/* =============================================================
   NUVEDA — read.css
   미리보기 페이지 — 자유 탐색 모드
   - 폰트: 리디바탕 (RIDIBatang) 본문 (전자책 가독성 최적화)
   - 배경: 종이톤보다 살짝 어두운 따뜻한 베이지 (눈 부담 감소)
   - 인터랙션: 카드 클릭 → 챕터 펼침/접힘 (자유 탐색)
   ============================================================= */


/* ──────────────────────────────────────────────
   리디바탕 웹폰트
   라이선스: SIL Open Font License 1.1
   © 리디주식회사
   ────────────────────────────────────────────── */
@font-face {
  font-family: 'Ridibatang';
  src: url('https://cdn.jsdelivr.net/gh/projectnoonnu/noonfonts_twelve@1.0/RIDIBatang.woff') format('woff');
  font-weight: normal;
  font-style: normal;
  font-display: swap;
}


/* ──────────────────────────────────────────────
   토큰 (메인과 차별화 — 더 어두운 배경, 리디바탕)
   ────────────────────────────────────────────── */
:root {
  /* 색 — 메인보다 살짝 어둡게, 따뜻한 종이톤 유지 */
  --bg:        #ebe5d6;   /* 메인 #f5f2ea 보다 한 톤 어두움 */
  --bg-soft:   #e2dcc8;   /* 섹션 강조용 */
  --bg-deeper: #d8d2bd;   /* 잠긴 카드 호버 */
  --ink:       #1c2620;
  --ink-soft:  #44504a;   /* 어두운 배경에 맞춰 살짝 진하게 */
  --green:     #2d4a3a;
  --green-d:   #1f3528;
  --muted:     #7d7569;   /* 어두운 배경에 맞춰 톤 조정 */
  --line:      #cabea8;
  --line-soft: #d9cfb6;

  /* 폰트 — 본문에 리디바탕, 라벨류에 산세리프 */
  --font-serif: 'Ridibatang', 'Noto Serif KR', 'Nanum Myeongjo', serif;
  --font-sans:  'Pretendard Variable', Pretendard, -apple-system, BlinkMacSystemFont, system-ui, sans-serif;

  --max-width: 640px;
}

* { margin: 0; padding: 0; box-sizing: border-box; }

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

body {
  font-family: var(--font-serif);
  background: var(--bg);
  color: var(--ink);
  line-height: 1.85;
  font-size: 17px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
  letter-spacing: -0.005em;

  /* 미세한 종이 질감 */
  background-image:
    radial-gradient(circle at 25% 25%, rgba(45, 74, 58, 0.020) 1px, transparent 1px),
    radial-gradient(circle at 75% 75%, rgba(45, 74, 58, 0.014) 1px, transparent 1px);
  background-size: 3px 3px, 5px 5px;
}

a { color: inherit; text-decoration: none; }
button { font-family: inherit; cursor: pointer; }


/* ──────────────────────────────────────────────
   상단 고정 헤더
   ────────────────────────────────────────────── */
.topbar {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(235, 229, 214, 0.92);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--line-soft);
}
.topbar__inner {
  max-width: 800px;
  margin: 0 auto;
  padding: 14px 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}
.topbar__brand {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-sans);
  font-size: 12px;
  font-weight: 600;
  color: var(--green);
  transition: color 0.2s ease;
}
.topbar__brand:hover {
  color: var(--green-d);
}
.topbar__logo {
  font-family: var(--font-serif);
  letter-spacing: 0.05em;
  font-weight: 500;
}
.topbar__divider {
  color: var(--muted);
  font-weight: 300;
}
.topbar__label {
  color: var(--muted);
  font-weight: 500;
  letter-spacing: 0.1em;
}


/* ──────────────────────────────────────────────
   진행도 인디케이터 (펼친 섹션 표시)
   ────────────────────────────────────────────── */
.progress {
  display: flex;
  align-items: center;
  gap: 0;
}
.progress__dot {
  display: block;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--line);
  transition: background 0.5s ease, transform 0.3s ease;
  flex-shrink: 0;
}
.progress__dot.is-active {
  background: var(--green);
  transform: scale(1.15);
}
.progress__line {
  display: block;
  width: 16px;
  height: 1px;
  background: var(--line);
  transition: background 0.6s ease;
}
.progress__line.is-active {
  background: var(--green);
}


