@charset "utf-8";

:root {
    --bg: #eef3f5;
    --surface: #ffffff;
    --surface-subtle: #f4f8fa;
    --text: #182028;
    --muted: #4e5a66;
    --accent: #006d77;
    --accent-hover: #02555e;
    --border: #cdd8df;
    --max-width: 1080px;
    --radius: 14px;
    --shadow: 0 14px 38px rgba(10, 31, 44, 0.14);
}

* {
    box-sizing: border-box;
}

html,
body {
    margin: 0;
    padding: 0;
}

body,
figure {
    font-family: "Segoe UI", "Hiragino Kaku Gothic ProN", "Meiryo", sans-serif;
    color: var(--text);
    background:
        radial-gradient(circle at 0% 0%, rgba(0, 109, 119, 0.15), transparent 45%),
        radial-gradient(circle at 100% 100%, rgba(11, 105, 89, 0.12), transparent 50%),
        var(--bg);
}

a {
    color: var(--accent);
}

a:hover,
a:focus-visible {
    color: var(--accent-hover);
}

.en-label {
    font-size: 0.82em;
    color: var(--muted);
    letter-spacing: 0.02em;
    font-weight: 500;
}

header.img {
    position: relative;
    min-height: 210px;
    padding: 32px 24px;
    background:
        linear-gradient(135deg, rgba(10, 35, 46, 0.76), rgba(0, 109, 119, 0.58)),
        url("logo.jpg") center/cover;
    color: #ffffff;
}

header,
nav,
article,
aside,
section,
footer {
    display: block;
}

header h1 {
    position: absolute;
    top: 50%;
    left: 0;
    width: 100%;
    margin: 0;
    padding: 0 12px;
    color: #ffffff;
    font-size: clamp(1.9rem, 4vw, 2.8rem);
    line-height: 1.35;
    text-align: center;
    letter-spacing: 0.05em;
    transform: translateY(-50%);
}

div.nav {
    background: rgba(255, 255, 255, 0.95);
    border-bottom: 1px solid var(--border);
    margin-bottom: 12px;
}

div.nav nav {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 12px 20px;
    text-align: center;
}

div.nav ul {
    margin: 0;
    padding: 0;
}

div.nav ul li {
    list-style: none;
    display: inline-block;
    margin: 4px;
}

div.nav a {
    display: inline-block;
    text-decoration: none;
    color: var(--text);
    border: 1px solid transparent;
    border-radius: 999px;
    padding: 8px 12px;
}

div.nav a:hover,
div.nav a:focus-visible {
    background: var(--surface-subtle);
    border-color: var(--border);
}

main {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 20px;
}

div.main:after {
    content: "";
    display: block;
    clear: both;
}

div.toc {
    float: left;
    width: 24%;
    padding-right: 12px;
}

div.contents {
    float: right;
    width: 76%;
}

div.toc nav,
div.contents article,
section {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
}

div.toc nav {
    position: sticky;
    top: 12px;
    padding: 16px;
}

div.toc nav ul {
    padding-left: 1.1rem;
}

div.contents article {
    padding: 20px;
}

section {
    margin: 0 0 14px;
    padding: 16px;
}

footer {
    clear: both;
    text-align: center;
    padding: 36px 16px;
    width: 100%;
    border-top: 1px solid var(--border);
}

footer ul,
footer li {
    list-style: none;
    display: inline;
    padding: 0 10px;
}

footer .copyright small {
    color: var(--muted);
    font-size: 0.8rem;
    letter-spacing: 0.05em;
}

time[datetime] {
    color: #c4001a;
}

table {
    width: 100%;
    border-collapse: collapse;
    border: 1px solid var(--border);
    background: var(--surface);
}

table th,
table td {
    border: 1px solid var(--border);
    padding: 10px;
}

pre {
    font-family: "Consolas", "Menlo", "Monaco", monospace;
    overflow-x: auto;
    overflow-y: hidden;
    width: 100%;
    background: #13212c;
    color: #e6f1f6;
    padding: 12px;
    border-radius: 10px;
}

main h1 {
    font-size: 2rem;
}

main h2 {
    font-size: 1.6rem;
}

main h3 {
    font-size: 1.35rem;
}

main h4 {
    font-size: 1.15rem;
}

@media (max-width: 860px) {
    div.toc,
    div.contents {
        float: none;
        width: 100%;
        padding-right: 0;
    }

    div.toc nav {
        position: static;
        margin-bottom: 14px;
    }
}