/* ── BASE STYLES (oop-java-course.css embedded) ── */
:root {
  --bg: #0f0e17;
  --surface: #1a1830;
  --card: #221f38;
  --accent1: #ff6b6b;
  --accent2: #ffd166;
  --accent3: #06d6a0;
  --accent4: #118ab2;
  --accent5: #c77dff;
  --text: #fffffe;
  --muted: #a7a9be;
  --code-bg: #13111f;
  --border: #2e2b4a;
}
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
body { font-family: 'Nunito', sans-serif; background: var(--bg); color: var(--text); line-height: 1.7; overflow-x: hidden; }

/* HEADER */
header { background: linear-gradient(135deg, #1a0533 0%, #0a1628 50%, #001a12 100%); padding: 60px 40px 80px; text-align: center; position: relative; overflow: hidden; }
header::before { content: ''; position: absolute; inset: 0; background: radial-gradient(circle at 30% 50%, rgba(199,125,255,0.15) 0%, transparent 60%), radial-gradient(circle at 70% 30%, rgba(6,214,160,0.12) 0%, transparent 50%); }
.header-badge { display: inline-block; background: linear-gradient(90deg, var(--accent5), var(--accent3)); color: var(--bg); font-weight: 800; font-size: 13px; letter-spacing: 2px; text-transform: uppercase; padding: 6px 18px; border-radius: 20px; margin-bottom: 20px; }
header h1 { font-family: 'Fredoka One', cursive; font-size: clamp(2.4rem, 6vw, 4.5rem); background: linear-gradient(135deg, #fff 30%, var(--accent5) 70%, var(--accent3)); -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text; line-height: 1.1; margin-bottom: 16px; }
header p { font-size: 1.15rem; color: var(--muted); max-width: 560px; margin: 0 auto 32px; }
.header-stars { font-size: 1.6rem; letter-spacing: 6px; opacity: 0.7; }

/* PROGRESS BAR */
.progress-bar-wrap { background: var(--surface); padding: 14px 40px; display: flex; align-items: center; gap: 16px; border-bottom: 1px solid var(--border); position: sticky; top: 0; z-index: 100; }
.progress-label { font-size: 13px; font-weight: 700; color: var(--muted); white-space: nowrap; }
.progress-track { flex: 1; height: 8px; background: var(--card); border-radius: 10px; overflow: hidden; }
.progress-fill { height: 100%; background: linear-gradient(90deg, var(--accent5), var(--accent3)); border-radius: 10px; transition: width 0.5s ease; width: 0%; }
.progress-pct { font-size: 13px; font-weight: 800; color: var(--accent3); }

/* LAYOUT */
.layout { display: flex; max-width: 1200px; margin: 0 auto; gap: 0; }

/* SIDEBAR */
.sidebar { width: 270px; flex-shrink: 0; padding: 30px 20px; position: sticky; top: 53px; height: calc(100vh - 53px); overflow-y: auto; border-right: 1px solid var(--border); }
.sidebar-title { font-size: 11px; font-weight: 800; letter-spacing: 2px; text-transform: uppercase; color: var(--muted); margin-bottom: 16px; padding-left: 8px; }
.nav-item { display: flex; align-items: center; gap: 10px; padding: 10px 12px; border-radius: 10px; cursor: pointer; transition: all 0.2s; margin-bottom: 4px; font-size: 14px; font-weight: 600; color: var(--muted); text-decoration: none; }
.nav-item:hover { background: var(--card); color: var(--text); }
.nav-item.active { background: var(--card); color: var(--text); border-left: 3px solid var(--accent5); }
.nav-item .nav-icon { font-size: 18px; flex-shrink: 0; }
.nav-item .nav-check { margin-left: auto; font-size: 14px; color: var(--accent3); }

/* MAIN */
.main { flex: 1; padding: 40px 50px; min-width: 0; }

/* LESSONS */
.lesson { display: none; animation: fadeIn 0.4s ease; }
.lesson.active { display: block; }
@keyframes fadeIn { from { opacity: 0; transform: translateY(12px); } to { opacity: 1; transform: translateY(0); } }
.lesson-header { margin-bottom: 36px; }
.lesson-num { font-size: 12px; font-weight: 800; letter-spacing: 2px; text-transform: uppercase; color: var(--accent5); margin-bottom: 8px; }
.lesson h2 { font-family: 'Fredoka One', cursive; font-size: clamp(1.8rem, 3vw, 2.8rem); line-height: 1.15; margin-bottom: 12px; }
.lesson-intro { font-size: 1.05rem; color: var(--muted); max-width: 680px; border-left: 3px solid var(--accent5); padding-left: 16px; }

