:root {
  --bg: #0f172a;
  --bg2: #1e293b;
  --fg: #1f2933;
  --muted: #64748b;
  --line: #e2e8f0;
  --accent: #2563eb;
  --accent2: #0ea5e9;
  --card: #ffffff;
  --ok: #16a34a;
  --err: #dc2626;
  --maxw: 980px;
}

* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  font-family: system-ui, -apple-system, "Segoe UI", "Hiragino Kaku Gothic ProN", "Noto Sans CJK SC", "Microsoft YaHei", Meiryo, sans-serif;
  color: var(--fg);
  background: #f8fafc;
  line-height: 1.7;
}
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }
.wrap { max-width: var(--maxw); margin: 0 auto; padding: 0 16px; }
.wrap-wide { max-width: 1200px; }
.mono { font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace; }
.small { font-size: .85rem; }

/* Header */
.site-header {
  background: linear-gradient(120deg, var(--bg), var(--bg2));
  color: #fff;
  position: sticky; top: 0; z-index: 50;
  box-shadow: 0 1px 6px rgba(0,0,0,.15);
}
.site-header .wrap { display: flex; align-items: center; gap: 16px; min-height: 56px; flex-wrap: wrap; }
.brand { color: #fff; font-weight: 700; font-size: 1.05rem; white-space: nowrap; }
.brand:hover { text-decoration: none; }
.brand-mark {
  display: inline-block; background: var(--accent2); color: #04293b;
  border-radius: 6px; padding: 1px 7px; font-weight: 800; margin-right: 4px;
}
.site-nav { display: flex; align-items: center; gap: 14px; margin-left: auto; flex-wrap: wrap; }
.site-nav a { color: #cbd5e1; font-size: .92rem; }
.site-nav a:hover, .site-nav a.active { color: #fff; text-decoration: none; }
.site-nav a.active { border-bottom: 2px solid var(--accent2); }
.lang-switch { display: inline-flex; gap: 8px; margin-left: 6px; padding-left: 12px; border-left: 1px solid #475569; font-size: .85rem; }
.lang-switch strong { color: #fff; }
.lang-switch a { color: #94a3b8; }
.nav-toggle { display: none; background: none; border: 0; color: #fff; font-size: 1.4rem; cursor: pointer; margin-left: auto; }

@media (max-width: 760px) {
  .nav-toggle { display: block; }
  .site-nav { display: none; width: 100%; flex-direction: column; align-items: flex-start; gap: 10px; padding: 8px 0; }
  .site-nav.open { display: flex; }
  .lang-switch { border-left: 0; padding-left: 0; margin-left: 0; }
}

/* Main */
main.wrap { padding-top: 24px; padding-bottom: 48px; }
.breadcrumb { font-size: .82rem; color: var(--muted); margin-bottom: 16px; }
.breadcrumb a { color: var(--muted); }
h1 { font-size: 1.7rem; line-height: 1.3; margin: .2em 0 .5em; }
h2 { font-size: 1.3rem; margin-top: 1.6em; border-left: 4px solid var(--accent2); padding-left: 10px; }
h3 { font-size: 1.08rem; }
.lead { color: var(--muted); font-size: 1.02rem; margin-top: 0; }
.note { color: var(--muted); font-size: .85rem; background: #f1f5f9; border-radius: 8px; padding: 8px 12px; }

/* Hero (self IP) */
.hero { text-align: center; }
.hero-lead { color: var(--muted); }
.ip-card {
  display: inline-flex; align-items: center; gap: 14px;
  background: linear-gradient(120deg, var(--bg), var(--bg2));
  color: #fff; border-radius: 14px; padding: 18px 26px; margin: 8px 0 18px;
  box-shadow: 0 6px 20px rgba(15,23,42,.25);
}
.ip-big { font-family: ui-monospace, monospace; font-size: clamp(1.4rem, 5vw, 2.4rem); font-weight: 700; letter-spacing: .5px; word-break: break-all; }
.copy-btn { background: var(--accent2); color: #04293b; border: 0; border-radius: 8px; padding: 6px 12px; font-weight: 700; cursor: pointer; }

