:root {
  --bg: #10130f;
  --surface: #f6f1e7;
  --ink: #171a15;
  --ink-soft: rgba(23, 26, 21, 0.72);
  --text: #f8f3ea;
  --muted: rgba(248, 243, 234, 0.74);
  --accent: #d8c5a2;
  --green: #31563d;
  --line: rgba(23, 26, 21, 0.14);
}

* {
  box-sizing: border-box;
}

html {
  background: var(--bg);
  scroll-behavior: smooth;
}

body {
  margin: 0;
  color: var(--ink);
  background: var(--surface);
  font-family: "Noto Sans JP", "Hiragino Sans", "Yu Gothic", "Meiryo", system-ui, sans-serif;
  letter-spacing: 0;
}

a {
  color: inherit;
  text-decoration: none;
}

img {
  max-width: 100%;
  display: block;
}

.header {
  position: sticky;
  top: 0;
  z-index: 10;
  border-bottom: 1px solid rgba(248, 243, 234, 0.12);
  background: rgba(16, 19, 15, 0.88);
  backdrop-filter: blur(18px);
  color: var(--text);
}

.header-inner {
  width: min(1120px, calc(100% - 40px));
  height: 76px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

.brand img {
  width: 168px;
  height: auto;
}

.nav {
  display: flex;
  gap: 20px;
  color: rgba(248, 243, 234, 0.78);
  font-size: 13px;
}

.nav a:hover {
  color: var(--text);
}

.article-hero {
  color: var(--text);
  background:
    linear-gradient(90deg, rgba(16, 19, 15, 0.92), rgba(16, 19, 15, 0.68)),
    url("../back.png");
  background-size: cover;
  background-position: center;
}

.hero-inner,
.footer-inner {
  width: min(1120px, calc(100% - 40px));
  margin: 0 auto;
}

.article {
  width: min(980px, calc(100% - 40px));
  margin: 0 auto;
  padding: 72px 0 92px;
}

.hero-inner {
  padding: 92px 0 76px;
}

.label {
  margin: 0 0 18px;
  color: var(--accent);
  font-size: 12px;
  font-weight: 800;
  letter-spacing: 0.18em;
  text-transform: uppercase;
}

h1 {
  max-width: 900px;
  margin: 0;
  font-family: "Noto Serif JP", "Yu Mincho", "Hiragino Mincho ProN", serif;
  font-size: clamp(32px, 4.5vw, 58px);
  line-height: 1.24;
  font-weight: 600;
  letter-spacing: 0;
}

.description {
  max-width: 760px;
  margin: 24px 0 0;
  color: var(--muted);
  font-size: 16px;
  line-height: 2;
}

.meta {
  margin-top: 28px;
  color: rgba(248, 243, 234, 0.58);
  font-size: 12px;
  letter-spacing: 0.08em;
}

.article-body {
  max-width: 760px;
}

.article-body h2 {
  margin: 54px 0 16px;
  font-family: "Noto Serif JP", "Yu Mincho", "Hiragino Mincho ProN", serif;
  font-size: 30px;
  line-height: 1.42;
  font-weight: 600;
}

.article-body h2:first-child {
  margin-top: 0;
}

.article-body h3 {
  margin: 34px 0 12px;
  color: var(--green);
  font-size: 18px;
  line-height: 1.7;
}

.article-body p {
  margin: 0 0 22px;
  color: var(--ink-soft);
  font-size: 16px;
  line-height: 2.05;
}

.article-body ul {
  margin: 0 0 28px;
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--line);
}

.article-body li {
  padding: 15px 0;
  border-bottom: 1px solid var(--line);
  color: var(--ink-soft);
  line-height: 1.85;
}

.lead-box,
.toc,
.faq {
  margin: 0 0 34px;
  padding: 24px;
  border: 1px solid var(--line);
  background: rgba(255, 255, 255, 0.34);
}

.lead-box p,
.toc p,
.faq p {
  margin-bottom: 0;
}

.toc ol {
  margin: 14px 0 0;
  padding-left: 1.3em;
  color: var(--ink-soft);
  line-height: 1.9;
}

.faq h3 {
  margin-top: 26px;
}

.faq h3:first-child {
  margin-top: 0;
}

.cta {
  margin-top: 56px;
  padding: 30px;
  border: 1px solid rgba(23, 26, 21, 0.14);
  background: rgba(255, 255, 255, 0.42);
}

.cta h2 {
  margin-top: 0;
  font-size: 26px;
}

.button {
  display: inline-flex;
  min-height: 48px;
  align-items: center;
  justify-content: center;
  border-radius: 999px;
  padding: 0 20px;
  color: #fff;
  background: var(--green);
  font-size: 14px;
  font-weight: 700;
}

.related {
  margin-top: 44px;
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.related a {
  border: 1px solid var(--line);
  padding: 9px 12px;
  color: rgba(23, 26, 21, 0.7);
  font-size: 13px;
}

.footer {
  border-top: 1px solid var(--line);
  padding: 30px 0;
  color: rgba(23, 26, 21, 0.58);
  font-size: 12px;
  line-height: 1.8;
}

.footer-inner {
  display: flex;
  justify-content: space-between;
  gap: 24px;
}

.footer p {
  margin: 0;
}

@media (max-width: 560px) {
  .header-inner,
  .hero-inner,
  .footer-inner {
    width: min(100% - 28px, 1120px);
  }

  .article {
    width: min(100% - 28px, 980px);
  }

  .brand img {
    width: 132px;
  }

  .header-inner {
    height: 66px;
  }

  .hero-inner {
    padding: 70px 0 58px;
  }

  .footer-inner {
    display: grid;
  }
}