/* AI Learning — Shared Design System
   Version: 1.0.0 | 2026-03-26
   Source: https://janrummel.github.io/ai-learning/shared-style.css
   Used by: agent-literacy, github-fuer-nicht-programmierer, obsidian-fuer-einsteiger
   
   Import: <link rel="stylesheet" href="https://janrummel.github.io/ai-learning/shared-style.css">
   Then add course-specific CSS in a local <style> block or local .css file.
*/

/* === Variables === */
:root {
  --bg: #0d1117; --surface: #161b22; --border: #30363d;
  --text: #e6edf3; --muted: #9ca3af; --accent: #58a6ff;
  --green: #3fb950; --orange: #d29922; --purple: #8957e5;
}
@media (prefers-color-scheme: light) {
  :root {
    --bg: #ffffff; --surface: #f6f8fa; --border: #d1d5db;
    --text: #1f2937; --muted: #6b7280; --accent: #2563eb;
    --green: #16a34a; --orange: #d97706; --purple: #7c3aed;
  }
}

/* === Reset === */
*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }
html { overflow-x: hidden; }
body {
  font-family: -apple-system, BlinkMacSystemFont, 'SF Pro', system-ui, sans-serif;
  background: var(--bg); color: var(--text); min-height: 100vh; line-height: 1.7;
  overflow-x: hidden;
}
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }

/* === Skip Link (Accessibility) === */
.skip-link {
  position: absolute; top: -40px; left: 0; padding: 0.5rem 1rem;
  background: var(--accent); color: var(--bg); z-index: 1000;
  font-weight: 600; border-radius: 0 0 8px 0;
}
.skip-link:focus { top: 0; }

/* === Language Switch === */
.lang-switch {
  position: fixed; top: 1rem; right: 1.5rem; z-index: 100;
  display: flex; gap: 0.25rem; background: var(--surface); border: 1px solid var(--border);
  border-radius: 8px; padding: 0.2rem;
}
.lang-btn {
  padding: 0.3rem 0.6rem; border-radius: 6px; border: none;
  background: transparent; color: var(--muted); cursor: pointer;
  font-size: 0.8rem; font-weight: 600; transition: all 0.2s;
}
.lang-btn.active { background: var(--accent); color: var(--bg); }
.lang-btn:hover:not(.active) { color: var(--text); }
[lang="de"] .en, [lang="en"] .de { display: none; }

/* === Layout === */
.container { max-width: 720px; width: 100%; margin: 0 auto; padding: 5rem 2rem 2rem; }

/* === Typography === */
h1 { font-size: 2rem; font-weight: 800; margin-bottom: 0.5rem; }
h2 { font-size: 1.3rem; font-weight: 800; margin: 2.5rem 0 0.75rem; color: var(--accent); }
h3 { font-size: 1.1rem; font-weight: 700; margin: 1.5rem 0 0.5rem; }
.subtitle { color: var(--muted); margin-bottom: 2rem; }

/* === Step Card (shared across courses) === */
.step {
  background: var(--surface); border: 1px solid var(--border); border-radius: 12px;
  padding: 1.5rem; margin-bottom: 1.5rem;
}
.step-header { display: flex; align-items: center; gap: 0.75rem; margin-bottom: 1rem; }
.step-num {
  width: 32px; height: 32px; background: var(--accent); color: var(--bg);
  border-radius: 8px; display: flex; align-items: center; justify-content: center;
  font-weight: 800; font-size: 0.9rem; flex-shrink: 0;
}
.step-title { font-weight: 700; font-size: 1.05rem; }

/* === Callouts === */
.callout {
  border-radius: 12px; padding: 1rem 1.25rem; margin: 1.5rem 0;
  font-size: 0.9rem; line-height: 1.6;
  border-left: 4px solid var(--border); background: var(--surface);
}
.callout.blue { border-left-color: var(--accent); background: rgba(88,166,255,.06); }
.callout.green { border-left-color: var(--green); background: rgba(63,185,80,.06); }
.callout.orange { border-left-color: var(--orange); background: rgba(210,153,34,.06); }
.callout.red { border-left-color: #f85149; background: rgba(248,81,73,.06); }
.callout.purple { border-left-color: var(--purple); background: rgba(137,87,229,.06); }

/* === Back to Top === */
.back-to-top {
  position: fixed; bottom: 2rem; right: 2rem; z-index: 100;
  background: var(--surface); color: var(--accent); border: 1px solid var(--border);
  border-radius: 50%; width: 40px; height: 40px; font-size: 1.2rem;
  cursor: pointer; display: flex; align-items: center; justify-content: center;
  transition: opacity 0.2s, transform 0.2s; opacity: 0.7;
}
.back-to-top:hover { opacity: 1; transform: translateY(-2px); }

/* === Footer === */
.footer {
  text-align: center; padding: 2rem 1rem; margin-top: 3rem;
  border-top: 1px solid var(--border); font-size: 0.75rem; color: var(--muted);
}
.footer a { color: var(--accent); }

/* === Details/Summary === */
details { margin: 0.75rem 0; }
summary {
  cursor: pointer; color: var(--accent); font-size: 0.85rem;
  font-weight: 600; padding: 0.25rem 0;
}
summary:hover { text-decoration: underline; }

/* === Lists === */
ul, ol { padding-left: 1.5rem; margin: 0.5rem 0; }
li { margin-bottom: 0.4rem; }

/* === Responsive === */
@media (max-width: 768px) {
  .lang-switch { top: 0.75rem; right: 1rem; }
  .container { padding: 4rem 1.25rem 2rem; }
}
@media (max-width: 640px) {
  h1 { font-size: 1.8rem; }
  .container { padding: 3.5rem 1rem 1.5rem; }
}