/* 소개 랜딩 + 기능 상세 페이지 공통 */
html {
  scroll-behavior: smooth;
}

.landing-page {
  position: relative;
  z-index: 1;
  max-width: 800px;
  margin: 0 auto;
  padding: 0 16px 56px;
}

/* ── 상단 네비 ── */
.landing-nav {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 14px 4px;
  margin-bottom: 8px;
  background: rgba(240, 247, 255, 0.92);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid rgba(221, 234, 248, 0.8);
}

.landing-nav-brand {
  display: flex;
  align-items: center;
  gap: 8px;
  text-decoration: none;
  color: var(--navy);
}

.landing-nav-icon {
  font-size: 28px;
  line-height: 1;
}

.landing-nav-title {
  font-family: 'Cinzel', serif;
  font-size: 15px;
  letter-spacing: 2px;
  font-weight: 600;
}

.landing-nav-login {
  display: inline-flex;
  align-items: center;
  padding: 8px 16px;
  border-radius: 10px;
  border: 1px solid rgba(37, 99, 235, 0.35);
  background: #ffffff;
  color: var(--navy);
  font-size: 13px;
  font-weight: 600;
  text-decoration: none;
  font-family: inherit;
  transition: background 0.15s, border-color 0.15s;
  white-space: nowrap;
}

.landing-nav-login:hover {
  background: rgba(37, 99, 235, 0.08);
  border-color: var(--blue);
}

/* ── 히어로 ── */
.landing-hero {
  text-align: center;
  padding: 28px 8px 32px;
}

.landing-hero-icon {
  font-size: 52px;
  display: block;
  margin-bottom: 12px;
  animation: float 3s ease-in-out infinite;
}

.landing-headline {
  font-family: 'Noto Serif KR', serif;
  font-size: clamp(22px, 5.5vw, 30px);
  font-weight: 700;
  color: var(--navy);
  line-height: 1.45;
  margin-bottom: 14px;
}

.landing-tagline {
  font-size: 15px;
  color: #4a6a94;
  line-height: 1.7;
  max-width: 560px;
  margin: 0 auto;
}

/* ── 기능 카드 그리드 ── */
.landing-section-label {
  font-family: 'Noto Serif KR', serif;
  font-size: 18px;
  color: var(--navy);
  text-align: center;
  margin-bottom: 16px;
}

.landing-features-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 12px;
  margin-bottom: 32px;
}

.landing-feature-link {
  display: block;
  text-decoration: none;
  color: inherit;
  height: 100%;
  border-radius: 14px;
  transition: transform 0.15s, box-shadow 0.15s;
}

.landing-feature-link:hover {
  transform: translateY(-2px);
}

.landing-feature-link:focus-visible {
  outline: 2px solid var(--blue);
  outline-offset: 2px;
}

.landing-feature-card {
  background: #ffffff;
  border: 1px solid #ddeaf8;
  border-radius: 14px;
  padding: 18px 14px;
  text-align: center;
  height: 100%;
  box-shadow: 0 4px 16px rgba(74, 144, 226, 0.06);
  transition: border-color 0.15s, box-shadow 0.15s;
}

.landing-feature-link:hover .landing-feature-card {
  border-color: rgba(37, 99, 235, 0.35);
  box-shadow: 0 8px 24px rgba(37, 99, 235, 0.12);
}

.landing-feature-icon {
  font-size: 28px;
  display: block;
  margin-bottom: 10px;
}

.landing-feature-title {
  font-size: 14px;
  font-weight: 600;
  color: var(--navy);
  line-height: 1.35;
  margin-bottom: 6px;
}

.landing-feature-desc {
  font-size: 12px;
  color: #8a9eb8;
  line-height: 1.55;
}

.landing-feature-more {
  display: inline-block;
  margin-top: 8px;
  font-size: 11px;
  color: var(--blue);
  font-weight: 500;
}

