Rack Panel

Physical Analog

Reference devices: 19-inch rack-mount audio equipment front panels (Mackie, PreSonus, Behringer), modular synthesizer panels. Mechanism: Derived from the 19-inch equipment rack standard (EIA-310). Audio, broadcast, and server equipment is mounted in standardized racks where each device occupies 1-4 "rack units" (1U = 1.75 inches / 44.45mm). The front panel of each device has controls and indicators arranged in a vertical strip. When multiple devices are stacked, they form a vertical sidebar of labeled modules.

Geometry

CSS Recipe

Container (.rack-panel)

.rack-panel {
  width: 200px; background: var(--bg-raised);
  border: 1px solid var(--border-subtle); border-radius: var(--radius-lg);
  box-shadow: var(--shadow-deep); overflow: hidden;
}

Slot (.rack-slot)

.rack-slot {
  padding: 10px 14px; border-bottom: 1px solid var(--border-subtle);
  cursor: pointer; transition: background 0.12s;
  display: flex; align-items: center; gap: 8px;
}
.rack-slot:last-child { border-bottom: none; }

Hover

.rack-slot:hover { background: var(--glow-color); }

Active

.rack-slot.active { background: var(--glow-color); }

Indicator (.rack-slot-indicator)

.rack-slot-indicator { width: 4px; height: 20px; border-radius: 2px; background: var(--border-mid); flex-shrink: 0; }
.rack-slot.active .rack-slot-indicator { background: var(--amber); box-shadow: 0 0 6px var(--amber-glow); }

Label (.rack-slot-label)

.rack-slot-label { font-family: var(--font-ui); font-size: 10px; font-weight: 500; color: var(--text-secondary); letter-spacing: 1px; }
.rack-slot.active .rack-slot-label { color: var(--amber); }

HTML Structure

<div class="rack-panel">
  <div class="rack-slot active">
    <div class="rack-slot-indicator"></div>
    <span class="rack-slot-label">CHANNEL 1</span>
  </div>
  <div class="rack-slot">
    <div class="rack-slot-indicator"></div>
    <span class="rack-slot-label">CHANNEL 2</span>
  </div>
  <div class="rack-slot">
    <div class="rack-slot-indicator"></div>
    <span class="rack-slot-label">CHANNEL 3</span>
  </div>
  <div class="rack-slot">
    <div class="rack-slot-indicator"></div>
    <span class="rack-slot-label">AUX SEND</span>
  </div>
  <div class="rack-slot">
    <div class="rack-slot-indicator"></div>
    <span class="rack-slot-label">MASTER</span>
  </div>
</div>

Size Variants

No size variants defined.

Material Variants

No material variants. Uses standard raised surface with deep shadow.

Theme Behavior

• Background swaps via --bg-raised token
• Active indicator always uses --amber with amber glow
• Inactive indicator uses --border-mid (adapts to theme)
• Label color swaps between --text-secondary (inactive) and --amber (active)

Constraints

1. MUST include 4px vertical LED indicator on left edge of each slot
2. Active channel indicator MUST glow amber (0 0 6px var(--amber-glow))
3. Inactive indicators MUST show as dim lines (--border-mid), not hidden
4. Slots MUST be separated by --border-subtle bottom borders
5. MUST use fixed 200px width (rack module standard proportion)
6. MUST NOT use horizontal scroll -- content is vertical-only

Accessibility

• Container should have role="navigation" or role="tablist" with aria-orientation="vertical"
• Slots should have role="tab" or be <button> elements
• Active slot: aria-selected="true" or aria-current="true"
• Support Up/Down arrow key navigation