/* ============================================================
   GET IN THE GITHUB WORKFLOW — lesson.css
   Dark mode, GitHub Primer palette
   ============================================================ */

@import url('https://fonts.googleapis.com/css2?family=JetBrains+Mono:wght@400;500;700&family=Inter:wght@400;500;600;700&display=swap');

:root {
  --bg-base:        #0d1117;
  --bg-elevated:    #161b22;
  --bg-subtle:      #21262d;
  --bg-overlay:     #2d333b;
  --border:         #30363d;

  --text-primary:   #e6edf3;
  --text-secondary: #8b949e;
  --text-muted:     #6e7681;

  --green:          #0FBF3E;
  --green-muted:    rgba(15, 191, 62, 0.12);
  --green-border:   rgba(15, 191, 62, 0.3);
  --purple:         #8534F3;
  --purple-muted:   rgba(133, 52, 243, 0.12);
  --purple-border:  rgba(133, 52, 243, 0.3);

  --danger:         #f85149;
  --danger-muted:   rgba(248, 81, 73, 0.12);
  --warning:        #e3b341;

  --font-body: 'Inter', system-ui, sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', monospace;

  --max-width: 720px;
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  background: var(--bg-base);
  color: var(--text-primary);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.7;
}
a { color: var(--green); text-decoration: none; }
a:hover { text-decoration: underline; }

/* ── Progress Bar ── */
#progress-bar-wrap {
  position: sticky; top: 0; z-index: 100;
  background: var(--bg-elevated);
  border-bottom: 1px solid var(--border);
  padding: 10px 20px;
  display: flex; align-items: center; gap: 12px;
}
#progress-bar-track {
  flex: 1; height: 6px;
  background: var(--bg-subtle);
  border-radius: 99px; overflow: hidden;
}
#progress-bar-fill {
  height: 100%; width: 0%;
  background: linear-gradient(90deg, var(--green), var(--purple));
  border-radius: 99px;
  transition: width 0.2s ease;
}
#progress-label {
  font-size: 12px; font-family: var(--font-mono);
  color: var(--text-secondary);
  white-space: nowrap; min-width: 80px; text-align: right;
}

/* ── Page Header ── */
.page-header {
  background: var(--bg-elevated);
  border-bottom: 1px solid var(--border);
  padding: 48px 24px 40px;
  text-align: center;
}
.page-header .octocat { font-size: 52px; margin-bottom: 16px; display: block; }
.page-header h1 {
  font-size: clamp(1.8rem, 4vw, 2.6rem);
  font-weight: 700; letter-spacing: -0.02em; line-height: 1.2;
  margin-bottom: 12px;
}
.accent-green { color: var(--green); }
.accent-purple { color: var(--purple); }
.page-header .subtitle {
  color: var(--text-secondary); font-size: 1rem;
  max-width: 520px; margin: 0 auto 24px;
}
.reset-btn {
  background: transparent; border: 1px solid var(--border);
  color: var(--text-muted); font-family: var(--font-mono);
  font-size: 12px; padding: 6px 14px; border-radius: var(--radius-sm);
  cursor: pointer; transition: all 0.15s;
}
.reset-btn:hover { border-color: var(--danger); color: var(--danger); }

/* ── Layout ── */
.lesson-body {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 40px 20px 80px;
}

/* ── Step Sections ── */
.step-section { margin-bottom: 48px; transition: opacity 0.3s, filter 0.3s; }
.step-section.locked { opacity: 0.3; filter: blur(1.5px); pointer-events: none; user-select: none; }

.section-header {
  display: flex; align-items: center; gap: 12px;
  margin-bottom: 20px; padding-bottom: 12px;
  border-bottom: 1px solid var(--border);
}
.section-number {
  display: flex; align-items: center; justify-content: center;
  width: 32px; height: 32px; border-radius: 50%;
  background: var(--purple-muted); border: 1px solid var(--purple-border);
  color: var(--purple); font-family: var(--font-mono);
  font-size: 13px; font-weight: 700; flex-shrink: 0;
}
.section-header h2 { font-size: 1.25rem; font-weight: 600; letter-spacing: -0.01em; }

