@import url('https://fonts.googleapis.com/css2?family=Poppins:wght@400;500;600;700&display=swap');

  :root {
    --bg-deep: #05080A;
    --bg-panel: #080B10;
    --bg-card: #0B0E14;
    --border: #1F2937;
    --cyan: #00FFFF;
    --green: #00FF00;
    --amber: #FFBF00;
    --red: #FF3333;
    --text: #E0E0E0;
    --muted: #8892B0;
    --layer1: #1A2B4C;
    --layer2: #2A2A2A;
    --layer3: #3A3E45;
    --layer4: #4A3B22;
    --layer5: #2F4F4F;
  }

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

  body {
    background: var(--bg-deep);
    color: var(--text);
    font-family: 'Poppins', sans-serif;
    font-size: 16px;
    font-weight: normal;
    font-style: normal;
    min-height: 100vh;
    overflow-x: hidden;
  }

  /* Scanline overlay */
  body::before {
    content: '';
    position: fixed;
    top: 0; left: 0; right: 0; bottom: 0;
    background: repeating-linear-gradient(0deg, transparent, transparent 2px, rgba(0,255,255,0.01) 2px, rgba(0,255,255,0.01) 4px);
    pointer-events: none;
    z-index: 9999;
  }

  .title-bar {
    background: var(--bg-panel);
    border-bottom: 1px solid var(--border);
    padding: 7px 16px;
    text-align: center;
    color: var(--cyan);
    font-size: 16px;
    font-weight: normal;
    letter-spacing: normal;
    text-transform: none;
  }

  .main-grid {
    display: grid;
    grid-template-columns: 383px 1fr 410px;
    grid-template-rows: 1fr 72px;
    height: calc(100vh - 34px);
    gap: 0;
    overflow: hidden;
  }

  /* ===== PANEL 1: CONTROLS ===== */
  .panel-controls {
    background: var(--bg-panel);
    border-right: 1px solid var(--border);
    overflow-y: auto;
    padding: 8px;
    display: flex;
    flex-direction: column;
    gap: 8px;
    grid-row: 1 / 2;
  }

  /* ===== PANEL 2: PLOTS ===== */
  .panel-plots {
    background: var(--bg-deep);
    overflow: hidden;
    padding: 6px;
    display: flex;
    flex-direction: column;
    gap: 6px;
    grid-row: 1 / 2;
  }

  /* ===== PANEL 3: ENVIRONMENT ===== */
  .panel-env {
    background: var(--bg-panel);
    border-left: 1px solid var(--border);
    padding: 6px 4px 4px 4px;
    overflow: hidden;
    grid-row: 1 / 2;
    display: flex;
    flex-direction: column;
  }

  /* ===== PANEL 4: ANALYTICS (bottom) ===== */
  .panel-analytics {
    grid-column: 1 / 4;
    grid-row: 2 / 3;
    background: var(--bg-panel);
    border-top: 1px solid var(--border);
    display: flex;
    align-items: stretch;
    padding: 6px;
    gap: 6px;
    min-height: 70px;
    max-height: 80px;
  }

  /* ===== GROUPBOX ===== */
  .group-box {
    border: 1px solid var(--border);
    border-radius: 4px;
    background: var(--bg-card);
    position: relative;
    padding: 10px 8px 8px 8px;
  }

  .group-box-title {
    position: absolute;
    top: -9px;
    left: 10px;
    background: var(--bg-card);
    color: var(--green);
    font-size: 14px;
    font-weight: normal;
  }

  /* ===== FORM ROWS ===== */
  .form-row {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 5px;
    gap: 4px;
  }

  .form-row label {
    color: var(--muted);
    font-size: 14px;
    font-weight: normal;
    white-space: nowrap;
    flex-shrink: 0;
    min-width: 100px;
  }

  input[type="text"], input[type="number"], select {
    background: var(--bg-deep);
    color: var(--text);
    border: 1px solid var(--border);
    border-radius: 3px;
    padding: 4px 6px;
    font-family: 'Poppins', sans-serif;
    font-size: 14px;
    font-weight: normal;
  }

  input[type="text"]:focus, input[type="number"]:focus, select:focus {
    border-color: var(--cyan);
    background: var(--bg-card);
  }

  select option { background: var(--bg-deep); }

  /* ===== BUTTONS ===== */
  .btn {
    background: #1A2B4C;
    color: var(--cyan);
    border: 1px solid var(--cyan);
    border-radius: 4px;
    padding: 6px 10px;
    font-family: 'Poppins', sans-serif;
    font-size: 14px;
    cursor: pointer;
    font-weight: normal;
    text-transform: none;
    transition: all 0.15s;
    letter-spacing: normal;
  }

