/* ===== 変数・リセット ===== */
:root {
  --color-primary: #1a3a5c;
  --color-primary-light: #2d5a8a;
  --color-accent: #c8a84b;
  --color-bg: #ffffff;
  --color-bg-alt: #f5f7fa;
  --color-text: #333333;
  --color-text-muted: #666666;
  --color-border: #e0e4ea;
  --font-sans: "Hiragino Sans", "Hiragino Kaku Gothic ProN", "Noto Sans JP", Meiryo, sans-serif;
  --max-width: 1100px;
  --radius: 8px;
  --shadow: 0 2px 12px rgba(0, 0, 0, 0.08);
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-sans);
  color: var(--color-text);
  background: var(--color-bg);
  line-height: 1.7;
  font-size: 16px;
}

a {
  color: var(--color-primary-light);
  text-decoration: none;
  transition: color 0.2s;
}

a:hover {
  color: var(--color-accent);
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

ul {
  list-style: none;
}

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* ===== ヘッダー ===== */
.site-header {
  background: var(--color-primary);
  color: #fff;
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: var(--shadow);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.logo {
  color: #fff;
  display: flex;
  flex-direction: column;
  line-height: 1.3;
}

.logo:hover {
  color: #fff;
  opacity: 0.9;
}

.logo-univ {
  font-size: 0.75rem;
  opacity: 0.8;
  letter-spacing: 0.05em;
}

.logo-lab {
  font-size: 1.1rem;
  font-weight: 700;
}

.site-nav ul {
  display: flex;
  gap: 0.25rem;
}

.site-nav a {
  color: rgba(255, 255, 255, 0.85);
  padding: 0.5rem 0.85rem;
  border-radius: 4px;
  font-size: 0.9rem;
  transition: background 0.2s, color 0.2s;
}

.site-nav a:hover,
.site-nav a.active {
  background: rgba(255, 255, 255, 0.15);
  color: #fff;
}

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px;
}

.nav-toggle span {
  display: block;
  width: 24px;
  height: 2px;
  background: #fff;
  border-radius: 2px;
  transition: transform 0.3s, opacity 0.3s;
}

/* ===== ヒーロー ===== */
.hero {
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-light) 100%);
  color: #fff;
  padding: 5rem 0;
}

.hero-label {
  font-size: 0.85rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  opacity: 0.75;
  margin-bottom: 0.75rem;
}

.hero h1 {
  font-size: clamp(2rem, 5vw, 3rem);
  font-weight: 700;
  margin-bottom: 1rem;
}

.hero-lead {
  font-size: 1.05rem;
  opacity: 0.9;
  max-width: 600px;
  margin-bottom: 2rem;
}

.hero-actions {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
}

/* ===== ボタン ===== */
.btn {
  display: inline-block;
  padding: 0.75rem 1.5rem;
  border-radius: var(--radius);
  font-size: 0.95rem;
  font-weight: 600;
  transition: background 0.2s, color 0.2s, border-color 0.2s;
  cursor: pointer;
  border: 2px solid transparent;
}

.btn-primary {
  background: var(--color-accent);
  color: var(--color-primary);
  border-color: var(--color-accent);
}

.btn-primary:hover {
  background: #dbb95a;
  color: var(--color-primary);
}

.btn-outline {
  background: transparent;
  color: #fff;
  border-color: rgba(255, 255, 255, 0.6);
}

.btn-outline:hover {
  background: rgba(255, 255, 255, 0.1);
  color: #fff;
}

/* ===== セクション ===== */
.section {
  padding: 4rem 0;
}

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

.section-title {
  font-size: 1.6rem;
  color: var(--color-primary);
  margin-bottom: 2rem;
  padding-bottom: 0.5rem;
  border-bottom: 3px solid var(--color-accent);
  display: inline-block;
}

.section-header {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  margin-bottom: 2rem;
  flex-wrap: wrap;
  gap: 1rem;
}

.section-header .section-title {
  margin-bottom: 0;
}

.link-more {
  font-size: 0.9rem;
  font-weight: 600;
}

/* ===== ページヘッダー（下層ページ用） ===== */
.page-header {
  background: var(--color-bg-alt);
  padding: 3rem 0 2rem;
  border-bottom: 1px solid var(--color-border);
}

