:root {
  --bg: #fdf6f0;
  --bg2: #faeee4;
  --ink: #3a2e28;
  --ink-soft: #6b5a52;
  --paper: #fffdf8;
  --paper-line: #e8ddd0;
  --shadow: rgba(100, 60, 40, 0.16);

  --env-apology: #c5f7d9;
  --env-apology-dark: #a0e8b8;
  --env-colleague: #c5d9f7;
  --env-colleague-dark: #a0b8e8;
  --env-friend: #f7c5d0;
  --env-friend-dark: #e8a0b4;
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  -webkit-tap-highlight-color: transparent;
  user-select: none;
  -webkit-user-select: none;
  -webkit-user-drag: none;
}

img, button, .envelope, .letter-stage {
  -webkit-user-drag: none;
  user-select: none;
}

body {
  font-family: "Lora", serif;
  color: var(--ink);
  min-height: 100vh;
  overflow: hidden;
  background: var(--bg);
  background-image:
    radial-gradient(circle at 16% 22%, #fde8d8 0%, transparent 45%),
    radial-gradient(circle at 84% 80%, #dbe8ff 0%, transparent 48%),
    radial-gradient(circle at 52% 52%, #d8fde8 0%, transparent 58%);
}

body::before {
  content: "";
  position: fixed;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  opacity: 0.06;
  background-image: radial-gradient(rgba(80, 50, 30, 0.16) 0.5px, transparent 0.5px);
  background-size: 3px 3px;
}

#zoom-root {
  position: fixed;
  inset: 0;
  transform-origin: center center;
  transition: transform 0.12s ease;
}

#petals {
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 1;
}

.petal {
  position: fixed;
  pointer-events: none;
  opacity: 0.45;
  animation: float-petal linear infinite;
}

@keyframes float-petal {
  0% {
    transform: translateY(-18px) rotate(0deg);
    opacity: 0;
  }
  12% { opacity: 0.45; }
  90% { opacity: 0.3; }
  100% {
    transform: translateY(100vh) rotate(360deg);
    opacity: 0;
  }
}

.landing {
  position: fixed;
  inset: 0;
  z-index: 10;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: clamp(30px, 7vw, 68px);
  transition: opacity 0.45s ease, visibility 0.45s ease;
}

.landing.hidden {
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
}

.heading {
  text-align: center;
}

.for-text {
  font-family: "Dancing Script", cursive;
  font-size: clamp(2.4rem, 7.4vw, 5rem);
  font-weight: 700;
  color: var(--ink);
  text-shadow: 0 2px 12px rgba(70, 40, 30, 0.1);
}

.landing-footer-text {
  position: absolute;
  bottom: clamp(20px, 5vh, 40px);
  width: 90%;
  left: 50%;
  transform: translateX(-50%);
  text-align: center;
  font-size: clamp(0.9rem, 2vw, 1.2rem);
  color: var(--ink-soft);
  line-height: 1.6;
  opacity: 0.9;
}

.envelopes-row {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: clamp(16px, 3.6vw, 56px);
  align-items: flex-end;
}

.env-wrapper {
  border: 0;
  background: transparent;
  cursor: pointer;
  display: flex;
  flex-direction: column;
  gap: 12px;
  align-items: center;
  transform: translateY(0);
  transition: transform 0.24s ease;
}

.env-wrapper:hover {
  transform: translateY(-10px);
}

.env-word {
  font-family: "Playfair Display", serif;
  font-style: italic;
  color: var(--ink-soft);
  font-size: clamp(1rem, 2.3vw, 1.45rem);
}

.envelope {
  position: relative;
  width: clamp(160px, 24vw, 240px);
  height: clamp(110px, 16.5vw, 164px);
  filter: drop-shadow(0 10px 22px var(--shadow));
}

.env-body {
  position: absolute;
  inset: 0;
  border-radius: 6px 6px 11px 11px;
}

.env-front {
  position: absolute;
  inset: 0;
  overflow: hidden;
  border-radius: 6px 6px 11px 11px;
}

.env-front::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 62%;
  clip-path: polygon(0% 100%, 50% 0%, 100% 100%);
}

.env-front::before {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  top: 0;
  height: 56%;
  clip-path: polygon(0% 0%, 100% 0%, 50% 100%);
  z-index: 3;
}

.env-seal {
  position: absolute;
  top: 50%;
  left: 50%;
  width: 36px;
  height: 36px;
  border-radius: 999px;
  display: grid;
  place-items: center;
  transform: translate(-50%, -50%);
  z-index: 5;
  font-size: 16px;
  font-size: 12px;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.16);
}

