LED Dots

Physical Analog

Reference devices: Panel-mounted LED indicators on every piece of electronic equipment from this era. Mechanism: A through-hole LED (Light Emitting Diode) mounted in a front-panel hole with a clear or diffused lens cap. Standard sizes were 3mm and 5mm diameter. The LED emits light in a specific color determined by the semiconductor material: red (GaAsP), green (GaP), blue (GaN), amber (AlGaInP). The box-shadow glow simulates the LED light illuminating the surrounding panel surface. The .off state shows the LED's dark body (visible but not illuminated) -- real unlit LEDs appear as a dark gray/brown disc.

Geometry

CSS Recipe

Base (.led-dot)

.led-dot { display: inline-block; width: 8px; height: 8px; border-radius: 50%; vertical-align: middle; }

Color variants

.led-dot.green { background: var(--green-on); box-shadow: 0 0 6px var(--green-on); }
.led-dot.red { background: var(--red-alert); box-shadow: 0 0 6px var(--red-alert); }
.led-dot.blue { background: var(--blue-info); box-shadow: 0 0 6px var(--blue-info); }
.led-dot.amber { background: var(--amber); box-shadow: 0 0 6px var(--amber); }

Off state

.led-dot.off { background: var(--text-muted); opacity: 0.3; box-shadow: none; }

LED Cluster container

.led-cluster { display: flex; gap: 6px; padding: 6px 10px; background: var(--bg-inset); border: 1px solid var(--border-subtle); border-radius: var(--radius-sm); }
.led-cluster .led-dot { width: 6px; height: 6px; }

HTML Structure

<!-- Individual LEDs -->
<div class="led-dot green"></div>
<div class="led-dot red"></div>
<div class="led-dot blue"></div>
<div class="led-dot amber"></div>
<div class="led-dot off"></div>

<!-- LED Cluster -->
<div class="led-cluster">
  <div class="led-dot green"></div>
  <div class="led-dot green"></div>
  <div class="led-dot off"></div>
  <div class="led-dot red"></div>
</div>

Size Variants

• Default: 8x8px
• In cluster: 6x6px (automatically smaller)

Material Variants

Theme Behavior

• LED colors are constant across themes (accent colors don't change)
• Off state uses --text-muted which swaps between themes
• Glow effect remains constant (LEDs emit light regardless of ambient)

Constraints

1. MUST be perfectly circular (border-radius: 50%)
2. Active LEDs MUST have matching-color glow at 6px radius
3. Off LEDs MUST be visible (30% opacity muted) -- not hidden
4. Off LEDs MUST NOT have glow (box-shadow: none)
5. Glow uses the LED color directly (not a glow token with reduced opacity)
6. MUST use vertical-align: middle for inline alignment with text

Accessibility

• Include aria-label describing the LED state and meaning
• Example: aria-label="Channel 1: active" for a green LED
• Color alone must not be the only indicator -- provide context via adjacent labels
• Off LEDs should have aria-label indicating the off state