.page-header h1 {
  font-size: 1.8rem;
  color: var(--color-primary);
}

.page-header p {
  color: var(--color-text-muted);
  margin-top: 0.5rem;
}

/* ===== About ===== */
.about-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 2.5rem;
  align-items: start;
}

.about-text p + p {
  margin-top: 1rem;
}

.about-highlights {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.highlight-card {
  background: var(--color-bg-alt);
  border-left: 4px solid var(--color-accent);
  padding: 1rem 1.25rem;
  border-radius: 0 var(--radius) var(--radius) 0;
}

.highlight-card h3 {
  font-size: 0.85rem;
  color: var(--color-primary);
  margin-bottom: 0.25rem;
}

.highlight-card p {
  font-size: 0.95rem;
  color: var(--color-text-muted);
}

/* ===== お知らせリスト ===== */
.news-list li {
  display: flex;
  gap: 1.5rem;
  padding: 1rem 0;
  border-bottom: 1px solid var(--color-border);
  align-items: baseline;
}

.news-list time {
  font-size: 0.85rem;
  color: var(--color-text-muted);
  white-space: nowrap;
  min-width: 90px;
}

.news-list a {
  color: var(--color-text);
  font-weight: 500;
}

.news-list a:hover {
  color: var(--color-primary-light);
}

/* ===== カード ===== */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 1.5rem;
}

.card {
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 1.5rem;
  box-shadow: var(--shadow);
  transition: transform 0.2s, box-shadow 0.2s;
}

.card:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(0, 0, 0, 0.1);
}

.card-img {
  width: 100%;
  height: 160px;
  object-fit: cover;
  border-radius: var(--radius);
  margin-bottom: 1rem;
}

.card h3 {
  color: var(--color-primary);
  margin-bottom: 0.75rem;
  font-size: 1.05rem;
}

.card p {
  color: var(--color-text-muted);
  font-size: 0.95rem;
}

/* ===== CTA ===== */
.cta-section {
  background: var(--color-primary);
  color: #fff;
  text-align: center;
}

.cta-inner h2 {
  font-size: 1.5rem;
  margin-bottom: 0.75rem;
}

.cta-inner p {
  opacity: 0.85;
  margin-bottom: 1.5rem;
}

/* ===== メンバー ===== */
.member-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 1.5rem;
}

.member-card {
  text-align: center;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 1.5rem 1rem;
  background: var(--color-bg);
}

.member-card-simple {
  text-align: left;
  padding: 1.25rem 1.25rem;
}

.member-photo {
  width: 120px;
  height: 120px;
  border-radius: 50%;
  object-fit: cover;
  object-position: center top;
  margin: 0 auto 1rem;
  display: block;
  border: 2px solid var(--color-border);
}

.member-card h3 {
  font-size: 1rem;
  color: var(--color-primary);
  margin-bottom: 0.25rem;
}

.member-role {
  font-size: 0.8rem;
  color: var(--color-accent);
  font-weight: 600;
  margin-bottom: 0.5rem;
}

.member-card p {
  font-size: 0.85rem;
  color: var(--color-text-muted);
}

.member-group-title {
  font-size: 1.1rem;
  color: var(--color-primary);
  margin: 2.5rem 0 1rem;
  padding-bottom: 0.4rem;
  border-bottom: 2px solid var(--color-border);
}

.member-group-title:first-child {
  margin-top: 0;
}

/* ===== 論文リスト ===== */
.pub-list li {
  padding: 1.25rem 0;
  border-bottom: 1px solid var(--color-border);
}

.pub-year {
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--color-primary);
  background: var(--color-bg-alt);
  padding: 0.15rem 0.5rem;
  border-radius: 4px;
  display: inline-block;
  margin-bottom: 0.4rem;
}

.pub-title {
  font-weight: 600;
  margin-bottom: 0.25rem;
}

.pub-authors {
  font-size: 0.9rem;
  color: var(--color-text-muted);
}

.pub-venue {
  font-size: 0.85rem;
  color: var(--color-text-muted);
  font-style: italic;
}

/* ===== 研究テーマ ===== */
.research-item {
  margin-bottom: 2.5rem;
  padding-bottom: 2.5rem;
  border-bottom: 1px solid var(--color-border);
}

