@import url('https://fonts.googleapis.com/css2?family=Noto+Serif+KR:wght@400;600;700&family=Noto+Sans+KR:wght@300;400;500&display=swap');

:root {
  --gold: #b8935a;
  --deep-red: #7a2e2e;
  --ink: #2b2320;
  --cream: #faf6ef;
  --cream-dim: #f1e9db;
}

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

html { scroll-behavior: smooth; }

body {
  font-family: 'Noto Sans KR', sans-serif;
  background: var(--cream);
  color: var(--ink);
  overflow-x: hidden;
}

body.envelope-locked { overflow: hidden; height: 100vh; }

/* ambient particle field */
.particle-field {
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 5;
  overflow: hidden;
}

.particle {
  position: absolute;
  top: -20px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(184,147,90,0.9) 0%, rgba(184,147,90,0) 70%);
  animation: particleFall linear infinite;
}

@keyframes particleFall {
  0%   { transform: translateY(0) translateX(0) rotate(0deg); opacity: 0; }
  8%   { opacity: 0.8; }
  92%  { opacity: 0.6; }
  100% { transform: translateY(110vh) translateX(var(--drift, 40px)) rotate(180deg); opacity: 0; }
}

/* ENVELOPE INTRO */
.envelope-overlay {
  position: fixed;
  inset: 0;
  z-index: 200;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 1.75rem;
  background: radial-gradient(ellipse at center, var(--cream-dim) 0%, var(--cream) 75%);
  transition: opacity 0.8s ease, visibility 0.8s ease;
}

.envelope-overlay.opened {
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
}

.envelope {
  position: relative;
  width: min(320px, 78vw);
  height: 210px;
  perspective: 1000px;
}

.envelope-body {
  position: absolute;
  inset: 0;
  background: linear-gradient(180deg, #fffdf9, var(--cream-dim));
  border: 1px solid rgba(184, 147, 90, 0.5);
  box-shadow: 0 25px 60px -20px rgba(43, 35, 32, 0.35);
  display: flex;
  align-items: flex-end;
  justify-content: center;
  padding-bottom: 1.2rem;
}

.envelope-to {
  font-size: 0.75rem;
  letter-spacing: 0.05em;
  color: var(--ink);
  opacity: 0.7;
}

.envelope-seal {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -30%);
  width: 46px;
  height: 46px;
  border-radius: 50%;
  background: var(--deep-red);
  color: var(--cream);
  font-family: 'Noto Serif KR', serif;
  font-size: 1.3rem;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 6px 16px rgba(122,46,46,0.4);
}

.envelope-flap {
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 110px;
  background: linear-gradient(135deg, var(--cream-dim), #fffdf9);
  clip-path: polygon(0 0, 100% 0, 50% 90%);
  border: 1px solid rgba(184, 147, 90, 0.5);
  transform-origin: top center;
  transition: transform 0.9s cubic-bezier(0.5, 0, 0.2, 1);
  z-index: 2;
}

.envelope.open .envelope-flap {
  transform: rotateX(180deg);
}

.envelope-letter-peek {
  position: absolute;
  left: 8%;
  right: 8%;
  bottom: 6px;
  height: 0;
  background: #fff;
  border: 1px solid rgba(184, 147, 90, 0.35);
  box-shadow: 0 -6px 16px rgba(0,0,0,0.06);
  transition: height 0.9s cubic-bezier(0.22, 1, 0.36, 1) 0.35s, bottom 0.9s cubic-bezier(0.22, 1, 0.36, 1) 0.35s;
}

.envelope.open .envelope-letter-peek {
  height: 170px;
  bottom: 60px;
}

.envelope-open-btn {
  background: var(--deep-red);
  color: var(--cream);
  border: none;
  padding: 0.85rem 2.2rem;
  border-radius: 999px;
  font-size: 0.9rem;
  letter-spacing: 0.08em;
  cursor: pointer;
  box-shadow: 0 10px 25px -8px rgba(122,46,46,0.5);
  transition: transform 0.25s ease;
}
.envelope-open-btn:hover { transform: translateY(-2px) scale(1.03); }
.envelope-open-btn.hidden { opacity: 0; pointer-events: none; }

.envelope-hint {
  font-size: 0.75rem;
  color: var(--gold);
  letter-spacing: 0.05em;
  opacity: 0.85;
}

