/* ===================================================
   CÁLCULO DIFERENCIAL — Content Page Styles
   =================================================== */

/* --- Page Layout --- */
.page-wrapper {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* Top progress line */
.page-wrapper::before {
  content: '';
  position: fixed;
  top: 0; left: 0; right: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--brand-from), var(--brand-to));
  z-index: 100;
}

/* --- Top Nav Bar --- */
.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-md) var(--space-xl);
  background: rgba(13, 15, 26, 0.8);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border-subtle);
  position: sticky;
  top: 0;
  z-index: 50;
}

.topbar-brand {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  font-weight: 700;
  font-size: 0.9rem;
  color: var(--text-primary);
  text-decoration: none;
}

.topbar-brand .brand-icon {
  width: 32px; height: 32px;
  background: linear-gradient(135deg, var(--brand-from), var(--brand-to));
  border-radius: var(--radius-sm);
  display: flex; align-items: center; justify-content: center;
  font-size: 0.9rem;
}

.topbar-meta {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  font-size: 0.8rem;
  color: var(--text-muted);
}

.topbar-nav {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

/* --- Hero Section --- */
.hero {
  padding: var(--space-3xl) var(--space-xl) var(--space-2xl);
  max-width: var(--content-max-width);
  margin: 0 auto;
  width: 100%;
}

.hero-eyebrow {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  margin-bottom: var(--space-lg);
}

.hero-title {
  margin-bottom: var(--space-md);
}

.hero-subtitle {
  font-size: 1.05rem;
  color: var(--text-secondary);
  max-width: 580px;
  margin-bottom: var(--space-xl);
}

.hero-meta {
  display: flex;
  align-items: center;
  gap: var(--space-lg);
  flex-wrap: wrap;
}

.hero-meta-item {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  font-size: 0.82rem;
  color: var(--text-muted);
}

.hero-meta-item svg, .hero-meta-item .icon {
  width: 14px; height: 14px;
  opacity: 0.7;
}

/* --- Main Content --- */
.content-main {
  flex: 1;
  max-width: var(--content-max-width);
  margin: 0 auto;
  padding: 0 var(--space-xl) var(--space-3xl);
  width: 100%;
}

/* --- Section --- */
.section {
  margin-bottom: var(--space-3xl);
}

.section-header {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  margin-bottom: var(--space-xl);
  padding-bottom: var(--space-md);
  border-bottom: 1px solid var(--border-subtle);
}

.section-number {
  width: 36px; height: 36px;
  background: linear-gradient(135deg, var(--brand-from), var(--brand-to));
  border-radius: var(--radius-sm);
  display: flex; align-items: center; justify-content: center;
  font-size: 0.85rem;
  font-weight: 700;
  color: white;
  flex-shrink: 0;
}

/* --- Concept Box — Definition, Theorem, Note --- */
.concept-box {
  border-radius: var(--radius-lg);
  padding: var(--space-xl);
  margin: var(--space-xl) 0;
  position: relative;
  overflow: hidden;
}

.concept-box::before {
  content: '';
  position: absolute;
  top: 0; left: 0;
  width: 4px; height: 100%;
}

.concept-box-definition {
  background: rgba(108, 99, 255, 0.08);
  border: 1px solid rgba(108, 99, 255, 0.2);
}
.concept-box-definition::before { background: var(--brand-from); }

.concept-box-theorem {
  background: rgba(34, 211, 238, 0.06);
  border: 1px solid rgba(34, 211, 238, 0.2);
}
.concept-box-theorem::before { background: var(--accent-teal); }

.concept-box-example {
  background: rgba(251, 191, 36, 0.06);
  border: 1px solid rgba(251, 191, 36, 0.15);
}
.concept-box-example::before { background: var(--accent-amber); }

.concept-box-note {
  background: rgba(74, 222, 128, 0.06);
  border: 1px solid rgba(74, 222, 128, 0.15);
}
.concept-box-note::before { background: var(--accent-green); }

.concept-box-warning {
  background: rgba(244, 63, 94, 0.06);
  border: 1px solid rgba(244, 63, 94, 0.2);
}
.concept-box-warning::before { background: var(--accent-rose); }

.concept-box-label {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  margin-bottom: var(--space-md);
  opacity: 0.9;
}

.concept-box-definition .concept-box-label { color: var(--brand-to); }
.concept-box-theorem   .concept-box-label  { color: var(--accent-teal); }
.concept-box-example   .concept-box-label  { color: var(--accent-amber); }
.concept-box-note      .concept-box-label  { color: var(--accent-green); }
.concept-box-warning   .concept-box-label  { color: var(--accent-rose); }

.concept-box-title {
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: var(--space-sm);
}

.concept-box p { color: var(--text-secondary); margin-bottom: var(--space-sm); }
.concept-box p:last-child { margin-bottom: 0; }

