/* =============================================
   KAMEI LAB — Main Stylesheet
   Inspired by Digital Nature Group (tsukuba)
   ============================================= */

/* ---------- CSS Variables ---------- */
:root {
  --color-bg: #ffffff;
  --color-bg-alt: #f7f7f7;
  --color-text: #111111;
  --color-text-light: #666666;
  --color-text-lighter: #999999;
  --color-accent: #1a1a1a;
  --color-border: #e0e0e0;
  --color-tag: #111111;
  --color-tag-award: #8b0000;

  --font-sans: 'Inter', 'Noto Sans JP', sans-serif;
  --font-jp: 'Noto Sans JP', sans-serif;

  --max-width: 1100px;
  --header-height: 64px;

  --transition: 0.25s ease;
  --shadow-sm: 0 1px 4px rgba(0,0,0,0.08);
  --shadow-md: 0 4px 16px rgba(0,0,0,0.10);
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: var(--font-sans);
  color: var(--color-text);
  background: var(--color-bg);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

img, svg {
  display: block;
  max-width: 100%;
}

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

ul, ol {
  list-style: none;
}

/* ---------- Utility ---------- */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

/* ---------- Header ---------- */
#site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background: rgba(255,255,255,0.96);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--color-border);
  height: var(--header-height);
}

.header-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

.logo a {
  display: flex;
  flex-direction: column;
  line-height: 1.2;
}

.logo-main {
  font-family: var(--font-sans);
  font-weight: 700;
  font-size: 1.1rem;
  letter-spacing: 0.08em;
  color: var(--color-text);
}

.logo-sub {
  font-family: var(--font-jp);
  font-size: 0.68rem;
  color: var(--color-text-light);
  letter-spacing: 0.04em;
  font-weight: 400;
}

#global-nav ul {
  display: flex;
  gap: 32px;
}

#global-nav a {
  font-size: 0.78rem;
  font-weight: 500;
  letter-spacing: 0.1em;
  color: var(--color-text);
  position: relative;
  padding-bottom: 2px;
  transition: color var(--transition);
}

#global-nav a::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 1px;
  background: var(--color-text);
  transition: width var(--transition);
}

#global-nav a:hover::after {
  width: 100%;
}

/* Hamburger */
.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: space-between;
  width: 26px;
  height: 18px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0;
  z-index: 1100;
}

.nav-toggle span {
  display: block;
  width: 100%;
  height: 2px;
  background: var(--color-text);
  border-radius: 2px;
  transition: transform var(--transition), opacity var(--transition);
}

.nav-toggle.open span:nth-child(1) {
  transform: translateY(8px) rotate(45deg);
}
.nav-toggle.open span:nth-child(2) {
  opacity: 0;
}
.nav-toggle.open span:nth-child(3) {
  transform: translateY(-8px) rotate(-45deg);
}

/* ---------- Hero ---------- */
.hero {
  position: relative;
  height: 100vh;
  min-height: 560px;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
  background: #0a0a0a;
}

.hero-bg {
  position: absolute;
  inset: 0;
  background:
    linear-gradient(135deg, #0a0a0a 0%, #1a1a2e 40%, #16213e 70%, #0f3460 100%);
  opacity: 0.95;
}

/* Animated grid overlay */
.hero-bg::after {
  content: '';
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(255,255,255,0.03) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255,255,255,0.03) 1px, transparent 1px);
  background-size: 60px 60px;
}

.hero-content {
  position: relative;
  z-index: 1;
  text-align: center;
  color: #fff;
  padding: 0 24px;
}

.hero-label {
  font-size: 0.75rem;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: rgba(255,255,255,0.5);
  margin-bottom: 16px;
  font-weight: 300;
}

.hero-title {
  font-family: var(--font-jp);
  font-size: clamp(2.8rem, 8vw, 6rem);
  font-weight: 700;
  letter-spacing: 0.05em;
  line-height: 1.1;
  margin-bottom: 20px;
  color: #fff;
}

.hero-subtitle {
  font-family: var(--font-jp);
  font-size: clamp(0.9rem, 2.5vw, 1.15rem);
  color: rgba(255,255,255,0.65);
  line-height: 1.8;
  margin-bottom: 40px;
  font-weight: 300;
}

