/* ──── LAYOUT ──── */
.shell { display: flex; min-height: 100vh; }

/* ──── SIDEBAR ──── */
.sidebar {
  width: 280px;
  flex-shrink: 0;
  background: var(--bg2);
  border-right: 1px solid var(--border);
  position: fixed;
  top: 0; left: 0; bottom: 0;
  overflow-y: auto;
  z-index: 100;
  display: flex;
  flex-direction: column;
}

.sidebar-logo {
  padding: 28px 24px 20px;
  border-bottom: 1px solid var(--border);
}
.sidebar-logo .logo-badge {
  display: inline-block;
  background: var(--accent-bg);
  border: 1px solid var(--accent-border);
  color: var(--accent2);
  font-family: var(--font-mono);
  font-size: 10px;
  padding: 3px 8px;
  border-radius: 4px;
  letter-spacing: 0.08em;
  margin-bottom: 10px;
}
.sidebar-logo h1 {
  font-family: var(--font-display);
  font-size: 22px;
  font-weight:650;
  letter-spacing:-0.015em;
  color: var(--text);
  line-height: 1.1;
}
.sidebar-logo p {
  font-size: 12px;
  color: var(--text3);
  margin-top: 4px;
}

.progress-wrap {
  padding: 16px 24px;
  border-bottom: 1px solid var(--border);
}
.progress-label {
  display: flex;
  justify-content: space-between;
  font-size: 11px;
  color: var(--text3);
  margin-bottom: 8px;
  font-family: var(--font-mono);
}
.progress-bar {
  height: 3px;
  background: var(--bg4);
  border-radius: 2px;
  overflow: hidden;
}
.progress-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--accent), var(--teal));
  border-radius: 2px;
  transition: width 0.4s ease;
  width: 0%;
}

.nav-section {
  padding: 20px 16px 8px;
}
.nav-section-title {
  font-size: 10px;
  font-family: var(--font-mono);
  color: var(--text3);
  letter-spacing: 0.12em;
  text-transform: uppercase;
  padding: 0 8px;
  margin-bottom: 6px;
}

.nav-item {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 9px 12px;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: all 0.15s;
  border: none;
  background: none;
  width: 100%;
  text-align: left;
  color: var(--text2);
  font-family: var(--font);
  font-size: 13px;
  position: relative;
}
.nav-item:hover { background: var(--bg3); color: var(--text); }
.nav-item.active {
  background: var(--accent-bg);
  color: var(--accent2);
  border: 1px solid var(--accent-border);
}
.nav-item .nav-icon { font-size: 14px; min-width: 18px; text-align: center; }
.nav-item .nav-check {
  margin-left: auto;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  border: 1.5px solid var(--text3);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 9px;
  flex-shrink: 0;
  transition: all 0.2s;
}
.nav-item.done .nav-check {
  background: var(--green);
  border-color: var(--green);
  color: #000;
}

.sidebar-footer {
  margin-top: auto;
  padding: 16px 24px;
  border-top: 1px solid var(--border);
  font-size: 11px;
  color: var(--text3);
}

/* ──── MAIN CONTENT ──── */
.main {
  margin-left: 280px;
  flex: 1;
  min-height: 100vh;
  min-width: 0;
  overflow-x: hidden;
}

.topbar {
  position: sticky;
  top: 0;
  background: rgba(255,255,255,0.92);
  backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border);
  box-shadow: 0 1px 0 rgba(26,86,232,0.06), 0 4px 20px rgba(26,86,232,0.04);
  padding: 14px 48px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  z-index: 50;
}
.topbar-breadcrumb {
  font-size: 13px;
  color: var(--text3);
  font-family: var(--font-mono);
}
.topbar-breadcrumb span { color: var(--text2); }

.topbar-actions { display: flex; gap: 10px; }
.btn {
  padding: 8px 18px;
  border-radius: var(--radius-sm);
  font-family: var(--font);
  font-size: 13px;
  cursor: pointer;
  border: none;
  transition: all 0.15s;
}
.btn-ghost {
  background: var(--bg3);
  border: 1px solid var(--border2);
  color: var(--text2);
}
.btn-ghost:hover { color: var(--text); border-color: var(--border2); background: var(--bg4); }
.btn-primary {
  background: var(--accent);
  color: #fff;
  font-weight: 500;
}
.btn-primary:hover { background: #7c75ff; }

/* ──── LESSON PAGES ──── */
.lesson { display: none; padding: 48px 48px 80px; max-width: 860px; min-width: 0; word-break: break-word; }
.lesson.active { display: block; animation: fadeIn 0.3s ease; }

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(8px); }
  to { opacity: 1; transform: translateY(0); }
}

