/* CSS Reset and Base Styles */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: "Noto Sans JP", -apple-system, BlinkMacSystemFont, "Segoe UI",
    Roboto, sans-serif;
  line-height: 1.6;
  color: #222;
  background-color: #f5f5f5;
}

/* Container and Layout */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
}

/* Global Link Styles */
a {
  color: #0066cc;
  text-decoration: underline;
  transition: color 0.3s ease;
}

a:hover {
  color: #004499;
}

/* a:visited {
    color: #551a8b;
} */

/* Header Styles */
header {
  background: #222;
  color: #fff;
  padding: 0.5rem 0;  /* 1rem → 0.5rem に変更（8px相当） */
  box-shadow: 0 2px 10px rgba(0, 0, 0, 0.08);
}

.header-content {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
}

.logo {
  font-size: 1.5rem;
  font-weight: 700;
  text-decoration: none;
  color: #fff;
  line-height: 1.2;
  letter-spacing: 1px;
}

.logo:hover {
  opacity: 0.85;
}

/* Navigation Styles */
nav {
  background: #222;
  padding: 0.5rem 0;
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(6px);
}

.nav-list {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  list-style: none;
  gap: 0.5rem;
}

.nav-item a {
  display: block;
  padding: 0.8rem 1.2rem;
  color: #fff;
  text-decoration: none;
  border-radius: 5px;
  transition: background 0.2s, color 0.2s, transform 0.2s;
  font-weight: 500;
}

.nav-item a:hover {
  background-color: #333;
  color: #eee;
  transform: translateY(-2px);
}

/* Footer */
footer {
  background: #111;
  color: #bbb;
  text-align: center;
  padding: 2rem 0;
  margin-top: 3rem;
  font-size: 0.95rem;
  letter-spacing: 0.5px;
}

/* Common Content Styles */
.main-content {
  display: grid;
  grid-template-columns: 2fr 1fr;
  gap: 2rem;
  margin: 2rem 0;
}

.content-section {
  background: #fff;
  padding: 2rem;
  border-radius: 10px;
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.07);
  border-left: 4px solid #bbb;
}

.content-section h2 {
  color: #333;
  font-size: 1.5rem;
  margin-bottom: 1.5rem;
  font-weight: 600;
  border-bottom: 2px solid #e0e0e0;
  padding-bottom: 0.5rem;
}

.content-section p {
  margin-bottom: 1.2rem;
  color: #444;
  text-align: justify;
  line-height: 1.7;
}

.content-section a {
  color: #0066cc;
  text-decoration: underline;
  font-weight: 500;
  transition: color 0.3s ease;
}

.content-section a:hover {
  color: #004499;
}

.content-section a:visited {
  color: #551a8b;
}

/* Research Page Specific */
.main-layout {
  display: grid;
  grid-template-columns: 250px 1fr;
  gap: 2rem;
  margin: 2rem 0;
}

.sidebar {
  background: #fff;
  border-radius: 10px;
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.07);
  padding: 1.5rem;
  height: fit-content;
  position: sticky;
  top: 100px;
  border-left: 4px solid #888;
}

.sidebar h3 {
  color: #333;
  font-size: 1.1rem;
  margin-bottom: 1rem;
  font-weight: 600;
}

.sidebar ul {
  list-style: none;
}

.sidebar li {
  margin-bottom: 0.5rem;
}

.sidebar a {
  color: #444;
  text-decoration: none;
  padding: 0.5rem;
  display: block;
  border-radius: 5px;
  transition: all 0.3s ease;
  font-size: 0.9rem;
  line-height: 1.3;
}

.sidebar a:hover,
.sidebar a.active {
  background-color: #ededed;
  color: #111;
  transform: translateX(5px);
}

.main-content-research {
  background: #fff;
  border-radius: 10px;
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.07);
  border-left: 4px solid #bbb;
}

.page-title {
  background: linear-gradient(135deg, #222 0%, #444 100%);
  color: #fff;
  padding: 2rem;
  border-radius: 10px 10px 0 0;
  margin: 0;
  font-size: 1.8rem;
  font-weight: 600;
}

