:root {
  color-scheme: light;
  --green: #83c44e;
  --dark: #619b60;
  --gray: #6f7171;
  --muted: #66726d;
  --paper: #f6f8f4;
  --line: #d9dfda;
  --ink: #26312d;
}
* { box-sizing: border-box; }
body { margin: 0; min-width: 320px; color: var(--ink); background: var(--paper); font-family: Ubuntu, system-ui, sans-serif; }
button, input, select { font: inherit; }
.skip-link { position: fixed; left: 8px; top: -50px; z-index: 20; padding: 8px; background: var(--ink); color: #fff; }
.skip-link:focus { top: 8px; }
button:focus-visible, input:focus-visible, select:focus-visible { outline: 3px solid var(--green); outline-offset: 2px; }
.app-shell { width: min(1800px, 100%); margin: auto; padding: 20px; }
.topbar { display: grid; grid-template-columns: 230px 1fr 245px; align-items: end; gap: 24px; padding: 8px 4px 22px; }
.brand { display: grid; line-height: 1; color: var(--dark); }
.brand b { font-size: .9rem; letter-spacing: .06em; }
.brand small { margin-top: 5px; color: var(--gray); font-size: .62rem; letter-spacing: .12em; }
.eyebrow { margin: 0 0 5px; color: var(--dark); font-size: .74rem; font-weight: 800; letter-spacing: .16em; text-transform: uppercase; }
h1 { margin: 0; font-size: clamp(2rem, 3.4vw, 3.4rem); line-height: .98; letter-spacing: -.035em; text-transform: uppercase; }
.subtitle { margin: 7px 0 0; color: var(--muted); }
.status { padding: 12px 14px; border: 1px solid var(--line); border-left: 4px solid var(--green); border-radius: 8px; background: #fff; }
.status span, .status small { display: block; color: var(--muted); font-size: .7rem; }
.status strong { display: block; margin: 4px 0; }
.tabs { display: grid; grid-template-columns: repeat(3, 1fr); gap: 8px; margin-bottom: 10px; }
.tabs button { display: flex; align-items: center; gap: 11px; min-height: 58px; padding: 9px 14px; border: 1px solid var(--line); border-radius: 8px; background: #fff; color: var(--muted); text-align: left; cursor: pointer; }
.tabs button.active { border-color: var(--dark); background: #f4faef; box-shadow: inset 0 -3px var(--green); }
.tabs b { color: var(--dark); font-size: 1.15rem; }
.tabs span { font-size: .78rem; line-height: 1.15; }
.workspace { display: grid; grid-template-columns: 285px minmax(480px, 1fr) 300px; align-items: start; gap: 10px; }
.stage { display: flex; min-width: 0; flex-direction: column; gap: 10px; }
.controls, .canvas-panel, .analysis { border: 1px solid var(--line); border-radius: 10px; background: #fff; box-shadow: 0 7px 24px rgba(45, 62, 53, .05); }
.controls, .analysis { padding: 16px; }
.panel-title, .chart-heading { display: flex; align-items: center; justify-content: space-between; gap: 12px; }
.panel-title { padding-bottom: 12px; border-bottom: 1px solid var(--line); }
h2 { margin: 0; color: var(--gray); font-size: .74rem; letter-spacing: .12em; text-transform: uppercase; }
#resetBtn { padding: 5px 8px; border: 1px solid var(--line); border-radius: 5px; background: #fff; color: var(--muted); font-size: .7rem; cursor: pointer; }
.view-controls { display: none; }
.view-controls.active { display: block; }
.view-controls h3 { margin: 18px 0 10px; }
.view-controls label { display: grid; grid-template-columns: 1fr auto; gap: 6px; margin: 14px 0; }
.view-controls label span, .view-controls output { font-size: .72rem; }
.view-controls output { color: var(--dark); font-weight: 700; }
.view-controls input { grid-column: 1 / -1; width: 100%; accent-color: var(--dark); }
.action-bar { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 7px; margin-top: 18px; }
.action-bar:empty { display: none; }
.action-bar button { min-height: 35px; padding: 7px; border: 1px solid var(--dark); border-radius: 6px; background: var(--dark); color: #fff; font-size: .7rem; cursor: pointer; }
.action-bar button.quiet { border-color: var(--line); background: #fff; color: var(--muted); }
.state-select { grid-column: 1 / -1; display: grid; gap: 6px; color: var(--muted); font-size: .72rem; }
.state-select select { min-height: 36px; padding: 6px; border: 1px solid var(--line); border-radius: 6px; background: #fff; color: var(--ink); }
.canvas-panel { padding: 15px; }
.secondary-panel { box-shadow: 0 4px 14px rgba(45, 62, 53, .04); }
.chart-heading { min-height: 48px; }
.chart-heading p { margin: 4px 0; color: var(--muted); font-size: .69rem; }
canvas { display: block; width: 100%; height: auto; border-radius: 7px; background: #fbfcfa; }
.secondary-panel canvas { max-height: 260px; }
.caption { min-height: 34px; margin: 9px 3px 0; color: var(--muted); font-size: .69rem; line-height: 1.45; }
.legend { display: flex; gap: 8px; flex-wrap: wrap; font-size: .67rem; }
.legend i { display: inline-block; width: 17px; margin-right: 4px; border-top: 3px solid; vertical-align: 3px; }
.analysis { display: flex; flex-direction: column; gap: 14px; }
.analysis section { padding-bottom: 13px; border-bottom: 1px solid var(--line); }
.analysis section:last-child { border: 0; }
.predict { padding: 12px !important; border: 1px solid #e8c78f !important; border-radius: 7px; background: #fff9ef; }
.predict span { color: #a66c17; font-size: .64rem; font-weight: 800; letter-spacing: .09em; text-transform: uppercase; }
.predict p { margin: 6px 0 0; font-size: .72rem; line-height: 1.45; }
.calculation { margin-top: 9px; padding: 11px 7px; border-radius: 6px; background: #f4f7f2; font-family: Georgia, serif; line-height: 1.6; text-align: center; }
dl { margin: 8px 0; }
dl div { display: flex; justify-content: space-between; gap: 10px; padding: 6px 0; border-bottom: 1px dashed var(--line); }
dt, dd, ol { font-size: .69rem; }
dd { margin: 0; color: var(--dark); font-weight: 700; text-align: right; }
ol { padding-left: 19px; color: var(--muted); line-height: 1.45; }
ol li + li { margin-top: 6px; }
footer { display: flex; flex-wrap: wrap; justify-content: space-between; gap: 8px 18px; padding: 13px 4px; color: var(--gray); font-size: .63rem; line-height: 1.4; }

