/* ============================================================
   Uritani Laboratory - Main Stylesheet (task4 design polish)
   Django移行時: {% load static %} → {% static 'css/style.css' %}
   ============================================================ */

/* --- Custom Properties --- */
:root {
  /* Brand colours */
  --color-primary: #1e4d6b;
  --color-primary-mid: #2c6e9b;
  --color-accent: #8fa8b5;
  /* 名古屋大学 blue-grey */
  --color-accent-light: #c4d5de;
  --color-accent-dark: #6b8a99;

  /* Backgrounds */
  --color-bg: #f2f5f7;
  --color-white: #ffffff;
  --color-surface-alt: #eef3f6;

  /* Text */
  --color-text: #2d3a42;
  --color-text-mid: #4a5d6a;
  --color-text-light: #7a8f9c;

  /* UI */
  --color-border: #d0dde5;
  --color-footer-bg: #1a2e3a;
  --color-shadow: rgba(30, 77, 107, 0.08);
  --color-shadow-hover: rgba(30, 77, 107, 0.18);

  /* Typography */
  --font-main: 'Noto Sans JP', 'Hiragino Kaku Gothic ProN', 'Meiryo', sans-serif;
  --font-latin: 'Lato', 'Arial', sans-serif;

  /* Layout */
  --max-width: 1100px;
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;

  /* Motion */
  --transition: 0.22s ease;
  --transition-slow: 0.40s ease;
}

/* ============================================================
   RESET & BASE
   ============================================================ */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

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

body {
  font-family: var(--font-main);
  line-height: 1.85;
  color: var(--color-text);
  background-color: var(--color-bg);
  -webkit-font-smoothing: antialiased;
}

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

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

a:hover {
  color: var(--color-primary-mid);
}

ul {
  list-style: none;
}

/* ============================================================
   LAYOUT WRAPPER
   ============================================================ */
.site-wrapper {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 28px;
  width: 100%;
}

/* ============================================================
   HEADER
   ============================================================ */
.site-header {
  background-color: var(--color-white);
  border-bottom: 3px solid var(--color-accent);
  position: sticky;
  top: 0;
  z-index: 200;
  box-shadow: 0 2px 12px var(--color-shadow);
  transition: box-shadow var(--transition);
}

.site-header:hover {
  box-shadow: 0 4px 20px var(--color-shadow-hover);
}

.header-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 18px 28px 0;
  position: relative;
}

.site-title {
  font-size: 1.85rem;
  font-weight: 700;
  color: var(--color-primary);
  letter-spacing: 0.03em;
  line-height: 1.2;
}

.site-title a {
  color: inherit;
  text-decoration: none;
  transition: opacity 0.2s ease;
}

.site-title a:hover,
.site-title a:focus {
  opacity: 0.7;
  text-decoration: none;
}

/* tour.html を埋め込む iframe — スマホでは縦長レイアウトに対応 */
.tour-iframe {
  width: 100%;
  aspect-ratio: 1120 / 780;
  border: none;
  overflow: hidden;
  display: block;
}

@media (max-width: 640px) {
  .tour-iframe {
    /* モバイル時は tour.html のステージが縦長になる（マップ + 情報バー） */
    aspect-ratio: 1120 / 1050;
  }
}

@media (max-width: 400px) {
  .tour-iframe {
    aspect-ratio: 1120 / 1100;
  }
}

.site-subtitle {
  font-size: 0.76rem;
  color: var(--color-text-light);
  margin-top: 4px;
  line-height: 1.7;
  letter-spacing: 0.01em;
}

/* --- Language Switch --- */
.lang-switch {
  position: absolute;
  top: 20px;
  right: 28px;
  display: flex;
  align-items: center;
  gap: 4px;
  font-size: 0.78rem;
}

.lang-switch span {
  color: var(--color-border);
}

.lang-btn {
  padding: 3px 10px;
  border: 1.5px solid var(--color-border);
  border-radius: var(--radius-sm);
  color: var(--color-text-light);
  font-weight: 700;
  font-size: 0.76rem;
  letter-spacing: 0.06em;
  text-decoration: none;
  transition: background var(--transition), color var(--transition), border-color var(--transition);
}

.lang-btn:hover,
.lang-btn.active {
  background-color: var(--color-primary);
  color: var(--color-white);
  border-color: var(--color-primary);
}

/* --- Navigation --- */
.site-nav {
  margin-top: 14px;
}

.site-nav ul {
  display: flex;
  gap: 0;
  border-top: 1px solid var(--color-border);
}

.site-nav li a {
  display: block;
  padding: 11px 20px;
  font-size: 0.86rem;
  font-weight: 500;
  color: var(--color-text-mid);
  letter-spacing: 0.04em;
  position: relative;
  transition: color var(--transition), background var(--transition);
}

/* underline indicator */
.site-nav li a::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 0;
  height: 3px;
  background-color: var(--color-primary);
  transition: width var(--transition);
}

