/* ===== Reset & Base ===== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --primary: #6d28d9;
  --primary-dark: #5b21b6;
  --primary-light: #ede9fe;
  --bg: #f5f3ff;
  --surface: #ffffff;
  --surface2: #f8fafc;
  --border: #e2e8f0;
  --text: #0f172a;
  --text-muted: #64748b;
  --radius: 12px;
  --shadow: 0 2px 12px rgba(109,40,217,0.08);
  --shadow-lg: 0 8px 32px rgba(109,40,217,0.15);

  /* カテゴリカラー */
  --cat-llm: #7c3aed;
  --cat-llm-bg: #ede9fe;
  --cat-image: #db2777;
  --cat-image-bg: #fce7f3;
  --cat-product: #0891b2;
  --cat-product-bg: #e0f2fe;
  --cat-research: #16a34a;
  --cat-research-bg: #dcfce7;
  --cat-regulation: #dc2626;
  --cat-regulation-bg: #fee2e2;
  --cat-business: #d97706;
  --cat-business-bg: #fef3c7;
  --cat-other: #64748b;
  --cat-other-bg: #f1f5f9;
}

body {
  font-family: 'Segoe UI', 'Hiragino Sans', 'Meiryo', sans-serif;
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
}

/* ===== Back Bar ===== */
.flu-back-bar { background: var(--primary); padding: 8px 16px; }
.flu-back-btn { color: #fff; text-decoration: none; font-size: 13px; font-weight: 600; letter-spacing: 0.03em; }
.flu-back-btn:hover { text-decoration: underline; }

/* ===== Header ===== */
header {
  background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%);
  color: #fff;
  padding: 24px 0 20px;
  text-align: center;
  box-shadow: 0 2px 16px rgba(109,40,217,0.25);
}
.header-inner h1 { font-size: 2rem; font-weight: 700; letter-spacing: 0.05em; }
.header-inner .subtitle { font-size: 0.95rem; opacity: 0.82; margin-top: 4px; }
.header-updated { font-size: 0.78rem; opacity: 0.65; margin-top: 6px; }

/* ===== Layout ===== */
.page-wrap {
  max-width: 1100px;
  margin: 0 auto;
  padding: 28px 16px 60px;
  display: grid;
  grid-template-columns: 1fr 280px;
  gap: 28px;
  align-items: start;
}
@media (max-width: 800px) {
  .page-wrap { grid-template-columns: 1fr; }
  .sidebar { order: -1; }
}

/* ===== Category Filter ===== */
.category-filter {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 24px;
}
.cat-btn {
  padding: 6px 16px;
  border-radius: 20px;
  border: 2px solid var(--border);
  background: var(--surface);
  font-size: 0.85rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.18s;
  color: var(--text-muted);
}
.cat-btn:hover { border-color: var(--primary); color: var(--primary); background: var(--primary-light); }
.cat-btn.active { background: var(--primary); color: #fff; border-color: var(--primary); }

/* ===== Date Navigation ===== */
.date-nav {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 24px;
  flex-wrap: wrap;
}
.date-nav-btn {
  padding: 7px 14px;
  border: 1.5px solid var(--border);
  border-radius: 8px;
  background: var(--surface);
  font-size: 0.85rem;
  cursor: pointer;
  transition: all 0.15s;
  color: var(--text);
}
.date-nav-btn:hover { border-color: var(--primary); color: var(--primary); }
.date-nav-btn.active { background: var(--primary); color: #fff; border-color: var(--primary); }
.date-nav-label { font-size: 0.9rem; font-weight: 700; color: var(--primary-dark); white-space: nowrap; }

/* ===== Date Group ===== */
.date-group { margin-bottom: 36px; }
.date-group-header {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 16px;
  padding-bottom: 10px;
  border-bottom: 2px solid var(--primary-light);
}
.date-group-title {
  font-size: 1rem;
  font-weight: 700;
  color: var(--primary-dark);
}
.date-group-count {
  font-size: 0.78rem;
  background: var(--primary-light);
  color: var(--primary);
  padding: 2px 10px;
  border-radius: 20px;
  font-weight: 700;
}

/* ===== Article Cards ===== */
.articles-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 14px;
}

.article-card {
  background: var(--surface);
  border-radius: var(--radius);
  padding: 18px 20px;
  box-shadow: var(--shadow);
  border: 1px solid var(--border);
  transition: box-shadow 0.2s, transform 0.15s;
  display: flex;
  flex-direction: column;
  gap: 8px;
}
.article-card:hover {
  box-shadow: var(--shadow-lg);
  transform: translateY(-2px);
}

.article-card-top {
  display: flex;
  align-items: center;
  gap: 8px;
  flex-wrap: wrap;
}

.category-badge {
  display: inline-block;
  font-size: 0.72rem;
  font-weight: 700;
  padding: 2px 10px;
  border-radius: 20px;
  white-space: nowrap;
}
.badge-LLM        { background: var(--cat-llm-bg);         color: var(--cat-llm); }
.badge-画像生成   { background: var(--cat-image-bg);       color: var(--cat-image); }
.badge-製品       { background: var(--cat-product-bg);     color: var(--cat-product); }
.badge-研究       { background: var(--cat-research-bg);    color: var(--cat-research); }
.badge-規制       { background: var(--cat-regulation-bg);  color: var(--cat-regulation); }
.badge-ビジネス   { background: var(--cat-business-bg);    color: var(--cat-business); }
.badge-その他     { background: var(--cat-other-bg);       color: var(--cat-other); }

