@import url('https://fonts.googleapis.com/css2?family=Bebas+Neue&family=DM+Mono:ital,wght@0,300;0,400;0,500;1,300&family=DM+Sans:ital,opsz,wght@0,9..40,300;0,9..40,400;0,9..40,500;0,9..40,600;1,9..40,300&display=swap');

      /* ================= CSS VARIABLES ================= */
      :root {
        --bg-base:      #0d0e10;
        --bg-surface:   #13151a;
        --bg-raised:    #1a1d24;
        --bg-overlay:   #21252e;

        --border:       #2a2e38;
        --border-focus: #3d4455;

        --text-primary:   #e8eaf0;
        --text-secondary: #8a8fa0;
        --text-muted:     #4a4f60;

        --accent:         #7fff00;
        --accent-dim:     #4db300;
        --accent-glow:    rgba(127, 255, 0, 0.15);
        --accent-subtle:  rgba(127, 255, 0, 0.07);

        --danger:   #ff4040;
        --warning:  #ffb340;
        --info:     #40a8ff;

        --radius-sm:  4px;
        --radius-md:  8px;
        --radius-lg:  14px;

        --font-display: 'Bebas Neue', sans-serif;
        --font-mono:    'DM Mono', monospace;
        --font-body:    'DM Sans', sans-serif;

        --nav-height:   52px;
        --transition:   0.18s ease;
      }

      /* ================= RESET & BASE ================= */
      *, *::before, *::after {
        box-sizing: border-box;
        margin: 0;
        padding: 0;
      }

      ::-webkit-scrollbar { width: 5px; height: 5px; }
      ::-webkit-scrollbar-track { background: var(--bg-base); }
      ::-webkit-scrollbar-thumb { background: var(--border); border-radius: 99px; }
      ::-webkit-scrollbar-thumb:hover { background: var(--border-focus); }
      * { scrollbar-width: thin; scrollbar-color: var(--border) var(--bg-base); }

      html {
        font-size: 16px;
        -webkit-font-smoothing: antialiased;
        -moz-osx-font-smoothing: grayscale;
      }

      html, body {
        width: 100%;
        height: 100%;
        overflow: hidden;
        background-color: var(--bg-base);
        color: var(--text-primary);
        font-family: var(--font-body);
        font-weight: 400;
      }

      /* subtle dot-grid texture */
      body::before {
        content: '';
        position: fixed;
        inset: 0;
        background-image: radial-gradient(circle, var(--text-muted) 1px, transparent 1px);
        background-size: 28px 28px;
        opacity: 0.04;
        pointer-events: none;
        z-index: 0;
      }

      .mono { font-family: var(--font-mono); }
      .display { font-family: var(--font-display); letter-spacing: 0.04em; }

      .enclosing-size {
        margin-top: 12px;
        padding: 8px 10px;
        background: var(--bg-base);
        border: 1px solid var(--border);
        border-radius: var(--radius-sm);
        color: var(--accent);
        font-family: var(--font-mono);
        font-size: 13px;
        font-weight: 500;
        text-align: center;
        letter-spacing: 0.5px;
      }

      /* ================= BURGER MENU (legacy, unused but kept) ================= */
      .burger-menu-btn {
        position: fixed;
        top: 15px;
        right: 15px;
        z-index: 999;
        background: var(--bg-raised);
        border: 1px solid var(--border);
        border-radius: var(--radius-sm);
        width: 45px;
        height: 45px;
        cursor: pointer;
        display: flex;
        flex-direction: column;
        justify-content: center;
        align-items: center;
        gap: 6px;
        transition: all var(--transition);
        padding: 0;
      }
      .burger-menu-btn:hover {
        border-color: var(--accent);
        box-shadow: 0 0 12px var(--accent-glow);
      }
      .burger-menu-btn.open {
        background: var(--accent);
      }
      .burger-menu-btn.open svg path {
        stroke: var(--bg-base);
      }
      .burger-line {
        width: 24px;
        height: 2px;
        background: var(--accent);
        transition: all var(--transition);
        border-radius: 2px;
      }
      .burger-menu-btn.open .burger-line:nth-child(1) {
        transform: rotate(45deg) translateY(11px);
      }
      .burger-menu-btn.open .burger-line:nth-child(2) {
        opacity: 0;
      }
      .burger-menu-btn.open .burger-line:nth-child(3) {
        transform: rotate(-45deg) translateY(-11px);
      }