.site-nav li a:hover::after,
.site-nav li a.active::after {
  width: 100%;
}

.site-nav li a:hover {
  color: var(--color-primary);
  background-color: rgba(143, 168, 181, 0.08);
}

.site-nav li a.active {
  color: var(--color-primary);
  font-weight: 700;
}

/* Hamburger button (mobile) */
.nav-toggle {
  display: none;
  background: none;
  border: 2px solid var(--color-accent);
  border-radius: var(--radius-sm);
  cursor: pointer;
  padding: 7px 9px;
  position: absolute;
  top: 16px;
  right: 20px;
  transition: background var(--transition), border-color var(--transition);
}

.nav-toggle:hover {
  background-color: var(--color-accent);
}

.nav-toggle span {
  display: block;
  width: 22px;
  height: 2px;
  background-color: var(--color-primary);
  margin: 4px 0;
  transition: transform var(--transition), opacity var(--transition), background var(--transition);
  border-radius: 2px;
}

.nav-toggle:hover span {
  background-color: var(--color-white);
}

/* ============================================================
   HERO / KEY VISUAL
   ============================================================ */
.keyvisual {
  width: 100%;
  max-height: 460px;
  overflow: hidden;
  position: relative;
  background-color: var(--color-primary);
}

.keyvisual img {
  width: 100%;
  height: 460px;
  object-fit: cover;
  object-position: center;
  opacity: 0.9;
}

.keyvisual-placeholder {
  width: 100%;
  height: 380px;
  background: linear-gradient(135deg,
      var(--color-primary) 0%,
      var(--color-primary-mid) 45%,
      var(--color-accent) 100%);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  color: rgba(255, 255, 255, 0.85);
  font-size: 1rem;
  letter-spacing: 0.12em;
  gap: 12px;
  position: relative;
  overflow: hidden;
}

.keyvisual-placeholder::before {
  content: '';
  position: absolute;
  inset: 0;
  background: repeating-linear-gradient(45deg,
      transparent,
      transparent 40px,
      rgba(255, 255, 255, 0.03) 40px,
      rgba(255, 255, 255, 0.03) 41px);
}

/* ============================================================
   MAIN CONTENT
   ============================================================ */
.site-main {
  flex: 1;
  padding: 52px 0 72px;
}

/* --- Page Header (inner pages) --- */
.page-header {
  width: 100vw;
  position: relative;
  left: 50%;
  right: 50%;
  margin-left: -50vw;
  margin-right: -50vw;

  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-mid) 100%);
  color: var(--color-white);
  text-align: center;
  padding: 60px 20px;
  border-left: none;
  border-radius: 0;
  margin-bottom: 48px;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

.page-header h1 {
  font-size: 2.5rem;
  color: var(--color-white);
  margin-bottom: 12px;
  font-weight: 700;
  letter-spacing: 0.08em;
  border-bottom: none;
  padding-bottom: 0;
  display: block;
  text-shadow: 0 2px 6px rgba(0, 0, 0, 0.3);
}

.page-header-sub {
  font-size: 1.1rem;
  color: rgba(255, 255, 255, 0.9);
  letter-spacing: 0.05em;
}

/* --- Section Heading --- */
.section-title {
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--color-primary);
  margin-bottom: 28px;
  padding-bottom: 12px;
  border-bottom: 2px solid var(--color-accent);
  display: flex;
  align-items: center;
  gap: 10px;
}

.section-title::before {
  content: '';
  display: inline-block;
  width: 6px;
  height: 1.35rem;
  background-color: var(--color-accent);
  border-radius: 2px;
  flex-shrink: 0;
}

/* ============================================================
   HOME PAGE
   ============================================================ */
.welcome-section {
  background-color: var(--color-white);
  border-radius: var(--radius-lg);
  padding: 44px 48px;
  margin-bottom: 36px;
  box-shadow: 0 2px 10px var(--color-shadow);
  border-top: 4px solid var(--color-accent);
}

.welcome-section h2 {
  font-size: 1.5rem;
  color: var(--color-primary);
  margin-bottom: 22px;
  padding-bottom: 14px;
  border-bottom: 2px solid var(--color-accent-light);
  letter-spacing: 0.01em;
}

.welcome-section p {
  margin-bottom: 18px;
  line-height: 1.95;
  color: var(--color-text);
}

.welcome-figure {
  text-align: center;
  margin: 36px 0;
}

.welcome-figure img {
  max-width: 68%;
  margin: 0 auto;
  border-radius: var(--radius-md);
  box-shadow: 0 4px 16px var(--color-shadow);
}

.cta-box {
  background: linear-gradient(135deg,
      var(--color-surface-alt) 0%,
      rgba(196, 213, 222, 0.25) 100%);
  border: 1px solid var(--color-accent-light);
  border-radius: var(--radius-md);
  padding: 32px 36px;
  margin-top: 36px;
}

