:root {
  --color-bg: #0d1117;
  --color-card: #161b22;
  --color-accent: #1f6feb;
  --color-accent-light: #58a6ff;
  --color-text: #f0f6fc;
  --color-border: #30363d;
  --color-muted: #9da9b9;
  --radius: 12px;
  --transition: 0.3s ease;
}

:root[data-theme="light"] {
  --color-bg: #f5f7fa;
  --color-card: #ffffff;
  --color-accent: #0070f3;
  --color-accent-light: #409cff;
  --color-text: #0d1117;
  --color-border: #d0d7de;
  --color-muted: #555;
}

body {
  background-color: var(--color-bg);
  color: var(--color-text);
  font-family: "Poppins", sans-serif;
  line-height: 1.6;
  margin: 0;
  padding: 0;
  transition: background-color var(--transition), color var(--transition);
}


header {
  background-color: var(--color-card);
  border-bottom: 1px solid var(--color-border);
  box-shadow: 0 2px 10px rgba(0, 0, 0, 0.4);
}


.navbar-dark .navbar-nav .nav-link {
  color: var(--color-muted);
  font-weight: 500;
  transition: color var(--transition);
}

.navbar-dark .navbar-nav .nav-link:hover,
.navbar-dark .navbar-nav .nav-link.active {
  color: var(--color-accent);
}

.navbar-toggler {
  border-color: var(--color-border);
}


section {
  background-color: var(--color-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 2rem;
  box-shadow: 0 4px 15px rgba(0, 0, 0, 0.3);
  opacity: 0;
  transform: translateY(20px);
  animation: fadeInUp 0.8s var(--transition) forwards;
}

@keyframes fadeInUp {
  from { transform: translateY(30px); opacity: 0; }
  to { transform: translateY(0); opacity: 1; }
}

h2, h3 {
  color: var(--color-accent-light);
}


.intro-card {
  background-color: var(--color-card);
  padding: 2rem;
  border-radius: var(--radius);
  border: 1px solid var(--color-border);
  box-shadow: 0 4px 15px rgba(0, 0, 0, 0.4);
  color: var(--color-text);
  transition: transform 0.3s ease, box-shadow 0.3s ease, background-color 0.3s ease;
  height: 100%; 
}

.intro-card:hover {
  background-color: rgba(31, 111, 235, 0.1);
  border-color: var(--color-accent);
  transform: translateY(-5px);
  color: var(--color-text); 
}

.intro-card.active {
  transform: scale(1.05);
  box-shadow: 0 8px 25px rgba(31, 111, 235, 0.5);
  background-color: rgba(31, 111, 235, 0.2);
}

.intro-card h3 {
  color: var(--color-accent-light);
  font-size: 1.4rem;
  margin-bottom: 1rem;
}

.intro-card p {
  font-size: 1rem;
  opacity: 0.9;
}


footer {
  text-align: center;
  padding: 1.5rem;
  color: var(--color-muted);
  border-top: 1px solid var(--color-border);
  background-color: var(--color-card);
  margin-top: 3rem;
}

footer a {
  color: var(--color-accent-light);
  text-decoration: none;
}


.btn-custom {
  background-color: var(--color-accent);
  color: white;
  border: none;
  border-radius: var(--radius);
}
.btn-custom:hover {
  background-color: var(--color-accent-light);
  color: white;
}