/* ── Floating Tooltip ── */
#floating-tooltip {
  position: fixed; z-index: 999;
  background: var(--bg-overlay);
  border: 1px solid var(--purple-border);
  border-radius: var(--radius-md);
  padding: 10px 14px; font-size: 13px;
  max-width: 280px; line-height: 1.5;
  color: var(--text-primary);
  box-shadow: 0 8px 24px rgba(0,0,0,0.5);
  pointer-events: none; opacity: 0; transition: opacity 0.15s;
}
#floating-tooltip.visible { opacity: 1; }
.term { color: var(--purple); border-bottom: 1px dashed var(--purple-border); cursor: help; }
.term:hover { color: #a66fff; }
.term .term-tooltip { display: none; }

/* ── Accordions ── */
.accordion {
  border: 1px solid var(--border); border-radius: var(--radius-md);
  margin-bottom: 12px; overflow: hidden;
}
.accordion-btn {
  width: 100%; background: var(--bg-elevated); border: none;
  color: var(--text-primary); font-family: var(--font-body);
  font-size: 14px; font-weight: 500;
  padding: 14px 18px;
  display: flex; justify-content: space-between; align-items: center;
  cursor: pointer; text-align: left; transition: background 0.15s;
}
.accordion-btn:hover { background: var(--bg-subtle); }
.chevron { font-size: 11px; color: var(--text-muted); transition: transform 0.2s; flex-shrink: 0; }
.accordion-btn.open .chevron { transform: rotate(180deg); }
.accordion-body { max-height: 0; overflow: hidden; transition: max-height 0.35s ease; }
.accordion-body.open { max-height: 2000px; }
.accordion-inner {
  padding: 16px 18px; border-top: 1px solid var(--border);
  font-size: 14px; color: var(--text-secondary); line-height: 1.7;
}
.accordion-inner p { margin-bottom: 10px; }
.accordion-inner p:last-child { margin-bottom: 0; }

/* ── Code Blocks ── */
.code-block {
  background: var(--bg-subtle); border: 1px solid var(--border);
  border-radius: var(--radius-md); overflow: hidden; margin: 14px 0;
  font-family: var(--font-mono);
}
.code-block-header {
  display: flex; justify-content: space-between; align-items: center;
  padding: 7px 14px; background: var(--bg-overlay);
  border-bottom: 1px solid var(--border);
  font-size: 12px; color: var(--text-muted);
}
.code-block pre {
  padding: 14px 16px; font-size: 13.5px; line-height: 1.65;
  overflow-x: auto; color: var(--green);
  white-space: pre; word-break: normal;
}

/* ── Quiz ── */
.quiz-block {
  background: var(--bg-elevated); border: 1px solid var(--purple-border);
  border-radius: var(--radius-lg); padding: 22px; margin: 24px 0;
}
.quiz-block h4 {
  color: var(--purple); font-size: 12px; font-family: var(--font-mono);
  text-transform: uppercase; letter-spacing: 0.1em; margin-bottom: 10px;
}
.quiz-question { font-size: 15px; font-weight: 500; margin-bottom: 14px; color: var(--text-primary); }
.quiz-options { list-style: none; display: flex; flex-direction: column; gap: 8px; }
.quiz-options button {
  width: 100%; background: var(--bg-subtle); border: 1px solid var(--border);
  color: var(--text-primary); font-family: var(--font-body); font-size: 14px;
  padding: 11px 16px; border-radius: var(--radius-md);
  cursor: pointer; text-align: left; transition: all 0.15s;
}
.quiz-options button:hover:not(:disabled) { border-color: var(--purple-border); background: var(--purple-muted); }
.quiz-options button.correct { border-color: var(--green); background: var(--green-muted); color: var(--green); }
.quiz-options button.wrong { border-color: var(--danger); background: var(--danger-muted); color: var(--danger); opacity: 0.5; }
.quiz-options button:disabled { cursor: not-allowed; }
.quiz-feedback {
  margin-top: 12px; font-size: 13px;
  color: var(--text-secondary); font-style: italic; min-height: 20px;
}
.quiz-feedback.correct { color: var(--green); font-style: normal; font-weight: 500; }
.quiz-feedback.wrong { color: var(--danger); font-style: normal; }

/* ── Checklists ── */
.checklist { list-style: none; display: flex; flex-direction: column; gap: 8px; margin: 14px 0; }
.checklist li {
  display: flex; align-items: flex-start; gap: 12px;
  padding: 10px 14px; background: var(--bg-elevated);
  border: 1px solid var(--border); border-radius: var(--radius-md);
  cursor: pointer; transition: all 0.15s; font-size: 14px; color: var(--text-secondary);
}
.checklist li:hover { border-color: var(--green-border); }
.checklist li.checked {
  color: var(--text-muted); text-decoration: line-through;
  border-color: var(--green-border); background: var(--green-muted);
}
.check-icon { color: var(--border); font-weight: 700; flex-shrink: 0; transition: color 0.15s; }
.checklist li.checked .check-icon { color: var(--green); }

