narrow {
    margin: 0;
    padding: 0;
}

body {
    font-family: 'Helvetica Neue', Arial, sans-serif;
    line-height: 1.6;
    color: #ffffff;
    max-width: 1000px;
    margin: 0 auto;
    padding: 20px;
    background-color: #f9f9f9;
}

header {
    background-color: #2c3e50;
    color: #ffffff;
    padding: 20px;
    border-radius: 5px;
    margin-bottom: 30px;
}

h1 {
    color: #ecf0f1;
    text-align: center;
    margin: 0;
}

.since {
    color: rgb(0, 0, 0);
    display: block;
    font-size: 0.8em;
    text-align: left;
    margin-top: 1em;
}

main {
    background-color: #ffffff;
    color: #333333;
    padding: 30px;
    border-radius: 5px;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}

h2 {
    background-color: #3498db;
    color: #ffffff;
    padding: 10px;
    border-radius: 5px;
    margin-top: 30px;
}

h3 {
    background: #2980b9;
    color: #ffffff;
    padding: 8px;
    border-radius: 5px;
    margin-top: 20px;
}

p {
    margin-bottom: 15px;
}

li {
    list-style-type: none;
    margin-bottom: 10px;
}

li.file::before,
li.outerlink::before,
li.link::before {
    margin-right: 10px;
    vertical-align: middle;
}

main a {
    color: #2980b9;
    text-decoration: none;
    padding: 8px 15px;
    background-color: #ecf0f1;
    border-radius: 5px;
    transition: all 0.3s ease;
    display: inline-block;
    margin: 5px 0;
}

main a:hover {
    background-color: #3498db;
    color: #ffffff;
}

.history {
    background-color: #f2f2f2;
    padding: 15px;
    border-radius: 5px;
    margin-top: 20px;
}

footer {
    margin-top: 30px;
    text-align: center;
}

.gotop {
    display: inline-block;
    color: #ffffff;
    padding: 10px 15px;
    border-radius: 5px;
    text-decoration: none;
    transition: background-color 0.3s ease;
}

.gotop {
    display: none;
    position: fixed;
    bottom: 2rem;
    right: 1rem;
}

.gotop a{
    padding: 0;
    margin: 0;
    border: 0;
    text-decoration: none;
    background-image: url('/icon/gotop.svg');
    color: white;
    background-color:#34495e;
    width: 2em;
    height: 2em;
    border-radius: 50%;
    opacity: 1.0;
    animation: buttonflow 3s 1;
    display: block;
}

@media (max-width: 768px) {
    body {
        padding: 10px;
    }

    main {
        padding: 15px;
    }

    h1 {
        font-size: 24px;
    }

    h2 {
        font-size: 20px;
    }

    h3 {
        font-size: 18px;
    }

    main a {
        display: block;
        text-align: center;
    }
}



li.file::before {
    content: "\1f4be";
    font-size: 2rem;
    position: relative; /* 追加 */
}

li.outerlink::before {
    content: "\1F517";
    font-size: 2rem;
    position: relative; /* 追加 */

}

li.link::before {
    content: "\1F4DC";
    font-size: 2rem;
    position: relative; /* 追加 */
}

.back {
    outline: none;
    padding-bottom: 2px;
    border-right:  1px solid #d8daff;
    border-bottom: 1px solid #d8daff;
    margin: 0.2em;
    font-size: 1.6em;
    height: 1.6em;
    line-height: 1.6em;
    width: 3em; 
    border-radius: 0.2em;
    text-decoration: none;
    display: inline-block;
    text-align: center;
    color: #60c0ff;
    background-color: #d5ecff;
}


.back:hover {
    color: #d5ecff;
    background-color:#60c0ff;
}

.button {
    padding: 0.1em;
    margin: 0.1em;
    border-radius: 0.5em;
    border: 0.1em;
    line-height: 2rem;
    font-size: 2rem;
}

.button2 {
    border-right:  1px solid #d8daff;
    border-bottom: 1px solid #d8daff;
    color: #60c0ff;
    background-color: #d5ecff;
    padding: 0.2em;
    height: 1.0em;
    margin: 0.2em;
    width: 3em;
    border-radius: 0.2em;
    line-height: 1.0em;
    font-size: 1.6rem;
    text-align: center;
}

textarea {
    background-color: #f2f2f2;
    border-radius: 5px;
    font-size: 1.2em;
}

input {
    background-color: #f2f2f2;
    border-radius: 5px;
    font-size: 1.2em;
    text-align: right;
}


summary {
    display: inline-block;
    border-right:  1px solid #d8daff;
    border-bottom: 1px solid #d8daff;
    background-color:#60c0ff;
    color: #fbfcff;
    padding: 0.5rem;
    border-radius: 5px;
}

summary:hover{
    border-color: transparent;
    box-shadow: 0 2px 6px rgba(0, 0, 0, 0.5);
}

details {
    color: #333333;
    text-align: left;
}

@keyframes buttonflow {
    from { opacity: 0; }
    to { opacity: 100; }
}

.gotop a:hover {
    opacity: 0.60;
    color: grey;
}