/* ── Tokens ───────────────────────────────────────── */
:root {
  --blue: #f76900;        /* iSchool primary orange */
  --blue-dark: #d74100;   /* iSchool dark orange (hover) */
  --blue-light: #fff4ec;  /* light orange tint */
  --blue-mid: #ffd4b0;    /* orange mid */
  --navy: #000e54;        /* iSchool dark navy */
  --green: #22c55e;
  --green-light: #dcfce7;
  --red: #ef4444;
  --red-light: #fee2e2;
  --orange-light: #fff7ed;
  --orange: #f59e0b;
  --text: #000e54;        /* iSchool body text */
  --text-muted: #4a5568;
  --text-faint: #9ea0a4;
  --border: #e2e2e2;      /* iSchool border */
  --surface: #f2f3f5;     /* iSchool light gray */
  --white: #ffffff;
  --topbar-h: 48px;
  --sidebar-w: 220px;
  --terminal-bg: #0f172a;
  --terminal-chrome: #1e293b;
  --terminal-border: #334155;
  --terminal-text: #f1f5f9;
  --terminal-muted: #e2e8f0;
  --terminal-faint: #94a3b8;
  --terminal-prompt-label: #93c5fd;
  --terminal-green: #4ade80;
  --terminal-red: #f87171;
  --radius-pill: 999px;
}

/* ── Reset ────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
body { font-family: system-ui, -apple-system, sans-serif; color: var(--text); background: var(--white); font-size: 15px; line-height: 1.6; }
a { color: var(--blue); text-decoration: none; }
a:hover { text-decoration: underline; }
code { font-family: 'Courier New', monospace; font-size: 13px; background: var(--blue-light); padding: 1px 5px; border-radius: 3px; color: var(--blue); }

/* ── OS Overlay ───────────────────────────────────── */
#os-overlay {
  position: fixed; inset: 0; background: rgba(15,23,42,0.6);
  display: flex; align-items: center; justify-content: center; z-index: 1000;
}
.os-overlay-box {
  background: var(--white); border-radius: 12px; padding: 36px 40px;
  max-width: 360px; width: 100%; text-align: center; box-shadow: 0 20px 60px rgba(0,0,0,0.2);
}
.os-overlay-box h2 { font-size: 22px; margin-bottom: 8px; }
.os-overlay-box > p { color: var(--text-muted); margin-bottom: 24px; }
.os-buttons { display: flex; flex-direction: column; gap: 10px; }
.os-btn {
  display: flex; align-items: center; gap: 14px;
  background: var(--surface); border: 2px solid var(--border);
  border-radius: 10px; padding: 12px 16px; cursor: pointer;
  font-size: 14px; text-align: left; transition: border-color .15s, background .15s;
}
.os-btn:hover { border-color: var(--blue); background: var(--blue-light); }
.os-btn .os-icon { font-size: 24px; line-height: 1; }
.os-btn .os-name { font-weight: 600; color: var(--text); }
.os-btn .os-desc { font-size: 12px; color: var(--text-muted); }
.os-note { font-size: 12px; color: var(--text-faint); margin-top: 16px; }

/* ── Top Bar ──────────────────────────────────────── */
.topbar {
  position: sticky; top: 0; z-index: 100;
  height: var(--topbar-h); background: var(--navy);
  display: flex; align-items: center; justify-content: space-between;
  padding: 0 20px;
}
.topbar-brand {
  display: flex; align-items: center; gap: 12px;
  color: var(--white); font-weight: 700; font-size: 15px;
}
.topbar-brand:hover { text-decoration: none; opacity: .9; }
.topbar-logo-img { height: 30px; width: auto; flex-shrink: 0; }
.topbar-divider { width: 1px; height: 22px; background: rgba(255,255,255,.3); flex-shrink: 0; }
.topbar-course { color: var(--white); font-size: 15px; font-weight: 600; }
.topbar-os { display: flex; align-items: center; gap: 10px; font-size: 13px; color: rgba(255,255,255,.7); }
.os-badge {
  background: var(--blue); color: var(--white);
  font-weight: 700; font-size: 12px; padding: 3px 12px; border-radius: var(--radius-pill);
}
.change-os {
  background: transparent; border: 1px solid rgba(255,255,255,.4);
  color: rgba(255,255,255,.7); border-radius: 4px; padding: 2px 10px;
  font-size: 12px; cursor: pointer;
}
.change-os:hover { background: rgba(255,255,255,.1); }

