Background/Foreground effect going away when scrolling

Question

Apologies if the answer is obvious--still very new to CSS and Twine.

I found a cool CRT monitor effect which mostly works great with my game, but one problem: any time I have a passage that goes long and requires scrolling, the background/foreground flickering effect does not carry over past the page break.

I've messed around with all the CSS settings I could think of, but I'm not able to make any type of scrolling work with the effect. Was hoping you folks may have an idea.

Here is the code for reference:

@keyframes flicker {
  0% {
    opacity: 0.27861;
  }
  5% {
    opacity: 0.34769;
  }
  10% {
    opacity: 0.23604;
  }
  15% {
    opacity: 0.90626;
  }
  20% {
    opacity: 0.18128;
  }
  25% {
    opacity: 0.83891;
  }
  30% {
    opacity: 0.65583;
  }
  35% {
    opacity: 0.67807;
  }
  40% {
    opacity: 0.26559;
  }
  45% {
    opacity: 0.84693;
  }
  50% {
    opacity: 0.96019;
  }
  55% {
    opacity: 0.08594;
  }
  60% {
    opacity: 0.20313;
  }
  65% {
    opacity: 0.71988;
  }
  70% {
    opacity: 0.53455;
  }
  75% {
    opacity: 0.37288;
  }
  80% {
    opacity: 0.71428;
  }
  85% {
    opacity: 0.70419;
  }
  90% {
    opacity: 0.7003;
  }
  95% {
    opacity: 0.36108;
  }
  100% {
    opacity: 0.24387;
  }
}
@keyframes textShadow {
  0% {
    text-shadow: 0.4389924193300864px 0 1px rgba(0,30,255,0.5), -0.4389924193300864px 0 1px rgba(255,0,80,0.3), 0 0 3px;
  }
  5% {
    text-shadow: 2.7928974010788217px 0 1px rgba(0,30,255,0.5), -2.7928974010788217px 0 1px rgba(255,0,80,0.3), 0 0 3px;
  }
  10% {
    text-shadow: 0.02956275843481219px 0 1px rgba(0,30,255,0.5), -0.02956275843481219px 0 1px rgba(255,0,80,0.3), 0 0 3px;
  }
  15% {
    text-shadow: 0.40218538552878136px 0 1px rgba(0,30,255,0.5), -0.40218538552878136px 0 1px rgba(255,0,80,0.3), 0 0 3px;
  }
  20% {
    text-shadow: 3.4794037899852017px 0 1px rgba(0,30,255,0.5), -3.4794037899852017px 0 1px rgba(255,0,80,0.3), 0 0 3px;
  }
  25% {
    text-shadow: 1.6125630401149584px 0 1px rgba(0,30,255,0.5), -1.6125630401149584px 0 1px rgba(255,0,80,0.3), 0 0 3px;
  }
  30% {
    text-shadow: 0.7015590085143956px 0 1px rgba(0,30,255,0.5), -0.7015590085143956px 0 1px rgba(255,0,80,0.3), 0 0 3px;
  }
  35% {
    text-shadow: 3.896914047650351px 0 1px rgba(0,30,255,0.5), -3.896914047650351px 0 1px rgba(255,0,80,0.3), 0 0 3px;
  }
  40% {
    text-shadow: 3.870905614848819px 0 1px rgba(0,30,255,0.5), -3.870905614848819px 0 1px rgba(255,0,80,0.3), 0 0 3px;
  }
  45% {
    text-shadow: 2.231056963361899px 0 1px rgba(0,30,255,0.5), -2.231056963361899px 0 1px rgba(255,0,80,0.3), 0 0 3px;
  }
  50% {
    text-shadow: 0.08084290417898504px 0 1px rgba(0,30,255,0.5), -0.08084290417898504px 0 1px rgba(255,0,80,0.3), 0 0 3px;
  }
  55% {
    text-shadow: 2.3758461067427543px 0 1px rgba(0,30,255,0.5), -2.3758461067427543px 0 1px rgba(255,0,80,0.3), 0 0 3px;
  }
  60% {
    text-shadow: 2.202193051050636px 0 1px rgba(0,30,255,0.5), -2.202193051050636px 0 1px rgba(255,0,80,0.3), 0 0 3px;
  }
  65% {
    text-shadow: 2.8638780614874975px 0 1px rgba(0,30,255,0.5), -2.8638780614874975px 0 1px rgba(255,0,80,0.3), 0 0 3px;
  }
  70% {
    text-shadow: 0.48874025155497314px 0 1px rgba(0,30,255,0.5), -0.48874025155497314px 0 1px rgba(255,0,80,0.3), 0 0 3px;
  }
  75% {
    text-shadow: 1.8948491305757957px 0 1px rgba(0,30,255,0.5), -1.8948491305757957px 0 1px rgba(255,0,80,0.3), 0 0 3px;
  }
  80% {
    text-shadow: 0.0833037308038857px 0 1px rgba(0,30,255,0.5), -0.0833037308038857px 0 1px rgba(255,0,80,0.3), 0 0 3px;
  }
  85% {
    text-shadow: 0.09769827255241735px 0 1px rgba(0,30,255,0.5), -0.09769827255241735px 0 1px rgba(255,0,80,0.3), 0 0 3px;
  }
  90% {
    text-shadow: 3.443339761481782px 0 1px rgba(0,30,255,0.5), -3.443339761481782px 0 1px rgba(255,0,80,0.3), 0 0 3px;
  }
  95% {
    text-shadow: 2.1841838852799786px 0 1px rgba(0,30,255,0.5), -2.1841838852799786px 0 1px rgba(255,0,80,0.3), 0 0 3px;
  }
  100% {
    text-shadow: 2.6208764473832513px 0 1px rgba(0,30,255,0.5), -2.6208764473832513px 0 1px rgba(255,0,80,0.3), 0 0 3px;
  }
}
.crt::after {
  content: " ";
  display: block;
  position: absolute;
  top: 0;
  left: 0;
  bottom: 0;
  right: 0;
  background: rgba(18, 16, 16, 0.1);
  opacity: 0;
  z-index: 2;
  pointer-events: none;
  animation: flicker 0.15s infinite;
}
.crt::before {
  content: " ";
  display: block;
  position: absolute;
  top: 0;
  left: 0;
  bottom: 0;
  right: 0;
  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));
  z-index: 2;
  background-size: 100% 2px, 3px 100%;
  pointer-events: none;
}
.crt {
  animation: textShadow 1.6s infinite;
}