.article-source {
  font-size: 0.75rem;
  color: var(--text-muted);
  display: flex;
  align-items: center;
  gap: 4px;
}
.article-source::before { content: '📰'; font-size: 0.7rem; }

.article-date-time {
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-left: auto;
  white-space: nowrap;
}

.article-title {
  font-size: 1rem;
  font-weight: 700;
  color: var(--text);
  line-height: 1.5;
}
.article-title a {
  color: inherit;
  text-decoration: none;
}
.article-title a:hover { color: var(--primary); text-decoration: underline; }

.article-summary {
  font-size: 0.875rem;
  color: var(--text-muted);
  line-height: 1.7;
}

.article-read-btn {
  align-self: flex-start;
  margin-top: 4px;
  padding: 6px 16px;
  background: var(--primary-light);
  color: var(--primary);
  border-radius: 8px;
  font-size: 0.82rem;
  font-weight: 700;
  text-decoration: none;
  transition: background 0.15s, color 0.15s;
  display: inline-flex;
  align-items: center;
  gap: 4px;
}
.article-read-btn:hover { background: var(--primary); color: #fff; }

/* ===== Load More ===== */
.load-more-wrap { text-align: center; margin-top: 28px; }
.load-more-btn {
  padding: 12px 32px;
  background: var(--surface);
  border: 2px solid var(--primary);
  color: var(--primary);
  border-radius: 10px;
  font-size: 0.95rem;
  font-weight: 700;
  cursor: pointer;
  transition: all 0.18s;
}
.load-more-btn:hover { background: var(--primary); color: #fff; }

/* ===== Empty State ===== */
.empty-state {
  text-align: center;
  padding: 48px 16px;
  color: var(--text-muted);
  font-size: 0.95rem;
}
.empty-state .empty-icon { font-size: 2.5rem; margin-bottom: 12px; }

/* ===== Sidebar ===== */
.sidebar { display: flex; flex-direction: column; gap: 20px; }

.sidebar-card {
  background: var(--surface);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  overflow: hidden;
}
.sidebar-card-header {
  background: var(--primary);
  color: #fff;
  padding: 12px 16px;
  font-size: 0.9rem;
  font-weight: 700;
}
.sidebar-card-body { padding: 14px 16px; }

/* Archive list */
.archive-list { list-style: none; }
.archive-list li {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 8px 0;
  border-bottom: 1px solid var(--border);
  font-size: 0.88rem;
}
.archive-list li:last-child { border-bottom: none; }
.archive-list a {
  color: var(--primary-dark);
  text-decoration: none;
  font-weight: 600;
  cursor: pointer;
}
.archive-list a:hover { text-decoration: underline; }
.archive-count {
  background: var(--primary-light);
  color: var(--primary);
  border-radius: 20px;
  padding: 1px 9px;
  font-size: 0.75rem;
  font-weight: 700;
}

/* Category stats */
.cat-stat-list { list-style: none; display: flex; flex-direction: column; gap: 8px; }
.cat-stat-item {
  display: flex;
  justify-content: space-between;
  align-items: center;
  cursor: pointer;
  padding: 4px 0;
}
.cat-stat-item:hover .cat-stat-name { color: var(--primary); }
.cat-stat-name { font-size: 0.88rem; font-weight: 600; color: var(--text); }
.cat-stat-bar-wrap { flex: 1; margin: 0 10px; height: 6px; background: var(--border); border-radius: 3px; overflow: hidden; }
.cat-stat-bar { height: 100%; border-radius: 3px; transition: width 0.4s; }
.cat-stat-num { font-size: 0.78rem; color: var(--text-muted); min-width: 24px; text-align: right; }

/* ===== Loading spinner ===== */
.spinner {
  text-align: center;
  padding: 48px 16px;
  color: var(--text-muted);
  font-size: 0.95rem;
}
.spinner::before { content: ''; display: block; width: 32px; height: 32px; border: 3px solid var(--border); border-top-color: var(--primary); border-radius: 50%; animation: spin 0.7s linear infinite; margin: 0 auto 12px; }
@keyframes spin { to { transform: rotate(360deg); } }

/* ===== 関連ツール ===== */
.related-tools {
  margin: 2rem auto;
  padding: 1.5rem;
  max-width: 1100px;
  background: var(--surface);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  text-align: center;
}
.related-tools h2 { font-size: 1.2rem; margin-bottom: 0.8rem; color: var(--primary); }
.related-tools p { color: var(--text-muted); margin-bottom: 1rem; font-size: 0.9rem; }
.tool-links { display: flex; flex-wrap: wrap; justify-content: center; gap: 0.8rem; }
.tool-card {
  display: inline-block; padding: 0.7rem 1.1rem;
  background: var(--primary-light); border: 1px solid var(--primary);
  border-radius: 10px; text-decoration: none; color: var(--primary);
  font-weight: 600; font-size: 0.88rem; transition: all 0.2s;
}
.tool-card:hover { background: var(--primary); color: #fff; transform: translateY(-2px); }

/* ===== Footer ===== */
footer {
  text-align: center; padding: 1.5rem 0;
  background: #f1f5f9; color: #555;
  font-size: 0.9rem; border-top: 1px solid #e2e8f0; margin-top: 2rem;
}
.footer-nav a { color: var(--primary); text-decoration: none; margin: 0 0.5rem; }
.footer-nav a:hover { text-decoration: underline; }

/* ===== SEO用メタ情報 ===== */
.seo-intro {
  max-width: 1100px;
  margin: 0 auto 4px;
  padding: 10px 16px 0;
  font-size: 0.82rem;
  color: var(--text-muted);
}