/*
 * A2B2 Blog public — Visual System
 *
 * Mirrors the marketing site's dark navy + amber + glass treatment so the
 * blog (server-rendered by BlogPageController via Thymeleaf) reads as the
 * same product as the marketing landing.
 *
 * SOURCE OF TRUTH for tokens: docs/product/Design-Token-web(参考).md.
 * Marketing analog: frontend/web-marketing/src/app/globals.css.
 * Keep these two files visually in sync — when one changes, update the other.
 */

:root {
  /* ── Surfaces ── */
  --bg-base:        #0C1018;
  --bg-sidebar:     #182640;
  --bg-card:        #1E2E48;
  --bg-card-hover:  #243454;
  --bg-elevated:    #243050;
  --bg-input:       #0F1C30;

  /* ── Brand: Amber ── */
  --amber:          #E8B44F;
  --amber-hover:    #F0C060;
  --amber-light:    rgba(232, 180, 79, 0.15);
  --on-amber:       #0D1520;

  /* ── Text ── */
  --text:           #F0F0F0;
  --text-2:         rgba(255, 255, 255, 0.60);
  --text-3:         rgba(255, 255, 255, 0.38);

  /* ── Border ── */
  --border:         rgba(255, 255, 255, 0.09);
  --border-2:       rgba(255, 255, 255, 0.16);
  --divider:        rgba(255, 255, 255, 0.06);

  /* ── Radius ── */
  --r-md:    8px;
  --r-card:  12px;
  --r-lg:    16px;
  --r-pill:  9999px;

  /* ── Spacing ── */
  --sp-1: 4px;
  --sp-2: 8px;
  --sp-3: 12px;
  --sp-4: 16px;
  --sp-5: 24px;
  --sp-6: 32px;
  --sp-8: 48px;
  --sp-10: 64px;
  --sp-12: 96px;
  --sp-16: 128px;

  --shadow-card:    0 1px 6px rgba(0, 0, 0, 0.35);
  --shadow-float:   0 4px 20px rgba(0, 0, 0, 0.55);

  --font-sans:  "Inter", -apple-system, BlinkMacSystemFont, "Helvetica Neue", sans-serif;
  --font-serif: "Georgia", "Playfair Display", "Times New Roman", serif;
  --font-mono:  "SF Mono", "Menlo", "Courier New", monospace;

  --content-narrow: min(60rem, calc(100vw - 64px));
  --content-wide:   min(74rem, calc(100vw - 64px));
  --nav-height:     56px;
}

* { margin: 0; padding: 0; box-sizing: border-box; }

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

body {
  font-family: var(--font-sans);
  font-size: 14px;
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

a { color: inherit; text-decoration: none; }
a:focus-visible {
  outline: 2px solid var(--amber);
  outline-offset: 2px;
  border-radius: var(--r-md);
}

.editorial-accent {
  font-family: var(--font-serif);
  font-style: italic;
  font-weight: 400;
  color: var(--amber);
}

.glass-card {
  background:
    linear-gradient(135deg, rgba(255, 255, 255, 0.045) 0%, rgba(255, 255, 255, 0.02) 100%);
  backdrop-filter: blur(20px) saturate(140%);
  -webkit-backdrop-filter: blur(20px) saturate(140%);
  border: 1px solid rgba(255, 255, 255, 0.07);
  border-radius: var(--r-card);
}

.glass-card-strong {
  background:
    linear-gradient(135deg, rgba(255, 255, 255, 0.07) 0%, rgba(255, 255, 255, 0.03) 100%);
  backdrop-filter: blur(24px) saturate(160%);
  -webkit-backdrop-filter: blur(24px) saturate(160%);
  border: 1px solid rgba(255, 255, 255, 0.09);
  border-radius: var(--r-card);
}

