/* BRAND CRAFT AI — Articles */
:root {
  --bg: #ffffff;
  --ink: #09090b;
  --text: #27272a;
  --muted: #71717a;
  --line: #e4e4e7;
  --soft: #f4f4f5;
  --panel: #1c1c1e;
  --wrap: 960px;
  --read: 680px;
  --font: "DM Sans", "Hiragino Sans", "Hiragino Kaku Gothic ProN", "Noto Sans JP", "Yu Gothic", sans-serif;
}
*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0; background: var(--bg); color: var(--text);
  font-family: var(--font); font-size: 16px; line-height: 1.9;
  -webkit-font-smoothing: antialiased;
}
a { color: inherit; }
img { max-width: 100%; height: auto; display: block; }
:focus-visible { outline: 2px solid var(--ink); outline-offset: 3px; border-radius: 4px; }
.wrap { max-width: var(--wrap); margin: 0 auto; padding: 0 24px; }

/* Header */
.site-header {
  position: sticky; top: 0; z-index: 10; background: rgba(255,255,255,.92);
  backdrop-filter: saturate(180%) blur(12px); -webkit-backdrop-filter: saturate(180%) blur(12px);
  border-bottom: 1px solid var(--line);
}
.site-header .wrap { display: flex; align-items: center; justify-content: space-between; height: 72px; }
.logo { font-weight: 600; font-size: 20px; letter-spacing: .01em; color: var(--ink); text-decoration: none; }
.nav { display: flex; align-items: center; gap: 28px; }
.nav a { text-decoration: none; color: var(--text); font-size: 16px; }
.nav a:hover { color: var(--ink); }
.btn {
  display: inline-flex; align-items: center; justify-content: center; text-decoration: none;
  height: 44px; padding: 0 24px; border-radius: 999px; font-size: 15px; font-weight: 600; white-space: nowrap;
}
.btn-dark { background: var(--ink); color: #fff; }
.btn-dark:hover { background: #27272a; }
.nav .btn-dark { color: #fff; }

/* Index */
.page-head { padding: 88px 0 40px; }
.page-head h1 { margin: 0; font-size: clamp(44px, 7vw, 72px); line-height: 1.05; font-weight: 600; color: var(--ink); letter-spacing: -.02em; }
.page-head p { margin: 20px 0 0; max-width: 40em; color: var(--muted); }
.filters { display: flex; flex-wrap: wrap; gap: 8px; margin: 0 0 16px; padding: 0; list-style: none; }
.filters button {
  font: inherit; font-size: 14px; line-height: 1; padding: 10px 16px; border-radius: 999px; cursor: pointer;
  border: 1px solid var(--line); background: #fff; color: var(--text);
}
.filters button[aria-pressed="true"] { background: var(--ink); border-color: var(--ink); color: #fff; }
.post-list { list-style: none; margin: 0 0 120px; padding: 0; border-top: 1px solid var(--line); }
.post-list li { border-bottom: 1px solid var(--line); }
.post-list a { display: grid; grid-template-columns: 180px 1fr; gap: 24px; padding: 32px 0; text-decoration: none; }
.post-meta { font-size: 14px; color: var(--muted); line-height: 1.7; }
.post-meta .genre { display: block; color: var(--ink); }
.post-title { margin: 0; font-size: 21px; line-height: 1.55; font-weight: 600; color: var(--ink); }
.post-list a:hover .post-title { text-decoration: underline; text-underline-offset: 4px; text-decoration-thickness: 1px; }
.post-desc { margin: 8px 0 0; font-size: 15px; color: var(--muted); line-height: 1.8; }
.empty { padding: 48px 0; color: var(--muted); }