/* CARDS */
.card { background: var(--card); border: 1px solid var(--border); border-radius: 16px; padding: 28px; margin-bottom: 28px; }
.card-title { font-family: 'Fredoka One', cursive; font-size: 1.25rem; margin-bottom: 14px; display: flex; align-items: center; gap: 10px; }
.card p, .card li { font-size: 0.97rem; color: #d4d4e8; margin-bottom: 10px; }
.card ul, .card ol { padding-left: 20px; }
.card li { margin-bottom: 6px; }

/* CALLOUTS */
.callout { border-radius: 14px; padding: 20px 24px; margin: 20px 0; display: flex; gap: 14px; align-items: flex-start; }
.callout-emoji { font-size: 1.5rem; flex-shrink: 0; margin-top: 2px; }
.callout-body { font-size: 0.95rem; }
.callout-body strong { display: block; font-size: 1rem; margin-bottom: 4px; }
.callout.tip { background: rgba(6,214,160,0.1); border: 1px solid rgba(6,214,160,0.25); }
.callout.tip .callout-body strong { color: var(--accent3); }
.callout.warn { background: rgba(255,209,102,0.1); border: 1px solid rgba(255,209,102,0.25); }
.callout.warn .callout-body strong { color: var(--accent2); }
.callout.fun { background: rgba(199,125,255,0.1); border: 1px solid rgba(199,125,255,0.25); }
.callout.fun .callout-body strong { color: var(--accent5); }
.callout.info { background: rgba(17,138,178,0.12); border: 1px solid rgba(17,138,178,0.3); }
.callout.info .callout-body strong { color: #5bc4e8; }

/* CODE BLOCKS */
.code-block { background: var(--code-bg); border: 1px solid var(--border); border-radius: 12px; margin: 18px 0; overflow: hidden; }
.code-header { background: #1c1929; padding: 10px 18px; display: flex; align-items: center; justify-content: space-between; border-bottom: 1px solid var(--border); }
.code-lang { font-size: 12px; font-weight: 700; color: var(--accent5); letter-spacing: 1px; text-transform: uppercase; }
.code-dots { display: flex; gap: 6px; }
.code-dots span { width: 10px; height: 10px; border-radius: 50%; }
.code-dots span:nth-child(1) { background: #ff5f56; }
.code-dots span:nth-child(2) { background: #ffbd2e; }
.code-dots span:nth-child(3) { background: #27c93f; }
pre { padding: 20px 22px; overflow-x: auto; font-family: 'Fira Code', monospace; font-size: 0.88rem; line-height: 1.8; }

/* QUIZ */
.quiz-block { background: linear-gradient(135deg, #1a1830, #1e1535); border: 1px solid var(--accent5); border-radius: 16px; padding: 28px; margin: 28px 0; }
.quiz-title { font-family: 'Fredoka One', cursive; font-size: 1.2rem; color: var(--accent5); margin-bottom: 14px; display: flex; align-items: center; gap: 8px; }
.quiz-q { font-size: 1rem; font-weight: 700; margin-bottom: 16px; }
.quiz-options { display: flex; flex-direction: column; gap: 10px; }
.quiz-option { background: var(--card); border: 2px solid var(--border); border-radius: 10px; padding: 12px 18px; cursor: pointer; font-size: 0.95rem; font-weight: 600; transition: all 0.2s; text-align: left; color: var(--text); font-family: 'Nunito', sans-serif; }
.quiz-option:hover { border-color: var(--accent5); background: rgba(199,125,255,0.08); }
.quiz-option.correct { border-color: var(--accent3); background: rgba(6,214,160,0.12); color: var(--accent3); }
.quiz-option.wrong { border-color: var(--accent1); background: rgba(255,107,107,0.1); color: var(--accent1); }
.quiz-feedback { margin-top: 14px; padding: 12px 16px; border-radius: 10px; font-weight: 700; font-size: 0.95rem; display: none; }
.quiz-feedback.show { display: block; }
.quiz-feedback.ok { background: rgba(6,214,160,0.15); color: var(--accent3); border: 1px solid var(--accent3); }
.quiz-feedback.bad { background: rgba(255,107,107,0.1); color: var(--accent1); border: 1px solid var(--accent1); }

/* CHALLENGE */
.challenge { background: linear-gradient(135deg, rgba(17,138,178,0.12), rgba(6,214,160,0.08)); border: 1px solid rgba(17,138,178,0.3); border-radius: 14px; padding: 24px 28px; margin: 24px 0; }
.challenge-label { font-size: 11px; font-weight: 800; letter-spacing: 2px; text-transform: uppercase; color: #5bc4e8; margin-bottom: 8px; }
.challenge h4 { font-size: 1.05rem; margin-bottom: 10px; }
.challenge p, .challenge li { font-size: 0.95rem; color: #ccc; }
.challenge ul { padding-left: 20px; }
.challenge li { margin-bottom: 6px; }