/* ── Callouts ── */
.callout {
  display: flex; gap: 12px; padding: 14px 16px;
  border-radius: var(--radius-md); border-left: 3px solid;
  margin: 14px 0; font-size: 14px; line-height: 1.6;
}
.callout-icon { font-size: 16px; flex-shrink: 0; margin-top: 1px; }
.callout.tip    { background: var(--purple-muted); border-color: var(--purple); color: var(--text-secondary); }
.callout.note   { background: rgba(59,130,246,0.08); border-color: #3b82f6; color: var(--text-secondary); }
.callout.warning { background: rgba(227,179,65,0.08); border-color: var(--warning); color: var(--text-secondary); }
.callout.success { background: var(--green-muted); border-color: var(--green); color: var(--text-secondary); }

/* ── Practice Box ── */
.practice-box {
  background: var(--bg-elevated); border: 1px solid var(--green-border);
  border-radius: var(--radius-lg); padding: 20px 22px; margin: 22px 0;
}
.practice-box h4 {
  color: var(--green); font-size: 12px; font-family: var(--font-mono);
  text-transform: uppercase; letter-spacing: 0.1em; margin-bottom: 10px;
}
.practice-box > p { font-size: 14px; color: var(--text-secondary); margin-bottom: 8px; }
.practice-box > p:last-child { margin-bottom: 0; }

/* ── Tables ── */
.lesson-table { width: 100%; border-collapse: collapse; margin: 14px 0; font-size: 14px; }
.lesson-table th {
  background: var(--bg-overlay); color: var(--text-secondary);
  font-weight: 600; font-size: 12px; text-transform: uppercase;
  letter-spacing: 0.05em; padding: 9px 14px;
  border: 1px solid var(--border); text-align: left;
}
.lesson-table td {
  padding: 9px 14px; border: 1px solid var(--border);
  color: var(--text-secondary); vertical-align: top;
}
.lesson-table tr:nth-child(even) td { background: var(--bg-elevated); }
.lesson-table td code, .lesson-table th code { font-size: 12px; }

/* ── Images ── */
.lesson-img {
  width: 100%; border-radius: var(--radius-md);
  max-width: 500px;
  border: 1px solid var(--border); margin: 14px 0; display: block; margin: auto;
}
.lesson-img-caption {
  font-size: 12px; color: var(--text-muted);
  font-family: var(--font-mono); text-align: center;
  margin-top: 8px; margin-bottom: 14px;
}

/* ── Inline Typography ── */
.lesson-body p { margin-bottom: 12px; color: var(--text-secondary); }
.lesson-body h3 { font-size: 1rem; font-weight: 600; color: var(--text-primary); margin: 22px 0 8px; }
.lesson-body ul, .lesson-body ol { padding-left: 20px; margin-bottom: 12px; color: var(--text-secondary); }
.lesson-body li { margin-bottom: 5px; }
code {
  font-family: var(--font-mono); font-size: 0.875em;
  background: var(--bg-subtle); border: 1px solid var(--border);
  border-radius: 3px; padding: 1px 6px; color: var(--green);
}
strong { color: var(--text-primary); font-weight: 600; }
em { font-style: italic; color: var(--text-secondary); }
hr { border: none; border-top: 1px solid var(--border); margin: 36px 0; }

/* ── Resource Cards ── */
.resource-grid {
  display: grid; grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 12px; margin: 14px 0;
}
.resource-card {
  background: var(--bg-elevated); border: 1px solid var(--border);
  border-radius: var(--radius-md); padding: 16px; transition: border-color 0.15s;
}
.resource-card:hover { border-color: var(--purple-border); }
.resource-card h4 { font-size: 14px; font-weight: 600; margin-bottom: 6px; color: var(--text-primary); }
.resource-card p { font-size: 13px; color: var(--text-muted); margin: 0; line-height: 1.5; }
.resource-card a { display: inline-block; margin-top: 8px; font-size: 12px; font-family: var(--font-mono); color: var(--purple); }

