:root {
  --surface: #fcfcfb;
  --surface-2: #f2f1ee;
  --ink: #0b0b0b;
  --ink-secondary: #52514e;
  --ink-muted: #898781;
  --border: #e1e0d9;
  --accent: #2a78d6;
  --good: #0ca30c;
  --warning: #eda100;
  --critical: #d03b3b;
  --radius: 14px;
  color-scheme: light dark;
}

@media (prefers-color-scheme: dark) {
  :root {
    --surface: #1a1a19;
    --surface-2: #232322;
    --ink: #ffffff;
    --ink-secondary: #c3c2b7;
    --ink-muted: #898781;
    --border: #383835;
    --accent: #3987e5;
    --good: #0ca30c;
    --warning: #c98500;
    --critical: #e66767;
  }
}

* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  padding: 0;
  background: var(--surface-2);
  color: var(--ink);
  font-family: system-ui, -apple-system, "Hiragino Sans", "Yu Gothic", "Noto Sans JP", sans-serif;
  overflow-x: hidden;
  line-height: 1.75;
}

a {
  color: var(--accent);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

img {
  max-width: 100%;
}

/* ---------- レイアウト全体 ---------- */

.site-header {
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 10;
}

.site-header-inner {
  max-width: 880px;
  margin: 0 auto;
  padding: 14px 16px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  flex-wrap: wrap;
}

.site-logo {
  font-size: 17px;
  font-weight: 700;
  color: var(--ink);
}

.site-logo:hover {
  text-decoration: none;
  opacity: 0.8;
}

.site-nav {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
  font-size: 13.5px;
}

.site-nav a {
  color: var(--ink-secondary);
}

main {
  max-width: 880px;
  margin: 0 auto;
  padding: 32px 16px 64px;
}

.site-footer {
  background: var(--surface);
  border-top: 1px solid var(--border);
  margin-top: 40px;
}

.site-footer-inner {
  max-width: 880px;
  margin: 0 auto;
  padding: 24px 16px 40px;
  color: var(--ink-muted);
  font-size: 13px;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.site-footer-inner nav {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
}

.site-footer-inner nav a {
  color: var(--ink-secondary);
}

/* ---------- トップページ ---------- */

.hero {
  padding: 12px 0 8px;
}

.hero h1 {
  font-size: 26px;
  margin: 0 0 10px;
}

.hero p {
  color: var(--ink-secondary);
  font-size: 15px;
  max-width: 60ch;
}

section {
  margin-top: 40px;
}

section > h2 {
  font-size: 18px;
  margin: 0 0 14px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--border);
}

.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  gap: 14px;
}

.tool-card,
.article-card {
  display: block;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 18px;
  color: var(--ink);
}

.tool-card:hover,
.article-card:hover {
  border-color: var(--accent);
  text-decoration: none;
}

.tool-card h3,
.article-card h3 {
  margin: 0 0 6px;
  font-size: 16px;
}

.tool-card p,
.article-card p {
  margin: 0;
  color: var(--ink-secondary);
  font-size: 13.5px;
  line-height: 1.7;
}

.tool-card .tool-link {
  display: inline-block;
  margin-top: 10px;
  font-size: 13px;
  color: var(--accent);
}

.article-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.article-list a {
  display: block;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 14px 16px;
  color: var(--ink);
}

.article-list a:hover {
  border-color: var(--accent);
  text-decoration: none;
}

.article-list .a-title {
  font-weight: 600;
  font-size: 15px;
}

.article-list .a-desc {
  color: var(--ink-secondary);
  font-size: 13px;
  margin-top: 4px;
}

/* ---------- 記事ページ／プライバシー／運営者情報 ---------- */

.prose {
  max-width: 700px;
}

.prose h1 {
  font-size: 24px;
  margin: 0 0 6px;
}

.prose .lede {
  color: var(--ink-secondary);
  font-size: 14px;
  margin: 0 0 28px;
}

.prose h2 {
  font-size: 18px;
  margin: 32px 0 12px;
}

.prose h3 {
  font-size: 15.5px;
  margin: 22px 0 10px;
}

.prose p {
  margin: 0 0 16px;
  font-size: 15px;
  color: var(--ink);
}

.prose ul,
.prose ol {
  margin: 0 0 16px;
  padding-left: 22px;
  font-size: 15px;
}

.prose li {
  margin-bottom: 6px;
}

.prose table {
  width: 100%;
  border-collapse: collapse;
  margin: 0 0 20px;
  font-size: 13.5px;
  display: block;
  overflow-x: auto;
}

.prose th,
.prose td {
  border: 1px solid var(--border);
  padding: 8px 10px;
  text-align: left;
  white-space: nowrap;
}

.prose th {
  background: var(--surface-2);
}

.note-box {
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 14px 16px;
  font-size: 13.5px;
  color: var(--ink-secondary);
  margin: 0 0 20px;
}

.fill-me {
  background: color-mix(in srgb, var(--warning) 18%, var(--surface));
  border: 1px dashed var(--warning);
  border-radius: 8px;
  padding: 1px 6px;
  color: var(--ink);
  font-weight: 600;
}

.breadcrumb {
  font-size: 13px;
  color: var(--ink-muted);
  margin: 0 0 18px;
}

.breadcrumb a {
  color: var(--ink-muted);
}

.article-nav {
  margin-top: 40px;
  padding-top: 20px;
  border-top: 1px solid var(--border);
  font-size: 13.5px;
}

/* ---------- 404 ---------- */

.not-found {
  text-align: center;
  padding: 60px 16px;
}

.not-found h1 {
  font-size: 22px;
}

.not-found p {
  color: var(--ink-secondary);
}