/* ============================================================
   PhysicsLab3D — Design System
   Direção visual: minimalismo Apple — SF Pro / Inter
   Fundo branco, tipografia precisa, sombras sutis
   ============================================================ */

@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&display=swap');

/* ── TOKENS ─────────────────────────────────────────────────── */
:root {
  /* Superfícies */
  --surface-base:    #ffffff;
  --surface-raised:  #ffffff;
  --surface-subtle:  #f5f5f7;
  --surface-inset:   #f0f0f2;

  /* Bordas */
  --border-soft:     rgba(0, 0, 0, 0.08);
  --border-medium:   rgba(0, 0, 0, 0.12);

  /* Texto */
  --text-primary:    #1d1d1f;
  --text-secondary:  #6e6e73;
  --text-tertiary:   #aeaeb2;
  --text-on-accent:  #ffffff;

  /* Ação */
  --accent:          #0071e3;
  --accent-hover:    #0077ed;
  --accent-subtle:   rgba(0, 113, 227, 0.08);
  --accent-subtle-h: rgba(0, 113, 227, 0.13);

  /* Semântica — apenas para os pontos das cargas */
  --charge-pos:      #ff3b30;
  --charge-neg:      #0071e3;

  /* Sombras */
  --shadow-xs:  0 1px 3px rgba(0, 0, 0, 0.06), 0 1px 2px rgba(0, 0, 0, 0.04);
  --shadow-sm:  0 2px 8px rgba(0, 0, 0, 0.07), 0 1px 3px rgba(0, 0, 0, 0.05);
  --shadow-md:  0 4px 16px rgba(0, 0, 0, 0.08), 0 2px 6px rgba(0, 0, 0, 0.05);

  /* Tipografia */
  --font-ui:   'Inter', -apple-system, BlinkMacSystemFont, 'Helvetica Neue', sans-serif;
  --font-mono: 'SF Mono', 'Fira Code', 'Menlo', monospace;

  /* Forma */
  --radius-sm:  8px;
  --radius-md:  12px;
  --radius-lg:  16px;
  --radius-xl:  20px;

  /* Ritmo */
  --transition: 0.18s cubic-bezier(0.4, 0, 0.2, 1);
}

/* ── RESET ──────────────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; -webkit-font-smoothing: antialiased; }

body {
  font-family: var(--font-ui);
  background: var(--surface-base);
  color: var(--text-primary);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  overflow-x: hidden;
}

/* ── SCROLLBAR ──────────────────────────────────────────────── */
::-webkit-scrollbar { width: 5px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--border-medium); border-radius: 10px; }

/* ============================================================
   HEADER
   ============================================================ */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255, 255, 255, 0.88);
  backdrop-filter: saturate(180%) blur(20px);
  -webkit-backdrop-filter: saturate(180%) blur(20px);
  border-bottom: 1px solid var(--border-soft);
}

.header-inner {
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 32px;
  height: 60px;
  display: flex;
  align-items: center;
  gap: 40px;
}

/* Logo */
.logo {
  display: flex;
  align-items: center;
  gap: 0;
  text-decoration: none;
  flex-shrink: 0;
}
.logo-icon { display: none; }
.logo-text {
  font-size: 17px;
  font-weight: 600;
  color: var(--text-primary);
  letter-spacing: -0.3px;
}
.logo-accent {
  color: var(--accent);
  font-weight: 600;
}

/* Navigation */
.main-nav {
  display: flex;
  gap: 2px;
  flex: 1;
  overflow-x: auto;
  scrollbar-width: none;
}
.main-nav::-webkit-scrollbar { display: none; }

.nav-btn {
  background: transparent;
  border: none;
  color: var(--text-secondary);
  padding: 6px 14px;
  border-radius: 980px;
  font-family: var(--font-ui);
  font-size: 13.5px;
  font-weight: 400;
  cursor: pointer;
  white-space: nowrap;
  transition: all var(--transition);
  letter-spacing: -0.1px;
}
.nav-btn:hover {
  color: var(--text-primary);
  background: var(--surface-subtle);
}
.nav-btn.active {
  background: var(--accent-subtle);
  color: var(--accent);
  font-weight: 500;
}