.lesson-header {
  margin-bottom: 40px;
  padding-bottom: 32px;
  border-bottom: 1px solid var(--border);
}
.lesson-tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 11px;
  font-family: var(--font-mono);
  color: var(--accent2);
  background: var(--accent-bg);
  border: 1px solid var(--accent-border);
  padding: 4px 10px;
  border-radius: 4px;
  margin-bottom: 16px;
  letter-spacing: 0.06em;
}
.lesson h1 {
  font-family: var(--font-display);
  font-size: 48px;
  font-weight:650;
  line-height: 1;
  letter-spacing:-0.015em;
  margin-bottom: 12px;
  background: linear-gradient(105deg, var(--ink) 0%, var(--ink) 28%, var(--accent) 44%, #a8c0ff 52%, var(--accent) 60%, var(--ink) 100%);
  background-size: 250% 100%;
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  animation: shine 4s ease-in-out infinite;
}
@keyframes shine {
  0%   { background-position: 100% 50%; }
  50%  { background-position: 0% 50%; }
  100% { background-position: 100% 50%; }
}
.lesson-intro {
  font-size: 16px;
  color: var(--text2);
  line-height: 1.75;
  max-width: 680px;
}

/* ──── CONTENT ELEMENTS ──── */
h2.section-title {
  font-family: var(--font-display);
  font-size: 28px;
  font-weight:650;
  letter-spacing:-0.015em;
  margin: 40px 0 16px;
  color: var(--text);
  display: flex;
  align-items: center;
  gap: 10px;
}
h2.section-title::before {
  content: '';
  display: block;
  width: 4px;
  height: 22px;
  background: linear-gradient(var(--accent), var(--teal));
  border-radius: 2px;
  flex-shrink: 0;
}

h3.sub-title {
  font-family: var(--font-display);
  font-size: 22px;
  font-weight:650;
  letter-spacing:-0.015em;
  margin: 28px 0 10px;
  color: var(--text);
}

p.body-text {
  font-size: 15px;
  color: var(--text2);
  line-height: 1.8;
  margin-bottom: 16px;
}

/* Cards */
.card {
  background: var(--bg2);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  margin-bottom: 16px;
  transition: border-color 0.2s;
}
.card:hover { border-color: var(--border2); }

.card-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; margin-bottom: 16px; }
.card-grid-3 { display: grid; grid-template-columns: 1fr 1fr 1fr; gap: 12px; margin-bottom: 16px; }
@media (max-width: 700px) { .card-grid, .card-grid-3 { grid-template-columns: 1fr; } }

.card-icon { font-size: 28px; margin-bottom: 10px; }
.card h4 { font-family: var(--font-display); font-size: 18px; font-weight:650; letter-spacing:-0.015em; margin-bottom: 6px; color: var(--text); }
.card p { font-size: 13px; color: var(--text2); line-height: 1.6; }

/* Callouts */
.callout {
  display: flex;
  gap: 14px;
  padding: 16px 20px;
  border-radius: var(--radius-sm);
  margin: 20px 0;
  font-size: 14px;
  line-height: 1.65;
  border-left: 3px solid;
}
.callout-icon { font-size: 18px; flex-shrink: 0; margin-top: 1px; }
.callout-content { flex: 1; }
.callout-content strong { display: block; font-weight: 500; margin-bottom: 3px; }
.callout-content p { margin: 0; }

.callout-blue { background: rgba(26,86,232,0.07); border-color: var(--accent); }
.callout-blue .callout-icon { color: var(--accent); }
.callout-blue .callout-content { color: #1e3a8a; }
.callout-blue .callout-content strong { color: var(--accent); }
.callout-green { background: rgba(22,163,74,0.07); border-color: var(--green); }
.callout-green .callout-icon { color: #15803d; }
.callout-green .callout-content { color: #14532d; }
.callout-green .callout-content strong { color: #16a34a; }
.callout-amber { background: rgba(217,119,6,0.07); border-color: var(--amber); }
.callout-amber .callout-icon { color: #b45309; }
.callout-amber .callout-content { color: #78350f; }
.callout-amber .callout-content strong { color: #d97706; }
.callout-coral { background: rgba(220,38,38,0.07); border-color: var(--coral); }
.callout-coral .callout-icon { color: #dc2626; }
.callout-coral .callout-content { color: #7f1d1d; }
.callout-coral .callout-content strong { color: #dc2626; }

/* Code blocks */
.code-wrap { margin: 20px 0; border-radius: var(--radius-sm); overflow: hidden; border: 1px solid var(--border2); }
.code-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: #091228;
  padding: 10px 16px;
  border-bottom: 1px solid rgba(168,192,255,0.1);
}
.code-label { font-family: var(--font-mono); font-size: 11px; color: var(--text3); }
.code-dots { display: flex; gap: 5px; }
.code-dot { width: 8px; height: 8px; border-radius: 50%; }
.d1 { background: #ff5f57; }
.d2 { background: #febc2e; }
.d3 { background: #28c840; }
pre {
  background: var(--ink);
  padding: 20px;
  overflow-x: auto;
  font-family: var(--font-mono);
  font-size: 13px;
  line-height: 1.7;
  color: #c8d8ff;
  margin: 0;
}
.c-purple { color: #c792ea; }
.c-green { color: #c3e88d; }
.c-blue { color: #82aaff; }
.c-orange { color: #ffcb6b; }
.c-gray { color: #637777; }
.c-teal { color: #2dd4bf; }
.c-red { color: #f87171; }
.c-white { color: #eeffff; }