.env-apology .env-body { background: var(--env-apology); }
.env-apology .env-front::after { background: var(--env-apology-dark); }
.env-apology .env-front::before { background: color-mix(in srgb, var(--env-apology) 85%, white); }
.env-apology .env-seal { background: var(--env-apology-dark); color: #fff; }

.env-colleague .env-body { background: var(--env-colleague); }
.env-colleague .env-front::after { background: var(--env-colleague-dark); }
.env-colleague .env-front::before { background: color-mix(in srgb, var(--env-colleague) 85%, white); }
.env-colleague .env-seal { background: var(--env-colleague-dark); color: #fff; }

.env-friend .env-body { background: var(--env-friend); }
.env-friend .env-front::after { background: var(--env-friend-dark); }
.env-friend .env-front::before { background: color-mix(in srgb, var(--env-friend) 85%, white); }
.env-friend .env-seal { background: var(--env-friend-dark); color: #fff; }

.viewer {
  position: fixed;
  inset: 0;
  z-index: 120;
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.35s ease, visibility 0.35s ease;
  user-select: none;
  -webkit-user-select: none;
}

.viewer.active {
  opacity: 1;
  visibility: visible;
}

.viewer-backdrop {
  position: absolute;
  inset: 0;
  background: var(--viewer-bg, rgba(253, 246, 240, 0.9));
  backdrop-filter: blur(11px);
  transition: background 0.8s ease, opacity 0.6s ease;
}

.viewer-content {
  position: relative;
  z-index: 1;
  height: 100%;
  width: min(95vw, 760px);
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 24px;
  padding: 20px;
}

.viewer-title {
  font-family: "Dancing Script", cursive;
  font-size: clamp(1.6rem, 4.3vw, 2.4rem);
  color: var(--ink);
  opacity: 0;
  transform: translateY(-10px);
  transition: opacity 0.45s ease, transform 0.45s ease;
}

.viewer-title.shown {
  opacity: 1;
  transform: translateY(0);
}

.stage-container {
  display: grid;
  place-items: center;
  width: 100%;
}

.stage-container > * {
  grid-area: 1 / 1;
}

.center-envelope {
  position: relative;
  width: clamp(250px, 38vw, 360px);
  height: clamp(171px, 26vw, 246px);
  perspective: 1200px;
  transform-style: preserve-3d;
  transform-origin: center center;
  transition: transform 0.85s cubic-bezier(0.22, 1, 0.36, 1), opacity 0.32s ease;
  z-index: 10;
}

.center-envelope.hidden {
  opacity: 0;
  pointer-events: none;
}

#env-anim-body,
#env-flap,
#env-bottom-v {
  position: absolute;
}

#env-anim-body {
  inset: 0;
  border-radius: 6px 6px 12px 12px;
  box-shadow: 0 16px 44px var(--shadow);
}

#env-flap {
  left: 0;
  right: 0;
  top: 0;
  height: 56%;
  clip-path: polygon(0% 0%, 100% 0%, 50% 100%);
  transform-origin: top center;
  transition: transform 0.68s cubic-bezier(0.4, 0, 0.2, 1);
  z-index: 4;
}

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

#env-bottom-v {
  left: 0;
  right: 0;
  bottom: 0;
  height: 62%;
  clip-path: polygon(0% 100%, 50% 0%, 100% 100%);
  z-index: 2;
}

.env-seal-center {
  position: absolute;
  top: 50%;
  left: 50%;
  width: 48px;
  height: 48px;
  border-radius: 999px;
  display: grid;
  place-items: center;
  transform: translate(-50%, -50%);
  z-index: 8;
  font-size: 20px;
  font-size: 15px;
  box-shadow: 0 3px 10px rgba(0, 0, 0, 0.18);
  transition: opacity 0.25s ease;
}

.env-seal-center.hidden {
  opacity: 0;
}

.letter-stage {
  position: relative;
  /* Auto-scale A4 based on BOTH max width and max height of the screen */
  --max-w: 90vw;
  --max-h: 75vh;
  --w-by-h: calc(var(--max-h) / 1.4142);
  width: min(var(--max-w), var(--w-by-h), 560px);
  height: calc(min(var(--max-w), var(--w-by-h), 560px) * 1.4142);
  display: none;
  align-items: flex-start;
  justify-content: center;
  perspective: 1600px;
  transform-origin: center center;
  transition: transform 0.85s cubic-bezier(0.22, 1, 0.36, 1), opacity 0.85s cubic-bezier(0.22, 1, 0.36, 1);
  z-index: 20;
  user-select: none;
  -webkit-user-select: none;
  cursor: grab;
}