.cta-box p {
  margin-bottom: 10px;
  line-height: 1.85;
}

.cta-btn {
  display: inline-block;
  margin-top: 18px;
  padding: 13px 36px;
  background-color: var(--color-primary);
  color: var(--color-white);
  border-radius: 30px;
  font-weight: 600;
  font-size: 0.93rem;
  letter-spacing: 0.04em;
  box-shadow: 0 3px 10px rgba(30, 77, 107, 0.25);
  transition: background var(--transition), box-shadow var(--transition), transform var(--transition);
}

.cta-btn:hover {
  background-color: var(--color-primary-mid);
  color: var(--color-white);
  box-shadow: 0 6px 18px rgba(30, 77, 107, 0.30);
  transform: translateY(-2px);
}

/* ============================================================
   NEWS PAGE
   ============================================================ */
.news-list {
  background-color: var(--color-white);
  border-radius: var(--radius-md);
  box-shadow: 0 2px 10px var(--color-shadow);
  overflow: hidden;
}

/* news-item は <details> 要素 (expandable) または <div> (flat) どちらでも対応 */
.news-item {
  border-bottom: 1px solid var(--color-border);
  transition: background var(--transition);
}

.news-item:last-child {
  border-bottom: none;
}

/* details の open 状態 / div や a の hover */
.news-item:hover,
details.news-item[open] {
  background-color: var(--color-surface-alt);
}

a.news-item {
  color: inherit;
  text-decoration: none;
}

a.news-item:hover .news-text {
  color: var(--color-primary-mid);
  text-decoration: underline;
}

/* <summary> 内レイアウト（expandable 版） */
details.news-item {
  display: block;
}

.news-summary {
  display: flex;
  gap: 20px;
  padding: 20px 48px 20px 32px;
  align-items: flex-start;
  cursor: pointer;
  list-style: none;
  transition: background var(--transition);
  position: relative;
}

.news-summary::-webkit-details-marker {
  display: none;
}

.news-summary::marker {
  display: none;
}

/* Custom expand/collapse indicator for news */
details.news-item summary::after {
  content: "+";
  position: absolute;
  right: 24px;
  top: 50%;
  transform: translateY(-50%);
  font-size: 1.4rem;
  font-weight: 500;
  color: var(--color-text-light);
  transition: transform var(--transition);
}

details.news-item[open] summary::after {
  content: "−";
}

/* flat 版 (.news-item が <div>) の内部レイアウト */
.news-item>.news-date,
.news-item>.news-text {
  /* flat 版: news-item 自体を flex にする */
}

.news-item:not(details) {
  display: flex;
  gap: 20px;
  padding: 20px 32px;
  align-items: flex-start;
}

/* expandable: 詳細コンテンツ */
.news-content {
  padding: 0 32px 20px;
  font-size: 0.95rem;
  line-height: 1.8;
  color: var(--color-text-mid);
  border-top: 1px solid var(--color-border);
}

.news-content p {
  margin-bottom: 8px;
}

.news-content p:last-child {
  margin-bottom: 0;
}

.news-date {
  font-size: 0.82rem;
  color: var(--color-text-light);
  white-space: nowrap;
  min-width: 90px;
  padding-top: 3px;
}

.news-tag {
  display: inline-block;
  font-size: 0.70rem;
  padding: 2px 10px;
  border-radius: 20px;
  font-weight: 700;
  white-space: nowrap;
  margin-right: 8px;
  letter-spacing: 0.04em;
}

.news-tag.tag-news {
  background: #d8eef4;
  color: #0c5460;
}

.news-tag.tag-event {
  background: #d4edda;
  color: #155724;
}

.news-tag.tag-recruit {
  background: #fff3cd;
  color: #856404;
}

.news-tag.tag-other {
  background: #e2e3e5;
  color: #383d41;
}

.news-text {
  flex: 1;
  font-size: 0.95rem;
  line-height: 1.75;
}

/* ============================================================
   STUDY PAGE
   ============================================================ */
.study-grid {
  display: flex;
  flex-direction: column;
  gap: 32px;
}

.study-card {
  background-color: var(--color-white);
  border-radius: var(--radius-md);
  overflow: hidden;
  box-shadow: 0 2px 8px var(--color-shadow);
  transition: transform var(--transition), box-shadow var(--transition);
  display: grid;
  grid-template-columns: 1fr 1fr;
  grid-template-rows: auto 1fr;
}

.study-card:hover {
  transform: translateY(-3px);
  box-shadow: 0 8px 24px var(--color-shadow-hover);
}

.study-card-header {
  background: linear-gradient(135deg,
      var(--color-primary) 0%,
      var(--color-primary-mid) 100%);
  color: var(--color-white);
  padding: 18px 22px;
  grid-column: 1 / -1;
}

.study-card-number {
  font-size: 1rem;
  opacity: 0.65;
  margin-bottom: 5px;
  letter-spacing: 0.08em;
}

.study-card-title {
  font-size: 1.5rem;
  font-weight: 700;
  line-height: 1.5;
}

.study-card-body {
  padding: 24px 32px;
  font-size: 1.2rem;
  color: var(--color-text-mid);
  line-height: 2;
  display: flex;
  align-items: center;
}

