* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
  line-height: 1.6;
  color: #c4c4c4;
  background: #030303;
  padding: 2rem;
}

header {
  text-align: center;
  margin-bottom: 3rem;
}

header h1 {
  font-size: 2.5rem;
  color: #c4c4c4;
  margin-bottom: 0.5rem;
}

header p {
  color: #808080;
}

.iframe-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 2rem;
  max-width: 1200px;
  margin: 0 auto;
}

.iframe-card {
  background: #111111;
  padding: 1.5rem;
  border-radius: 10px;
  border: 1px solid #1e1e1e;
  box-shadow: 0 4px 6px rgba(0, 0, 0, 0.3);
  transition: transform 0.3s ease;
}

.iframe-card:hover {
  transform: translateY(-5px);
  border-color: #2e2e2e;
}

.iframe-card h2 {
  font-size: 1.25rem;
  margin-bottom: 1rem;
  color: #c4c4c4;
}

iframe {
  border-radius: 5px;
  max-width: 100%;
  border: 1px solid #1e1e1e;
}

footer {
  text-align: center;
  margin-top: 3rem;
  padding: 1rem;
  color: #808080;
  font-size: 0.9rem;
}

.filter-container {
  text-align: center;
  margin-bottom: 2rem;
  padding: 1rem;
  background: #111111;
  border-radius: 10px;
  border: 1px solid #1e1e1e;
  max-width: 1200px;
  margin: 0 auto 2rem auto;
}

.filter-btn {
  background: #1e1e1e;
  color: #c4c4c4;
  border: 1px solid #2e2e2e;
  padding: 0.5rem 1rem;
  margin: 0.25rem;
  border-radius: 5px;
  cursor: pointer;
  transition: all 0.3s ease;
}

.filter-btn:hover {
  background: #2e2e2e;
  transform: translateY(-2px);
}

.filter-btn.active {
  background: #3e3e3e;
  border-color: #c4c4c4;
}

.lazy-loading {
  background: #1a1a1a;
  display: flex;
  align-items: center;
  justify-content: center;
  color: #808080;
  position: relative;
}

.lazy-loading::before {
  content: 'Click to load content...';
  position: absolute;
  font-size: 0.9rem;
}

@media (max-width: 768px) {
  body {
    padding: 1rem;
  }
  
  header h1 {
    font-size: 2rem;
  }
  
  .iframe-grid {
    gap: 1rem;
  }
  
  .filter-container {
    padding: 0.5rem;
    overflow-x: auto;
    white-space: nowrap;
    -webkit-overflow-scrolling: touch;
  }
  
  .filter-btn {
    padding: 0.4rem 0.8rem;
    font-size: 0.9rem;
  }
}

.iframe-card iframe.giphy-embed {
  background: #000;
}

.iframe-card iframe[src*="google.com/maps"] {
  border-radius: 8px;
}

.iframe-card iframe[src*="codepen.io"] {
  background: #1d1d1d;
}

.iframe-card iframe[src*="figma.com"] {
  background: #1e1e1e;
}

.iframe-card iframe[src*="behance.net"] {
  background: #1a1a1a;
}

.iframe-card iframe[src*="sketchfab.com"] {
  background: #000;
}

.iframe-card iframe[src*="observablehq.com"] {
  background: #1a1a1a;
}

.iframe-card iframe[src*="miro.com"] {
  background: #1e1e1e;
}

.iframe-card iframe[src*="discord.com"] {
  background: #36393f;
}

.iframe-card iframe[src*="prezi.com"] {
  background: #000;
}

.iframe-card iframe[src*="docs.google.com"] {
  background: #202124;
}

.iframe-card iframe[src*="scratch.mit.edu"] {
  background: #222;
}

.iframe-card iframe[src*="chess.com"] {
  background: #262421;
}

.iframe-card iframe[src*="jsfiddle.net"] {
  background: #1d1f21;
}

.iframe-card iframe[src*="desmos.com"] {
  background: #1a1a1a;
}

.iframe-card iframe[src*="geogebra.org"] {
  background: #222;
}

.iframe-card iframe[src*="kahoot.it"] {
  background: #2d2d2d;
}

.iframe-card iframe[src*="wolframalpha.com"] {
  background: #1a1a1a;
}

.iframe-card iframe[src*="replit.com"] {
  background: #1d2333;
}

.iframe-card iframe[src*="p5js.org"] {
  background: #1e1e1e;
}

.iframe-card iframe[src*="unity.com"] {
  background: #1f1f1f;
}

.iframe-card iframe[src*="khanacademy.org"] {
  background: #1a1a1a;
}

.iframe-card iframe[src*="tinkercad.com"] {
  background: #202020;
}

.iframe-card iframe[src*="translate.google.com"] {
  background: #202124;
}

.iframe-card iframe[src*="code.org"] {
  background: #1d1d1d;
}

.iframe-card iframe[src*="canva.com"] {
  background: #18191a;
}

.iframe-card iframe[src*="adobe.com"] {
  background: #1e1e1e;
}

.iframe-card iframe[src*="office.live.com"] {
  background: #252423;
}

.iframe-card iframe[src*="duolingo.com"] {
  background: #1f1f1f;
}

.iframe-card iframe[src*="nasa.gov"] {
  background: #000;
}

.iframe-card iframe[src*="windy.com"] {
  background: #1a1a1a;
}

.iframe-card iframe[src*="mcapi.us"] {
  background: #1a1a1a;
}

.iframe-card iframe[src*="earth.google.com"] {
  background: #000;
}

.iframe-card iframe[src*="mars.nasa.gov"] {
  background: #000;
}

.iframe-card iframe[src*="marinetraffic.com"] {
  background: #1a1a1a;
}

.iframe-card iframe[src*="flightradar24.com"] {
  background: #1e1e1e;
}

.iframe-card iframe[src*="bbc.com"] {
  background: #1a1a1a;
}

.iframe-card iframe[src*="onlinepianist.com"] {
  background: #1e1e1e;
}

.iframe-card iframe[src*="lichess.org"] {
  background: #1d1d1d;
}

.iframe-card iframe[src*="wikistream.wmflabs.org"] {
  background: #1a1a1a;
}

.iframe-card iframe[src*="ustream.tv"] {
  background: #000;
}

.iframe-card iframe[src*="blooket.com"] {
  background: #1a1a1a;
}

.loading {
  position: relative;
}

.loading::after {
  content: 'Loading...';
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  background: #111111;
  padding: 0.5rem 1rem;
  border-radius: 4px;
  border: 1px solid #1e1e1e;
  color: #c4c4c4;
}