:root {
  --bg-main: #282a36; --bg-sidebar: #1e1f29; --bg-card: #44475a; --bg-code: #21222c;
  --drac-comment: #6272a4; --drac-cyan: #8be9fd; --drac-green: #50fa7b; 
  --drac-orange: #ffb86c; --drac-pink: #ff79c6; --drac-purple: #bd93f9; 
  --drac-red: #ff5555; --drac-yellow: #f1fa8c; --text-main: #f8f8f2;
  --border-color: rgba(98, 114, 164, 0.3);
  --font-sans: 'Inter', system-ui, sans-serif; --font-mono: 'Fira Code', monospace;
  --shadow-md: 0 10px 25px rgba(0,0,0,0.5);
}

* { margin: 0; padding: 0; box-sizing: border-box; }
body { background-color: var(--bg-main); color: var(--text-main); font-family: var(--font-sans); height: 100vh; overflow: hidden; -webkit-font-smoothing: antialiased; font-size: 15px; }
.cite-ref { display: none !important; }

.app-container { display: flex; height: 100vh; width: 100%; position: relative; }

/* HOVER SIDEBAR LOGIC */
.hover-trigger { position: fixed; left: 0; top: 0; width: 25px; height: 100vh; z-index: 99; }
.sidebar { position: fixed; left: 0; top: 0; width: 300px; height: 100vh; background: var(--bg-sidebar); border-right: 1px solid var(--border-color); display: flex; flex-direction: column; z-index: 100; transform: translateX(-100%); transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1); box-shadow: var(--shadow-md); }
.sidebar.hover-open, .sidebar.open { transform: translateX(0); }

/* MAIN EXPANDED CONTENT */
.main-content { flex: 1; display: flex; flex-direction: column; height: 100vh; overflow-y: auto; scroll-behavior: smooth; margin-left: 0; padding-left: 15px; width: 100%; }

.brand { display: flex; align-items: center; justify-content: center; padding: 25px 20px; border-bottom: 1px solid var(--border-color); text-align: center; }
.brand-text h1 { font-size: 1.2rem; font-weight: 700; letter-spacing: 1px; }
.brand-text h1 span { color: var(--drac-purple); }
.brand-text p { font-size: 0.7rem; color: var(--drac-comment); margin-top: 4px; font-family: var(--font-mono); }

.search-box { padding: 16px 20px; }
.search-box input { width: 100%; background: var(--bg-code); border: 1px solid var(--border-color); padding: 10px 14px; border-radius: 8px; color: var(--text-main); font-family: var(--font-sans); font-size: 0.85rem; outline: none; transition: 0.2s; }
.search-box input:focus { border-color: var(--drac-purple); box-shadow: 0 0 0 2px rgba(189, 147, 249, 0.2); }
.search-shortcut { position: absolute; right: 12px; top: 50%; transform: translateY(-50%); color: var(--drac-comment); font-size: 0.65rem; font-family: var(--font-mono); border: 1px solid var(--border-color); padding: 2px 4px; border-radius: 4px; background: var(--bg-sidebar); }

.sidebar-nav { flex: 1; overflow-y: auto; padding: 10px 16px 20px; }
.sidebar-nav::-webkit-scrollbar { width: 4px; }
.sidebar-nav::-webkit-scrollbar-thumb { background: var(--drac-comment); border-radius: 4px; }

.section-group { margin-bottom: 18px; }
.section-title { font-size: 0.7rem; text-transform: uppercase; color: var(--drac-purple); padding: 4px 8px; font-weight: 700; letter-spacing: 0.5px; opacity: 0.9; }
.lesson-link { display: flex; align-items: center; justify-content: space-between; padding: 10px 12px; border-radius: 8px; text-decoration: none; color: var(--drac-comment); font-size: 0.85rem; margin-bottom: 4px; cursor: pointer; transition: 0.2s; border: 1px solid transparent; }
.lesson-link:hover { background: rgba(189, 147, 249, 0.08); color: var(--text-main); }
.lesson-link.active { background: var(--bg-card); color: var(--drac-cyan); border-color: var(--border-color); }
.lesson-name { display: flex; align-items: center; gap: 6px; }
.status-check { display: none; color: var(--drac-green); font-size: 0.8rem; }
.lesson-link.completed .status-check { display: inline-block; }
.badge-pill { font-size: 0.6rem; padding: 3px 8px; border-radius: 12px; font-family: var(--font-mono); font-weight: 600; }
.badge-pill.theory { background: rgba(255, 121, 198, 0.1); color: var(--drac-pink); border: 1px solid rgba(255, 121, 198, 0.2); }
.badge-pill.interactive { background: rgba(139, 233, 253, 0.1); color: var(--drac-cyan); border: 1px solid rgba(139, 233, 253, 0.2); }