.study-card-figure {
  background-color: var(--color-surface-alt);
  border-left: 1px solid var(--color-border);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 0;
  color: var(--color-text-light);
  font-size: 0.82rem;
  text-align: center;
  line-height: 1.7;
  width: 100%;
}

.study-card-figure img {
  width: 100%;
  height: auto;
  object-fit: cover;
  display: block;
}

/* ============================================================
   MEMBER PAGE
   ============================================================ */
.member-section {
  margin-bottom: 48px;
}

.member-role-title {
  font-size: 0.95rem;
  font-weight: 700;
  margin-bottom: 20px;
  padding: 10px 20px;
  background: linear-gradient(90deg,
      var(--color-accent) 0%,
      var(--color-accent-dark) 100%);
  color: var(--color-white);
  border-radius: var(--radius-sm);
  letter-spacing: 0.05em;
  box-shadow: 0 2px 6px rgba(143, 168, 181, 0.35);
}

/* Faculty: 横並び大カード */
.faculty-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 22px;
}

.faculty-card {
  background-color: var(--color-white);
  border-radius: var(--radius-md);
  padding: 36px 28px;
  text-align: center;
  box-shadow: 0 2px 8px var(--color-shadow);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  aspect-ratio: 1 / 1;
  transition: transform var(--transition), box-shadow var(--transition), border-top-color var(--transition);
  border-top: 3px solid var(--color-accent-light);
}

.faculty-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 8px 20px var(--color-shadow-hover);
  border-top-color: var(--color-accent);
}

.faculty-card .member-avatar {
  width: 108px;
  height: 108px;
  font-size: 2.2rem;
  margin-bottom: 16px;
}

.faculty-card .member-name {
  font-size: 1.15rem;
  margin-bottom: 5px;
}

.faculty-card .member-name-en {
  font-size: 0.88rem;
  margin-bottom: 10px;
}

.faculty-card .member-info {
  font-size: 0.9rem;
}

/* Students */
.member-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 22px;
}

.member-card {
  background-color: var(--color-white);
  border-radius: var(--radius-md);
  padding: 28px 22px;
  text-align: center;
  box-shadow: 0 2px 8px var(--color-shadow);
  transition: transform var(--transition), box-shadow var(--transition), border-top-color var(--transition);
  border-top: 3px solid var(--color-accent-light);
  aspect-ratio: 1 / 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
}

.member-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 8px 20px var(--color-shadow-hover);
  border-top-color: var(--color-accent);
}

.member-avatar {
  width: 84px;
  height: 84px;
  border-radius: 50%;
  background: linear-gradient(135deg,
      var(--color-primary) 0%,
      var(--color-accent) 100%);
  margin: 0 auto 14px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-size: 1.7rem;
  box-shadow: 0 3px 10px rgba(143, 168, 181, 0.40);
}

.member-name {
  font-weight: 700;
  font-size: 1rem;
  margin-bottom: 4px;
  color: var(--color-text);
}

.member-name a {
  color: var(--color-text);
}

.member-name a:hover {
  color: var(--color-primary-mid);
}

.member-name-en {
  font-size: 0.78rem;
  color: var(--color-text-light);
  margin-bottom: 10px;
}

.member-info {
  font-size: 0.80rem;
  color: var(--color-text-light);
  line-height: 1.7;
}

/* ============================================================
   PRESENTATION PAGE
   ============================================================ */
.publication-year {
  margin-bottom: 44px;
}

.year-heading {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--color-primary);
  margin-bottom: 18px;
  display: flex;
  align-items: center;
  gap: 14px;
}

.year-heading::after {
  content: '';
  flex: 1;
  height: 1px;
  background: linear-gradient(90deg, var(--color-border) 0%, transparent 100%);
}

.publication-list {
  background-color: var(--color-white);
  border-radius: var(--radius-md);
  overflow: hidden;
  box-shadow: 0 2px 8px var(--color-shadow);
}

.publication-entry {
  padding: 18px 28px;
  border-bottom: 1px solid var(--color-border);
  font-size: 0.93rem;
  line-height: 1.85;
  transition: background var(--transition);
}

.publication-entry:hover {
  background-color: var(--color-surface-alt);
}

.publication-entry:last-child {
  border-bottom: none;
}

.publication-entry .entry-type {
  display: inline-block;
  font-size: 0.70rem;
  padding: 2px 9px;
  border-radius: var(--radius-sm);
  margin-right: 10px;
  font-weight: 700;
  letter-spacing: 0.04em;
  vertical-align: middle;
}

.entry-type.journal {
  background: #d8eef4;
  color: #0c5460;
}

.entry-type.conference {
  background: #d4edda;
  color: #155724;
}

.entry-type.invited {
  background: #ffe5d0;
  color: #7b3e00;
}

/* 絞り込みフィルターバー */
.filter-bar {
  background-color: var(--color-white);
  border-radius: var(--radius-md);
  padding: 18px 28px;
  margin-bottom: 32px;
  box-shadow: 0 2px 8px var(--color-shadow);
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  align-items: center;
}