/* ── 단어 미리보기 (index) ── */
.landing-vocab-section {
  background: #ffffff;
  border: 1px solid #ddeaf8;
  border-radius: 20px;
  padding: 24px 18px;
  margin-bottom: 28px;
  box-shadow: 0 4px 20px rgba(74, 144, 226, 0.08);
}

.landing-vocab-section-title {
  font-family: 'Noto Serif KR', serif;
  font-size: 18px;
  color: var(--navy);
  text-align: center;
  margin-bottom: 6px;
}

.landing-vocab-desc {
  text-align: center;
  font-size: 12px;
  color: var(--gray);
  margin-bottom: 18px;
}

/* ── 오늘의 픽 인터랙티브 카드 ── */
.vocab-pick-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 12px;
  margin-bottom: 22px;
}

.vocab-pick-wrap {
  min-width: 0;
}

.vocab-pick-school {
  text-align: center;
  font-size: 12px;
  font-weight: 600;
  color: var(--navy);
  margin-bottom: 8px;
}

.vocab-pick-card {
  display: block;
  width: 100%;
  margin: 0;
  padding: 0;
  border: none;
  background: transparent;
  cursor: pointer;
  perspective: 900px;
  -webkit-tap-highlight-color: transparent;
  min-height: 188px;
}

.vocab-pick-card:disabled {
  cursor: wait;
  opacity: 0.85;
}

.vocab-pick-inner {
  position: relative;
  width: 100%;
  min-height: 188px;
  transition: transform 0.55s cubic-bezier(0.4, 0.2, 0.2, 1);
  transform-style: preserve-3d;
}

.vocab-pick-card.is-flipped .vocab-pick-inner {
  transform: rotateY(180deg);
}

.vocab-pick-card.is-repick .vocab-pick-back {
  animation: vocab-pick-pulse 0.45s ease;
}

@keyframes vocab-pick-pulse {
  0%, 100% { transform: rotateY(180deg) scale(1); }
  50% { transform: rotateY(180deg) scale(1.03); }
}

.vocab-pick-face {
  position: absolute;
  inset: 0;
  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;
  border-radius: 16px;
  padding: 18px 12px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  box-sizing: border-box;
}

.vocab-pick-front {
  background: #f8fbff;
  border: 2px dashed rgba(37, 99, 235, 0.28);
  box-shadow: 0 4px 14px rgba(74, 144, 226, 0.08);
  transition: border-color 0.15s, background 0.15s;
}

.vocab-pick-card:hover .vocab-pick-front,
.vocab-pick-card:focus-visible .vocab-pick-front {
  background: #eef4ff;
  border-color: rgba(37, 99, 235, 0.45);
}

.vocab-pick-card:focus-visible {
  outline: 2px solid var(--blue);
  outline-offset: 3px;
  border-radius: 16px;
}

.vocab-pick-gift {
  font-size: 36px;
  line-height: 1;
  margin-bottom: 10px;
  display: block;
}

.vocab-pick-front-title {
  font-size: 13px;
  font-weight: 700;
  color: var(--navy);
  line-height: 1.4;
  margin-bottom: 6px;
}

.vocab-pick-front-sub {
  font-size: 11px;
  color: var(--gray);
  line-height: 1.45;
}

.vocab-pick-back {
  background: linear-gradient(155deg, #1a3a6b 0%, #1e4a8a 55%, #2563eb 100%);
  color: #ffffff;
  transform: rotateY(180deg);
  border: 1px solid rgba(255, 255, 255, 0.12);
  box-shadow: 0 8px 24px rgba(26, 58, 107, 0.35);
}

.vocab-pick-back-badge {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  font-size: 11px;
  font-weight: 700;
  padding: 4px 10px;
  border-radius: 20px;
  background: rgba(255, 255, 255, 0.18);
  margin-bottom: 8px;
}

.vocab-pick-back-type {
  font-size: 10px;
  font-weight: 600;
  opacity: 0.85;
  margin-bottom: 6px;
  letter-spacing: 0.02em;
}

