/* W3C-inspired clean styles */
:root {
  --w3c-blue: #005A9C;
  --text: #1a1a1a;
  --muted-text: #495057;
  --bg: #f5f7f9;
  --card-bg: #ffffff;
  --border: #e1e5ea;
  --link: #0b6efd;
  --focus: #ffbf47;
}

* { box-sizing: border-box; }
html, body { height: 100%; }
body {
  margin: 0;
  font-family: system-ui, -apple-system, Segoe UI, Roboto, Ubuntu, Cantarell, Noto Sans, Helvetica, Arial, "Apple Color Emoji", "Segoe UI Emoji";
  color: var(--text);
  background: var(--bg);
  line-height: 1.6;
}

.wrap {
  max-width: 980px;
  margin: 0 auto;
  padding: 0 16px;
}

/* Header */
.site-header {
  background: var(--w3c-blue);
  color: #fff;
  position: sticky;
  top: 0;
  z-index: 10;
  box-shadow: 0 2px 6px rgba(0,0,0,0.1);
}
.site-header .wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 16px;
}
.brand {
  font-weight: 700;
  letter-spacing: 0.2px;
}
.site-nav a {
  color: #cfe6ff;
  text-decoration: none;
  margin-left: 16px;
  padding: 6px 8px;
  border-radius: 4px;
}
.site-nav a:hover,
.site-nav a:focus {
  color: #fff;
  background: rgba(255,255,255,0.15);
  outline: none;
}

/* Main */
.site-main {
  padding: 24px 16px 48px;
}
.site-main h1 {
  margin-top: 12px;
  font-size: 2rem;
}

.card {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 16px;
  margin: 16px 0;
  box-shadow: 0 1px 2px rgba(0,0,0,0.03);
}

/* Buttons */
.btn {
  display: inline-block;
  padding: 10px 14px;
  border-radius: 6px;
  border: 1px solid #0a58ca;
  background: #0b6efd;
  color: #fff;
  font-weight: 600;
  cursor: pointer;
}
.btn:hover,
.btn:focus {
  background: #0a58ca;
  border-color: #0a58ca;
}
.btn:focus {
  outline: 3px solid var(--focus);
  outline-offset: 2px;
}

/* Footer */
.site-footer {
  border-top: 1px solid var(--border);
  background: #fff;
}
.site-footer .wrap {
  padding: 16px;
  color: var(--muted-text);
}

/* Elements */
code {
  background: #f1f3f5;
  border: 1px solid #e9ecef;
  padding: 2px 6px;
  border-radius: 4px;
  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace;
  font-size: 0.95em;
}

@media (max-width: 480px) {
  .site-nav a { margin-left: 8px; }
  .site-main { padding: 16px 8px 32px; }
}