/* Steps */
.steps { margin: 20px 0; }
.step {
  display: flex;
  gap: 16px;
  margin-bottom: 20px;
  align-items: flex-start;
}
.step-num {
  width: 32px;
  height: 32px;
  border-radius: 50%;
  background: var(--accent-bg);
  border: 1px solid var(--accent-border);
  color: var(--accent2);
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 500;
  flex-shrink: 0;
  margin-top: 2px;
}
.step-body { flex: 1; }
.step-body strong { display: block; font-size: 15px; font-weight: 500; color: var(--text); margin-bottom: 4px; }
.step-body span, .step-body p { font-size: 14px; color: var(--text2); line-height: 1.65; }

/* Tags/badges */
.badge {
  display: inline-block;
  font-size: 11px;
  font-family: var(--font-mono);
  padding: 3px 10px;
  border-radius: 4px;
  font-weight: 500;
  margin: 2px;
}
.badge-purple { background: var(--accent-bg); color: var(--accent2); border: 1px solid var(--accent-border); }
.badge-green { background: var(--green-bg); color: var(--green); border: 1px solid rgba(34,197,94,0.25); }
.badge-amber { background: var(--amber-bg); color: var(--amber); border: 1px solid rgba(245,158,11,0.25); }
.badge-teal { background: var(--teal-bg); color: var(--teal); border: 1px solid rgba(45,212,191,0.25); }
.badge-coral { background: var(--coral-bg); color: var(--coral); border: 1px solid rgba(248,113,113,0.25); }

/* Tool cards */
.tool-card {
  background: var(--bg2);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px 24px;
  margin-bottom: 12px;
  cursor: pointer;
  transition: all 0.2s;
}
.tool-card:hover { border-color: var(--border2); background: var(--bg3); }
.tool-card.expanded { border-color: var(--accent-border); background: var(--bg3); }

.tool-card-header {
  display: flex;
  align-items: center;
  gap: 12px;
}
.tool-emoji { font-size: 22px; }
.tool-name { font-family: var(--font-display); font-size: 20px; font-weight:650; letter-spacing:-0.015em; color: var(--text); }
.tool-tagline { font-size: 13px; color: var(--text3); margin-top: 2px; }
.tool-expand { margin-left: auto; color: var(--text3); font-size: 18px; transition: transform 0.2s; }
.tool-card.expanded .tool-expand { transform: rotate(45deg); }
.tool-body { display: none; margin-top: 20px; padding-top: 20px; border-top: 1px solid var(--border); }
.tool-card.expanded .tool-body { display: block; }

/* Diagram SVGs */
.diagram-wrap {
  background: var(--bg2);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  margin: 24px 0;
  overflow: hidden;
}
.diagram-title {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--text3);
  letter-spacing: 0.08em;
  margin-bottom: 16px;
  text-transform: uppercase;
}

/* Concept comparison */
.compare-row {
  display: grid;
  grid-template-columns: 1fr 1fr 1fr;
  gap: 12px;
  margin: 20px 0;
}
.compare-cell {
  background: var(--bg3);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 16px;
  text-align: center;
}
.compare-cell .icon { font-size: 28px; margin-bottom: 8px; }
.compare-cell h5 { font-family: var(--font-display); font-size: 17px; font-weight:650; letter-spacing:-0.015em; color: var(--text); margin-bottom: 4px; }
.compare-cell p { font-size: 12px; color: var(--text2); line-height: 1.5; }
.compare-cell .meta { font-family: var(--font-mono); font-size: 10px; color: var(--text3); margin-top: 8px; }

/* Checklist */
.checklist { list-style: none; margin: 16px 0; }
.checklist li {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  padding: 8px 0;
  border-bottom: 1px solid var(--border);
  font-size: 14px;
  color: var(--text2);
  line-height: 1.5;
}
.checklist li:last-child { border-bottom: none; }
.checklist li::before {
  content: '◈';
  color: var(--accent2);
  font-size: 12px;
  margin-top: 3px;
  flex-shrink: 0;
}

/* Flow diagram inline */
.flow-inline {
  display: flex;
  align-items: center;
  gap: 0;
  flex-wrap: wrap;
  margin: 20px 0;
}
.flow-node {
  background: var(--bg3);
  border: 1px solid var(--border2);
  border-radius: var(--radius-sm);
  padding: 10px 16px;
  font-size: 13px;
  font-weight: 500;
  color: var(--text);
  white-space: nowrap;
}
.flow-arrow {
  color: var(--text3);
  font-size: 18px;
  padding: 0 8px;
  flex-shrink: 0;
}
.flow-node.accent { background: var(--accent-bg); border-color: var(--accent-border); color: var(--accent2); }
.flow-node.green { background: var(--green-bg); border-color: rgba(34,197,94,0.25); color: var(--green); }
.flow-node.teal { background: var(--teal-bg); border-color: rgba(45,212,191,0.25); color: var(--teal); }
.flow-node.amber { background: var(--amber-bg); border-color: rgba(245,158,11,0.25); color: var(--amber); }