.vocab-pick-back-en {
  font-size: clamp(18px, 4.5vw, 22px);
  font-weight: 700;
  line-height: 1.25;
  margin-bottom: 8px;
  word-break: break-word;
}

.vocab-pick-back-ko {
  font-size: 13px;
  line-height: 1.45;
  opacity: 0.92;
  word-break: keep-all;
  margin-bottom: 10px;
}

.vocab-pick-back-foot {
  font-size: 10px;
  line-height: 1.45;
  opacity: 0.78;
  margin-top: auto;
  padding-top: 6px;
}

.vocab-pick-back-empty {
  font-size: 13px;
  opacity: 0.9;
}

.landing-vocab-divider {
  display: flex;
  align-items: center;
  gap: 10px;
  margin: 4px 0 16px;
  font-size: 11px;
  color: #9ab0cc;
  text-align: center;
}

.landing-vocab-divider::before,
.landing-vocab-divider::after {
  content: '';
  flex: 1;
  height: 1px;
  background: #ddeaf8;
}

@media (max-width: 640px) {
  .vocab-pick-grid {
    grid-template-columns: 1fr;
    gap: 16px;
  }

  .vocab-pick-card {
    min-height: 176px;
  }

  .vocab-pick-inner {
    min-height: 176px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .vocab-pick-inner {
    transition: none;
  }

  .vocab-pick-card.is-repick .vocab-pick-back {
    animation: none;
  }
}

.landing-vocab-tabs {
  display: flex;
  gap: 8px;
  justify-content: center;
  flex-wrap: wrap;
  margin-bottom: 14px;
}

.landing-vocab-tab {
  padding: 8px 14px;
  border-radius: 20px;
  border: 1px solid #ddeaf8;
  background: #f5f9ff;
  color: var(--gray);
  font-size: 13px;
  font-weight: 500;
  cursor: pointer;
  font-family: inherit;
  transition: background 0.15s, border-color 0.15s, color 0.15s;
}

.landing-vocab-tab:hover {
  border-color: var(--blue);
  color: var(--navy);
}

.landing-vocab-tab.is-active {
  background: rgba(37, 99, 235, 0.12);
  border-color: rgba(37, 99, 235, 0.35);
  color: var(--navy);
  font-weight: 600;
}

.landing-vocab-date {
  text-align: center;
  font-size: 11px;
  color: #9ab0cc;
  margin-bottom: 10px;
}

.landing-vocab-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(120px, 1fr));
  gap: 8px;
}

.landing-vocab-card {
  background: #f5f9ff;
  border: 1px solid #ddeaf8;
  border-radius: 10px;
  padding: 10px 8px;
  text-align: center;
}

.landing-vocab-card.type-idiom {
  background: #fff9f0;
  border-color: #f0e4d0;
}

.landing-vocab-badge {
  display: inline-block;
  font-size: 10px;
  font-weight: 600;
  padding: 2px 7px;
  border-radius: 8px;
  margin-bottom: 5px;
  background: rgba(37, 99, 235, 0.12);
  color: var(--blue);
}

.landing-vocab-card.type-idiom .landing-vocab-badge {
  background: rgba(217, 119, 6, 0.12);
  color: #b45309;
}

.landing-vocab-en {
  font-size: 14px;
  font-weight: 600;
  color: var(--navy);
  word-break: break-word;
}

.landing-vocab-ko {
  font-size: 11px;
  color: var(--gray);
  margin-top: 3px;
  word-break: keep-all;
}

.landing-vocab-empty,
.landing-vocab-loading {
  text-align: center;
  padding: 20px 12px;
  font-size: 13px;
  color: var(--gray);
  background: #f5f9ff;
  border: 1px dashed #ddeaf8;
  border-radius: 12px;
}

/* ── 하단 CTA ── */
.landing-cta {
  text-align: center;
  padding: 28px 16px 12px;
}

.landing-cta-text {
  font-size: 15px;
  color: #4a6a94;
  margin-bottom: 18px;
  line-height: 1.6;
}

