/* =========================
   Base
========================= */

:root {
  --bg: #f6f8fb;
  --card: #ffffff;
  --text: #1f2937;
  --subtext: #6b7280;
  --accent: #2563eb;
  --accent-soft: #e8f0ff;
  --border: #e5e7eb;
  --radius: 12px;
  --shadow: 0 6px 18px rgba(0,0,0,0.06);
  --font: "Segoe UI", "Noto Sans JP", system-ui, sans-serif;
}


/* =========================
   Article Container
========================= */



/* =========================
   Headings
========================= */

h2 {
  font-size: 1.8rem;
  margin-bottom: 1.5rem;
  padding-bottom: .5rem;
  border-bottom: 2px solid var(--border);
}

h3 {
  font-size: 1.2rem;
  margin: 1.5rem 0 1rem;
}

/* Excel講座タイトルリンク */
h3 a {
  text-decoration: none;
  color: var(--accent);
  font-weight: 600;
  transition: .2s;
}

h3 a:hover {
  opacity: .7;
}

/* =========================
   Lists
========================= */

article ol {
  padding-left: 1.4rem;
  margin: 0;
}

li {
  margin: .35rem 0;
}

/* 第1階層 */
article >section > div >  ol > li {
  margin-top: 1rem;
  padding: 12px 16px;
  background: #fafafa;
  border-radius: 10px;
  border: 1px solid var(--border);
}

/* 第2階層 */
article ol ol,article ol ul {
  margin-top: .6rem;
  padding-left: 1.2rem;
}

/* =========================
   Links
========================= */

a {
  color: var(--text);
  text-decoration: none;
  padding: 4px 6px;
  border-radius: 6px;
  transition: all .15s ease;
}

a:hover {
  background: var(--accent-soft);
  color: var(--accent);
}

/* =========================
   Hover interaction
========================= */

li:hover {
  transform: translateX(2px);
  transition: transform .15s ease;
}

/* =========================
   Responsive
========================= */

@media (max-width: 700px) {
  article {
    margin: 16px;
    padding: 20px;
  }

  h2 {
    font-size: 1.4rem;
  }
}

/* =========================
   Dark Mode
========================= */

@media (prefers-color-scheme: dark) {

  :root {
    --bg: #0f172a;
    --card: #111827;
    --text: #e5e7eb;
    --subtext: #9ca3af;
    --border: #1f2937;
    --accent-soft: rgba(37,99,235,.2);
    --shadow: none;
  }

  article section ol > li {
    background: #0b1220;
  }
}