/* リセットと基本設定 */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

:root {
  --primary-color: #2563eb;
  --secondary-color: #1e40af;
  --text-primary: #1f2937;
  --text-secondary: #6b7280;
  --bg-primary: #ffffff;
  --bg-secondary: #f9fafb;
  --border-color: #e5e7eb;
  --accent-color: #10b981;
  --max-width: 1200px;
}

body {
  font-family: 'Inter', 'Noto Sans JP', -apple-system, BlinkMacSystemFont, sans-serif;
  line-height: 1.6;
  color: var(--text-primary);
  background-color: var(--bg-primary);
}

/* キーボード操作向けフォーカス表示 */
a:focus-visible, button:focus-visible, [tabindex]:focus-visible {
  outline: 2px solid var(--primary-color);
  outline-offset: 2px;
}

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 20px;
}

/* ヘッダー */
.header {
  background: var(--bg-primary);
  border-bottom: 1px solid var(--border-color);
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(10px);
  background: rgba(255, 255, 255, 0.95);
}

.header-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1.5rem 0;
}

.logo {
  text-decoration: none;
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-primary);
  display: flex;
  align-items: center;
}

.logo-text {
  background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.nav {
  display: flex;
  gap: 2rem;
}

.nav-link {
  text-decoration: none;
  color: var(--text-secondary);
  font-weight: 500;
  transition: color 0.3s ease;
}

.nav-link:hover {
  color: var(--primary-color);
}

/* ヒーローセクション */
.hero {
  padding: 5rem 0;
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  color: white;
  text-align: center;
}

.hero-title {
  font-size: 3rem;
  font-weight: 700;
  margin-bottom: 1rem;
  line-height: 1.2;
}

.hero-subtitle {
  font-size: 1.25rem;
  opacity: 0.95;
  max-width: 600px;
  margin: 0 auto 2rem;
}

.hero-links {
  display: flex;
  justify-content: center;
  gap: 1rem;
  flex-wrap: wrap;
}

.hero-link {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.75rem 1.5rem;
  background: rgba(255, 255, 255, 0.2);
  color: white;
  text-decoration: none;
  border-radius: 8px;
  font-weight: 500;
  backdrop-filter: blur(10px);
  transition: all 0.3s ease;
  border: 1px solid rgba(255, 255, 255, 0.3);
}

.hero-link:hover {
  background: rgba(255, 255, 255, 0.3);
  transform: translateY(-2px);
}

.hero-link-icon {
  width: 20px;
  height: 20px;
}

/* セクション共通 */
.section {
  padding: 4rem 0;
  /* 固定ヘッダー分のオフセットでアンカー位置を補正 */
  scroll-margin-top: 80px;
}

.section-alt {
  background-color: var(--bg-secondary);
}

.section-title {
  font-size: 2rem;
  font-weight: 700;
  text-align: center;
  margin-bottom: 3rem;
  color: var(--text-primary);
}

/* 記事グリッド */
.articles-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 2rem;
}

.article-card {
  background: var(--bg-primary);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  padding: 1.5rem;
  transition: all 0.3s ease;
}

.article-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
}

.article-date {
  color: var(--text-secondary);
  font-size: 0.875rem;
  margin-bottom: 0.5rem;
}

.article-title {
  font-size: 1.25rem;
  font-weight: 600;
  margin-bottom: 0.75rem;
  color: var(--text-primary);
}

.article-excerpt {
  color: var(--text-secondary);
  line-height: 1.6;
  margin-bottom: 1rem;
}

.article-link {
  color: var(--primary-color);
  text-decoration: none;
  font-weight: 500;
  display: inline-flex;
  align-items: center;
  transition: color 0.3s ease;
}

.article-link:hover {
  color: var(--secondary-color);
}

/* プロジェクトグリッド */
.projects-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(360px, 1fr));
  gap: 2rem;
}

.project-card {
  background: var(--bg-primary);
  border-radius: 12px;
  padding: 2rem;
  border: 1px solid var(--border-color);
  transition: all 0.3s ease;
}

.project-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
}

.project-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 1rem;
}

.project-title {
  font-size: 1.5rem;
  font-weight: 600;
  color: var(--text-primary);
}

.project-status {
  padding: 0.25rem 0.75rem;
  background: var(--accent-color);
  color: white;
  border-radius: 20px;
  font-size: 0.875rem;
  font-weight: 500;
}

/* 計画中バッジ（HTML側で data-status="planned" を付与） */
.project-status[data-status="planned"] {
  background: var(--text-secondary);
}

.project-description {
  color: var(--text-secondary);
  line-height: 1.6;
  margin-bottom: 1.5rem;
}

.project-tech {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-bottom: 1.5rem;
}

.tech-tag {
  padding: 0.25rem 0.75rem;
  background: var(--bg-secondary);
  color: var(--text-primary);
  border-radius: 6px;
  font-size: 0.875rem;
  font-weight: 500;
  border: 1px solid var(--border-color);
}

.project-link {
  color: var(--primary-color);
  text-decoration: none;
  font-weight: 500;
  display: inline-flex;
  align-items: center;
  transition: color 0.3s ease;
}

.project-link:hover {
  color: var(--secondary-color);
}

/* Aboutセクション */
.about-content {
  max-width: 800px;
  margin: 0 auto;
  text-align: center;
}

.about-content p {
  margin-bottom: 1.5rem;
  color: var(--text-secondary);
  line-height: 1.8;
  font-size: 1.125rem;
}

/* フッター */
.footer {
  background: var(--text-primary);
  color: white;
  padding: 2rem 0;
  margin-top: 4rem;
}

.footer-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 1rem;
}

.footer-links {
  display: flex;
  gap: 2rem;
}

.footer-link {
  color: rgba(255, 255, 255, 0.8);
  text-decoration: none;
  transition: color 0.3s ease;
}

.footer-link:hover {
  color: white;
}

/* レスポンシブデザイン */
@media (max-width: 768px) {
  .hero-title {
    font-size: 2rem;
  }
  
  .hero-subtitle {
    font-size: 1rem;
  }
  
  .nav {
    gap: 1rem;
  }
  
  .nav-link {
    font-size: 0.875rem;
  }
  
  .articles-grid,
  .projects-grid {
    grid-template-columns: 1fr;
  }
  
  .footer-content {
    flex-direction: column;
    text-align: center;
  }
  
  .section {
    padding: 3rem 0;
  }
}

@media (max-width: 480px) {
  .header-content {
    flex-direction: column;
    gap: 1rem;
  }
  
  .hero {
    padding: 3rem 0;
  }
  
  .hero-title {
    font-size: 1.75rem;
  }
  
  .container {
    padding: 0 15px;
  }
}