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

body {
  margin: 0;
  font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  background: #050816;
  color: #e5e7eb;
}

a {
  color: #38bdf8;
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

.container {
  max-width: 960px;
  margin: 0 auto;
  padding: 0 1.25rem;
}

.container:has(.page-with-sidebar) {
  max-width: 1240px;
}

.page-with-sidebar {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 280px;
  gap: 2rem;
  align-items: start;
}

.page-with-sidebar .main-content {
  min-width: 0;
}

.sidebar {
  position: sticky;
  top: 1.5rem;
  background: rgba(15, 23, 42, 0.85);
  border: 1px solid rgba(148, 163, 184, 0.25);
  border-radius: 1rem;
  padding: 1.25rem;
}

.sidebar-title {
  margin: 0 0 1rem;
  font-size: 1.1rem;
  color: #e5e7eb;
}

.sidebar-external-links {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.sidebar-external-link {
  display: block;
  padding: 0.75rem;
  border-radius: 0.5rem;
  background: rgba(15, 23, 42, 0.6);
  border: 1px solid rgba(148, 163, 184, 0.2);
  color: inherit;
  text-decoration: none;
  transition: border-color 0.2s, background 0.2s;
}

.sidebar-external-link:hover {
  border-color: rgba(56, 189, 248, 0.5);
  background: rgba(15, 23, 42, 0.9);
  text-decoration: none;
}

.sidebar-external-link-title {
  display: block;
  font-weight: 600;
  font-size: 0.95rem;
  color: #f1f5f9;
  margin-bottom: 0.25rem;
}

.sidebar-external-link-description {
  display: block;
  font-size: 0.8rem;
  line-height: 1.4;
  color: #94a3b8;
}

@media (max-width: 768px) {
  .page-with-sidebar {
    grid-template-columns: 1fr;
  }

  .sidebar {
    position: static;
  }
}

.header {
  background: radial-gradient(circle at top left, #22d3ee, #0f172a);
  color: #f9fafb;
  padding: 1.25rem 0;
  box-shadow: 0 4px 12px rgba(15, 23, 42, 0.6);
}

.logo a {
  color: inherit;
  font-size: 1.35rem;
  font-weight: 700;
}

.main {
  padding: 2.5rem 0 3rem;
}

.card {
  background: radial-gradient(circle at top left, rgba(56, 189, 248, 0.18), rgba(15, 23, 42, 0.98));
  border-radius: 1rem;
  padding: 2rem;
  box-shadow: 0 18px 40px rgba(15, 23, 42, 0.9);
  border: 1px solid rgba(148, 163, 184, 0.3);
}

.card h2 {
  margin-top: 0;
  margin-bottom: 0.75rem;
  font-size: 1.5rem;
}

.card p {
  margin-top: 0.5rem;
  line-height: 1.6;
}

.form {
  margin-top: 1.5rem;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.form label {
  font-size: 0.9rem;
  color: #cbd5f5;
}

.form input[type='text'] {
  padding: 0.65rem 0.75rem;
  border-radius: 0.5rem;
  border: 1px solid rgba(148, 163, 184, 0.6);
  background: rgba(15, 23, 42, 0.8);
  color: #f9fafb;
  outline: none;
}

.form input[type='text']:focus {
  border-color: #38bdf8;
  box-shadow: 0 0 0 1px rgba(56, 189, 248, 0.6);
}

.form button {
  margin-top: 0.5rem;
  padding: 0.75rem 1rem;
  border-radius: 999px;
  border: none;
  background: linear-gradient(135deg, #38bdf8, #8b5cf6);
  color: #f9fafb;
  font-weight: 600;
  cursor: pointer;
  box-shadow: 0 12px 25px rgba(56, 189, 248, 0.35);
}

.form button:hover {
  filter: brightness(1.05);
}

.alert {
  padding: 0.75rem 1rem;
  border-radius: 0.5rem;
  font-size: 0.9rem;
  margin-bottom: 0.75rem;
}

.alert-error {
  background: rgba(248, 113, 113, 0.15);
  border: 1px solid rgba(248, 113, 113, 0.6);
  color: #fecaca;
}

.article-content h1,
.article-content h2,
.article-content h3 {
  color: #e5e7eb;
}

.article-content p {
  line-height: 1.7;
  margin-bottom: 0.75rem;
}

.article-content ul {
  padding-left: 1.25rem;
}

.article-content li {
  margin-bottom: 0.4rem;
}

.meta {
  font-size: 0.85rem;
  color: #9ca3af;
}

.article-figure {
  margin: 0 0 1.5rem;
  border-radius: 0.75rem;
  overflow: hidden;
  border: 1px solid rgba(148, 163, 184, 0.2);
}

.article-image {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
  vertical-align: middle;
}

.link-back {
  display: inline-block;
  margin-top: 1rem;
}

.previews-section {
  margin-top: 2.5rem;
  padding-top: 1.5rem;
  border-top: 1px solid rgba(148, 163, 184, 0.25);
}

.previews-title {
  margin-bottom: 1.25rem;
  font-size: 1.25rem;
  color: #e5e7eb;
}

.previews-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 1rem;
}

.preview-card {
  display: block;
  padding: 1rem;
  border-radius: 0.75rem;
  background: rgba(15, 23, 42, 0.6);
  border: 1px solid rgba(148, 163, 184, 0.2);
  color: inherit;
  transition: border-color 0.2s, background 0.2s;
}

.preview-card:hover {
  border-color: rgba(56, 189, 248, 0.5);
  background: rgba(15, 23, 42, 0.8);
  text-decoration: none;
}

.preview-card-image {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 400 / 210;
  object-fit: cover;
  border-radius: 0.5rem;
  margin-bottom: 0.75rem;
}

.preview-card-title {
  margin: 0 0 0.35rem;
  font-size: 1rem;
  font-weight: 600;
  color: #f1f5f9;
}

.preview-card-subtitle {
  margin: 0;
  font-size: 0.85rem;
  line-height: 1.4;
  color: #94a3b8;
}

.footer {
  padding: 1.5rem 0 2rem;
  border-top: 1px solid rgba(31, 41, 55, 0.9);
  font-size: 0.85rem;
  color: #9ca3af;
}