/* ==========================================================================
   AI 블로그 수익화 시스템 — 전자책 판매 랜딩페이지
   DESIGN-meta.md 토큰을 CSS Custom Properties로 매핑하여 전체 스타일에서 사용한다.
   ========================================================================== */

:root {
  /* Colors */
  --color-primary: #0064e0;
  --color-primary-deep: #0457cb;
  --color-on-primary: #ffffff;
  --color-ink-button: #000000;
  --color-canvas: #ffffff;
  --color-surface-soft: #f1f4f7;
  --color-ink-deep: #0a1317;
  --color-ink: #1c1e21;
  --color-charcoal: #444950;
  --color-steel: #5d6c7b;
  --color-stone: #8595a4;
  --color-hairline-soft: #dee3e9;
  --color-success: #31a24c;
  --color-warning: #f7b928;

  /* Typography */
  --font-family-base: "Optimistic VF", Montserrat, Helvetica, Arial, "Noto Sans", "Noto Sans KR", sans-serif;

  /* Radius */
  --radius-full: 100px;
  --radius-xl: 16px;
  --radius-xxxl: 32px;
  --radius-circle: 9999px;

  /* Spacing */
  --spacing-xxs: 4px;
  --spacing-xs: 8px;
  --spacing-sm: 10px;
  --spacing-md: 12px;
  --spacing-base: 16px;
  --spacing-lg: 20px;
  --spacing-xl: 24px;
  --spacing-xxl: 32px;
  --spacing-xxxl: 40px;
  --spacing-section-sm: 48px;
  --spacing-section: 64px;
  --spacing-section-lg: 80px;

  /* Elevation */
  --shadow-level-2: rgba(20, 22, 26, 0.3) 0px 1px 4px 0px;

  /* Layout */
  --container-max-width: 1280px;
  --promo-banner-height: 44px;
  --site-header-height: 64px;
}

/* ---------------------------------------------------------------------- */
/* Reset / base                                                            */
/* ---------------------------------------------------------------------- */

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  .fade-in-up {
    animation: none;
  }
}

@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(16px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.fade-in-up {
  animation: fadeInUp 0.6s ease-out both;
}

.fade-in-up--delay {
  animation-delay: 0.15s;
}

body {
  margin: 0;
  font-family: var(--font-family-base);
  color: var(--color-ink);
  background-color: var(--color-canvas);
  -webkit-font-smoothing: antialiased;
  word-break: keep-all;
  overflow-wrap: break-word;
}

ul {
  list-style: none;
  margin: 0;
  padding: 0;
}

h1, h2, h3, p {
  margin: 0;
}

a {
  color: inherit;
  text-decoration: none;
}

img, svg {
  display: block;
  max-width: 100%;
}

.container {
  max-width: var(--container-max-width);
  margin: 0 auto;
  padding: 0 var(--spacing-xxl);
}

/* ---------------------------------------------------------------------- */
/* Typography utility classes (typography.* 토큰)                          */
/* ---------------------------------------------------------------------- */

.type-hero-display {
  font-size: 64px;
  font-weight: 500;
  line-height: 1.16;
}

.type-display-lg {
  font-size: 48px;
  font-weight: 500;
  line-height: 1.17;
}

.type-heading-lg {
  font-size: 36px;
  font-weight: 500;
  line-height: 1.28;
}

.type-heading-sm {
  font-size: 24px;
  font-weight: 500;
  line-height: 1.25;
}

.type-subtitle-lg {
  font-size: 18px;
  font-weight: 700;
  line-height: 1.44;
}

.type-subtitle-md {
  font-size: 18px;
  font-weight: 400;
  line-height: 1.44;
}

.type-body-md-bold {
  font-size: 16px;
  font-weight: 700;
  line-height: 1.50;
  letter-spacing: -0.16px;
}

.type-body-md {
  font-size: 16px;
  font-weight: 400;
  line-height: 1.50;
  letter-spacing: -0.16px;
}

.type-body-sm-bold {
  font-size: 14px;
  font-weight: 700;
  line-height: 1.43;
  letter-spacing: -0.14px;
}

.type-body-sm {
  font-size: 14px;
  font-weight: 400;
  line-height: 1.43;
  letter-spacing: -0.14px;
}

.type-caption-bold {
  font-size: 12px;
  font-weight: 700;
  line-height: 1.33;
}