.hero-btn {
  display: inline-block;
  border: 1px solid rgba(255,255,255,0.5);
  color: #fff;
  padding: 12px 36px;
  font-size: 0.78rem;
  letter-spacing: 0.2em;
  font-weight: 500;
  transition: background var(--transition), border-color var(--transition);
}

.hero-btn:hover {
  background: rgba(255,255,255,0.12);
  border-color: #fff;
}

.hero-scroll-indicator {
  position: absolute;
  bottom: 32px;
  left: 50%;
  transform: translateX(-50%);
  z-index: 1;
}

.hero-scroll-indicator span {
  display: block;
  width: 1px;
  height: 56px;
  background: linear-gradient(to bottom, transparent, rgba(255,255,255,0.5));
  margin: 0 auto;
  animation: scrollLine 1.8s ease-in-out infinite;
}

@keyframes scrollLine {
  0% { transform: scaleY(0); transform-origin: top; }
  50% { transform: scaleY(1); transform-origin: top; }
  51% { transform: scaleY(1); transform-origin: bottom; }
  100% { transform: scaleY(0); transform-origin: bottom; }
}

/* ---------- Sections ---------- */
.section {
  padding: 100px 0;
}

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

.section-title {
  font-size: 0.72rem;
  letter-spacing: 0.25em;
  font-weight: 600;
  color: var(--color-text-lighter);
  text-transform: uppercase;
  margin-bottom: 48px;
  position: relative;
  padding-bottom: 16px;
}

.section-title::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 32px;
  height: 1px;
  background: var(--color-text);
}

.section-lead {
  font-family: var(--font-jp);
  font-size: 1rem;
  color: var(--color-text-light);
  max-width: 640px;
  margin-bottom: 56px;
  line-height: 1.8;
}

/* ---------- About ---------- */
.about-grid {
  display: grid;
  grid-template-columns: 280px 1fr;
  gap: 64px;
  align-items: start;
}

.photo-placeholder {
  aspect-ratio: 3/4;
  background: var(--color-bg-alt);
  border: 1px solid var(--color-border);
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
}

.photo-placeholder-inner {
  text-align: center;
  color: var(--color-text-lighter);
}

.photo-placeholder-inner svg {
  width: 80px;
  height: 80px;
  margin: 0 auto 12px;
}

.photo-placeholder-inner p {
  font-size: 0.8rem;
  letter-spacing: 0.05em;
}

.about-name {
  font-family: var(--font-jp);
  font-size: 1.8rem;
  font-weight: 700;
  margin-bottom: 8px;
  display: flex;
  align-items: baseline;
  gap: 16px;
  flex-wrap: wrap;
}

.about-name-en {
  font-family: var(--font-sans);
  font-size: 0.9rem;
  font-weight: 400;
  color: var(--color-text-light);
  letter-spacing: 0.05em;
}

.about-affiliation {
  font-family: var(--font-jp);
  font-size: 0.9rem;
  color: var(--color-text-light);
  margin-bottom: 28px;
  line-height: 1.7;
}

.about-desc {
  font-family: var(--font-jp);
  font-size: 0.97rem;
  line-height: 1.9;
  color: var(--color-text);
  margin-bottom: 28px;
}

.about-desc p + p {
  margin-top: 16px;
}

.about-badges {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.badge {
  display: inline-block;
  border: 1px solid var(--color-border);
  padding: 4px 12px;
  font-size: 0.75rem;
  letter-spacing: 0.04em;
  color: var(--color-text-light);
  font-family: var(--font-jp);
}

/* ---------- Lab Cards ---------- */
.lab-cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 32px;
}

.lab-card {
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  padding: 32px;
  transition: box-shadow var(--transition), transform var(--transition);
}

.lab-card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
}

.lab-card-header {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 16px;
}

.lab-card-tag {
  display: inline-block;
  background: var(--color-tag);
  color: #fff;
  font-size: 0.68rem;
  letter-spacing: 0.1em;
  padding: 3px 10px;
  font-weight: 600;
}

