<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 800 1000" role="img" aria-label="Commercial lightning protection — a flat-roof business building ringed with air terminals tied to a roof conductor loop and down conductors to a ground ring, with surge protection at the service entrance">
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  <linearGradient id="cSky" x1="0" y1="0" x2="0" y2="1"><stop offset="0" stop-color="#0A1320"/><stop offset=".5" stop-color="#0E1726"/><stop offset="1" stop-color="#102031"/></linearGradient>
  <radialGradient id="cFlash" cx="38%" cy="9%" r="55%"><stop offset="0" stop-color="#9fe0ff" stop-opacity=".5"/><stop offset=".3" stop-color="#5BC3F0" stop-opacity=".15"/><stop offset="1" stop-color="#5BC3F0" stop-opacity="0"/></radialGradient>
  <linearGradient id="cWall" x1="0" y1="0" x2="1" y2="0"><stop offset="0" stop-color="#1C2E46"/><stop offset=".5" stop-color="#243A57"/><stop offset="1" stop-color="#172940"/></linearGradient>
  <linearGradient id="cRoof" x1="0" y1="0" x2="1" y2="0"><stop offset="0" stop-color="#22364F"/><stop offset="1" stop-color="#1A2C42"/></linearGradient>
  <linearGradient id="cBolt" x1="0" y1="0" x2="0" y2="1"><stop offset="0" stop-color="#eaf7ff"/><stop offset="1" stop-color="#5BC3F0"/></linearGradient>
  <linearGradient id="cGround" x1="0" y1="0" x2="0" y2="1"><stop offset="0" stop-color="#13233A"/><stop offset="1" stop-color="#0A1422"/></linearGradient>
  <pattern id="cGrid" width="40" height="40" patternUnits="userSpaceOnUse"><path d="M40 0H0V40" fill="none" stroke="#2FA8E0" stroke-opacity=".06"/></pattern>
  <filter id="cGlow" x="-60%" y="-60%" width="220%" height="220%"><feGaussianBlur stdDeviation="6" result="b"/><feMerge><feMergeNode in="b"/><feMergeNode in="SourceGraphic"/></feMerge></filter>
  <filter id="cSoft" x="-40%" y="-40%" width="180%" height="180%"><feGaussianBlur stdDeviation="2.2"/></filter>
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<rect width="800" height="1000" fill="url(#cSky)"/>
<rect width="800" height="1000" fill="url(#cGrid)"/>
<rect width="800" height="620" fill="url(#cFlash)"/>

<!-- strike -->
<g filter="url(#cGlow)">
  <path d="M250 20 L214 180 L250 172 L202 312 L238 304 L196 392"
        fill="none" stroke="url(#cBolt)" stroke-width="7" stroke-linejoin="round" stroke-linecap="round"/>
  <path d="M250 20 L214 180 L250 172 L202 312 L238 304 L196 392"
        fill="none" stroke="#fff" stroke-width="2.4" stroke-linejoin="round" stroke-linecap="round" opacity=".9"/>
  <path d="M228 220 L268 256 M214 296 L182 268" stroke="#bfeaff" stroke-width="2.6" fill="none" opacity=".65"/>
</g>

<!-- ground -->
<rect y="720" width="800" height="280" fill="url(#cGround)"/>
<path d="M0 720 Q400 700 800 720 L800 758 Q400 736 0 758 Z" fill="#16263E" opacity=".7"/>

<!-- BUILDING: flat-roof commercial -->
<g>
  <!-- roof slab (slight perspective) -->
  <path d="M150 430 L650 430 L690 470 L110 470 Z" fill="url(#cRoof)" stroke="#34506F" stroke-width="2"/>
  <rect x="110" y="470" width="580" height="250" fill="url(#cWall)" stroke="#34506F" stroke-width="2"/>
  <!-- parapet line -->
  <path d="M110 470 H690" stroke="#101D2E" stroke-width="2" opacity=".5"/>
  <!-- storefront glazing -->
  <g>
    <rect x="140" y="540" width="520" height="120" fill="#101D2E" opacity=".55"/>
    <g stroke="#2FA8E0" stroke-opacity=".18" stroke-width="2"><path d="M270 540 V660 M400 540 V660 M530 540 V660 M140 600 H660"/></g>
    <rect x="150" y="550" width="110" height="44" fill="#2FA8E0" opacity=".12"/>
    <rect x="410" y="550" width="110" height="44" fill="#2FA8E0" opacity=".12"/>
  </g>
  <!-- entrance -->
  <rect x="356" y="612" width="88" height="108" rx="3" fill="#0C1726" stroke="#34506F" stroke-width="2"/>
  <path d="M400 612 V720" stroke="#34506F" stroke-width="1.5"/>
  <!-- rooftop HVAC unit -->
  <rect x="430" y="396" width="90" height="36" rx="4" fill="#1A2C44" stroke="#34506F" stroke-width="2"/>
  <path d="M442 414 H508" stroke="#101D2E" stroke-width="2" opacity=".6"/>
</g>