/* --- Math Display Block --- */
.math-block {
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: var(--space-lg) var(--space-xl);
  margin: var(--space-lg) 0;
  overflow-x: auto;
  text-align: center;
}

.math-block.highlighted {
  background: rgba(108, 99, 255, 0.06);
  border-color: rgba(108, 99, 255, 0.25);
  box-shadow: inset 0 0 30px rgba(108, 99, 255, 0.05);
}

/* --- Interactive Graph Container --- */
.graph-container {
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  overflow: hidden;
  margin: var(--space-xl) 0;
}

.graph-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-md) var(--space-lg);
  border-bottom: 1px solid var(--border-subtle);
}

.graph-title {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-secondary);
  display: flex;
  align-items: center;
  gap: 0.4rem;
}

.graph-frame {
  width: 100%;
  height: 380px;
  border: none;
  display: block;
}

.graph-caption {
  padding: var(--space-md) var(--space-lg);
  font-size: 0.8rem;
  color: var(--text-muted);
  border-top: 1px solid var(--border-subtle);
  text-align: center;
}

/* --- Step-by-step --- */
.steps-list {
  list-style: none;
  counter-reset: step-counter;
}

.step-item {
  display: flex;
  gap: var(--space-lg);
  padding: var(--space-lg) 0;
  border-bottom: 1px solid var(--border-subtle);
  animation: fadeInUp 0.4s var(--ease-out) both;
}

.step-item:last-child { border-bottom: none; }

.step-counter {
  counter-increment: step-counter;
  width: 32px; height: 32px;
  background: var(--bg-elevated);
  border: 1px solid var(--border-normal);
  border-radius: var(--radius-sm);
  display: flex; align-items: center; justify-content: center;
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--brand-to);
  flex-shrink: 0;
  margin-top: 2px;
  transition: all var(--duration-normal) var(--ease-out);
}

.step-item:hover .step-counter {
  background: var(--brand-glow);
  border-color: var(--brand-from);
}

.step-content p { margin-bottom: var(--space-sm); }

/* --- Info Grid --- */
.info-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: var(--space-md);
  margin: var(--space-xl) 0;
}

.info-card {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: var(--space-lg);
  text-align: center;
  transition: all var(--duration-normal) var(--ease-out);
}

.info-card:hover {
  border-color: var(--border-strong);
  transform: translateY(-2px);
  box-shadow: var(--shadow-brand);
}

.info-card-icon {
  font-size: 2rem;
  margin-bottom: var(--space-sm);
  display: block;
}

.info-card-value {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: var(--space-xs);
}

.info-card-label {
  font-size: 0.8rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

/* --- Navigation Footer --- */
.nav-footer {
  border-top: 1px solid var(--border-subtle);
  padding: var(--space-xl);
  max-width: var(--content-max-width);
  margin: 0 auto;
  width: 100%;
}

.nav-footer-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-md);
}

.nav-footer-info {
  font-size: 0.8rem;
  color: var(--text-muted);
  text-align: center;
}

/* --- Callout highlight --- */
.highlight-box {
  background: linear-gradient(135deg, rgba(108,99,255,0.1), rgba(167,139,250,0.05));
  border: 1px solid rgba(108,99,255,0.25);
  border-radius: var(--radius-lg);
  padding: var(--space-xl);
  margin: var(--space-xl) 0;
  position: relative;
}

.highlight-box::after {
  content: '';
  position: absolute;
  top: -1px; left: 24px;
  right: 24px; height: 2px;
  background: linear-gradient(90deg, var(--brand-from), var(--brand-to));
  border-radius: 0 0 var(--radius-sm) var(--radius-sm);
}

/* --- Table --- */
.math-table {
  width: 100%;
  border-collapse: collapse;
  margin: var(--space-xl) 0;
  font-size: 0.9rem;
}

.math-table th {
  background: var(--bg-elevated);
  color: var(--brand-to);
  font-weight: 600;
  font-size: 0.75rem;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  padding: 0.75rem 1rem;
  text-align: left;
  border-bottom: 2px solid var(--border-normal);
}

.math-table td {
  padding: 0.75rem 1rem;
  border-bottom: 1px solid var(--border-subtle);
  color: var(--text-secondary);
}

.math-table tr:last-child td { border-bottom: none; }
.math-table tr:hover td {
  background: var(--bg-surface);
  color: var(--text-primary);
}

/* --- Responsive --- */
@media (max-width: 640px) {
  .hero        { padding: var(--space-xl) var(--space-md) var(--space-lg); }
  .content-main{ padding: 0 var(--space-md) var(--space-2xl); }
  .topbar      { padding: var(--space-sm) var(--space-md); }
  .graph-frame { height: 280px; }
  .nav-footer  { padding: var(--space-lg) var(--space-md); }
  .hero-meta   { gap: var(--space-md); }

  .nav-footer-inner {
    flex-direction: column;
    text-align: center;
  }
}