/* ── Layout ───────────────────────────────────────── */
.layout {
  display: flex;
  min-height: calc(100vh - var(--topbar-h));
}

/* ── Sidebar ──────────────────────────────────────── */
.sidebar {
  width: var(--sidebar-w); flex-shrink: 0;
  background: var(--surface); border-right: 1px solid var(--border);
  padding: 20px 0; display: flex; flex-direction: column;
  position: sticky; top: var(--topbar-h); height: calc(100vh - var(--topbar-h));
  overflow-y: auto;
}
.sidebar-label {
  padding: 0 16px 8px; font-size: 11px; font-weight: 700;
  text-transform: uppercase; letter-spacing: 1px; color: var(--text-muted);
}
.sidebar-lesson {
  display: flex; align-items: center; gap: 10px;
  padding: 8px 16px; font-size: 13px; color: var(--text-muted);
  border-left: 3px solid transparent; transition: background .1s;
}
.sidebar-lesson:hover { background: var(--blue-light); text-decoration: none; color: var(--text); }
.sidebar-lesson.complete { color: var(--text-muted); }
.sidebar-lesson.complete .lesson-icon { color: var(--green); }
.sidebar-lesson.current {
  background: var(--blue-light); border-left-color: var(--blue);
  color: var(--blue); font-weight: 600;
}
.sidebar-lesson.current .lesson-icon { color: var(--blue); }
.lesson-icon { font-size: 12px; width: 16px; text-align: center; flex-shrink: 0; }
.sidebar-progress { padding: 16px 16px 8px; border-top: 1px solid var(--border); margin-top: auto; }
.sidebar-progress-label { font-size: 11px; font-weight: 700; text-transform: uppercase; letter-spacing: 1px; color: var(--text-muted); margin-bottom: 6px; }
.progress-bar { background: var(--border); border-radius: var(--radius-pill); height: 6px; overflow: hidden; }
.progress-fill { background: var(--blue); height: 100%; border-radius: var(--radius-pill); transition: width .3s; }
.progress-text { font-size: 12px; color: var(--text-muted); margin-top: 4px; }
.sidebar-cert-link {
  display: block; margin: 8px 12px; padding: 10px 14px;
  background: linear-gradient(135deg, var(--blue), var(--blue-dark));
  color: var(--white) !important; border-radius: 8px;
  font-size: 13px; font-weight: 600; text-align: center; text-decoration: none;
}
.sidebar-cert-link:hover { opacity: .9; text-decoration: none; }
.sidebar-footer { padding: 12px 16px; border-top: 1px solid var(--border); display: flex; flex-direction: column; gap: 6px; }
.sidebar-footer a, .reset-link {
  font-size: 13px; color: var(--text-muted); background: none; border: none;
  cursor: pointer; padding: 0; text-align: left;
}
.sidebar-footer a:hover, .reset-link:hover { color: var(--text); text-decoration: underline; }

/* ── Main Content ─────────────────────────────────── */
.main-content { flex: 1; padding: 32px 40px; max-width: 780px; margin-right: auto; }
.lesson-title { font-size: 26px; font-weight: 700; margin-bottom: 6px; }
.lesson-intro { color: var(--text-muted); font-size: 15px; margin-bottom: 28px; }
.lesson-section { margin-bottom: 28px; }
.lesson-section h2 { font-size: 18px; font-weight: 600; margin-bottom: 10px; border-bottom: 1px solid var(--border); padding-bottom: 6px; }
.lesson-section p { margin-bottom: 10px; }
.lesson-section ul { padding-left: 20px; }
.lesson-section li { margin-bottom: 4px; }
.callout { background: var(--blue-light); border-left: 4px solid var(--blue); border-radius: 0 6px 6px 0; padding: 12px 16px; margin: 12px 0; font-size: 14px; }
.callout.warning { background: var(--orange-light); border-left-color: var(--orange); }