/* Classroom button */
.classroom-btn {
  background: var(--surface-subtle);
  border: 1px solid var(--border-soft);
  color: var(--text-secondary);
  padding: 6px 16px;
  border-radius: 980px;
  font-family: var(--font-ui);
  font-size: 13px;
  font-weight: 500;
  cursor: pointer;
  white-space: nowrap;
  transition: all var(--transition);
  flex-shrink: 0;
}
.classroom-btn:hover {
  background: var(--surface-inset);
  color: var(--text-primary);
  border-color: var(--border-medium);
}
.classroom-btn.active {
  background: var(--accent);
  color: var(--text-on-accent);
  border-color: transparent;
}

/* ── CLASSROOM BANNER ───────────────────────────────────────── */
.classroom-banner {
  background: var(--surface-subtle);
  border-bottom: 1px solid var(--border-soft);
  padding: 10px 32px;
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 13.5px;
  color: var(--text-secondary);
}
.classroom-banner.hidden { display: none; }
.classroom-icon { display: none; }
.classroom-banner strong { color: var(--text-primary); font-weight: 500; }
.close-banner {
  margin-left: auto;
  background: transparent;
  border: none;
  color: var(--text-tertiary);
  font-size: 18px;
  cursor: pointer;
  line-height: 1;
  padding: 2px 6px;
  border-radius: 50%;
  transition: all var(--transition);
}
.close-banner:hover {
  background: var(--surface-inset);
  color: var(--text-secondary);
}

/* ============================================================
   MAIN CONTENT
   ============================================================ */
.main-content {
  flex: 1;
  max-width: 1280px;
  margin: 0 auto;
  width: 100%;
  padding: 48px 32px 64px;
}

/* ── MODULES ────────────────────────────────────────────────── */
.module { display: none; animation: moduleFadeIn 0.28s ease; }
.module.active { display: block; }

@keyframes moduleFadeIn {
  from { opacity: 0; transform: translateY(10px); }
  to   { opacity: 1; transform: translateY(0); }
}

/* Module header */
.module-header { margin-bottom: 36px; }

.module-title {
  font-size: 34px;
  font-weight: 700;
  color: var(--text-primary);
  letter-spacing: -0.8px;
  line-height: 1.1;
}
.module-subtitle {
  font-family: var(--font-mono);
  font-size: 15px;
  color: var(--text-tertiary);
  margin-top: 6px;
  letter-spacing: 0.2px;
  font-weight: 400;
}

/* Module layout */
.module-layout {
  display: grid;
  grid-template-columns: 1fr 360px;
  gap: 24px;
  align-items: start;
}
@media (max-width: 960px) {
  .module-layout { grid-template-columns: 1fr; }
}

/* ── CANVAS PANEL ───────────────────────────────────────────── */
.canvas-panel {
  background: var(--surface-subtle);
  border: 1px solid var(--border-soft);
  border-radius: var(--radius-xl);
  overflow: hidden;
  position: relative;
  aspect-ratio: 16 / 9;
  box-shadow: var(--shadow-sm);
}
.canvas-panel.large-canvas { aspect-ratio: 4 / 3; }

.canvas-panel canvas {
  width: 100% !important;
  height: 100% !important;
  display: block;
}

/* No more scan-line pseudo-element */
.canvas-panel::after { display: none; }

.canvas-label {
  position: absolute;
  bottom: 14px;
  left: 14px;
  font-size: 11px;
  font-weight: 500;
  color: var(--text-tertiary);
  background: rgba(255, 255, 255, 0.80);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  padding: 4px 10px;
  border-radius: 980px;
  pointer-events: none;
  letter-spacing: 0.1px;
  border: 1px solid var(--border-soft);
}

/* ── CONTROL PANEL ──────────────────────────────────────────── */
.control-panel {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

/* Controls group — Apple Settings panel feel */
.controls-group {
  background: var(--surface-raised);
  border: 1px solid var(--border-soft);
  border-radius: var(--radius-lg);
  padding: 20px 20px 4px;
  box-shadow: var(--shadow-xs);
}
.controls-title {
  font-size: 11px;
  font-weight: 600;
  color: var(--text-tertiary);
  text-transform: uppercase;
  letter-spacing: 0.7px;
  margin-bottom: 16px;
}

/* Control row */
.control-row {
  margin-bottom: 18px;
}
.control-row:last-child { margin-bottom: 4px; }

.control-label {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 13px;
  color: var(--text-secondary);
  margin-bottom: 9px;
  font-weight: 400;
}

/* Variable symbol pill */
.var-symbol {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 20px;
  height: 20px;
  background: var(--accent-subtle);
  border-radius: 5px;
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 600;
  color: var(--accent);
}

