/* shared.css — extracted from "how to actually center a div/style.css" + extensions for full course */
* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  max-width: 720px;
  margin: 0 auto;
  padding: 32px 16px 64px;
  font-family: Georgia, 'Times New Roman', serif;
  font-size: 16px;
  line-height: 1.6;
  color: #111;
  background: #fff;
}

h1, h2, h3, h4 {
  font-family: -apple-system, Helvetica, Arial, sans-serif;
  line-height: 1.25;
  color: #000;
}

h1 { font-size: 32px; margin: 0 0 8px; }
h2 { font-size: 20px; margin: 28px 0 8px; border-bottom: 1px solid #ddd; padding-bottom: 6px; }
h3 { font-size: 14px; margin: 20px 0 8px; text-transform: uppercase; letter-spacing: 0.04em; color: #555; }
h4 { font-size: 15px; margin: 16px 0 6px; color: #222; }

hr {
  border: none;
  border-top: 1px solid #ddd;
  margin: 32px 0;
}

p, li { overflow-wrap: break-word; }

a { color: #0b57d0; text-decoration: underline; text-underline-offset: 2px; }
a:hover { color: #052e6e; }
a:visited { color: #5b21b6; }

nav ol, nav ul {
  padding-left: 20px;
}
nav li { margin: 2px 0; font-family: -apple-system, Helvetica, Arial, sans-serif; font-size: 14px; }

pre {
  background: #f4f4f4;
  border: 1px solid #ddd;
  padding: 12px 14px;
  overflow-x: auto;
  font-size: 13px;
  line-height: 1.5;
}

code {
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 0.9em;
  background: #f4f4f4;
  padding: 1px 4px;
  border-radius: 3px;
}
pre code { font-size: 13px; background: none; padding: 0; border-radius: 0; }

table {
  width: 100%;
  border-collapse: collapse;
  font-family: -apple-system, Helvetica, Arial, sans-serif;
  font-size: 13px;
  margin: 16px 0;
}

th, td {
  text-align: left;
  padding: 8px 10px;
  border: 1px solid #ddd;
  vertical-align: top;
}

th {
  background: #f4f4f4;
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

details {
  border: 1px solid #ddd;
  border-radius: 6px;
  padding: 10px 14px;
  margin: 12px 0;
  background: #fafafa;
  font-family: -apple-system, Helvetica, Arial, sans-serif;
  font-size: 14px;
}
details summary { cursor: pointer; font-weight: 600; }
details[open] summary { margin-bottom: 8px; }

kbd {
  font-family: ui-monospace, monospace;
  font-size: 12px;
  border: 1px solid #bbb;
  border-bottom-width: 2px;
  padding: 2px 6px;
  border-radius: 4px;
  background: #f9f9f9;
}

blockquote {
  margin: 12px 0;
  padding: 8px 14px;
  border-left: 3px solid #ddd;
  color: #444;
  background: #fafafa;
  font-size: 14px;
}

footer { margin-top: 32px; }
.course-footer { font-family: -apple-system, Helvetica, Arial, sans-serif; font-size: 13px; color: #666; }

/* — Demos — */
.demo {
  border: 1px solid #bbb;
  background: #fafafa;
  min-height: 80px;
  position: relative;
  overflow: hidden;
  margin: 8px 0 8px;
  padding: 8px;
}
.demo.tall { height: 160px; }
.demo .box {
  background: #fff;
  border: 1px solid #111;
  padding: 8px 14px;
  font-family: -apple-system, Helvetica, Arial, sans-serif;
  font-size: 13px;
  text-align: center;
}
.demo .box.fixed {
  width: 120px;
  height: 80px;
  display: grid;
  place-items: center;
}
.demo .box.fixed-width { width: 140px; }
.demo .box.inline { display: inline-block; margin: 2px; padding: 6px 12px; }
.demo-label {
  font-family: -apple-system, Helvetica, Arial, sans-serif;
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: #777;
  margin: 12px 0 4px;
}

/* badges */
.badge {
  display: inline-block;
  font-family: -apple-system, Helvetica, Arial, sans-serif;
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  padding: 2px 6px;
  border-radius: 4px;
  border: 1px solid #ddd;
  background: #f4f4f4;
  color: #444;
  vertical-align: middle;
  margin-left: 6px;
}
.badge.prereq { background: #fff7cc; border-color: #e6d56c; color: #665500; }
.badge.new { background: #daf5df; border-color: #8fd19b; color: #14522a; }

/* callouts */
.callout {
  border: 1px solid #ddd;
  border-radius: 8px;
  padding: 12px 14px;
  margin: 14px 0;
  font-family: -apple-system, Helvetica, Arial, sans-serif;
  font-size: 14px;
  line-height: 1.5;
}
.callout.gotcha { background: #fff8e1; border-color: #f0d27a; }
.callout.why { background: #eef6ff; border-color: #a8c7f0; }
.callout.exercise { background: #eefaf0; border-color: #a8d8b0; }
.callout strong { font-size: 13px; letter-spacing: 0.02em; }

/* nav breadcrumb */
.breadcrumb { font-family: -apple-system, Helvetica, Arial, sans-serif; font-size: 13px; color: #666; margin-bottom: 12px; }
.breadcrumb a { color: #666; }
.breadcrumb a:hover { color: #111; }

/* module nav prev/next */
.module-nav {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  margin-top: 28px;
  font-family: -apple-system, Helvetica, Arial, sans-serif;
  font-size: 14px;
}
.module-nav a {
  border: 1px solid #ddd;
  padding: 8px 12px;
  border-radius: 6px;
  text-decoration: none;
  background: #fafafa;
  flex: 1;
}
.module-nav a:hover { background: #f0f0f0; border-color: #bbb; }
.module-nav a span { display: block; font-size: 11px; text-transform: uppercase; letter-spacing: 0.05em; color: #777; }

/* landing grid */
.module-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(220px, 1fr)); gap: 12px; margin: 16px 0; }
.module-card {
  border: 1px solid #ddd;
  border-radius: 8px;
  padding: 12px 14px;
  background: #fff;
  text-decoration: none;
  color: inherit;
  display: block;
}
.module-card:hover { border-color: #999; background: #fafafa; }
.module-card h3 { margin: 0 0 4px; font-size: 14px; color: #000; text-transform: none; letter-spacing: 0; }
.module-card p { margin: 0; font-family: -apple-system, Helvetica, Arial, sans-serif; font-size: 12px; color: #666; line-height: 1.4; }
.module-card .num { font-family: ui-monospace, monospace; font-size: 11px; color: #888; }
.phase-label { font-family: -apple-system, Helvetica, Arial, sans-serif; font-size: 12px; font-weight: 700; text-transform: uppercase; letter-spacing: 0.08em; color: #888; margin: 28px 0 10px; border-bottom: 1px solid #eee; padding-bottom: 6px; }

/* inline demo helpers */
.inline-demo { font-family: -apple-system, Helvetica, Arial, sans-serif; font-size: 13px; }