      /* ================= CONTROLS PANEL ================= */
      .controls-panel {
        position: fixed;
        top: 0;
        left: 0;
        width: 300px;
        height: 100%;
        background: var(--bg-surface);
        border-right: 1px solid var(--border);
        z-index: 998;
        padding: 24px 20px;
        box-sizing: border-box;
        overflow-y: auto;
        box-shadow: 2px 0 20px rgba(0, 0, 0, 0.4);
        transform: translateX(0);
        transition: transform var(--transition);
      }
      .controls-panel h1 {
        font-family: var(--font-display);
        color: var(--text-primary);
        font-size: 24px;
        letter-spacing: 0.04em;
        margin-top: 4px;
        margin-bottom: 22px;
        padding-bottom: 14px;
        border-bottom: 1px solid var(--border);
        display: flex;
        align-items: center;
        gap: 8px;
      }
      .controls-panel h1 img {
        width: 22px;
        height: 22px;
        border-radius: var(--radius-sm);
      }

      /* ================= FILE INPUT SECTION ================= */
      .file-input-section {
        margin-bottom: 25px;
      }
      .file-input-label {
        display: block;
        color: var(--text-secondary);
        font-family: var(--font-mono);
        font-weight: 500;
        font-size: 11px;
        margin-bottom: 8px;
        text-transform: uppercase;
        letter-spacing: 0.08em;
      }
      #file-input {
        display: block;
        width: 100%;
        padding: 10px;
        margin-bottom: 10px;
        background: var(--bg-base);
        color: var(--accent);
        border: 1px solid var(--border);
        border-radius: var(--radius-sm);
        font-family: var(--font-mono);
        font-size: 12px;
        cursor: pointer;
        transition: border-color var(--transition);
      }
      #file-input:hover {
        border-color: var(--accent);
      }

      /* ================= BUTTONS ================= */
      .button-group {
        display: flex;
        flex-direction: column;
        gap: 10px;
      }
      button {
        padding: 12px 16px;
        background: var(--bg-raised);
        color: var(--text-primary);
        border: 1px solid var(--border);
        border-radius: var(--radius-md);
        font-family: var(--font-mono);
        font-weight: 500;
        font-size: 12px;
        cursor: pointer;
        text-transform: uppercase;
        letter-spacing: 0.06em;
        transition: all var(--transition);
      }
      button:hover {
        background: var(--accent-subtle);
        border-color: var(--accent);
        color: var(--accent);
        box-shadow: 0 0 12px var(--accent-glow);
      }
      button:active {
        transform: scale(0.98);
      }
      #clear-button {
        background: var(--bg-raised);
        border-color: var(--border);
        color: var(--danger);
      }
      #clear-button:hover {
        background: rgba(255, 64, 64, 0.08);
        border-color: var(--danger);
        color: var(--danger);
        box-shadow: 0 0 12px rgba(255, 64, 64, 0.18);
      }

      /* ================= LAYOUT ================= */
      .main-content {
        display: flex;
        width: 100%;
        height: 100vh;
        align-items: center;
        overflow: hidden;
        transition: margin-left var(--transition);
        position: relative;
        z-index: 1;
      }
      .main-content.menu-open {
        margin-left: 300px;
      }
      .canvas-container {
        flex: 1;
        width: 100%;
        height: 100%;
        overflow: hidden;
        position: relative;
      }