@media (max-width: 1180px) {
  .topbar { grid-template-columns: 200px 1fr; }
  .status { grid-column: 1 / -1; }
  .workspace { grid-template-columns: 270px 1fr; }
  .analysis { grid-column: 1 / -1; display: grid; grid-template-columns: repeat(3, 1fr); }
}
@media (max-width: 760px) {
  .app-shell { padding: 10px; }
  .topbar, .workspace { grid-template-columns: 1fr; }
  .status, .analysis { grid-column: auto; }
  .tabs { grid-template-columns: 1fr; }
  .analysis { display: grid; grid-template-columns: 1fr; }
}

/* ------------------------------------------------------------------ */
/* Extensões para Mecânica Clássica                                    */
/* ------------------------------------------------------------------ */

/* O número de estações varia de 2 a 5 entre as aulas. */
.tabs { grid-template-columns: repeat(auto-fit, minmax(150px, 1fr)); }

/* Painel de leituras com duas colunas quando há muitas grandezas. */
dl.wide div { flex-direction: column; align-items: flex-start; gap: 2px; }
dl.wide dd { text-align: left; }

/* Chip de regime (subamortecido, ligado, estável...) sobre o gráfico. */
.regime { display: inline-block; margin-left: 10px; padding: 3px 9px; border-radius: 20px;
  background: #eef4e8; color: var(--dark); font-size: .64rem; font-weight: 700;
  letter-spacing: .06em; text-transform: uppercase; white-space: nowrap; }
.regime[data-tone="warn"] { background: #fdf3e2; color: #a66c17; }
.regime[data-tone="alert"] { background: #fbecea; color: #b0452f; }

/* Conta aberta: destaque da linha de substituição numérica. */
.calculation b { color: var(--dark); }
.calculation em { display: block; margin-top: 5px; color: var(--muted);
  font-family: Ubuntu, system-ui, sans-serif; font-size: .66rem; font-style: normal; }

/* Correção do padrão apontado em ANALISE-LAYOUT.md: no mobile a visualização
   precede os controles, para que o gráfico apareça antes da dobra. */
@media (max-width: 760px) {
  .workspace { display: flex; flex-direction: column; }
  .stage { order: 1; }
  .controls { order: 2; }
  .analysis { order: 3; }
}

@media (prefers-reduced-motion: reduce) {
  * { animation-duration: .01ms !important; transition-duration: .01ms !important; }
}

/* Fórmula e orientação dentro do painel de controles. */
.view-controls .equation { margin: 0 0 4px; padding: 9px 8px; border-radius: 6px;
  background: #f4f7f2; color: var(--ink); font-family: Georgia, serif;
  font-size: .82rem; text-align: center; }
.view-controls .hint { margin: 14px 0 0; color: var(--muted); font-size: .68rem; line-height: 1.45; }
#secondaryPanel[hidden] { display: none; }