:root {
  --bg-dark: #0a0f1d;
  --bg-surface: #111827;
  --bg-card: #1f293d;
  --accent-cyan: #06b6d4;
  --accent-blue: #3b82f6;
  --accent-glow: rgba(6, 182, 212, 0.35);
  --text-main: #f8fafc;
  --text-muted: #94a3b8;
  --border-line: #334155;
}

* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Noto Sans TC", sans-serif;
  background-color: var(--bg-dark);
  color: var(--text-main);
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* 導覽列 */
header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(10, 15, 29, 0.9);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-line);
  padding: 16px 24px;
}
.nav-container {
  max-width: 1140px;
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.logo {
  font-size: 1.35rem;
  font-weight: 900;
  color: #fff;
  text-decoration: none;
  display: flex;
  align-items: center;
  gap: 4px;
}
.logo span { color: var(--accent-cyan); }
.nav-links { display: flex; align-items: center; gap: 20px; }
.nav-links a {
  color: var(--text-muted);
  text-decoration: none;
  font-size: 0.95rem;
  transition: color 0.2s;
}
.nav-links a:hover, .nav-links a.active { color: var(--accent-cyan); font-weight: 500; }
.btn-nav {
  background: var(--accent-cyan);
  color: #000 !important;
  font-weight: 700 !important;
  padding: 8px 16px;
  border-radius: 6px;
  transition: opacity 0.2s;
}
.btn-nav:hover { opacity: 0.9; }

/* 容器與版型 */
.main-content { flex: 1; }
.container {
  max-width: 1140px;
  margin: 0 auto;
  padding: 60px 20px;
}
.page-header {
  text-align: center;
  padding: 70px 20px 40px;
  background: radial-gradient(circle at 50% 30%, rgba(6,182,212,0.1) 0%, transparent 70%);
}
.page-header h1 { font-size: 2.5rem; margin-bottom: 12px; font-weight: 800; }
.page-header p { color: var(--text-muted); font-size: 1.1rem; max-width: 600px; margin: 0 auto; }

/* 按鈕樣式 */
.btn-primary {
  display: inline-block;
  background: linear-gradient(135deg, var(--accent-cyan), var(--accent-blue));
  color: #fff;
  font-weight: 700;
  padding: 12px 28px;
  border-radius: 8px;
  text-decoration: none;
  box-shadow: 0 4px 15px var(--accent-glow);
  transition: transform 0.2s;
}
.btn-primary:hover { transform: translateY(-2px); }
.btn-outline {
  display: inline-block;
  border: 1px solid var(--border-line);
  color: var(--text-main);
  padding: 12px 24px;
  border-radius: 8px;
  text-decoration: none;
  transition: background 0.2s;
}
.btn-outline:hover { background: rgba(255,255,255,0.05); }

/* 卡片格點 */
.grid-3 {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 24px;
}
.card {
  background: var(--bg-surface);
  border: 1px solid var(--border-line);
  border-radius: 12px;
  padding: 30px;
  transition: transform 0.2s, border-color 0.2s;
}
.card:hover {
  transform: translateY(-4px);
  border-color: var(--accent-cyan);
}
.card-icon { font-size: 2rem; margin-bottom: 16px; }
.card h3 { font-size: 1.25rem; margin-bottom: 12px; color: #fff; }
.card p { color: var(--text-muted); font-size: 0.95rem; }

/* 頁尾 */
footer {
  border-top: 1px solid var(--border-line);
  padding: 40px 20px;
  text-align: center;
  color: var(--text-muted);
  font-size: 0.85rem;
  background: var(--bg-surface);
  margin-top: 40px;
}

@media (max-width: 768px) {
  .nav-links { gap: 12px; }
  .nav-links a { font-size: 0.85rem; }
  .page-header h1 { font-size: 2rem; }
}