.lab-card-tag.award {
  background: var(--color-tag-award);
}

.lab-card-title {
  font-family: var(--font-jp);
  font-size: 1.05rem;
  font-weight: 700;
}

.lab-card-body {
  font-family: var(--font-jp);
  font-size: 0.9rem;
  color: var(--color-text-light);
  line-height: 1.8;
  margin-bottom: 20px;
}

.lab-card-footer {
  border-top: 1px solid var(--color-border);
  padding-top: 12px;
}

.lab-card-category {
  font-size: 0.72rem;
  letter-spacing: 0.1em;
  color: var(--color-text-lighter);
  text-transform: uppercase;
}

/* ---------- Research ---------- */
.research-tabs {
  display: flex;
  gap: 0;
  border-bottom: 1px solid var(--color-border);
  margin-bottom: 48px;
}

.tab-btn {
  background: none;
  border: none;
  padding: 12px 28px;
  font-family: var(--font-jp);
  font-size: 0.88rem;
  font-weight: 500;
  color: var(--color-text-light);
  cursor: pointer;
  position: relative;
  transition: color var(--transition);
  letter-spacing: 0.04em;
}

.tab-btn::after {
  content: '';
  position: absolute;
  bottom: -1px;
  left: 0;
  right: 0;
  height: 2px;
  background: var(--color-text);
  transform: scaleX(0);
  transition: transform var(--transition);
}

.tab-btn.active {
  color: var(--color-text);
}

.tab-btn.active::after {
  transform: scaleX(1);
}

.tab-content {
  display: none;
}

.tab-content.active {
  display: block;
}

.research-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 1px;
  background: var(--color-border);
  border: 1px solid var(--color-border);
}

.research-card {
  background: var(--color-bg);
  padding: 32px;
  display: flex;
  flex-direction: column;
  gap: 16px;
  transition: background var(--transition);
}

.research-card:hover {
  background: #fafafa;
}

.research-card-num {
  font-family: var(--font-sans);
  font-size: 0.68rem;
  font-weight: 600;
  letter-spacing: 0.15em;
  color: var(--color-text-lighter);
}

.research-card-body h3 {
  font-family: var(--font-jp);
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: 12px;
  line-height: 1.5;
}

.research-card-body p {
  font-family: var(--font-jp);
  font-size: 0.87rem;
  color: var(--color-text-light);
  line-height: 1.8;
  margin-bottom: 16px;
}

.research-link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.78rem;
  font-weight: 500;
  letter-spacing: 0.06em;
  color: var(--color-text);
  border-bottom: 1px solid var(--color-border);
  padding-bottom: 2px;
  transition: border-color var(--transition), color var(--transition);
  width: fit-content;
}

.research-link svg {
  width: 14px;
  height: 14px;
  flex-shrink: 0;
}

.research-link:hover {
  border-color: var(--color-text);
  color: var(--color-text);
}

/* ---------- News ---------- */
.news-list {
  display: flex;
  flex-direction: column;
  gap: 0;
  border-top: 1px solid var(--color-border);
}

.news-item {
  display: grid;
  grid-template-columns: 120px 1fr;
  gap: 32px;
  padding: 32px 0;
  border-bottom: 1px solid var(--color-border);
  align-items: start;
  transition: background var(--transition);
}

.news-item:hover {
  background: rgba(0,0,0,0.01);
}

.news-date {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.news-year {
  font-size: 0.68rem;
  letter-spacing: 0.1em;
  color: var(--color-text-lighter);
  font-weight: 400;
}

.news-md {
  font-size: 0.88rem;
  font-weight: 600;
  letter-spacing: 0.05em;
  color: var(--color-text-light);
}

.news-tag {
  display: inline-block;
  border: 1px solid var(--color-border);
  font-size: 0.68rem;
  letter-spacing: 0.08em;
  padding: 2px 8px;
  color: var(--color-text-light);
  margin-bottom: 8px;
  font-family: var(--font-jp);
}

.news-title {
  font-family: var(--font-jp);
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: 8px;
  line-height: 1.5;
}

.news-excerpt {
  font-family: var(--font-jp);
  font-size: 0.87rem;
  color: var(--color-text-light);
  line-height: 1.7;
}

