/* ==========================================================================
   ElectroCalc — Design System
   Paleta técnica: azul de instrumentação sobre branco/laboratório.
   Tipografia: Inter (interface) + JetBrains Mono (valores/dados/unidades).
   ========================================================================== */

@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700;800&family=JetBrains+Mono:wght@400;500;600;700&display=swap');

:root {
  --background: #FFFFFF;
  --background-secondary: #F5F9FF;
  --primary: #2563EB;
  --primary-hover: #1D4ED8;
  --accent: #60A5FA;
  --text: #1E293B;
  --text-secondary: #64748B;
  --border: #E2E8F0;
  --card: #FFFFFF;
  --success: #22C55E;
  --warning: #F59E0B;
  --danger: #EF4444;

  --font-ui: 'Inter', system-ui, -apple-system, sans-serif;
  --font-mono: 'JetBrains Mono', 'SFMono-Regular', Menlo, monospace;

  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --shadow-sm: 0 1px 2px rgba(30, 41, 59, 0.06);
  --shadow-md: 0 4px 16px rgba(37, 99, 235, 0.08);
  --shadow-lg: 0 12px 32px rgba(37, 99, 235, 0.12);
  --max-width: 1120px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: var(--font-ui);
  background: var(--background);
  color: var(--text);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

img { max-width: 100%; display: block; }
a { color: var(--primary); text-decoration: none; }
a:hover { color: var(--primary-hover); }

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

/* ---------- Circuito decorativo (marca visual) ---------- */
.circuit-rule {
  height: 3px;
  width: 100%;
  background:
    linear-gradient(90deg, var(--primary) 0 8px, transparent 8px 16px) repeat-x;
  background-size: 16px 3px;
  opacity: .55;
}

/* ---------- Header / navegação ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(255,255,255,0.9);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--border);
}

.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 0;
  gap: 16px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 800;
  font-size: 1.15rem;
  color: var(--text);
  letter-spacing: -0.02em;
}
.brand:hover { color: var(--text); }

.brand-mark {
  width: 34px;
  height: 34px;
  border-radius: 8px;
  background: linear-gradient(135deg, var(--primary), var(--accent));
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}
.brand-mark svg { width: 20px; height: 20px; }
.brand small {
  display: block;
  font-family: var(--font-mono);
  font-weight: 500;
  font-size: 0.62rem;
  color: var(--text-secondary);
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.nav-toggle {
  display: none;
  background: none;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  width: 40px;
  height: 40px;
  align-items: center;
  justify-content: center;
  cursor: pointer;
}
.nav-toggle svg { width: 20px; height: 20px; stroke: var(--text); }

.nav-links {
  display: flex;
  flex-wrap: wrap;
  gap: 4px;
  justify-content: flex-end;
}

.nav-links a {
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--text-secondary);
  padding: 8px 10px;
  border-radius: var(--radius-sm);
  white-space: nowrap;
}
.nav-links a:hover { background: var(--background-secondary); color: var(--primary); }
.nav-links a.active { color: var(--primary); background: var(--background-secondary); }

/* ---------- Hero ---------- */
.hero {
  background: var(--background-secondary);
  border-bottom: 1px solid var(--border);
  padding: 56px 0 64px;
  position: relative;
  overflow: hidden;
}

.hero-eyebrow {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--primary);
  display: inline-flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 14px;
}
.hero-eyebrow::before {
  content: '';
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--success);
  box-shadow: 0 0 0 3px rgba(34,197,94,0.18);
}

.hero h1 {
  font-size: clamp(1.9rem, 4vw, 2.9rem);
  font-weight: 800;
  letter-spacing: -0.03em;
  margin: 0 0 14px;
  max-width: 780px;
}
.hero p.lead {
  font-size: 1.05rem;
  color: var(--text-secondary);
  max-width: 620px;
  margin: 0 0 26px;
}

.breadcrumb {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--text-secondary);
  margin-bottom: 16px;
}
.breadcrumb a { color: var(--text-secondary); }
.breadcrumb a:hover { color: var(--primary); }
.breadcrumb .sep { margin: 0 6px; opacity: .5; }

/* ---------- Botões ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 20px;
  border-radius: var(--radius-sm);
  font-weight: 600;
  font-size: 0.9rem;
  border: 1px solid transparent;
  cursor: pointer;
  transition: transform .12s ease, box-shadow .12s ease, background .12s ease;
}
.btn-primary { background: var(--primary); color: #fff; box-shadow: var(--shadow-sm); }
.btn-primary:hover { background: var(--primary-hover); color: #fff; box-shadow: var(--shadow-md); }
.btn-ghost { background: var(--background); border-color: var(--border); color: var(--text); }
.btn-ghost:hover { border-color: var(--primary); color: var(--primary); }
.btn:active { transform: translateY(1px); }