<!-- AIR TERMINALS ringing the parapet -->
<g stroke="#9FB4CC" stroke-width="3.4" stroke-linecap="round">
  <line x1="160" y1="430" x2="160" y2="386"/>
  <line x1="300" y1="430" x2="300" y2="386"/>
  <line x1="400" y1="430" x2="400" y2="384"/>
  <line x1="500" y1="430" x2="500" y2="386"/>
  <line x1="640" y1="430" x2="640" y2="386"/>
</g>
<g fill="#F2B705">
  <circle cx="160" cy="382" r="5.5"/><circle cx="300" cy="382" r="5.5"/><circle cx="400" cy="380" r="6.5"/><circle cx="500" cy="382" r="5.5"/><circle cx="640" cy="382" r="5.5"/>
</g>
<circle cx="300" cy="382" r="12" fill="#F2B705" opacity=".25" filter="url(#cSoft)"/>

<!-- ROOF CONDUCTOR LOOP across all terminals -->
<path d="M160 382 H640" fill="none" stroke="#F2B705" stroke-width="3.4" stroke-linecap="round" opacity=".95"/>
<!-- step jog showing it's a cable on the parapet -->
<path d="M160 382 Q150 410 138 430" fill="none" stroke="#F2B705" stroke-width="3.4" stroke-linecap="round" opacity=".95"/>
<path d="M640 382 Q652 410 662 430" fill="none" stroke="#F2B705" stroke-width="3.4" stroke-linecap="round" opacity=".95"/>

<!-- DOWN CONDUCTORS at two corners -->
<path d="M138 470 L138 720 Q138 742 126 756" fill="none" stroke="#F2B705" stroke-width="3.4" stroke-linecap="round" opacity=".95"/>
<path d="M662 470 L662 720 Q662 742 674 756" fill="none" stroke="#F2B705" stroke-width="3.4" stroke-linecap="round" opacity=".95"/>

<!-- ground ring + electrodes -->
<path d="M126 770 Q400 752 674 770" fill="none" stroke="#F2B705" stroke-width="4" stroke-linecap="round"/>
<path d="M126 770 Q400 752 674 770" fill="none" stroke="#F2B705" stroke-width="3" stroke-dasharray="2 9" opacity=".8"/>
<g stroke="#C99405" stroke-width="5" stroke-linecap="round">
  <line x1="170" y1="772" x2="170" y2="846"/><line x1="400" y1="760" x2="400" y2="838"/><line x1="630" y1="772" x2="630" y2="846"/>
</g>
<g stroke="#F2B705" stroke-width="2" fill="none" opacity=".5"><path d="M400 838 q-20 24 -36 38 M400 838 q20 24 38 40"/></g>

<!-- surge protection box at service entrance -->
<rect x="690" y="600" width="36" height="74" rx="4" fill="#16243A" stroke="#34506F" stroke-width="2"/>
<rect x="697" y="610" width="22" height="6" rx="3" fill="#2FA8E0" opacity=".7"/>
<rect x="697" y="622" width="22" height="6" rx="3" fill="#F2B705" opacity=".7"/>
<rect x="697" y="634" width="16" height="6" rx="3" fill="#2FA8E0" opacity=".4"/>

<!-- labels -->
<g font-family="'JetBrains Mono',monospace" font-size="15" font-weight="600">
  <g><rect x="346" y="320" width="200" height="30" rx="6" fill="#0A1320" stroke="#2FA8E0" stroke-opacity=".5"/><text x="360" y="340" fill="#9fe0ff">ROOF CONDUCTOR</text></g>
  <g><rect x="600" y="660" width="92" height="30" rx="6" fill="#0A1320" stroke="#F2B705" stroke-opacity=".5"/><text x="612" y="680" fill="#F2B705">SURGE</text></g>
  <g><rect x="306" y="858" width="190" height="30" rx="6" fill="#0A1320" stroke="#F2B705" stroke-opacity=".5"/><text x="320" y="878" fill="#F2B705">GROUNDING RING</text></g>
</g>
</svg>