.content-wrapper {
  padding: 2rem;
}

.research-section {
  margin-bottom: 3rem;
  padding-bottom: 2rem;
  border-bottom: 2px solid #ededed;
}

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

.staff-table {
  background: #f5f5f5;
  border-radius: 8px;
  padding: 1rem;
  margin: 1rem 0;
  border: 1px solid #e0e0e0;
  float: right;
  margin-left: 2rem;
  width: 300px;
}

.staff-table table {
  width: 100%;
  border-collapse: collapse;
}

.staff-table td {
  padding: 0.5rem;
  border-bottom: 1px solid #ddd;
  font-size: 0.9rem;
}

.staff-table td:first-child {
  font-weight: 600;
  color: #333;
  width: 25%;
}

.staff-table td:nth-child(2) {
  width: 30%;
}

.staff-table td:last-child {
  color: #444;
}

.research-image {
  text-align: center;
  margin: 2rem 0;
}

.research-image img {
  max-width: 100%;
  height: auto;
  border-radius: 8px;
  box-shadow: 0 4px 15px rgba(0, 0, 0, 0.07);
  transition: transform 0.3s ease;
}

.research-image img:hover {
  transform: scale(1.02);
}

.research-image .caption {
  margin-top: 1rem;
  font-size: 0.9rem;
  color: #888;
  font-style: italic;
}

.past-research {
  background: #f5f5f5;
  border-radius: 10px;
  padding: 2rem;
  margin-top: 2rem;
}

.past-research h3 {
  color: #222;
  margin-bottom: 1.5rem;
}

.past-research h3::before {
  content: "📚";
}

.research-list {
  columns: 2;
  column-gap: 2rem;
  list-style: none;
}

.research-list li {
  margin-bottom: 0.8rem;
  padding: 0.5rem;
  background: #fff;
  border-radius: 5px;
  border-left: 3px solid #bbb;
  break-inside: avoid;
  font-size: 0.9rem;
  line-height: 1.4;
  color: #444;
}

.clearfix::after {
  content: "";
  display: table;
  clear: both;
}

/* Accessibility */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

a:focus,
button:focus {
  outline: 2px solid #888;
  outline-offset: 2px;
}

/* Animation */
@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(30px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.research-section {
  animation: fadeInUp 0.6s ease-out;
}

/* Responsive Design */
@media (max-width: 1024px) {
  .main-layout {
    grid-template-columns: 200px 1fr;
    gap: 1.5rem;
  }

  .staff-table {
    width: 250px;
  }
}

@media (max-width: 768px) {
  .container {
    padding: 0 15px;
  }

  .header-content {
    text-align: center;
  }

  .logo {
    font-size: 1.2rem;
    margin-bottom: 1rem;
  }

  .nav-list {
    flex-direction: column;
    align-items: center;
    gap: 0.2rem;
  }

  .nav-item a {
    padding: 0.6rem 1rem;
  }

  .main-content {
    grid-template-columns: 1fr;
    gap: 1.5rem;
    margin: 1.5rem 0;
  }

  .main-layout {
    grid-template-columns: 1fr;
    gap: 1rem;
  }

  .sidebar {
    position: static;
    order: 2;
    margin-top: 1rem;
  }

  .staff-table {
    float: none;
    width: 100%;
    margin: 1rem 0;
  }

  .research-list {
    columns: 1;
  }

  .page-title {
    font-size: 1.5rem;
    padding: 1.5rem;
  }

  .content-wrapper {
    padding: 1.5rem;
  }

  .content-section {
    padding: 1.5rem;
  }
}

@media (max-width: 480px) {
  .content-wrapper {
    padding: 1rem;
  }

  .research-section h3 {
    font-size: 1.2rem;
  }

  .page-title {
    font-size: 1.3rem;
    padding: 1rem;
  }

  .content-section {
    padding: 1rem;
  }
}