/* ── Exercise Card ────────────────────────────────── */
.exercise-section-label {
  font-size: 11px; font-weight: 700; text-transform: uppercase;
  letter-spacing: 1px; color: var(--blue); margin-bottom: 12px;
}
.exercise-card {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: 10px; padding: 20px; margin-bottom: 16px;
}
.exercise-header { margin-bottom: 4px; }
.exercise-label { font-size: 12px; font-weight: 600; color: var(--text-muted); text-transform: uppercase; letter-spacing: .5px; }
.exercise-prompt { font-size: 15px; font-weight: 500; margin-bottom: 14px; color: var(--text); }
.terminal-input-row {
  display: flex; align-items: center; gap: 8px;
  background: var(--terminal-bg); border-radius: 6px; padding: 8px 12px;
}
.terminal-prompt { font-family: 'Courier New', monospace; font-size: 12px; color: var(--terminal-prompt-label); white-space: nowrap; flex-shrink: 0; }
.terminal-input {
  flex: 1; background: transparent; border: none; outline: none;
  font-family: 'Courier New', monospace; font-size: 13px; color: var(--terminal-text);
  caret-color: var(--terminal-text);
}
.terminal-input::placeholder { color: var(--terminal-muted); opacity: 1; }
.run-btn {
  background: var(--blue); color: var(--white); border: none; border-radius: 4px;
  padding: 4px 14px; font-size: 13px; font-weight: 600; cursor: pointer; white-space: nowrap;
}
.run-btn:hover { background: var(--blue-dark); }
.terminal-output {
  margin-top: 8px; background: var(--terminal-bg); border-radius: 4px;
  padding: 8px 12px; font-family: 'Courier New', monospace; font-size: 12px;
}
.terminal-output.success .output-status { color: var(--terminal-green); font-weight: 600; margin-bottom: 2px; }
.terminal-output.success .output-text { color: var(--terminal-text); }
.terminal-output.error .output-status { color: var(--terminal-red); }
.exercise-controls { display: flex; align-items: center; gap: 12px; margin-top: 12px; }
.hint-btn, .skip-btn {
  background: none; border: none; cursor: pointer; font-size: 13px; color: var(--text-muted);
}
.hint-btn:hover, .skip-btn:hover { color: var(--text); }
.next-btn {
  margin-left: auto; background: var(--blue); color: var(--white); border: none;
  border-radius: 6px; padding: 6px 16px; font-size: 13px; font-weight: 600; cursor: pointer;
}
.next-btn:hover { background: var(--blue-dark); }
.hint-text { margin-top: 10px; font-size: 13px; color: var(--text-muted); background: var(--orange-light); border-radius: 4px; padding: 8px 12px; }
.ex-dots { display: flex; gap: 6px; margin-top: 14px; align-items: center; }
.ex-dot { width: 8px; height: 8px; border-radius: var(--radius-pill); background: var(--border); }
.ex-dot.done { background: var(--green); }
.ex-dot.active { background: var(--blue); }

/* ── Lesson Complete ──────────────────────────────── */
.lesson-complete { text-align: center; padding: 48px 24px; }
.complete-icon { font-size: 48px; margin-bottom: 12px; }
.lesson-complete h2 { font-size: 24px; margin-bottom: 8px; }
.lesson-complete p { color: var(--text-muted); margin-bottom: 24px; }
.next-lesson-btn {
  display: inline-block; background: var(--blue); color: var(--white);
  padding: 10px 28px; border-radius: 8px; font-weight: 600; font-size: 15px;
}
.next-lesson-btn:hover { background: var(--blue-dark); text-decoration: none; }

