/* Full screen layout */
body {
  margin: 0;
  padding: 0;
  width: 100vw;
  height: 100vh;
  font-family: Arial, sans-serif;
  overflow: hidden;
  display: flex;
  justify-content: center;
  align-items: center;

  /* 🎉 Animated birthday gradient */
  background: linear-gradient(135deg, #ff9a9e, #fad0c4, #fbc2eb);
  background-size: 400% 400%;
  animation: gradientBG 8s ease infinite;
}

/* 🎨 Background animation */
@keyframes gradientBG {
  0% { background-position: 0% 50%; }
  50% { background-position: 100% 50%; }
  100% { background-position: 0% 50%; }
}

/* Main container */
#app {
  width: 100%;
  height: 100%;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
}

/* Page content */
.page {
  text-align: center;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  height: 100%;
  gap: 5px;
}

/* Title and subtitle animations */
h1 {
  font-size: 50px;
  margin: 0;
  animation: bounce 0.8s infinite alternate, shake 1.5s infinite;
}

h2 {
  margin-top: 50px;
  font-size: 45px;
  animation: bounce 1s infinite alternate;
}

/* Sticker */
.sticker {
  display: inline-block;
  max-width: 100vw;
  max-height: 50vh;
  animation: wiggle 0.5s infinite;
  background: transparent !important;
}

.sticker img {
  width: 100%;
  height: 100%;
  object-fit: contain;
  display: block;
  pointer-events: none;
}

/* Buttons */
.buttons button {
  padding: 12px 30px;
  margin: 20px;
  font-size: 20px;
  border: none;
  border-radius: 10px;
  cursor: pointer;
  animation: pulse 0.8s infinite;
}

/* 🎈 Floating balloons */
.balloon {
  position: absolute;
  bottom: -100px;
  width: 40px;
  height: 50px;
  border-radius: 50%;
  animation: floatUp linear infinite;
}

@keyframes floatUp {
  0% { transform: translateY(0); opacity: 1; }
  100% { transform: translateY(-120vh); opacity: 0; }
}

/* Animations */
@keyframes bounce {
  from { transform: translateY(0); }
  to { transform: translateY(-15px); }
}

@keyframes wiggle {
  0% { transform: rotate(-5deg); }
  50% { transform: rotate(5deg); }
  100% { transform: rotate(-5deg); }
}

@keyframes pulse {
  0% { transform: scale(1); }
  50% { transform: scale(1.25); }
  100% { transform: scale(1); }
}

@keyframes shake {
  0% { transform: translateX(0); }
  25% { transform: translateX(-6px); }
  50% { transform: translateX(6px); }
  75% { transform: translateX(-6px); }
  100% { transform: translateX(0); }
}

@keyframes angryShake {
  0% { transform: translate(0, 0); }
  20% { transform: translate(-10px, 5px); }
  40% { transform: translate(10px, -5px); }
  60% { transform: translate(-10px, 5px); }
  80% { transform: translate(10px, -5px); }
  100% { transform: translate(0, 0); }
}

.angry {
  animation: angryShake 0.2s infinite;
}

/* 💖 Love Page / Envelope Page */
.love-page, .envelope-page {
  width: 100%;
  height: 100%;
  display: flex;
  justify-content: center;
  align-items: center;
  flex-direction: column;
}

/* Slideshow images */
.slideshow img {
  width: 250px;
  height: 300px;
  object-fit: cover;
  border-radius: 20px;
  margin-top: 20px;
  box-shadow: 0 10px 25px rgba(0,0,0,0.3);
  animation: fadeIn 0.5s ease;
}

/* Envelope */
.envelope {
  position: relative;
  width: 320px;
  height: 200px;
  cursor: pointer;
}

.envelope-body {
  position: absolute;
  width: 100%;
  height: 100%;
  background: #ff4d6d;
  border-radius: 10px;
  z-index: 1;
}

.envelope-flap {
  position: absolute;
  top: 0;
  left: 0;
  width: 0;
  height: 0;
  border-left: 160px solid transparent;
  border-right: 160px solid transparent;
  border-bottom: 100px solid #ff85a2;
  z-index: 2;
  transform-origin: top;
  transition: transform 0.5s ease;
}

.envelope-text {
  position: absolute;
  width: 100%;
  top: 65%;
  text-align: center;
  font-family: 'Great Vibes', cursive;
  font-size: 32px;
  color: white;
  z-index: 3;
}

/* Letter (FULL SCREEN like original) */
.letter {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;

  display: flex;
  justify-content: center;
  align-items: center;

  background: #e8a19a;
}

.letter img {
  width: 95vw;
  height: 95vh;
  object-fit: contain;
  border-radius: 20px;
  box-shadow: 0 20px 50px rgba(0,0,0,0.3);
}

/* Hidden */
.hidden {
  display: none;
}

/* Buttons */
button {
  padding: 16px 40px;
  font-size: 22px;
  border-radius: 12px;
  background: white;
  color: #ff4d6d;
  border: none;
  cursor: pointer;
}

.back-btn {
  position: fixed;
  top: 20px;
  left: 20px;
  font-size: 28px;
  background: transparent;
  border: none;
  cursor: pointer;
  color: white;
  z-index: 999;
}

/* Animations */
@keyframes fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

@keyframes fadeInUp {
  from { opacity: 0; transform: translateY(30px); }
  to { opacity: 1; transform: translateY(0); }
}