body {
  font-family: 'Segoe UI', sans-serif;
  background-color: #f5fff5;
  color: #222;
  margin: 0;
  padding: 0;
}

header {
  background: #6cbf40; /* 黄緑 */
  color: white;
  text-align: center;
  padding: 1rem;
}

.intro {
  text-align: center;
  margin: 2rem;
}

.button {
  display: inline-block;
  background: #6cbf40;
  color: white;
  padding: 0.8rem 1.5rem;
  border-radius: 8px;
  text-decoration: none;
  font-weight: bold;
}

.button:hover {
  background: #59a935;
}

.chat-area {
  max-width: 800px;
  margin: 1rem auto;
  background: white;
  border-radius: 12px;
  padding: 1rem;
  height: 70vh;
  overflow-y: auto;
  box-shadow: 0 2px 6px rgba(0, 0, 0, 0.1);
}

/* 吹き出しレイアウト */
.user, .assistant {
  max-width: 70%;
  margin: 10px;
  padding: 10px 14px;
  border-radius: 12px;
  line-height: 1.5;
  word-wrap: break-word;
}

.user {
  background: #d3f9d8;
  align-self: flex-end;
  margin-left: auto;
  text-align: right;
  border-top-right-radius: 0;
}

.assistant {
  background: #e8f5e9;
  align-self: flex-start;
  margin-right: auto;
  text-align: left;
  border-top-left-radius: 0;
}

.input-area {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 8px;
  margin: 1rem;
}

textarea {
  width: 60%;
  padding: 10px;
  border-radius: 8px;
  border: 1px solid #ccc;
  resize: vertical;
  font-family: inherit;
  line-height: 1.4;
}

button {
  padding: 10px 15px;
  border: none;
  background: #6cbf40;
  color: white;
  border-radius: 8px;
  cursor: pointer;
}

button:hover {
  background: #59a935;
}

footer {
  text-align: center;
  font-size: 0.85rem;
  padding: 1rem;
  color: #555;
}