/* ─────────────────────────────────────────────────
   Top nav — minimal, reads same as marketing nav
───────────────────────────────────────────────── */
.blog-nav {
  position: sticky;
  top: 0;
  z-index: 50;
  background: color-mix(in srgb, var(--bg-base) 80%, transparent);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
}
.blog-nav__inner {
  margin: 0 auto;
  max-width: var(--content-wide);
  height: var(--nav-height);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 var(--sp-6);
}
.blog-nav__brand {
  display: inline-flex;
  align-items: center;
  gap: var(--sp-2);
  color: var(--text);
  font-weight: 600;
  font-size: 15px;
}
.blog-nav__brand-mark {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 28px;
  height: 28px;
  border-radius: var(--r-md);
  background: var(--amber);
  color: var(--on-amber);
  font-size: 10px;
  font-weight: 700;
}
.blog-nav__links {
  display: inline-flex;
  align-items: center;
  gap: var(--sp-6);
  list-style: none;
}
.blog-nav__links a {
  font-size: 13px;
  font-weight: 500;
  color: var(--text-3);
  transition: color 120ms;
}
.blog-nav__links a:hover { color: var(--text); }
.blog-nav__lang {
  display: inline-flex;
  align-items: center;
  border-radius: var(--r-pill);
  background: linear-gradient(135deg, rgba(255, 255, 255, 0.07), rgba(255, 255, 255, 0.03));
  border: 1px solid rgba(255, 255, 255, 0.09);
  padding: 3px;
  gap: 0;
}
.blog-nav__lang a {
  padding: 4px 12px;
  font-size: 11px;
  font-weight: 600;
  border-radius: var(--r-pill);
  color: var(--text-3);
  transition: color 120ms;
}
.blog-nav__lang a:hover { color: var(--text); }
.blog-nav__lang a.active {
  background: var(--amber);
  color: var(--on-amber);
}
@media (max-width: 720px) {
  .blog-nav__links { display: none; }
}

/* ─────────────────────────────────────────────────
   Page chrome
───────────────────────────────────────────────── */
.blog-shell {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}
.blog-main { flex: 1; }

.blog-eyebrow {
  display: inline-block;
  font-size: 11px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.16em;
  color: var(--amber);
}

.blog-h1 {
  font-size: clamp(2rem, 4.5vw, 3.25rem);
  font-weight: 700;
  line-height: 1.08;
  letter-spacing: -0.02em;
  color: var(--text);
}

.blog-lede {
  margin-top: var(--sp-4);
  font-size: 16px;
  line-height: 1.7;
  color: var(--text-2);
}

/* ─────────────────────────────────────────────────
   Index — categories + grouped article cards
───────────────────────────────────────────────── */
.blog-index {
  margin: 0 auto;
  max-width: var(--content-wide);
  padding: var(--sp-12) var(--sp-6) var(--sp-16);
}
.blog-index__hero { text-align: center; max-width: 44rem; margin: 0 auto; }

.blog-category {
  margin-top: var(--sp-12);
}
.blog-category__name {
  font-size: 12px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.14em;
  color: var(--text-3);
  margin-bottom: var(--sp-5);
  padding-bottom: var(--sp-3);
  border-bottom: 1px solid var(--divider);
}

.blog-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(20rem, 1fr));
  gap: var(--sp-5);
}

.blog-card {
  display: flex;
  flex-direction: column;
  padding: var(--sp-5);
  transition: transform 180ms, border-color 180ms, background 180ms;
  text-decoration: none;
  color: inherit;
}
.blog-card:hover {
  transform: translateY(-2px);
  border-color: rgba(255, 255, 255, 0.12);
}
.blog-card__cover {
  margin: calc(-1 * var(--sp-5)) calc(-1 * var(--sp-5)) var(--sp-4);
  aspect-ratio: 4 / 3;
  background-position: center;
  background-size: cover;
  background-color: var(--bg-input);
  border-top-left-radius: var(--r-card);
  border-top-right-radius: var(--r-card);
  overflow: hidden;
}
.blog-card__title {
  font-size: 17px;
  font-weight: 600;
  line-height: 1.35;
  color: var(--text);
}
.blog-card__summary {
  margin-top: var(--sp-2);
  font-size: 13px;
  line-height: 1.65;
  color: var(--text-2);
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}
.blog-card__meta {
  margin-top: var(--sp-4);
  padding-top: var(--sp-3);
  font-size: 11px;
  color: var(--text-3);
  display: flex;
  gap: var(--sp-3);
  align-items: center;
  flex-wrap: wrap;
}
.blog-card__author {
  font-weight: 500;
  color: var(--text-2);
}

/* ─────────────────────────────────────────────────
   Article — long-form prose + sidebar
───────────────────────────────────────────────── */
.blog-article {
  margin: 0 auto;
  max-width: var(--content-wide);
  padding: var(--sp-10) var(--sp-6) var(--sp-16);
  display: grid;
  grid-template-columns: 240px minmax(0, 1fr);
  gap: var(--sp-12);
}
@media (max-width: 920px) {
  .blog-article { grid-template-columns: 1fr; gap: var(--sp-8); }
  .blog-sidebar { order: 2; }
}

