body {
  margin: 0;
  font-family: 'Poppins', 'Noto Sans TC', sans-serif;
  background-color: #f9fafb;
}

/* ☰ 漢堡按鈕 */
.menu-btn {
  font-size: 28px;
  background: #2c3e50;
  border: none;
  color: white;
  cursor: pointer;
  padding: 16px 20px;
  position: fixed;
  top: 0;
  left: 0;
  z-index: 1002;
}

/* 側邊欄 */
.sidebar {
  position: fixed;
  top: 0;
  left: -240px;
  width: 220px;
  height: 100%;
  background-color: #2c3e50;
  color: white;
  padding-top: 60px;
  transition: left 0.3s ease;
  z-index: 1001;
}

.sidebar.show {
  left: 0;
}

.sidebar h2 {
  text-align: center;
  font-size: 1.4em;
  margin-bottom: 30px;
}

.sidebar a {
  display: block;
  padding: 14px 20px;
  color: white;
  text-decoration: none;
  transition: background-color 0.3s;
}

.sidebar a:hover {
  background-color: #34495e;
}

.sidebar a.active {
  background-color: #1abc9c;
  font-weight: bold;
}

/* 黑色遮罩背景 */
.overlay {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-color: rgba(0, 0, 0, 0.3);
  display: none;
  z-index: 1000;
}

.overlay.show {
  display: block;
}

/* 主內容 */
.content {
  padding: 100px 40px;
  max-width: 960px;
  margin: auto;
  line-height: 2;
  color: #2c3e50;
  transition: transform 0.3s ease, margin-left 0.3s ease;
  text-align: center;
}

.content.shift-right {
  transform: translateX(220px);
}

.content h1 {
  font-size: 3em;
  margin-bottom: 20px;
  font-weight: bold;
}

.content h2 {
  font-size: 1.8em;
  margin-bottom: 30px;
  color: #34495e;
}

/* 卡片樣式 */
.card-container {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 24px;
  margin-bottom: 40px;
}

.card {
  background-color: white;
  border-radius: 12px;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
  padding: 24px;
  width: 260px;
  transition: transform 0.3s, box-shadow 0.3s;
  text-align: left;
  animation: fadeSlideUp 0.6s ease forwards;
  opacity: 0;
}

.card:hover {
  transform: translateY(-5px);
  box-shadow: 0 8px 20px rgba(0, 0, 0, 0.15);
}

.card h3 {
  font-size: 1.3em;
  margin-bottom: 10px;
  color: #2c3e50;
}

.card p {
  font-size: 1em;
  color: #555;
}

/* 桌面版側邊欄常駐 */
@media (min-width: 768px) {
  .sidebar {
    left: 0;
  }

  .sidebar.show {
    left: 0;
  }

  .menu-btn {
    display: none;
  }

  .overlay {
    display: none !important;
  }

  .content {
    margin-left: 220px;
    transform: none !important;
  }
}

/* 動畫效果 */
@keyframes fadeSlideUp {
  0% {
    opacity: 0;
    transform: translateY(30px);
  }
  100% {
    opacity: 1;
    transform: translateY(0);
  }
}

.fade-in-title {
  opacity: 0;
  animation: fadeSlideUp 1s ease-out forwards;
  animation-delay: 0.2s;
  animation-fill-mode: forwards;
}

.fade-in-sub {
  opacity: 0;
  animation: fadeSlideUp 1s ease-out forwards;
  animation-fill-mode: forwards;
}
.contact-card {
  background-color: #ffffff;
  border-radius: 12px;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
  padding: 24px;
  max-width: 400px;
  margin: 40px auto;
  text-align: left;
  animation: fadeSlideUp 0.8s ease forwards;
  opacity: 0;
}

.contact-card p {
  font-size: 1.2em;
  margin: 12px 0;
  color: #2c3e50;
}

.contact-card strong {
  color: #1abc9c;
}
.teaching-card {
  background-color: #ffffff;
  border-radius: 12px;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
  padding: 32px 24px;
  max-width: 800px;
  margin: 40px auto;
  text-align: left;
  animation: fadeSlideUp 0.8s ease forwards;
  opacity: 0;
  line-height: 1.8;
  color: #2c3e50;
}

.teaching-card h3 {
  margin-top: 24px;
  margin-bottom: 12px;
  font-size: 1.4em;
  color: #1abc9c;
}

.teaching-card p,
.teaching-card li {
  font-size: 1.1em;
}

.teaching-card ul {
  padding-left: 20px;
  margin-top: 10px;
  margin-bottom: 20px;
}
.video-link {
  margin-top: 20px;
  text-align: center;
}

.video-link a {
  display: inline-block;
  padding: 10px 20px;
  background-color: #1abc9c;
  color: white;
  text-decoration: none;
  border-radius: 8px;
  transition: background-color 0.3s ease;
}

.video-link a:hover {
  background-color: #16a085;
}
.introduce-card {
  background-color: #ffffff;
  border-radius: 12px;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
  padding: 32px 24px;
  max-width: 800px;
  margin: 40px auto;
  text-align: left;
  animation: fadeSlideUp 0.8s ease forwards;
  opacity: 0;
  line-height: 1.8;
  color: #2c3e50;
}

.introduce-card h3 {
  margin-top: 24px;
  margin-bottom: 12px;
  font-size: 1.4em;
  color: #1abc9c;
}

.introduce-card p,
.introduce-card li {
  font-size: 1.1em;
}

.introduce-card ul {
  padding-left: 20px;
  margin-top: 10px;
  margin-bottom: 20px;
}