.landing-cta-btn {
  display: inline-block;
  width: 100%;
  max-width: 320px;
  padding: 16px 28px;
  background: linear-gradient(135deg, #2563eb 0%, #1a3a6b 100%);
  color: #fff;
  font-size: 16px;
  font-weight: 600;
  text-decoration: none;
  border-radius: 14px;
  box-shadow: 0 6px 20px rgba(37, 99, 235, 0.35);
  transition: transform 0.2s, box-shadow 0.2s;
  font-family: inherit;
}

.landing-cta-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 10px 28px rgba(37, 99, 235, 0.4);
}

.landing-footer {
  text-align: center;
  padding: 28px 12px 8px;
  font-size: 12px;
  color: #9ab0cc;
  letter-spacing: 0.5px;
}

/* ── 기능 상세 페이지 (features/*) ── */
.feature-back {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  min-width: 44px;
  min-height: 44px;
  margin: 8px 0 20px;
  border-radius: 50%;
  border: 1px solid #ddeaf8;
  background: #ffffff;
  color: var(--navy);
  text-decoration: none;
  transition: background 0.15s, border-color 0.15s, color 0.15s;
  -webkit-tap-highlight-color: transparent;
}

.feature-back:hover,
.feature-back:active {
  background: rgba(37, 99, 235, 0.1);
  border-color: rgba(37, 99, 235, 0.35);
  color: var(--blue);
}

.feature-back-icon {
  width: 20px;
  height: 20px;
  display: block;
  flex-shrink: 0;
}

.landing-detail {
  background: #ffffff;
  border: 1px solid #ddeaf8;
  border-radius: 20px;
  padding: 28px 22px;
  margin-bottom: 24px;
  box-shadow: 0 4px 20px rgba(74, 144, 226, 0.08);
}

.landing-detail-header {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 16px;
}

.landing-detail-icon {
  font-size: 32px;
  line-height: 1;
}

.landing-detail-title {
  font-family: 'Noto Serif KR', serif;
  font-size: 20px;
  font-weight: 700;
  color: var(--navy);
  line-height: 1.35;
}

.landing-detail-body p {
  font-size: 14px;
  color: #4a6a94;
  line-height: 1.75;
  margin-bottom: 12px;
}

.landing-detail-body p:last-child {
  margin-bottom: 0;
}

.landing-detail-body h3 {
  font-family: 'Noto Serif KR', serif;
  font-size: 16px;
  color: var(--navy);
  margin: 20px 0 10px;
}

.landing-detail-list {
  margin: 12px 0 14px;
  padding-left: 0;
  list-style: none;
}

.landing-detail-list li {
  position: relative;
  padding: 8px 0 8px 20px;
  font-size: 14px;
  color: #4a6a94;
  line-height: 1.65;
  border-bottom: 1px solid #f0f7ff;
}

.landing-detail-list li:last-child {
  border-bottom: none;
}

.landing-detail-list li::before {
  content: '•';
  position: absolute;
  left: 4px;
  color: var(--blue);
  font-weight: 700;
}

.landing-detail-list strong {
  color: var(--navy);
  font-weight: 600;
}

.landing-pipeline {
  display: grid;
  gap: 12px;
  margin: 16px 0;
}

.landing-pipeline-step {
  background: #f5f9ff;
  border: 1px solid #ddeaf8;
  border-radius: 12px;
  padding: 14px 16px;
}

.landing-pipeline-step strong {
  display: block;
  color: var(--navy);
  font-size: 14px;
  margin-bottom: 6px;
}

.landing-pipeline-step span {
  font-size: 13px;
  color: #4a6a94;
  line-height: 1.6;
}

@media (max-width: 520px) {
  .landing-features-grid {
    grid-template-columns: 1fr;
  }

  .landing-vocab-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .landing-detail {
    padding: 22px 16px;
  }

  .landing-nav-title {
    font-size: 13px;
    letter-spacing: 1px;
  }
}