/* key/value table */
.kv { width: 100%; border-collapse: collapse; margin: 8px 0 16px; background: var(--card); border-radius: 10px; overflow: hidden; box-shadow: 0 1px 4px rgba(0,0,0,.06); }
.kv th, .kv td { text-align: left; padding: 9px 14px; border-bottom: 1px solid var(--line); vertical-align: top; }
.kv th { width: 38%; background: #f1f5f9; color: #334155; font-weight: 600; font-size: .9rem; }
.kv td { word-break: break-word; }
.hero .kv { text-align: left; max-width: 640px; margin-left: auto; margin-right: auto; }

/* Tool cards */
.tools-grid h2, .article-hubs h2 { text-align: left; }
.cards { display: grid; grid-template-columns: repeat(auto-fill, minmax(260px, 1fr)); gap: 14px; }
.card { display: flex; flex-direction: column; gap: 4px; background: var(--card); border: 1px solid var(--line); border-radius: 12px; padding: 16px; color: var(--fg); transition: transform .08s, box-shadow .08s; }
.card:hover { text-decoration: none; transform: translateY(-2px); box-shadow: 0 6px 18px rgba(0,0,0,.08); }
.card-ic { font-size: 1.5rem; }
.card strong { color: var(--accent); }
.card span:last-child { color: var(--muted); font-size: .85rem; }

/* Tool forms */
.tool-form { display: flex; gap: 8px; margin: 14px 0; flex-wrap: wrap; }
.tool-form input { flex: 1 1 260px; padding: 11px 14px; border: 1px solid #cbd5e1; border-radius: 10px; font-size: 1rem; }
.tool-form input:focus { outline: 2px solid var(--accent2); border-color: var(--accent2); }
.tool-form button { background: var(--accent); color: #fff; border: 0; border-radius: 10px; padding: 0 22px; font-weight: 700; cursor: pointer; font-size: 1rem; }
.tool-form button:hover { background: #1d4ed8; }
.tool-result { min-height: 1em; }
.loading { color: var(--muted); }
.err { color: var(--err); }

/* Article hubs / lists */
.article-hubs { margin-top: 8px; }
.hub { margin-bottom: 22px; }
.hub-desc { color: var(--muted); font-size: .9rem; margin: 2px 0 6px; }
.article-list { margin: 0; padding-left: 18px; }
.article-list li { margin: 4px 0; }
.article-list.big { list-style: none; padding: 0; }
.article-list.big li { padding: 12px 0; border-bottom: 1px solid var(--line); }
.article-list.big a { font-weight: 600; font-size: 1.05rem; }
.article-list.big .desc { display: block; color: var(--muted); font-size: .88rem; }

/* Prose (articles) */
.prose { background: var(--card); border-radius: 12px; padding: 8px 28px 24px; box-shadow: 0 1px 4px rgba(0,0,0,.05); }
.prose .meta { color: var(--muted); font-size: .82rem; }
.prose p, .prose li { font-size: 1rem; }
.prose pre { background: #0f172a; color: #e2e8f0; padding: 14px 16px; border-radius: 10px; overflow-x: auto; font-size: .88rem; }
.prose code { font-family: ui-monospace, monospace; background: #f1f5f9; padding: 1px 5px; border-radius: 4px; font-size: .9em; }
.prose pre code { background: none; padding: 0; color: inherit; }
.prose table { border-collapse: collapse; width: 100%; margin: 12px 0; font-size: .92rem; display: block; overflow-x: auto; }
.prose th, .prose td { border: 1px solid var(--line); padding: 7px 10px; text-align: left; }
.prose th { background: #f1f5f9; }
.prose blockquote { border-left: 4px solid var(--accent2); margin: 12px 0; padding: 2px 14px; color: #475569; background: #f8fafc; }
.sources, .related { margin-top: 24px; padding-top: 8px; border-top: 1px solid var(--line); }
.sources ul, .related ul { font-size: .92rem; }

