/* ===== Reset & Variables ===== */
*,
*::before,
*::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

:root {
  /* Colors */
  --color-cream: #fdf6f0;
  --color-cream-dark: #f5ebe0;
  --color-rose: #e8a0b4;
  --color-rose-dark: #d47a92;
  --color-rose-light: #f5d6d0;
  --color-gold: #d4a574;
  --color-gold-light: #e8c9a8;
  --color-text: #3d2327;
  --color-text-light: #7a555c;
  --color-white: #ffffff;
  --color-shadow: rgba(61, 35, 39, 0.08);
  --color-shadow-strong: rgba(61, 35, 39, 0.15);

  /* Typography */
  --font-serif: 'Noto Serif SC', 'Georgia', 'Times New Roman', serif;
  --font-script: 'Dancing Script', cursive;

  /* Spacing */
  --section-padding: 3rem 1.5rem;
  --card-radius: 1.25rem;

  /* Transitions */
  --transition-smooth: cubic-bezier(0.4, 0, 0.2, 1);
}

/* ===== Base ===== */
html {
  scroll-behavior: smooth;
  -webkit-tap-highlight-color: transparent;
}

body {
  font-family: var(--font-serif);
  color: var(--color-text);
  background: var(--color-cream);
  line-height: 1.8;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

/* ===== Section Titles ===== */
.section-title {
  font-size: 1.75rem;
  font-weight: 700;
  text-align: center;
  letter-spacing: 0.15em;
  color: var(--color-rose-dark);
  margin-bottom: 2rem;
  position: relative;
}

.section-title::after {
  content: '';
  display: block;
  width: 3rem;
  height: 2px;
  background: linear-gradient(90deg, transparent, var(--color-gold), transparent);
  margin: 0.75rem auto 0;
}

/* ===== Reveal Animation (scroll-triggered) ===== */
.reveal {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.8s var(--transition-smooth),
              transform 0.8s var(--transition-smooth);
  will-change: opacity, transform;
}

.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ===== Mobile Performance: Content Visibility ===== */
[data-content-visibility] {
  content-visibility: auto;
  contain-intrinsic-size: auto 600px;
}

/* ===== Hero ===== */
#hero {
  position: relative;
  min-height: 100vh;
  min-height: 100dvh;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
  contain: layout style paint;
  background: linear-gradient(
    170deg,
    var(--color-cream) 0%,
    var(--color-rose-light) 35%,
    var(--color-rose) 70%,
    var(--color-rose-dark) 100%
  );
  background-size: 200% 200%;
  animation: gradientShift 12s ease infinite;
  will-change: background-position;
}

@keyframes gradientShift {
  0%   { background-position: 0% 50%; }
  50%  { background-position: 100% 50%; }
  100% { background-position: 0% 50%; }
}

.hero-bg-ornament {
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse 80% 50% at 50% 100%, rgba(255,255,255,0.3) 0%, transparent 70%),
    radial-gradient(ellipse 40% 60% at 20% 10%, rgba(255,255,255,0.15) 0%, transparent 60%),
    radial-gradient(ellipse 30% 40% at 80% 20%, rgba(212,165,116,0.15) 0%, transparent 50%);
  pointer-events: none;
}

.hero-content {
  position: relative;
  z-index: 2;
  text-align: center;
  padding: 2rem;
  animation: heroFadeIn 1.2s var(--transition-smooth) forwards;
  will-change: opacity, transform;
}

@keyframes heroFadeIn {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.hero-sub-en {
  font-family: var(--font-script);
  font-size: 1.2rem;
  color: var(--color-gold);
  letter-spacing: 0.1em;
  margin-bottom: 0.5rem;
  opacity: 0.8;
}

.hero-title {
  font-size: clamp(2.5rem, 8vw, 4rem);
  font-weight: 900;
  color: var(--color-text);
  letter-spacing: 0.1em;
  line-height: 1.3;
  text-shadow: 0 2px 20px rgba(212, 165, 116, 0.2);
  margin-bottom: 1rem;
  user-select: none;
  -webkit-user-select: none;
  cursor: default;
}