/* Calculated badge */
.calc-badge {
  font-size: 10px;
  background: rgba(52, 199, 89, 0.1);
  color: #248a3d;
  border: 1px solid rgba(52, 199, 89, 0.2);
  padding: 2px 7px;
  border-radius: 980px;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.4px;
}

.input-row {
  display: grid;
  grid-template-columns: 1fr 72px;
  gap: 10px;
  align-items: center;
}

/* Range — iOS-style track */
input[type="range"] {
  -webkit-appearance: none;
  appearance: none;
  width: 100%;
  height: 4px;
  border-radius: 2px;
  background: var(--surface-inset);
  border: none;
  outline: none;
  cursor: pointer;
}
input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 20px;
  height: 20px;
  border-radius: 50%;
  background: #ffffff;
  border: none;
  box-shadow: 0 1px 4px rgba(0,0,0,0.22), 0 0 0 0.5px rgba(0,0,0,0.08);
  cursor: pointer;
  transition: transform var(--transition);
}
input[type="range"]::-webkit-slider-thumb:hover {
  transform: scale(1.1);
}
input[type="range"]::-webkit-slider-thumb:active {
  transform: scale(0.96);
}
input[type="range"]::-moz-range-thumb {
  width: 20px;
  height: 20px;
  border-radius: 50%;
  background: #ffffff;
  border: none;
  box-shadow: 0 1px 4px rgba(0,0,0,0.22);
  cursor: pointer;
}

/* Number input */
input[type="number"] {
  background: var(--surface-subtle);
  border: 1px solid var(--border-soft);
  border-radius: var(--radius-sm);
  color: var(--text-primary);
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 500;
  padding: 7px 8px;
  width: 100%;
  text-align: center;
  outline: none;
  transition: border-color var(--transition), box-shadow var(--transition);
}
input[type="number"]:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-subtle);
}
input[type="number"]::-webkit-inner-spin-button,
input[type="number"]::-webkit-outer-spin-button { opacity: 0.5; }

/* Result display — value read-out */
.result-display {
  background: var(--surface-subtle);
  border: 1px solid var(--border-soft);
  border-radius: var(--radius-sm);
  padding: 8px 12px;
  font-family: var(--font-mono);
  font-size: 16px;
  font-weight: 600;
  color: var(--accent);
  text-align: center;
}

/* ── FORMULA DISPLAY ────────────────────────────────────────── */
.formula-display {
  background: var(--surface-raised);
  border: 1px solid var(--border-soft);
  border-radius: var(--radius-lg);
  padding: 22px 20px 18px;
  box-shadow: var(--shadow-xs);
}

.formula-box {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
  justify-content: center;
  margin-bottom: 14px;
}

.formula-var {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 1px;
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--text-tertiary);
  padding: 10px 14px;
  background: var(--surface-subtle);
  border: 1px solid var(--border-soft);
  border-radius: var(--radius-sm);
  min-width: 72px;
  font-weight: 500;
}
.formula-var strong {
  font-size: 22px;
  font-weight: 700;
  color: var(--text-primary);
  line-height: 1.1;
  letter-spacing: -0.5px;
}
.formula-var small {
  font-size: 10px;
  color: var(--text-tertiary);
  font-weight: 400;
}

.formula-eq {
  font-size: 20px;
  color: var(--text-tertiary);
  font-weight: 300;
  font-family: var(--font-ui);
}

.power-display {
  text-align: center;
  font-size: 13px;
  color: var(--text-secondary);
}
.power-display strong {
  color: var(--text-primary);
  font-weight: 600;
}

/* ── RESULT CARDS ───────────────────────────────────────────── */
.result-cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(90px, 1fr));
  gap: 10px;
}

.result-card {
  background: var(--surface-raised);
  border: 1px solid var(--border-soft);
  border-radius: var(--radius-md);
  padding: 14px 12px;
  text-align: center;
  box-shadow: var(--shadow-xs);
  transition: box-shadow var(--transition);
}
.result-card.highlight {
  border-color: rgba(0, 113, 227, 0.2);
  background: var(--accent-subtle);
}

.result-card-label {
  font-size: 10.5px;
  font-weight: 500;
  color: var(--text-tertiary);
  text-transform: uppercase;
  letter-spacing: 0.5px;
  margin-bottom: 6px;
}
.result-card-value {
  font-family: var(--font-mono);
  font-size: 18px;
  font-weight: 700;
  color: var(--text-primary);
  letter-spacing: -0.3px;
}

/* ── BUTTONS ────────────────────────────────────────────────── */
.btn-row {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
}