/* ── Free Terminal (Lesson 5) ─────────────────────── */
.challenge-stack { display: flex; flex-direction: column; gap: 20px; }
.challenge-goal {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 20px;
}
.challenge-goal h2 { font-size: 16px; font-weight: 700; margin-bottom: 8px; }
.challenge-goal pre { background: var(--code-bg); border: 1px solid var(--border); border-radius: 6px; padding: 12px; font-size: 13px; overflow-x: auto; margin-top: 10px; }
.checklist { background: var(--surface); border: 1px solid var(--border); border-radius: 8px; padding: 16px; }
.hint-accordion { border: 1px solid var(--border); border-radius: 8px; margin-top: 12px; overflow: hidden; }
.hint-accordion summary { padding: 12px 16px; font-size: 14px; font-weight: 600; color: var(--text-muted); cursor: pointer; user-select: none; list-style: none; display: flex; align-items: center; gap: 8px; }
.hint-accordion summary::-webkit-details-marker { display: none; }
.hint-accordion[open] summary { color: var(--text); border-bottom: 1px solid var(--border); }
.hint-accordion > ol { padding: 12px 16px 12px 36px; margin: 0; background: var(--surface); }
.hint-accordion summary::after { content: '▸'; margin-left: auto; font-size: 11px; transition: transform .15s; }
.hint-accordion[open] summary::after { transform: rotate(90deg); }
.checklist h3 { font-size: 13px; font-weight: 700; text-transform: uppercase; letter-spacing: .5px; color: var(--text-muted); margin-bottom: 10px; }
.checklist-item { display: flex; align-items: center; gap: 10px; padding: 5px 0; font-size: 14px; color: var(--text-muted); border-bottom: 1px solid var(--border); }
.checklist-item:last-child { border-bottom: none; }
.checklist-item.done { color: var(--green); }
.checklist-item .check-icon::before { content: '○'; color: var(--text-faint); }
.checklist-item.done .check-icon::before { content: '✓'; color: var(--green); }
.free-terminal-box { background: var(--terminal-bg); border-radius: 8px; overflow: hidden; }
.free-terminal-header { background: var(--terminal-chrome); padding: 8px 12px; display: flex; justify-content: space-between; align-items: center; }
.free-terminal-title { font-size: 12px; color: var(--terminal-muted); font-family: 'Courier New', monospace; }
.reset-terminal-btn { background: none; border: 1px solid var(--terminal-border); border-radius: 4px; color: var(--text-muted); font-size: 11px; padding: 2px 8px; cursor: pointer; }
.reset-terminal-btn:hover { color: var(--terminal-faint); border-color: #475569; }
.free-terminal-output { padding: 10px 12px; font-family: 'Courier New', monospace; font-size: 12px; min-height: 280px; max-height: 360px; overflow-y: auto; display: flex; flex-direction: column; gap: 2px; }
.free-terminal-output .ft-line { color: var(--terminal-faint); }
.free-terminal-output .ft-cmd { color: var(--terminal-text); }
.free-terminal-output .ft-out { color: var(--terminal-muted); }
.free-terminal-output .ft-err { color: var(--terminal-red); }
.free-terminal-output .ft-success { color: var(--terminal-green); font-size: 11px; }
.free-terminal-input-row {
  display: flex; align-items: center; gap: 6px;
  padding: 8px 12px; border-top: 1px solid var(--terminal-chrome);
}
.free-terminal-prompt-text { font-family: 'Courier New', monospace; font-size: 12px; color: var(--terminal-prompt-label); white-space: nowrap; flex-shrink: 0; }
.free-terminal-input {
  flex: 1; background: transparent; border: none; outline: none;
  font-family: 'Courier New', monospace; font-size: 12px; color: var(--terminal-text); caret-color: var(--terminal-text);
}
.free-terminal-input::placeholder { color: var(--terminal-muted); opacity: 1; }
.free-run-btn { background: var(--blue); color: var(--white); border: none; border-radius: 4px; padding: 3px 10px; font-size: 11px; cursor: pointer; }

/* ── Index / Dashboard ────────────────────────────── */
.dashboard-intro { margin-bottom: 32px; }
.dashboard-intro h1 { font-size: 28px; font-weight: 700; margin-bottom: 8px; }
.dashboard-intro p { color: var(--text-muted); max-width: 520px; }
.lesson-cards { display: flex; flex-direction: column; gap: 12px; }
.lesson-card {
  display: flex; align-items: center; gap: 16px;
  background: var(--surface); border: 1px solid var(--border);
  border-radius: 10px; padding: 16px 20px; text-decoration: none; color: var(--text);
  transition: border-color .15s, box-shadow .15s;
}
.lesson-card:hover { border-color: var(--blue); box-shadow: 0 2px 8px rgba(247,105,0,.15); text-decoration: none; }
.lesson-card.complete { border-left: 4px solid var(--green); }
.lesson-card.in-progress { border-left: 4px solid var(--blue); }
.card-icon { font-size: 20px; width: 32px; text-align: center; flex-shrink: 0; }
.card-body { flex: 1; }
.card-title { font-weight: 600; font-size: 15px; }
.card-desc { font-size: 13px; color: var(--text-muted); }
.card-status { font-size: 12px; font-weight: 600; padding: 2px 10px; border-radius: var(--radius-pill); }
.card-status.complete { background: var(--green-light); color: #15803d; }
.card-status.in-progress { background: var(--blue-light); color: var(--blue); }
.cert-card { background: linear-gradient(135deg, var(--blue) 0%, var(--blue-dark) 100%); color: var(--white); border: none; margin-top: 8px; }
.cert-card:hover { border-color: transparent; box-shadow: 0 4px 16px rgba(247,105,0,.35); }
.cert-card .card-title { color: var(--white); }

