*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --bg:        #f5f4f0;
  --surface:   #ffffff;
  --surface2:  #f0ede6;
  --border:    #d4cfc5;
  --border2:   #e8e4dc;
  --text:      #1a1814;
  --text2:     #4a4640;
  --text3:     #7a756e;
  --accent:    #0d9488;
  --accent-dim:#0f766e;
  --amber:     #5eead4;
  --mono:      'IBM Plex Mono', monospace;
  --sans:      'IBM Plex Sans', sans-serif;
  --display:   'Playfair Display', serif;
  --radius:    4px;
}

body {
  font-family: var(--sans);
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
  line-height: 1.5;
}

/* ── HEADER ── */
.site-header {
  background: var(--accent);
  border-bottom: 3px solid var(--amber);
  padding: 0 2rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 56px;
  gap: 0.5rem;
  flex-wrap: wrap;
}

.logo-link {
  text-decoration: none;
  display: flex;
  align-items: center;
  gap: 0.75rem;
  transition: opacity 0.2s;
  color: inherit;
}
.logo-link:hover { opacity: 0.85; }

.logo-img { height: 44px; width: auto; display: block; }

.logo-text {
  font-family: var(--display);
  color: #fff;
  font-size: 1.1rem;
  letter-spacing: 0.01em;
  display: flex;
  flex-direction: column;
}
.logo-text span {
  font-family: var(--mono);
  color: var(--amber);
  font-size: 0.68rem;
  font-weight: 500;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  margin-top: -2px;
}

.header-badges { display: flex; align-items: center; gap: 0.5rem; }
.header-badge {
  background: rgba(255,255,255,0.12);
  border: 1px solid rgba(255,255,255,0.22);
  color: rgba(255,255,255,0.85);
  font-family: var(--mono);
  font-size: 0.68rem;
  padding: 3px 10px;
  border-radius: 2px;
  letter-spacing: 0.08em;
}

/* ── LAYOUT ── */
.app {
  display: flex;
  height: calc(100vh - 59px);
  overflow: hidden;
}

/* ── SIDEBAR ── */
.sidebar {
  width: 272px;
  min-width: 272px;
  background: var(--surface);
  border-right: 1px solid var(--border);
  overflow-y: auto;
  display: flex;
  flex-direction: column;
}

.sidebar-section { border-bottom: 1px solid var(--border2); }

.section-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 9px 14px;
  cursor: pointer;
  user-select: none;
  background: var(--surface2);
}
.section-header:hover { background: var(--border2); }

.section-header h3 {
  font-family: var(--mono);
  font-size: 0.70rem;
  font-weight: 600;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--text2);
}

.toggle-icon {
  font-size: 0.65rem;
  color: var(--text3);
  transition: transform 0.2s;
}
.section-header.collapsed .toggle-icon { transform: rotate(-90deg); }

.section-body { padding: 10px 14px; display: flex; flex-direction: column; gap: 8px; }
.section-body.hidden { display: none; }

/* ── FIELDS ── */
.field { display: flex; flex-direction: column; gap: 4px; }

.field label {
  font-size: 0.77rem;
  font-weight: 500;
  color: var(--text2);
  display: flex;
  align-items: center;
  gap: 4px;
}
.field label em {
  font-style: normal;
  font-family: var(--mono);
  font-size: 0.82rem;
  color: var(--accent);
}
.field label .unit {
  font-family: var(--mono);
  font-size: 0.67rem;
  color: var(--text3);
  margin-left: auto;
}

.slider-row { display: flex; align-items: center; gap: 6px; }

input[type="range"] { flex: 1; height: 4px; accent-color: var(--accent); cursor: pointer; }

.num-input {
  width: 60px;
  font-family: var(--mono);
  font-size: 0.74rem;
  text-align: right;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 3px 6px;
  background: var(--surface2);
  color: var(--text);
  outline: none;
}
.num-input:focus { border-color: var(--accent); }

/* ── PRESETS ── */
.btn-preset {
  background: var(--surface2);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 6px 10px;
  font-family: var(--mono);
  font-size: 0.72rem;
  color: var(--text2);
  cursor: pointer;
  text-align: left;
  transition: all 0.15s;
}
.btn-preset:hover { background: var(--border2); border-color: var(--accent); color: var(--accent); }
.btn-preset.active { background: var(--accent); border-color: var(--accent); color: #fff; }

/* ── BUTTONS ── */
.btn-primary {
  background: var(--accent);
  border: none;
  border-radius: var(--radius);
  padding: 7px 12px;
  font-family: var(--mono);
  font-size: 0.75rem;
  font-weight: 600;
  color: #fff;
  cursor: pointer;
  transition: background 0.15s;
}
.btn-primary:hover { background: var(--accent-dim); }

