:root {
  --bg-darkest: #021024;
  --bg-dark: #052659;
  --accent-medium: #5483b3;
  --accent-light: #7da0ca;
  --lightest: #c1e8ff;
  --text-primary: #e6f0ff;
  --text-secondary: #a8c0e0;
  --border-subtle: rgba(84, 131, 179, 0.3);
  --shadow: 0 8px 32px rgba(2, 16, 36, 0.5);
  --radius: 16px;
  --transition: all 0.3s ease;
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family:
    "Segoe UI",
    system-ui,
    -apple-system,
    sans-serif;
  background-color: #274066;
  color: var(--text-primary);
  min-height: 100vh;
  line-height: 1.6;
  padding: 2rem 1rem;
}

.container {
  max-width: 900px;
  margin: 0 auto;
}

h1 {
  text-align: center;
  font-size: 2.8rem;
  margin-bottom: 1.5rem;
  color: var(--lightest);
  text-shadow: 0 2px 10px rgba(193, 232, 255, 0.15);
}

h3 {
  color: var(--accent-light);
  margin-bottom: 0.6rem;
  font-size: 1.35rem;
}

#tags {
  text-align: center;
  margin: 2rem 0 3rem;
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 0.9rem;
}

#tags button {
  background: linear-gradient(
    135deg,
    var(--accent-medium),
    var(--accent-light)
  );
  color: white;
  border: none;
  padding: 0.8rem 1.6rem;
  font-size: 1rem;
  border-radius: 50px;
  cursor: pointer;
  transition: var(--transition);
  box-shadow: 0 4px 15px rgba(84, 131, 179, 0.3);
}

#tags button:hover {
  transform: translateY(-3px);
  box-shadow: 0 12px 30px rgba(125, 160, 202, 0.5);
}

#tags button.active,
#tags button:focus {
  background: var(--lightest);
  color: var(--bg-darkest);
  box-shadow: 0 0 20px rgba(193, 232, 255, 0.6);
  outline: none;
}

#resources {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 1.5rem;
}

.resource {
  background: rgba(5, 38, 89, 0.35);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius);
  padding: 1.5rem;
  transition: var(--transition);
  box-shadow: var(--shadow);
}

.resource:hover {
  transform: translateY(-6px);
  box-shadow: 0 16px 40px rgba(2, 16, 36, 0.6);
  border-color: var(--accent-light);
}

.resource a {
  color: var(--accent-light);
  text-decoration: none;
  font-weight: 500;
  transition: var(--transition);
}

.resource a:hover {
  color: var(--lightest);
  text-decoration: underline;
}

.resource p {
  margin: 0.5rem 0;
  color: var(--text-secondary);
  font-size: 0.95rem;
}

.hidden {
  display: none !important;
}

@media (max-width: 600px) {
  h1 {
    font-size: 2.2rem;
  }

  #tags {
    gap: 0.7rem;
  }

  #tags button {
    padding: 0.7rem 1.3rem;
    font-size: 0.95rem;
  }

  #resources {
    grid-template-columns: 1fr;
  }
}

footer {
  text-align: center;
  margin-top: 4rem;
  padding: 2rem 0;
  color: var(--text-secondary);
  font-size: 0.9rem;
  border-top: 1px solid var(--border-subtle);
}