/* Body & full-screen setup */
body, html {
  margin: 0;
  padding: 0;
  height: 100%;
  width: 100%;
  font-family: 'Arial', sans-serif;
  background-color: #000;
  color: #fff;
  overflow: hidden;
}

/* Start screen */
#startScreen {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: linear-gradient(to bottom right, #1a1a1a, #000000);
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  text-align: center;
}

#startScreen h1 {
  font-size: 3em;
  margin-bottom: 20px;
}

#startScreen p {
  font-size: 1.2em;
  margin-bottom: 20px;
}

#startScreen select, #startScreen button {
  padding: 10px 20px;
  font-size: 1em;
  margin: 5px;
  border-radius: 12px;
  border: none;
  cursor: pointer;
  transition: all 0.2s ease-in-out;
}

#startScreen button:hover {
  transform: scale(1.05);
  background-color: #444;
}

/* Color training screen */
#colorBox {
  display: none;
  width: 100%;
  height: 100%;
  transition: background-color 0.5s ease;
}

#timer {
  display: none;
  position: absolute;
  top: 10px;
  right: 10px;
  font-size: 3em;
  font-weight: bold;
  background-color: rgba(0,0,0,0.4);
  padding: 15px 25px;
  border-radius: 25px;
  text-shadow: 2px 2px 8px #000;
}

/* Buttons */
#restartBtn, #muteBtn {
  border: none;
  border-radius: 20px;
  padding: 10px 20px;
  font-size: 1em;
  font-weight: bold;
  cursor: pointer;
  transition: all 0.2s ease-in-out;
  background-color: rgba(255,255,255,0.15);
  color: #fff;
  box-shadow: 0 4px 8px rgba(0,0,0,0.3);
}

#restartBtn:hover, #muteBtn:hover {
  background-color: rgba(255,255,255,0.3);
  transform: scale(1.1);
}

/* Footer */
#footerStart, #footerTraining {
  position: absolute;
  bottom: 10px;
  width: 100%;
  text-align: center;
  font-size: 1em;
  color: #aaa;
}