/* ── File Explorer ── */
#file-explorer-section {
  background: var(--bg-elevated); border: 1px solid var(--border);
  border-radius: var(--radius-lg); overflow: hidden; margin-bottom: 48px;
}
.fe-header {
  background: var(--bg-overlay); border-bottom: 1px solid var(--border);
  padding: 18px 24px;
}
.fe-header h2 { font-size: 1.15rem; font-weight: 600; margin-bottom: 4px; }
.fe-header p { color: var(--text-secondary); font-size: 14px; margin: 0; }
.fe-body { padding: 20px 24px; }
.fe-narrative {
  font-size: 14px; color: var(--text-secondary);
  margin-bottom: 16px; padding: 12px 14px;
  background: var(--bg-subtle); border-radius: var(--radius-md);
  border-left: 3px solid var(--purple); line-height: 1.6; min-height: 48px;
}
.fe-workspace {
  background: var(--bg-base); border: 1px solid var(--border);
  border-radius: var(--radius-md); padding: 14px;
  min-height: 160px; margin-bottom: 14px;
  font-family: var(--font-mono); font-size: 13px;
}
.fe-folder { min-width: 160px; margin-bottom: 12px; }
.fe-folder-name { color: var(--warning); font-weight: 500; margin-bottom: 4px; }
.fe-folder-new .fe-folder-name { color: var(--danger); }
.fe-folder-solution .fe-folder-name { color: var(--green); }
.fe-folder-tree { list-style: none; padding-left: 16px; }
.fe-folder-tree li { padding: 2px 4px; display: flex; align-items: center; gap: 6px; }
.fe-folder-tree .file         { color: var(--text-secondary); }
.fe-folder-tree .file-new-red { color: var(--danger); font-weight: 500; }
.fe-folder-tree .file-new     { color: var(--green); font-weight: 500; }
.fe-folder-tree .file::before         { content: '├ '; color: var(--border); }
.fe-folder-tree .file-new-red::before { content: '├ '; color: var(--danger); opacity: 0.5; }
.fe-folder-tree .file-new::before     { content: '├ '; color: var(--green); opacity: 0.5; }
.fe-controls { display: flex; align-items: center; gap: 14px; }
.fe-step-label { font-size: 12px; font-family: var(--font-mono); color: var(--text-muted); }
.fe-btn {
  background: var(--bg-overlay); border: 1px solid var(--border);
  color: var(--text-primary); font-family: var(--font-body);
  font-size: 13px; padding: 8px 18px; border-radius: var(--radius-md);
  cursor: pointer; transition: all 0.15s;
}
.fe-btn:hover { border-color: var(--purple-border); color: var(--purple); }
.fe-btn.primary { border-color: var(--green-border); color: var(--green); background: var(--green-muted); }
.fe-btn.primary:hover { background: rgba(15,191,62,0.2); }

/* Side-by-side compare layout for final step */
.fe-compare {
  display: grid; grid-template-columns: 1fr auto 1fr;
  gap: 12px; align-items: start; width: 100%;
}
.fe-compare-col { display: flex; flex-direction: column; gap: 10px; }
.fe-compare-label {
  font-size: 11px; font-family: var(--font-mono);
  text-transform: uppercase; letter-spacing: 0.08em;
  padding: 4px 8px; border-radius: var(--radius-sm); margin-bottom: 4px;
}
.fe-compare-before .fe-compare-label {
  color: var(--danger); background: var(--danger-muted);
  border: 1px solid rgba(248,81,73,0.2);
}
.fe-compare-after .fe-compare-label {
  color: var(--green); background: var(--green-muted);
  border: 1px solid var(--green-border);
}
.fe-compare-divider {
  font-size: 20px; color: var(--text-muted);
  padding-top: 32px; text-align: center;
}

/* ── Scrollbar ── */
::-webkit-scrollbar { width: 6px; height: 6px; }
::-webkit-scrollbar-track { background: var(--bg-base); }
::-webkit-scrollbar-thumb { background: var(--bg-overlay); border-radius: 99px; }

/* ── Responsive ── */
@media (max-width: 640px) {
  .lesson-body { padding: 24px 16px 60px; }
  .page-header { padding: 32px 16px 28px; }
  .resource-grid { grid-template-columns: 1fr; }
  .lesson-table { font-size: 12px; }
  .lesson-table th, .lesson-table td { padding: 7px 10px; }
  .fe-compare { grid-template-columns: 1fr; }
  .fe-compare-divider { padding-top: 0; }
}