body {
  margin: 0;
  padding: 0;
  font-family: 'Roboto', sans-serif;
  background: #f5f5f5;
  color: #333;
}

a {
  text-decoration: none;
  color: inherit;
}

a img {
  border: none;
  outline: none;
}

a:link,
a:visited,
a:hover,
a:active {
  color: #454545;
}

.header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1em;
  font-size: 18px;
  background-color: #efeded;
  color: #575757;
  text-align: center;
}

.header-bottom-line {
  width: 100%;
  height: 3px;
  background: linear-gradient(to right,#f59090,#fcd7a1,#fff9b1,#a5d4ad,#a3bce2,#a59aca,#cfa7cd) 0 / 200%;
  animation: 5s rainbow_line linear infinite;
  flex: 1;
  margin: 0;
}

@keyframes rainbow_line {
  100% { background-position: 200%; }
}

.title-container {
  display: flex;
  align-items: center;
  justify-content: center;
}

.title-icon {
  margin-right: 10px;
  width: 50px;
  height: 50px;
  border: 3px solid #dbdbdb;
  border-radius: 50%;
}

.title-text {
  align-self: center;
}

.footer {
  font-size: 12px;
  border: 1px solid #dbdbdb;
  background-color: #e5e5e5;
  color: #575757;
  text-align: center;
  padding: 10px;
}

.social-media {
  display: flex;
  justify-content: center;
  gap: 10px;
  padding-top: 10px;
}

.social-media > a {
  margin: 0 10px 0 0;
}

/* リンクを全体に広げてクリック可能に */
.title-link {
  display: inline-flex;
  text-decoration: none;
  color: inherit;
  align-items: center;
}

/* モバイルでも誤タップしにくくする */
.title-link:active,
.title-link:focus {
  opacity: 0.8;
}

/* マウスホバー時の視覚フィードバック */
.title-link:hover .title-text {
  text-decoration: underline;
  color: #3c8ade;
}

.title-link,
.title-container {
  max-width: 100%;
  overflow: hidden;
}