/* NAV BUTTONS */
.lesson-nav { display: flex; justify-content: space-between; margin-top: 50px; padding-top: 28px; border-top: 1px solid var(--border); }
.btn { padding: 12px 28px; border-radius: 12px; font-family: 'Nunito', sans-serif; font-size: 0.95rem; font-weight: 800; cursor: pointer; border: none; transition: all 0.2s; }
.btn-next { background: linear-gradient(135deg, var(--accent5), var(--accent4)); color: white; }
.btn-next:hover { transform: translateY(-2px); box-shadow: 0 8px 24px rgba(199,125,255,0.3); }
.btn-prev { background: var(--card); color: var(--muted); border: 1px solid var(--border); }
.btn-prev:hover { color: var(--text); border-color: var(--accent5); }
.btn:disabled { opacity: 0.3; cursor: not-allowed; transform: none !important; box-shadow: none !important; }

/* TABLE */
table { width: 100%; border-collapse: collapse; font-size: 0.92rem; margin: 16px 0; }
th { background: var(--surface); color: var(--accent5); font-weight: 800; padding: 12px 16px; text-align: left; border-bottom: 2px solid var(--border); }
td { padding: 11px 16px; border-bottom: 1px solid var(--border); color: #d4d4e8; }
tr:hover td { background: rgba(255,255,255,0.02); }

/* SCROLLBAR */
::-webkit-scrollbar { width: 6px; height: 6px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--border); border-radius: 3px; }

/* MOBILE */
@media (max-width: 768px) {
  .sidebar { display: none; }
  .main { padding: 24px 20px; }
  .progress-bar-wrap { padding: 10px 20px; }
  header { padding: 40px 20px 60px; }
}

/* ── Phase 2 overrides ── */
:root {
  --py:       #ffd166;
  --py-dim:   #ffaa33;
  --py-blue:  #4db8ff;
  --py-teal:  #06d6a0;
  --py-purple:#c77dff;
}

.header-badge { background: linear-gradient(90deg, var(--py-purple), var(--py)); color: #0f0e17; }
header { background: linear-gradient(135deg, #120a28 0%, #0f0e17 45%, #001a12 100%); }
header::before {
  background:
    radial-gradient(circle at 20% 60%, rgba(199,125,255,0.18) 0%, transparent 55%),
    radial-gradient(circle at 80% 25%, rgba(255,209,102,0.14) 0%, transparent 50%);
}
header h1 {
  background: linear-gradient(135deg, #fff 15%, var(--py-purple) 50%, var(--py));
  -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text;
}
.nav-item.active { border-left-color: var(--py-purple); }
.lesson-num { color: var(--py-purple); }

/* ── streak bar ── */
.streak-bar {
  display: flex; align-items: center; gap: 6px;
  padding: 12px 20px 18px;
  border-bottom: 1px solid var(--border);
}
.streak-label { font-size: 10px; font-weight: 800; letter-spacing: 2px; text-transform: uppercase; color: var(--muted); margin-right: 4px; }
.streak-node { width: 10px; height: 10px; border-radius: 50%; background: var(--border); border: 2px solid var(--border); transition: all 0.3s ease; flex-shrink: 0; }
.streak-node.done    { background: var(--py-purple); border-color: var(--py-purple); box-shadow: 0 0 8px rgba(199,125,255,0.6); }
.streak-node.current { background: transparent; border-color: var(--py-purple); animation: pulse-node 1.5s ease-in-out infinite; }
@keyframes pulse-node {
  0%,100% { box-shadow: 0 0 0 0 rgba(199,125,255,0.4); }
  50%      { box-shadow: 0 0 0 5px rgba(199,125,255,0); }
}

/* ── syntax highlighting ── */
.kw  { color: #c77dff; }
.fn  { color: #06d6a0; }
.str { color: #ffaa6b; }
.cm  { color: #4a4870; font-style: italic; }
.num { color: #ff6b9d; }
.cls { color: #ffd166; }
.bi  { color: #4db8ff; }
.out { color: #a7f3d0; }
.dec { color: #ff6b6b; }
.op  { color: #e8e8f0; }

/* ── layout helpers ── */
.compare-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; margin: 18px 0; }
.compare-label { font-size: 11px; font-weight: 800; letter-spacing: 2px; text-transform: uppercase; padding: 8px 16px; border-radius: 8px 8px 0 0; }
.compare-label.bad-lbl    { background: rgba(255,107,107,0.12); color: #ff6b6b; }
.compare-label.good-lbl   { background: rgba(6,214,160,0.12);   color: var(--py-teal); }
.compare-label.java-lbl   { background: rgba(255,107,107,0.12); color: #ff6b6b; }
.compare-label.python-lbl { background: rgba(255,209,102,0.12); color: var(--py); }
.compare-col .code-block  { margin-top: 0; border-radius: 0 0 12px 12px; border-top: none; }

