:root {
  --bg: #f4f6f8;
  --surface: #ffffff;
  --text: #111827;
  --muted: #4b5563;
  --accent: #00296b;
  --border: #dbe2ea;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: "Inter", system-ui, -apple-system, "Hiragino Kaku Gothic ProN", "Noto Sans JP", "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  color: var(--text);
  background: var(--bg);
  margin: 0;
  line-height: 1.75;
}

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

a:hover {
  text-decoration: underline;
}

.container {
  max-width: 1040px;
  margin: 0 auto;
  padding: 32px 24px;
}

.site-header {
  background: var(--surface);
  border-bottom: 1px solid rgba(15, 23, 42, 0.08);
  position: sticky;
  top: 0;
  z-index: 20;
  backdrop-filter: blur(10px);
}

.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

.site-title {
  font-weight: 800;
  letter-spacing: -0.04em;
  text-decoration: none;
  color: var(--text);
  font-size: 1.4rem;
}

.main-nav {
  display: flex;
  gap: 22px;
  align-items: center;
}

.main-nav a {
  color: var(--muted);
  font-weight: 600;
}

.main-nav a:hover {
  color: var(--accent);
}

.hero {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 24px;
  padding: 40px 36px;
  margin-bottom: 32px;
}

.hero h1 {
  margin: 0 0 16px;
  font-size: clamp(2.6rem, 3vw, 3.8rem);
  letter-spacing: -0.05em;
}

.hero p {
  max-width: 760px;
  color: var(--muted);
  font-size: 1.05rem;
}

.post-list {
  list-style: none;
  padding: 0;
  margin: 0;
  display: grid;
  gap: 20px;
}

.post-card {
  display: grid;
  grid-template-columns: 220px 1fr;
  gap: 22px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 18px;
  overflow: hidden;
}

.post-card-thumb {
  min-height: 160px;
  overflow: hidden;
  background: #f8fafc;
}

.post-card-thumb img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}

.post-card-body {
  padding: 22px;
}

.post-card-title {
  display: block;
  font-size: 1.18rem;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 14px;
}

.post-card-title:hover {
  color: var(--accent);
}

.post-card .summary {
  color: var(--muted);
  margin: 0;
}

@media (max-width: 760px) {
  .post-card {
    grid-template-columns: 1fr;
  }

  .post-card-thumb {
    min-height: 220px;
  }
}

.article {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 24px;
  padding: 36px;
}

.article h1 {
  margin-top: 0;
  font-size: clamp(2rem, 2.5vw, 3rem);
}

.article .meta {
  color: var(--muted);
  margin: 16px 0 32px;
}

.article .content p {
  max-width: 760px;
}

.site-footer {
  margin-top: 56px;
  padding: 30px 0 40px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 18px;
  color: var(--muted);
}

.site-footer nav {
  display: flex;
  gap: 18px;
}

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

@media (max-width: 840px) {
  .container {
    padding: 24px 18px;
  }

  .site-header .container {
    flex-direction: column;
    align-items: flex-start;
  }

  .main-nav {
    flex-wrap: wrap;
    gap: 16px;
  }
}

@media (max-width: 640px) {
  .hero {
    padding: 28px 20px;
  }

  .article {
    padding: 24px 20px;
  }
}