/* progress bar */
.progress-bar {
  position: fixed;
  top: 0; left: 0;
  height: 3px;
  width: 0%;
  background: linear-gradient(90deg, var(--gold), var(--deep-red));
  z-index: 100;
  transition: width 0.1s linear;
}

/* HERO */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 2rem;
  background: radial-gradient(ellipse at center, var(--cream-dim) 0%, var(--cream) 70%);
}

.hero-content { max-width: 700px; position: relative; z-index: 2; }

.hero-parallax {
  position: absolute;
  inset: 0;
  z-index: 1;
  overflow: hidden;
  pointer-events: none;
}

.hero-orb {
  position: absolute;
  border-radius: 50%;
  filter: blur(2px);
  opacity: 0.35;
  transition: transform 0.2s ease-out;
}
.orb-1 { width: 260px; height: 260px; top: 8%; left: 8%; background: radial-gradient(circle, var(--gold), transparent 70%); }
.orb-2 { width: 180px; height: 180px; bottom: 12%; right: 10%; background: radial-gradient(circle, var(--deep-red), transparent 70%); }
.orb-3 { width: 130px; height: 130px; top: 55%; left: 78%; background: radial-gradient(circle, var(--gold), transparent 70%); }

.hero-hanja {
  font-family: 'Noto Serif KR', serif;
  font-size: 1.6rem;
  letter-spacing: 0.3em;
  color: var(--deep-red);
  opacity: 0.8;
  margin-bottom: 0.75rem;
}

.hero-eyebrow {
  letter-spacing: 0.3em;
  font-size: 0.75rem;
  color: var(--gold);
  font-weight: 500;
  margin-bottom: 1.5rem;
}

.hero-title {
  font-family: 'Noto Serif KR', serif;
  font-weight: 700;
  font-size: clamp(2rem, 6vw, 3.4rem);
  line-height: 1.35;
  color: var(--deep-red);
  margin-bottom: 1.75rem;
}

.hero-date {
  font-size: 1rem;
  letter-spacing: 0.05em;
  color: var(--ink);
  opacity: 0.75;
  margin-bottom: 2rem;
}

.hero-sub {
  font-size: 1rem;
  line-height: 1.8;
  color: var(--ink);
  opacity: 0.65;
}

.scroll-cue {
  position: absolute;
  bottom: 2.5rem;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.6rem;
  color: var(--gold);
  font-size: 0.7rem;
  letter-spacing: 0.25em;
  transition: opacity 0.4s ease;
}

.scroll-cue-line {
  width: 1px;
  height: 40px;
  background: linear-gradient(var(--gold), transparent);
  animation: scrollPulse 1.8s ease-in-out infinite;
}

@keyframes scrollPulse {
  0%   { transform: scaleY(0.4); opacity: 0.3; }
  50%  { transform: scaleY(1);   opacity: 1; }
  100% { transform: scaleY(0.4); opacity: 0.3; }
}

/* GALLERY */
.gallery {
  position: relative;
  max-width: 1100px;
  margin: 0 auto;
  padding: 4rem 1.5rem;
  display: flex;
  flex-direction: column;
  gap: 12vh;
}

.photo-item {
  position: relative;
  opacity: 0;
  transform: translateY(60px) scale(0.96);
  transition: opacity 1s cubic-bezier(0.22, 1, 0.36, 1), transform 1.1s cubic-bezier(0.22, 1, 0.36, 1);
  will-change: transform, opacity;
}

.photo-item.in-view {
  opacity: 1;
  transform: translateY(0) scale(1);
}

.photo-item:nth-child(odd) { align-self: flex-start; }
.photo-item:nth-child(even) { align-self: flex-end; }

.photo-frame {
  position: relative;
  border: 1px solid rgba(184, 147, 90, 0.35);
  padding: 10px;
  background: #fff;
  box-shadow: 0 20px 50px -20px rgba(43, 35, 32, 0.25);
  max-width: 620px;
  transform-style: preserve-3d;
  transition: transform 0.25s ease-out, box-shadow 0.25s ease-out;
  will-change: transform;
}

.photo-frame:hover {
  box-shadow: 0 30px 60px -20px rgba(43, 35, 32, 0.35);
}

.photo-frame img {
  display: block;
  width: 100%;
  height: auto;
  max-height: 70vh;
  object-fit: cover;
}