      /* ================= WATERMARK ================= */
      .canvas-watermark {
        position: absolute;
        top: 18px;
        left: 24px;
        z-index: 5;
        display: flex;
        align-items: center;
        gap: 10px;
        pointer-events: none;
        opacity: 0.55;
        user-select: none;
      }
      .canvas-watermark img {
        width: 26px;
        height: 26px;
        border-radius: var(--radius-sm);
        filter: drop-shadow(0 0 6px var(--accent-glow));
      }
      .canvas-watermark span {
        font-family: var(--font-display);
        font-size: 22px;
        letter-spacing: 0.06em;
        color: var(--text-primary);
        text-shadow: 0 0 12px rgba(0, 0, 0, 0.6);
      }
      .canvas-watermark span .accent {
        color: var(--accent);
      }

      /* ================= DOUBLE SLIDER ================= */
      .double-slider-container {
        display: none;
        flex-direction: column;
        align-items: center;
        width: 60px;
        height: 100%;
        background: var(--bg-surface);
        border: 1px solid var(--border);
        border-radius: var(--radius-lg);
        margin-right: 15px;
        box-shadow: inset 0 0 10px rgba(0,0,0,0.4);
        padding: 12px 0;
        box-sizing: border-box;
      }
      .double-slider-container.active {
        display: flex;
      }
      .slider-value-input {
        width: 44px;
        background: var(--bg-base);
        color: var(--accent);
        border: 1px solid var(--border);
        border-radius: var(--radius-sm);
        font-family: var(--font-mono);
        font-size: 12px;
        font-weight: 500;
        text-align: center;
        padding: 4px 2px;
        box-sizing: border-box;
        cursor: text;
      }
      .slider-value-input:focus {
        outline: none;
        border-color: var(--accent);
        box-shadow: 0 0 4px var(--accent-glow);
      }
      .slider-track {
        position: relative;
        width: 28px;
        flex: 1;
        margin: 10px 0;
        display: flex;
        align-items: center;
        justify-content: center;
      }
      .slider-track-line {
        position: absolute;
        top: 0; bottom: 0;
        left: 50%;
        transform: translateX(-50%);
        width: 6px;
        background: var(--border);
        border-radius: 3px;
        pointer-events: none;
      }
      .slider-range {
        position: absolute;
        left: 50%;
        transform: translateX(-50%);
        width: 6px;
        background: var(--accent);
        border-radius: 3px;
        box-shadow: 0 0 8px var(--accent-glow);
        pointer-events: none;
      }
      .slider-thumb {
        position: absolute;
        left: 50%;
        width: 20px;
        height: 20px;
        background: var(--text-primary);
        border: 2px solid var(--accent);
        border-radius: 50%;
        transform: translate(-50%, -50%);
        cursor: ns-resize;
        z-index: 2;
        transition: box-shadow 0.1s, top 0.1s ease-out;
        box-sizing: border-box;
      }
      .slider-thumb:hover,
      .slider-thumb:active {
        box-shadow: 0 0 0 4px var(--accent-glow);
      }
      .slider-thumb.thumb-offset-max {
        background: var(--bg-overlay);
        border-color: var(--accent);
        opacity: 0.9;
      }
      .slider-thumb.thumb-offset-min {
        background: var(--bg-raised);
        border-color: var(--accent);
        opacity: 0.9;
      }

      /* ================= RESPONSIVE ================= */
      @media (max-width: 768px) {
        .controls-panel {
          width: 100%;
        }
        .main-content.menu-open {
          margin-left: 0;
        }
      }