/* ──────────────────────────────────────────────
   인트로
   ────────────────────────────────────────────── */
.intro {
  padding: 80px 24px 60px;
  text-align: center;
}
.intro__inner {
  max-width: var(--max-width);
  margin: 0 auto;
}
.intro__label {
  font-family: var(--font-sans);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.4em;
  color: var(--muted);
  text-transform: uppercase;
  margin-bottom: 20px;
}
.intro__title {
  font-family: var(--font-serif);
  font-size: 26px;
  font-weight: normal;
  color: var(--ink);
  letter-spacing: -0.02em;
  line-height: 1.5;
  margin-bottom: 18px;
}
.intro__meta {
  font-family: var(--font-sans);
  font-size: 13px;
  color: var(--muted);
  letter-spacing: 0.02em;
}


/* ──────────────────────────────────────────────
   챕터 컨테이너
   ────────────────────────────────────────────── */
.chapter {
  padding: 0 24px;
  position: relative;
}
.chapter__inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 24px 0;
}


/* ──────────────────────────────────────────────
   잠긴 카드 (클릭 가능한 button)
   ────────────────────────────────────────────── */
.chapter__locked-card {
  display: flex;
  flex-direction: column;
  align-items: center;
  width: 100%;
  background: var(--bg-soft);
  border: 1px solid var(--line);
  border-radius: 4px;
  padding: 44px 28px;
  text-align: center;
  font-family: inherit;
  cursor: pointer;
  transition: background 0.3s ease,
              border-color 0.3s ease,
              transform 0.3s ease,
              box-shadow 0.4s ease;
}
.chapter__locked-card:hover {
  background: var(--bg-deeper);
  border-color: var(--green);
  transform: translateY(-3px);
  box-shadow: 0 12px 32px rgba(28, 38, 32, 0.08);
}
.chapter__locked-card:hover .chapter__lock-cta {
  color: var(--green);
}
.chapter__lock-step {
  font-family: var(--font-sans);
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.4em;
  color: var(--muted);
  display: block;
  margin-bottom: 18px;
}
.chapter__lock-title {
  font-family: var(--font-serif);
  font-size: 26px;
  font-weight: normal;
  color: var(--ink);
  letter-spacing: -0.02em;
  display: block;
  margin-bottom: 6px;
}
.chapter__lock-desc {
  font-family: var(--font-serif);
  font-size: 15px;
  color: var(--ink-soft);
  display: block;
  margin-bottom: 24px;
}
.chapter__lock-cta {
  font-family: var(--font-sans);
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.15em;
  color: var(--muted);
  text-transform: uppercase;
  transition: color 0.3s ease;
}

/* 상태별 토글 */
.chapter--locked .chapter__head,
.chapter--locked .chapter__body,
.chapter--locked .chapter__close-area {
  display: none;
}
.chapter--open .chapter__locked-card {
  display: none;
}


/* ──────────────────────────────────────────────
   챕터 헤더 (펼침 상태)
   ────────────────────────────────────────────── */
.chapter__head {
  margin-bottom: 36px;
  padding-bottom: 28px;
  border-bottom: 1px solid var(--line-soft);
}
.chapter__step {
  font-family: var(--font-sans);
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.4em;
  color: var(--muted);
  text-transform: uppercase;
  margin-bottom: 14px;
}
.chapter__title {
  font-family: var(--font-serif);
  font-size: 28px;
  font-weight: normal;
  color: var(--ink);
  letter-spacing: -0.02em;
  line-height: 1.5;
}