.hero-sub-zh {
  font-size: 0.95rem;
  color: var(--color-text-light);
  letter-spacing: 0.3em;
  opacity: 0.8;
}

/* ===== Scroll Hint ===== */
.scroll-hint {
  position: absolute;
  bottom: -4rem;
  left: 50%;
  transform: translateX(-50%);
  background: none;
  border: none;
  cursor: pointer;
  padding: 0.5rem;
  animation: scrollBounce 2s ease-in-out infinite;
}

.scroll-arrow {
  display: block;
  width: 1.5rem;
  height: 1.5rem;
  border-right: 2px solid var(--color-gold);
  border-bottom: 2px solid var(--color-gold);
  transform: rotate(45deg);
  opacity: 0.6;
}

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

/* ===== Petals ===== */
.petals-layer {
  position: absolute;
  inset: 0;
  z-index: 1;
  pointer-events: none;
  overflow: hidden;
  contain: strict;
}

.petal {
  position: absolute;
  top: -3rem;
  width: 1.2rem;
  height: 0.7rem;
  border-radius: 50% 50% 50% 0;
  background: var(--color-rose-light);
  opacity: 0;
  will-change: transform, opacity;
  transform: translateZ(0);
}

/* ===== Letter Section ===== */
#letter {
  padding: var(--section-padding);
  background:
    linear-gradient(180deg, var(--color-cream) 0%, var(--color-cream-dark) 100%);
  display: flex;
  justify-content: center;
  contain: layout style paint;
}

.letter-card {
  max-width: 36rem;
  width: 100%;
  background: var(--color-white);
  border-radius: var(--card-radius);
  padding: 2.5rem 1.75rem;
  position: relative;
  box-shadow:
    0 4px 24px var(--color-shadow),
    0 1px 4px var(--color-shadow);
  border: 1px solid rgba(212, 165, 116, 0.15);
  overflow: hidden;
  transition: box-shadow 0.4s var(--transition-smooth);
}

.letter-deco {
  position: absolute;
  top: 1rem;
  left: 1rem;
  right: 1rem;
  height: 4px;
  background: linear-gradient(
    90deg,
    transparent,
    var(--color-rose-light),
    var(--color-gold-light),
    var(--color-rose-light),
    transparent
  );
  border-radius: 2px;
  opacity: 0.6;
}

.letter-body {
  margin-top: 0.5rem;
}

.letter-body p {
  font-size: 0.95rem;
  line-height: 2;
  color: var(--color-text);
  margin-bottom: 1.2rem;
  text-indent: 2em;
}

.letter-body p:first-child {
  text-indent: 0;
}

.letter-highlight {
  text-indent: 0 !important;
  font-weight: 600;
  font-size: 1.05rem !important;
  color: var(--color-rose-dark) !important;
  text-align: center;
  padding: 1rem 0;
  line-height: 2.2 !important;
}

.letter-sign {
  text-indent: 0 !important;
  text-align: right;
  color: var(--color-text-light) !important;
  font-style: italic;
  margin-top: 0.5rem;
}

/* ===== Gallery Section ===== */
#gallery {
  padding: var(--section-padding);
  background: var(--color-cream);
  contain: layout style paint;
}

.gallery-grid {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
  max-width: 36rem;
  margin: 0 auto;
}

.memory-card {
  background: var(--color-white);
  border-radius: var(--card-radius);
  overflow: hidden;
  box-shadow: 0 4px 20px var(--color-shadow);
  border: 1px solid rgba(212, 165, 116, 0.1);
  transition: transform 0.4s var(--transition-smooth),
              box-shadow 0.4s var(--transition-smooth);
  position: relative;
}

.memory-card:hover,
.memory-card:focus-within {
  transform: translateY(-4px);
  box-shadow: 0 8px 32px var(--color-shadow-strong);
}

.card-illustration {
  height: 10rem;
  display: flex;
  align-items: center;
  justify-content: center;
  background: linear-gradient(
    135deg,
    var(--color-rose-light) 0%,
    var(--color-cream-dark) 100%
  );
  color: var(--color-rose-dark);
}

