:root {
  --bg: #f7f7f9;
  --panel: #ffffff;
  --text: #1f2328;
  --muted: #6b7280;
  --accent: #d9534f;
  --accent-bg: #fdecec;
  --border: #e5e7eb;
  --code-bg: #0f172a;
  --code-text: #e2e8f0;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: -apple-system, "Segoe UI", "Hiragino Kaku Gothic ProN",
               "Yu Gothic UI", Meiryo, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.75;
}

.site-header {
  background: var(--panel);
  border-bottom: 1px solid var(--border);
  padding: 12px 28px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 12px;
}
.header-main {
  display: flex;
  align-items: baseline;
  gap: 14px;
  flex-wrap: wrap;
}
.brand {
  font-weight: 700;
  font-size: 1.15rem;
  color: var(--accent);
  text-decoration: none;
}
.tagline { color: var(--muted); font-size: 0.9rem; }
.sister-nav {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
}
.sister-nav a {
  font-size: 0.85rem;
  color: var(--text);
  text-decoration: none;
  padding: 4px 10px;
  border: 1px solid var(--border);
  border-radius: 999px;
  background: #fff;
  white-space: nowrap;
}
.sister-nav a:hover {
  border-color: var(--accent);
  color: var(--accent);
}

.positioning {
  background: #fff7ed;
  border-left: 4px solid #fb923c;
  padding: 12px 16px;
  border-radius: 4px;
  margin: 18px 0 24px;
  font-size: 0.95rem;
}
.positioning a { color: var(--accent); }

.sister-card .num { font-size: 1.5rem; }
.footer-sister { margin-bottom: 6px; font-size: 0.9rem; }
.footer-sister a { color: var(--accent); text-decoration: none; }
.footer-sister a:hover { text-decoration: underline; }

.layout {
  display: grid;
  grid-template-columns: 240px 1fr;
  gap: 28px;
  max-width: 1100px;
  margin: 28px auto;
  padding: 0 24px;
}

.sidebar {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 18px 16px;
  height: fit-content;
  position: sticky;
  top: 16px;
}
.sidebar-title {
  margin: 0 0 8px;
  font-size: 0.8rem;
  color: var(--muted);
  letter-spacing: 0.05em;
}
.sidebar ol { padding-left: 20px; margin: 0; }
.sidebar li { margin: 6px 0; }
.sidebar a {
  color: var(--text);
  text-decoration: none;
  font-size: 0.95rem;
}
.sidebar a:hover { color: var(--accent); }
.sidebar a.active {
  color: var(--accent);
  font-weight: 600;
}

.content {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 32px 36px;
  min-height: 60vh;
}

h1 {
  margin-top: 0;
  font-size: 1.8rem;
  border-bottom: 2px solid var(--accent);
  padding-bottom: 8px;
  display: inline-block;
}
h2 {
  margin-top: 2em;
  font-size: 1.25rem;
  border-left: 4px solid var(--accent);
  padding-left: 10px;
}

.lead {
  color: var(--muted);
  font-size: 1.02rem;
  margin: 8px 0 24px;
}

kbd {
  display: inline-block;
  padding: 2px 8px;
  font-family: ui-monospace, "Consolas", monospace;
  font-size: 0.85rem;
  background: #fff;
  border: 1px solid #cbd5e1;
  border-bottom-width: 2px;
  border-radius: 4px;
  color: #334155;
}

pre {
  background: var(--code-bg);
  color: var(--code-text);
  padding: 14px 18px;
  border-radius: 8px;
  overflow-x: auto;
  font-size: 0.9rem;
}
code { font-family: ui-monospace, "Consolas", monospace; }
p > code, li > code {
  background: #eef2f7;
  color: #b91c1c;
  padding: 1px 6px;
  border-radius: 4px;
  font-size: 0.88em;
}

.note {
  background: var(--accent-bg);
  border-left: 4px solid var(--accent);
  padding: 10px 14px;
  border-radius: 4px;
  margin: 16px 0;
  font-size: 0.95rem;
}

.screenshot {
  margin: 18px 0;
  border: 1px dashed #cbd5e1;
  border-radius: 8px;
  padding: 14px;
  background: #fafbfc;
  text-align: center;
  color: var(--muted);
  font-size: 0.9rem;
}
.screenshot img {
  max-width: 100%;
  border-radius: 6px;
  display: block;
  margin: 0 auto 8px;
  border: 1px solid var(--border);
}

table.shortcuts {
  width: 100%;
  border-collapse: collapse;
  margin: 12px 0;
}
table.shortcuts th, table.shortcuts td {
  text-align: left;
  border-bottom: 1px solid var(--border);
  padding: 8px 10px;
  font-size: 0.95rem;
}
table.shortcuts th {
  background: #f1f5f9;
  font-weight: 600;
}

.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 14px;
  margin-top: 20px;
}
.card {
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 16px;
  text-decoration: none;
  color: var(--text);
  background: #fff;
  transition: transform 0.1s, border-color 0.1s;
}
.card:hover {
  border-color: var(--accent);
  transform: translateY(-2px);
}
.card .num {
  color: var(--accent);
  font-weight: 700;
  font-size: 0.85rem;
}
.card h3 { margin: 4px 0 6px; font-size: 1.05rem; }
.card p { margin: 0; color: var(--muted); font-size: 0.9rem; }

.pager {
  display: flex;
  justify-content: space-between;
  margin-top: 36px;
  padding-top: 16px;
  border-top: 1px solid var(--border);
}
.pager a {
  color: var(--accent);
  text-decoration: none;
  font-size: 0.95rem;
}
.pager a:hover { text-decoration: underline; }

.site-footer {
  text-align: center;
  padding: 20px;
  color: var(--muted);
}

@media (max-width: 720px) {
  .layout { grid-template-columns: 1fr; }
  .sidebar { position: static; }
}