  .btn:hover { background: var(--cyan); color: var(--bg-deep); }
  .btn:active { transform: scale(0.97); }

  .btn-primary {
    background: #004400;
    color: var(--green);
    border-color: var(--green);
    padding: 10px;
    width: 100%;
    font-size: 16px;
    font-weight: normal;
    letter-spacing: normal;
  }
  .btn-primary:hover { background: var(--green); color: #000; }

  .btn-warning {
    background: #442200;
    color: var(--amber);
    border-color: var(--amber);
    width: 100%;
    padding: 8px;
    font-weight: normal;
    letter-spacing: normal;
  }
  .btn-warning:hover { background: var(--amber); color: #000; }

  .btn-sm {
    font-size: 13px;
    padding: 2px 6px;
    font-weight: normal;
    letter-spacing: normal;
  }

  /* ===== LAYER CARDS ===== */
  .layer-card {
    background: var(--bg-deep);
    border: 1px solid var(--border);
    border-left: 3px solid var(--cyan);
    border-radius: 2px;
    padding: 6px;
    margin-bottom: 6px;
  }

  .layer-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 5px;
  }

  .layer-title {
    color: var(--green);
    font-size: 14px;
    font-weight: normal;
  }

  .layer-btns { display: flex; gap: 3px; }

  /* ===== CHART CONTAINERS ===== */
  .chart-box {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 4px;
    padding: 6px 8px;
    position: relative;
    display: flex;
    flex-direction: column;
    overflow: hidden;
    min-height: 0;
  }

  .chart-box-ascan { flex: 2; }
  .chart-box-bscan { flex: 4; }
  .chart-box-cscan { flex: 3; }

  .chart-box-title {
    color: var(--cyan);
    font-size: 14px;
    font-weight: normal;
    margin-bottom: 4px;
    text-align: center;
    letter-spacing: normal;
    flex-shrink: 0;
  }

  .chart-box canvas { display: block; flex: 1; min-height: 0; }

  /* ===== ENV CANVAS ===== */
  .env-title {
    color: var(--cyan);
    font-size: 14px;
    font-weight: normal;
    text-align: center;
    margin-bottom: 4px;
    letter-spacing: normal;
    flex-shrink: 0;
  }

  #env-canvas {
    display: block;
    width: 100%;
    flex: 1;
    min-height: 0;
    background: #080C14;
    border: 1px solid var(--border);
    border-radius: 2px;
  }

  /* ===== METRIC CARDS ===== */
  .metric-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 6px;
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 4px;
    gap: 2px;
  }

  .metric-title {
    color: var(--muted);
    font-size: 12px;
    font-weight: normal;
    letter-spacing: normal;
    text-transform: none;
    text-align: center;
  }

  .metric-value {
    color: var(--cyan);
    font-size: 16px;
    font-weight: normal;
    font-family: 'Poppins', sans-serif;
  }

  /* Scrollbar */
  ::-webkit-scrollbar { width: 8px; }
  ::-webkit-scrollbar-track { background: var(--bg-deep); }
  ::-webkit-scrollbar-thumb { background: var(--border); border-radius: 4px; }
  ::-webkit-scrollbar-thumb:hover { background: var(--cyan); }

  /* Preset row */
  .preset-row {
    display: flex;
    align-items: center;
    gap: 6px;
    margin-bottom: 8px;
  }

  .preset-row label { color: var(--muted); font-size: 14px; font-weight: normal; white-space: nowrap; }
  .preset-row select { flex: 1; }

  /* Action buttons */
  .action-section {
    display: flex;
    flex-direction: column;
    gap: 8px;
    margin-top: 4px;
  }

  /* B-scan and C-scan canvas fill their flex containers */
  #bscan-canvas, #cscan-canvas {
    display: block;
    width: 100%;
    flex: 1;
    min-height: 0;
  }

  /* Responsive tweaks */
  @media (max-width: 1000px) {
    .main-grid { grid-template-columns: 240px 1fr; }
    .panel-env { display: none; }
    .panel-analytics { grid-column: 1/3; }
  }