/* ══════════════════════════════════════════════════
   Number Sudoku — SEO Content Styles (seo.css)
   ══════════════════════════════════════════════════ */

/* ─── Breadcrumb ─── */
.ns-breadcrumb {
  background: var(--card);
  border-bottom: 1px solid var(--border);
  padding: 8px 0;
  font-size: 13px;
  color: var(--text-sec);
}
.ns-breadcrumb-inner {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 24px;
  display: flex;
  align-items: center;
  gap: 8px;
}
.ns-breadcrumb a { color: var(--primary); text-decoration: none; }
.ns-breadcrumb a:hover { text-decoration: underline; }
.ns-breadcrumb span:not(:last-child) { color: var(--text-sec); }

/* ─── Difficulty Quick-Links ─── */
.ns-diff-links {
  background: var(--card);
  border-bottom: 1px solid var(--border);
  padding: 12px 0;
}
.ns-diff-links-inner {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 24px;
  display: flex;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
}
.ns-diff-links-label {
  font-size: 13px;
  font-weight: 600;
  color: var(--text-sec);
  margin-right: 4px;
}
.ns-diff-pill {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  padding: 6px 16px;
  border-radius: 20px;
  font-size: 13px;
  font-weight: 600;
  text-decoration: none;
  border: 1.5px solid var(--border);
  color: var(--text-sec);
  background: var(--bg);
  transition: all 0.2s;
  cursor: pointer;
}
.ns-diff-pill:hover, .ns-diff-pill.active { color: var(--primary); border-color: var(--primary); background: var(--primary-light); }
.ns-diff-pill.easy.active   { color: #22a05a; border-color: #22a05a; background: #e8f8f0; }
.ns-diff-pill.hard.active   { color: #d94e2a; border-color: #d94e2a; background: #fdf0ec; }
.ns-diff-pill.expert.active { color: #7b3fe4; border-color: #7b3fe4; background: #f3eeff; }
.ns-diff-pill.daily.active  { color: #0284c7; border-color: #0284c7; background: #e0f2fe; }

/* ─── SEO Wrapper ─── */
.ns-seo-wrap {
  max-width: 100%;
}

/* ─── SEO Section Base ─── */
.ns-seo-section {
  padding: 72px 24px;
  background: var(--bg);
}
.ns-seo-section.ns-seo-alt {
  background: var(--card);
}
.ns-seo-inner {
  max-width: 1060px;
  margin: 0 auto;
}
.ns-seo-h2 {
  font-family: 'Outfit', sans-serif;
  font-size: clamp(24px, 3.5vw, 34px);
  font-weight: 800;
  color: var(--text);
  margin-bottom: 14px;
  line-height: 1.2;
}
.ns-seo-lead {
  font-size: 16px;
  color: var(--text-sec);
  line-height: 1.7;
  max-width: 760px;
  margin-bottom: 48px;
}

/* ─── How to Play Steps ─── */
.ns-steps-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 24px;
  margin-bottom: 56px;
}
.ns-step-card {
  background: var(--card);
  border: 1.5px solid var(--border);
  border-radius: 16px;
  padding: 28px 24px;
  transition: box-shadow 0.2s, transform 0.2s;
}
.ns-step-card:hover {
  box-shadow: 0 8px 32px rgba(61,90,153,0.1);
  transform: translateY(-3px);
}
.ns-step-icon {
  width: 56px;
  height: 56px;
  margin-bottom: 18px;
}
.ns-step-icon svg { width: 56px; height: 56px; }
.ns-step-card h3 {
  font-family: 'Outfit', sans-serif;
  font-size: 16px;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 10px;
}
.ns-step-card p {
  font-size: 14px;
  color: var(--text-sec);
  line-height: 1.6;
}

/* ─── 3 Golden Rules Visual ─── */
.ns-rule-visual {
  background: var(--primary-lighter);
  border-radius: 20px;
  padding: 40px 32px;
  border: 1.5px solid var(--border);
}
.ns-three-rules {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 28px;
}
.ns-rule-card {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  gap: 16px;
}
.ns-rule-card p {
  font-size: 14px;
  color: var(--text-sec);
  line-height: 1.5;
}
.ns-rule-demo {
  background: var(--card);
  border-radius: 12px;
  padding: 12px;
  border: 1.5px solid var(--border);
  display: inline-flex;
}
.ns-rd-row { display: flex; gap: 3px; }
.ns-rd-col { display: flex; flex-direction: column; gap: 3px; }
.ns-rd-box { display: grid; grid-template-columns: repeat(3,1fr); gap: 3px; }
.ns-rd-cell {
  width: 28px; height: 28px;
  display: flex; align-items: center; justify-content: center;
  font-size: 12px; font-weight: 700;
  border-radius: 5px;
  background: var(--primary-light);
  color: var(--primary);
  font-family: 'DM Sans', sans-serif;
}
.ns-rd-cell.g { background: var(--primary-lighter); color: var(--text-sec); }
.ns-rd-cell.active { background: var(--primary); color: #fff; }