/* Glossary */
.glossary dt { font-weight: 700; margin-top: 16px; }
.glossary dt .reading { font-weight: 400; color: var(--muted); font-size: .85rem; }
.glossary dd { margin: 4px 0 0; color: #334155; }

.ok { color: var(--ok); }

/* Status badges (SSL / headers / dnssec / rpki results) */
.badge { display: inline-block; padding: 1px 9px; border-radius: 999px; font-size: .8rem; font-weight: 700; line-height: 1.5; white-space: nowrap; }
.badge-pass { background: #dcfce7; color: #166534; }
.badge-warn { background: #fef9c3; color: #854d0e; }
.badge-fail { background: #fee2e2; color: #991b1b; }
.kv.checks td code { background: #f1f5f9; padding: 1px 5px; border-radius: 4px; font-size: .85em; word-break: break-all; }
.kv.checks .small { color: var(--muted); }

/* SSL sales call-to-action */
.ssl-cta { background: #ecfeff; border: 1px solid #a5f3fc; border-radius: 10px; padding: 10px 14px; font-size: .92rem; margin: 4px 0 18px; }

/* CIDR tool blocks + command generator */
.cidr-block { margin: 18px 0; padding-top: 6px; border-top: 1px solid var(--line); }
.cidr-block h2 { margin-top: .4em; }
.cidr-list { list-style: none; padding: 0; margin: 6px 0; columns: 2; column-gap: 16px; }
.cidr-list li { padding: 2px 0; break-inside: avoid; }
.cmd-row { display: flex; align-items: center; gap: 8px; margin: 6px 0; flex-wrap: wrap; }
.cmd-os { flex: 0 0 96px; color: var(--muted); font-size: .82rem; font-weight: 600; }
.cmd-line { flex: 1 1 280px; background: #0f172a; color: #e2e8f0; padding: 8px 12px; border-radius: 8px; font-family: ui-monospace, monospace; font-size: .85rem; overflow-x: auto; white-space: pre; }
.cmd-row .copy-btn { padding: 6px 10px; }
@media (max-width: 560px) { .cidr-list { columns: 1; } }

/* Tool guide (FAQ/HowTo prose under each tool) */
.tool-guide { margin-top: 30px; padding: 8px 28px 20px; background: var(--card); border-radius: 12px; box-shadow: 0 1px 4px rgba(0,0,0,.05); }
.tool-guide h2 { font-size: 1.2rem; }
.tool-guide pre { background: #0f172a; color: #e2e8f0; padding: 14px 16px; border-radius: 10px; overflow-x: auto; font-size: .86rem; }
.tool-guide code { font-family: ui-monospace, monospace; background: #f1f5f9; padding: 1px 5px; border-radius: 4px; font-size: .9em; }
.tool-guide pre code { background: none; padding: 0; color: inherit; }
.tool-guide table { border-collapse: collapse; width: 100%; margin: 12px 0; font-size: .92rem; display: block; overflow-x: auto; }
.tool-guide th, .tool-guide td { border: 1px solid var(--line); padding: 7px 10px; text-align: left; }
.tool-guide th { background: #f1f5f9; }
.tool-guide blockquote { border-left: 4px solid var(--accent2); margin: 12px 0; padding: 2px 14px; color: #475569; background: #f8fafc; }

/* FAQ (details/summary) */
.faq { margin-top: 18px; }
.faq details { border: 1px solid var(--line); border-radius: 8px; padding: 8px 14px; margin: 8px 0; background: #fff; }
.faq summary { cursor: pointer; font-weight: 600; }
.faq details[open] summary { margin-bottom: 6px; }
.faq p { margin: 0; color: #334155; }

/* Ad unit */
.ad-unit { margin: 28px 0 0; min-height: 1px; text-align: center; }

/* Footer */
.site-footer { background: #0f172a; color: #94a3b8; padding: 26px 0; font-size: .85rem; margin-top: 40px; }
.site-footer a { color: #cbd5e1; }
.site-footer .ssl-promo { margin: 0 0 8px; }
.site-footer .disclaimer { font-size: .78rem; color: #64748b; }
.site-footer .copy { margin-top: 10px; color: #64748b; }