:root {
  --bg: #f7f4ee;
  --ink: #0f172a;
  --muted: #475569;
  --line: rgba(15, 23, 42, 0.14);
  --panel: #fffaf0;
  --accent: #ed6651;
  --accent-soft: #efe0b7;
  --max-width: 1000px;
}

* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  padding: 0;
}

body {
  min-height: 100vh;
  color: var(--ink);
  background:
    linear-gradient(180deg, rgba(15, 23, 42, 0.04) 2.08%, rgba(15, 23, 42, 0) 2.08%),
    linear-gradient(90deg, rgba(15, 23, 42, 0.04) 2.08%, rgba(15, 23, 42, 0) 2.08%),
    var(--bg);
  background-size: 48px 48px, 48px 48px, auto;
  font-family: "IBM Plex Sans JP", "Hiragino Kaku Gothic ProN", "Yu Gothic", "Noto Sans JP", sans-serif;
}

a {
  color: inherit;
  text-decoration: none;
}

.container {
  width: min(100%, var(--max-width));
  margin: 0 auto;
  padding: 0 24px;
}

.site-header {
  background: rgba(247, 244, 238, 0.88);
  backdrop-filter: blur(3px);
}

.header-inner,
.footer-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
}

.header-inner {
  padding: 18px 24px;
}

.logo {
  width: 130px;
  height: auto;
  display: block;
}

.header-nav,
.footer-links {
  display: flex;
  align-items: center;
  gap: 22px;
  font-size: 14px;
  font-weight: 700;
}

.notes-hero {
  padding: 72px 0 44px;
}

.eyebrow {
  margin: 0 0 14px;
  color: var(--accent);
  font-size: 13px;
  font-weight: 800;
  letter-spacing: 0.08em;
}

h1,
h2,
h3 {
  letter-spacing: 0;
}

.notes-hero h1,
.article-hero h1 {
  margin: 0;
  max-width: 820px;
  font-size: clamp(36px, 6vw, 64px);
  line-height: 1.14;
  font-weight: 800;
}

.notes-lead,
.article-lead {
  max-width: 720px;
  margin: 22px 0 0;
  color: #1e293b;
  font-size: 18px;
  line-height: 1.85;
  font-weight: 600;
}

.note-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 18px;
  padding: 20px 0 76px;
}

.note-card {
  display: flex;
  min-height: 330px;
  flex-direction: column;
  justify-content: space-between;
  border: 2px solid var(--ink);
  border-radius: 24px;
  background: var(--panel);
  padding: 24px;
  box-shadow: 5px 5px 0 var(--ink);
}

.note-card:hover {
  transform: translate(-2px, -2px);
  box-shadow: 7px 7px 0 var(--ink);
}

.note-meta,
.article-meta {
  color: var(--muted);
  font-size: 13px;
  font-weight: 700;
}

.note-card h2 {
  margin: 18px 0 0;
  font-size: 25px;
  line-height: 1.36;
}

.note-card p {
  margin: 16px 0 0;
  color: var(--muted);
  line-height: 1.75;
  font-weight: 600;
}

.note-arrow {
  display: inline-flex;
  margin-top: 22px;
  color: var(--accent);
  font-weight: 800;
}

.article-hero {
  padding: 58px 0 34px;
}

.article-shell {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 280px;
  gap: 44px;
  align-items: start;
  padding-bottom: 84px;
}

.article-body {
  border: 2px solid var(--ink);
  border-radius: 24px;
  background: var(--panel);
  padding: clamp(24px, 5vw, 48px);
}

.article-body h2 {
  margin: 42px 0 14px;
  font-size: 29px;
  line-height: 1.35;
}

.article-body h2:first-child {
  margin-top: 0;
}

.article-body h3 {
  margin: 28px 0 10px;
  font-size: 21px;
  line-height: 1.45;
}

.article-body p,
.article-body li {
  color: #233044;
  font-size: 17px;
  line-height: 1.95;
  font-weight: 500;
}

.article-body ul,
.article-body ol {
  padding-left: 1.4em;
}

.article-body strong {
  color: var(--ink);
}

.callout {
  margin: 34px 0;
  border-left: 6px solid var(--accent);
  border-radius: 18px;
  background: var(--accent-soft);
  padding: 22px;
}

.article-cta,
.sidebar-card {
  border: 2px solid var(--ink);
  border-radius: 24px;
  background: var(--accent-soft);
  padding: 24px;
}

.article-cta h2,
.sidebar-card h2 {
  margin: 0;
  font-size: 24px;
  line-height: 1.35;
}

.article-cta p,
.sidebar-card p {
  margin: 14px 0 0;
  color: #233044;
  line-height: 1.8;
  font-weight: 600;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 48px;
  margin-top: 18px;
  border: 2px solid var(--ink);
  border-radius: 999px;
  background: var(--ink);
  color: #fff;
  padding: 0 22px;
  font-weight: 800;
}

.button.secondary {
  background: transparent;
  color: var(--ink);
}

.sidebar {
  position: sticky;
  top: 24px;
  display: grid;
  gap: 16px;
}

.sidebar-card ul {
  margin: 14px 0 0;
  padding-left: 1.1em;
}

.sidebar-card li {
  margin: 8px 0;
  color: #233044;
  line-height: 1.6;
}

.breadcrumb {
  display: flex;
  gap: 8px;
  align-items: center;
  flex-wrap: wrap;
  margin-bottom: 24px;
  color: var(--muted);
  font-size: 14px;
  font-weight: 700;
}

.site-footer {
  border-top: 1px solid var(--ink);
  padding: 42px 0 52px;
}

.footer-inner {
  flex-direction: column;
  justify-content: center;
}

.footer-logo {
  width: 138px;
}

@media (max-width: 840px) {
  .header-inner {
    align-items: flex-start;
    flex-direction: column;
  }

  .header-nav,
  .footer-links {
    flex-wrap: wrap;
    gap: 14px;
  }

  .note-grid,
  .article-shell {
    grid-template-columns: 1fr;
  }

  .note-card {
    min-height: auto;
  }

  .sidebar {
    position: static;
  }
}