body {
  margin: 0;
  font-family: "Noto Sans JP", sans-serif;
  background: #1a1a1a;
  color: #fff;
  overflow-x: hidden;
}
body.white-bg { background: #fdfdfd; color: #000; }

.back-btn {
  position: fixed;
  top: 25px;
  left: 35px;
  font-size: 1.2rem;
  font-weight: 900;
  text-decoration: none;
  color: #fff;
  z-index: 10000;
  transition: all 0.5s ease, transform 0.3s ease;
}
body.white-bg .back-btn { color: black; }
body.dark-mode .back-btn { color: white; }

header {
  text-align: center;
  padding: 70px 20px 20px 20px;
  font-size: 2rem;
  font-weight: bold;
  animation: float 3s ease-in-out infinite alternate;
}

#search-container {
  text-align: center;
  margin-bottom: 30px;
  animation: float 3s ease-in-out infinite alternate-reverse;
}

#search-input {
  padding: 8px 12px;
  font-size: 1rem;
  border-radius: 12px;
  border: 2px solid #b278cb;
  outline: none;
  background: rgba(255,255,255,0.05);
  color: #fff;
  transition: all 0.3s ease;
}
#search-input:focus {
  border-color: #ffb6c1;
  background: rgba(255,255,255,0.15);
}

.sort-btn {
  margin-left: 10px;
  padding: 8px 16px;
  border-radius: 12px;
  border: none;
  cursor: pointer;
  font-weight: bold;
  background: linear-gradient(145deg, #b278cb, #ffb6c1);
  color: #fff;
  box-shadow: 0 4px 15px rgba(0,0,0,0.3);
  transition: transform 0.3s ease, box-shadow 0.3s ease;
}
.sort-btn:hover {
  transform: scale(1.05);
  box-shadow: 0 6px 25px rgba(0,0,0,0.5);
}

.gallery {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 40px;
  padding-bottom: 80px;
}

.art-card {
  background: rgba(255,255,255,0.05);
  border-radius: 12px;
  overflow: hidden;
  width: 280px;
  text-align: center;
  cursor: pointer;
  transition: transform 0.4s ease, box-shadow 0.4s ease;
  animation: float 3s ease-in-out infinite alternate;
}
.art-card:hover {
  transform: scale(1.05);
  box-shadow: 0 10px 30px rgba(255,255,255,0.3);
}

.art-card img {
  width: 100%;
  display: block;
}

.art-info {
  padding: 10px;
}
.art-title {
  font-weight: bold;
  font-size: 1.1rem;
  margin-bottom: 4px;
}
.art-creator, .art-date {
  font-size: 0.9rem;
  opacity: 0.8;
  margin-bottom: 2px;
}
.art-desc {
  font-size: 0.9rem;
  opacity: 0.7;
}

@keyframes float {
  0% { transform: translateY(0px); }
  100% { transform: translateY(-8px); }
}

/* 鼠标圆点 */
#cursor-dot {
  position: fixed;
  top: 0;
  left: 0;
  width: 20px;
  height: 20px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(178,120,203,0.8), rgba(255,182,193,0.6));
  pointer-events: none;
  transform: translate(-50%, -50%);
  transition: width 0.15s ease, height 0.15s ease, background 0.25s ease, transform 0.25s ease;
  z-index: 2147483647;
}
#cursor-dot.active {
  border-radius: 0%;
  transform: translate(-50%, -50%) rotate(45deg) scale(1.5);
}