.card-svg {
  width: 5rem;
  height: 5rem;
}

.card-body {
  padding: 1.25rem 1.5rem 1.5rem;
}

.card-title {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: 0.5rem;
  letter-spacing: 0.05em;
}

.card-text {
  font-size: 0.88rem;
  line-height: 1.8;
  color: var(--color-text-light);
}

/* ===== Gratitude Section ===== */
#gratitude {
  padding: var(--section-padding);
  text-align: center;
  position: relative;
  overflow: hidden;
  contain: layout style paint;
  background: linear-gradient(
    180deg,
    var(--color-cream-dark) 0%,
    var(--color-rose-light) 50%,
    var(--color-cream) 100%
  );
}

.gratitude-bg-flowers {
  position: absolute;
  inset: 0;
  pointer-events: none;
  opacity: 0.06;
  background:
    radial-gradient(circle at 20% 30%, var(--color-rose) 0%, transparent 30%),
    radial-gradient(circle at 80% 60%, var(--color-gold) 0%, transparent 35%),
    radial-gradient(circle at 50% 20%, var(--color-rose-dark) 0%, transparent 25%);
  background-size: 100% 100%;
}

.gratitude-content {
  position: relative;
  z-index: 1;
}

.gratitude-text {
  font-size: 1rem;
  line-height: 2.2;
  color: var(--color-text);
  margin-bottom: 2rem;
}

/* ===== Heart Interact ===== */
.heart-interact {
  display: inline-flex;
  flex-direction: column;
  align-items: center;
  gap: 0.75rem;
  cursor: pointer;
  border: none;
  background: none;
  padding: 0.5rem;
  -webkit-tap-highlight-color: transparent;
  outline: none;
  position: relative;
}

.heart-interact:focus-visible {
  outline: 2px solid var(--color-rose-dark);
  outline-offset: 4px;
  border-radius: 8px;
}

.heart-icon {
  color: var(--color-rose);
  transition: transform 0.3s var(--transition-smooth),
              color 0.3s var(--transition-smooth);
  will-change: transform;
}

.heart-interact:hover .heart-icon,
.heart-interact:active .heart-icon {
  transform: scale(1.15);
  color: var(--color-rose-dark);
}

.heart-icon svg {
  display: block;
  width: 4rem;
  height: 4rem;
  filter: drop-shadow(0 2px 8px rgba(212, 165, 116, 0.3));
}

.heart-hint {
  font-size: 0.8rem;
  color: var(--color-text-light);
  letter-spacing: 0.1em;
  opacity: 0.7;
  transition: opacity 0.3s;
}

.heart-interact:hover .heart-hint,
.heart-interact:active .heart-hint {
  opacity: 1;
}

/* Heart click counter */
.heart-counter {
  position: absolute;
  top: -0.5rem;
  right: -1.5rem;
  font-size: 0.7rem;
  color: var(--color-rose);
  background: var(--color-white);
  border-radius: 50%;
  width: 1.6rem;
  height: 1.6rem;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  box-shadow: 0 2px 8px var(--color-shadow);
  opacity: 0;
  transform: scale(0);
  transition: opacity 0.3s, transform 0.3s;
}

.heart-counter.show {
  opacity: 1;
  transform: scale(1);
}

/* ===== Flying Hearts (WAAPI driven) ===== */
.hearts-container {
  position: fixed;
  inset: 0;
  z-index: 1000;
  pointer-events: none;
  overflow: hidden;
}

.flying-heart {
  position: absolute;
  color: var(--color-rose);
  will-change: transform, opacity;
  transform: translateZ(0);
  pointer-events: none;
}

/* ===== Eggs Layer (all easter egg overlays) ===== */
.eggs-layer {
  position: fixed;
  inset: 0;
  z-index: 9999;
  pointer-events: none;
  overflow: hidden;
}

.sparkle-layer,
.fireworks-layer,
.confetti-layer,
.fireflies-layer,
.bloom-layer {
  position: absolute;
  inset: 0;
  pointer-events: none;
  overflow: hidden;
}