.filter-bar-label {
  font-weight: 600;
  font-size: 0.88rem;
  color: var(--color-text-mid);
  margin-right: 4px;
}

.filter-btn {
  display: inline-block;
  font-size: 0.75rem;
  padding: 4px 14px;
  border-radius: 20px;
  font-weight: 700;
  letter-spacing: 0.04em;
  cursor: pointer;
  transition: opacity var(--transition), transform var(--transition);
  text-decoration: none;
}

.filter-btn:hover {
  opacity: 0.80;
  transform: translateY(-1px);
}

/* ============================================================
   ACCESS PAGE
   ============================================================ */
.access-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 36px;
  margin-bottom: 36px;
}

.access-info {
  background-color: var(--color-white);
  border-radius: var(--radius-md);
  padding: 36px;
  box-shadow: 0 2px 8px var(--color-shadow);
}

.access-info h3 {
  font-size: 1rem;
  font-weight: 700;
  color: var(--color-primary);
  margin-bottom: 18px;
  padding-bottom: 10px;
  border-bottom: 2px solid var(--color-accent-light);
}

.access-info dl dt {
  font-weight: 600;
  font-size: 0.86rem;
  color: var(--color-text-light);
  margin-top: 14px;
  letter-spacing: 0.03em;
}

.access-info dl dd {
  margin-left: 0;
  font-size: 0.95rem;
  color: var(--color-text);
}

.map-container {
  border-radius: var(--radius-md);
  overflow: hidden;
  box-shadow: 0 2px 8px var(--color-shadow);
}

.map-container iframe {
  width: 100%;
  height: 420px;
  border: none;
}

.map-placeholder {
  width: 100%;
  height: 420px;
  background: linear-gradient(135deg, #d8e8f0 0%, var(--color-accent-light) 100%);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  color: var(--color-text-light);
  font-size: 0.9rem;
  letter-spacing: 0.05em;
  gap: 8px;
}

/* ============================================================
   CONTACT PAGE
   ============================================================ */
.contact-info {
  background-color: var(--color-white);
  border-radius: var(--radius-md);
  padding: 36px;
  box-shadow: 0 2px 8px var(--color-shadow);
}

.contact-info h3 {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--color-primary);
  margin-bottom: 22px;
  padding-bottom: 12px;
  border-bottom: 2px solid var(--color-accent-light);
}

.contact-info address {
  font-style: normal;
  font-size: 0.93rem;
  line-height: 2.1;
  color: var(--color-text);
}


/* ============================================================
   FOOTER
   ============================================================ */
.site-footer {
  background: linear-gradient(90deg, var(--color-footer-bg) 0%, #223040 100%);
  color: #8fa8b5;
  padding: 32px 28px;
  font-size: 0.82rem;
  margin-top: auto;
}

.footer-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 16px;
  flex-wrap: wrap;
}

.footer-brand {
  font-size: 0.95rem;
  font-weight: 700;
  color: rgba(255, 255, 255, 0.75);
  letter-spacing: 0.04em;
}

.site-footer a {
  color: #8fa8b5;
  transition: color var(--transition);
}

.site-footer a:hover {
  color: var(--color-white);
}

/* ============================================================
   UTILITIES
   ============================================================ */
.card {
  background-color: var(--color-white);
  border-radius: var(--radius-md);
  padding: 36px;
  box-shadow: 0 2px 8px var(--color-shadow);
  margin-bottom: 28px;
}

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

.mt-8 {
  margin-top: 8px;
}

.mt-16 {
  margin-top: 16px;
}

.mt-24 {
  margin-top: 24px;
}

.mt-32 {
  margin-top: 32px;
}

.mb-8 {
  margin-bottom: 8px;
}

.mb-16 {
  margin-bottom: 16px;
}

.mb-24 {
  margin-bottom: 24px;
}

/* ============================================================
   SCROLL REVEAL ANIMATION
   ============================================================ */
.reveal {
  opacity: 0;
  transform: translateY(22px);
  transition: opacity var(--transition-slow), transform var(--transition-slow);
}

.reveal.is-visible {
  opacity: 1;
  transform: translateY(0);
}

/* ============================================================
   RESPONSIVE — TABLET (≤ 960px)
   ============================================================ */
@media (max-width: 960px) {
  .access-grid {
    grid-template-columns: 1fr;
  }

  /* study-card: figure を下に回す */
  .study-card {
    grid-template-columns: 1fr;
    grid-template-rows: auto auto auto;
  }

  .study-card-figure {
    border-left: none;
    border-top: 1px solid var(--color-border);
    width: 100%;
    min-height: 120px;
  }

  .footer-inner {
    flex-direction: column;
    text-align: center;
  }
}

/* ============================================================
   RESPONSIVE — MOBILE (≤ 640px)
   ============================================================ */
@media (max-width: 640px) {
  html {
    font-size: 15px;
  }

  .container {
    padding: 0 18px;
  }

  .site-title {
    font-size: 1.15rem;
    padding-right: 150px;
    /* clear lang-switch + nav-toggle */
    line-height: 1.35;
  }

