:root {
  --nav-bg: rgba(17, 17, 17, 0.85);
  --nav-accent: #fcd34d; /* Warm yellow/amber */
  --nav-text: #e5e7eb;
  --nav-text-muted: #9ca3af;
  --nav-hover-bg: rgba(255, 255, 255, 0.05);
  --glass-border: rgba(255, 255, 255, 0.1);
  --transition-speed: 0.3s;
}

.sidepanel {
  height: 100%;
  width: 0;
  position: fixed;
  z-index: 1000;
  top: 0;
  left: 0;
  background-color: var(--nav-bg);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-right: 1px solid var(--glass-border);
  overflow-x: hidden;
  overflow-y: auto; /* Allow vertical scrolling for long menus */
  padding-top: 80px;
  transition: width var(--transition-speed) cubic-bezier(0.4, 0, 0.2, 1);
  box-shadow: 10px 0 30px rgba(0, 0, 0, 0.5);
  max-width: 100vw; /* Prevent overflow on tiny screens */
}

.sidepanel.is-open {
  width: min(300px, 85vw); /* Responsive width */
}

/* Sidebar List Structure */
.nav-list {
  list-style: none;
  padding: 0;
  margin: 0;
}

.nav-item {
  border-bottom: 1px solid rgba(255, 255, 255, 0.03);
}

.nav-link {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 24px;
  text-decoration: none;
  color: var(--nav-text);
  font-size: 1.1rem;
  font-weight: 500;
  transition: all var(--transition-speed);
  cursor: pointer;
}

.nav-link:hover {
  background: var(--nav-hover-bg);
  color: var(--nav-accent);
}

.nav-link i {
  font-size: 1.2rem;
  transition: transform var(--transition-speed);
}

/* Dropdown styling */
.dropdown-container {
  max-height: 0;
  overflow: hidden;
  background: rgba(0, 0, 0, 0.2);
  transition: max-height var(--transition-speed) ease-out;
}

.nav-item.is-active .dropdown-container {
  max-height: 500px; /* Large enough for content */
}

.nav-item.is-active .chevron {
  transform: rotate(180deg);
}

.dropdown-list {
  list-style: none;
  padding: 8px 0;
  margin: 0;
}

.dropdown-item a {
  display: block;
  padding: 10px 48px;
  text-decoration: none;
  color: var(--nav-text-muted);
  font-size: 0.95rem;
  transition: color var(--transition-speed);
}

.dropdown-item a:hover {
  color: var(--nav-accent);
}

/* Close button */
.sidepanel .closebtn {
  position: absolute;
  top: 15px;
  right: 20px;
  font-size: 32px;
  color: var(--nav-text-muted);
  cursor: pointer;
  transition: color var(--transition-speed);
  background: none;
  border: none;
}

.sidepanel .closebtn:hover {
  color: #ef4444; /* Soft red */
}

/* Open button */
.openbtn {
  position: fixed;
  top: 20px;
  left: 20px;
  z-index: 900;
  font-size: 24px;
  cursor: pointer;
  background: var(--nav-bg);
  color: white;
  padding: 12px;
  border: 1px solid var(--glass-border);
  border-radius: 12px;
  backdrop-filter: blur(8px);
  transition: transform var(--transition-speed);
  display: flex;
  align-items: center;
  justify-content: center;
}

.openbtn:hover {
  transform: scale(1.05);
  background: #222;
}

/* --- Mobile Adjustments --- */
@media (max-width: 768px) {
  .openbtn {
    top: 15px;
    left: 15px;
    padding: 10px;
    font-size: 20px;
    border-radius: 10px;
  }
  
  .sidepanel {
    padding-top: 60px;
  }
}