html, body {
    margin: 0;
    padding: 0;
    height: 100%;
}

body {
    background-color: #000000;

    background-image:
        repeating-radial-gradient(
            circle at center,
            rgba(220, 0, 0, 0.25) 0px,
            rgba(220, 0, 0, 0.25) 2px,
            transparent 2px,
            transparent 70px
        ),
        repeating-conic-gradient(
            from 0deg,
            rgba(0, 80, 255, 0.15) 0deg,
            rgba(0, 80, 255, 0.15) 2deg,
            transparent 2deg,
            transparent 18deg
        );

    background-attachment: fixed;
    background-blend-mode: screen;
}

@keyframes pulseWeb {
    0%, 100% { filter: brightness(1); }
    50% { filter: brightness(1.15); }
}

body{
      margin:0;
      min-height:100vh;
      display:flex;
      justify-content:center;
      align-items:center;
      padding:20px;
      box-sizing:border-box;
      background:#000; /* optional */
    }
    .video-wrapper{
      width:70%;
      max-width:800px;
      aspect-ratio:16/9;
    }
    .video-wrapper iframe{
      width:100%;
      height:100%;
      border:0;
      border-radius:12px;
    }

    .back-button{
  position:absolute;
  top:20px;
  left:20px;
  padding:10px 20px;
  background:white;
  color:black;
  text-decoration:none;
  font-weight:bold;
  border-radius:8px;
  transition:0.2s ease;
}

.back-button:hover{
  background:#ddd;
}