/* Reset & Base */
* { margin: 0; padding: 0; box-sizing: border-box; }
body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  background: #f5f7fa;
  color: #333;
  line-height: 1.6;
  min-height: 100vh;
}

/* Links */
a { color: #667eea; text-decoration: none; transition: color 0.3s; }
a:hover { color: #764ba2; }

/* Buttons */
.btn {
  display: inline-block;
  padding: 0.8rem 1.5rem;
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  color: white;
  border-radius: 6px;
  text-decoration: none;
  transition: transform 0.3s, box-shadow 0.3s;
  border: none;
  cursor: pointer;
}
.btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(102, 126, 234, 0.4);
}

/* Responsive Images */
img { max-width: 100%; height: auto; }

/* Utility Classes */
.container { max-width: 1200px; margin: 0 auto; padding: 0 1rem; }
.text-center { text-align: center; }
.mt-1 { margin-top: 1rem; }
.mt-2 { margin-top: 2rem; }
.mb-1 { margin-bottom: 1rem; }
.mb-2 { margin-bottom: 2rem; }

/* Responsive */
@media (max-width: 768px) {
  body { font-size: 0.95rem; }
  h1 { font-size: 1.5rem !important; }
  h2 { font-size: 1.3rem !important; }
  h3 { font-size: 1.1rem !important; }
}

/* Animations */
@keyframes fadeIn {
  from { opacity: 0; transform: translateY(20px); }
  to { opacity: 1; transform: translateY(0); }
}

.fade-in { animation: fadeIn 0.6s ease-out; }