Currently using Twine Version 2.2.1 and Sugarcube 2.21.0.

Thank you for your help!

Answer 1

Change position of .crt::after and ::before from absolute to fixed.

Comments

@andything

You didn't state if the CRT effect was going to be applied to the whole of a passage's content or or only a selective area of it. Nor didn't you state if you wanted to apply the CRT effect to every passage in your project or only to a selective few.

If the CRT effect is being applied to the whole of the passage's content then you may want to consided the following:

1. If the CRT effect is to appear in every passage of your project.

You could change the .crt related CSS selectors to target the .passage class instead...

.passage::before {
  content: " ";
  display: block;
  position: fixed;
  top: 0;
  left: 0;
  bottom: 0;
  right: 0;
  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));
  z-index: 2;
  background-size: 100% 2px, 3px 100%;
  pointer-events: none;
}
.passage::after {
  content: " ";
  display: block;
  position: fixed;
  top: 0;
  left: 0;
  bottom: 0;
  right: 0;
  background: rgba(18, 16, 16, 0.1);
  opacity: 0;
  z-index: 2;
  pointer-events: none;
  animation: flicker 0.15s infinite;
}
.passage {
  animation: textShadow 1.6s infinite;
}

2. If the CRT effect is to appear in selected passages of your project.

You could assigned a known Passage Tag (like crt) to each of the passages you want the CRT effect to be applied to and then use CSS selectors similar to those in point 1 to target only the passages thus marked.

passage.crt::before {
  content: " ";
  display: block;
  position: fixed;
  top: 0;
  left: 0;
  bottom: 0;
  right: 0;
  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));
  z-index: 2;
  background-size: 100% 2px, 3px 100%;
  pointer-events: none;
}
.passage.crt::after {
  content: " ";
  display: block;
  position: fixed;
  top: 0;
  left: 0;
  bottom: 0;
  right: 0;
  background: rgba(18, 16, 16, 0.1);
  opacity: 0;
  z-index: 2;
  pointer-events: none;
  animation: flicker 0.15s infinite;
}
.passage.crt {
  animation: textShadow 1.6s infinite;
}

note: both of the above examples includes the position: fixed; change suggested by idling.

---

Thanks so much for your help greyelf and idling! You guys are awesome.

Should have been more clear: this will apply to all the passages, so the .passage class change combined with the position: fixed switch got this working exactly like I hoped.

Really appreciate the quick help on this.