:root {
  --primary-color: #2d6a4f;
  --primary-dark: #1b4332;
  --primary-light: #40916c;
  --secondary-color: #52b788;
  --accent-color: #74c69d;
  --text-dark: #081c15;
  --text-muted: #475569;
  --bg-light: #f8fafc;
  --white: #ffffff;
  --shadow-sm: 0 2px 4px rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 24px;
  --radius-full: 9999px;
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: "Inter", sans-serif;
  background-color: var(--bg-light);
  color: var(--text-dark);
  scroll-behavior: smooth;
  line-height: 1.6;
}

/* custom navbar & brand */
.navbar {
  backdrop-filter: blur(10px);
  background-color: rgba(255, 255, 255, 0.8) !important;
  border-bottom: 1px solid rgba(0, 0, 0, 0.05);
}

.navbar-brand {
  font-weight: 800;
  font-size: 1.5rem;
  letter-spacing: -0.5px;
  background: linear-gradient(135deg, var(--primary-dark) 0%, var(--primary-color) 100%);
  background-clip: text;
  -webkit-background-clip: text;
  color: transparent;
}

.nav-link {
  font-weight: 600;
  color: var(--text-dark);
  transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  padding: 0.5rem 1rem !important;
  border-radius: var(--radius-sm);
}

.nav-link:hover {
  color: var(--primary-color);
  background-color: rgba(45, 106, 79, 0.05);
}

.nav-item .active {
  color: var(--primary-color) !important;
  background-color: rgba(45, 106, 79, 0.1);
}

/* hero section */
.hero-section {
  background: radial-gradient(circle at top right, rgba(82, 183, 136, 0.1), transparent),
              radial-gradient(circle at bottom left, rgba(27, 67, 50, 0.05), transparent),
              var(--white);
  padding: 6rem 0 4rem 0;
  position: relative;
  overflow: hidden;
}

.hero-section::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, rgba(0,0,0,0.05), transparent);
}

.impact-badge {
  background-color: var(--primary-dark);
  color: var(--white);
  border-radius: var(--radius-full);
  padding: 0.4rem 1.2rem;
  font-weight: 600;
  font-size: 0.8rem;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.btn-primary-custom {
  background: var(--primary-color);
  color: var(--white);
  border: none;
  padding: 0.8rem 2rem;
  font-weight: 600;
  border-radius: var(--radius-full);
  transition: all 0.3s ease;
  box-shadow: 0 4px 12px rgba(45, 106, 79, 0.2);
}

.btn-primary-custom:hover {
  background: var(--primary-dark);
  color: var(--white);
  transform: translateY(-2px);
  box-shadow: 0 8px 20px rgba(45, 106, 79, 0.3);
}

.btn-outline-custom {
  border: 2px solid var(--primary-color);
  color: var(--primary-color);
  padding: 0.8rem 2rem;
  font-weight: 600;
  border-radius: var(--radius-full);
  background: transparent;
  transition: all 0.3s ease;
}

.btn-outline-custom:hover {
  background: var(--primary-color);
  color: var(--white);
  transform: translateY(-2px);
}

.card-article {
  border: 1px solid rgba(0,0,0,0.05);
  border-radius: var(--radius-md);
  background: var(--white);
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  padding: 1.5rem;
}

.card-article:hover {
  transform: translateY(-8px);
  box-shadow: var(--shadow-lg);
  border-color: rgba(45, 106, 79, 0.1);
}

.footer {
  background-color: var(--text-dark);
  color: #94a3b8;
  padding: 4rem 0 2rem;
}

.footer h6 {
  color: var(--white);
  font-weight: 700;
  margin-bottom: 1.5rem;
  text-transform: uppercase;
  font-size: 0.9rem;
  letter-spacing: 1px;
}

.footer a {
  color: #94a3b8;
  text-decoration: none;
  transition: 0.2s;
}

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

.issn-badge {
  font-family: 'JetBrains Mono', monospace;
  background: rgba(45, 106, 79, 0.05);
  color: var(--primary-dark);
  display: inline-block;
  padding: 0.3rem 1rem;
  border-radius: var(--radius-full);
  font-size: 0.8rem;
  font-weight: 600;
}

.text-gradient {
  background: linear-gradient(135deg, var(--primary-dark), var(--primary-color));
  background-clip: text;
  -webkit-background-clip: text;
  color: transparent;
}

.issue-card {
  background: var(--white);
  border-radius: var(--radius-md);
  border: 1px solid rgba(0,0,0,0.05);
  overflow: hidden;
  transition: all 0.3s ease;
}

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

.issue-header {
  background: linear-gradient(to right, #f8fafc, #ffffff);
  border-bottom: 1px solid rgba(0,0,0,0.05);
  padding: 1.5rem;
}

.volume-year {
  font-weight: 800;
  font-size: 1.25rem;
  color: var(--primary-color);
}

.article-item {
  padding: 1.25rem;
  border-bottom: 1px solid rgba(0,0,0,0.03);
  transition: all 0.2s ease;
}

.article-item:last-child {
  border-bottom: none;
}

.article-item:hover {
  background-color: rgba(45, 106, 79, 0.02);
}

.article-title {
  font-weight: 700;
  font-size: 1.1rem;
  color: var(--text-dark);
  margin-bottom: 0.5rem;
  line-height: 1.4;
}

.authors-list {
  font-size: 0.9rem;
  color: var(--text-muted);
  font-style: italic;
}

.pagination-custom .page-link {
  color: var(--primary-color);
  border: none;
  background: var(--white);
  margin: 0 4px;
  border-radius: var(--radius-sm);
  font-weight: 600;
  transition: 0.2s;
}

.pagination-custom .page-item.active .page-link {
  background-color: var(--primary-color);
  color: var(--white);
}

.icon {
  width: 32px;
  height: 32px;
  object-fit: contain;
}

.icon-lx {
  width: 80px;
  height: 80px;
  object-fit: contain;
  margin-bottom: 1.5rem;
}

@media (max-width: 768px) {
  .hero-section {
    padding: 4rem 0 2rem;
    text-align: center;
  }

  .btn-primary-custom, .btn-outline-custom {
    width: 100%;
    margin-bottom: 1rem;
  }
}