:root {
  --color-light: #ffffff;
  --color-dark: #121212;
  --color-accent: #bb86fc;
  --color-text-light: #000000;
  --color-text-dark: #ffffff;
}

body {
  font-family: Arial, sans-serif;
  margin: 0;
  padding: 0;
  transition: background-color 0.5s, color 0.5s;
}

.light-theme {
  background-color: var(--color-light);
  color: var(--color-text-light);
}

.dark-theme {
  background-color: var(--color-dark);
  color: var(--color-text-dark);
}

header {
  background-color: var(--color-accent);
  padding: 10px;
  text-align: center;
  font-size: 24px;
}

nav {
  display: flex;
  justify-content: center;
  background-color: var(--color-accent);
}

nav button {
  background: none;
  border: none;
  color: white;
  padding: 14px 20px;
  cursor: pointer;
  font-size: 18px;
}

nav button:hover {
  background-color: #3700b3;
}

.main-content {
  display: none;
  padding: 20px;
  animation: fadeIn 1s ease-in-out;
}

.active {
  display: block;
}

.loading-screen {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  height: 100vh;
  background-color: var(--color-dark);
  color: var(--color-text-dark);
}

.loading-spinner {
  border: 8px solid #f3f3f3;
  border-top: 8px solid var(--color-accent);
  border-radius: 50%;
  width: 60px;
  height: 60px;
  animation: spin 2s linear infinite;
  margin: 20px;
}

.loading-dots {
  display: flex;
  gap: 5px;
}

.loading-dot {
  width: 10px;
  height: 10px;
  background-color: var(--color-accent);
  border-radius: 50%;
  animation: bounce 1.5s infinite ease-in-out;
}

.loading-dot:nth-child(2) {
  animation-delay: 0.3s;
}

.loading-dot:nth-child(3) {
  animation-delay: 0.6s;
}

@keyframes spin {
  0% { transform: rotate(0deg); }
  100% { transform: rotate(360deg); }
}

@keyframes bounce {
  0%, 80%, 100% { transform: scale(0); }
  40% { transform: scale(1.0); }
}

@keyframes fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

@media (max-width: 600px) {
  nav button {
    padding: 10px;
    font-size: 16px;
  }
}