  .header-inner {
    position: relative;
    padding: 14px 16px 0;
  }

  /* lang-switch の位置調整（nav-toggle の左に配置） */
  .lang-switch {
    top: 14px;
    right: 64px;
    font-size: 0.7rem;
    gap: 3px;
  }

  /* Lang buttons in header are compact – override the 44px tap target rule */
  .lang-switch .lang-btn {
    min-height: 0 !important;
    padding: 5px 9px;
    font-size: 0.7rem;
    line-height: 1;
  }

  .nav-toggle {
    display: block;
    top: 12px;
    right: 14px;
  }

  .site-nav ul {
    flex-direction: column;
    border-top: none;
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.38s ease;
  }

  .site-nav.is-open ul {
    max-height: 520px;
  }

  .site-nav li a {
    padding: 13px 18px;
    border-top: 1px solid var(--color-border);
  }

  .site-nav li a::after {
    display: none;
  }

  .keyvisual img {
    height: 230px;
  }

  .keyvisual-placeholder {
    height: 200px;
  }

  .welcome-section {
    padding: 26px 22px;
  }

  .welcome-figure img {
    max-width: 100%;
  }

  .cta-box {
    padding: 24px 20px;
  }

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

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

  .news-item:not(details),
  .news-summary {
    flex-direction: column;
    gap: 8px;
    padding: 18px 20px;
  }

  .news-content {
    padding: 0 20px 18px;
  }

  .filter-bar {
    padding: 14px 18px;
  }

  .page-header {
    padding: 20px 22px;
    margin-bottom: 32px;
  }

  .page-header h1 {
    font-size: 1.3rem;
  }

  .site-main {
    padding: 36px 0 52px;
  }

  /* ===== Study cards — mobile tuning ===== */
  .study-grid {
    gap: 22px;
  }

  .study-card-header {
    padding: 14px 18px;
  }

  .study-card-number {
    font-size: 0.85rem;
    margin-bottom: 3px;
  }

  .study-card-title {
    font-size: 1.15rem;
    line-height: 1.45;
  }

  /* Inline-styled spans inside .study-card-title need !important to override */
  .study-card-title span {
    font-size: 0.95rem !important;
    display: inline-block;
    margin-top: 4px;
  }

  .study-card-body {
    padding: 18px 20px;
    font-size: 1rem;
    line-height: 1.8;
  }

  .study-card-figure {
    padding: 10px;
    min-height: auto;
  }

  .study-card-figure img {
    width: 100%;
    max-width: 100%;
    height: auto;
  }
}

@media (max-width: 400px) {
  .member-grid {
    grid-template-columns: 1fr;
  }

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

  .study-card-title {
    font-size: 1.05rem;
  }

  .study-card-title span {
    font-size: 0.88rem !important;
  }

  .study-card-body {
    padding: 16px 18px;
    font-size: 0.95rem;
  }
}

/* ============================================================
   RESPONSIVE — GLOBAL MOBILE POLISH (≤ 640px)
   Touch targets, member/faculty cards, image safety, overflow.
   ============================================================ */
@media (max-width: 640px) {

  /* Prevent any horizontal scroll on phones */
  html,
  body {
    overflow-x: hidden;
  }

  /* Global image safety net — no image overflows its container */
  img {
    max-width: 100%;
    height: auto;
  }

  /* Touch-friendly tap targets — but NOT .nav-toggle (its 3 spans need to stack)
     and NOT .lang-btn (already sized appropriately in header) */
  .cta-btn,
  .site-nav li a {
    min-height: 44px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
  }

  /* Hamburger menu: keep 3 spans stacked vertically (≡), enlarge for touch */
  .nav-toggle {
    padding: 4px 6px;
    /* ← ボタンの枠（余白）を小さくしました */
  }

  .nav-toggle span {
    width: 18px;
    /* ← 線の横幅を短くしました */
    height: 2px;
    /* ← 線の太さを少し細くしました */
    margin: 4px 0;
    /* ← 線と線の隙間を狭くしました */
  }

  .cta-btn {
    padding: 12px 28px;
    font-size: 1rem;
  }

  /* Member / faculty cards become more compact, drop square aspect ratio */
  .faculty-card,
  .member-card {
    aspect-ratio: auto;
    padding: 22px 18px;
  }

  .faculty-card .member-avatar {
    width: 84px;
    height: 84px;
    font-size: 1.7rem;
    margin-bottom: 12px;
  }

  .member-avatar {
    width: 68px;
    height: 68px;
    font-size: 1.4rem;
    margin-bottom: 10px;
  }

  /* Map / access page */
  .access-info {
    padding: 18px 20px;
  }

  .map-container iframe,
  .map-section iframe {
    width: 100%;
    height: 280px;
  }

  /* Generic card padding */
  .card {
    padding: 20px;
  }

  /* Long tables / preformatted text — allow horizontal scroll inside */
  table,
  pre {
    display: block;
    max-width: 100%;
    overflow-x: auto;
  }

