body {
  font-family: sans-serif;
  background: #eee;
  margin: 0;
  padding: 1em;
}

h1 {
  margin: 0;
}

.subtitle {
  color: #555;
  margin-bottom: 1em;
}

#park {
  position: relative;
  height: 70vh;
  background: #f5f5f0;
  border: 2px solid #ccc;
  overflow: hidden;
  width: 100%;
  max-width: 600px;
}

/* 鳩（時） */
.bird {
  position: absolute;
  font-size: 100px;
}

/* フン（分） */
.poop {
  position: absolute;
  font-size: 18px;
  opacity: 0.6;
}

/* 豆（秒） */
.bean {
  position: absolute;
  font-size: 14px;
  opacity: 0.5;
  transition: opacity 0.8s;
}

.hidden {
  opacity: 0;
}



@media (max-width: 600px) {
  .bird { font-size: 80px; }
}


@media (max-width: 600px) {
  .bird { font-size: 22px; }
  .poop { font-size: 14px; }
  .bean { font-size: 10px; }
}