.photo-index {
  position: absolute;
  top: -14px;
  right: -14px;
  background: var(--deep-red);
  color: var(--cream);
  font-family: 'Noto Serif KR', serif;
  font-size: 0.75rem;
  width: 32px;
  height: 32px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 4px 10px rgba(0,0,0,0.2);
}

/* LETTER */
.letter {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 6rem 2rem;
  background: linear-gradient(180deg, var(--cream) 0%, var(--cream-dim) 100%);
}

.letter-content {
  max-width: 620px;
  text-align: left;
  background: #fffdf9;
  border: 1px solid rgba(184, 147, 90, 0.3);
  box-shadow: 0 30px 70px -30px rgba(43, 35, 32, 0.3);
  padding: clamp(2rem, 6vw, 4rem);
  opacity: 0;
  transform: translateY(40px);
  transition: opacity 1s ease, transform 1s ease;
}

.letter-content.in-view {
  opacity: 1;
  transform: translateY(0);
}

.letter-eyebrow {
  letter-spacing: 0.3em;
  font-size: 0.7rem;
  color: var(--gold);
  font-weight: 500;
  margin-bottom: 1.75rem;
  text-align: center;
}

.letter-content .salutation {
  font-family: 'Noto Serif KR', serif;
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--deep-red);
  margin-bottom: 1.5rem;
}

.letter-content p {
  font-size: 0.95rem;
  line-height: 2;
  color: var(--ink);
  opacity: 0.85;
  margin-bottom: 1.4rem;
}

.letter-content .valediction {
  margin-top: 2rem;
  font-size: 1rem;
  opacity: 1;
}

.letter-content .valediction strong {
  font-family: 'Noto Serif KR', serif;
  color: var(--deep-red);
  font-size: 1.1rem;
}

.letter-date {
  text-align: center;
  font-size: 0.85rem;
  opacity: 0.55;
  margin-bottom: 2rem !important;
}

.letter-content .back-top { display: block; margin: 0 auto; }

.back-top {
  background: transparent;
  border: 1px solid var(--gold);
  color: var(--gold);
  padding: 0.7rem 1.6rem;
  border-radius: 999px;
  font-size: 0.8rem;
  letter-spacing: 0.1em;
  cursor: pointer;
  transition: background 0.3s ease, color 0.3s ease;
}
.back-top:hover { background: var(--gold); color: #fff; }

/* MUSIC PLAYER */
.music-player {
  position: fixed;
  bottom: 1.5rem;
  right: 1.5rem;
  display: flex;
  align-items: center;
  gap: 0.6rem;
  z-index: 50;
}

.music-toggle {
  width: 52px;
  height: 52px;
  border-radius: 50%;
  border: none;
  background: var(--deep-red);
  color: var(--cream);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  box-shadow: 0 8px 20px rgba(122, 46, 46, 0.4);
  transition: transform 0.2s ease;
}
.music-toggle:hover { transform: scale(1.06); }
.music-toggle .icon-note { width: 20px; height: 20px; }

.music-bars {
  display: none;
  gap: 3px;
  position: absolute;
}
.music-toggle.playing .icon-note { display: none; }
.music-toggle.playing .music-bars { display: flex; align-items: flex-end; height: 16px; }
.music-bars i {
  width: 3px;
  background: var(--cream);
  animation: bar 1s ease-in-out infinite;
}
.music-bars i:nth-child(1) { height: 60%; animation-delay: 0s; }
.music-bars i:nth-child(2) { height: 100%; animation-delay: 0.2s; }
.music-bars i:nth-child(3) { height: 40%; animation-delay: 0.4s; }

@keyframes bar {
  0%, 100% { transform: scaleY(0.4); }
  50% { transform: scaleY(1); }
}

.music-label {
  font-size: 0.7rem;
  color: var(--ink);
  background: rgba(255,255,255,0.85);
  padding: 0.4rem 0.8rem;
  border-radius: 999px;
  box-shadow: 0 4px 12px rgba(0,0,0,0.08);
  opacity: 0;
  transform: translateX(6px);
  transition: opacity 0.3s ease, transform 0.3s ease;
  white-space: nowrap;
}
.music-player:hover .music-label { opacity: 1; transform: translateX(0); }

@media (max-width: 640px) {
  .photo-item:nth-child(odd),
  .photo-item:nth-child(even) { align-self: center; }
  .photo-frame { max-width: 100%; }
  .music-label { display: none; }
  .hero-orb { display: none; }
  .letter-content { padding: 1.75rem; }
}