/* Quiz section */
.quiz-card {
  background: var(--bg2);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  margin: 28px 0;
}
.quiz-card h4 { font-family: var(--font-display); font-size: 20px; font-weight:650; letter-spacing:-0.015em; margin-bottom: 16px; }
.quiz-options { display: flex; flex-direction: column; gap: 8px; }
.quiz-opt {
  padding: 12px 16px;
  border: 1px solid var(--border2);
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-size: 14px;
  color: var(--text2);
  transition: all 0.15s;
  background: var(--bg3);
}
.quiz-opt:hover { border-color: var(--accent-border); color: var(--accent2); }
.quiz-opt.correct { border-color: var(--green); color: var(--green); background: var(--green-bg); }
.quiz-opt.wrong { border-color: var(--coral); color: var(--coral); background: var(--coral-bg); }
.quiz-feedback { margin-top: 12px; font-size: 13px; color: var(--text3); display: none; }
.quiz-feedback.show { display: block; }

/* Lesson nav */
.lesson-nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-top: 60px;
  padding-top: 32px;
  border-top: 1px solid var(--border);
}

/* ──── HERO / HOME ──── */
.hero-lesson {
  padding: 80px 48px;
  max-width: 860px;
}
.hero-eyebrow {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--accent2);
  letter-spacing: 0.12em;
  text-transform: uppercase;
  margin-bottom: 20px;
}
.hero-lesson h1 {
  font-family: var(--font-display);
  font-size: 72px;
  font-weight:650;
  line-height: 0.95;
  letter-spacing:-0.015em;
  margin-bottom: 20px;
  background: linear-gradient(105deg, var(--ink) 0%, var(--ink) 25%, var(--accent) 42%, #a8c0ff 52%, var(--accent) 62%, var(--ink) 100%);
  background-size: 250% 100%;
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  animation: shine 4s ease-in-out infinite;
}
.hero-lesson .subtitle {
  font-size: 18px;
  color: var(--text2);
  line-height: 1.7;
  max-width: 600px;
  margin-bottom: 40px;
}
.tools-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(130px, 1fr));
  gap: 10px;
  margin: 32px 0;
}
.tool-pill {
  background: var(--bg3);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 10px 14px;
  font-size: 12px;
  font-weight: 500;
  color: var(--text2);
  display: flex;
  align-items: center;
  gap: 8px;
  transition: all 0.15s;
}
.tool-pill:hover { border-color: var(--border2); color: var(--text); }

.modules-overview { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; margin-top: 40px; }
.mod-card {
  background: var(--bg2);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
  cursor: pointer;
  transition: all 0.2s;
}
.mod-card:hover { border-color: var(--accent-border); background: var(--bg3); }
.mod-num { font-family: var(--font-mono); font-size: 11px; color: var(--text3); margin-bottom: 6px; }
.mod-card h3 { font-family: var(--font-display); font-size: 18px; font-weight:650; letter-spacing:-0.015em; color: var(--text); margin-bottom: 4px; }
.mod-card p { font-size: 12px; color: var(--text3); }
.mod-count { font-family: var(--font-mono); font-size: 10px; color: var(--accent2); margin-top: 10px; }

/* ──── ANIMACIONES EXTRA ──── */

/* Progress bar shimmer */
.progress-fill {
  background: linear-gradient(90deg, var(--accent) 0%, #a8c0ff 50%, var(--accent) 100%);
  background-size: 200% 100%;
  animation: progressShimmer 2.5s linear infinite;
}
@keyframes progressShimmer {
  0%   { background-position: 200% center; }
  100% { background-position: -200% center; }
}

/* Card hover lift */
.card {
  transition: all 0.3s cubic-bezier(0.34, 1.56, 0.64, 1);
}
.card:hover {
  transform: translateY(-5px);
  box-shadow: 0 16px 48px rgba(26,86,232,0.13);
  border-color: var(--accent-border);
}

/* Mod card hover */
.mod-card {
  transition: all 0.3s cubic-bezier(0.34, 1.56, 0.64, 1);
}
.mod-card:hover {
  transform: translateY(-6px);
  box-shadow: 0 20px 60px rgba(26,86,232,0.14);
  border-color: var(--accent-border);
  background: var(--bg3);
}

/* Tool pill hover float */
.tool-pill {
  transition: all 0.25s cubic-bezier(0.34, 1.56, 0.64, 1);
}
.tool-pill:hover {
  transform: translateY(-4px) scale(1.04);
  box-shadow: 0 8px 24px rgba(26,86,232,0.18);
  border-color: var(--accent-border);
  color: var(--accent);
  background: var(--accent-bg);
}

/* Step number pulse on hover */
.step { transition: all 0.2s; }
.step:hover .step-num {
  animation: stepPulse 0.5s ease;
  border-color: var(--accent);
  color: var(--accent);
}
@keyframes stepPulse {
  0%, 100% { transform: scale(1); }
  50% { transform: scale(1.18); box-shadow: 0 0 0 6px rgba(26,86,232,0.12); }
}

/* Lesson fade + rise */
.lesson.active { animation: lessonIn 0.4s cubic-bezier(0.22, 1, 0.36, 1); }
@keyframes lessonIn {
  from { opacity: 0; transform: translateY(20px); }
  to   { opacity: 1; transform: translateY(0); }
}

/* Section title bar grow */
@keyframes barGrow {
  from { height: 0; opacity: 0; }
  to   { height: 22px; opacity: 1; }
}
h2.section-title::before { animation: barGrow 0.5s cubic-bezier(0.34, 1.56, 0.64, 1) both; }

