body {
  font-family: sans-serif;
  background: #e0f7fa;
  margin: 0;
  padding: 0;
  text-align: center;
}

h1 {
  font-family: 'Kiwi Maru', sans-serif;
  font-size: 1.8rem;
  font-weight: bold;
  background: #fff3f8;
  padding: 0.8em 1em;
  border-radius: 1em;
  display: inline-block;
  box-shadow: 0 4px 6px rgba(0,0,0,0.1);
  color: #37474f;
}

.container {
  padding: 2em 1em;
  max-width: 600px;
  margin: auto;
}

input[type="number"] {
  padding: 0.8em;
  width: 80%;
  font-size: 1.2em;
  margin: 1em 0;
}

button {
  padding: 0.8em 2em;
  font-size: 1.2em;
  background: #81d4fa;
  border: none;
  border-radius: 1em;
  color: #fff;
  cursor: pointer;
}

.bird-images img {
  width: 40px;
  margin: 2px;
}

.share-buttons {
  margin-top: 2em;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 10px;
}

/* 共通ボタンスタイル */
.share-buttons button {
  color: #fff;
  border: none;
  padding: 0.8em 2em;
  font-size: 1rem;
  border-radius: 1.5em;
  cursor: pointer;
  width: 220px;
  transition: background-color 0.3s ease;
}

/* X（旧Twitter）カラー */
.btn-x {
  background-color: #000;
}
.btn-x:hover {
  background-color: #333;
}

/* LINEカラー */
.btn-line {
  background-color: #00c300;
}
.btn-line:hover {
  background-color: #00a000;
}

/* Facebookカラー */
.btn-fb {
  background-color: #1877f2;
}
.btn-fb:hover {
  background-color: #155cc1;
}

#bird-fall-container {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  z-index: 1;
  overflow: hidden;
}

.falling-bird {
  position: absolute;
  top: -60px;
  opacity: 0.8;
  animation-name: birdFall;
  animation-timing-function: ease-in-out;
  animation-iteration-count: infinite;
}

@keyframes birdFall {
  0% {
    transform: translateY(0) rotate(0deg);
    opacity: 0.8;
  }
  100% {
    transform: translateY(120vh) rotate(360deg);
    opacity: 0;
  }
}

.corner-bird {
  position: fixed;
  right: 10px;
  bottom: 10px;
  width: 100px; /* サイズ調整可 */
  z-index: 1;
  pointer-events: none; /* クリックなどの邪魔にならないように */
}

.button-links {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 10px;
  margin: 20px auto;
}

.link-button {
  display: inline-block;
  background-color: #81d4fa;
  color: #fff;
  padding: 12px 24px;
  text-decoration: none;
  font-size: 1rem;
  border-radius: 1em;
  transition: background-color 0.3s;
  box-shadow: 0 2px 5px rgba(0,0,0,0.15);
  text-align: center;
  width: 90%;
  max-width: 300px;
}

.link-button:hover {
  background-color: #4fc3f7;
}

.bird-comment {
  position: relative;
  display: inline-block;
  background-color: #fff8f8;
  color: #6b4e4e;
  font-family: 'Kiwi Maru', sans-serif;
  font-size: 1.2rem;
  line-height: 1.6;
  padding: 16px 24px;
  margin: 2em auto;
  border-radius: 1em;
  box-shadow: 0 2px 5px rgba(0,0,0,0.15);
  text-align: center;
  width: 90%;
  max-width: 300px;
  animation: fadeInUp 0.8s ease-in-out;
}

/* 吹き出しの三角形（下中央） */
.bird-comment::after {
  content: "";
  position: absolute;
  bottom: -16px;
  left: 70%;
  transform: translateX(-50%);
  border: 8px solid transparent;
  border-top-color: #fff8f8;
}

@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}