/* 한겨레교육 출판인 AI 강의 자료 — 공통 스타일 */

:root {
  --color-bg: #fafaf9;
  --color-surface: #ffffff;
  --color-fg: #1c1917;
  --color-muted: #78716c;
  --color-subtle: #a8a29e;
  --color-border: #e7e5e4;
  --color-border-strong: #d6d3d1;

  --color-primary: #0f4c81;
  --color-primary-hover: #0a3a66;
  --color-primary-soft: #e8f0f9;

  --color-accent: #c2410c;
  --color-accent-soft: #fef3ec;
  --color-wow: #b45309;
  --color-wow-soft: #fef3c7;

  --color-success: #15803d;
  --color-success-soft: #ecfdf5;

  --color-code-bg: #f4f4f5;
  --color-table-stripe: #faf9f7;

  --shadow-sm: 0 1px 2px rgba(28, 25, 23, 0.04);
  --shadow-md: 0 4px 12px rgba(28, 25, 23, 0.06);
  --shadow-lg: 0 10px 32px rgba(28, 25, 23, 0.08);

  --max-width: 920px;
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;

  --font-sans: -apple-system, BlinkMacSystemFont, "Apple SD Gothic Neo", "Pretendard", "Noto Sans CJK KR", "Malgun Gothic", sans-serif;
  --font-mono: "SF Mono", "Menlo", "Consolas", monospace;
}

@media (prefers-color-scheme: dark) {
  :root {
    --color-bg: #0c0a09;
    --color-surface: #1c1917;
    --color-fg: #e7e5e4;
    --color-muted: #a8a29e;
    --color-subtle: #78716c;
    --color-border: #292524;
    --color-border-strong: #44403c;

    --color-primary: #60a5fa;
    --color-primary-hover: #93c5fd;
    --color-primary-soft: rgba(96, 165, 250, 0.12);

    --color-accent: #fb923c;
    --color-accent-soft: rgba(251, 146, 60, 0.10);
    --color-wow: #fbbf24;
    --color-wow-soft: rgba(251, 191, 36, 0.12);

    --color-success: #4ade80;
    --color-success-soft: rgba(74, 222, 128, 0.10);

    --color-code-bg: #18181b;
    --color-table-stripe: #18181b;

    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.4);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.5);
    --shadow-lg: 0 10px 32px rgba(0, 0, 0, 0.6);
  }
}

* { box-sizing: border-box; }

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  padding: 0;
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.7;
  color: var(--color-fg);
  background: var(--color-bg);
  word-break: keep-all;
  overflow-wrap: break-word;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

main {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 16px 20px 80px;
}

/* ────────────────────────────────────────────────────────
 * 빵 부스러기
 * ──────────────────────────────────────────────────────── */
.breadcrumb {
  font-size: 13px;
  color: var(--color-muted);
  padding: 12px 20px;
  border-bottom: 1px solid var(--color-border);
  background: rgba(250, 250, 249, 0.85);
  position: sticky;
  top: 0;
  z-index: 10;
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
}

@media (prefers-color-scheme: dark) {
  .breadcrumb { background: rgba(12, 10, 9, 0.85); }
}

.breadcrumb-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 8px;
}

.breadcrumb a {
  color: var(--color-muted);
  text-decoration: none;
  transition: color 0.15s;
}

.breadcrumb a:hover {
  color: var(--color-primary);
}

.breadcrumb .sep {
  color: var(--color-subtle);
  font-size: 14px;
}

.breadcrumb .current {
  color: var(--color-fg);
  font-weight: 500;
}

.breadcrumb .badge {
  display: inline-block;
  padding: 2px 8px;
  background: var(--color-primary-soft);
  color: var(--color-primary);
  border-radius: 999px;
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.02em;
  margin-right: 4px;
}

/* ────────────────────────────────────────────────────────
 * Hero
 * ──────────────────────────────────────────────────────── */
.hero {
  margin: 24px 0 32px;
  padding: 36px 32px;
  border-radius: var(--radius-lg);
  position: relative;
  overflow: hidden;
}

.hero-index {
  background: linear-gradient(135deg, var(--color-primary-soft) 0%, var(--color-accent-soft) 100%);
  border: 1px solid var(--color-border);
}

.hero-curriculum {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  box-shadow: var(--shadow-sm);
}

.hero-lesson {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  box-shadow: var(--shadow-sm);
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 24px;
  align-items: center;
  padding: 28px 32px;
}

.hero-lesson.is-wow {
  background: linear-gradient(135deg, var(--color-wow-soft) 0%, var(--color-accent-soft) 100%);
  border-color: var(--color-wow);
}

.hero-badge {
  display: inline-block;
  padding: 4px 12px;
  background: var(--color-surface);
  color: var(--color-primary);
  border: 1px solid var(--color-border);
  border-radius: 999px;
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.02em;
  margin-bottom: 12px;
}

.hero-lesson.is-wow .hero-badge {
  color: var(--color-wow);
  border-color: var(--color-wow);
}

.wow-mark {
  margin-left: 8px;
  font-size: 11px;
  color: var(--color-wow);
  font-weight: 700;
}

