/* ══════════════════════════════════════════════════════
   LIEC – Lecciones de Circuitos Eléctricos
   Diseño moderno con modo oscuro/claro
   ══════════════════════════════════════════════════════ */

/* ── Variables de tema ── */
:root {
  --accent: #3b82f6;
  --bg: #f8fafc;
  --bg2: #ffffff;
  --sidebar-bg: #1e293b;
  --sidebar-text: #cbd5e1;
  --sidebar-hover: rgba(255,255,255,0.08);
  --text: #1e293b;
  --text2: #475569;
  --border: #e2e8f0;
  --code-bg: #f1f5f9;
  --shadow: 0 1px 3px rgba(0,0,0,0.1), 0 1px 2px rgba(0,0,0,0.06);
  --shadow-lg: 0 10px 25px rgba(0,0,0,0.15);
  --radius: 0.75rem;
  --sidebar-w: 280px;
  --topbar-h: 56px;
  --transition: 0.2s ease;
}
[data-theme="dark"] {
  --bg: #0f172a;
  --bg2: #1e293b;
  --text: #e2e8f0;
  --text2: #94a3b8;
  --border: #334155;
  --code-bg: #1e293b;
}

/* ── Reset ── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { font-size: 16px; scroll-behavior: smooth; }
body {
  font-family: 'Inter', system-ui, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.7;
  transition: background var(--transition), color var(--transition);
}
a { color: var(--accent); text-decoration: none; transition: opacity var(--transition); }
a:hover { opacity: 0.75; }
img { max-width: 100%; height: auto; border-radius: 0.5rem; }

/* ── Layout ── */
.layout { display: flex; min-height: 100vh; }

/* ── Sidebar ── */
.sidebar {
  width: var(--sidebar-w);
  min-width: var(--sidebar-w);
  background: var(--sidebar-bg);
  color: var(--sidebar-text);
  display: flex;
  flex-direction: column;
  height: 100vh;
  position: sticky;
  top: 0;
  overflow-y: auto;
  overflow-x: hidden;
  z-index: 200;
  scrollbar-width: thin;
  scrollbar-color: rgba(255,255,255,0.15) transparent;
  transition: transform var(--transition);
}
.sidebar-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1.25rem 1rem;
  border-bottom: 1px solid rgba(255,255,255,0.08);
  flex-shrink: 0;
}
.logo {
  font-size: 1.3rem;
  font-weight: 700;
  color: #fff;
  letter-spacing: -0.02em;
}
.sidebar-close {
  display: none;
  background: none;
  border: none;
  color: var(--sidebar-text);
  font-size: 1.2rem;
  cursor: pointer;
  padding: 0.25rem;
}

/* ── Search box ── */
.search-box {
  padding: 0.75rem 1rem;
  border-bottom: 1px solid rgba(255,255,255,0.08);
  position: relative;
  flex-shrink: 0;
}
#search-input {
  width: 100%;
  padding: 0.5rem 0.75rem;
  background: rgba(255,255,255,0.08);
  border: 1px solid rgba(255,255,255,0.12);
  border-radius: 0.5rem;
  color: #fff;
  font-size: 0.85rem;
  outline: none;
  transition: border-color var(--transition);
}
#search-input::placeholder { color: rgba(255,255,255,0.4); }
#search-input:focus { border-color: var(--accent); }
.search-results {
  position: absolute;
  left: 1rem; right: 1rem;
  top: calc(100% - 0.25rem);
  background: var(--bg2);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow-lg);
  z-index: 300;
  max-height: 320px;
  overflow-y: auto;
}
.search-results.hidden { display: none; }
.search-result-item {
  padding: 0.6rem 0.9rem;
  border-bottom: 1px solid var(--border);
  cursor: pointer;
  color: var(--text);
}
.search-result-item:hover { background: var(--bg); }
.search-result-item strong { display: block; font-size: 0.88rem; color: var(--accent); }
.search-result-item span { font-size: 0.78rem; color: var(--text2); }

/* ── Sidebar Navigation ── */
.sidebar-nav { padding: 0.5rem 0 2rem; overflow-y: auto; flex: 1; }
.vol-group { margin-bottom: 0.25rem; }
.vol-title {
  display: block;
  padding: 0.65rem 1rem;
  font-size: 0.82rem;
  font-weight: 600;
  color: #fff;
  border-left: 3px solid var(--vc, #3b82f6);
  background: rgba(255,255,255,0.04);
  letter-spacing: 0.02em;
  text-transform: uppercase;
  transition: background var(--transition);
}
.vol-title:hover { background: var(--sidebar-hover); opacity: 1; }
.cap-list { list-style: none; }
.cap-list li a {
  display: block;
  padding: 0.45rem 1rem 0.45rem 1.75rem;
  font-size: 0.82rem;
  color: var(--sidebar-text);
  border-radius: 0;
  transition: background var(--transition), color var(--transition);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.cap-list li a:hover { background: var(--sidebar-hover); color: #fff; opacity: 1; }
.cap-list li a.active { color: var(--accent); font-weight: 600; }

/* Overlay sidebar móvil */
.sidebar-overlay {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.5);
  z-index: 150;
}

/* ── Main content ── */
.main-content {
  flex: 1;
  min-width: 0;
  display: flex;
  flex-direction: column;
}