/* ── Certificate Page ─────────────────────────────── */
.cert-locked {
  text-align: center; padding: 60px 24px;
  border: 1px solid var(--border); border-radius: 10px;
  background: var(--surface); max-width: 480px;
}
.cert-locked-icon { font-size: 40px; margin-bottom: 12px; }
.cert-locked h2 { font-size: 20px; font-weight: 700; margin-bottom: 8px; }
.cert-locked p { color: var(--text-muted); margin-bottom: 24px; }
.cert-intro { margin-bottom: 32px; }
.cert-name-form { display: flex; gap: 10px; margin-top: 16px; flex-wrap: wrap; }
.cert-name-input {
  flex: 1; min-width: 220px; padding: 10px 14px;
  border: 1px solid var(--border); border-radius: 8px;
  font-size: 15px; color: var(--text); outline: none;
}
.cert-name-input:focus { border-color: var(--blue); box-shadow: 0 0 0 3px rgba(247,105,0,.15); }
.cert-generate-btn {
  background: var(--blue); color: var(--white); border: none;
  border-radius: 8px; padding: 10px 22px; font-size: 15px;
  font-weight: 600; cursor: pointer;
}
.cert-generate-btn:hover { background: var(--blue-dark); }
.certificate { margin: 24px 0 16px; }
.cert-border-outer {
  border: 6px double var(--blue);
  border-radius: 4px;
  padding: 6px;
  background: #fff;
  box-shadow: 0 4px 24px rgba(0,0,0,.1);
  max-width: 680px;
  overflow: hidden;
}
.cert-header {
  background: var(--navy);
  padding: 22px 40px;
  text-align: center;
  border-bottom: 3px solid var(--blue);
}
.cert-logo { max-height: 64px; width: auto; }
.cert-content-row { display: flex; align-items: stretch; background: #fefefe; }
.cert-main {
  flex: 1; min-width: 0;
  padding: 28px 36px 28px;
  text-align: center;
}
.cert-sidebar {
  width: 130px; flex-shrink: 0;
  background: var(--blue-light);
  border-left: 2px solid var(--blue-mid);
  display: flex; flex-direction: column;
  align-items: center; justify-content: center;
  gap: 8px; padding: 20px 12px;
}
.cert-heading {
  font-size: 10px; font-weight: 700; letter-spacing: 3px;
  text-transform: uppercase; color: var(--text-muted); margin-bottom: 20px;
}
.cert-presented { font-size: 13px; color: var(--text-muted); margin-bottom: 6px; }
.cert-name {
  font-size: 30px; font-weight: 700; color: var(--text);
  border-bottom: 2px solid var(--border); padding-bottom: 8px;
  margin: 0 auto 14px; display: inline-block; min-width: 260px;
}
.cert-course { font-size: 20px; font-weight: 700; color: var(--blue); margin: 6px 0 12px; }
.cert-edition {
  display: inline-block; font-size: 11px; font-weight: 600;
  letter-spacing: 1px; text-transform: uppercase;
  color: var(--blue); border: 1px solid var(--blue-mid);
  background: var(--blue-light); border-radius: var(--radius-pill);
  padding: 3px 12px; margin-bottom: 14px;
}
.cert-desc { font-size: 12px; color: var(--text-muted); line-height: 1.6; margin-bottom: 20px; }
.cert-date { font-size: 12px; color: var(--text-faint); font-style: italic; }
.cert-qr-label { font-size: 9px; color: var(--blue); text-transform: uppercase; letter-spacing: .5px; text-align: center; }
.cert-actions { display: flex; gap: 12px; align-items: center; margin-bottom: 32px; }
.cert-print-btn {
  background: var(--blue); color: var(--white); border: none;
  border-radius: 8px; padding: 10px 22px; font-size: 14px;
  font-weight: 600; cursor: pointer;
}
.cert-print-btn:hover { background: var(--blue-dark); }
.cert-edit-btn {
  background: none; border: 1px solid var(--border); border-radius: 8px;
  padding: 10px 18px; font-size: 14px; color: var(--text-muted); cursor: pointer;
}
.cert-edit-btn:hover { border-color: var(--blue); color: var(--blue); }

/* ── Print ────────────────────────────────────────── */
@media print {
  .no-print { display: none !important; }
  .topbar { display: none !important; }
  .sidebar { display: none !important; }
  .layout { display: block !important; }
  .main-content { padding: 0 !important; max-width: none !important; }
  body { background: white !important; }
  .certificate { margin: 0 !important; }
  .cert-border-outer {
    box-shadow: none !important;
    max-width: 100% !important;
    page-break-inside: avoid;
  }
  @page { size: letter portrait; margin: 0.6in; }
}