      letter-spacing: 0.05em;
      color: var(--muted);
      cursor: pointer;
      list-style: none;
      display: flex;
      align-items: center;
      gap: 0.6rem;
      border-bottom: 1px solid var(--border);
      user-select: none;
      transition: background 0.15s;
      border-radius: 10px 10px 0 0;
    }

    .collapsible-section summary:hover {
      background: var(--panel2);
    }

    .collapsible-section:not([open]) summary {
      border-bottom: none;
      border-radius: 10px;
    }

    .section-title {
      flex: 1;
    }

    .section-toggle {
      transition: transform 0.2s ease;
      font-size: 1.2rem;
      color: var(--accent2);
      flex-shrink: 0;
      width: 1.4rem;
      text-align: center;
      line-height: 1;
    }

    .collapsible-section[open] .section-toggle {
      transform: rotate(180deg);
    }

    .section-content {
      padding: 0;
      max-height: 400px;
      overflow-y: auto;
      overflow-x: auto;
      border-radius: 0 0 10px 10px;
    }

    .section-content--viz {
      max-height: none;
      overflow: hidden;
    }

    .section-content--runs {
      max-height: none;
      flex: 1;
      min-height: 0;
    }

    .section-content::-webkit-scrollbar {
      width: 6px;
    }

    .section-content::-webkit-scrollbar-track {
      background: var(--bg);
      border-radius: 3px;
    }

    .section-content::-webkit-scrollbar-thumb {
      background: var(--border);
      border-radius: 3px;
    }

    .section-content::-webkit-scrollbar-thumb:hover {
      background: var(--muted);
    }

    .charts-grid,
    .hp-form {
      padding: 0.75rem;
    }

    .gen-table-wrap,
    .eval-table-wrap {
      overflow-x: auto;
      padding: 0.75rem;
    }

    .checkpoint-list {
      display: flex;
      flex-direction: column;
      gap: 0.5rem;
      padding: 0.75rem;
    }

    .checkpoint-item {
      background: var(--bg);
      border: 1px solid var(--border);
      border-radius: 6px;
      padding: 0.6rem 0.75rem;
      display: flex;
      align-items: center;
      justify-content: space-between;
      gap: 0.75rem;
      transition: border-color 0.15s;
    }

    .checkpoint-item:hover {
      border-color: var(--accent);
    }

    .checkpoint-info {
      flex: 1;
      min-width: 0;
    }

    .checkpoint-name {
      font-size: 0.8rem;
      font-weight: 600;
      color: var(--text);
      margin-bottom: 0.2rem;
    }

    .checkpoint-meta {
      font-size: 0.7rem;
      color: var(--muted);
      display: flex;
      gap: 0.75rem;
      flex-wrap: wrap;
    }

    .checkpoint-actions {
      display: flex;
      gap: 0.25rem;
    }

    table {
      width: 100%;
      border-collapse: collapse;
      font-size: 0.78rem;
    }

    thead th {
      padding: 0.4rem 0.75rem;
      text-align: right;
      color: var(--muted);
      font-weight: 600;
      font-size: 0.7rem;
      text-transform: uppercase;
      letter-spacing: 0.04em;
      border-bottom: 1px solid var(--border);
      white-space: nowrap;
    }
    thead th:first-child { text-align: left; }

    tbody td {
      padding: 0.35rem 0.75rem;
      text-align: right;
      border-bottom: 1px solid var(--border);
      color: var(--text);
    }
    tbody td:first-child { text-align: left; font-weight: 600; }
    tbody tr:last-child td { border-bottom: none; }
    tbody tr:hover { background: var(--panel2); }

    .sr-low  { color: var(--danger); }
    .sr-mid  { color: var(--warning); }
    .sr-high { color: var(--success); }

    /* ── Modal ── */
    .modal-backdrop {
      position: fixed;
      inset: 0;
      background: rgba(0,0,0,0.7);
      z-index: 200;
      display: flex;
      align-items: center;
      justify-content: center;
      backdrop-filter: blur(3px);
    }
    .modal-backdrop.hidden { display: none; }

    .modal-box {
      background: var(--panel);
      border: 1px solid var(--border);
      border-radius: 12px;
      padding: 1.5rem;
      width: 100%;
      max-width: 460px;
      max-height: 90vh;
      overflow-y: auto;
    }

    .modal-title {
      font-size: 1rem;
      font-weight: 700;
      margin-bottom: 1rem;
    }

    .modal-footer {
      display: flex;
      justify-content: flex-end;
      gap: 0.5rem;
      margin-top: 1.25rem;
    }

    /* ── Toast ── */
    #toastBox {
      position: fixed;
      bottom: 1.5rem;
      right: 1.5rem;
      z-index: 300;
      display: flex;
      flex-direction: column;
      gap: 0.5rem;
      pointer-events: none;
    }

