body {
  margin: 0;
  font-family: "Noto Sans TC", sans-serif;
  background-color: #f5f5f5;
}

.index-container {
  max-width: 400px;
  margin: 100px auto 0 auto;
  background: #f8fafc;
  padding: 40px 32px 32px 32px;
  border-radius: 16px;
  box-shadow: 0 2px 12px rgba(44,62,80,0.09);
  text-align: center;
}

.index-container h1 {
  color: #2c3e50;
  font-size: 2rem;
  margin-bottom: 18px;
  letter-spacing: 2px;
}

.index-desc {
  color: #555;
  font-size: 1.1rem;
  margin-bottom: 32px;
}

.index-btn-group {
  display: flex;
  justify-content: center;
  gap: 18px;
}

.index-btn {
  display: inline-block;
  padding: 12px 36px;
  background: #2c3e50;
  color: #fff;
  border: none;
  border-radius: 6px;
  font-size: 1rem;
  letter-spacing: 2px;
  text-decoration: none;
  font-weight: 500;
  transition: background 0.2s;
  cursor: pointer;
}

.index-btn:hover {
  background: #1a242f;
}

.index-btn-outline {
  background: #fff;
  color: #2c3e50;
  border: 2px solid #2c3e50;
}

.index-btn-outline:hover {
  background: #f5f5f5;
  color: #1a242f;
  border-color: #1a242f;
}

.logo-img {
  border-radius: 16px; /* 圓角 16px */
  box-shadow: 0 2px 8px rgba(44,62,80,0.08); /* 陰影效果 */
  display: block; /* 當作區塊元素，方便置中 */
  margin: 0 auto 24px auto; /* 上 0、左右自動置中、下 24px */
  max-width: 900px; /* 最大寬度 */
  min-width: 240px; /* 最小寬度 */
  width: 100%; /* 寬度填滿容器 */
  height: auto; /* 高度等比例縮放 */
}


.privacy-link,
.footer-link {
  font-size: 14px;
  color: #2c3e50;
  text-decoration: underline;
  transition: color 0.2s;
}

.privacy-link:hover,
.footer-link:hover {
  color: #1a242f;
}

.app-purpose-section {
  background-color: #f0f4f8;
  padding: 40px 20px;
  border-radius: 12px;
  max-width: 900px;
  margin: 60px auto;
  font-family: 'Noto Sans TC', sans-serif;
  color: #2c3e50;
  font-size: 0.95em;
  text-align: center;
  transition: padding-bottom 0.2s;
}

.app-purpose-section h2 {
  font-size: 28px;
  font-weight: bold;
  margin-bottom: 20px;
  text-align: center;
}

.app-purpose-section p {
  font-size: 18px;
  line-height: 1.8;
  margin-bottom: 16px;
}

.app-purpose-section ul {
  font-size: 18px;
  line-height: 1.8;
  margin-left: 1.5em;
  list-style-type: disc;
}

.app-purpose-section .disclaimer {
  font-size: 16px;
  color: #555;
  margin-top: 24px;
}

.app-purpose-toggle {
  font-size: 24px;
  font-weight: bold;
  cursor: pointer;
  text-align: center;
  border-bottom: 1px solid #ccc;
  padding-bottom: 6px;
  margin-bottom: 14px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.app-purpose-content {
  margin-top: 16px;
  font-size: 17px;
  line-height: 1.8;
  text-align: center;
  margin: 0 auto;
  display: inline-block;
  max-width: 600px;
}

.app-purpose-content ul {
  margin-left: 1.5em;
  list-style-type: disc;
  display: inline-block;
  text-align: left;
  margin: 0 auto 1em auto;
  font-size: 0.95em;
}

.app-purpose-content .disclaimer {
  font-size: 0.9em;
  color: #888;
  margin-top: 1em;
  text-align: center;
}

.hidden {
  display: none;
}

.site-footer p {
  text-align: center;
}

/* 當內容隱藏時，底框高度貼近標題 */
.app-purpose-content.hidden {
  padding: 0 !important;
  margin: 0 !important;
  height: 0;
  min-height: 0;
  max-height: 0;
  overflow: hidden;
}
/* 應用說明外框 */
.app-purpose-box {
  background-color: #f9f9f9;
  padding: 24px;
  border-radius: 18px;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.06);
  max-width: 860px;
  margin: 40px auto 60px;
}

/* 收合按鈕 */
.app-purpose-toggle {
  font-size: 1.4em;
  cursor: pointer;
  border-bottom: 1px solid #ccc;
  padding-bottom: 6px;
  margin-bottom: 14px;
  display: flex;
  align-items: center;
  justify-content: center;
}

/* 箭頭動畫 */
#toggle-arrow {
  font-size: 1.2em;
  margin-left: 8px;
  transition: transform 0.3s ease;
}

/* 收合內容 */
.app-purpose-content.hidden {
  display: none;
}

/* 內文清單 */
.app-purpose-content ul {
  margin-left: 1.2em;
}

/* 免責聲明 */
.disclaimer {
  margin-top: 16px;
  font-size: 0.9em;
  color: #777;
}
/* 初始狀態：展開與收合動畫容器 */
.app-purpose-content {
  overflow: hidden;
  max-height: 0;
  opacity: 0;
  transition: max-height 0.4s ease, opacity 0.4s ease;
}

/* 展開狀態 */
.app-purpose-content.show {
  max-height: 1000px; /* 足夠包住內容即可，不夠可再調大 */
  opacity: 1;
}

/* 箭頭旋轉動畫（選配） */
#toggle-arrow.rotate {
  transform: rotate(180deg);
  transition: transform 0.3s ease;
}