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

body {
  font-family: 'Hiragino Kaku Gothic ProN', 'Noto Sans JP', sans-serif;
  background: #f9f9f9;
  color: #333;
  line-height: 1.8;
}

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

/* Header */
header {
  background: #fff;
  border-bottom: 3px solid #2c7a7b;
  padding: 20px 0;
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: 0 2px 8px rgba(0,0,0,0.05);
}

.header-inner {
  max-width: 900px;
  margin: 0 auto;
  padding: 0 20px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 10px;
}

.site-title {
  font-size: 1.5rem;
  font-weight: 700;
  color: #2c7a7b;
  letter-spacing: 0.05em;
}

.site-title span {
  font-size: 0.9rem;
  color: #888;
  display: block;
  font-weight: 400;
}

nav a {
  margin-left: 20px;
  font-size: 0.9rem;
  color: #555;
  font-weight: 500;
  transition: color 0.2s;
}

nav a:hover {
  color: #2c7a7b;
}

/* Hero */
.hero {
  background: linear-gradient(135deg, #e6f4f4 0%, #f0fafa 100%);
  padding: 60px 20px;
  text-align: center;
}

.hero h2 {
  font-size: 1.8rem;
  color: #2c7a7b;
  margin-bottom: 10px;
}

.hero p {
  color: #666;
  font-size: 1rem;
}

/* Categories */
.categories {
  max-width: 900px;
  margin: 40px auto 10px;
  padding: 0 20px;
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
}

.category-btn {
  padding: 6px 16px;
  border-radius: 20px;
  border: 2px solid #2c7a7b;
  color: #2c7a7b;
  font-size: 0.85rem;
  font-weight: 600;
  cursor: pointer;
  background: #fff;
  transition: all 0.2s;
}

.category-btn:hover,
.category-btn.active {
  background: #2c7a7b;
  color: #fff;
}

/* Main */
main {
  max-width: 900px;
  margin: 0 auto;
  padding: 20px;
}

.section-title {
  font-size: 1.2rem;
  font-weight: 700;
  color: #333;
  margin: 30px 0 15px;
  padding-left: 10px;
  border-left: 4px solid #2c7a7b;
}

/* Card Grid */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 20px;
}

.card {
  background: #fff;
  border-radius: 12px;
  overflow: hidden;
  box-shadow: 0 2px 10px rgba(0,0,0,0.07);
  transition: transform 0.2s, box-shadow 0.2s;
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: 0 6px 20px rgba(0,0,0,0.12);
}

.card-img {
  width: 100%;
  height: 160px;
  object-fit: cover;
  background: linear-gradient(135deg, #2c7a7b, #48a999);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 3rem;
}

.card-body {
  padding: 16px;
}

.card-tag {
  display: inline-block;
  background: #e6f4f4;
  color: #2c7a7b;
  font-size: 0.75rem;
  font-weight: 700;
  padding: 2px 10px;
  border-radius: 4px;
  margin-bottom: 8px;
}

.card-title {
  font-size: 1rem;
  font-weight: 700;
  line-height: 1.5;
  margin-bottom: 8px;
  color: #222;
}

.card-excerpt {
  font-size: 0.85rem;
  color: #777;
  line-height: 1.6;
  margin-bottom: 12px;
}

.card-meta {
  font-size: 0.78rem;
  color: #aaa;
  display: flex;
  justify-content: space-between;
}

/* Article Page */
.article-header {
  max-width: 760px;
  margin: 40px auto 0;
  padding: 0 20px;
}

.article-tag {
  display: inline-block;
  background: #e6f4f4;
  color: #2c7a7b;
  font-size: 0.8rem;
  font-weight: 700;
  padding: 3px 12px;
  border-radius: 4px;
  margin-bottom: 12px;
}

.article-title {
  font-size: 1.8rem;
  font-weight: 700;
  line-height: 1.4;
  margin-bottom: 12px;
  color: #222;
}

.article-meta {
  font-size: 0.85rem;
  color: #999;
  margin-bottom: 30px;
}

.article-body {
  max-width: 760px;
  margin: 0 auto 60px;
  padding: 0 20px;
}

.article-body h2 {
  font-size: 1.3rem;
  font-weight: 700;
  color: #2c7a7b;
  margin: 40px 0 15px;
  padding: 10px 15px;
  background: #e6f4f4;
  border-radius: 6px;
}

.article-body h3 {
  font-size: 1.1rem;
  font-weight: 700;
  margin: 30px 0 10px;
  padding-left: 12px;
  border-left: 3px solid #2c7a7b;
}

.article-body p {
  margin-bottom: 16px;
  font-size: 1rem;
  color: #444;
}

.article-body ul, .article-body ol {
  margin: 0 0 16px 20px;
  font-size: 1rem;
  color: #444;
}

.article-body li {
  margin-bottom: 6px;
}

.highlight-box {
  background: #fff8e1;
  border-left: 4px solid #f6ad55;
  padding: 16px 20px;
  border-radius: 6px;
  margin: 20px 0;
  font-size: 0.95rem;
}

/* About */
.about-section {
  max-width: 760px;
  margin: 40px auto 60px;
  padding: 0 20px;
}

.profile-card {
  background: #fff;
  border-radius: 12px;
  padding: 30px;
  box-shadow: 0 2px 10px rgba(0,0,0,0.07);
  display: flex;
  gap: 24px;
  align-items: flex-start;
  margin-bottom: 30px;
  flex-wrap: wrap;
}

.profile-icon {
  width: 90px;
  height: 90px;
  background: linear-gradient(135deg, #2c7a7b, #48a999);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 2.5rem;
  flex-shrink: 0;
}

.profile-info h2 {
  font-size: 1.3rem;
  font-weight: 700;
  margin-bottom: 6px;
}

.profile-info p {
  font-size: 0.9rem;
  color: #666;
}

.tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 10px;
}

.tag {
  background: #e6f4f4;
  color: #2c7a7b;
  font-size: 0.8rem;
  font-weight: 600;
  padding: 4px 12px;
  border-radius: 20px;
}

/* Footer */
footer {
  background: #fff;
  border-top: 1px solid #eee;
  text-align: center;
  padding: 30px 20px;
  font-size: 0.85rem;
  color: #aaa;
}

footer a {
  color: #2c7a7b;
  margin: 0 8px;
}

/* Back link */
.back-link {
  display: inline-block;
  margin: 30px 0 0;
  font-size: 0.9rem;
  color: #2c7a7b;
  font-weight: 600;
}

.back-link::before {
  content: '← ';
}

@media (max-width: 600px) {
  .site-title {
    font-size: 1.2rem;
  }
  .hero h2 {
    font-size: 1.3rem;
  }
  .article-title {
    font-size: 1.4rem;
  }
}