    .toast {
      background: var(--panel2);
      border: 1px solid var(--border);
      border-radius: 8px;
      padding: 0.65rem 1rem;
      font-size: 0.8rem;
      min-width: 220px;
      max-width: 340px;
      opacity: 0;
      transform: translateX(20px);
      transition: opacity 0.25s, transform 0.25s;
      pointer-events: all;
    }
    .toast.show { opacity: 1; transform: translateX(0); }
    .toast.t-ok  { border-color: var(--success); color: var(--success); }
    .toast.t-err { border-color: var(--danger);  color: var(--danger);  }
    .toast.t-info { border-color: var(--accent2); color: var(--accent2); }

    /* ── Loading overlay ── */
    #loadingOverlay {
      position: fixed;
      inset: 0;
      background: var(--bg);
      z-index: 500;
      display: flex;
      align-items: center;
      justify-content: center;
      flex-direction: column;
      gap: 1rem;
      transition: opacity 0.4s;
    }
    #loadingOverlay.gone { opacity: 0; pointer-events: none; }

    .spinner {
      width: 40px;
      height: 40px;
      border: 3px solid var(--border);
      border-top-color: var(--accent);
      border-radius: 50%;
      animation: spin 0.8s linear infinite;
    }
    @keyframes spin { to { transform: rotate(360deg); } }

    /* ── Responsive ── */
    @media (max-width: 900px) {
      .app-body {
        grid-template-columns: 1fr;
        grid-template-rows: auto auto auto;
      }
      .left-col        { grid-column: 1; grid-row: 1; }
      .right-col       { grid-column: 1; grid-row: 2; }
      .controls-bar-row { grid-column: 1; grid-row: 3; }
      .canvas-wrap     { height: 50vw; }
      #section-runs    { min-height: 150px; flex: 0 0 auto; }
      .charts-grid     { grid-template-columns: repeat(2, 1fr); }
      html, body       { overflow: auto; height: auto; }
    }

    @media (max-width: 768px) {
      /*
       * On mobile, promote .left-col's children directly into the app-body
       * grid so we can slot .ctrl-btns (pulled out of .controls-bar) between
       * .canvas-wrap and #epStatsPanel without touching the DOM.
       *
       * Strategy:
       *  1. display:contents on .left-col makes its children direct grid
       *     participants, each assigned an explicit grid-row.
       *  2. .controls-bar becomes display:contents too, making .ctrl-btns a
       *     direct grid participant that can be placed at grid-row 3 (between
       *     canvas and epStatsPanel).
       *  3. .ctrl-sliders and .ctrl-stats are hidden on mobile for a cleaner UI.
       *  4. .right-col is pushed down below all left-col content.
       */
      .app-body {
        grid-template-columns: 1fr;
        grid-template-rows: auto auto auto auto auto auto;
      }

      /* Flatten .left-col into the grid */
      .left-col {
        display: contents;
      }

      /* Flatten .controls-bar into the grid so .ctrl-btns can be a grid item */
      .controls-bar {
        display: contents;
      }

      /* Assign explicit rows to each logical section */
      #section-visualization { grid-column: 1; grid-row: 1; }
      .canvas-wrap      { height: 50vw; }
      .ctrl-btns        { grid-column: 1; grid-row: 2; padding: 0.5rem; background: var(--panel); border: 1px solid var(--border); border-radius: 10px; display: flex; gap: 0.4rem; flex-wrap: wrap; }
      .ctrl-sliders     { grid-column: 1; grid-row: 3; display: flex; padding: 0.5rem 0.75rem; }
      #section-episode-stats { grid-column: 1; grid-row: 4; }
      #section-runs     { grid-column: 1; grid-row: 5; min-height: 150px; flex: 0 0 auto; }
      .right-col        { grid-column: 1; grid-row: 6; }

      /* Hide live stats on mobile — already visible in the canvas HUD */
      .ctrl-stats { display: none; }
    }

    @media (max-width: 640px) {
      header { flex-wrap: wrap; gap: 0.5rem; }
      .charts-grid { grid-template-columns: 1fr; }
      .hp-form { grid-template-columns: 1fr; }
    }

    /* ── Misc ── */
    details > summary { user-select: none; }

    .spacer { flex: 1; }

    a { color: var(--accent2); text-decoration: none; }
    a:hover { text-decoration: underline; }

    .kbd {
      display: inline-block;
      background: var(--border);
      border-radius: 3px;
      padding: 0 4px;
      font-size: 0.7rem;
      color: var(--muted);
      font-family: monospace;
    }

    input[type=text], input[type=number], textarea, select {
      background: var(--bg);
      border: 1px solid var(--border);
      border-radius: 5px;
      color: var(--text);
      padding: 0.35rem 0.6rem;
      font-size: 0.82rem;
      outline: none;
      font-family: inherit;
      transition: border-color 0.15s;
    }
    input:focus, textarea:focus, select:focus { border-color: var(--accent); }

    .form-row {
      display: flex;
      flex-direction: column;
      gap: 0.25rem;
      margin-bottom: 0.75rem;
    }
    .form-row label { font-size: 0.78rem; color: var(--muted); font-weight: 500; }
    .form-row input, .form-row textarea { width: 100%; }