.sidebar-contact { padding: 20px; border-top: 1px solid var(--border-color); text-align: center; }
.social-icons { display: flex; justify-content: center; gap: 16px; }
.social-icon { color: var(--drac-comment); transition: all 0.2s; }
.social-icon:hover { transform: translateY(-3px); }
.social-icon.github:hover { color: #fff; }
.social-icon.linkedin:hover { color: #0a66c2; }

.top-header { padding: 16px 30px; display: flex; justify-content: space-between; align-items: center; border-bottom: 1px solid var(--border-color); background: rgba(40, 42, 54, 0.9); backdrop-filter: blur(10px); position: sticky; top: 0; z-index: 10; }
.header-left, .header-right { display: flex; align-items: center; gap: 16px; }
.menu-toggle { display: block; background: transparent; border: 1px solid var(--border-color); border-radius: 6px; color: var(--text-main); cursor: pointer; padding: 6px; transition: 0.2s; }
.menu-toggle:hover { border-color: var(--drac-cyan); color: var(--drac-cyan); background: var(--bg-card); }
.breadcrumbs { font-size: 0.8rem; color: var(--drac-comment); }
.breadcrumbs .active { color: var(--drac-cyan); font-weight: 500; }
.lang-toggle { display: flex; align-items: center; gap: 6px; background: var(--bg-card); border: 1px solid var(--border-color); color: var(--text-main); padding: 6px 12px; border-radius: 20px; font-size: 0.75rem; font-family: var(--font-mono); cursor: pointer; transition: 0.2s; }
.lang-toggle:hover { border-color: var(--drac-purple); color: var(--drac-purple); }
.pulse-dot { width: 10px; height: 10px; background: var(--drac-green); border-radius: 50%; box-shadow: 0 0 10px var(--drac-green); animation: pulse 2s infinite; }

/* FIX FOR DISAPPEARING TABS */
.lesson-viewer { padding: 40px 5%; max-width: 1000px; margin: 0 auto; width: 100%; display: flex; flex-direction: column; min-height: 100%; min-width: 0; }
.lesson-header { margin-bottom: 24px; flex-shrink: 0; }
.meta-tags { display: flex; gap: 8px; margin-bottom: 12px; }
.tag { font-family: var(--font-mono); font-size: 0.7rem; padding: 4px 10px; border-radius: 6px; font-weight: 600; border: 1px solid var(--border-color); }
.tag-id { background: var(--bg-card); color: var(--drac-purple); }
.tag-type { color: var(--drac-comment); }
.lesson-header h2 { font-size: 2.2rem; font-weight: 700; line-height: 1.2; color: var(--text-main); }

.tabs-container { display: flex; gap: 10px; border-bottom: 1px solid var(--border-color); margin-bottom: 30px; overflow-x: auto; flex-shrink: 0; }
.tabs-container::-webkit-scrollbar { height: 0; }
.tab-btn { background: transparent; border: none; padding: 12px 18px; color: var(--drac-comment); font-size: 0.95rem; font-weight: 500; cursor: pointer; border-bottom: 2px solid transparent; transition: 0.2s; white-space: nowrap; }
.tab-btn:hover { color: var(--text-main); }
.tab-btn.active { color: var(--drac-purple); border-bottom: 2px solid var(--drac-purple); color: var(--drac-purple); font-weight: 600; }
.tab-pane { display: none; animation: fadeIn 0.4s ease; flex: 1; min-width: 0; }
.tab-pane.active { display: block; }
@keyframes fadeIn { from { opacity: 0; transform: translateY(10px); } to { opacity: 1; transform: translateY(0); } }

