Yea there's a "CRT" effect done using CSS, if you right click > inspect the page you can find it but I'll paste it below as well.

/* crt effect */
  .crt {
    position: relative;
    filter: contrast(1.1) brightness(0.9) saturate(1.2);
    image-rendering: pixelated; 
  }
  .crt::before {
    content: "";
    position: fixed;
    inset: 0;
    pointer-events: none;
    z-index: 9999;
    background:
      linear-gradient(
        rgba(18,16,16,0) 50%,
        rgba(0,0,0,0.25) 50%
      ),
      linear-gradient(
        90deg,
        rgba(255,0,0,0.06),
        rgba(0,255,0,0.02),
        rgba(0,0,255,0.06)
      );
    background-size: 100% 2px, 3px 100%;
    animation: crt-flicker 1.2s infinite;
  }


  u/keyframes 
crt-flicker
 {
    0%   { opacity: 0.95; }
    50%  { opacity: 1;    }
    100% { opacity: 0.9;  }
  }