.action-btn {
  background: var(--accent-subtle);
  border: none;
  color: var(--accent);
  padding: 9px 18px;
  border-radius: 980px;
  font-family: var(--font-ui);
  font-size: 13px;
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition);
  white-space: nowrap;
  letter-spacing: -0.1px;
}
.action-btn:hover {
  background: var(--accent-subtle-h);
}
.action-btn:active {
  transform: scale(0.97);
}
.action-btn.danger {
  background: rgba(255, 59, 48, 0.08);
  color: #ff3b30;
}
.action-btn.danger:hover {
  background: rgba(255, 59, 48, 0.14);
}

/* ── MODE SELECTOR ──────────────────────────────────────────── */
.mode-selector {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 6px;
  background: var(--surface-raised);
  border: 1px solid var(--border-soft);
  border-radius: var(--radius-lg);
  padding: 6px;
  box-shadow: var(--shadow-xs);
}
.mode-btn {
  padding: 9px;
  border-radius: var(--radius-md);
  border: none;
  background: transparent;
  color: var(--text-secondary);
  font-family: var(--font-ui);
  font-size: 13.5px;
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition);
}
.mode-btn.active {
  background: var(--surface-base);
  color: var(--text-primary);
  box-shadow: var(--shadow-xs);
}

/* ── RESISTOR LIST ──────────────────────────────────────────── */
.resistor-list {
  display: flex;
  flex-direction: column;
  gap: 6px;
  background: var(--surface-raised);
  border: 1px solid var(--border-soft);
  border-radius: var(--radius-lg);
  padding: 8px;
  max-height: 240px;
  overflow-y: auto;
  box-shadow: var(--shadow-xs);
}

.resistor-item {
  display: flex;
  align-items: center;
  gap: 10px;
  background: var(--surface-subtle);
  border-radius: var(--radius-sm);
  padding: 9px 12px;
  transition: background var(--transition);
}
.resistor-item:hover { background: var(--surface-inset); }

.resistor-label {
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 600;
  color: var(--text-tertiary);
  min-width: 24px;
}
.resistor-input {
  flex: 1;
  background: var(--surface-base);
  border: 1px solid var(--border-soft);
  border-radius: 6px;
  color: var(--text-primary);
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 500;
  padding: 5px 8px;
  outline: none;
  transition: border-color var(--transition);
}
.resistor-input:focus { border-color: var(--accent); }
.resistor-unit {
  font-size: 12px;
  color: var(--text-tertiary);
  font-family: var(--font-mono);
}
.resistor-remove {
  background: transparent;
  border: none;
  color: var(--text-tertiary);
  cursor: pointer;
  font-size: 16px;
  padding: 2px 4px;
  border-radius: 4px;
  transition: all var(--transition);
  line-height: 1;
}
.resistor-remove:hover {
  color: #ff3b30;
  background: rgba(255, 59, 48, 0.08);
}

/* ── CHARGE CONTROLS ────────────────────────────────────────── */
.charge-type-selector {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 6px;
  margin-bottom: 16px;
  background: var(--surface-subtle);
  padding: 5px;
  border-radius: var(--radius-md);
}
.charge-btn {
  padding: 8px;
  border-radius: var(--radius-sm);
  border: none;
  background: transparent;
  font-family: var(--font-ui);
  font-size: 13px;
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition);
  color: var(--text-secondary);
}
.charge-btn.positive.active {
  background: var(--surface-base);
  color: var(--charge-pos);
  box-shadow: var(--shadow-xs);
}
.charge-btn.negative.active {
  background: var(--surface-base);
  color: var(--charge-neg);
  box-shadow: var(--shadow-xs);
}
.charge-btn:not(.active):hover {
  background: var(--surface-inset);
  color: var(--text-primary);
}

/* Charge list */
.charge-list {
  display: flex;
  flex-direction: column;
  gap: 5px;
  background: var(--surface-raised);
  border: 1px solid var(--border-soft);
  border-radius: var(--radius-lg);
  padding: 8px;
  max-height: 160px;
  overflow-y: auto;
  min-height: 52px;
  box-shadow: var(--shadow-xs);
}
.charge-item {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 12.5px;
  padding: 7px 10px;
  background: var(--surface-subtle);
  border-radius: var(--radius-sm);
  transition: background var(--transition);
}
.charge-item:hover { background: var(--surface-inset); }

