* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

:root {
  --bg-primary: #ffffff;
  --bg-secondary: #f8f9fa;
  --text-primary: #1a1a1a;
  --text-secondary: #6c757d;
  --border-color: #dee2e6;
  --accent-color: #0066cc;
  --accent-hover: #0052a3;
  --success-color: #28a745;
  --danger-color: #dc3545;
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.06);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.08);
  --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.12);
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Noto Sans TC', sans-serif;
  background: var(--bg-secondary);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 2rem 1rem;
}

header {
  text-align: center;
  margin-bottom: 3rem;
}

h1 {
  font-size: 2.5rem;
  font-weight: 600;
  margin-bottom: 0.5rem;
  color: var(--text-primary);
}

h2 {
  font-size: 1.5rem;
  font-weight: 500;
  margin-bottom: 1rem;
}

p {
  color: var(--text-secondary);
  font-size: 1rem;
}

.apps-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1.5rem;
  margin-top: 2rem;
}

.app-card {
  background: var(--bg-primary);
  border-radius: 12px;
  padding: 2rem;
  text-decoration: none;
  color: var(--text-primary);
  transition: all 0.2s ease;
  border: 1px solid var(--border-color);
  box-shadow: var(--shadow-sm);
}

.app-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
  border-color: var(--accent-color);
}

.app-icon {
  font-size: 3rem;
  margin-bottom: 1rem;
  display: block;
}

.app-card h2 {
  margin-bottom: 0.5rem;
}

.app-card p {
  font-size: 0.9rem;
}

button {
  background: var(--accent-color);
  color: white;
  border: none;
  padding: 0.75rem 1.5rem;
  border-radius: 8px;
  font-size: 1rem;
  cursor: pointer;
  transition: background 0.2s ease;
  font-family: inherit;
}

button:hover {
  background: var(--accent-hover);
}

button:disabled {
  background: var(--text-secondary);
  cursor: not-allowed;
}

button.secondary {
  background: var(--bg-secondary);
  color: var(--text-primary);
  border: 1px solid var(--border-color);
}

button.secondary:hover {
  background: var(--border-color);
}

button.danger {
  background: var(--danger-color);
}

button.danger:hover {
  background: #c82333;
}

input[type="text"],
input[type="number"],
select {
  width: 100%;
  padding: 0.75rem;
  border: 1px solid var(--border-color);
  border-radius: 8px;
  font-size: 1rem;
  font-family: inherit;
  background: var(--bg-primary);
  transition: border-color 0.2s ease;
}

input:focus,
select:focus {
  outline: none;
  border-color: var(--accent-color);
}

.back-link {
  display: inline-block;
  margin-bottom: 2rem;
  color: var(--accent-color);
  text-decoration: none;
  font-size: 0.9rem;
}

.back-link:hover {
  text-decoration: underline;
}

@media (max-width: 768px) {
  .container {
    padding: 1rem;
  }

  h1 {
    font-size: 2rem;
  }

  .apps-grid {
    grid-template-columns: 1fr;
  }
}