/* Stagger entrance via JS class */
.anim-enter {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.5s ease, transform 0.5s cubic-bezier(0.34, 1.56, 0.64, 1);
}
.anim-enter.visible {
  opacity: 1;
  transform: translateY(0);
}

/* Tool card expand animation */
.tool-body { animation: none; }
.tool-card.expanded .tool-body {
  display: block;
  animation: bodyOpen 0.3s ease;
}
@keyframes bodyOpen {
  from { opacity: 0; transform: translateY(-8px); }
  to   { opacity: 1; transform: translateY(0); }
}

/* Callout slide-in */
.callout { animation: calloutIn 0.4s cubic-bezier(0.34, 1.56, 0.64, 1) both; }
@keyframes calloutIn {
  from { opacity: 0; transform: translateX(-12px); }
  to   { opacity: 1; transform: translateX(0); }
}

/* Button interactions */
.btn { transition: all 0.18s cubic-bezier(0.34, 1.56, 0.64, 1); }
.btn:hover { transform: translateY(-2px); }
.btn:active { transform: scale(0.95); }
.btn-primary:hover { background: var(--accent-hover); box-shadow: 0 8px 24px rgba(26,86,232,0.3); }
.btn-ghost:hover { color: var(--text); border-color: var(--accent-border); background: var(--accent-bg); }

/* Nav item active indicator */
.nav-item { transition: all 0.2s; }
.nav-item.active {
  background: var(--accent-bg);
  color: var(--accent);
  border: 1px solid var(--accent-border);
  position: relative;
}
.nav-item.active::before {
  content: '';
  position: absolute;
  left: 0; top: 6px; bottom: 6px;
  width: 3px;
  background: var(--accent);
  border-radius: 2px;
  animation: navBar 0.3s cubic-bezier(0.34, 1.56, 0.64, 1);
}
@keyframes navBar {
  from { transform: scaleY(0); }
  to   { transform: scaleY(1); }
}

/* Checklist hover */
.checklist li { transition: all 0.2s; cursor: default; }
.checklist li:hover { color: var(--text); padding-left: 8px; }
.checklist li:hover::before { color: var(--accent); }

/* Flow node hover */
.flow-node { transition: all 0.2s cubic-bezier(0.34, 1.56, 0.64, 1); }
.flow-node:hover { transform: scale(1.06); }

/* Hero eyebrow blink cursor */
.hero-eyebrow::after {
  content: '|';
  animation: blink 1s step-end infinite;
  margin-left: 2px;
  color: var(--accent);
}
@keyframes blink {
  0%, 100% { opacity: 1; } 50% { opacity: 0; }
}

/* Quiz option hover */
.quiz-opt { transition: all 0.2s; }
.quiz-opt:hover { transform: translateX(4px); border-color: var(--accent-border); color: var(--accent); background: var(--accent-bg); }

/* Reset button */
.reset-btn {
  width: 100%;
  background: none;
  border: 1px solid var(--border2);
  color: var(--text3);
  font-size: 11px;
  font-family: var(--font-mono);
  padding: 8px 12px;
  border-radius: var(--radius-sm);
  cursor: pointer;
  margin-top: 10px;
  transition: all 0.2s;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  letter-spacing: 0.05em;
}
.reset-btn:hover {
  border-color: var(--coral);
  color: var(--coral);
  background: var(--coral-bg);
  transform: none;
}

/* SVG icon in nav */
.nav-icon { display: flex; align-items: center; width: 16px; flex-shrink: 0; }
.nav-icon svg { width: 15px; height: 15px; stroke: currentColor; fill: none; stroke-width: 1.8; stroke-linecap: round; stroke-linejoin: round; }

/* Tool pill SVG logo */
.pill-logo { width: 18px; height: 18px; flex-shrink: 0; }

/* Scrollbar */
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: var(--bg2); }
::-webkit-scrollbar-thumb { background: var(--border2); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: var(--accent-border); }

/* Responsive */
@media (max-width: 900px) {
  .sidebar { transform: translateX(-100%); transition: transform 0.3s; }
  .sidebar.open { transform: translateX(0); }
  .main { margin-left: 0; }
  .lesson, .hero-lesson { padding: 32px 24px 60px; }
  .topbar { padding: 12px 24px; }
  .hero-lesson h1 { font-size: 36px; }
  .modules-overview { grid-template-columns: 1fr; }
  .card-grid { grid-template-columns: 1fr; }
  .card-grid-3 { grid-template-columns: 1fr; }
  .compare-row { grid-template-columns: 1fr; }
}
.menu-btn {
  display: none;
  background: none;
  border: none;
  color: var(--text2);
  font-size: 20px;
  cursor: pointer;
  padding: 4px;
}
@media (max-width: 900px) { .menu-btn { display: block; } }