.charge-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  flex-shrink: 0;
}
.charge-dot.pos { background: var(--charge-pos); }
.charge-dot.neg { background: var(--charge-neg); }
.charge-info {
  flex: 1;
  font-family: var(--font-mono);
  color: var(--text-secondary);
  font-size: 12px;
}
.charge-remove {
  background: transparent;
  border: none;
  color: var(--text-tertiary);
  cursor: pointer;
  font-size: 14px;
  padding: 2px 4px;
  border-radius: 4px;
  transition: all var(--transition);
  line-height: 1;
}
.charge-remove:hover {
  color: #ff3b30;
  background: rgba(255, 59, 48, 0.08);
}

/* View controls — toggle list */
.view-controls {
  display: flex;
  flex-direction: column;
  background: var(--surface-raised);
  border: 1px solid var(--border-soft);
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-xs);
}
.view-controls label {
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: 13.5px;
  color: var(--text-primary);
  cursor: pointer;
  padding: 12px 16px;
  transition: background var(--transition);
  border-bottom: 1px solid var(--border-soft);
  font-weight: 400;
}
.view-controls label:last-child { border-bottom: none; }
.view-controls label:hover { background: var(--surface-subtle); }
.view-controls input[type="checkbox"] {
  width: 16px;
  height: 16px;
  cursor: pointer;
  accent-color: var(--accent);
  margin-left: auto;
  order: 2;
}
.view-controls label span,
.view-controls label { flex-direction: row; }

/* ── LAMP INDICATOR ─────────────────────────────────────────── */
.lamp-indicator {
  background: var(--surface-raised);
  border: 1px solid var(--border-soft);
  border-radius: var(--radius-lg);
  padding: 22px 20px;
  text-align: center;
  box-shadow: var(--shadow-xs);
}
.lamp-bulb {
  font-size: 0;       /* Hide emoji completely */
  width: 44px;
  height: 44px;
  margin: 0 auto 10px;
  border-radius: 50%;
  background: var(--surface-inset);
  border: 2px solid var(--border-soft);
  transition: all 0.35s ease;
  position: relative;
}
.lamp-bulb.on {
  background: #ffd60a;
  border-color: #ffc300;
  box-shadow: 0 0 0 6px rgba(255, 214, 10, 0.15), 0 4px 16px rgba(255, 196, 0, 0.3);
}
.lamp-label {
  font-size: 11px;
  font-weight: 500;
  color: var(--text-tertiary);
  margin-bottom: 12px;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}
.lamp-bar {
  height: 4px;
  background: var(--surface-inset);
  border-radius: 2px;
  overflow: hidden;
}
.lamp-fill {
  height: 100%;
  background: #ffd60a;
  border-radius: 2px;
  transition: width 0.3s ease;
  width: 0%;
}

/* ── CLASSROOM INFO ─────────────────────────────────────────── */
.classroom-info {
  background: var(--surface-raised);
  border: 1px solid var(--border-soft);
  border-radius: var(--radius-lg);
  padding: 20px;
  animation: moduleFadeIn 0.25s ease;
  box-shadow: var(--shadow-xs);
}
.classroom-info.hidden { display: none; }

.classroom-info h4 {
  font-size: 12px;
  font-weight: 600;
  color: var(--text-tertiary);
  text-transform: uppercase;
  letter-spacing: 0.6px;
  margin-bottom: 14px;
}
.classroom-info p {
  font-size: 13.5px;
  color: var(--text-secondary);
  line-height: 1.65;
  margin-bottom: 10px;
}
.classroom-info p:last-child { margin-bottom: 0; }
.classroom-info strong {
  color: var(--text-primary);
  font-weight: 500;
}
.classroom-example {
  background: var(--surface-subtle);
  border-left: 2px solid var(--border-medium);
  padding: 10px 14px;
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  font-style: normal;
  margin-top: 12px !important;
  font-size: 13px;
  color: var(--text-secondary);
}

/* Interaction type */
#interaction-type.atracao  { color: var(--accent); }
#interaction-type.repulsao { color: #ff9500; }

/* ── FOOTER ─────────────────────────────────────────────────── */
.site-footer {
  border-top: 1px solid var(--border-soft);
  padding: 22px 32px;
  text-align: center;
  font-size: 12.5px;
  color: var(--text-tertiary);
}
.site-footer strong { color: var(--text-secondary); font-weight: 500; }
.site-footer a {
  color: var(--accent);
  text-decoration: none;
  margin-left: 6px;
  font-weight: 500;
}
.site-footer a:hover { text-decoration: underline; }

/* ── UTILITY ─────────────────────────────────────────────────── */
.hidden { display: none !important; }

/* Field info wrapper */
.field-info { /* pass-through */ }