.codebox {
    position: relative;
    margin-bottom:30px;
    max-width:500px;
}

.fname{
    background-color:#272822;
    color:white;
    width:120px;
    text-align: center;
    border-radius: 5px 5px 0px 0px;
}

pre {
    border-radius: 0px 8px 8px 8px !important; 
    margin-top:0px !important;
}

.copy-button {
    position: absolute;
    top: 30px;
    right: 8px;
    display: flex;
    align-items: center;
    gap: 6px;
    /* background: rgba(255,255,255,0.1); */
    border: 1px solid #ccc;
    border-radius: 6px;
    padding: 4px 10px;
    cursor: pointer;
    transition: background 0.2s;
    color: white;
}

.copy-button:hover {
  background: rgba(255, 255, 255, 0.2);
}

.copy-icon {
  width: 18px;
  height: 18px;
  vertical-align: middle;
}

.copy-text {
  font-size: 0.8em;
  color: white;
  opacity: 0;
  transition: opacity 0.3s;
}

.copy-button.copied .copy-text {
  opacity: 1;
}

.copy-button img {
  width: 20px;
  height: 20px;
  filter: invert(80%); /* 暗い背景でも白っぽく見える */
  transition: filter 0.2s;
}