.letter-stage.morphing {
  display: block;
}

.letter-page {
  width: 100%;
  height: 100%;
  position: absolute;
  top: 0;
  left: 0;
  transform-style: preserve-3d;
  perspective: 2000px; /* Strong perspective for 3D realism */
}

.paper-3d-wrapper {
  width: 100%;
  height: 100%;
  position: absolute;
  top: 0;
  right: 0;
  transform-style: preserve-3d;
}

.paper-3d-container {
  width: 100%;
  height: 100%;
  position: relative;
  transform-style: preserve-3d;
}

.state-open .paper-3d-container {
  box-shadow: 0 14px 40px rgba(100, 60, 40, 0.2);
}

.paper-half {
  width: 100%;
  height: 50%;
  position: absolute;
  left: 0;
  transform-style: preserve-3d;
}

.top-half { top: 0; z-index: 2; }
.bottom-half {
  top: 50%;
  transform-origin: top center;
  z-index: 3;
}

.paper-quad {
  width: 50%;
  height: 100%;
  position: absolute;
  top: 0;
  transform-style: preserve-3d;
}

.quad-front {
  position: absolute;
  inset: 0;
  overflow: hidden;
  background: var(--paper);
  box-shadow: inset 0 0 0 1px rgba(200, 180, 160, 0.25);
  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;
  transform-style: preserve-3d;
}

.quad-back {
  position: absolute;
  inset: 0;
  background: #fdf5ea;
  box-shadow: inset 0 0 0 1px rgba(200, 180, 160, 0.15);
  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;
  transform: rotateY(180deg) translateZ(0.5px);
  overflow: hidden;
  transform-style: preserve-3d;
}

/* Inner fold shadows */
.quad-front::after {
  content: "";
  position: absolute;
  inset: -50px;
  background: linear-gradient(90deg, rgba(80, 50, 30, 0.1) 0%, transparent 20%, transparent 80%, rgba(80, 50, 30, 0.1) 100%);
  pointer-events: none;
  z-index: 5;
  opacity: 0;
  transition: opacity 0.8s ease;
}

.top-left, .bottom-left { left: 0; z-index: 1; }
.top-right, .bottom-right {
  left: 50%;
  transform-origin: left center;
  z-index: 2;
}

.quad-inner {
  width: 200%;
  height: 200%;
  position: absolute;
  transform-style: preserve-3d;
}

.tl-inner { top: 0; left: 0; }
.tr-inner { top: 0; left: -100%; }
.bl-inner { top: -100%; left: 0; }
.br-inner { top: -100%; left: -100%; }

/* The actual content overlay that spans perfectly */
.quad-content-layer {
  width: 100%;
  height: 100%;
  position: absolute;
  top: 0; left: 0;
  display: flex;
  flex-direction: column;
  background: transparent;
  transform: translateZ(0.5px);
  -webkit-backface-visibility: hidden;
  backface-visibility: hidden;
}

/* 3D Fold State Classes */
.state-folded .paper-3d-wrapper { transform: translate(25%, 25%); }
.state-folded .bottom-half { transform: rotateX(179.9deg) translateZ(-2.1px); }
.state-folded .top-right { transform: rotateY(179.9deg) translateZ(-1px); }
.state-folded .bottom-right { transform: rotateY(-179.9deg) translateZ(-1px); }
.state-folded .quad-front::after { opacity: 0.8; }

/* Unfold Timeline */
.unfold-step1 .paper-3d-wrapper {
  transform: translate(0, 25%);
  transition: transform 0.9s cubic-bezier(0.4, 0, 0.2, 1);
}
.unfold-step1 .bottom-half { transform: rotateX(179.9deg) translateZ(-2.1px); }
.unfold-step1 .top-right {
  animation: unfold-horiz 0.9s cubic-bezier(0.4, 0, 0.2, 1) forwards;
}
.unfold-step1 .bottom-right {
  animation: unfold-horiz-inv 0.9s cubic-bezier(0.4, 0, 0.2, 1) forwards;
}
.unfold-step1 .quad-front::after { opacity: 0.4; }

.unfold-step2 .paper-3d-wrapper {
  transform: translate(0, 0);
  transition: transform 0.9s cubic-bezier(0.4, 0, 0.2, 1);
}
.unfold-step2 .top-right, .unfold-step2 .bottom-right { transform: rotateY(0deg); }
.unfold-step2 .bottom-half {
  animation: unfold-vert 0.9s cubic-bezier(0.4, 0, 0.2, 1) forwards;
}