.type-caption {
  font-size: 12px;
  font-weight: 400;
  line-height: 1.33;
}

.type-button-md {
  font-size: 14px;
  font-weight: 700;
  line-height: 1.43;
  letter-spacing: -0.14px;
}

/* ---------------------------------------------------------------------- */
/* Buttons                                                                  */
/* ---------------------------------------------------------------------- */

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 14px;
  font-weight: 700;
  line-height: 1.43;
  letter-spacing: -0.14px;
  border-radius: var(--radius-full);
  padding: 14px 30px;
  border: none;
  cursor: pointer;
  white-space: nowrap;
  transition: filter 0.2s ease;
}

.button:hover {
  filter: brightness(1.1);
}

/* 이 랜딩은 전체가 구매 유도 목적이므로 CTA는 전부 button-buy-cta(코발트)로 통일 */
.button-buy-cta {
  background-color: var(--color-primary);
  color: var(--color-on-primary);
}

.button-buy-cta:active {
  background-color: var(--color-primary-deep);
}

.button-secondary {
  background-color: transparent;
  color: var(--color-ink-deep);
  border: 2px solid var(--color-ink-deep);
  padding: 12px 28px;
}

.button--tap-scale {
  transition: filter 0.2s ease, transform 0.15s ease;
}

.button--tap-scale:active,
.button--tap-scale.is-pressed {
  transform: scale(0.96);
}

/* ---------------------------------------------------------------------- */
/* Badges                                                                   */
/* ---------------------------------------------------------------------- */

.badge {
  display: inline-flex;
  align-items: center;
  font-size: 12px;
  font-weight: 700;
  line-height: 1.33;
  border-radius: var(--radius-full);
  padding: 4px 10px;
}

.badge-promo-yellow {
  background-color: var(--color-warning);
  color: var(--color-ink-deep);
}

.badge-success {
  background-color: var(--color-success);
  color: var(--color-canvas);
}

/* ---------------------------------------------------------------------- */
/* Cards                                                                    */
/* ---------------------------------------------------------------------- */

.card {
  background-color: var(--color-canvas);
}

.card-icon-feature {
  border-radius: var(--radius-xl);
  padding: var(--spacing-xl);
  border: 1px solid var(--color-hairline-soft);
}

.card-product-feature {
  border-radius: var(--radius-xxxl);
  padding: var(--spacing-xxl);
  border: 1px solid var(--color-hairline-soft);
}

.testimonial-customer-card {
  border-radius: var(--radius-xl);
  padding: var(--spacing-xxl);
  border: 1px solid var(--color-hairline-soft);
  color: var(--color-ink);
}

.card-checkout-summary {
  border-radius: var(--radius-xl);
  padding: var(--spacing-xl);
  border: 1px solid var(--color-hairline-soft);
  box-shadow: var(--shadow-level-2);
}

.icon-chip {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  color: var(--color-ink-deep);
  margin-bottom: var(--spacing-base);
}

/* ---------------------------------------------------------------------- */
/* 2.1 프로모 배너                                                          */
/* ---------------------------------------------------------------------- */

.promo-banner {
  position: sticky;
  top: 0;
  z-index: 60;
  background-color: var(--color-warning);
  color: var(--color-ink-deep);
  padding: var(--spacing-md) var(--spacing-xl);
  height: var(--promo-banner-height);
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
}

.promo-banner__text {
  margin: 0;
  display: flex;
  align-items: center;
  gap: var(--spacing-xs);
  max-width: 100%;
  overflow: hidden;
  white-space: nowrap;
  text-overflow: ellipsis;
}

.promo-banner__link {
  text-decoration: underline;
  flex-shrink: 0;
}

/* ---------------------------------------------------------------------- */
/* 2.2 헤더                                                                 */
/* ---------------------------------------------------------------------- */

.site-header {
  position: sticky;
  top: var(--promo-banner-height);
  z-index: 50;
  background-color: var(--color-canvas);
  border-bottom: 1px solid var(--color-hairline-soft);
  height: var(--site-header-height);
}

.site-header__inner {
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.site-header__logo {
  color: var(--color-ink-deep);
}

.site-header__cta {
  padding: 10px 22px;
}

/* ---------------------------------------------------------------------- */
/* 2.3 히어로                                                               */
/* ---------------------------------------------------------------------- */