/* ── Course screen mobile (768px) ── */
@media (max-width: 768px) {
  .shell { flex-direction: column; }
  .sidebar {
    position: fixed; top: 0; left: -280px; bottom: 0; z-index: 200;
    transition: left 0.3s ease; width: 280px;
  }
  .sidebar.open { left: 0; box-shadow: 4px 0 24px rgba(0,0,0,0.2); }
  .main { margin-left: 0; width: 100%; min-width: 0; }
  .topbar { padding: 10px 14px; gap: 8px; flex-wrap: nowrap; }
  .topbar-breadcrumb { font-size: 11px; overflow: hidden; white-space: nowrap; text-overflow: ellipsis; max-width: 44vw; flex-shrink: 1; min-width: 0; }
  .topbar-actions { flex-shrink: 0; gap: 8px; }
  .topbar-actions .btn { padding: 8px 12px; font-size: 12px; white-space: nowrap; }
  .lesson { padding: 20px 14px 72px; max-width: 100%; }
  .hero-lesson { padding: 28px 14px 48px; max-width: 100%; }
  .hero-lesson h1 { font-size: clamp(22px, 7vw, 36px); }
  .lesson h1 { font-size: clamp(22px, 6vw, 34px); }
  .lesson h2 { font-size: clamp(18px, 5vw, 26px); }
  .modules-overview { grid-template-columns: 1fr; }
  .tools-grid { grid-template-columns: repeat(2, 1fr); }
  .diagram-wrap { overflow-x: auto; -webkit-overflow-scrolling: touch; padding: 16px 12px; }
  .diagram-wrap svg { min-width: 380px; max-width: none; display: block; }
  pre.code-block, .code-wrap { overflow-x: auto; -webkit-overflow-scrolling: touch; font-size: 12px; }
  .compare-grid { grid-template-columns: 1fr; }
  .cards-grid, .flow-grid { grid-template-columns: 1fr; }
  .card-grid { grid-template-columns: 1fr; }
  .card-grid-3 { grid-template-columns: 1fr; }
  .compare-row { grid-template-columns: 1fr; }
  h1 { font-size: clamp(22px, 6vw, 40px); }
  .quiz-card { padding: 16px 14px; }
  .quiz-opt { font-size: 13px; padding: 10px 12px; }
  .step { flex-direction: column; gap: 8px; }
  .step-num { align-self: flex-start; }
  .lesson-nav { flex-direction: column; gap: 10px; margin-top: 40px; padding-top: 24px; }
  .lesson-nav .btn { width: 100%; justify-content: center; }
  .callout { padding: 12px 14px; gap: 10px; }
  .tool-card-header { gap: 10px; }
  .tool-card-body { font-size: 13px; }
  /* Sidebar overlay backdrop */
  .sidebar-backdrop { display: none; position: fixed; inset: 0; z-index: 199; background: rgba(13,27,62,0.45); }
  .sidebar-backdrop.show { display: block; }
  /* Progress bar in sidebar */
  .sidebar { padding-bottom: 80px; }
  /* Tables */
  table { display: block; overflow-x: auto; -webkit-overflow-scrolling: touch; width: 100%; }
  /* Sidebar logo smaller */
  .sidebar-logo h1 { font-size: 18px; }
  .sidebar-logo { padding: 20px 16px 14px; }
  .nav-item { padding: 8px 16px; font-size: 13px; }
  /* Fix sidebar footer */
  .sidebar-footer { padding: 12px 16px; }
  /* Fix admin on mobile */
  .dash-main { padding: 16px; }
  .dash-welcome { flex-direction: column; gap: 16px; padding: 24px 16px; }
  .courses-grid { grid-template-columns: 1fr; }
  .course-card { min-width: 0; }
  .dash-nav { padding: 0 14px; height: 58px; }
  .dash-nav-brand { font-size: 18px; }
  .dash-nav-right { gap: 10px; }
  .dash-user-name, .dash-user-email { display: none; }
  .btn-signout { padding: 8px 12px; }
  .btn-signout-label { display: none; }
  .admin-screen { padding: 0; }
  .admin-topbar { padding: 12px 16px; }
  .admin-body { padding: 16px; }
  .admin-user-card { flex-wrap: wrap; }
}

@media (max-width: 480px) {
  .topbar { padding: 8px 10px; min-height: 52px; gap: 6px; }
  .topbar-breadcrumb { max-width: 38vw; font-size: 10px; }
  /* Course action buttons — compact icon+short text on mobile */
  .topbar-actions { gap: 6px; }
  .topbar-actions .btn { padding: 8px 10px; font-size: 11px; border-radius: 8px; }
  .topbar-actions .btn-ghost .btn-label-full { display: none; }
  .topbar-actions .btn-ghost .btn-label-short { display: inline; }
  .topbar-actions .btn-primary .btn-label-full { display: none; }
  .topbar-actions .btn-primary .btn-label-short { display: inline; }
  .lesson { padding: 16px 12px 72px; }
  .hero-lesson { padding: 20px 12px 40px; }
  .tools-grid { grid-template-columns: 1fr; }
  .diagram-wrap svg { min-width: 320px; }
  .lesson h1 { font-size: clamp(20px, 7vw, 28px); }
  .lesson h2 { font-size: clamp(16px, 5vw, 22px); }
  .lesson h3 { font-size: clamp(14px, 4.5vw, 18px); }
  .lesson-intro { font-size: 14px; }
  .body-text { font-size: 14px; }
  .lesson-nav .btn { font-size: 13px; padding: 10px 14px; }
  .card { padding: 16px 14px; }
  .card-icon { font-size: 24px; }
  pre.code-block { font-size: 11px; padding: 14px 12px; }
  .quiz-opt { font-size: 12px; }
  .btn { font-size: 13px; padding: 10px 16px; }
  .callout { flex-direction: column; gap: 6px; }
  .callout-icon { font-size: 16px; }
  .lesson-tag { font-size: 9px; }
  .lesson h1 { margin-top: 8px; }
  /* Dashboard nav — only icons on tiny screens */
  .dash-nav { padding: 0 12px; height: 56px; }
  .dash-nav-brand { font-size: 17px; letter-spacing: .04em; }
  .dash-nav-right { gap: 8px; }
  .dash-user-info { display: none; }
  .btn-signout { padding: 7px 8px; border-radius: 8px; }
  .btn-signout-label { display: none; }
  .btn-admin { padding: 7px 8px; font-size: 11px; gap: 4px; }
  .btn-admin span.admin-label { display: none; }
}

