/*
 * Styles for the static /learn pages (plain HTML in client/public/learn/).
 * These pages are served as files by nginx, with no JavaScript, so that search
 * engines and AI crawlers that do not run JS can read them. Colours mirror the
 * tokens in client/src/App.css.
 */
:root {
  --primary: #667eea;
  --primary-dark: #4c51bf;
  --accent: #764ba2;
  --bg: #ffffff;
  --bg-secondary: #f8fafc;
  --text: #1e293b;
  --text-secondary: #64748b;
  --border: #e2e8f0;
  --link: #4c51bf;
  --code-bg: #f1f5f9;
  --note-bg: #eef2ff;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #1e293b;
    --bg-secondary: #0f172a;
    --text: #e2e8f0;
    --text-secondary: #94a3b8;
    --border: #334155;
    --link: #a3bffa;
    --code-bg: #0f172a;
    --note-bg: #273449;
  }
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: var(--bg-secondary);
  color: var(--text);
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Ubuntu, sans-serif;
  font-size: 17px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--link); }
a:hover { text-decoration-thickness: 2px; }

code, pre {
  font-family: 'SF Mono', 'Fira Code', Menlo, Monaco, Consolas, monospace;
  font-size: 0.88em;
}
code { background: var(--code-bg); padding: 0.1em 0.35em; border-radius: 4px; overflow-wrap: anywhere; }
pre {
  background: var(--code-bg);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 14px 16px;
  overflow-x: auto;
  line-height: 1.5;
}
pre code { background: none; padding: 0; }

.learn-header {
  background: linear-gradient(135deg, var(--primary) 0%, var(--accent) 100%);
  color: #fff;
}
.learn-header-inner,
.learn-main,
.learn-footer-inner {
  max-width: 820px;
  margin: 0 auto;
  padding: 0 16px;
}
.learn-header-inner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 8px 20px;
  padding-top: 14px;
  padding-bottom: 14px;
}
.learn-brand {
  color: #fff;
  font-weight: 700;
  font-size: 1.1rem;
  text-decoration: none;
}
.learn-nav { display: flex; flex-wrap: wrap; gap: 4px 16px; font-size: 0.93rem; }
.learn-nav a { color: #fff; text-decoration: none; opacity: 0.9; }
.learn-nav a:hover, .learn-nav a[aria-current="page"] { opacity: 1; text-decoration: underline; }

.learn-main {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 12px;
  margin-top: 28px;
  margin-bottom: 28px;
  padding: 28px 32px 36px;
}
@media (max-width: 640px) {
  .learn-main { margin: 16px 16px; padding: 20px 16px 28px; }
}

h1 { font-size: 2rem; line-height: 1.25; margin: 0 0 0.4em; }
h2 { font-size: 1.4rem; line-height: 1.3; margin: 1.8em 0 0.5em; padding-top: 0.6em; border-top: 1px solid var(--border); }
h3 { font-size: 1.12rem; margin: 1.4em 0 0.4em; }
p, ul, ol { margin: 0 0 1em; }
li { margin-bottom: 0.35em; }

.lede { font-size: 1.12rem; color: var(--text); }
.meta { color: var(--text-secondary); font-size: 0.9rem; margin-bottom: 1.4em; }

.note {
  background: var(--note-bg);
  border-left: 4px solid var(--primary);
  border-radius: 6px;
  padding: 12px 16px;
  margin: 0 0 1.2em;
}
.note p:last-child { margin-bottom: 0; }

.table-wrap { overflow-x: auto; margin: 0 0 1.2em; }
table { border-collapse: collapse; width: 100%; font-size: 0.94rem; }
th, td { border: 1px solid var(--border); padding: 8px 10px; text-align: left; vertical-align: top; }
th { background: var(--bg-secondary); }

dl.facts { display: grid; grid-template-columns: max-content 1fr; gap: 6px 18px; margin: 0 0 1.2em; }
dl.facts dt { font-weight: 600; }
dl.facts dd { margin: 0; overflow-wrap: anywhere; }
@media (max-width: 640px) {
  dl.facts { grid-template-columns: 1fr; gap: 2px; }
  dl.facts dd { margin-bottom: 8px; }
}

.faq h3 { border-top: 1px solid var(--border); padding-top: 1em; }
.faq h2 + h3 { border-top: none; padding-top: 0; }

.next { margin-top: 2.2em; padding-top: 1em; border-top: 1px solid var(--border); }

.learn-footer { color: var(--text-secondary); font-size: 0.88rem; padding-bottom: 32px; }
.learn-footer a { color: var(--text-secondary); }