.hero-title {
  margin: 0 0 8px;
  font-size: 32px;
  font-weight: 800;
  line-height: 1.2;
  letter-spacing: -0.025em;
  color: var(--color-fg);
}

.hero-lesson .hero-title {
  font-size: 22px;
  font-weight: 700;
}

.hero-subtitle {
  font-size: 16px;
  color: var(--color-muted);
  margin-bottom: 16px;
  line-height: 1.5;
}

.hero-lesson .hero-subtitle { display: none; }

.hero-spec {
  display: inline-block;
  padding: 6px 14px;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  font-size: 13px;
  color: var(--color-muted);
  font-family: var(--font-mono);
  font-feature-settings: "tnum";
}

.hero-number {
  font-size: 64px;
  font-weight: 800;
  line-height: 1;
  color: var(--color-primary);
  letter-spacing: -0.04em;
  font-feature-settings: "tnum";
  opacity: 0.85;
}

.hero-lesson.is-wow .hero-number {
  color: var(--color-wow);
  opacity: 1;
}

/* ────────────────────────────────────────────────────────
 * 본문 콘텐츠
 * ──────────────────────────────────────────────────────── */
.content h1,
.content h2,
.content h3,
.content h4 {
  letter-spacing: -0.015em;
}

.content h2 {
  font-size: 24px;
  font-weight: 700;
  line-height: 1.3;
  margin: 48px 0 16px;
  padding-bottom: 10px;
  border-bottom: 2px solid var(--color-border);
}

.content h2:first-child {
  margin-top: 16px;
}

.content h3 {
  font-size: 19px;
  font-weight: 600;
  margin: 32px 0 12px;
  color: var(--color-fg);
}

.content h3::before {
  content: "";
  display: inline-block;
  width: 4px;
  height: 16px;
  background: var(--color-primary);
  border-radius: 2px;
  margin-right: 10px;
  vertical-align: -2px;
}

.content h4 {
  font-size: 16px;
  font-weight: 600;
  margin: 24px 0 8px;
  color: var(--color-fg);
}

.content p {
  margin: 0 0 16px;
}

/* 링크 */
.content a {
  color: var(--color-primary);
  text-decoration: underline;
  text-underline-offset: 3px;
  text-decoration-thickness: 1px;
  text-decoration-color: var(--color-border-strong);
  transition: text-decoration-color 0.15s, color 0.15s;
}

.content a:hover {
  color: var(--color-primary-hover);
  text-decoration-color: var(--color-primary);
}

.content strong {
  font-weight: 700;
}

/* 리스트 */
.content ul,
.content ol {
  margin: 0 0 16px;
  padding-left: 24px;
}

.content li {
  margin: 6px 0;
}

.content li > ul,
.content li > ol {
  margin: 6px 0;
}

.content li::marker {
  color: var(--color-muted);
}

/* 인용·박스 */
.content blockquote {
  margin: 20px 0;
  padding: 18px 22px;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-left: 4px solid var(--color-primary);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-sm);
}

.content blockquote > :last-child {
  margin-bottom: 0;
}

.content blockquote strong {
  color: var(--color-primary);
}

/* 표 */
.content table {
  width: 100%;
  border-collapse: collapse;
  margin: 20px 0;
  font-size: 14px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  overflow: hidden;
  background: var(--color-surface);
}

.content table thead {
  background: var(--color-primary-soft);
}

.content table th {
  padding: 10px 14px;
  text-align: left;
  font-weight: 600;
  color: var(--color-primary);
  border-bottom: 2px solid var(--color-border);
  font-size: 13px;
  letter-spacing: 0.01em;
}

.content table td {
  padding: 10px 14px;
  border-bottom: 1px solid var(--color-border);
  vertical-align: top;
}

.content table tbody tr:nth-child(even) {
  background: var(--color-table-stripe);
}

.content table tbody tr:last-child td {
  border-bottom: none;
}

.content table tbody tr:hover {
  background: var(--color-primary-soft);
}

/* 코드 */
.content code {
  background: var(--color-code-bg);
  padding: 2px 6px;
  border-radius: var(--radius-sm);
  font-family: var(--font-mono);
  font-size: 0.875em;
  color: var(--color-accent);
}

.content pre {
  background: var(--color-code-bg);
  padding: 16px 18px;
  border-radius: var(--radius-md);
  overflow-x: auto;
  border: 1px solid var(--color-border);
  margin: 18px 0;
}

.content pre code {
  background: none;
  padding: 0;
  color: var(--color-fg);
  font-size: 13px;
  line-height: 1.6;
}

/* 수평선 */
.content hr {
  border: none;
  border-top: 1px solid var(--color-border);
  margin: 40px 0;
}

/* ────────────────────────────────────────────────────────
 * 회차 이전/다음
 * ──────────────────────────────────────────────────────── */
.lesson-nav {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
  margin: 40px 0 0;
}

.lesson-nav a {
  display: block;
  padding: 16px 18px;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  text-decoration: none;
  transition: border-color 0.15s, transform 0.15s, box-shadow 0.15s;
}

.lesson-nav a:hover {
  border-color: var(--color-primary);
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}