/* Fully Open */
.state-open .paper-3d-wrapper { transform: translate(0, 0); }
.state-open .top-right, .state-open .bottom-right { transform: rotateY(0deg); }
.state-open .bottom-half { transform: rotateX(0deg); }

/* Fold Reverse Timeline (For Pagination/Close) */
.fold-step1 .paper-3d-wrapper {
  transform: translate(0, 25%);
  transition: transform 0.8s cubic-bezier(0.4, 0, 0.2, 1);
}
.fold-step1 .top-right, .fold-step1 .bottom-right { transform: rotateY(0deg); }
.fold-step1 .bottom-half {
  animation: fold-vert 0.8s cubic-bezier(0.4, 0, 0.2, 1) forwards;
}
.fold-step1 .quad-front::after { opacity: 0.4; }

.fold-step2 .paper-3d-wrapper {
  transform: translate(25%, 25%);
  transition: transform 0.8s cubic-bezier(0.4, 0, 0.2, 1);
}
.fold-step2 .bottom-half { transform: rotateX(179.9deg) translateZ(-2.1px); }
.fold-step2 .top-right {
  animation: fold-horiz 0.8s cubic-bezier(0.4, 0, 0.2, 1) forwards;
}
.fold-step2 .bottom-right {
  animation: fold-horiz-inv 0.8s cubic-bezier(0.4, 0, 0.2, 1) forwards;
}
.fold-step2 .quad-front::after { opacity: 0.8; }

@keyframes unfold-horiz {
  0% { transform: rotateY(179.9deg) translateZ(-1px); }
  100% { transform: rotateY(0deg) translateZ(0px); }
}
@keyframes unfold-horiz-inv {
  0% { transform: rotateY(-179.9deg) translateZ(-1px); }
  100% { transform: rotateY(0deg) translateZ(0px); }
}
@keyframes unfold-vert {
  0% { transform: rotateX(179.9deg) translateZ(-2.1px); }
  100% { transform: rotateX(0deg) translateZ(0px); }
}
@keyframes fold-vert {
  0% { transform: rotateX(0deg) translateZ(0px); }
  100% { transform: rotateX(179.9deg) translateZ(-2.1px); }
}
@keyframes fold-horiz {
  0% { transform: rotateY(0deg) translateZ(0px); }
  100% { transform: rotateY(179.9deg) translateZ(-1px); }
}
@keyframes fold-horiz-inv {
  0% { transform: rotateY(0deg) translateZ(0px); }
  100% { transform: rotateY(-179.9deg) translateZ(-1px); }
}

.letter-body {
  white-space: pre-line;
  display: block;
}


.letter-image-wrap {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  margin: 0;
  padding: 0;
  border: none;
  border-radius: 0;
  box-shadow: none;
  background: transparent;
  z-index: 1;
}

.letter-image {
  width: 100%;
  height: 100%;
  display: block;
  object-fit: cover; /* Back to cover so it bleeds fully across the mapped areas without letterbox white bars */
}


.placeholder-text {
  font-style: italic;
  color: #b0948a;
}

.page-indicator {
  min-height: 18px;
  text-align: center;
  color: var(--ink-soft);
  letter-spacing: 0.12em;
  text-transform: uppercase;
  font-size: 0.75rem;
  opacity: 0.8;
}

.nav-row {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 16px;
}

.nav-btn {
  display: none;
  border: 1.5px solid var(--paper-line);
  border-radius: 999px;
  background: #ffffff;
  color: var(--ink);
  font-family: "Lora", serif;
  font-size: 0.84rem;
  padding: 10px 26px;
  cursor: pointer;
  transition: all 0.22s ease;
  box-shadow: 0 3px 12px var(--shadow);
}

.nav-btn:hover {
  background: var(--ink);
  color: #ffffff;
  transform: translateY(-2px);
  border-color: var(--ink);
}

.nav-btn.visible {
  display: inline-block;
}

.close-btn {
  position: fixed;
  top: 24px;
  right: 28px;
  z-index: 200;
  width: 44px;
  height: 44px;
  border: 1.5px solid var(--paper-line);
  border-radius: 50%;
  background: #fff;
  color: var(--ink);
  display: grid;
  place-items: center;
  font-size: 1.12rem;
  cursor: pointer;
  box-shadow: 0 4px 14px var(--shadow);
  transition: all 0.24s ease;
  opacity: 0;
  visibility: hidden;
}

.close-btn.visible {
  opacity: 1;
  visibility: visible;
}

.close-btn:hover {
  background: var(--ink);
  color: #fff;
  transform: rotate(90deg);
}

