#paste-area {
    height: 250px;
    border: 2px dashed #cbd5e1;
    transition: all 0.2s;
    overflow-y: auto;
}
#paste-area:focus {
    border-color: #3b82f6;
    outline: none;
    background-color: #f8fafc;
}
#paste-area table {
    border-collapse: collapse;
    width: auto !important;
    margin: 0;
}
#paste-area td, #paste-area th {
    border: 1px solid #ddd;
    padding: 2px;
    min-width: 10px;
}
.preview-container table {
    border-collapse: collapse;
    margin: auto;
    min-width: max-content;/**/
    /*width: 100%;                 追加 */
    max-width: 100%;            /* 追加 */
}
#output-code {
    white-space: pre;
    overflow-x: auto;
}
.switch {
    position: relative;
    display: inline-block;
    width: 40px;
    height: 20px;
}
.switch input { display: none; }
.slider {
    position: absolute;
    cursor: pointer;
    top: 0; left: 0; right: 0; bottom: 0;
    background-color: #ccc;
    transition: .4s;
    border-radius: 20px;
}
.slider:before {
    position: absolute;
    content: "";
    height: 14px; width: 14px;
    left: 3px; bottom: 3px;
    background-color: white;
    transition: .4s;
    border-radius: 50%;
}
input:checked + .slider { background-color: #3b82f6; }
input:checked + .slider:before { transform: translateX(20px); }