.venn-wrap { padding: 1rem 0; font-family: teX;}
.venn-svg  { display: block; margin: 0 auto; }

.btn-row { display: flex; flex-wrap: wrap; gap: 8px; justify-content: center; margin: 1rem 0 0.5rem; }

button.vbtn {
    font-family:teX;  
    background: transparent; border: 0.5px solid #BFA9FF; border-radius: 8px;
    padding: 6px 16px; font-size: 90%; 
    cursor: pointer; color: #FFF; transition: background 0.15s;
}

button.vbtn:hover, button.vbtn.active { background: #CCC; border-color: #7F77DD; }

.result-line { text-align: center; font-size: 100%; color: #FFF; margin: 0.5rem 0 0.25rem; min-height: 1.6em; }
.ext-wrap { text-align: center; margin-bottom: 0.5rem; min-height: 2em; }
.extension-line {
  display: inline-block; font-family: teX; font-size: 100%;
  color: #F44; background: #CCC; border: 0.5px solid #AFA9EC;
  border-radius: 6px; padding: 4px 12px;
}
.extension-line:empty { background: transparent; border-color: transparent; }