/* ===== 按钮 ===== */
.btn {
    padding: 10px 20px;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    font-size: 14px;
    font-weight: 500;
    transition: all 0.2s;
}
.btn-primary {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
}
.btn-primary:hover {
    transform: translateY(-1px);
    box-shadow: 0 4px 12px rgba(102, 126, 234, 0.3);
}
.btn-primary:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    transform: none;
    box-shadow: none;
}
.btn-secondary {
    background: #f0f0f0;
    color: #555;
}
.btn-secondary:hover { background: #e0e0e0; }
.btn-success { background: #28a745; color: white; }
.btn-success:hover { background: #218838; }
.btn-danger  { background: #dc3545; color: white; }
.btn-danger:hover  { background: #c82333; }
.btn-sm { padding: 6px 12px; font-size: 12px; }