/* ---------- Contact ---------- */
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 64px;
  align-items: start;
}

.contact-info h3 {
  font-family: var(--font-jp);
  font-size: 1.2rem;
  font-weight: 700;
  margin-bottom: 24px;
}

.contact-table {
  width: 100%;
  border-collapse: collapse;
  margin-bottom: 24px;
}

.contact-table th,
.contact-table td {
  padding: 12px 0;
  border-bottom: 1px solid var(--color-border);
  font-family: var(--font-jp);
  font-size: 0.9rem;
  vertical-align: top;
  text-align: left;
}

.contact-table th {
  width: 80px;
  color: var(--color-text-light);
  font-weight: 500;
  white-space: nowrap;
}

.contact-table td {
  line-height: 1.7;
}

.contact-table a {
  border-bottom: 1px solid var(--color-border);
  transition: border-color var(--transition);
}

.contact-table a:hover {
  border-color: var(--color-text);
}

.contact-note {
  font-family: var(--font-jp);
  font-size: 0.85rem;
  color: var(--color-text-light);
  line-height: 1.7;
}

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

.map-embed iframe {
  display: block;
}

/* ---------- Footer ---------- */
#site-footer {
  background: var(--color-text);
  color: #fff;
  padding: 56px 0 32px;
}

.footer-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
  display: flex;
  flex-direction: column;
  gap: 32px;
}

.footer-logo {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.footer-logo .logo-main {
  color: #fff;
  font-size: 1.1rem;
}

.footer-logo .logo-sub {
  color: rgba(255,255,255,0.5);
  font-size: 0.68rem;
}

.footer-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 24px;
}

.footer-nav a {
  font-size: 0.75rem;
  letter-spacing: 0.12em;
  color: rgba(255,255,255,0.6);
  transition: color var(--transition);
}

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

.footer-copy {
  font-size: 0.72rem;
  color: rgba(255,255,255,0.35);
  letter-spacing: 0.04em;
  border-top: 1px solid rgba(255,255,255,0.1);
  padding-top: 24px;
}

/* =============================================
   RESPONSIVE
   ============================================= */

@media (max-width: 900px) {
  .about-grid {
    grid-template-columns: 1fr;
    gap: 40px;
  }

  .photo-placeholder {
    max-width: 240px;
    aspect-ratio: 1/1;
  }

  .contact-grid {
    grid-template-columns: 1fr;
    gap: 40px;
  }
}

@media (max-width: 768px) {
  :root {
    --header-height: 56px;
  }

  /* Mobile Nav */
  .nav-toggle {
    display: flex;
  }

  #global-nav {
    position: fixed;
    top: var(--header-height);
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(255,255,255,0.98);
    backdrop-filter: blur(12px);
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    pointer-events: none;
    transition: opacity var(--transition);
    z-index: 999;
  }

  #global-nav.open {
    opacity: 1;
    pointer-events: auto;
  }

  #global-nav ul {
    flex-direction: column;
    align-items: center;
    gap: 40px;
  }

  #global-nav a {
    font-size: 1.1rem;
    letter-spacing: 0.15em;
  }

  .section {
    padding: 72px 0;
  }

  .section-title {
    margin-bottom: 36px;
  }

  .hero-title {
    font-size: clamp(2.4rem, 12vw, 4rem);
  }

  .research-grid {
    grid-template-columns: 1fr;
  }

  .news-item {
    grid-template-columns: 1fr;
    gap: 12px;
  }

  .news-date {
    flex-direction: row;
    align-items: center;
    gap: 8px;
  }

  .tab-btn {
    padding: 10px 16px;
    font-size: 0.82rem;
  }

  .lab-cards {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 480px) {
  .container {
    padding: 0 16px;
  }

  .hero-content {
    padding: 0 16px;
  }

  .section {
    padding: 56px 0;
  }

  .research-card {
    padding: 24px;
  }

  .lab-card {
    padding: 24px;
  }
}

/* ---------- Scroll animation ---------- */
.fade-in {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.fade-in.visible {
  opacity: 1;
  transform: translateY(0);
}