/* ---------- Grid de calculadoras (home) ---------- */
.section { padding: 56px 0; }
.section-head { margin-bottom: 30px; max-width: 640px; }
.section-head .kicker {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--primary);
}
.section-head h2 {
  font-size: clamp(1.4rem, 2.6vw, 1.9rem);
  letter-spacing: -0.02em;
  margin: 8px 0 10px;
}
.section-head p { color: var(--text-secondary); margin: 0; }

.grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
  gap: 16px;
}

.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 22px;
  transition: transform .15s ease, box-shadow .15s ease, border-color .15s ease;
  display: flex;
  flex-direction: column;
  gap: 10px;
  height: 100%;
}
.card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-md);
  border-color: var(--accent);
}

.card-icon {
  width: 42px;
  height: 42px;
  border-radius: var(--radius-sm);
  background: var(--background-secondary);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--primary);
}
.card-icon svg { width: 22px; height: 22px; }

.card h3 { margin: 0; font-size: 1.02rem; letter-spacing: -0.01em; }
.card p { margin: 0; font-size: 0.86rem; color: var(--text-secondary); flex-grow: 1; }
.card .card-tag {
  font-family: var(--font-mono);
  font-size: 0.68rem;
  color: var(--primary);
  text-transform: uppercase;
  letter-spacing: 0.06em;
}
.card .card-link {
  font-size: 0.83rem;
  font-weight: 600;
  color: var(--primary);
  display: inline-flex;
  align-items: center;
  gap: 4px;
}
.card .card-link svg { width: 14px; height: 14px; transition: transform .15s ease; }
.card:hover .card-link svg { transform: translateX(3px); }

/* ---------- Calculadora ---------- */
.calc-wrap {
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: 24px;
  align-items: start;
}
@media (max-width: 860px) { .calc-wrap { grid-template-columns: 1fr; } }

.calc-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 28px;
  box-shadow: var(--shadow-sm);
}
.calc-card h2 {
  font-size: 1.1rem;
  margin: 0 0 4px;
  letter-spacing: -0.01em;
}
.calc-card .calc-sub { color: var(--text-secondary); font-size: 0.86rem; margin: 0 0 22px; }

.field { margin-bottom: 16px; }
.field label {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  font-size: 0.82rem;
  font-weight: 600;
  margin-bottom: 6px;
  color: var(--text);
}
.field label .unit {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--text-secondary);
  font-weight: 500;
}
.field input,
.field select {
  width: 100%;
  padding: 11px 12px;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  font-family: var(--font-mono);
  font-size: 0.95rem;
  color: var(--text);
  background: var(--background);
  transition: border-color .12s ease, box-shadow .12s ease;
}
.field input:focus,
.field select:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(37,99,235,0.12);
}
.field .hint { font-size: 0.76rem; color: var(--text-secondary); margin-top: 5px; }

.field-row { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; }
@media (max-width: 480px) { .field-row { grid-template-columns: 1fr; } }

.radio-group { display: flex; gap: 8px; flex-wrap: wrap; }
.radio-group label {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 0.82rem;
  font-weight: 500;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 8px 12px;
  cursor: pointer;
  color: var(--text-secondary);
}
.radio-group input { accent-color: var(--primary); width: auto; margin: 0; }
.radio-group label:has(input:checked) { border-color: var(--primary); color: var(--primary); background: var(--background-secondary); }

.calc-actions { display: flex; gap: 10px; margin-top: 8px; }

.result-card {
  background: var(--background-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 26px;
  position: sticky;
  top: 90px;
}
.result-card h3 {
  font-size: 0.78rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-secondary);
  margin: 0 0 18px;
}
.result-main {
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 2rem;
  color: var(--primary);
  line-height: 1.15;
  word-break: break-word;
}
.result-main .u { font-size: 1rem; color: var(--text-secondary); font-weight: 600; margin-left: 4px; }
.result-list { margin-top: 18px; display: flex; flex-direction: column; gap: 10px; }
.result-row {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  font-size: 0.86rem;
  padding-bottom: 10px;
  border-bottom: 1px dashed var(--border);
}
.result-row:last-child { border-bottom: none; padding-bottom: 0; }
.result-row .k { color: var(--text-secondary); }
.result-row .v { font-family: var(--font-mono); font-weight: 600; }

.badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 5px 11px;
  border-radius: 100px;
  font-size: 0.74rem;
  font-weight: 700;
  font-family: var(--font-mono);
}
.badge-ok { background: rgba(34,197,94,0.12); color: #16803d; }
.badge-warn { background: rgba(245,158,11,0.14); color: #b45309; }
.badge-danger { background: rgba(239,68,68,0.12); color: #b91c1c; }

