:root {
  --bg-color: #fdfbf7;
  /* Warm off-white */
  --text-color: #2c3e50;
  /* Dark slate blue for text */
  --accent-color: #e67e22;
  /* Soft orange for highlights */
  --card-bg: #ffffff;
  --card-shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
  --card-hover-shadow: 0 10px 15px rgba(0, 0, 0, 0.1);
  --font-main: 'Noto Serif Bengali', serif;
  --spacing-unit: 1rem;
  --border-radius: 12px;
  --primary-color: #34495e;
  --link-color: #2980b9;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

body {
  font-family: var(--font-main);
  background-color: var(--bg-color);
  color: var(--text-color);
  line-height: 1.6;
  margin: 0;
  padding: 0;
  -webkit-font-smoothing: antialiased;
}

a {
  color: var(--link-color);
  text-decoration: none;
  transition: color 0.2s ease;
}

a:hover {
  color: var(--accent-color);
}

/* Navbar */
.navbar {
  background-color: var(--card-bg);
  box-shadow: var(--card-shadow);
  padding: 1rem 0;
  position: sticky;
  top: 0;
  z-index: 1000;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

.navbar-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.navbar-brand {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--primary-color);
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.navbar-brand img {
  height: 32px;
  width: auto;
}

.btn-github {
  background-color: var(--primary-color);
  color: white;
  padding: 0.5rem 1rem;
  border-radius: 20px;
  font-size: 0.9rem;
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  transition: background-color 0.2s ease, transform 0.1s ease;
}

.btn-github:hover {
  background-color: #2c3e50;
  transform: translateY(-1px);
  color: white;
}

/* Main Content */
main {
  padding: 3rem 0;
}

.grid {
  /* Masonry handles layout, so we just need to ensure the container is ready */
  margin: 0 auto;
}

.grid-sizer,
.grid-item {
  width: 30%;
  /* 3 columns with 30px gutter (approx 3.33% gap) */
  margin-bottom: 2rem;
}

@media (max-width: 992px) {

  .grid-sizer,
  .grid-item {
    width: 48%;
  }
}

@media (max-width: 576px) {

  .grid-sizer,
  .grid-item {
    width: 100%;
  }
}

/* Category Card */
.category-card {
  background: var(--card-bg);
  border-radius: var(--border-radius);
  box-shadow: var(--card-shadow);
  overflow: hidden;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
  display: flex;
  flex-direction: column;
}

.category-card:hover {
  box-shadow: var(--card-hover-shadow);
}

.category-header {
  background-color: var(--primary-color);
  color: white;
  padding: 1rem 1.5rem;
  font-size: 1.2rem;
  font-weight: 600;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.category-content {
  padding: 0;
  list-style: none;
  margin: 0;
}

.resource-link {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1rem 1.5rem;
  border-bottom: 1px solid #f0f0f0;
  color: var(--text-color);
  transition: background-color 0.2s ease;
}

.resource-link:last-child {
  border-bottom: none;
}

.resource-link:hover {
  background-color: #f8f9fa;
  color: var(--link-color);
  padding-left: 1.75rem;
  /* Subtle slide effect */
}

.icon-external {
  font-size: 0.8rem;
  opacity: 0.5;
}

/* Footer (if needed) */
footer {
  text-align: center;
  padding: 2rem;
  color: #7f8c8d;
  font-size: 0.9rem;
}

/* Responsive adjustments */
@media (max-width: 768px) {
  .grid {
    grid-template-columns: 1fr;
  }

  .navbar-brand span {
    font-size: 1.2rem;
  }
}