html, body {
  margin: 0;
  padding: 0;
  height: 100%;
  width: 100%;
  overflow: hidden;
  font-family: 'Segoe UI', sans-serif;
  background: transparent;
}

body.light {
  background-color: #ffffffF2; /* white with 95% opacity */
}

body.dark {
  background-color: #000000F2; /* black with 95% opacity */
}

/* Overlay container */
#overlay {
  width: 100vw;
  height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
  padding: 0;
  box-sizing: border-box;
}

/* Embedded GPT iframe */
#gpt-frame {
  width: 96vw;
  height: 92vh;
  max-width: 960px;
  border: none;
  border-radius: 12px;
  box-shadow: 0 0 30px rgba(0, 0, 0, 0.25);
  transition: all 0.3s ease-in-out;
}

/* Responsive adjustments for smaller screens */
@media screen and (max-width: 768px) {
  #gpt-frame {
    width: 100vw;
    height: 100vh;
    border-radius: 0;
  }
}