.note {
  border-left: 3px solid var(--accent);
  background: var(--background-secondary);
  padding: 14px 16px;
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  font-size: 0.87rem;
  color: var(--text-secondary);
  margin: 20px 0;
}
.note strong { color: var(--text); }
.note.warning { border-left-color: var(--warning); }
.note.danger { border-left-color: var(--danger); }

/* ---------- Conteúdo / artigo ---------- */
.prose { max-width: 760px; }
.prose h2 {
  font-size: 1.35rem;
  letter-spacing: -0.02em;
  margin: 40px 0 14px;
  padding-top: 4px;
}
.prose h2:first-child { margin-top: 0; }
.prose h3 { font-size: 1.05rem; margin: 26px 0 10px; }
.prose p { color: var(--text); margin: 0 0 14px; }
.prose ul, .prose ol { color: var(--text); padding-left: 22px; margin: 0 0 16px; }
.prose li { margin-bottom: 6px; }
.prose code {
  font-family: var(--font-mono);
  background: var(--background-secondary);
  padding: 2px 6px;
  border-radius: 4px;
  font-size: 0.88em;
  color: var(--primary-hover);
}
.formula {
  font-family: var(--font-mono);
  background: var(--text);
  color: #E0EAFF;
  padding: 18px 22px;
  border-radius: var(--radius-md);
  font-size: 1.02rem;
  margin: 18px 0;
  overflow-x: auto;
}
.formula .comment { color: #93C5FD; opacity: .8; }

/* ---------- Tabelas ---------- */
.table-wrap { overflow-x: auto; border: 1px solid var(--border); border-radius: var(--radius-md); margin: 18px 0; }
table { width: 100%; border-collapse: collapse; font-size: 0.86rem; min-width: 480px; }
thead th {
  background: var(--background-secondary);
  text-align: left;
  padding: 12px 14px;
  font-weight: 700;
  font-size: 0.76rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--text-secondary);
  border-bottom: 1px solid var(--border);
  white-space: nowrap;
}
tbody td {
  padding: 11px 14px;
  border-bottom: 1px solid var(--border);
  font-family: var(--font-mono);
  color: var(--text);
  white-space: nowrap;
}
tbody tr:last-child td { border-bottom: none; }
tbody tr:hover { background: var(--background-secondary); }

/* ---------- Related / cross-links ---------- */
.related { background: var(--background-secondary); border-top: 1px solid var(--border); border-bottom: 1px solid var(--border); }
.related .grid { grid-template-columns: repeat(auto-fill, minmax(220px, 1fr)); }

/* ---------- Footer ---------- */
.site-footer { background: var(--text); color: #CBD5E1; padding: 48px 0 28px; margin-top: 40px; }
.footer-grid {
  display: grid;
  grid-template-columns: 1.4fr 1fr 1fr 1fr;
  gap: 32px;
  margin-bottom: 30px;
}
@media (max-width: 760px) { .footer-grid { grid-template-columns: 1fr 1fr; } }
.footer-grid h4 { color: #fff; font-size: 0.8rem; text-transform: uppercase; letter-spacing: 0.06em; margin: 0 0 14px; }
.footer-grid ul { list-style: none; padding: 0; margin: 0; display: flex; flex-direction: column; gap: 9px; }
.footer-grid a { color: #94A3B8; font-size: 0.86rem; }
.footer-grid a:hover { color: #fff; }
.footer-brand p { color: #94A3B8; font-size: 0.86rem; max-width: 280px; }
.footer-bottom {
  border-top: 1px solid #334155;
  padding-top: 22px;
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 10px;
  font-size: 0.78rem;
  color: #64748B;
  font-family: var(--font-mono);
}

/* ---------- Ad slots ---------- */
.ad-slot {
  background: var(--background-secondary);
  border: 1px dashed var(--border);
  border-radius: var(--radius-md);
  padding: 18px;
  text-align: center;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--text-secondary);
  letter-spacing: 0.05em;
  text-transform: uppercase;
  margin: 32px 0;
}

/* ---------- Utilities ---------- */
.mt-0 { margin-top: 0; }
.text-center { text-align: center; }
.sr-only { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0,0,0,0); }

@media (max-width: 760px) {
  .nav-toggle { display: flex; }
  .nav-links {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: var(--background);
    border-bottom: 1px solid var(--border);
    flex-direction: column;
    padding: 10px 16px 18px;
    box-shadow: var(--shadow-md);
  }
  .nav-links.open { display: flex; }
  .nav-links a { padding: 12px 10px; }
  .result-card { position: static; }
}