.iframe-wrap iframe {
  display: none;
  width: 100%;
  height: 550px;
  border: none;
}

.iframe-wrap .f3 { display: block; }

#t1:checked ~ .iframe-wrap .f1 { display: block; }
#t2:checked ~ .iframe-wrap .f2 { display: block; }
#t3:checked ~ .iframe-wrap .f3 { display: block; }
    

.tab-buttons {
  display: flex;
  width: fit-content;
  border: 1px solid #ddd;
}

.tab-buttons input {
  display: none;
}

.tab-buttons label {
  padding: 10px 24px;
  background: #e0e0e0;
  color: #000;
  font-weight: 600;
  cursor: pointer;
  border-right: 1px solid #fff;
  font-family: "Helvetica Neue", Helvetica, Arial, sans-serif;
}

.tab-buttons label:last-child {
  border-right: none;
}

/* nút đang được chọn */
.tab-buttons input:checked + label {
  background: #0b4fa2;
  color: #fff;
}