#course-screen { overflow-x: hidden; }


.pill-logo { width: 20px; height: 20px; flex-shrink: 0; border-radius: 4px; }
.tool-pill { gap: 9px; }

/* =========================================================
   Refinamiento editorial 2026 — curso
   ========================================================= */
#course-screen { background: #fff; }
.sidebar { width: 288px; background: var(--paper); border-right: 1px solid var(--border); }
.sidebar-logo { padding: 22px 22px 20px; border-bottom: 1px solid var(--border); }
.sidebar-back {
  display: inline-flex; align-items: center; gap: 6px; margin-bottom: 18px;
  background: none; border: 0; cursor: pointer; color: var(--text3); font-size: 13px; font-weight: 500;
}
.sidebar-back:hover { color: var(--ink); }
.sidebar-back svg { width: 15px; height: 15px; fill: none; stroke: currentColor; stroke-width: 2; stroke-linecap: round; stroke-linejoin: round; }
.sidebar-logo .logo-badge { background: var(--accent-soft); border: 0; color: var(--accent); border-radius: 999px; padding: 4px 10px; font-size: 11px; letter-spacing: .04em; margin-bottom: 12px; }
.sidebar-logo h1 { font: 700 19px/1.2 var(--font); letter-spacing: -.02em; color: var(--ink); }
.sidebar-logo p { font-size: 13px; color: var(--text3); margin-top: 6px; }
.progress-wrap { padding: 18px 22px; }
.progress-label { font-family: var(--font); font-size: 12px; font-weight: 500; color: var(--text2); }
.progress-label #prog-text { font-family: var(--font-mono); color: var(--accent); }
.progress-bar { height: 6px; border-radius: 6px; background: var(--bg4); }
.progress-fill, .progress-fill { background: var(--accent); animation: none; border-radius: 6px; }
.nav-section { padding: 18px 12px 4px; }
.nav-section-title { font: 600 11px/1.3 var(--font); letter-spacing: .06em; color: var(--text3); padding: 0 10px; margin-bottom: 6px; }
.nav-item { padding: 9px 10px; border-radius: 10px; font-size: 14px; line-height: 1.35; color: var(--text2); border: 1px solid transparent; }
.nav-item:hover { background: #fff; color: var(--ink); }
.nav-item.active { background: #fff; color: var(--accent); border: 1px solid var(--border); box-shadow: var(--shadow-sm); font-weight: 600; }
.nav-item.active::before { left: -1px; top: 9px; bottom: 9px; }
.nav-item .nav-check { width: 18px; height: 18px; border: 1.5px solid var(--border2); font-size: 0; color: transparent; }
.nav-item.done .nav-check { background: var(--green); border-color: var(--green); }
.nav-item.done .nav-check::after { content: ""; width: 8px; height: 4px; border: solid #fff; border-width: 0 0 2px 2px; transform: translateY(-1px) rotate(-45deg); }
.nav-icon svg { width: 16px; height: 16px; }
.sidebar-footer { font-size: 12px; color: var(--text3); padding: 18px 22px 22px; line-height: 1.5; }
.reset-btn { font-family: var(--font); font-size: 12px; letter-spacing: 0; border-color: var(--border2); border-radius: 10px; padding: 9px 12px; }

.main { margin-left: 288px; background: #fff; }
.topbar { padding: 12px clamp(16px, 4vw, 48px); background: rgba(255,255,255,.88); backdrop-filter: saturate(1.4) blur(14px); -webkit-backdrop-filter: saturate(1.4) blur(14px); border-bottom: 1px solid var(--border); box-shadow: none; min-height: 64px; }
.topbar-breadcrumb { font-family: var(--font); font-size: 13px; color: var(--text3); }
.topbar-breadcrumb span { color: var(--ink); font-weight: 600; }
.topbar-actions { gap: 8px; }
.btn { border-radius: 999px; font-family: var(--font); font-weight: 600; font-size: 14px; padding: 9px 18px; display: inline-flex; align-items: center; gap: 6px; }
.btn:hover { transform: none; }
.btn:active { transform: scale(.98); }
.btn-ghost { background: #fff; border: 1px solid var(--border2); color: var(--ink); }
.btn-ghost:hover { background: var(--bg2); border-color: var(--ink); color: var(--ink); }
.btn-primary { background: var(--accent); color: #fff; }
.btn-primary:hover { background: var(--accent-hover); box-shadow: 0 8px 20px -8px rgba(26,86,232,.6); }

