/* =========================
   Theme variables
========================= */
:root {
  --bg: #f7f7f7;
  --bg-elevated: #ffffff;
  --text: #222;
  --muted: #666;
  --border: #e0e0e0;
  --accent: #0077cc;
  --accent-hover: #005fa3;
}

/* Dark mode */
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0e0f13;
    --bg-elevated: #171922;
    --text: #e6e6eb;
    --muted: #9aa0aa;
    --border: #2a2d3a;
    --accent: #4da3ff;
    --accent-hover: #1f7ae0;
  }
}

/* =========================
   Reset & base styles
========================= */
* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI",
               Roboto, Helvetica, Arial, sans-serif;
  line-height: 1.6;
  color: var(--text);
  background: linear-gradient(
    120deg,
    var(--bg),
    color-mix(in srgb, var(--bg) 80%, var(--accent))
  );
  background-size: 300% 300%;
  animation: bg-shift 20s ease infinite;
}

/* Animated background */
@keyframes bg-shift {
  0% { background-position: 0% 50%; }
  50% { background-position: 100% 50%; }
  100% { background-position: 0% 50%; }
}

/* =========================
   Layout container
========================= */
.container {
  max-width: 1000px;
  margin: 0 auto;
  padding: 1rem;
}

/* =========================
   Header
========================= */
header {
  background: var(--bg-elevated);
  border-bottom: 1px solid var(--border);
  backdrop-filter: blur(6px);
}

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

header strong {
  font-size: 1.25rem;
}

header nav a {
  text-decoration: none;
  color: var(--accent);
  margin-left: 1rem;
}

header nav a:hover {
  text-decoration: underline;
}

/* =========================
   Main content
========================= */
main {
  padding: 2rem 0;
}

h1 {
  margin-top: 0;
}

/* =========================
   Panel
========================= */
.panel {
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  padding: 1rem;
  border-radius: 6px;
  margin-bottom: 2rem;
}

/* =========================
   Grid layout
========================= */
.grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 1.5rem;
}

/* =========================
   Cards
========================= */
.card {
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  padding: 1.25rem;
  border-radius: 6px;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.card:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 20px rgba(0, 0, 0, 0.15);
}

.card h3 {
  margin-top: 0;
}

/* =========================
   Buttons
========================= */
.button {
  display: inline-block;
  margin-top: 0.75rem;
  padding: 0.5rem 1rem;
  background: var(--accent);
  color: #ffffff;
  text-decoration: none;
  border-radius: 4px;
  transition: background 0.2s ease, transform 0.15s ease;
}

.button:hover {
  background: var(--accent-hover);
  transform: translateY(-1px);
}

/* =========================
   Images
========================= */
.grid img {
  width: 100%;
  height: auto;
  display: block;
  border-radius: 4px;
  border: 1px solid var(--border);
}

/* =========================
   Footer
========================= */
footer {
  text-align: center;
  padding: 1.5rem 1rem;
  font-size: 0.9rem;
  color: var(--muted);
}