      /* ================= STACK SIZE CONTROLS ================= */
      #stack-controls {
        display: flex;
        flex-direction: column;
        gap: 8px;
        margin-top: 18px;
        font-family: var(--font-mono);
      }
      #stack-controls label {
        color: var(--text-secondary);
        font-weight: 500;
        font-size: 11px;
        text-transform: uppercase;
        letter-spacing: 0.08em;
      }
      #stack-count, #cluster-gap {
        width: 60px;
        padding: 6px 8px;
        background: var(--bg-base);
        color: var(--accent);
        border: 1px solid var(--border);
        border-radius: var(--radius-sm);
        font-family: var(--font-mono);
        font-size: 13px;
        font-weight: 500;
        text-align: center;
        cursor: text;
        transition: border-color 0.2s, box-shadow 0.2s;
      }
      #stack-count:focus, #cluster-gap:focus {
        outline: none;
        border-color: var(--accent);
        box-shadow: 0 0 6px var(--accent-glow);
      }
      #enclosing-size-display {
        display: flex;
        align-items: center;
        justify-content: center;
        gap: 4px;
        flex-wrap: wrap;
      }
      .size-axis-input {
        width: 52px;
        padding: 2px 4px;
        background: transparent;
        border: none;
        color: var(--accent);
        font-family: var(--font-mono);
        font-size: 13px;
        font-weight: 500;
        text-align: center;
      }
      .size-axis-input:disabled {
        opacity: 0.5;
        cursor: default;
      }
      .size-axis-editable {
        background: var(--bg-base);
        border: 1px solid var(--border-focus);
        border-radius: var(--radius-sm);
        cursor: text;
        transition: border-color 0.2s, box-shadow 0.2s;
      }
      .size-axis-editable:focus {
        outline: none;
        border-color: var(--accent);
        box-shadow: 0 0 6px var(--accent-glow);
      }

      /* ================= DRAG & DROP ================= */
      #file-drop-area {
        display: flex;
        align-items: center;
        justify-content: center;
        height: 64px;
        border: 1.5px dashed var(--border-focus);
        border-radius: var(--radius-md);
        background: var(--bg-base);
        color: var(--text-secondary);
        font-size: 12px;
        font-weight: 500;
        font-family: var(--font-mono);
        text-align: center;
        cursor: pointer;
        transition: background 0.2s, border-color 0.2s, color 0.2s;
        user-select: none;
        padding: 0 12px;
      }
      #file-drop-area.hover {
        background: var(--accent-subtle);
        border-color: var(--accent);
        color: var(--accent);
      }
      #file-drop-area input[type="file"] {
        display: none;
      }

      .panel-toggle {
        position: fixed;
        top: 20px;
        left: 300px;
        z-index: 999;
        width: 26px;
        height: 48px;
        background: var(--bg-raised);
        color: var(--text-secondary);
        border: 1px solid var(--border);
        border-left: none;
        border-radius: 0 var(--radius-md) var(--radius-md) 0;
        cursor: pointer;
        font-size: 16px;
        transition: all var(--transition);
      }
      .panel-toggle:hover {
        color: var(--accent);
        border-color: var(--accent);
      }

      /* Closed state */
      .controls-panel.closed {
        transform: translateX(-100%);
      }
      .main-content.panel-closed {
        margin-left: 0;
      }
      .panel-toggle.closed {
        left: 0;
        border-left: 1px solid var(--border);
      }

      #gap-controls {
        display: flex;
        align-items: center;
        gap: 6px;
        margin-top: 6px;
      }
      #gap-controls span {
        font-size: 11px;
        color: var(--text-muted);
        font-family: var(--font-mono);
      }
      .grid-controls {
        color: var(--text-secondary);
        font-family: var(--font-mono);
        font-size: 13px;
      }
      .grid-controls input[type="checkbox"] {
        accent-color: var(--accent);
      }

      /* ================= VERSION CONTROLS ================= */
      #version-controls {
        display: flex;
        align-items: center;
        gap: 8px;
        margin-top: 16px;
        font-family: var(--font-mono);
      }
      #version-controls label {
        color: var(--text-secondary);
        font-weight: 500;
        font-size: 11px;
        text-transform: uppercase;
        letter-spacing: 0.08em;
      }
      #version-override {
        width: 60px;
        padding: 6px 8px;
        background: var(--bg-base);
        color: var(--accent);
        border: 1px solid var(--border);
        border-radius: var(--radius-sm);
        font-family: var(--font-mono);
        font-size: 13px;
        font-weight: 500;
        text-align: center;
        cursor: text;
        transition: border-color 0.2s, box-shadow 0.2s;
      }
      #version-override:focus {
        outline: none;
        border-color: var(--accent);
        box-shadow: 0 0 6px var(--accent-glow);
      }
    