.blog-sidebar {
  position: sticky;
  top: calc(var(--nav-height) + var(--sp-5));
  align-self: start;
  max-height: calc(100vh - var(--nav-height) - var(--sp-5));
  overflow-y: auto;
  padding-right: var(--sp-2);
}
.blog-sidebar__group { margin-bottom: var(--sp-6); }
.blog-sidebar__category {
  font-size: 10px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.14em;
  color: var(--text-3);
  margin-bottom: var(--sp-3);
}
.blog-sidebar__list { list-style: none; display: flex; flex-direction: column; gap: var(--sp-2); }
.blog-sidebar__link {
  display: block;
  font-size: 13px;
  line-height: 1.45;
  color: var(--text-2);
  padding: 6px 8px;
  border-radius: 6px;
  transition: color 120ms, background 120ms;
}
.blog-sidebar__link:hover { color: var(--text); background: rgba(255, 255, 255, 0.04); }
.blog-sidebar__link.active { color: var(--amber); background: var(--amber-light); }

.blog-article__header {
  max-width: 44rem;
  margin-bottom: var(--sp-8);
}
.blog-article__category {
  display: inline-block;
  font-size: 11px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.14em;
  color: var(--amber);
  margin-bottom: var(--sp-4);
}
.blog-article__title {
  font-size: clamp(2rem, 4.5vw, 3rem);
  font-weight: 700;
  line-height: 1.1;
  letter-spacing: -0.02em;
  color: var(--text);
}
.blog-article__lede {
  margin-top: var(--sp-4);
  font-size: 17px;
  line-height: 1.7;
  color: var(--text-2);
}
.blog-article__meta {
  margin-top: var(--sp-5);
  display: flex;
  flex-wrap: wrap;
  gap: var(--sp-3);
  font-size: 12px;
  color: var(--text-3);
}
.blog-article__cover {
  aspect-ratio: 16 / 9;
  background-size: cover;
  background-position: center;
  background-color: var(--bg-input);
  border-radius: var(--r-card);
  margin-bottom: var(--sp-8);
}

/* Long-form prose — applies to BlogMarkdownRenderer output */
.blog-prose {
  max-width: 44rem;
  font-size: 16px;
  line-height: 1.75;
  color: var(--text-2);
}
.blog-prose p { margin: 0 0 var(--sp-5); }
.blog-prose h2 {
  margin: var(--sp-10) 0 var(--sp-4);
  font-size: clamp(1.5rem, 2.5vw, 1.875rem);
  font-weight: 700;
  line-height: 1.25;
  letter-spacing: -0.015em;
  color: var(--text);
}
.blog-prose h3 {
  margin: var(--sp-8) 0 var(--sp-3);
  font-size: 1.25rem;
  font-weight: 600;
  line-height: 1.3;
  color: var(--text);
}
.blog-prose h4 {
  margin: var(--sp-6) 0 var(--sp-2);
  font-size: 1rem;
  font-weight: 600;
  color: var(--text);
}
.blog-prose a { color: var(--amber); text-decoration: underline; text-underline-offset: 3px; }
.blog-prose a:hover { color: var(--amber-hover); }
.blog-prose strong { color: var(--text); font-weight: 600; }
.blog-prose em { color: var(--text); font-style: italic; }
.blog-prose ul, .blog-prose ol { margin: 0 0 var(--sp-5) var(--sp-6); }
.blog-prose li { margin-bottom: var(--sp-2); }
.blog-prose blockquote {
  margin: var(--sp-6) 0;
  padding: var(--sp-4) var(--sp-6);
  border-left: 2px solid var(--amber);
  font-family: var(--font-serif);
  font-style: italic;
  font-size: 18px;
  color: var(--text);
}
.blog-prose code {
  font-family: var(--font-mono);
  font-size: 0.875em;
  background: rgba(255, 255, 255, 0.06);
  padding: 2px 6px;
  border-radius: 4px;
  color: var(--text);
}
.blog-prose pre {
  margin: var(--sp-5) 0;
  padding: var(--sp-4);
  background: var(--bg-input);
  border-radius: var(--r-card);
  overflow-x: auto;
  font-size: 13px;
  line-height: 1.6;
}
.blog-prose pre code {
  background: transparent;
  padding: 0;
  color: var(--text);
}
.blog-prose img {
  max-width: 100%;
  height: auto;
  border-radius: var(--r-card);
  margin: var(--sp-5) 0;
}
.blog-prose hr {
  margin: var(--sp-8) 0;
  border: 0;
  border-top: 1px solid var(--divider);
}
.blog-prose table {
  width: 100%;
  border-collapse: collapse;
  font-size: 14px;
  margin: var(--sp-5) 0;
}
.blog-prose th, .blog-prose td {
  padding: var(--sp-3);
  text-align: left;
  border-bottom: 1px solid var(--divider);
}
.blog-prose th {
  color: var(--text);
  font-weight: 600;
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