/* Article */
.article { max-width: var(--read); padding: 56px 0 96px; }
.crumb { font-size: 14px; color: var(--muted); margin: 0 0 40px; }
.crumb a { color: var(--muted); text-decoration: none; }
.crumb a:hover { color: var(--ink); }
.article-meta { font-size: 14px; color: var(--muted); margin: 0 0 16px; }
.article-meta .genre { color: var(--ink); margin-right: 16px; }
.article h1 { margin: 0 0 48px; font-size: clamp(28px, 4.2vw, 40px); line-height: 1.4; font-weight: 600; color: var(--ink); letter-spacing: -.01em; }
.prose > :first-child { margin-top: 0; }
.prose p { margin: 0 0 1.4em; }
.prose h2 { margin: 2.6em 0 .8em; font-size: 24px; line-height: 1.5; font-weight: 600; color: var(--ink); }
.prose h3 { margin: 2em 0 .6em; font-size: 19px; line-height: 1.5; font-weight: 600; color: var(--ink); }
.prose strong { color: var(--ink); font-weight: 600; }
.prose a { text-decoration: underline; text-underline-offset: 3px; text-decoration-thickness: 1px; color: var(--ink); }
.prose ul, .prose ol { margin: 0 0 1.4em; padding-left: 1.4em; }
.prose li { margin: .3em 0; }
.prose .table { overflow-x: auto; margin: 0 0 1.6em; }
.prose table { width: 100%; border-collapse: collapse; font-size: 15px; line-height: 1.7; min-width: 480px; }
.prose th, .prose td { text-align: left; padding: 12px 16px 12px 0; border-bottom: 1px solid var(--line); vertical-align: top; }
.prose th { font-weight: 600; color: var(--ink); border-bottom-color: var(--ink); }

.faq { margin-top: 72px; }
.faq h2 { margin: 0 0 8px; font-size: 24px; font-weight: 600; color: var(--ink); }
.faq details { border-bottom: 1px solid var(--line); }
.faq summary { cursor: pointer; list-style: none; padding: 20px 32px 20px 0; position: relative; font-weight: 600; color: var(--ink); line-height: 1.7; }
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after { content: "+"; position: absolute; right: 4px; top: 18px; font-weight: 400; font-size: 20px; color: var(--muted); }
.faq details[open] summary::after { content: "−"; }
.faq details p { margin: 0 0 20px; }

.byline { margin-top: 56px; padding-top: 24px; border-top: 1px solid var(--line); font-size: 14px; color: var(--muted); line-height: 1.9; }

.related { margin: 0 0 96px; max-width: var(--read); }
.related h2 { font-size: 18px; font-weight: 600; color: var(--ink); margin: 0 0 8px; }
.related .post-list { margin: 0; }
.related .post-list a { grid-template-columns: 1fr; gap: 4px; padding: 20px 0; }
.related .post-title { font-size: 17px; }

/* CTA band (same as LP) */
.cta {
  margin: 0 20px; border-radius: 48px; background: var(--panel); color: #fff; padding: 120px 0;
}
.cta h2 { margin: 0; font-size: clamp(36px, 6vw, 64px); line-height: 1.2; font-weight: 700; letter-spacing: -.01em; }
.cta p { margin: 24px 0 0; max-width: 30em; color: #a1a1aa; font-size: 17px; }
.cta .actions { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 40px; }
.cta .btn { height: 56px; padding: 0 32px; font-size: 16px; }
.btn-light { background: #fff; color: var(--ink); }
.btn-light:hover { background: #e4e4e7; }
.btn-outline { border: 1px solid #52525b; color: #fff; }
.btn-outline:hover { border-color: #fff; }
.cta .note { margin-top: 28px; font-size: 14px; color: #a1a1aa; }

/* Footer (same as LP + Articles) */
.site-footer { margin-top: 96px; border-top: 1px solid var(--line); padding: 48px 0 56px; }
.foot-nav { display: flex; flex-wrap: wrap; gap: 8px 28px; }
.foot-nav a { text-decoration: none; color: var(--text); }
.foot-nav a:hover, .foot-nav a[aria-current="page"] { color: var(--ink); text-decoration: underline; text-underline-offset: 4px; text-decoration-thickness: 1px; }
.foot-bottom { display: flex; justify-content: space-between; gap: 16px; margin-top: 40px; font-size: 14px; color: var(--muted); }

@media (max-width: 760px) {
  .nav a:not(.btn) { display: none; }
  .site-header .wrap { height: 64px; }
  .logo { font-size: 17px; }
  .btn { height: 40px; padding: 0 18px; font-size: 14px; }
  .page-head { padding: 56px 0 32px; }
  .post-list a { grid-template-columns: 1fr; gap: 6px; padding: 24px 0; }
  .post-meta .genre { display: inline; margin-right: 12px; }
  .post-title { font-size: 18px; }
  .article { padding-top: 32px; }
  .article h1 { margin-bottom: 36px; }
  .cta { margin: 0 12px; border-radius: 32px; padding: 72px 0; }
  .foot-bottom { flex-direction: column; }
}
@media (prefers-reduced-motion: reduce) { * { scroll-behavior: auto !important; transition: none !important; } }