/* Bootstrap CSS - 简化版本 */
.container { max-width: 1200px; margin: 0 auto; padding: 0 15px; }
.row { display: flex; flex-wrap: wrap; margin: 0 -15px; }
.col { flex: 1; padding: 0 15px; }
.btn { display: inline-block; padding: 8px 16px; margin-bottom: 0; font-size: 14px; font-weight: 400; line-height: 1.42857143; text-align: center; white-space: nowrap; vertical-align: middle; cursor: pointer; border: 1px solid transparent; border-radius: 4px; text-decoration: none; }
.btn-primary { color: #fff; background-color: #007bff; border-color: #007bff; }
.btn-primary:hover { color: #fff; background-color: #0056b3; border-color: #004085; }
.text-center { text-align: center; }
.mb-3 { margin-bottom: 1rem; }
.mt-3 { margin-top: 1rem; }
.p-3 { padding: 1rem; }
.d-none { display: none; }
.d-block { display: block; }
@media (min-width: 768px) { .d-md-block { display: block; } }
@media (max-width: 767px) { .d-md-none { display: none; } }