/* ===== Sparkle Burst (Double-tap) ===== */
.sparkle {
  position: absolute;
  border-radius: 50%;
  pointer-events: none;
  will-change: transform, opacity;
  transform: translateZ(0);
}

.sparkle-star {
  position: absolute;
  pointer-events: none;
  will-change: transform, opacity;
  transform: translateZ(0);
  font-size: 1rem;
  color: var(--color-gold);
}

/* ===== Hidden Message Toast ===== */
.hidden-message {
  position: fixed;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%) scale(0.8);
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  padding: 1.5rem 2rem;
  border-radius: 1rem;
  box-shadow: 0 8px 40px rgba(212, 122, 146, 0.2);
  border: 1px solid var(--color-rose-light);
  font-size: 1rem;
  color: var(--color-text);
  letter-spacing: 0.08em;
  text-align: center;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.4s, transform 0.4s;
  z-index: 10001;
}

.hidden-message.show {
  opacity: 1;
  transform: translate(-50%, -50%) scale(1);
}

/* ===== Milestone Toast ===== */
.milestone-toast {
  position: fixed;
  top: 3rem;
  left: 50%;
  transform: translateX(-50%) translateY(-20px);
  background: linear-gradient(135deg, var(--color-rose-light), var(--color-gold-light));
  padding: 0.8rem 1.5rem;
  border-radius: 2rem;
  box-shadow: 0 4px 20px rgba(212, 165, 116, 0.3);
  font-size: 0.85rem;
  color: var(--color-text);
  letter-spacing: 0.05em;
  text-align: center;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.4s, transform 0.4s;
  z-index: 10001;
  white-space: nowrap;
}

.milestone-toast.show {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}

/* ===== Love Carousel (Long-press title) ===== */
.love-carousel {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  z-index: 5;
  text-align: center;
  pointer-events: none;
  opacity: 0;
  transition: opacity 0.6s;
}

.love-carousel.show {
  opacity: 1;
}

.love-msg {
  display: block;
  font-size: clamp(0.9rem, 3vw, 1.2rem);
  color: var(--color-rose-dark);
  letter-spacing: 0.15em;
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%) scale(0.8);
  opacity: 0;
  transition: opacity 0.6s, transform 0.6s;
  white-space: nowrap;
  text-shadow: 0 1px 8px rgba(255,255,255,0.6);
  font-weight: 600;
}

.love-msg.active {
  opacity: 1;
  transform: translate(-50%, -50%) scale(1);
}

/* ===== Card Easter Egg (Long-press card) ===== */
.card-egg-text {
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  padding: 1rem 1.5rem;
  background: linear-gradient(0deg, rgba(212, 165, 116, 0.95), rgba(232, 160, 180, 0.9));
  color: var(--color-white);
  font-size: 0.85rem;
  text-align: center;
  letter-spacing: 0.08em;
  line-height: 1.6;
  transform: translateY(100%);
  opacity: 0;
  transition: transform 0.5s var(--transition-smooth), opacity 0.5s;
  pointer-events: none;
}

.card-egg-text.show {
  transform: translateY(0);
  opacity: 1;
}

/* ===== Card Ripple Effect ===== */
.card-ripple {
  position: absolute;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(232, 160, 180, 0.3) 0%, transparent 70%);
  pointer-events: none;
  transform: scale(0);
  animation: rippleExpand 0.8s ease-out forwards;
}

@keyframes rippleExpand {
  to {
    transform: scale(4);
    opacity: 0;
  }
}

/* ===== Fireflies ===== */
.firefly {
  position: absolute;
  width: 4px;
  height: 4px;
  border-radius: 50%;
  background: var(--color-gold);
  box-shadow: 0 0 6px 2px rgba(212, 165, 116, 0.4);
  pointer-events: none;
  will-change: transform, opacity;
  transform: translateZ(0);
}

/* ===== Confetti (Shake) ===== */
.confetti {
  position: absolute;
  width: 8px;
  height: 12px;
  pointer-events: none;
  will-change: transform, opacity;
  transform: translateZ(0);
}