.btn-secondary {
  background: var(--surface2);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 7px 12px;
  font-family: var(--mono);
  font-size: 0.75rem;
  color: var(--text2);
  cursor: pointer;
  transition: all 0.15s;
}
.btn-secondary:hover { border-color: var(--accent); color: var(--accent); }

.controls-body { gap: 6px !important; }

/* ── EQUATION DISPLAY ── */
.eq-section-body { padding: 8px 10px !important; }

.eq-container {
  background: #070b12;
  border-radius: 3px;
  padding: 10px 12px;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.eq-type-badge {
  font-family: var(--mono);
  font-size: 0.60rem;
  color: #4a5878;
  text-transform: uppercase;
  letter-spacing: 0.09em;
  padding-bottom: 6px;
  border-bottom: 1px solid rgba(255,255,255,0.05);
}

.eq-formula { display: flex; flex-direction: column; gap: 3px; }

.eq-row {
  display: flex;
  align-items: baseline;
  gap: 4px;
  min-height: 22px;
}

.eq-lhs {
  font-family: var(--mono);
  font-size: 0.88rem;
  color: #a5b4fc;
  white-space: nowrap;
  min-width: 32px;
}

.eq-indent { min-width: 32px; display: inline-block; }

.eq-t1 { font-family: var(--mono); font-size: 0.78rem; color: #3dd6f5; white-space: nowrap; }
.eq-t2 { font-family: var(--mono); font-size: 0.78rem; color: #f87171; white-space: nowrap; }
.eq-t3 { font-family: var(--mono); font-size: 0.78rem; color: #fbbf24; white-space: nowrap; }

.eq-tag {
  font-family: var(--mono);
  font-size: 0.57rem;
  letter-spacing: 0.05em;
  margin-left: auto;
  opacity: 0.55;
  white-space: nowrap;
}
.t1-tag { color: #3dd6f5; }
.t2-tag { color: #f87171; }
.t3-tag { color: #fbbf24; }

.eq-params {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 3px 8px;
  padding-top: 7px;
  border-top: 1px solid rgba(255,255,255,0.05);
}

.eq-param {
  font-family: var(--mono);
  font-size: 0.68rem;
  color: #3a4a60;
}
.eq-param span { color: #7c8fa8; }
.eq-param.eq-t1 span { color: #3dd6f5; }
.eq-param.eq-t2 span { color: #f87171; }
.eq-param.eq-t3 span { color: #fbbf24; }
.eq-param.eq-t2, .eq-param.eq-t3 { color: #3a4a60; }

/* ── INFO ROWS ── */
.info-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.71rem;
  font-family: var(--mono);
  color: var(--text3);
  min-height: 18px;
}
.info-row span:first-child { color: var(--text2); }
.info-row span:last-child  { color: var(--accent); font-weight: 500; }
.info-row.separator        { height: 1px; background: var(--border2); margin: 2px 0; }

/* ── MAIN AREA ── */
.main-area {
  flex: 1;
  overflow: auto;
  padding: 10px;
  display: grid;
  grid-template-columns: 1fr 1fr;
  grid-template-rows: 1fr auto;
  gap: 8px;
  min-height: 0;
}

/* ── PANELS ── */
.panel {
  background: #080c14;
  border-radius: 4px;
  overflow: hidden;
  position: relative;
  display: flex;
  flex-direction: column;
  min-height: 0;
}

.panel-label {
  position: absolute;
  top: 7px;
  left: 10px;
  font-family: var(--mono);
  font-size: 0.60rem;
  letter-spacing: 0.1em;
  color: #3a5a72;
  text-transform: uppercase;
  pointer-events: none;
  z-index: 1;
}

.panel canvas {
  display: block;
  width: 100%;
  height: 100%;
  flex: 1;
  min-height: 0;
}

.panel-pendulum { grid-row: 1; grid-column: 1; min-height: 320px; }
.panel-graph    { grid-row: 1; grid-column: 2; min-height: 320px; }
.panel-energy   { grid-row: 2; grid-column: 1 / 3; height: 138px; }

/* ── GRAPH TABS ── */
.graph-tabs {
  display: flex;
  gap: 3px;
  padding: 6px 8px;
  background: #060a10;
  flex-shrink: 0;
  flex-wrap: wrap;
  border-bottom: 1px solid rgba(255,255,255,0.05);
}

.graph-tab {
  background: rgba(255,255,255,0.04);
  border: 1px solid rgba(255,255,255,0.08);
  color: #4a5878;
  font-family: var(--mono);
  font-size: 0.62rem;
  padding: 4px 9px;
  border-radius: 2px;
  cursor: pointer;
  transition: all 0.15s;
  white-space: nowrap;
}
.graph-tab:hover { border-color: rgba(255,255,255,0.2); color: #8899cc; }
.graph-tab.active {
  background: rgba(13,148,136,0.30);
  border-color: rgba(13,148,136,0.70);
  color: #99f6e4;
}