.hero {
  display: grid;
  grid-template-columns: 3fr 2fr;
  align-items: center;
  gap: var(--spacing-section);
  min-height: 100vh;
  padding-top: var(--spacing-section-lg);
  padding-bottom: var(--spacing-section-lg);
}

.hero__copy {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: var(--spacing-base);
}

.hero__title {
  color: var(--color-ink-deep);
}

.hero__subtitle {
  color: var(--color-ink);
}

.hero__trust {
  display: flex;
  align-items: center;
  gap: var(--spacing-xxs);
  color: var(--color-steel);
}

.hero__trust-star {
  color: var(--color-warning);
}

.hero__trust-divider {
  color: var(--color-stone);
}

.hero__ctas {
  display: flex;
  flex-direction: row;
  gap: var(--spacing-base);
  margin-top: var(--spacing-base);
}

.hero__media {
  display: flex;
  justify-content: center;
}

.book-cover {
  width: 100%;
  max-width: 340px;
  aspect-ratio: 3 / 4;
  border-radius: var(--radius-xxxl);
  background: linear-gradient(145deg, var(--color-primary) 0%, var(--color-ink-deep) 100%);
  color: var(--color-on-primary);
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  justify-content: space-between;
  padding: var(--spacing-xxl);
}

.book-cover--placeholder {
  max-width: 300px;
}

.book-cover__badge {
  background-color: rgba(255, 255, 255, 0.16);
  color: var(--color-on-primary);
  border-radius: var(--radius-full);
  padding: 4px 10px;
}

.book-cover__title {
  color: var(--color-on-primary);
}

.book-cover__author {
  color: rgba(255, 255, 255, 0.8);
}

/* ---------------------------------------------------------------------- */
/* 2.35 목차                                                               */
/* ---------------------------------------------------------------------- */

#toc {
  scroll-margin-top: calc(var(--promo-banner-height) + var(--site-header-height));
}

.toc {
  padding: var(--spacing-section-lg) 0;
}

.toc h2 {
  color: var(--color-ink-deep);
  text-align: center;
  margin-bottom: var(--spacing-xs);
}

.toc__lead {
  color: var(--color-steel);
  text-align: center;
  margin-bottom: var(--spacing-xxl);
}

/* 그리드 배치는 Tailwind 유틸리티(grid grid-cols-1 md:grid-cols-3 gap-8)로 처리 */

.toc-part__index {
  display: inline-block;
  color: var(--color-primary);
  margin-bottom: var(--spacing-xs);
}

.toc-part__title {
  color: var(--color-ink-deep);
  margin-bottom: var(--spacing-base);
}

.toc-part__chapters {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-sm);
}

.toc-part__chapter {
  color: var(--color-charcoal);
  padding-left: var(--spacing-base);
  position: relative;
}

.toc-part__chapter::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.6em;
  width: 4px;
  height: 4px;
  border-radius: var(--radius-circle);
  background-color: var(--color-stone);
}

/* ---------------------------------------------------------------------- */
/* 2.4 핵심 혜택 3가지                                                      */
/* ---------------------------------------------------------------------- */

.benefits {
  padding: var(--spacing-section-lg) 0;
}

.benefits h2 {
  color: var(--color-ink-deep);
  text-align: center;
  margin-bottom: var(--spacing-xxl);
}

/* 그리드 배치는 Tailwind 유틸리티(grid grid-cols-1 md:grid-cols-2 lg:grid-cols-3 gap-8)로 처리 */

.benefits__grid .card-icon-feature h3 {
  color: var(--color-ink-deep);
  margin-bottom: var(--spacing-xs);
}

.benefits__grid .card-icon-feature p {
  color: var(--color-charcoal);
}

/* ---------------------------------------------------------------------- */
/* 2.5 저자 소개                                                            */
/* ---------------------------------------------------------------------- */

.author {
  padding: var(--spacing-section) 0;
}

.author__section-title {
  color: var(--color-ink-deep);
  text-align: center;
  margin-bottom: var(--spacing-xxl);
}

.author__card {
  display: flex;
  align-items: center;
  gap: var(--spacing-xxl);
}

