(function () {
  'use strict';

  var SVG = [
    '<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 40 80" width="40" height="80">',
    // Exhaust flame
    '<path d="M13,65 Q20,80 27,65" fill="#f97316" opacity="0.85"/>',
    '<path d="M15,63 Q20,74 25,63" fill="#fbbf24"/>',
    // Fins
    '<path d="M11,53 L3,70 L14,58" fill="#a855f7"/>',
    '<path d="M29,53 L37,70 L26,58" fill="#a855f7"/>',
    // Body
    '<ellipse cx="20" cy="42" rx="11" ry="22" fill="#e879f9"/>',
    // Nose cone
    '<path d="M20,10 L10,32 L30,32 Z" fill="#c026d3"/>',
    // Window
    '<circle cx="20" cy="44" r="7" fill="#0ea5e9" opacity="0.82"/>',
    '<circle cx="22" cy="41" r="2.5" fill="white" opacity="0.35"/>',
    // Body highlight
    '<ellipse cx="15" cy="36" rx="3" ry="8" fill="white" opacity="0.15" transform="rotate(-15,15,36)"/>',
    '</svg>'
  ].join('');

  function isDark() {
    return document.documentElement.classList.contains('dark');
  }

  function launch() {
    if (!isDark()) { scheduleNext(); return; }

    var goRight  = Math.random() > 0.5;
    var topPct   = 6 + Math.random() * 72;
    var duration = (3.5 + Math.random() * 4).toFixed(1);

    var wrapper = document.createElement('div');
    wrapper.className = 'fairydust-wrapper ' + (goRight ? 'go-right' : 'go-left');
    wrapper.style.top = topPct + 'vh';
    wrapper.style.setProperty('--fly-duration', duration + 's');

    var rocket = document.createElement('div');
    rocket.className = 'fairydust-rocket';
    rocket.style.transform = 'rotate(' + (goRight ? 90 : -90) + 'deg)';
    rocket.innerHTML = SVG;

    wrapper.appendChild(rocket);
    document.body.appendChild(wrapper);

    wrapper.addEventListener('animationend', function (e) {
      if (e.animationName === 'fairydust-fly-right' ||
          e.animationName === 'fairydust-fly-left') {
        wrapper.remove();
      }
    });

    scheduleNext();
  }

  function scheduleNext() {
    setTimeout(launch, 250000 + Math.random() * 950000); // 250–1200 s
  }

})();