body {
  margin: 0;
  background: linear-gradient(to bottom, #ffe6f2, #fff0fa);
  font-family: "Pacifico", cursive;
  overflow-x: hidden; /* prevent horizontal scroll */
}

/* Envelope Screen */
.container {
  text-align: center;
  margin-top: 60px;
  transition: opacity 1s ease;
}

h1 {
  font-size: 3rem;
  color: #ff4da6;
  text-shadow: 2px 2px white;
}

.subtitle {
  font-size: 1.3rem;
  color: #ff80bf;
}

/* Envelope */
.envelope {
  width: 360px;
  height: 220px;
  background: #ffb6d9;
  margin: 70px auto;
  position: relative;
  border-radius: 25px;
  cursor: pointer;
  box-shadow: 0 12px 30px rgba(0,0,0,0.25);
  transition: 0.3s;
}

.envelope:hover {
  transform: scale(1.04);
}

.top {
  position: absolute;
  width: 0;
  height: 0;
  border-left: 180px solid transparent;
  border-right: 180px solid transparent;
  border-bottom: 120px solid #ff80bf;
  top: 0;
  left: 0;
}

.kitty {
  position: absolute;
  top: 85px;
  left: 50%;
  transform: translateX(-50%);
  font-size: 3rem;
}

.bow {
  position: absolute;
  top: 130px;
  left: 50%;
  transform: translateX(-50%);
  font-size: 2.3rem;
}

/* Fullscreen Letter */
.fullscreen-letter {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: linear-gradient(to bottom, #fff0fa, #ffe6f2);
  padding: 60px 20px;
  box-sizing: border-box;
  text-align: center;
  overflow-y: auto;
  opacity: 0;
  visibility: hidden;
  transition: opacity 1.5s ease;
}

.fullscreen-letter h2 {
  font-size: 2.6rem;
  color: #ff4da6;
}

.fullscreen-letter p {
  font-size: 1.2rem;
  max-width: 700px;
  margin: 15px auto;
  line-height: 1.7;
  color: #444;
}

.signature {
  font-size: 1.5rem;
  color: #ff4da6;
  margin-top: 25px;
}

/* Valentine Button */
.valentine-btn {
  margin-top: 40px;
  padding: 15px 25px;
  border: none;
  border-radius: 30px;
  background: #ff4da6;
  color: white;
  font-size: 1.2rem;
  cursor: pointer;
  transition: 0.3s;
}

.valentine-btn:hover {
  transform: scale(1.05);
}

/* Hidden Yes Message */
.yes-message {
  margin-top: 25px;
  font-size: 1.5rem;
  color: #ff4da6;
  display: none;
}

/* Stickers */
.sticker {
  position: absolute;
  width: 100px;
  z-index: 10;
  animation: floatStickers 6s infinite alternate ease-in-out;
}

.sticker1 { top: 10px; left: 15px; }
.sticker2 { bottom: 20px; right: 20px; }
.sticker3 { top: 50%; left: 80%; }

@keyframes floatStickers {
  0% { transform: translateY(0) rotate(0deg); }
  50% { transform: translateY(-15px) rotate(5deg); }
  100% { transform: translateY(0) rotate(-5deg); }
}