.lesson-nav .label {
  display: block;
  font-size: 11px;
  color: var(--color-muted);
  margin-bottom: 4px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  font-weight: 600;
}

.lesson-nav .title {
  font-weight: 500;
  font-size: 14px;
  color: var(--color-fg);
  line-height: 1.45;
}

.lesson-nav .next {
  text-align: right;
}

.lesson-nav a.disabled {
  opacity: 0.4;
  pointer-events: none;
}

/* ────────────────────────────────────────────────────────
 * 다음 단계 (계층 전파)
 * ──────────────────────────────────────────────────────── */
.next-step {
  margin: 48px 0 0;
  padding: 28px;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
}

.next-step-title {
  font-size: 12px;
  font-weight: 700;
  color: var(--color-muted);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-bottom: 16px;
}

.next-step-links {
  display: grid;
  gap: 10px;
}

.step-card {
  display: block;
  padding: 16px 18px;
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  text-decoration: none;
  color: var(--color-fg);
  transition: border-color 0.15s, transform 0.15s, box-shadow 0.15s;
  position: relative;
}

.step-card:hover {
  border-color: var(--color-primary);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.step-card strong {
  display: inline-block;
  font-weight: 600;
  color: var(--color-fg);
  margin-bottom: 4px;
}

.step-card .step-arrow {
  display: inline-block;
  color: var(--color-primary);
  margin-right: 8px;
  font-weight: 600;
  transition: transform 0.15s;
}

.step-card:hover .step-arrow {
  transform: translateX(2px);
}

.step-card .desc {
  display: block;
  color: var(--color-muted);
  font-size: 13px;
  margin-top: 6px;
  line-height: 1.5;
}

/* 회차 카드 (커리큘럼 페이지 하단) */
.lesson-grid {
  grid-template-columns: 1fr;
  gap: 10px;
}

@media (min-width: 600px) {
  .lesson-grid {
    grid-template-columns: 1fr 1fr;
  }
}

.lesson-card {
  display: grid;
  grid-template-columns: 48px 1fr;
  gap: 16px;
  align-items: center;
  padding: 18px 20px;
}

.lesson-card-num {
  font-size: 32px;
  font-weight: 800;
  line-height: 1;
  color: var(--color-primary);
  font-feature-settings: "tnum";
  letter-spacing: -0.02em;
  opacity: 0.7;
}

.lesson-card.is-wow {
  border-color: var(--color-wow);
  background: linear-gradient(135deg, var(--color-wow-soft) 0%, var(--color-bg) 60%);
}

.lesson-card.is-wow .lesson-card-num {
  color: var(--color-wow);
  opacity: 1;
}

.lesson-card-body {
  min-width: 0;
}

.lesson-card-body strong {
  margin-bottom: 0;
  font-size: 15px;
}

.lesson-card-sub {
  color: var(--color-muted);
  font-size: 14px;
  font-weight: 400;
}

.wow-tag {
  display: inline-block;
  color: var(--color-wow);
  margin-left: 4px;
  font-weight: 700;
}

/* ────────────────────────────────────────────────────────
 * 푸터
 * ──────────────────────────────────────────────────────── */
.page-footer {
  margin-top: 56px;
  padding-top: 24px;
  border-top: 1px solid var(--color-border);
  text-align: center;
  color: var(--color-muted);
  font-size: 12px;
}

.footer-brand {
  font-weight: 600;
  color: var(--color-fg);
  margin-bottom: 8px;
  font-size: 13px;
}

.footer-links {
  font-size: 12px;
}

.footer-links a {
  color: var(--color-muted);
  text-decoration: none;
  margin: 0 4px;
  transition: color 0.15s;
}

.footer-links a:hover {
  color: var(--color-primary);
}

/* ────────────────────────────────────────────────────────
 * 프린트
 * ──────────────────────────────────────────────────────── */
@media print {
  body { background: white; color: black; }
  .breadcrumb, .next-step, .lesson-nav { display: none; }
  main { max-width: none; padding: 0; }
  .hero {
    background: white !important;
    border: 1px solid #ccc;
    box-shadow: none;
    page-break-after: avoid;
  }
  .content a { color: black; text-decoration: none; }
}

/* ────────────────────────────────────────────────────────
 * 모바일
 * ──────────────────────────────────────────────────────── */
@media (max-width: 640px) {
  main { padding: 12px 14px 60px; }
  .hero { padding: 24px 20px; }
  .hero-title { font-size: 24px; }
  .hero-lesson { padding: 20px; grid-template-columns: auto 1fr; gap: 16px; }
  .hero-number { font-size: 48px; }
  .hero-lesson .hero-title { font-size: 18px; }
  .content h2 { font-size: 20px; }
  .content h3 { font-size: 17px; }
  .content table { font-size: 13px; }
  .content table th,
  .content table td { padding: 8px 10px; }
  .lesson-nav { grid-template-columns: 1fr; }
  .next-step { padding: 20px; }
  .lesson-card { grid-template-columns: 36px 1fr; gap: 12px; padding: 14px 16px; }
  .lesson-card-num { font-size: 24px; }
}