.author__avatar {
  flex-shrink: 0;
  width: 112px;
  height: 112px;
  border-radius: var(--radius-circle);
  background: linear-gradient(145deg, var(--color-steel) 0%, var(--color-ink-deep) 100%);
  color: var(--color-canvas);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 40px;
  font-weight: 500;
}

.author__body h3 {
  color: var(--color-ink-deep);
  margin-bottom: var(--spacing-base);
}

.author__body p {
  color: var(--color-ink);
  margin-bottom: 0;
}

/* ---------------------------------------------------------------------- */
/* 2.6 독자 후기                                                            */
/* ---------------------------------------------------------------------- */

.testimonials {
  background-color: var(--color-surface-soft);
  padding: var(--spacing-section) 0;
}

.testimonials h2 {
  color: var(--color-ink-deep);
  text-align: center;
  margin-bottom: var(--spacing-xxl);
}

.testimonials__grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--spacing-xl);
}

.testimonial-customer-card {
  background-color: var(--color-canvas);
}

.star-rating {
  color: var(--color-warning);
  font-size: 14px;
  letter-spacing: 2px;
  margin-bottom: var(--spacing-xs);
}

.testimonial-customer-card__head {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  margin-bottom: var(--spacing-base);
}

.testimonial-customer-card__role {
  color: var(--color-steel);
}

.avatar-sm {
  flex-shrink: 0;
  width: 40px;
  height: 40px;
  border-radius: var(--radius-circle);
  background: linear-gradient(145deg, var(--color-steel) 0%, var(--color-ink-deep) 100%);
  color: var(--color-canvas);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 14px;
  font-weight: 700;
}

/* ---------------------------------------------------------------------- */
/* 2.8 가격 및 최종 구매 CTA                                                */
/* ---------------------------------------------------------------------- */

.pricing {
  padding: var(--spacing-section-lg) 0;
}

.pricing__container {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
}

.pricing h2 {
  color: var(--color-ink-deep);
  margin-bottom: var(--spacing-xxl);
}

.pricing__card {
  width: 100%;
  max-width: 480px;
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
}

.pricing__off-badge {
  margin-bottom: var(--spacing-base);
}

.pricing__original {
  color: var(--color-stone);
  text-decoration: line-through;
  margin-bottom: var(--spacing-xxs);
}

.pricing__discounted {
  color: var(--color-ink-deep);
  margin-bottom: var(--spacing-xl);
}

.pricing__benefits {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-sm);
  margin-bottom: var(--spacing-xl);
  color: var(--color-ink);
}

.pricing__benefits li {
  display: flex;
  align-items: center;
  gap: var(--spacing-xs);
  justify-content: center;
}

.pricing__check {
  color: var(--color-success);
  font-weight: 700;
}

.pricing__risk {
  color: var(--color-steel);
  margin-bottom: var(--spacing-lg);
}

.pricing__cta {
  width: 100%;
  margin-bottom: var(--spacing-sm);
}

.pricing__note {
  color: var(--color-steel);
}

.pricing__share {
  width: 100%;
  max-width: calc(480px - (var(--spacing-xl) * 2) - 2px);
  margin-top: var(--spacing-xxl);
}

/* ---------------------------------------------------------------------- */
/* 2.7 FAQ                                                                  */
/* ---------------------------------------------------------------------- */

.faq {
  padding: var(--spacing-section) 0;
}

.faq h2 {
  color: var(--color-ink-deep);
  text-align: center;
  margin-bottom: var(--spacing-xxl);
}

.faq-accordion {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-xxl);
  max-width: 760px;
  margin: 0 auto;
}

.faq-accordion-item {
  background-color: var(--color-canvas);
  border-radius: var(--radius-xl);
  padding: var(--spacing-xl);
  border: 1px solid var(--color-hairline-soft);
}

.faq-accordion-item summary {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--spacing-base);
  cursor: pointer;
  color: var(--color-ink-deep);
  list-style: none;
}

.faq-accordion-item summary::-webkit-details-marker {
  display: none;
}

.faq-accordion-item__chevron {
  flex-shrink: 0;
  color: var(--color-steel);
  transition: transform 0.2s ease-in-out;
}

.faq-accordion-item[open] .faq-accordion-item__chevron {
  transform: rotate(180deg);
}

.faq-accordion-item__answer {
  color: var(--color-ink);
  padding-top: var(--spacing-base);
}

