.articles-source-button{
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    margin-bottom: 60px;
}
.articles-source-button li a{
    width: 23vw;
    margin-top: 0;
}
.articles-source-button li a::after{
    top: calc(50% - 8px);
    transform: rotate(135deg);
}

.articles-source{
    margin-top: 60px;
}

@media screen and (max-width: 1280px){
    .articles-source{
        margin-top: 50px;
    }
}

@media screen and (max-width: 768px){
    .articles-source-button li a{
        width: 46.5vw;
    }
}