/* ─────────────────────────────────────────────────
   Preview banner (admin signed-token preview)
───────────────────────────────────────────────── */
.blog-preview-banner {
  background: var(--amber-light);
  border-bottom: 1px solid rgba(232, 180, 79, 0.32);
  color: var(--amber);
  text-align: center;
  padding: 8px var(--sp-6);
  font-size: 12px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.1em;
}

/* ─────────────────────────────────────────────────
   Footer — minimal, mirrors marketing footer
───────────────────────────────────────────────── */
.blog-footer {
  margin-top: auto;
  background: var(--bg-base);
  padding: var(--sp-12) 0 var(--sp-8);
}
.blog-footer__inner {
  margin: 0 auto;
  max-width: var(--content-wide);
  padding: 0 var(--sp-6);
}
.blog-footer__legal {
  font-size: 11px;
  line-height: 1.7;
  color: var(--text-3);
  max-width: 44rem;
  margin-bottom: var(--sp-3);
}
.blog-footer__bar {
  display: flex;
  flex-wrap: wrap;
  gap: var(--sp-3);
  font-size: 11px;
  color: var(--text-3);
}
.blog-footer__bar a {
  color: var(--text-2);
  transition: color 120ms;
}
.blog-footer__bar a:hover { color: var(--text); }
.blog-footer__sep::after {
  content: "·";
  margin-left: var(--sp-3);
  color: var(--text-3);
}

/* ─────────────────────────────────────────────────
   Empty state
───────────────────────────────────────────────── */
.blog-empty {
  margin: var(--sp-16) auto;
  max-width: 32rem;
  text-align: center;
  color: var(--text-3);
  font-size: 15px;
}

/*
 * Article-not-found / 404 surface. Same visual rhythm as the index hero
 * (eyebrow → headline with editorial-accent → lede), so a missing article
 * feels like a deliberate page rather than a server error.
 */
.blog-empty-state {
  margin: clamp(var(--sp-12), 14vh, var(--sp-16)) auto;
  max-width: var(--content-narrow);
  padding: 0 var(--sp-6);
  text-align: center;
}
.blog-empty-state .blog-h1 { margin-top: var(--sp-4); }
.blog-empty-state .blog-lede { margin-left: auto; margin-right: auto; max-width: 36rem; }

.blog-empty-state__actions {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: var(--sp-3);
  margin-top: var(--sp-8);
}

.blog-empty-state__primary {
  display: inline-flex;
  align-items: center;
  height: 44px;
  padding: 0 var(--sp-6);
  border-radius: var(--r-pill);
  background: var(--amber);
  color: var(--on-amber);
  font-size: 14px;
  font-weight: 600;
  text-decoration: none;
  transition: background 120ms ease-out;
}
.blog-empty-state__primary:hover { background: var(--amber-hover); }

.blog-empty-state__secondary {
  display: inline-flex;
  align-items: center;
  height: 44px;
  padding: 0 var(--sp-6);
  border-radius: var(--r-pill);
  border: 1px solid var(--border-2);
  background: rgba(255, 255, 255, 0.04);
  color: var(--text);
  font-size: 14px;
  font-weight: 500;
  text-decoration: none;
  transition: background 120ms ease-out;
}
.blog-empty-state__secondary:hover { background: rgba(255, 255, 255, 0.08); }

/*
 * End-of-article CTA. Sits below blog-prose, gives the reader the
 * editorial-brief-defined next step (e.g. "What A2B2 is →"). Visual
 * weight on par with the homepage Hero primary so the path forward
 * is obvious; deliberately left-aligned to match prose flow rather
 * than centred (centred CTAs read like a marketing footer).
 */
.blog-article__cta-wrap {
  margin-top: var(--sp-12);
  padding-top: var(--sp-8);
  border-top: 1px solid var(--divider, var(--border));
}

.blog-article__cta {
  display: inline-flex;
  align-items: center;
  height: 44px;
  padding: 0 var(--sp-6);
  border-radius: var(--r-pill);
  background: var(--amber);
  color: var(--on-amber);
  font-size: 14px;
  font-weight: 600;
  text-decoration: none;
  transition: background 120ms ease-out;
}
.blog-article__cta:hover { background: var(--amber-hover); }