:root {
  --nix-red: #e40303;
  --nix-orange: #ff8c00;
  --nix-yellow: #ffed00;
  --nix-green: #008026;
  --nix-blue: #24408e;
  --nix-purple: #732982;

  --bg: #f8f8fa;
  --bg-tile: #ffffff;
  --text: #1a1a2e;
  --text-secondary: #555;
  --border: #e0e0e0;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0d1117;
    --bg-tile: #161b22;
    --text: #e8e8f0;
    --text-secondary: #a0a0b8;
    --border: #30363d;
  }
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
  padding: 2rem 1.5rem;
  max-width: 960px;
  margin: 0 auto;
}

/* Header */
header {
  text-align: center;
  margin-bottom: 2.5rem;
  padding-bottom: 2rem;
  position: relative;
}

header::after {
  content: "";
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  height: 4px;
  border-radius: 2px;
  background: linear-gradient(
    to right,
    var(--nix-red),
    var(--nix-orange),
    var(--nix-yellow),
    var(--nix-green),
    var(--nix-blue),
    var(--nix-purple)
  );
}

.logo-area {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.8rem;
  margin-bottom: 0.5rem;
}

.logo-area svg {
  flex-shrink: 0;
}

header h1 {
  font-size: 2.4rem;
  letter-spacing: -0.02em;
  line-height: 1;
}

.wordmark-extra {
  font-weight: 300;
}

.wordmark-nix {
  font-weight: 800;
}

header .tagline {
  color: var(--text-secondary);
  font-size: 1.05rem;
  margin-top: 0.4rem;
}

/* Tile grid */
.tiles {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.2rem;
  margin-bottom: 2.5rem;
}

@media (max-width: 768px) {
  .tiles {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 480px) {
  .tiles {
    grid-template-columns: 1fr;
  }
}

/* Tiles */
.tile {
  display: flex;
  flex-direction: column;
  padding: 2rem;
  background: color-mix(in srgb, var(--tile-color) 8%, var(--bg-tile));
  border: 1px solid var(--border);
  border-radius: 12px;
  text-decoration: none;
  color: var(--text);
  transition: transform 0.15s ease, box-shadow 0.15s ease;
  border-top: 4px solid var(--tile-color);
  position: relative;
}

.tile:hover {
  transform: translateY(-3px);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.1);
  background: color-mix(in srgb, var(--tile-color) 14%, var(--bg-tile));
}

@media (prefers-color-scheme: dark) {
  .tile:hover {
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.4);
  }
}

.tile .short {
  font-size: 1.8rem;
  font-weight: 800;
  letter-spacing: -0.01em;
  margin-bottom: 0.4rem;
  color: var(--tile-color);
}

.tile .description {
  font-size: 0.85rem;
  color: var(--text-secondary);
  line-height: 1.4;
  flex-grow: 1;
}

.tile::after {
  content: "\2192";
  display: block;
  margin-top: 1rem;
  font-size: 1.2rem;
  color: var(--tile-color);
  opacity: 0.6;
  transition: opacity 0.15s ease, transform 0.15s ease;
}

.tile:hover::after {
  opacity: 1;
  transform: translateX(4px);
}

/* NixOS rainbow colors by tile position */
.tile:nth-child(6n+1) { --tile-color: var(--nix-red); }
.tile:nth-child(6n+2) { --tile-color: var(--nix-orange); }
.tile:nth-child(6n+3) { --tile-color: var(--nix-yellow); }
.tile:nth-child(6n+4) { --tile-color: var(--nix-green); }
.tile:nth-child(6n+5) { --tile-color: var(--nix-blue); }
.tile:nth-child(6n+6) { --tile-color: var(--nix-purple); }

/* Footer */
footer {
  text-align: center;
  color: var(--text-secondary);
  font-size: 0.85rem;
  line-height: 1.5;
  padding-top: 1rem;
  border-top: 1px solid var(--border);
}