/* ---------------------------------------------------------------------- */
/* 2.9 미니 푸터                                                            */
/* ---------------------------------------------------------------------- */

.footer-region {
  background-color: var(--color-canvas);
  border-top: 1px solid var(--color-hairline-soft);
  padding: var(--spacing-section) 0;
}

.footer-region__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--spacing-base);
  color: var(--color-steel);
}

.footer-region__inner p {
  color: var(--color-steel);
  margin: 0;
}

.footer-region__links a {
  text-decoration: underline;
}

/* ---------------------------------------------------------------------- */
/* 모바일 하단 sticky CTA 바 (페이지 전체 1개)                              */
/* ---------------------------------------------------------------------- */

.sticky-mobile-cta {
  display: none;
  position: fixed;
  left: 0;
  right: 0;
  bottom: 0;
  z-index: 70;
  align-items: center;
  justify-content: space-between;
  gap: var(--spacing-base);
  background-color: var(--color-canvas);
  border-top: 1px solid var(--color-hairline-soft);
  box-shadow: var(--shadow-level-2);
  padding: var(--spacing-base) var(--spacing-xl);
  transform: translateY(100%);
  transition: transform 0.2s ease-in-out;
}

.sticky-mobile-cta.is-visible {
  transform: translateY(0);
}

.sticky-mobile-cta__label {
  color: var(--color-steel);
  margin-bottom: 2px;
}

.sticky-mobile-cta__price {
  color: var(--color-ink-deep);
}

.sticky-mobile-cta__button {
  flex-shrink: 0;
  padding: 12px 22px;
}

/* ==========================================================================
   Responsive Behavior — 480 / 768 / 1024 / 1360px (DESIGN-meta.md 기준)
   ========================================================================== */

/* Wide Desktop ≥ 1360px : 넓은 히어로 거터 */
@media (min-width: 1360px) {
  .container {
    padding-left: var(--spacing-xxxl);
    padding-right: var(--spacing-xxxl);
  }
}

/* < 1024px : 히어로 2컬럼 비중 축소 (텍스트 우선, 이미지 축소) */
@media (max-width: 1023px) {
  .hero {
    gap: var(--spacing-xxl);
  }

  .book-cover {
    max-width: 280px;
  }
}

/* Mobile < 768px */
@media (max-width: 767px) {
  .container {
    padding-left: var(--spacing-xl);
    padding-right: var(--spacing-xl);
  }

  /* 헤더: 로고+버튼 2요소 유지, 로고만 축소 */
  .site-header__logo {
    font-size: 14px;
    font-weight: 700;
    line-height: 1.43;
    letter-spacing: -0.14px;
  }

  /* 히어로: 이미지가 텍스트 위로 stack, 타이포 축소, 높이는 콘텐츠에 맞춰 auto */
  .hero {
    grid-template-columns: 1fr;
    min-height: auto;
    padding-top: var(--spacing-section);
    padding-bottom: var(--spacing-section);
  }

  .hero__media {
    order: -1;
  }

  .hero__title {
    font-size: 36px;
    line-height: 1.28;
  }

  .hero__ctas {
    flex-direction: column;
    align-items: stretch;
    width: 100%;
  }

  .hero__ctas .button {
    width: 100%;
  }

  /* 후기 그리드: 1-up 스택 (혜택 그리드는 Tailwind grid-cols-1이 처리) */
  .testimonials__grid {
    grid-template-columns: 1fr;
  }

  .benefits__grid .card-icon-feature {
    padding: var(--spacing-xl);
  }

  /* 저자 소개: 이미지 상단 중앙, 텍스트 세로 스택 */
  .author__card {
    flex-direction: column;
    text-align: center;
  }

  /* 푸터: 중앙 정렬 세로 스택 */
  .footer-region__inner {
    flex-direction: column;
    text-align: center;
  }

  /* 모바일 하단 sticky CTA 바 노출 시작 */
  .sticky-mobile-cta {
    display: flex;
  }

  /* sticky 바에 가려지지 않도록 본문 하단 여백 확보 */
  main {
    padding-bottom: 88px;
  }
}

/* Mobile (small) < 480px */
@media (max-width: 479px) {
  .hero__title {
    font-size: 28px;
  }

  .book-cover {
    max-width: 220px;
  }

  .pricing__discounted {
    font-size: 36px;
  }
}