.insight-row { display: grid; grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); gap: 14px; margin: 20px 0; }
.insight-card { background: var(--card); border: 1px solid var(--border); border-radius: 12px; padding: 18px; border-top: 2px solid var(--py-purple); transition: transform 0.2s; }
.insight-card:hover { transform: translateY(-3px); }
.insight-card .ic-icon { font-size: 1.6rem; margin-bottom: 10px; }
.insight-card h5 { font-family: 'Fredoka One', cursive; font-size: 0.95rem; margin-bottom: 6px; color: var(--py-purple); }
.insight-card p  { font-size: 0.83rem; color: var(--muted); line-height: 1.65; }

.try-it { background: linear-gradient(135deg, rgba(199,125,255,0.06), rgba(255,209,102,0.04)); border: 1px solid rgba(199,125,255,0.2); border-radius: 14px; padding: 22px 26px; margin: 22px 0; }
.try-it-label { font-size: 10px; font-weight: 800; letter-spacing: 2px; text-transform: uppercase; color: var(--py-purple); margin-bottom: 10px; }
.try-it h4 { font-family: 'Fredoka One', cursive; font-size: 1.05rem; margin-bottom: 8px; }
.try-it p, .try-it li { font-size: 0.92rem; color: #ccc; line-height: 1.75; }
.try-it ul, .try-it ol { padding-left: 20px; }
.try-it li { margin-bottom: 6px; }

.step-list { counter-reset: step; list-style: none; padding: 0; }
.step-list li { counter-increment: step; display: flex; gap: 14px; padding: 13px 0; border-bottom: 1px solid var(--border); font-size: 0.95rem; color: #d4d4e8; line-height: 1.7; }
.step-list li::before { content: counter(step); display: flex; align-items: center; justify-content: center; width: 26px; height: 26px; background: linear-gradient(135deg, var(--py-purple), var(--py)); color: #0f0e17; font-weight: 900; font-size: 12px; border-radius: 50%; flex-shrink: 0; margin-top: 3px; }

/* ── deep-dive box (new for Phase 2) ── */
.deep-dive {
  background: linear-gradient(135deg, rgba(199,125,255,0.07), rgba(77,184,255,0.05));
  border: 1px solid rgba(199,125,255,0.22);
  border-left: 4px solid var(--py-purple);
  border-radius: 0 14px 14px 0;
  padding: 22px 26px;
  margin: 20px 0;
}
.deep-dive-label { font-size: 10px; font-weight: 800; letter-spacing: 2px; text-transform: uppercase; color: var(--py-purple); margin-bottom: 10px; }
.deep-dive h4 { font-family: 'Fredoka One', cursive; font-size: 1.08rem; margin-bottom: 10px; }
.deep-dive p, .deep-dive li { font-size: 0.93rem; color: #ccc; line-height: 1.8; margin-bottom: 8px; }
.deep-dive ul { padding-left: 20px; }
.deep-dive li { margin-bottom: 5px; }

/* ── "how it works under the hood" box ── */
.hood {
  background: rgba(0,0,0,0.25);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 18px 22px;
  margin: 16px 0;
  font-size: 0.9rem;
  color: #b8b8d0;
  line-height: 1.8;
}
.hood-label { font-size: 10px; font-weight: 800; letter-spacing: 2px; text-transform: uppercase; color: var(--muted); margin-bottom: 8px; }

/* ── output block ── */
.output-block {
  background: #0a0a14;
  border: 1px solid var(--border);
  border-left: 3px solid var(--py-teal);
  border-radius: 0 10px 10px 0;
  padding: 14px 20px;
  font-family: 'Fira Code', monospace;
  font-size: 0.84rem;
  color: var(--out);
  line-height: 1.9;
  margin: -2px 0 16px;
}
.output-block::before { content: '▶ Output'; display: block; font-size: 10px; font-weight: 800; letter-spacing: 2px; text-transform: uppercase; color: var(--py-teal); margin-bottom: 8px; opacity: 0.7; }

/* ── pill badges ── */
.pill { display: inline-block; padding: 2px 10px; border-radius: 20px; font-size: 11px; font-weight: 800; letter-spacing: 0.5px; }
.pill-purple { background: rgba(199,125,255,0.12); color: var(--py-purple); border: 1px solid rgba(199,125,255,0.3); }
.pill-gold   { background: rgba(255,209,102,0.12); color: var(--py); border: 1px solid rgba(255,209,102,0.3); }
.pill-green  { background: rgba(6,214,160,0.12);  color: var(--py-teal); border: 1px solid rgba(6,214,160,0.3); }
.pill-red    { background: rgba(255,107,107,0.12); color: #ff6b6b; border: 1px solid rgba(255,107,107,0.3); }

@media (max-width: 680px) {
  .compare-grid { grid-template-columns: 1fr; }
  .sidebar { display: none; }
  .main { padding: 22px 16px; }
}