/* ── Top bar ── */
.top-bar {
  height: var(--topbar-h);
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 0 1.5rem;
  background: var(--bg2);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: var(--shadow);
}
.menu-btn, .theme-btn {
  background: none;
  border: 1px solid var(--border);
  border-radius: 0.5rem;
  padding: 0.35rem 0.6rem;
  cursor: pointer;
  font-size: 1rem;
  color: var(--text);
  transition: background var(--transition);
  flex-shrink: 0;
}
.menu-btn:hover, .theme-btn:hover { background: var(--bg); }
.menu-btn { display: none; }
.page-title {
  flex: 1;
  font-size: 0.92rem;
  font-weight: 600;
  color: var(--text2);
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

/* ── Content area ── */
.content {
  max-width: 860px;
  margin: 0 auto;
  padding: 2rem 2rem 3rem;
  width: 100%;
}
.content h1 { font-size: 2rem; font-weight: 700; margin: 1.5rem 0 0.75rem; line-height: 1.25; }
.content h2 { font-size: 1.4rem; font-weight: 600; margin: 2rem 0 0.75rem; padding-bottom: 0.4rem; border-bottom: 2px solid var(--border); }
.content h3 { font-size: 1.15rem; font-weight: 600; margin: 1.5rem 0 0.5rem; }
.content h4, .content h5 { font-size: 1rem; font-weight: 600; margin: 1.25rem 0 0.4rem; }
.content p { margin-bottom: 1rem; }
.content ul, .content ol { padding-left: 1.75rem; margin-bottom: 1rem; }
.content li { margin-bottom: 0.35rem; }
.content blockquote {
  border-left: 4px solid var(--accent);
  margin: 1.25rem 0;
  padding: 0.75rem 1.25rem;
  background: var(--code-bg);
  border-radius: 0 var(--radius) var(--radius) 0;
  font-style: italic;
  color: var(--text2);
}
.content table {
  width: 100%;
  border-collapse: collapse;
  margin: 1.25rem 0;
  font-size: 0.9rem;
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: var(--shadow);
}
.content th {
  background: var(--accent);
  color: #fff;
  padding: 0.65rem 0.9rem;
  text-align: left;
  font-weight: 600;
}
.content td {
  padding: 0.55rem 0.9rem;
  border-bottom: 1px solid var(--border);
}
.content tr:nth-child(even) td { background: var(--code-bg); }
.content pre, .content code {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.85rem;
  background: var(--code-bg);
  border-radius: 0.4rem;
}
.content pre {
  padding: 1.1rem 1.25rem;
  overflow-x: auto;
  margin: 1rem 0;
  border: 1px solid var(--border);
}
.content code { padding: 0.15rem 0.4rem; }
.content pre code { background: none; padding: 0; }
.content hr { border: none; border-top: 2px solid var(--border); margin: 2rem 0; }
.content img {
  display: block;
  margin: 1.25rem auto;
  box-shadow: var(--shadow);
}

/* ── REVIEW boxes ── */
.content ul li b:first-child { color: var(--accent); }

/* ── Chapter nav (prev/next) ── */
.chapter-nav {
  display: flex;
  gap: 0.75rem;
  align-items: center;
  justify-content: center;
  padding: 1.5rem 2rem;
  border-top: 1px solid var(--border);
  flex-wrap: wrap;
}
.nav-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.55rem 1.25rem;
  background: var(--accent);
  color: #fff;
  border-radius: var(--radius);
  font-size: 0.88rem;
  font-weight: 500;
  transition: opacity var(--transition), transform var(--transition);
  box-shadow: var(--shadow);
}
.nav-btn:hover { opacity: 0.85; transform: translateY(-1px); }
.nav-home { background: var(--text2); }

/* ── Footer ── */
.site-footer {
  padding: 1.5rem 2rem;
  text-align: center;
  font-size: 0.8rem;
  color: var(--text2);
  border-top: 1px solid var(--border);
  margin-top: auto;
}
.site-footer a { color: var(--accent); }

/* ── Home page ── */
.hero {
  text-align: center;
  padding: 3rem 1rem 2rem;
}
.hero h1 { font-size: 2.5rem; margin-bottom: 0.75rem; }
.hero-sub { font-size: 1.1rem; color: var(--text2); margin-bottom: 0.5rem; }
.hero-author { font-size: 0.9rem; color: var(--text2); }
.volumes-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 1.25rem;
  margin-top: 2rem;
}
.vol-card {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.5rem;
  padding: 2rem 1.5rem;
  background: var(--bg2);
  border: 2px solid var(--border);
  border-radius: var(--radius);
  color: var(--text);
  text-align: center;
  transition: transform var(--transition), box-shadow var(--transition), border-color var(--transition);
  box-shadow: var(--shadow);
}
.vol-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
  border-color: var(--c, var(--accent));
  opacity: 1;
}
.vol-icon { font-size: 2.5rem; }
.vol-card h2 { font-size: 1.1rem; margin: 0; color: var(--c, var(--accent)); }
.vol-card p { font-size: 0.88rem; color: var(--text2); margin: 0; }

/* ── Responsive ── */
@media (max-width: 900px) {
  .sidebar {
    position: fixed;
    top: 0; left: 0; height: 100%;
    transform: translateX(-100%);
  }
  .sidebar.open { transform: translateX(0); }
  .sidebar-overlay.open { display: block; }
  .sidebar-close { display: block; }
  .menu-btn { display: flex; }
  .content { padding: 1.25rem 1rem 2rem; }
}
@media (max-width: 480px) {
  .hero h1 { font-size: 1.75rem; }
  .chapter-nav { flex-direction: column; }
}