/* ===== 디자인 토큰 ===== */
:root {
  --color-bg: #faf7f2;
  --color-text: #2a2320;
  --color-accent: #c94a4a;      /* 따뜻한 레드 */
  --color-muted: #8a7f78;
  --color-line: #e8e0d5;

  --font-sans: 'Pretendard', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-serif: 'Noto Serif KR', serif;

  --section-py: clamp(80px, 12vw, 160px);
  --max-w: 720px;
}

body {
  font-family: var(--font-sans);
  background: var(--color-bg);
  color: var(--color-text);
  overflow-x: hidden;
}

/* ===== 스크롤 애니메이션 기본 ===== */
.reveal {
  opacity: 0;
  transform: translateY(40px);
  transition: opacity 0.9s ease, transform 0.9s ease;
  transition-delay: 0.1s;
}
.reveal.is-visible {
  opacity: 1;
  transform: translateY(0);
}

/* ===== 1. 커버 섹션 ===== */
.cover {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 40px 24px;
  background: linear-gradient(180deg, #fff5ef 0%, #faf7f2 100%);
  position: relative;
}
.cover__inner {
  text-align: center;
  max-width: var(--max-w);
}
.cover__subtitle {
  font-size: 14px;
  letter-spacing: 0.3em;
  color: var(--color-accent);
  margin-bottom: 24px;
  text-transform: uppercase;
}
.cover__title {
  font-size: clamp(56px, 12vw, 120px);
  font-weight: 800;
  line-height: 1.1;
  letter-spacing: -0.02em;
  margin-bottom: 40px;
}
.cover__date {
  font-size: 20px;
  color: var(--color-muted);
  font-weight: 500;
}
.scroll-hint {
  position: absolute;
  bottom: 40px;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
  font-size: 12px;
  letter-spacing: 0.2em;
  color: var(--color-muted);
  animation: bounce 2s ease-in-out infinite;
}
.scroll-hint .arrow { font-size: 18px; }

@keyframes bounce {
  0%, 100% { transform: translateX(-50%) translateY(0); }
  50% { transform: translateX(-50%) translateY(8px); }
}

/* ===== 2. 편지 섹션 ===== */
.letter {
  padding: var(--section-py) 24px;
  display: flex;
  justify-content: center;
}
.letter__inner {
  max-width: 560px;
  text-align: center;
  padding: 60px 40px;
  border: 1px solid var(--color-line);
  border-radius: 4px;
  background: #fff;
  box-shadow: 0 1px 30px rgba(0,0,0,0.03);
}
.letter__body {
  font-size: clamp(18px, 2.2vw, 22px);
  line-height: 1.9;
  color: var(--color-text);
  font-family: var(--font-serif);
}

/* ===== 3. DAY 섹션 ===== */
.day {
  padding: var(--section-py) 24px;
  max-width: var(--max-w);
  margin: 0 auto;
}
.day__header {
  margin-bottom: 60px;
  text-align: center;
}
.day__label {
  display: inline-block;
  font-size: 12px;
  letter-spacing: 0.4em;
  color: var(--color-accent);
  margin-bottom: 16px;
  padding: 6px 16px;
  border: 1px solid var(--color-accent);
  border-radius: 999px;
}
.day__title {
  font-size: clamp(32px, 5vw, 48px);
  font-weight: 700;
  letter-spacing: -0.02em;
}

/* 타임라인 */
.timeline {
  position: relative;
  padding-left: 32px;
}
.timeline::before {
  content: '';
  position: absolute;
  left: 8px;
  top: 8px;
  bottom: 8px;
  width: 2px;
  background: var(--color-line);
}
.timeline__item {
  position: relative;
  padding: 0 0 48px 32px;
}
.timeline__item::before {
  content: '';
  position: absolute;
  left: -32px;
  top: 8px;
  width: 18px;
  height: 18px;
  background: var(--color-accent);
  border: 3px solid var(--color-bg);
  border-radius: 50%;
  box-shadow: 0 0 0 2px var(--color-accent);
}
.timeline__item time {
  display: block;
  font-size: 13px;
  font-weight: 600;
  color: var(--color-accent);
  letter-spacing: 0.1em;
  margin-bottom: 8px;
}
.timeline__item h3 {
  font-size: 22px;
  font-weight: 700;
  margin-bottom: 6px;
}
.timeline__item p {
  color: var(--color-muted);
  font-size: 15px;
}

/* ===== 4. 엔딩 ===== */
.ending {
  padding: var(--section-py) 24px;
  text-align: center;
  background: linear-gradient(180deg, var(--color-bg) 0%, #fff5ef 100%);
  min-height: 70vh;
  display: flex;
  align-items: center;
  justify-content: center;
}
.ending__inner h2 {
  font-size: clamp(36px, 6vw, 56px);
  font-weight: 700;
  margin-bottom: 20px;
  letter-spacing: -0.02em;
}
.ending__inner p {
  font-size: 18px;
  color: var(--color-muted);
  margin-bottom: 8px;
}
.ending__inner .heart {
  font-size: 48px;
  margin-top: 40px;
  animation: heartbeat 1.5s ease-in-out infinite;
}
@keyframes heartbeat {
  0%, 100% { transform: scale(1); }
  50% { transform: scale(1.15); }
}

/* ===== 반응형 ===== */
@media (max-width: 600px) {
  .letter__inner { padding: 40px 24px; }
  .timeline { padding-left: 24px; }
  .timeline__item { padding-left: 24px; }
  .timeline__item::before { left: -24px; width: 14px; height: 14px; }
}