/* MARKDOWN OPTIMIZADO */
.notes-layout { display: flex; gap: 40px; align-items: flex-start; }
.markdown-body { flex: 1; min-width: 0; line-height: 1.7; font-size: 1.05rem; color: #f8f8f2; }
.markdown-body h1, .markdown-body h2 { color: var(--drac-purple); margin: 36px 0 16px 0; border-bottom: 1px solid var(--border-color); padding-bottom: 8px; font-size: 1.6rem; font-weight: 600; }
.markdown-body h3 { color: var(--drac-cyan); margin: 24px 0 12px 0; font-size: 1.2rem; }
.markdown-body p, .markdown-body ul { margin-bottom: 16px; }
.markdown-body ul { padding-left: 24px; }
.markdown-body li { margin-bottom: 6px; }
.markdown-body a { color: var(--drac-pink); text-decoration: none; border-bottom: 1px dashed var(--drac-pink); }
.markdown-body table { width: 100%; border-collapse: collapse; margin: 24px 0; background: var(--bg-card); border-radius: 8px; overflow: hidden; font-size: 0.95rem; }
.markdown-body th, .markdown-body td { padding: 14px 16px; border-bottom: 1px solid var(--bg-main); text-align: left; }
.markdown-body th { color: var(--drac-yellow); font-weight: 600; background: rgba(33, 34, 44, 0.6); }
.markdown-body strong { color: var(--drac-orange); font-weight: 600; }
.markdown-body code { background: var(--bg-code); padding: 2px 6px; border-radius: 4px; font-family: var(--font-mono); font-size: 0.85em; color: var(--drac-green); }

.code-wrapper { position: relative; margin-bottom: 20px; width: 100%; }
.markdown-body pre { background: var(--bg-code); padding: 16px; border-radius: 8px; overflow-x: auto; border: 1px solid var(--border-color); margin: 0; font-family: var(--font-mono); font-size: 0.9rem; max-width: 100%; }
.markdown-body pre code { background: transparent; padding: 0; color: inherit; }
.btn-copy-code { position: absolute; top: 8px; right: 8px; background: var(--bg-card); border: 1px solid var(--border-color); color: var(--drac-comment); border-radius: 4px; padding: 6px 12px; font-size: 0.75rem; cursor: pointer; transition: 0.2s; opacity: 0; }
.code-wrapper:hover .btn-copy-code { opacity: 1; }
.btn-copy-code:hover { background: var(--drac-purple); color: var(--bg-main); }

/* TOC */
.toc-sidebar { width: 240px; position: sticky; top: 90px; flex-shrink: 0; background: var(--bg-card); border: 1px solid var(--border-color); border-radius: 8px; padding: 20px; }
.toc-header { font-family: var(--font-mono); font-size: 0.7rem; color: var(--drac-comment); margin-bottom: 16px; text-transform: uppercase; font-weight: 700; }
.toc-content ul { list-style: none; padding: 0; }
.toc-content li { margin-bottom: 10px; }
.toc-content a { color: var(--text-main); text-decoration: none; font-size: 0.85rem; transition: 0.2s; display: block; opacity: 0.8; }
.toc-content a:hover { opacity: 1; color: var(--drac-cyan); transform: translateX(4px); }
.toc-h3 { padding-left: 14px; font-size: 0.75rem; color: var(--drac-comment); }