/* ──────────────────────────────────────────────
   본문 — 리디바탕, 읽기 최적화
   ────────────────────────────────────────────── */
.chapter__body {
  font-family: var(--font-serif);
  font-size: 17px;
  line-height: 2;
  color: var(--ink);
}
.chapter__body p {
  margin-bottom: 24px;
  word-break: keep-all;
  overflow-wrap: break-word;
}
.chapter__body p:last-child {
  margin-bottom: 0;
}
.chapter__body strong {
  font-weight: normal;
  color: var(--green-d);
  background: linear-gradient(transparent 62%, rgba(45, 74, 58, 0.14) 62%);
  padding: 0 1px;
}


/* ──────────────────────────────────────────────
   목차 — 3단계 들여쓰기 구조
   ────────────────────────────────────────────── */
.chapter__body--toc {
  font-size: 15px;
  line-height: 1.85;
  color: var(--ink-soft);
}
.toc {
  list-style: none;
  padding: 0;
  margin: 0;
}

/* 머리말, 프롤로그, 에필로그 등 단일 라인 */
.toc__front {
  font-family: var(--font-serif);
  font-size: 16px;
  color: var(--ink);
  padding: 14px 0;
  border-bottom: 1px solid var(--line-soft);
  letter-spacing: -0.005em;
}
.toc__front:first-child {
  border-top: 1px solid var(--line-soft);
}

/* 장 단위 */
.toc__chapter {
  padding: 28px 0;
  border-bottom: 1px solid var(--line-soft);
}
.toc__chapter h3 {
  font-family: var(--font-serif);
  font-size: 18px;
  font-weight: normal;
  color: var(--ink);
  margin-bottom: 14px;
  letter-spacing: -0.01em;
}

/* 절 (1단계 들여쓰기) */
.toc__sub {
  list-style: none;
  padding: 0;
  margin: 0;
}
.toc__sub > li {
  font-family: var(--font-sans);
  font-size: 14px;
  color: var(--ink-soft);
  padding: 7px 0 7px 14px;
  position: relative;
  letter-spacing: 0;
  line-height: 1.7;
}
.toc__sub > li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 18px;
  width: 6px;
  height: 1px;
  background: var(--muted);
  opacity: 0.5;
}

/* 더 깊은 절 (2단계 들여쓰기) */
.toc__deep {
  list-style: none;
  padding: 4px 0 4px 18px;
  margin: 6px 0 4px;
}
.toc__deep li {
  font-family: var(--font-sans);
  font-size: 12.5px;
  color: var(--muted);
  padding: 4px 0;
  letter-spacing: 0;
  line-height: 1.65;
}
.toc__deep li::before {
  display: none;
}


/* ──────────────────────────────────────────────
   섹션 접기 영역
   ────────────────────────────────────────────── */
.chapter__close-area {
  margin-top: 56px;
  padding-top: 32px;
  border-top: 1px solid var(--line-soft);
  text-align: center;
}
.chapter__close {
  display: inline-block;
  font-family: var(--font-sans);
  font-size: 13px;
  font-weight: 500;
  color: var(--muted);
  background: transparent;
  border: 1px solid var(--line);
  padding: 12px 24px;
  border-radius: 999px;
  letter-spacing: 0.05em;
  transition: color 0.2s ease,
              border-color 0.2s ease,
              background 0.2s ease;
}
.chapter__close:hover {
  color: var(--green);
  border-color: var(--green);
  background: var(--bg);
}


/* ──────────────────────────────────────────────
   페이지 끝 — 구매 CTA
   ────────────────────────────────────────────── */
.end {
  padding: 100px 24px 80px;
  margin-top: 40px;
  border-top: 1px solid var(--line);
  background: var(--bg-soft);
}
.end__inner {
  max-width: var(--max-width);
  margin: 0 auto;
  text-align: center;
}
.end__message {
  font-family: var(--font-serif);
  font-size: 22px;
  line-height: 1.7;
  color: var(--ink);
  margin-bottom: 56px;
  letter-spacing: -0.01em;
}
.end__buttons {
  display: flex;
  flex-direction: column;
  gap: 10px;
  max-width: 320px;
  margin: 0 auto 48px;
}
.end__back {
  display: inline-block;
  font-family: var(--font-sans);
  font-size: 13px;
  color: var(--muted);
  letter-spacing: 0.05em;
  padding: 8px 12px;
  transition: color 0.2s ease;
}
.end__back:hover {
  color: var(--green);
}