.lesson { padding: 56px clamp(16px, 5vw, 72px) 96px; max-width: 920px; }
.hero-lesson { padding: 72px clamp(16px, 5vw, 72px) 24px !important; max-width: 920px; }
.lesson-header { margin-bottom: 40px; padding-bottom: 32px; }
.lesson-tag { font-family: var(--font-mono); font-size: 11px; letter-spacing: .04em; border: 0; background: var(--accent-soft); border-radius: 999px; padding: 5px 12px; }
.lesson h1, .hero-lesson h1 {
  font-family: var(--font); font-weight: 700; letter-spacing: -.035em; color: var(--ink);
  background: none; -webkit-text-fill-color: currentColor; animation: none;
}
.lesson h1 { font-size: clamp(32px, 4.4vw, 48px); line-height: 1.04; margin-bottom: 14px; }
.hero-lesson h1 { font-size: clamp(38px, 6vw, 68px); line-height: .98; margin-bottom: 22px; }
.hero-eyebrow { font-family: var(--font-mono); font-size: 12px; letter-spacing: .06em; color: var(--accent); }
.hero-eyebrow::after { content: none; }
.lesson-intro, .hero-lesson .subtitle { font-size: 18px; color: var(--text2); line-height: 1.7; }
h2.section-title { font: 700 clamp(22px, 2.6vw, 28px)/1.2 var(--font); letter-spacing: -.025em; margin: 56px 0 18px; color: var(--ink); }
h2.section-title::before { width: 3px; height: 1.05em; border-radius: 3px; background: var(--accent); animation: none; }
h3.sub-title { font: 650 20px/1.3 var(--font); letter-spacing: -.02em; }
p.body-text { font-size: 16.5px; line-height: 1.8; color: var(--text2); }
.card, .tool-card, .quiz-card, .diagram-wrap, .mod-card { background: #fff; border: 1px solid var(--border); border-radius: var(--radius); box-shadow: var(--shadow-sm); }
.card:hover { transform: translateY(-2px); box-shadow: var(--shadow); border-color: var(--border2); }
.card h4, .mod-card h3, .tool-name, .compare-cell h5, .quiz-card h4 { font-family: var(--font); font-weight: 650; letter-spacing: -.015em; }
.mod-card { padding: 22px; }
.mod-card:hover { transform: translateY(-3px); box-shadow: var(--shadow); border-color: var(--border2); background: #fff; }
.mod-num { font-family: var(--font-mono); color: var(--accent); }
.mod-card h3 { font-size: 18px; margin-bottom: 6px; }
.mod-card p { font-size: 14px; color: var(--text3); line-height: 1.55; }
.tool-pill { background: #fff; border: 1px solid var(--border); border-radius: 12px; font-size: 13px; color: var(--ink); padding: 11px 14px; }
.tool-pill:hover { transform: translateY(-2px); background: #fff; box-shadow: var(--shadow); border-color: var(--border2); color: var(--ink); }
.callout { border-radius: 12px; border-left-width: 3px; font-size: 15px; animation: none; }
.code-wrap { border-radius: 12px; border: 1px solid #1c2a52; }
.code-header { background: #070f26; }
pre { background: #0b1634; font-size: 13.5px; }
.step-num { background: var(--ink); border: 0; color: #fff; font-family: var(--font-mono); }
.step:hover .step-num { animation: none; color: #fff; }
.checklist li::before { content: ""; width: 16px; height: 16px; margin-top: 3px; border-radius: 50%; background: var(--accent-soft) url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%231a56e8' stroke-width='3.2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpolyline points='20 6 9 17 4 12'/%3E%3C/svg%3E") center/10px no-repeat; }
.checklist li:hover { padding-left: 0; }
.quiz-opt { background: #fff; border-color: var(--border2); border-radius: 12px; }
.quiz-opt:hover { transform: none; background: var(--accent-soft); border-color: var(--accent); color: var(--ink); }
.lesson-nav { margin-top: 72px; }
.anim-enter { transform: translateY(14px); transition: opacity .5s var(--ease), transform .5s var(--ease); }

@media (max-width: 900px) {
  .sidebar { box-shadow: none; }
  .main { margin-left: 0; }
}
@media (max-width: 768px) {
  .sidebar { left: -300px; width: 288px; }
  .sidebar.open { left: 0; box-shadow: 0 0 0 100vmax rgba(10,20,48,.0), 12px 0 40px rgba(10,20,48,.25); }
  .topbar { min-height: 58px; }
  .lesson, .hero-lesson { padding-left: 18px !important; padding-right: 18px !important; }
}
@media (max-width: 768px) { .topbar-back { display: none !important; } }
.btn-label-short { display: none; }
@media (max-width: 480px) {
  .topbar-actions .btn-label-full { display: none; }
  .topbar-actions .btn-label-short { display: inline; }
}