body {
  margin: 0;
  background: #000;
  color: #fff;
  font-family: 'Lexend';
  font-weight: 100;
}
#threejs-canvas {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 1;
}
#controls {
  position: absolute;
  top: 20px;
  left: 50%;
  transform: translateX(-50%);
  z-index: 2;
  background: rgba(0,0,0,0.7);
  padding: 10px 20px;
  border-radius: 10px;
}
#text-select {
  font-size: 1rem;
  padding: 5px 10px;
  border-radius: 5px;
  border: none;
}
#yt-audio {
  width: 0;
  height: 0;
  border: none;
  position: absolute;
  left: -9999px;
}

/* Màn loading với nút trái tim */
.loading-screen {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: radial-gradient(ellipse at bottom, #1B2735 0%, #090A0F 100%);
  display: flex;
  justify-content: center;
  align-items: center;
  z-index: 9999;
  transition: opacity 0.5s ease-in-out;
  overflow: hidden;
}

/* Hiệu ứng sao lấp lánh */
.loading-screen::before,
.loading-screen::after {
  content: "";
  position: absolute;
  width: 3px;
  height: 3px;
  background: white;
  box-shadow: 
    0 0 10px #fff,
    0 0 20px #fff,
    0 0 30px #fff;
  animation: twinkle 1s infinite;
}

.loading-screen::before {
  right: 40%;
  top: 40%;
  animation-delay: .4s;
}

.loading-screen::after {
  left: 30%;
  top: 60%;
  animation-delay: .6s;
}

@keyframes twinkle {
  0%, 100% {
    opacity: 1;
  }
  50% {
    opacity: 0.3;
  }
}

.star {
  position: absolute;
  width: 2px;
  height: 2px;
  background: #fff;
  border-radius: 50%;
  animation: twinkle 1.5s infinite;
}

.heart-button {
  background: none;
  border: none;
  cursor: pointer;
  transform-origin: center;
  animation: pulse 1.5s infinite;
  transition: all 0.5s ease;
  position: relative;
  z-index: 2;
}

.heart-button:hover {
  transform: scale(1.1) translateY(-10px);
}

.heart-button svg {
  width: 100px;
  height: 100px;
  filter: drop-shadow(0 0 15px rgba(255, 0, 0, 0.7));
}

.heart-button path {
  fill: #ac2c2c;
}

/* Hiệu ứng bay lên khi click */
.heart-button.clicked {
  animation: float-away 1.5s ease-in forwards;
}

@keyframes float-away {
  0% {
    transform: scale(1) translateY(0);
    opacity: 1;
  }
  50% {
    transform: scale(1.2) translateY(-100px);
    opacity: 0.7;
  }
  100% {
    transform: scale(1.5) translateY(-300px);
    opacity: 0;
  }
}

@keyframes pulse {
  0% {
    transform: scale(1);
  }
  50% {
    transform: scale(1.1);
  }
  100% {
    transform: scale(1);
  }
}

.loading-text {
  position: absolute;
  bottom: 20%;
  left: 50%;
  transform: translateX(-50%);
  color: white;
  font-family: 'Playpen Sans', cursive;
  font-size: 1.2em;
  text-align: center;
  text-shadow: 0 0 10px rgba(255, 255, 255, 0.5);
  z-index: 2;
}

/* Hiệu ứng fade out mượt mà hơn */
.fade-out {
  opacity: 0;
  pointer-events: none;
  transition: opacity 1s ease-in-out;
}

/* Hiệu ứng fade in cho body */
.fade-in {
  opacity: 0;
  animation: fade-in 2s ease-in forwards;
  animation-delay: 0.5s;
}

@keyframes fade-in {
  from {
    opacity: 0;
  }
  to {
    opacity: 1;
  }
}