body {
  font-family: Arial, sans-serif;
  background: #f5f5f5;
  margin: 0;
  padding: 0;
}

header {
  background: #0984e3;
  color: white;
  text-align: center;
  padding: 15px 0;
  box-shadow: 0 2px 5px rgba(0,0,0,0.2);
}

header h1 { margin: 0; font-size: 24px; }

nav {
  background: #74b9ff;
  text-align: center;
  padding: 10px 0;
}

nav a, .btn {
  color: white;
  text-decoration: none;
  margin: 0 8px;
  font-weight: bold;
  background: #0984e3;
  padding: 8px 14px;
  border-radius: 5px;
  border: none;
  cursor: pointer;
}
nav a:hover, .btn:hover { background: #065cb1; }

.container {
  max-width: 1200px;
  margin: 20px auto;
  background: #fff;
  border-radius: 10px;
  box-shadow: 0 0 10px rgba(0,0,0,0.2);
  overflow: hidden;
  display: flex;
  flex-direction: row;
}

/* Thumbnails */
#thumbs {
  width: 120px;
  background: #f1f1f1;
  overflow-y: auto;
  padding: 10px 5px;
  border-right: 2px solid #ddd;
}
#thumbs img {
  width: 100%;
  border-radius: 5px;
  margin-bottom: 8px;
  cursor: pointer;
  opacity: 0.6;
  transition: transform 0.2s, opacity 0.2s;
}
#thumbs img.active-thumb {
  opacity: 1;
  transform: scale(1.05);
  border: 2px solid #0984e3;
}

/* Viewer */
#viewer-wrapper { flex: 1; padding: 10px; text-align: center; }
#viewer img {
  width: 100%;
  border-radius: 10px;
  display: none;
  transition: transform 0.3s ease;
 /* max-height: 90vh;*/
  object-fit: contain;
}
#viewer img.active { display: block; }

#controls {
  margin: 10px 0;
}
#controls button {
  background: #0984e3;
  color: white;
  padding: 10px 15px;
  border: none;
  border-radius: 5px;
  margin: 0 5px;
  cursor: pointer;
}
#controls button:hover { background: #065cb1; }

.download-section { margin-top: 20px; padding: 10px; }
.download-btn {
  background: #27ae60;
  color: white;
  font-weight: bold;
  padding: 12px 20px;
  border-radius: 8px;
  border: none;
  text-decoration: none;
  display: inline-block;
  transition: background 0.3s;
}
.download-btn:hover { background: #1e8449; }

#calendarPopup {
  display: none;
  position: fixed;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  background: #fff;
  border: 2px solid #0984e3;
  padding: 20px;
  border-radius: 10px;
  box-shadow: 0 0 10px rgba(0,0,0,0.3);
  z-index: 999;
}

#admin-login {
  position: fixed;
  top: 10px;
  right: 10px;
  background: #636e72;
  color: white;
  padding: 8px 14px;
  border-radius: 5px;
  text-decoration: none;
}
#admin-login:hover { background: #2d3436; }

/* Mobile */
@media (max-width: 768px) {
  .container { flex-direction: column; }
  #thumbs {
    width: 100%;
    display: flex;
    flex-direction: row;
    overflow-x: auto;
    border-right: none;
    border-top: 2px solid #ddd;
    padding: 10px;
  }
  #thumbs img { width: 70px; margin-right: 8px; }
  #viewer img { max-height: 80vh; }
  header h1 { font-size: 20px; }
  #controls button { padding: 8px 12px; font-size: 14px; }
}