* {
  box-sizing: border-box;
}

html, body {
  margin: 0;
  padding: 0;
  height: 100%;
  background: #00B140;
  font-family: 'Segoe UI', sans-serif;
}

body {
  display: flex;
  justify-content: center;
  align-items: center;
  padding: 2vw;
}

/* Container */
#container {
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: center;
  background: rgba(255, 255, 255, 0.9); /* semi-transparent */
  border-radius: 30px;
  padding: 20px;
  width: 100%;
  height: 100%;
  aspect-ratio: 3 / 4;
  max-width: 800px;
  max-height: 95vh;
  box-shadow: 0 0 20px rgba(0,0,0,0.15);
  overflow: hidden;
  gap: 1rem;
}

/* Optional background overlay */
#container::before {
  content: "";
  position: absolute;
  top: 0; left: 0;
  width: 100%;
  height: 100%;
  background-size: cover;
  background-position: center;
  opacity: 0.2;
  z-index: 0;
}

#container > * {
  position: relative;
  z-index: 1;
}

h1 {
  margin: 10px 0;
  font-size: clamp(1.5rem, 4vw, 2em);
  text-align: center;
}

/* Back arrow */
#backArrow {
  position: absolute;
  top: 20px;
  left: 20px;
  font-size: 2rem;
  text-decoration: none;
  color: #4caf50;
  opacity: 0.7;
  transition: opacity 0.2s, transform 0.2s;
  z-index: 20;
}

#backArrow:hover {
  opacity: 1;
  transform: translateY(-2px);
}

/* Color picker (round) */
#bgColorPicker {
  position: absolute;
  top: 20px;
  right: 20px;
  width: 50px;
  height: 50px;
  border: 2px solid #8e8383;
  border-radius: 50%;
  cursor: pointer;
  padding: 0;
  z-index: 20;
}

/* Progress bar */
#progressContainer {
  position: absolute;
  bottom: 30px; /* slightly above bottom for visibility on mobile */
  left: 10px;
  right: 10px;
  height: 12px;
  background: rgba(0,0,0,0.1);
  border-radius: 6px;
  overflow: hidden;
}

#levelDisplay {
  position: absolute;
  bottom: 50px;   /* places it just above the progress bar */
  left: 50%;
  transform: translateX(-50%);
  font-size: 1.2rem;
  font-weight: bold;
  color: #333;
  text-align: center;
  z-index: 10;
}

#progressBar {
  width: 0%;
  height: 100%;
  background: linear-gradient(90deg, #4caf50, #AEFF00);
  border-radius: 6px 0 0 6px;
  transition: width 0.3s ease;
  box-shadow: 0 1px 3px rgba(0,0,0,0.2);
}