/* ── SCROLLBAR ── */
.sidebar::-webkit-scrollbar { width: 5px; }
.sidebar::-webkit-scrollbar-track { background: transparent; }
.sidebar::-webkit-scrollbar-thumb { background: var(--border); border-radius: 3px; }

/* ── FORCES TOGGLE (modo 3 do gráfico) ── */
.forces-toggle {
  display: none;
  gap: 4px;
  padding: 5px 8px;
  background: #040710;
  border-bottom: 1px solid rgba(255,255,255,0.05);
  flex-wrap: wrap;
  flex-shrink: 0;
}
.forces-toggle.visible { display: flex; }
.force-btn {
  background: rgba(255,255,255,0.03);
  border: 1px solid rgba(255,255,255,0.08);
  color: #3a4a60;
  font-family: var(--mono);
  font-size: 0.60rem;
  padding: 3px 8px;
  border-radius: 2px;
  cursor: pointer;
  transition: all 0.15s;
  white-space: nowrap;
}
.force-btn.force-rest.active { border-color: rgba(61,214,245,0.5);  background: rgba(61,214,245,0.08);  color: #3dd6f5; }
.force-btn.force-damp.active { border-color: rgba(248,113,113,0.5); background: rgba(248,113,113,0.08); color: #f87171; }
.force-btn.force-driv.active { border-color: rgba(251,191,36,0.5);  background: rgba(251,191,36,0.08);  color: #fbbf24; }

/* ── STEP BUTTONS ROW ── */
.btn-row { display: flex; gap: 6px; }
.btn-row .btn-secondary { flex: 1; text-align: center; }
.btn-secondary:disabled { opacity: 0.3; cursor: not-allowed; }
.btn-secondary:disabled:hover { border-color: var(--border); color: var(--text2); }

/* ── MOBILE TOGGLE BUTTON (hidden on desktop) ── */
.mobile-toggle-btn { display: none; }

/* ══════════════════════════════════════════════
   RESPONSIVE — painéis empilhados (≤ 860px)
   Ordem: [toggle] → [sidebar] → [animação] → [gráfico] → [energia]
   ══════════════════════════════════════════════ */
@media (max-width: 860px) {

  body { overflow-y: auto; }

  /* Header: altura fixa → automática para badges não serem cortadas */
  .site-header {
    height: auto;
    min-height: 56px;
    padding-block: 8px;
  }

  .app {
    flex-direction: column;
    height: auto;
    overflow: visible;
  }

  /* Botão toggle — visível apenas em mobile */
  .mobile-toggle-btn {
    display: flex;
    align-items: center;
    gap: 8px;
    width: 100%;
    padding: 10px 14px;
    background: var(--surface2);
    border: none;
    border-bottom: 1px solid var(--border);
    font-family: var(--mono);
    font-size: 0.78rem;
    font-weight: 600;
    color: var(--text2);
    cursor: pointer;
    letter-spacing: 0.04em;
    text-transform: uppercase;
    flex-shrink: 0;
  }
  .mobile-toggle-btn:hover { background: var(--border2); }
  .mobile-toggle-btn.open  { color: var(--accent); border-bottom-color: var(--accent); }

  /* Sidebar: oculta por padrão, desliza para baixo quando aberta */
  .sidebar {
    width: 100%;
    min-width: unset;
    border-right: none;
    border-bottom: 1px solid var(--border);
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.35s ease;
  }
  .sidebar.mobile-open {
    max-height: 80vh;
    overflow-y: auto;
  }

  /* Grid de painéis: coluna única */
  .main-area {
    grid-template-columns: 1fr;
    grid-template-rows: auto auto auto;
    height: auto;
    overflow: visible;
    flex: none;
    padding: 6px;
  }

  .panel-pendulum {
    grid-row: 1;
    grid-column: 1;
    min-height: 300px;
    height: 44vw;
    max-height: 420px;
  }

  .panel-graph {
    grid-row: 2;
    grid-column: 1;
    min-height: 280px;
    height: 42vw;
    max-height: 400px;
  }

  .panel-energy {
    grid-row: 3;
    grid-column: 1;
    height: 160px;
  }
}

/* ── Telas muito pequenas (≤ 480px) ── */
@media (max-width: 480px) {
  .site-header { padding: 0 1rem; }
  .header-badges { flex-wrap: wrap; }
  .panel-pendulum { height: 56vw; max-height: 340px; }
  .panel-graph    { height: 52vw; max-height: 320px; }
}