  /* Headings tighten up */
  h1 {
    font-size: 1.6rem;
    line-height: 1.3;
  }

  h2 {
    font-size: 1.3rem;
    line-height: 1.35;
  }
}

/* ============================================================
   RESPONSIVE — SMALL PHONES (≤ 400px) extras
   ============================================================ */
@media (max-width: 400px) {
  .container {
    padding: 0 14px;
  }

  .site-title {
    font-size: 1rem;
    padding-right: 130px;
    line-height: 1.3;
  }

  .lang-switch {
    right: 56px;
    top: 13px;
  }

  .lang-switch .lang-btn {
    padding: 4px 7px !important;
    font-size: 0.65rem !important;
  }

  .nav-toggle {
    top: 10px;
    right: 12px;
    padding: 6px 8px;
  }

  .nav-toggle span {
    width: 18px;
  }

  .cta-btn {
    width: 100%;
    padding: 14px 20px;
  }
}

/* ============================================================
   RESPONSIVE — INLINE-STYLE OVERRIDES FOR MOBILE
   Many pages have inline style="..." attributes that beat
   normal class selectors. These !important rules ensure mobile
   sizing wins on small screens for every HTML page.
   ============================================================ */
@media (max-width: 640px) {

  /* ----- Home page key visual (index.html, en/index.html) ----- */
  .keyvisual img[style] {
    height: 240px !important;
  }

  .keyvisual h2[style] {
    font-size: 1.6rem !important;
    margin-bottom: 10px !important;
    letter-spacing: 0.03em !important;
  }

  .keyvisual p[style] {
    font-size: 0.95rem !important;
    line-height: 1.7 !important;
  }

  .keyvisual div[style*="translate(-50%"] {
    padding: 0 16px !important;
  }

  /* ----- Welcome section (index.html, en/index.html) ----- */
  .welcome-section h2[style] {
    font-size: 1.25rem !important;
    margin-bottom: 16px !important;
    line-height: 1.4 !important;
    word-break: keep-all;
    overflow-wrap: break-word;
  }

  .welcome-section p[style] {
    font-size: 1rem !important;
    line-height: 1.8 !important;
    margin-bottom: 18px !important;
  }

  .welcome-section a[style] {
    font-size: 1.05rem !important;
    margin-top: 10px !important;
    margin-bottom: 24px !important;
    display: inline-block !important;
  }

  /* ----- Placeholder pages: news/presentation/blog "工事中" ----- */
  .site-main .container[style*="150px"] {
    padding: 70px 20px !important;
  }

  .site-main .container[style*="150px"] h2 {
    font-size: 1.4rem !important;
    margin-bottom: 14px !important;
  }

  /* ----- Study card titles with inline font-size (JP study.html) ----- */
  .study-card-title[style] {
    font-size: 1.15rem !important;
    line-height: 1.45 !important;
  }

  /* ----- Access page Google Maps iframe ----- */
  iframe[height="450"] {
    height: 280px !important;
  }

  /* ----- Map section iframes (home page map) ----- */
  .map-section iframe[style] {
    width: 100% !important;
  }
}

@media (max-width: 400px) {

  /* Even smaller phones */
  .keyvisual img[style] {
    height: 200px !important;
  }

  .keyvisual h2[style] {
    font-size: 1.35rem !important;
  }

  .keyvisual p[style] {
    font-size: 0.88rem !important;
  }

  .welcome-section h2[style] {
    font-size: 1.1rem !important;
    line-height: 1.4 !important;
    margin-bottom: 12px !important;
  }

  .welcome-section p[style] {
    font-size: 0.95rem !important;
  }

  .welcome-section a[style] {
    font-size: 1rem !important;
  }

  .site-main .container[style*="150px"] {
    padding: 56px 16px !important;
  }

  .site-main .container[style*="150px"] h2 {
    font-size: 1.25rem !important;
  }

  .study-card-title[style] {
    font-size: 1.05rem !important;
  }

  iframe[height="450"] {
    height: 240px !important;
  }
}

/* ============================================================
   SCREENSHOT-LIKE ARCHIVE LAYOUT (For Publication / News)
   ============================================================ */
.archive-container {
  max-width: var(--max-width);
  margin: 0 auto;
}

.archive-group {
  margin-bottom: 50px;
}

.archive-year-header {
  border-top: 3px solid #1a2e3a; /* Thick top border */
  padding-top: 15px;
  margin-bottom: 15px;
}

.archive-year-title {
  font-size: 1.5rem;
  font-weight: 700;
  color: #0c7f8a; /* Teal color matching the user's screenshot */
  text-decoration: none;
  display: inline-block;
  font-family: var(--font-main);
  letter-spacing: 0.03em;
  transition: color var(--transition);
}

