/* Earth Science Week Japan — site shell */
*, *::before, *::after { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: "Helvetica", "ヒラギノ丸ゴ Pro W4", "メイリオ", "Avenir Next", sans-serif;
  font-size: 16px;
  line-height: 1.6;
  color: #222;
  background: #fff;
}

a { color: #003259; }
a:hover { color: #62c0eb; }

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

.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  background: #003259;
  border-bottom: 5px solid #78cda6;
}

.site-header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  max-width: 1200px;
  margin: 0 auto;
  padding: 8px 16px;
}

.site-logo img { width: 120px; padding: 6px 0; }

.site-nav__list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  margin: 0;
  padding: 0;
  list-style: none;
}

.site-nav__list > li { border-left: 2px solid #62c0eb; }
.site-nav__list > li:last-child { border-right: 2px solid #62c0eb; }

.site-nav__list a,
.site-nav__label {
  display: block;
  padding: 18px 24px;
  color: #f0f8ff;
  text-decoration: none;
  font-size: 15px;
  white-space: nowrap;
}

.site-nav__label { cursor: default; }
.site-nav__list a:hover { color: #62c0eb; }

.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 36px;
  height: 32px;
  padding: 4px;
  border: 1px solid #c0c0c0;
  border-radius: 3px;
  background: #fff;
  cursor: pointer;
}

.nav-toggle span { display: block; height: 2px; background: #c0c0c0; }
.nav-overlay { display: none; }

.page-main { padding-top: 90px; min-height: 60vh; }
.page-main--home { padding-top: 80px; }

.page-header {
  max-width: 1100px;
  margin: 0 auto;
  padding: 24px 20px 0;
}

.page-header h1 {
  margin: 0;
  color: #00008b;
  font-size: 1.75rem;
}

.page-content {
  max-width: 1100px;
  margin: 0 auto;
  padding: 20px;
}

.hero-slider {
  background: #003259;
  padding: 30px 0 20px;
}

.hero-slider__track {
  display: flex;
  flex-wrap: nowrap;
  gap: 24px;
  overflow-x: auto;
  scroll-snap-type: x mandatory;
  padding: 0 20px 16px;
}

.hero-card {
  flex: 0 0 min(700px, 85vw);
  scroll-snap-align: center;
  background: #fff;
}

.hero-card__image img { width: 100%; display: block; }
.hero-card__body { padding: 16px 20px 20px; }
.hero-card__title { font-weight: bold; margin: 0 0 8px; color: #00008b; }
.hero-card__desc { margin: 0 0 12px; font-size: 0.95rem; }

.hero-card__link a {
  display: inline-block;
  padding: 8px 16px;
  background: #003259;
  color: #fff;
  text-decoration: none;
  border-radius: 3px;
}

.hero-card__link a:hover { background: #62c0eb; color: #003259; }

.home-video { display: flex; justify-content: center; padding: 30px 20px; }
.home-video iframe { max-width: 100%; border: 0; }

.home-columns {
  display: flex;
  flex-wrap: wrap;
  gap: 24px;
  max-width: 1100px;
  margin: 0 auto;
  padding: 20px;
}

.home-columns__main { flex: 1 1 320px; }
.home-columns__aside { flex: 0 1 280px; }

.section-block h1, .section-block h2 {
  text-align: center;
  color: #00008b;
  margin: 0 0 16px;
}

.topic-list, .abst-list { list-style: none; margin: 0; padding: 0; }
.topic-list li {
  margin: 10px 0;
  padding: 12px;
  border: 1px solid #ccc;
  border-radius: 3px;
  box-shadow: 2px 2px 4px rgba(0,0,0,0.15);
}

.abst-list li { margin: 8px 0; }

.twitter-placeholder {
  padding: 16px;
  background: #f5f8fa;
  border-radius: 8px;
  text-align: center;
  color: #1DA1F2;
}

.plan-grid {
  display: flex;
  flex-wrap: wrap;
  gap: 24px;
  justify-content: center;
  padding: 20px;
}

.plan-grid .hero-card { flex: 0 1 340px; }

.content-section { max-width: 1100px; margin: 0 auto; padding: 20px; }
.content-section h1, .content-section h2, .content-section h3 { color: #00008b; }

.blog-page-title { text-align: center; color: #00008b; margin: 0 0 24px; }
.blog-container { max-width: 1100px; margin: 0 auto; }
.blog-grid { display: flex; flex-wrap: wrap; gap: 20px; }

.blog-card {
  flex: 1 1 280px;
  border: 1px solid #ddd;
  border-radius: 4px;
  padding: 16px;
  background: #fafafa;
}

.blog-title { margin: 0 0 8px; font-size: 1.1rem; }
.blog-title a { text-decoration: none; }
.blog-preview p { margin: 0; font-size: 0.9rem; color: #555; }

.site-footer {
  margin-top: 40px;
  background: #9fc1dc;
  padding: 20px 16px;
}

.site-footer__inner { max-width: 1100px; margin: 0 auto; text-align: center; }
.site-footer__copy { margin: 12px 0 0; font-size: 10px; }

@media (max-width: 900px) {
  .nav-toggle { display: flex; }
  .site-nav {
    position: fixed;
    top: 0;
    right: 0;
    width: min(100%, 320px);
    height: 100vh;
    background: #fff;
    transform: translateX(100%);
    transition: transform 0.3s ease;
    z-index: 101;
    overflow-y: auto;
  }
  .site-nav.is-open { transform: translateX(0); }
  .site-nav__list { flex-direction: column; padding-top: 60px; }
  .site-nav__list > li { width: 100%; border-left: none; border-bottom: 1px solid #c0c0c0; }
  .site-nav__list > li:last-child { border-right: none; }
  .site-nav__list a, .site-nav__label { color: #222; text-align: center; }
  .nav-overlay {
    display: block;
    position: fixed;
    inset: 0;
    background: rgba(0,0,0,0.5);
    z-index: 100;
  }
  body.nav-open { overflow: hidden; }
}

@media (max-width: 600px) {
  .page-main { padding-top: 76px; }
  .hero-card { flex: 0 0 92vw; }
}