body {
  font-family: Arial, sans-serif;
  padding: 15px;
  background-color: #f5f5f5;
  text-align: center;
  margin: 0;
}

.tit-name {
  background: linear-gradient(to right, #3a86ff, #8338ec);
  color: #fff;
  padding: 12px 20px;
  border-radius: 8px;
  text-align: left;
  margin: 15px auto 20px;
  width: fit-content;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.2);
}

.viewer-container {
  max-width: 900px;
  margin: 20px auto;
  position: relative;
}

.main-image {
  display: block;
  width: 100%;
  height: auto;
  border-radius: 12px;
  border: 3px solid black;
  box-shadow: 0 6px 25px rgba(0, 0, 0, 0.3);
  transition: all 0.3s ease-in-out;
  object-fit: cover;
  aspect-ratio: 16 / 9;
}

.nav-symbol {
  font-size: 30px;
  cursor: pointer;
  background-color: rgba(0, 0, 0, 0.4);
  color: white;
  padding: 8px 14px;
  border-radius: 50%;
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  z-index: 5;
  user-select: none;
}

.nav-symbol:hover {
  background-color: rgba(0, 0, 0, 0.7);
}

.nav-left {
  left: 10px;
}

.nav-right {
  right: 10px;
}

.dot-container {
  margin-top: 10px;
  text-align: center;
}

.dot {
  height: 8px;
  width: 8px;
  margin: 0 5px;
  background-color: gray;
  border-radius: 50%;
  display: inline-block;
  transition: background-color 0.3s ease;
  cursor: pointer;
}

.dot.active {
  background-color: black;
}

.back-button {
  margin-top: 20px;
  text-align: center;
}

.back-button a {
  text-decoration: none;
  font-size: 18px;
  color: white;
  background-color: black;
  padding: 8px 16px;
  border-radius: 6px;
}

/* Responsive adjustments */
@media (max-width: 768px) {
  .viewer-container {
    margin: 15px;
  }

  .main-image {
    aspect-ratio: 1 / 1;
    height: auto;
  }

  .nav-symbol {
    font-size: 24px;
    padding: 6px 10px;
  }

  .nav-left {
    left: 5px;
  }

  .nav-right {
    right: 5px;
  }
}

@media (max-width: 480px) {
  .tit-name {
    font-size: 1.3em;
    padding: 10px 15px;
    margin-bottom: 15px;
  }

  .back-button a {
    font-size: 16px;
    padding: 6px 12px;
  }

  .nav-symbol {
    font-size: 20px;
    padding: 5px 8px;
  }
}