.archive-year-title:hover {
  color: var(--color-primary-mid);
}

.archive-list {
  display: flex;
  flex-direction: column;
}

.archive-item {
  padding: 18px 8px;
  border-bottom: 1px dotted #c4d5de; /* Dotted separating line */
  font-size: 1rem;
  color: var(--color-text);
  line-height: 1.85;
  transition: background-color var(--transition), padding-left var(--transition);
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.archive-item:hover {
  background-color: rgba(143, 168, 181, 0.05);
  padding-left: 12px;
}

.archive-item-meta {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
}

.archive-item-date {
  font-size: 0.85rem;
  color: var(--color-text-light);
  font-weight: 500;
}

.archive-item-tag {
  display: inline-block;
  font-size: 0.70rem;
  padding: 2px 10px;
  border-radius: 20px;
  font-weight: 700;
  white-space: nowrap;
}

.archive-item-tag.tag-conference {
  background-color: #d4edda;
  color: #155724;
}

.archive-item-tag.tag-journal {
  background-color: #d8eef4;
  color: #0c5460;
}

.archive-item-tag.tag-invited {
  background-color: #ffe5d0;
  color: #7b3e00;
}

.archive-item-content {
  font-size: 1rem;
  color: var(--color-text);
}

/* Custom interactive search/filter bar for Publication Page */
.archive-filter-section {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 20px;
  margin-bottom: 40px;
  background-color: var(--color-white);
  padding: 20px 28px;
  border-radius: var(--radius-md);
  box-shadow: 0 2px 8px var(--color-shadow);
  flex-wrap: wrap;
}

.archive-filter-group {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
}

.archive-filter-label {
  font-weight: 700;
  font-size: 0.9rem;
  color: var(--color-text-mid);
}

.archive-filter-btn {
  background-color: var(--color-surface-alt);
  border: 1px solid var(--color-border);
  color: var(--color-text-mid);
  padding: 6px 16px;
  border-radius: 20px;
  font-size: 0.82rem;
  font-weight: 600;
  cursor: pointer;
  transition: all var(--transition);
}

.archive-filter-btn:hover {
  background-color: var(--color-accent-light);
  color: var(--color-primary);
}

.archive-filter-btn.active {
  background-color: var(--color-primary);
  border-color: var(--color-primary);
  color: var(--color-white);
  box-shadow: 0 2px 6px rgba(30, 77, 107, 0.2);
}

.archive-search-input {
  padding: 8px 16px;
  border: 1px solid var(--color-border);
  border-radius: 20px;
  font-size: 0.88rem;
  color: var(--color-text);
  outline: none;
  min-width: 260px;
  font-family: var(--font-main);
  transition: border-color var(--transition), box-shadow var(--transition);
}

.archive-search-input:focus {
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(30, 77, 107, 0.15);
}

/* Mobile responsive fixes for archive lists */
@media (max-width: 640px) {
  .archive-filter-section {
    padding: 16px;
    flex-direction: column;
    align-items: stretch;
  }
  .archive-search-input {
    min-width: 100%;
  }
  .archive-year-title {
    font-size: 1.3rem;
  }
  .archive-item {
    padding: 14px 4px;
    font-size: 0.95rem;
  }
}

/* Collapsible styles for presentation archive-item */
details.archive-item {
  display: block; /* Override default .archive-item flex layout */
  cursor: pointer;
  outline: none;
}

details.archive-item summary {
  display: flex;
  flex-direction: column;
  gap: 6px;
  list-style: none; /* Hide default arrow */
  outline: none;
  position: relative;
  padding-right: 36px;
}

details.archive-item summary::-webkit-details-marker {
  display: none; /* Hide default arrow in Safari */
}

details.archive-item summary::marker {
  display: none; /* Hide default arrow in Firefox */
}

/* Custom expand/collapse indicator */
details.archive-item summary::after {
  content: "+";
  position: absolute;
  right: 8px;
  top: 50%;
  transform: translateY(-50%);
  font-size: 1.4rem;
  font-weight: 500;
  color: var(--color-text-light);
  transition: transform var(--transition);
}

details.archive-item[open] summary::after {
  content: "−";
}

.archive-item-details {
  padding: 16px 8px 8px;
  border-top: 1px dashed var(--color-border);
  margin-top: 12px;
  cursor: default;
}

.archive-details-table {
  width: 100%;
  border-collapse: collapse;
  margin: 0;
  font-size: 0.92rem;
}

.archive-details-table th,
.archive-details-table td {
  padding: 10px 12px;
  text-align: left;
  border-bottom: 1px solid var(--color-border);
}

.archive-details-table th {
  font-weight: 700;
  color: var(--color-text-mid);
  width: 160px;
  background-color: var(--color-surface-alt);
}

.archive-details-table td {
  color: var(--color-text);
}

@media (max-width: 640px) {
  details.archive-item summary {
    padding-right: 28px;
  }
  .archive-details-table th,
  .archive-details-table td {
    display: block;
    width: 100%;
    box-sizing: border-box;
  }
  .archive-details-table th {
    background-color: transparent;
    padding-bottom: 2px;
    padding-top: 8px;
    border-bottom: none;
  }
  .archive-details-table td {
    padding-top: 2px;
    padding-bottom: 8px;
  }
}