.research-item:last-child {
  border-bottom: none;
  margin-bottom: 0;
  padding-bottom: 0;
}

.research-item h2 {
  font-size: 1.2rem;
  color: var(--color-primary);
  margin-bottom: 0.75rem;
}

.research-figure {
  margin: 0 0 1.25rem;
  max-width: 520px;
}

.research-figure img {
  width: 100%;
  border-radius: var(--radius);
  border: 1px solid var(--color-border);
  box-shadow: var(--shadow);
}

.research-figure figcaption {
  font-size: 0.85rem;
  color: var(--color-text-muted);
  margin-top: 0.5rem;
}

.research-item p {
  color: var(--color-text-muted);
  margin-bottom: 0.75rem;
}

.tag-list {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-top: 0.75rem;
}

.tag {
  background: var(--color-bg-alt);
  color: var(--color-primary);
  font-size: 0.8rem;
  padding: 0.2rem 0.6rem;
  border-radius: 20px;
  border: 1px solid var(--color-border);
}

/* ===== アクセス ===== */
.access-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 2rem;
}

.access-info h2 {
  font-size: 1.1rem;
  color: var(--color-primary);
  margin: 1.5rem 0 0.5rem;
}

.access-info h2:first-child {
  margin-top: 0;
}

.access-info p,
.access-info address {
  color: var(--color-text-muted);
  font-style: normal;
  line-height: 1.8;
}

.access-route-title {
  font-size: 0.95rem;
  color: var(--color-primary);
  margin: 1.25rem 0 0.4rem;
  font-weight: 600;
}

.access-route-list {
  list-style: disc;
  padding-left: 1.25rem;
  color: var(--color-text-muted);
  font-size: 0.9rem;
}

.access-route-list li + li {
  margin-top: 0.25rem;
}

.map-embed {
  border-radius: var(--radius);
  overflow: hidden;
  border: 1px solid var(--color-border);
  box-shadow: var(--shadow);
}

.map-embed iframe {
  display: block;
  width: 100%;
  height: 360px;
  border: 0;
}

.map-link {
  text-align: center;
  padding: 0.75rem;
  background: var(--color-bg-alt);
  font-size: 0.85rem;
  margin: 0;
}

/* ===== フッター ===== */
.site-footer {
  background: #1a1a2e;
  color: rgba(255, 255, 255, 0.7);
  padding: 3rem 0 1.5rem;
  margin-top: 0;
}

.footer-inner {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 2rem;
}

.footer-lab {
  font-size: 1.1rem;
  font-weight: 700;
  color: #fff;
  margin-bottom: 0.5rem;
}

.footer-info p {
  font-size: 0.85rem;
  margin-bottom: 0.25rem;
}

.footer-info a {
  color: rgba(255, 255, 255, 0.7);
}

.footer-info a:hover {
  color: var(--color-accent);
}

.footer-nav ul {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
}

.footer-nav a {
  color: rgba(255, 255, 255, 0.6);
  font-size: 0.85rem;
}

.footer-nav a:hover {
  color: #fff;
}

.copyright {
  grid-column: 1 / -1;
  font-size: 0.8rem;
  opacity: 0.5;
  margin-top: 1rem;
  padding-top: 1rem;
  border-top: 1px solid rgba(255, 255, 255, 0.1);
}

/* ===== レスポンシブ ===== */
@media (max-width: 768px) {
  .nav-toggle {
    display: flex;
  }

  .site-nav {
    display: none;
    position: absolute;
    top: 64px;
    left: 0;
    right: 0;
    background: var(--color-primary);
    padding: 1rem;
    box-shadow: var(--shadow);
  }

  .site-nav.open {
    display: block;
  }

  .site-nav ul {
    flex-direction: column;
    gap: 0;
  }

  .site-nav a {
    display: block;
    padding: 0.75rem 1rem;
  }

  .about-grid,
  .access-grid {
    grid-template-columns: 1fr;
  }

  .footer-inner {
    grid-template-columns: 1fr;
  }

  .hero {
    padding: 3rem 0;
  }

  .section {
    padding: 2.5rem 0;
  }
}