/* ─── Difficulty Table ─── */
.ns-diff-table-wrap {
  overflow-x: auto;
  margin-bottom: 48px;
  border-radius: 14px;
  border: 1.5px solid var(--border);
}
.ns-diff-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 14px;
}
.ns-diff-table th {
  background: var(--primary);
  color: #fff;
  padding: 14px 18px;
  text-align: left;
  font-weight: 700;
  font-family: 'Outfit', sans-serif;
  font-size: 13px;
  letter-spacing: 0.3px;
}
.ns-diff-table th:first-child { border-radius: 12px 0 0 0; }
.ns-diff-table th:last-child  { border-radius: 0 12px 0 0; }
.ns-diff-table td {
  padding: 14px 18px;
  border-bottom: 1px solid var(--border);
  color: var(--text-sec);
  vertical-align: middle;
}
.ns-diff-table td a { color: var(--primary); text-decoration: none; font-weight: 700; }
.ns-diff-table td a:hover { text-decoration: underline; }
.ns-diff-table tbody tr:last-child td { border-bottom: none; }
.ns-diff-table tbody tr:hover { background: var(--primary-lighter); }
.easy-row td:first-child   { font-weight: 700; color: #22a05a; }
.medium-row td:first-child { font-weight: 700; color: var(--primary); }
.hard-row td:first-child   { font-weight: 700; color: #d94e2a; }
.expert-row td:first-child { font-weight: 700; color: #7b3fe4; }

/* ─── Difficulty Info Cards ─── */
.ns-diff-cards-row {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 20px;
  margin-top: 8px;
}
.ns-diff-info-card {
  border-radius: 16px;
  padding: 28px 22px;
  border: 1.5px solid var(--border);
  background: var(--bg);
  display: flex;
  flex-direction: column;
  gap: 10px;
}
.ns-seo-alt .ns-diff-info-card { background: var(--card); }
.ns-dic-emoji { font-size: 30px; }
.ns-diff-info-card h3 {
  font-family: 'Outfit', sans-serif;
  font-size: 16px;
  font-weight: 700;
  color: var(--text);
}
.ns-diff-info-card h3 a { color: inherit; text-decoration: none; }
.ns-diff-info-card p { font-size: 13px; color: var(--text-sec); line-height: 1.6; flex: 1; }
.ns-dic-btn {
  display: inline-block;
  margin-top: 6px;
  font-size: 13px;
  font-weight: 700;
  color: var(--primary);
  text-decoration: none;
  padding: 8px 16px;
  border-radius: 8px;
  background: var(--primary-light);
  transition: background 0.2s;
}
.ns-dic-btn:hover { background: var(--primary); color: #fff; }

/* ─── Tips Grid ─── */
.ns-tips-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 24px;
}
.ns-tip-card {
  background: var(--card);
  border: 1.5px solid var(--border);
  border-radius: 16px;
  padding: 28px 24px;
  position: relative;
  overflow: hidden;
}
.ns-tip-num {
  font-family: 'Outfit', sans-serif;
  font-size: 36px;
  font-weight: 800;
  color: var(--primary-light);
  line-height: 1;
  margin-bottom: 8px;
}
.ns-tip-card h3 {
  font-family: 'Outfit', sans-serif;
  font-size: 16px;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 10px;
}
.ns-tip-card p {
  font-size: 14px;
  color: var(--text-sec);
  line-height: 1.65;
}
/* Tip visuals */
.ns-tip-visual {
  margin-top: 18px;
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 8px;
}
.ns-tip-visual span {
  font-size: 12px;
  color: var(--text-sec);
  font-style: italic;
}
.ns-tv-grid {
  display: grid;
  grid-template-columns: repeat(3,1fr);
  gap: 4px;
}
.ns-tv-cell {
  width: 36px; height: 36px;
  border-radius: 7px;
  display: flex; align-items: center; justify-content: center;
  font-size: 13px; font-weight: 700;
  background: var(--primary-lighter);
  color: var(--text-sec);
  border: 1.5px solid var(--border);
}
.ns-tv-cell.x     { background: #fdf0ec; color: #d94e2a; border-color: #d94e2a; }
.ns-tv-cell.check { background: #e8f8f0; color: #22a05a; border-color: #22a05a; font-size: 16px; }
.ns-tv-note-cell {
  display: grid;
  grid-template-columns: repeat(3,1fr);
  gap: 2px;
  width: 70px; height: 70px;
  background: var(--primary-lighter);
  border: 1.5px solid var(--primary);
  border-radius: 8px;
  padding: 6px;
}
.ns-tv-note-cell span {
  font-size: 11px;
  font-weight: 700;
  color: var(--primary);
  display: flex;
  align-items: center;
  justify-content: center;
  font-style: normal;
}
.ns-tip-visual--wide { flex-direction: row; align-items: center; }
.ns-tv-naked {
  display: flex;
  align-items: center;
  gap: 10px;
}
.ns-tv-naked-cell {
  padding: 8px 14px;
  border-radius: 8px;
  font-size: 13px;
  border: 1.5px solid var(--border);
  background: var(--primary-lighter);
  color: var(--text-sec);
  white-space: nowrap;
}
.ns-tv-naked-cell strong { color: var(--primary); }
.ns-tv-naked-cell.answer {
  background: var(--primary);
  color: #fff;
  font-weight: 800;
  font-size: 18px;
  width: 44px; height: 44px;
  display: flex; align-items: center; justify-content: center;
  padding: 0;
}

