:root {
    font-family: system-ui, sans-serif;
    color: #263029;
    background: #4b594a url("body.png");
    line-height: 1.55;
}
* { box-sizing: border-box; }
body { margin: 0; }
a { color: #315741; }
a:hover { color: #1d3828; }
:focus-visible { outline: 2px solid #315741; outline-offset: 3px; }
.skip-link { position: absolute; left: 1rem; top: -10rem; padding: .5rem; background: #fff; z-index: 2; }
.skip-link:focus { top: .5rem; }
#page { max-width: 86rem; margin: 0 auto; min-height: 100vh; background: #f0f1ed; }
#top { background: #fff url("top.png") no-repeat right top; padding: .3rem 1.25rem .5rem; }
#top p { margin: 0; font-size: .9rem; }
.brand { display: inline-block; }
.brand img { display: block; object-fit: contain; object-position: left; }
#navbar { background: #505b50; color: #fff; padding: .4rem 1.25rem; font-size: .9rem; }
#navbar a { color: #fff; }
.guide-layout {
    display: grid;
    grid-template-columns: clamp(14rem, 19vw, 16rem) minmax(0, 1fr) minmax(0, 21rem);
    grid-template-areas: "navigation main ads";
    align-items: start;
    gap: 1rem;
    padding: 1rem;
}
#main { grid-area: main; min-width: 0; padding: clamp(1rem, 3vw, 2rem); background: #fff; overflow-wrap: anywhere; }
h1 { margin: 0 0 1rem; line-height: 1.2; font-size: clamp(1.6rem, 3vw, 2.3rem); color: #263c2d; }
h2 { line-height: 1.3; }
#main img { display: block; max-width: 100%; height: auto; }
.section-link, .archive-note, .article-date { font-size: .9rem; }
.archive-note { background: #f4f4ed; border-left: 3px solid #77764a; padding: .6rem .8rem; }
.example { background: #f1f3ee; border-left: 3px solid #758779; padding: .1rem 1rem; }
.article-date { color: #45544a; }
#navigation {
    grid-area: navigation;
    font-family: "Inter", "Segoe UI", system-ui, sans-serif;
    color: #293a30;
}
#navigation nav {
    display: grid;
    gap: .9rem;
}
#navigation section {
    background: #fafbf8;
    border: 1px solid #d9e1d8;
    border-radius: 14px;
    box-shadow: 0 2px 6px #263c2d0b;
}
#navigation h2 {
    margin: 0;
    font-size: 1rem;
    line-height: 1.35;
}
#navigation h2 a {
    display: grid;
    grid-template-columns: 1fr auto;
    align-items: center;
    gap: .65rem;
    min-height: 48px;
    padding: .75rem .85rem;
    border-radius: 13px 13px 0 0;
    border-bottom: 1px solid #dce5db;
    background: #eaf0e8;
    color: #203c2c;
    font-weight: 700;
    text-decoration: none;
}
#navigation h2 a::after {
    content: "";
    width: .4rem;
    height: .4rem;
    border: solid currentColor;
    border-width: 1.5px 1.5px 0 0;
    transform: rotate(45deg);
}
#navigation ul {
    margin: 0;
    padding: .4rem .35rem;
    list-style: none;
}
#navigation li + li {
    margin-top: .1rem;
}
#navigation li a {
    position: relative;
    display: flex;
    align-items: center;
    min-height: 42px;
    padding: .5rem .55rem;
    border-radius: 8px;
    color: #293e30;
    font-size: .94rem;
    font-weight: 500;
    line-height: 1.4;
    text-decoration: none;
}
#navigation .subtopic a {
    padding-left: 1.55rem;
}
#navigation .subtopic a::before {
    content: "";
    position: absolute;
    left: .65rem;
    width: .4rem;
    height: .4rem;
    border-left: 1px solid #5a7361;
    border-bottom: 1px solid #5a7361;
}
#navigation a:hover {
    background: #e4ece2;
    color: #203c2c;
    text-decoration: underline;
    text-underline-offset: .16em;
}
#navigation a:focus-visible {
    outline-offset: -3px;
    text-decoration: underline;
}
#navigation a[aria-current="page"] {
    background: #d6e6d7;
    color: #183924;
    font-weight: 700;
    box-shadow: inset 3px 0 #39734f;
}

.ad-column { grid-area: ads; min-width: 0; }
.ad-slot { text-align: center; color: #45544a; font-size: .8rem; }
.ad-square { min-height: 19rem; }
.ad-banner { max-width: 46rem; margin: 0 auto 1rem; min-height: 7rem; }
.adsbygoogle { display: block; min-width: 0; }
footer { display: flex; flex-wrap: wrap; gap: .4rem 1rem; padding: 1rem 1.25rem; border-top: 1px solid #c8cec5; font-size: .9rem; }
@media (max-width: 69rem) {
    .guide-layout { grid-template-columns: 14rem minmax(0, 1fr); grid-template-areas: "navigation main" "navigation ads"; }
}
@media (max-width: 42rem) {
    .guide-layout { grid-template-columns: minmax(0, 1fr); grid-template-areas: "main" "navigation" "ads"; padding: .6rem; }
    #top { background-image: none; }
}