/* ===== Fireworks (Scroll to bottom) ===== */
.firework-particle {
  position: absolute;
  width: 3px;
  height: 3px;
  border-radius: 50%;
  pointer-events: none;
  will-change: transform, opacity;
  transform: translateZ(0);
}

/* ===== Konami Bloom ===== */
.bloom-petal {
  position: absolute;
  pointer-events: none;
  will-change: transform, opacity;
  transform: translateZ(0);
  border-radius: 50%;
}

.bloom-overlay {
  position: fixed;
  inset: 0;
  background: radial-gradient(circle at center, rgba(245, 214, 208, 0.6), rgba(253, 246, 240, 0.9));
  z-index: 10000;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  transition: opacity 0.8s;
  pointer-events: none;
}

.bloom-overlay.show {
  opacity: 1;
  pointer-events: auto;
}

.bloom-text {
  font-size: clamp(1.5rem, 5vw, 2.5rem);
  font-weight: 900;
  color: var(--color-rose-dark);
  letter-spacing: 0.2em;
  text-shadow: 0 2px 20px rgba(212, 165, 116, 0.3);
  transform: scale(0.5);
  opacity: 0;
  transition: transform 1s var(--transition-smooth), opacity 0.8s;
}

.bloom-overlay.show .bloom-text {
  transform: scale(1);
  opacity: 1;
}

/* ===== Footer Easter Egg ===== */
.footer-egg {
  margin-top: 0.5rem;
  font-size: 0.72rem;
  opacity: 0.3;
  cursor: pointer;
  transition: opacity 0.3s;
  user-select: none;
  -webkit-user-select: none;
}

.footer-egg:hover {
  opacity: 0.7;
}

.footer-rainbow {
  background: linear-gradient(
    90deg,
    #e8a0b4, #f5d6d0, #d4a574, #e8c9a8,
    #d47a92, #e8a0b4, #f5d6d0, #d4a574
  );
  background-size: 200% 100%;
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  animation: rainbowShift 2s linear infinite;
}

@keyframes rainbowShift {
  0% { background-position: 0% 50%; }
  100% { background-position: 200% 50%; }
}

/* ===== Footer ===== */
footer {
  padding: 2rem 1.5rem;
  text-align: center;
  background: var(--color-text);
  color: var(--color-cream);
}

footer p {
  font-size: 0.9rem;
  letter-spacing: 0.1em;
  line-height: 2;
}

.footer-date {
  font-size: 0.78rem;
  opacity: 0.6;
  font-family: var(--font-script);
  letter-spacing: 0.15em;
}

/* ===== Responsive: Tablet & up ===== */
@media (min-width: 600px) {
  :root {
    --section-padding: 5rem 2.5rem;
  }

  .section-title {
    font-size: 2rem;
  }

  .letter-card {
    padding: 3rem 2.5rem;
  }

  .letter-body p {
    font-size: 1rem;
  }

  .gallery-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1.5rem;
    max-width: 56rem;
  }

  .card-illustration {
    height: 8rem;
  }

  .gratitude-text {
    font-size: 1.1rem;
  }
}

@media (min-width: 900px) {
  #hero {
    min-height: 100vh;
  }

  .hero-title {
    font-size: 4rem;
  }

  .card-illustration {
    height: 10rem;
  }
}

/* ===== Mobile-specific Performance ===== */
@media (max-width: 599px) {
  /* Reduce shadow complexity on mobile */
  .letter-card {
    box-shadow: 0 2px 12px var(--color-shadow);
  }

  .memory-card {
    box-shadow: 0 2px 10px var(--color-shadow);
  }

  /* Simplify gradient on hero for mobile GPU */
  #hero {
    background-size: 150% 150%;
    animation-duration: 16s;
  }

  /* Reduce transition count on mobile */
  .memory-card {
    transition: transform 0.3s ease;
  }
}

/* ===== Reduced Motion ===== */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }

  html {
    scroll-behavior: auto;
  }

  .reveal {
    opacity: 1;
    transform: none;
  }

  .petal {
    display: none;
  }

  [data-content-visibility] {
    content-visibility: visible;
  }
}

/* ===== Selection ===== */
::selection {
  background: var(--color-rose);
  color: var(--color-white);
}