:root {
  --green-900: #1b4332;
  --green-700: #2d6a4f;
  --green-500: #52b788;
  --green-300: #95d5b2;
  --green-100: #d8f3dc;
  --bg: #f7faf6;
  --card: #ffffff;
  --text: #22302a;
  --text-muted: #5c6b63;
  --border: #e3ebe4;
  --shadow: 0 6px 18px rgba(27, 67, 50, 0.08);
  --radius: 14px;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Hiragino Sans", "Noto Sans JP",
               "Yu Gothic UI", "Meiryo", sans-serif;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--green-700); text-decoration: none; }
a:hover { color: var(--green-500); }

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

.container {
  max-width: 1080px;
  margin: 0 auto;
  padding: 0 20px;
}

/* ---------- Header / Nav ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(247, 250, 246, 0.92);
  backdrop-filter: saturate(1.4) blur(8px);
  border-bottom: 1px solid var(--border);
}
.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 20px;
  max-width: 1080px;
  margin: 0 auto;
}
.brand {
  font-weight: 700;
  font-size: 1.1rem;
  color: var(--green-900);
  display: flex;
  align-items: center;
  gap: 8px;
}
.brand-mark { font-size: 1.3rem; }
.nav-links { display: flex; gap: 22px; }
.nav-links a {
  color: var(--text);
  font-weight: 500;
  font-size: 0.95rem;
}
.nav-links a.active { color: var(--green-700); }

/* ---------- Hero ---------- */
.hero {
  background:
    radial-gradient(circle at 20% 20%, var(--green-300) 0%, transparent 55%),
    radial-gradient(circle at 85% 10%, var(--green-100) 0%, transparent 50%),
    linear-gradient(180deg, #eaf6ee 0%, var(--bg) 100%);
  padding: 72px 20px 56px;
  text-align: center;
}
.hero h1 {
  margin: 0 0 14px;
  font-size: clamp(1.8rem, 4vw, 2.6rem);
  color: var(--green-900);
  letter-spacing: 0.02em;
}
.hero p {
  margin: 0 auto;
  max-width: 560px;
  color: var(--text-muted);
  font-size: 1.02rem;
}

/* ---------- Section ---------- */
.section {
  padding: 56px 0;
}
.section-title {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  margin: 0 0 24px;
}
.section-title h2 {
  margin: 0;
  font-size: 1.4rem;
  color: var(--green-900);
}
.section-title a {
  font-size: 0.92rem;
}

/* ---------- Card grid ---------- */
.grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 22px;
}
.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: var(--shadow);
  transition: transform 0.18s ease, box-shadow 0.18s ease;
  display: flex;
  flex-direction: column;
}
.card:hover {
  transform: translateY(-3px);
  box-shadow: 0 10px 24px rgba(27, 67, 50, 0.14);
}
.card-img {
  width: 100%;
  aspect-ratio: 16 / 10;
  object-fit: cover;
  background: var(--green-100);
}
.card-body {
  padding: 16px 18px 18px;
  display: flex;
  flex-direction: column;
  gap: 10px;
  flex: 1;
}
.card-date {
  font-size: 0.82rem;
  color: var(--green-700);
  letter-spacing: 0.04em;
}
.card-title {
  margin: 0;
  font-size: 1.05rem;
  line-height: 1.5;
  color: var(--green-900);
}
.card-meta {
  margin-top: auto;
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  font-size: 0.82rem;
  color: var(--text-muted);
}
.card-meta span { display: inline-flex; align-items: center; gap: 4px; }
.card-actions {
  display: flex;
  gap: 10px;
  margin-top: 4px;
}
.btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 8px 14px;
  border-radius: 999px;
  font-size: 0.88rem;
  font-weight: 600;
  transition: background 0.15s ease;
}
.btn-primary {
  background: var(--green-700);
  color: #fff;
}
.btn-primary:hover { background: var(--green-500); color: #fff; }
.btn-ghost {
  background: var(--green-100);
  color: var(--green-900);
}
.btn-ghost:hover { background: var(--green-300); color: var(--green-900); }

/* ---------- Activity detail page ---------- */
.detail-hero {
  position: relative;
  width: 100%;
  aspect-ratio: 16 / 9;
  overflow: hidden;
  background: var(--green-100);
}
.detail-hero img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}
.detail {
  max-width: 820px;
  margin: -60px auto 0;
  padding: 0 20px;
  position: relative;
  z-index: 2;
}
.detail-card {
  background: var(--card);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 28px 28px 32px;
  border: 1px solid var(--border);
}
.detail-date {
  color: var(--green-700);
  font-size: 0.9rem;
  letter-spacing: 0.04em;
  margin-bottom: 6px;
}
.detail-title {
  margin: 0 0 18px;
  font-size: clamp(1.3rem, 2.6vw, 1.8rem);
  color: var(--green-900);
  line-height: 1.45;
}
.stats {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(110px, 1fr));
  gap: 12px;
  background: var(--green-100);
  border-radius: 10px;
  padding: 16px;
  margin: 18px 0 22px;
}
.stat-label {
  display: block;
  font-size: 0.76rem;
  color: var(--green-700);
  margin-bottom: 2px;
}
.stat-value {
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--green-900);
}
.detail-body p {
  margin: 0 0 14px;
  color: var(--text);
}
.detail-footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-top: 22px;
  padding-top: 18px;
  border-top: 1px solid var(--border);
  font-size: 0.9rem;
}

/* ---------- Profile / About ---------- */
.profile {
  max-width: 720px;
  margin: 0 auto;
}
.profile-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 32px 28px;
  box-shadow: var(--shadow);
  text-align: center;
}
.avatar {
  width: 96px;
  height: 96px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--green-300), var(--green-700));
  margin: 0 auto 16px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 2.4rem;
  color: #fff;
}
.profile h2 { margin: 0 0 8px; color: var(--green-900); }
.profile .bio { color: var(--text-muted); }

/* ---------- Footer ---------- */
.site-footer {
  margin-top: 60px;
  padding: 28px 20px;
  text-align: center;
  color: var(--text-muted);
  font-size: 0.85rem;
  border-top: 1px solid var(--border);
}

/* ---------- Responsive ---------- */
@media (max-width: 640px) {
  .nav-links { gap: 14px; }
  .hero { padding: 56px 18px 44px; }
  .section { padding: 40px 0; }
  .detail { margin-top: -40px; }
  .detail-card { padding: 22px 18px 24px; }
}