/* QUIZ UI (EPHEMERAL) */
.quiz-container { background: rgba(68, 71, 90, 0.2); border: 1px solid var(--border-color); border-radius: 10px; padding: 24px; margin-top: 40px; transition: all 0.5s ease; overflow: hidden; }
.quiz-container.fade-out { opacity: 0; transform: scale(0.95) translateY(-10px); }
.quiz-title { display: flex; align-items: center; gap: 10px; color: var(--drac-yellow); font-size: 1.2rem; margin-bottom: 20px; border-bottom: 1px solid var(--border-color); padding-bottom: 12px; font-weight: 600; }
.quiz-question { font-weight: 500; margin-bottom: 16px; font-size: 1.05rem; }
.quiz-options { display: flex; flex-direction: column; gap: 10px; }
.quiz-option { background: var(--bg-code); border: 1px solid var(--border-color); padding: 12px 16px; border-radius: 8px; cursor: pointer; transition: 0.2s; display: flex; align-items: center; gap: 12px; font-size: 0.95rem; }
.quiz-option:hover { border-color: var(--drac-purple); }
.quiz-option input { display: none; }
.quiz-option .radio-custom { width: 18px; height: 18px; border: 2px solid var(--drac-comment); border-radius: 50%; position: relative; flex-shrink: 0; }
.quiz-option input:checked + .radio-custom::after { content: ''; position: absolute; top: 3px; left: 3px; width: 8px; height: 8px; background: var(--drac-cyan); border-radius: 50%; }
.quiz-option input:checked + .radio-custom { border-color: var(--drac-cyan); }
.quiz-submit { background: transparent; border: 1px solid var(--drac-cyan); color: var(--drac-cyan); padding: 8px 20px; border-radius: 6px; cursor: pointer; margin-top: 20px; font-family: var(--font-mono); font-size: 0.85rem; font-weight: 600; transition: 0.2s; }
.quiz-submit:hover { background: var(--drac-cyan); color: var(--bg-main); }
.quiz-locked .quiz-option { cursor: default; opacity: 0.6; }
.quiz-locked .quiz-option.correct { border-color: var(--drac-green); background: rgba(80, 250, 123, 0.1); opacity: 1; }
.quiz-locked .quiz-option.incorrect { border-color: var(--drac-red); background: rgba(255, 85, 85, 0.1); }
.quiz-feedback { margin-top: 16px; font-size: 0.95rem; font-weight: 600; display: flex; justify-content: space-between; align-items: center; padding: 12px 16px; border-radius: 6px; }
.quiz-feedback.success { background: rgba(80, 250, 123, 0.1); color: var(--drac-green); border: 1px solid var(--drac-green); }
.quiz-feedback.error { background: rgba(255, 85, 85, 0.1); color: var(--drac-red); border: 1px solid var(--drac-red); }
.quiz-timer { font-family: var(--font-mono); font-size: 0.8rem; opacity: 0.8; }

/* LESSON FOOTER & NEXT MODULE */
.lesson-footer { margin-top: auto; padding-top: 40px; padding-bottom: 20px; display: flex; flex-direction: column; gap: 24px; }
.complete-btn { align-self: flex-start; background: transparent; border: 1px solid var(--drac-green); color: var(--drac-green); padding: 10px 20px; border-radius: 8px; font-size: 0.9rem; font-weight: 600; cursor: pointer; display: flex; align-items: center; gap: 8px; transition: 0.2s; }
.complete-btn:hover { background: rgba(80, 250, 123, 0.1); }
.complete-btn.is-completed { background: var(--drac-green); color: var(--bg-main); }

.next-module-box { background: var(--bg-card); border: 1px solid var(--drac-purple); border-radius: 12px; padding: 24px; display: flex; flex-direction: column; align-items: flex-end; transition: transform 0.2s, box-shadow 0.2s; cursor: pointer; text-align: right; }
.next-module-box:hover { transform: translateY(-4px); box-shadow: var(--shadow-md); background: rgba(189, 147, 249, 0.1); }
.next-label { font-family: var(--font-mono); font-size: 0.75rem; color: var(--drac-comment); text-transform: uppercase; letter-spacing: 1px; margin-bottom: 8px; }
.next-btn { font-size: 1.4rem; font-weight: 700; color: var(--drac-cyan); display: flex; align-items: center; gap: 10px; }
.next-btn svg { transition: transform 0.2s; }
.next-module-box:hover .next-btn svg { transform: translateX(6px); }

/* RESPONSIVE */
.mobile-overlay { display: none; position: fixed; top: 0; left: 0; width: 100%; height: 100%; background: rgba(0,0,0,0.6); backdrop-filter: blur(4px); z-index: 90; opacity: 0; transition: opacity 0.3s; }
.mobile-overlay.active { display: block; opacity: 1; }
@media (max-width: 1100px) { .toc-sidebar { display: none; } }
@media (max-width: 900px) {
  .hover-trigger { display: none; }
  .sidebar { transform: translateX(-100%); }
  .sidebar.open { transform: translateX(0); }
  .main-content { padding-left: 0; }
  .breadcrumbs { display: none; }
  .lesson-viewer { padding: 24px 20px; }
  .lesson-header h2 { font-size: 1.8rem; }
}