/* ── Selection HUD ─────────────────────────────────────────────────────────
   Shows the currently selected region's name and the active keyboard
   controls (move / clone / delete). Appears on click, hides on deselect. */

.selection-hud {
  position: absolute;
  bottom: 16px;
  left: 16px;
  padding: 8px 14px;
  background: rgba(20, 20, 26, 0.5);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  border: 1px solid rgba(255, 255, 255, 0.15);
  border-radius: 8px;
  color: #f0f0f0;
  font-size: 12px;
  box-shadow: 0 4px 14px rgba(0, 0, 0, 0.3);
  z-index: 20;
  transition: opacity 0.12s ease, transform 0.12s ease;
}

.selection-hud.hidden {
  opacity: 0;
  transform: translateY(6px);
  pointer-events: none;
}

.selection-hud-name {
  font-weight: 600;
  margin-bottom: 3px;
  word-break: break-word;
}

.selection-hud-keys {
  color: var(--text-secondary, #bbb);
  font-size: 11px;
  white-space: nowrap;
}

.hud-key {
  display: inline-block;
  padding: 1px 5px;
  margin: 0 1px;
  background: rgba(255, 255, 255, 0.12);
  border: 1px solid rgba(255, 255, 255, 0.22);
  border-radius: 4px;
  font-size: 10px;
  font-weight: 600;
  color: #fff;
}

.hud-sep {
  margin: 0 5px;
  color: rgba(255, 255, 255, 0.3);
}

/* ── Clone GUI overlay ─────────────────────────────────────────────────────
   Appears on top of the canvas when a region is selected and "C" is
   pressed. Needs .canvas-container to be position:relative (added below)
   so it anchors to the canvas rather than the page. */

.canvas-container {
  position: relative; /* anchors .selection-hud / .clone-gui inside the canvas area */
}

.clone-gui {
  position: absolute;
  top: 16px;
  right: 16px;
  min-width: 190px;
  padding: 14px 16px;
  background: rgba(20, 20, 26, 0.55);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  border: 1px solid rgba(255, 255, 255, 0.15);
  border-radius: 10px;
  color: #f0f0f0;
  font-size: 13px;
  box-shadow: 0 6px 20px rgba(0, 0, 0, 0.35);
  z-index: 20;
  transition: opacity 0.12s ease, transform 0.12s ease;
}

.clone-gui.hidden {
  opacity: 0;
  transform: translateY(-6px);
  pointer-events: none;
}

.clone-gui-header {
  font-weight: 600;
  font-size: 14px;
  margin-bottom: 6px;
}

.clone-gui-target {
  font-size: 11px;
  color: var(--text-secondary, #aaa);
  margin-bottom: 10px;
  word-break: break-word;
}

.clone-gui-row {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 6px;
}

.clone-gui-row label {
  width: 14px;
  font-weight: 600;
  color: var(--text-secondary, #ccc);
}

.clone-gui-row input {
  flex: 1;
  width: 100%;
  background: rgba(255, 255, 255, 0.08);
  border: 1px solid rgba(255, 255, 255, 0.2);
  border-radius: 4px;
  color: #fff;
  padding: 3px 6px;
  font-size: 12px;
}

.clone-gui-row input:focus {
  outline: none;
  border-color: rgba(255, 255, 255, 0.45);
}

.clone-gui-actions {
  display: flex;
  gap: 6px;
  margin-top: 10px;
}

.clone-gui-actions button {
  flex: 1;
  cursor: pointer;
  border-radius: 6px;
  border: 1px solid rgba(255, 255, 255, 0.2);
  background: rgba(255, 255, 255, 0.08);
  color: #fff;
  padding: 5px 0;
  font-size: 12px;
}

.clone-gui-actions button:hover {
  background: rgba(255, 255, 255, 0.18);
}

.clone-gui-hint {
  margin-top: 8px;
  font-size: 10px;
  color: var(--text-secondary, #888);
  text-align: center;
}