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

/* Base theme container — hidden by default */
.theme {
  display: none;
  height: 100vh;
  width: 100%;
  align-items: center;
  justify-content: center;
  flex-direction: column;
  text-align: center;
  overflow: hidden;
  position: relative;
}

/* ==== 1. CRT GREEN ==== */
.crt {
  background-color: #0a0a0a;
  color: #00ff66;
  font-family: "VT323", monospace;
  letter-spacing: 1px;
  font-size: 1.6rem;
}
.crt::before {
  content: "";
  position: absolute;
  inset: 0;
  background: repeating-linear-gradient(
    to bottom,
    rgba(255, 255, 255, 0.03) 0px,
    rgba(255, 255, 255, 0.03) 1px,
    transparent 2px,
    transparent 3px
  );
  pointer-events: none;
}
.crt::after {
  content: "";
  position: absolute;
  inset: 0;
  background: radial-gradient(ellipse at center, rgba(255,255,255,0.04), transparent 70%);
  mix-blend-mode: overlay;
  animation: flicker 3s infinite;
}
.crt .text {
  z-index: 2;
  text-shadow: 0 0 6px rgba(0, 255, 102, 0.8), 0 0 20px rgba(0, 255, 102, 0.4);
}
.blink { animation: blink 1.2s steps(2, start) infinite; }

/* ==== 2. WINDOWS 95 BLUE ==== */
.win95 {
  background-color: #001a80;
  color: #ffffff;
  font-family: "Courier New", monospace;
}
.win95 .bar {
  width: 240px;
  height: 16px;
  background: #000;
  border: 2px solid #fff;
  margin-top: 2rem;
  position: relative;
  overflow: hidden;
}
.win95 .progress {
  background: #00ffff;
  height: 100%;
  width: 0%;
  animation: load 5s linear infinite;
}

/* ==== 3. AMBER TERMINAL ==== */
.amber {
  background-color: #120800;
  color: #ffb347;
  font-family: "Share Tech Mono", monospace;
  letter-spacing: 1px;
}
.amber h1 {
  text-shadow: 0 0 8px #ffb347;
}
.amber p { color: #ffddaa; }
.amber .cursor {
  display: inline-block;
  width: 12px;
  height: 20px;
  background: #ffb347;
  margin-left: 5px;
  animation: blink 1s steps(2, start) infinite;
}

/* ==== 4. MACINTOSH MONO ==== */
.mac {
  background-color: #f1f1f1;
  color: #000;
  font-family: "Courier New", monospace;
  border-top: 4px solid #000;
}
.mac h1 {
  border: 2px solid #000;
  padding: 1rem 2rem;
  box-shadow: 4px 4px 0 #000;
  margin-bottom: 1rem;
}

/* ==== 5. VHS STATIC ==== */
.vhs {
  background: #0b0b0b;
  color: #fff;
  font-family: "Press Start 2P", cursive;
  text-transform: uppercase;
  font-size: 0.9rem;
}
.vhs .static {
  position: absolute;
  width: 100%;
  height: 100%;
  background: repeating-linear-gradient(
    to bottom,
    rgba(255,255,255,0.05) 0px,
    rgba(255,255,255,0.05) 1px,
    transparent 2px
  );
  mix-blend-mode: screen;
  animation: static 0.3s infinite;
}

/* Common footer */
footer {
  position: absolute;
  bottom: 15px;
  font-size: 0.8rem;
  opacity: 0.7;
}

/* Animations */
@keyframes flicker {
  0%,19%,21%,23%,25%,54%,56%,100% { opacity: 1; }
  20%,24%,55% { opacity: 0.6; }
}
@keyframes blink { to { visibility: hidden; } }
@keyframes load {
  0% { width: 0%; }
  50% { width: 80%; }
  100% { width: 0%; }
}
@keyframes static {
  0% { transform: translateY(0); }
  100% { transform: translateY(3px); }
}