/* ─── Features Grid ─── */
.ns-features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 20px;
}
.ns-feat-card {
  display: flex;
  gap: 18px;
  align-items: flex-start;
  background: var(--bg);
  border: 1.5px solid var(--border);
  border-radius: 16px;
  padding: 24px 20px;
}
.ns-seo-alt .ns-feat-card { background: var(--card); }
.ns-feat-icon { flex-shrink: 0; width: 44px; height: 44px; }
.ns-feat-icon svg { width: 44px; height: 44px; }
.ns-feat-card h3 {
  font-family: 'Outfit', sans-serif;
  font-size: 15px;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 6px;
}
.ns-feat-card p {
  font-size: 13px;
  color: var(--text-sec);
  line-height: 1.6;
}

/* ─── FAQ ─── */
.ns-faq-list {
  display: flex;
  flex-direction: column;
  gap: 0;
  border: 1.5px solid var(--border);
  border-radius: 16px;
  overflow: hidden;
}
.ns-faq-item { border-bottom: 1px solid var(--border); }
.ns-faq-item:last-child { border-bottom: none; }
.ns-faq-q {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  background: var(--card);
  border: none;
  padding: 20px 24px;
  cursor: pointer;
  text-align: left;
  font-family: 'DM Sans', sans-serif;
  font-size: 15px;
  font-weight: 600;
  color: var(--text);
  transition: background 0.15s;
}
.ns-faq-q:hover { background: var(--primary-lighter); }
.ns-faq-arrow {
  width: 20px; height: 20px;
  flex-shrink: 0;
  color: var(--text-sec);
  transition: transform 0.3s ease;
}
.ns-faq-item.open .ns-faq-arrow { transform: rotate(180deg); }
.ns-faq-item.open .ns-faq-q { background: var(--primary-lighter); color: var(--primary); }
.ns-faq-a {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.35s ease, padding 0.25s ease;
  background: var(--card);
  padding: 0 24px;
}
.ns-faq-item.open .ns-faq-a {
  max-height: 300px;
  padding: 4px 24px 20px;
}
.ns-faq-a p {
  font-size: 14px;
  color: var(--text-sec);
  line-height: 1.7;
}

/* ─── Keyboard Shortcuts ─── */
.ns-kbd-grid {
  display: flex;
  flex-direction: column;
  gap: 0;
  border: 1.5px solid var(--border);
  border-radius: 16px;
  overflow: hidden;
  max-width: 620px;
}
.ns-kbd-row {
  display: flex;
  align-items: center;
  gap: 20px;
  padding: 16px 24px;
  border-bottom: 1px solid var(--border);
  background: var(--card);
  font-size: 14px;
  color: var(--text-sec);
}
.ns-kbd-row:last-child { border-bottom: none; }
.ns-kbd-keys {
  display: flex;
  align-items: center;
  gap: 5px;
  flex-shrink: 0;
  min-width: 200px;
}
kbd {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 4px 10px;
  background: var(--bg);
  border: 1.5px solid var(--border);
  border-bottom-width: 3px;
  border-radius: 6px;
  font-family: 'DM Sans', monospace;
  font-size: 12px;
  font-weight: 700;
  color: var(--text);
  white-space: nowrap;
}

/* ─── Responsive ─── */
@media (max-width: 720px) {
  .ns-seo-section { padding: 48px 16px; }
  .ns-seo-h2 { font-size: 22px; }
  .ns-seo-lead { font-size: 14px; margin-bottom: 32px; }
  .ns-steps-grid { grid-template-columns: 1fr 1fr; }
  .ns-tips-grid { grid-template-columns: 1fr; }
  .ns-diff-cards-row { grid-template-columns: 1fr 1fr; }
  .ns-features-grid { grid-template-columns: 1fr; }
  .ns-three-rules { grid-template-columns: 1fr; }
  .ns-kbd-row { gap: 12px; }
  .ns-kbd-keys { min-width: 160px; }
  .ns-diff-links-inner { gap: 6px; }
  .ns-diff-pill { padding: 5px 12px; font-size: 12px; }
}
@media (max-width: 480px) {
  .ns-steps-grid { grid-template-columns: 1fr; }
  .ns-diff-cards-row { grid-template-columns: 1fr; }
  .ns-rule-visual { padding: 24px 16px; }
}