body {
  font-family: sans-serif;
  padding: 20px;
  background: #fafafa;
}

h1.main-title {
  font-size: 1.5em;
  margin-bottom: 5px;
}

.subtitle {
  font-size: 0.8em;
  color: #666;
}

.link-line {
  margin: 3px 0 20px;
  font-size: 1.1em;
}

.search-container {
  margin: 9px 0;
}

.search {
  margin-bottom: 15px;
  padding: 6px;
  font-size: 1em;
  width: 100%;
  max-width: 400px;
}

.msg {
  background: #f9f9f9;
  border-left: 4px solid #4CAF50;
  padding: 10px;
  margin-bottom: 15px;
  border-radius: 5px;
}

.date {
  color: #555;
  font-size: 0.9em;
  margin-bottom: 5px;
}

.title {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-weight: bold;
  cursor: pointer;
}

.arrow-container {
  margin-left: auto;
  display: flex;
  align-items: center;
  font-size: 0.8em;
  color: #333;
}

.arrow-text {
  margin-right: 5px;
}

.body {
  margin-top: 5px;
  display: none;
  line-height: 1.6;
  white-space: pre-wrap;
  font-size: 1em;
}

.arrow.open {
  transform: rotate(90deg);
}

/* ===== レスポンシブ：スマホ用 (500px以下) ===== */
@media screen and (max-width: 500px) {
h1.main-title {
  font-size: 1.5em;
  margin-bottom: 5px;
}

.subtitle {
  font-size: 0.8em;
  color: #666;
}

.link-line {
  margin: 3px 0 20px;
  font-size: 1.1em;
}

.search-container {
  margin: 9px 0;
}

.search {
  margin-bottom: 15px;
  padding: 6px;
  font-size: 1em;
  width: 100%;
  max-width: 400px;
}

.msg {
  background: #f9f9f9;
  border-left: 4px solid #4CAF50;
  padding: 10px;
  margin-bottom: 15px;
  border-radius: 5px;
}

.date {
  color: #555;
  font-size: 0.9em;
  margin-bottom: 5px;
}

.title {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-weight: bold;
  cursor: pointer;
}

.arrow-container {
  margin-left: auto;
  display: flex;
  align-items: center;
  font-size: 0.8em;
  color: #333;
}

.arrow-text {
  margin-right: 5px;
}

.body {
  margin-top: 5px;
  display: none;
  line-height: 1.6;
  white-space: pre-wrap;
  font-size: 1em;
}

.arrow.open {
  transform: rotate(90deg);
}