@media (max-width: 620px) {
  .viewer-content {
    gap: 18px;
    padding-top: 50px;
  }

  .envelopes-row {
    gap: 14px;
  }

  .envelope {
    width: 140px;
    height: 96px;
  }

  .env-seal {
    width: 28px;
    height: 28px;
    font-size: 14px;
  }

  .close-btn {
    top: 14px;
    right: 14px;
  }
}

/* Toast Notification */
.toast {
  position: fixed;
  bottom: 24px;
  left: 50%;
  transform: translateX(-50%) translateY(20px);
  background: var(--ink);
  color: #fff;
  padding: 12px 24px;
  border-radius: 8px;
  font-family: "Poppins", sans-serif;
  font-size: 0.95rem;
  opacity: 0;
  visibility: hidden;
  transition: all 0.3s ease;
  z-index: 1000;
  box-shadow: 0 4px 12px var(--shadow);
  text-align: center;
  max-width: 90%;
  pointer-events: none;
}
.toast.show {
  opacity: 1;
  visibility: visible;
  transform: translateX(-50%) translateY(0);
}

/* Page Flip Transitions */
.flip-out-next .paper-3d-wrapper {
  transform: rotateY(-90deg) scale(0.9);
  transition: transform 0.4s cubic-bezier(0.4, 0, 1, 1);
}
.flip-in-next .paper-3d-wrapper {
  transform: rotateY(90deg) scale(0.9);
  animation: flip-in-anim 0.4s cubic-bezier(0, 0, 0.2, 1) forwards;
}
.flip-out-prev .paper-3d-wrapper {
  transform: rotateY(90deg) scale(0.9);
  transition: transform 0.4s cubic-bezier(0.4, 0, 1, 1);
}
.flip-in-prev .paper-3d-wrapper {
  transform: rotateY(-90deg) scale(0.9);
  animation: flip-in-anim-prev 0.4s cubic-bezier(0, 0, 0.2, 1) forwards;
}

@keyframes flip-in-anim {
  100% { transform: rotateY(0deg) scale(1); }
}
@keyframes flip-in-anim-prev {
  100% { transform: rotateY(0deg) scale(1); }
}

.flip-out-next .top-right, .flip-out-next .bottom-right,
.flip-in-next .top-right, .flip-in-next .bottom-right,
.flip-out-prev .top-right, .flip-out-prev .bottom-right,
.flip-in-prev .top-right, .flip-in-prev .bottom-right {
}

.flip-out-next .bottom-half, .flip-in-next .bottom-half,
.flip-out-prev .bottom-half, .flip-in-prev .bottom-half {
}


/* Page Flip Transitions */
.flip-out-next .paper-3d-wrapper {
  transform: rotateY(-90deg) scale(0.9) translate3d(0,0,0);
  transition: transform 0.4s cubic-bezier(0.4, 0, 1, 1), opacity 0.4s;
  opacity: 0;
}
.flip-in-next .paper-3d-wrapper {
  transform: rotateY(90deg) scale(0.9) translate3d(0,0,0);
  animation: flip-in-anim 0.4s cubic-bezier(0, 0, 0.2, 1) forwards;
  opacity: 0;
}

.flip-out-prev .paper-3d-wrapper {
  transform: rotateY(90deg) scale(0.9) translate3d(0,0,0);
  transition: transform 0.4s cubic-bezier(0.4, 0, 1, 1), opacity 0.4s;
  opacity: 0;
}
.flip-in-prev .paper-3d-wrapper {
  transform: rotateY(-90deg) scale(0.9) translate3d(0,0,0);
  animation: flip-in-anim-prev 0.4s cubic-bezier(0, 0, 0.2, 1) forwards;
  opacity: 0;
}

@keyframes flip-in-anim {
  100% { transform: rotateY(0deg) scale(1) translate3d(0,0,0); opacity: 1; }
}
@keyframes flip-in-anim-prev {
  100% { transform: rotateY(0deg) scale(1) translate3d(0,0,0); opacity: 1; }
}

.flip-out-next .top-right, .flip-out-next .bottom-right,
.flip-in-next .top-right, .flip-in-next .bottom-right,
.flip-out-prev .top-right, .flip-out-prev .bottom-right,
.flip-in-prev .top-right, .flip-in-prev .bottom-right {
  transform: rotateY(0deg) !important;
  animation: none !important;
}

.flip-out-next .bottom-half, .flip-in-next .bottom-half,
.flip-out-prev .bottom-half, .flip-in-prev .bottom-half {
  transform: rotateX(0deg) !important;
  animation: none !important;
}