:root {
  --bg: #f7fbff;
  --card: #ffffff;
  --accent: #2b6cb0;
  --muted: #6b7280;
  --btn-view: #2b6cb0;
  --btn-code: #6b7280;
  --btn-ppt: #166534;
}

* {
  box-sizing: border-box;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Noto Sans TC', 'PingFang TC', 'Microsoft JhengHei', Arial, sans-serif;
  margin: 0;
  background: var(--bg);
  color: #0f172a;
}

.container {
  max-width: 1000px;
  margin: 0 auto;
  padding: 24px;
}

.site-header {
  background: linear-gradient(90deg, #e6f0fb, #ffffff);
  border-bottom: 1px solid rgba(0, 0, 0, 0.05);
  text-align: center;
}

.site-header h1 {
  margin: 0;
  padding: 28px 0 4px;
  font-size: 28px;
}

.subtitle {
  margin: 0 0 20px;
  color: var(--muted);
}

.grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 22px;
  margin-top: 22px;
}

.week-card {
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: flex-start;
  gap: 8px;
  padding: 20px;
  background: var(--card);
  border-radius: 14px;
  box-shadow: 0 6px 18px rgba(17, 24, 39, 0.06);
  transition: transform .16s ease, box-shadow .16s ease;
}

.week-card:hover {
  transform: translateY(-6px);
  box-shadow: 0 12px 30px rgba(17, 24, 39, 0.08);
}

.week-number {
  font-weight: 700;
  color: var(--accent);
  font-size: 15px;
}

.week-title {
  font-size: 20px;
  font-weight: 600;
  color: #071133;
}

.buttons {
  margin-top: 10px;
  display: flex;
  flex-wrap: wrap; /* 增加換行彈性 */
  gap: 10px;
}

.btn {
  display: inline-block;
  padding: 8px 14px;
  border-radius: 8px;
  text-decoration: none;
  color: white;
  font-weight: 600;
  font-size: 14px;
  transition: background 0.2s ease;
}

.btn.view {
  background: var(--btn-view);
}

.btn.view:hover {
  background: #1e4e8c;
}

.btn.code {
  background: var(--btn-code);
}

.btn.code:hover {
  background: #4b5563;
}


.btn.ppt {
  background: var(--btn-ppt); 

.btn.ppt:hover {
  background: #14532d; /* 滑鼠移上去時的深色 */
}

.site-footer {
  padding: 18px 0;
  color: var(--muted);
  font-size: 14px;
  text-align: center;
  margin-top: 40px;
}

@media (max-width: 520px) {
  .site-header h1 {
    font-size: 22px;
  }

  .week-card {
    padding: 16px;
  }

  .btn {
    padding: 6px 10px;
    font-size: 13px;
  }
}