/* 버튼 (메인과 동일 톤) */
.btn {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 18px 24px;
  font-family: var(--font-sans);
  text-decoration: none;
  border-radius: 2px;
  transition: background 0.3s ease, color 0.3s ease, transform 0.3s ease;
  border: 1px solid var(--green);
  background: transparent;
  color: var(--green);
}
.btn:hover {
  background: var(--green);
  color: var(--bg);
  transform: translateY(-1px);
}
.btn__label {
  font-size: 14px;
  font-weight: 600;
  letter-spacing: 0.02em;
}
.btn__platform {
  font-size: 12px;
  font-weight: 400;
  letter-spacing: 0.05em;
  opacity: 0.8;
}


/* ──────────────────────────────────────────────
   푸터
   ────────────────────────────────────────────── */
.read-footer {
  padding: 50px 24px 40px;
  text-align: center;
  border-top: 1px solid var(--line);
  background: var(--bg);
}
.read-footer p {
  font-family: var(--font-sans);
  font-size: 11px;
  color: var(--muted);
  margin: 4px 0;
  letter-spacing: 0.05em;
  line-height: 1.7;
}
.read-footer__font {
  font-style: italic;
  opacity: 0.8;
}


/* ──────────────────────────────────────────────
   펼침 애니메이션
   ────────────────────────────────────────────── */
@keyframes expandFadeUp {
  from { opacity: 0; transform: translateY(12px); }
  to   { opacity: 1; transform: translateY(0); }
}
.chapter--unlocking .chapter__head,
.chapter--unlocking .chapter__body,
.chapter--unlocking .chapter__close-area {
  animation: expandFadeUp 0.6s cubic-bezier(0.2, 0.6, 0.2, 1);
}


/* ──────────────────────────────────────────────
   모바일
   ────────────────────────────────────────────── */
@media (max-width: 640px) {
  .topbar__inner {
    padding: 12px 16px;
    gap: 12px;
  }
  .topbar__brand {
    font-size: 11px;
    gap: 6px;
  }
  .topbar__logo {
    letter-spacing: 0.04em;
  }
  .progress__line {
    width: 12px;
  }
  .progress__dot {
    width: 7px;
    height: 7px;
  }

  .intro {
    padding: 50px 20px 36px;
  }
  .intro__title {
    font-size: 22px;
  }

  .chapter {
    padding: 0 20px;
  }
  .chapter__inner {
    padding: 18px 0;
  }

  .chapter__locked-card {
    padding: 36px 22px;
  }
  .chapter__lock-title {
    font-size: 22px;
  }
  .chapter__lock-desc {
    font-size: 14px;
  }

  .chapter__title {
    font-size: 23px;
  }
  .chapter__head {
    margin-bottom: 28px;
    padding-bottom: 20px;
  }
  .chapter__body {
    font-size: 16px;
    line-height: 1.95;
  }
  .chapter__body p {
    margin-bottom: 20px;
  }

  /* 모바일 목차 */
  .toc__front {
    font-size: 15px;
    padding: 12px 0;
  }
  .toc__chapter {
    padding: 22px 0;
  }
  .toc__chapter h3 {
    font-size: 16px;
    margin-bottom: 12px;
  }
  .toc__sub > li {
    font-size: 13.5px;
    padding: 6px 0 6px 12px;
  }
  .toc__sub > li::before {
    top: 16px;
  }
  .toc__deep {
    padding-left: 14px;
  }
  .toc__deep li {
    font-size: 12px;
    padding: 3px 0;
  }

  .chapter__close-area {
    margin-top: 40px;
    padding-top: 24px;
  }

  .end {
    padding: 70px 20px 56px;
  }
  .end__message {
    font-size: 19px;
  }
}


/* ──────────────────────────────────────────────
   접근성: 모션 줄이기 설정 존중
   ────────────────────────────────────────────── */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}