Fix error css on validator

My site have 2 error.

1. The @charset rule may only occur at the start of the style sheet. Please check that there are no spaces before it.?@charset “UTF-8”;
2. .uagb-block-fc2d2e00.wp-block-uagb-advanced-heading .uagb-highlightValue Error : font-weight?Default?is not a?font-weight?value :?Default

https://jigsaw.w3.org/css-validator/validator?uri=https%3A%2F%2Fthuthiemhomes.com%2F&profile=css3svg&usermedium=all&warning=1&vextwarning=&lang=en

Can you guys help me and fix it.

Thank you so much!