/* ── Reset & Base ── */
* { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --bg:        #0d1117;
  --panel:     #161b22;
  --border:    #30363d;
  --text:      #e6edf3;
  --muted:     #8b949e;
  --accent:    #58a6ff;
  --green:     #3fb950;
  --red:       #f85149;
  --yellow:    #d29922;
  --radius:    12px;

  /* cores das funções */
  --fn-0: #58a6ff;   /* linear     — azul    */
  --fn-1: #f78166;   /* quadrática — laranja */
  --fn-2: #56d364;   /* seno       — verde   */
  --fn-3: #bc8cff;   /* cosseno    — roxo    */
  --fn-4: #ff7b72;   /* exponencial— vermelho*/
  --fn-5: #ffa657;   /* ReLU       — âmbar   */
  --fn-6: #79c0ff;   /* degrau     — azul cl.*/
  --fn-sum: #ffffff; /* soma       — branco  */
}

body {
  font-family: 'Segoe UI', system-ui, sans-serif;
  background: var(--bg);
  color: var(--text);
  height: 100vh;
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

/* ── Header ── */
#header {
  display: flex; align-items: center; justify-content: space-between;
  padding: 10px 20px;
  background: var(--panel);
  border-bottom: 1px solid var(--border);
  flex-shrink: 0;
}
#header-left  { display: flex; align-items: center; gap: 12px; }
#back-btn {
  color: var(--muted); text-decoration: none;
  font-size: 13px; padding: 4px 10px;
  border: 1px solid var(--border); border-radius: 6px;
  transition: color .2s, border-color .2s;
}
#back-btn:hover { color: var(--text); border-color: var(--accent); }
#header-title  { font-size: 1rem; font-weight: 700; }
#header-badge  {
  font-size: .7rem; color: var(--muted);
  background: #21262d; padding: 3px 10px;
  border-radius: 20px; border: 1px solid var(--border);
}

/* ── Botões globais ── */
.btn-ghost {
  background: transparent; color: var(--muted);
  border: 1px solid var(--border); border-radius: 6px;
  padding: 6px 12px; font-size: .82rem;
  cursor: pointer; transition: color .2s, border-color .2s;
}
.btn-ghost:hover { color: var(--text); border-color: var(--muted); }
.hidden { display: none !important; }

/* ── App wrapper ── */
#app {
  display: flex;
  flex-direction: column;
  height: 100vh;
  overflow: hidden;
}

/* ── Layout principal ── */
#main-layout {
  flex: 1;
  display: flex;
  overflow: hidden;
}

/* ══════════════════════════════════
   COLUNA ESQUERDA — GRÁFICO
══════════════════════════════════ */
#canvas-col {
  flex: 1;
  min-width: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 20px;
  gap: 12px;
  position: relative;
}

#canvas-wrap {
  position: relative;
  width: 100%;
  max-width: 860px;
  aspect-ratio: 16 / 9;
  border-radius: var(--radius);
  overflow: hidden;
  border: 2px solid var(--border);
  background: #0a0e14;
}

#canvas-main {
  width: 100%;
  height: 100%;
  display: block;
}

/* Tooltip */
#tooltip {
  position: absolute;
  background: rgba(22,27,34,.92);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 6px 12px;
  font-size: .78rem;
  color: var(--text);
  pointer-events: none;
  white-space: nowrap;
  z-index: 10;
}

/* Legenda da soma */
#sum-legend {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: .82rem;
  color: var(--muted);
}
.sum-line {
  display: inline-block;
  width: 32px; height: 3px;
  background: var(--fn-sum);
  border-radius: 2px;
  flex-shrink: 0;
}
#sum-label { color: var(--text); }
#sum-formula { color: var(--accent); font-family: monospace; font-size: .85rem; }

/* ══════════════════════════════════
   COLUNA DIREITA — CONTROLES
══════════════════════════════════ */
#controls-col {
  width: 320px;
  flex-shrink: 0;
  border-left: 1px solid var(--border);
  background: var(--panel);
  overflow-y: auto;
  display: flex;
  flex-direction: column;
}

#intro-blurb {
  padding: 12px 16px;
  font-size: .78rem;
  color: var(--muted);
  line-height: 1.6;
  border-bottom: 1px solid var(--border);
}

.ctrl-section {
  padding: 14px 16px;
  border-bottom: 1px solid var(--border);
  display: flex;
  flex-direction: column;
  gap: 10px;
  flex-shrink: 0;
}
.ctrl-title {
  font-size: .75rem; font-weight: 700;
  text-transform: uppercase; letter-spacing: .06em;
  color: var(--muted);
}

/* ── Cartões de função ── */
#fn-list {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.fn-card {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 10px 12px;
  display: flex;
  flex-direction: column;
  gap: 8px;
  transition: border-color .2s, background .2s;
}
.fn-card.active {
  border-color: var(--fn-color, var(--accent));
  background: color-mix(in srgb, var(--fn-color, var(--accent)) 8%, var(--bg));
}

.fn-header {
  display: flex;
  align-items: center;
  gap: 10px;
}

/* Toggle switch */
.fn-toggle {
  position: relative;
  width: 36px; height: 20px;
  flex-shrink: 0;
}
.fn-toggle input { opacity: 0; width: 0; height: 0; }
.fn-toggle-track {
  position: absolute; inset: 0;
  background: var(--border);
  border-radius: 20px;
  cursor: pointer;
  transition: background .2s;
}
.fn-toggle input:checked + .fn-toggle-track {
  background: var(--fn-color, var(--accent));
}
.fn-toggle-thumb {
  position: absolute;
  top: 3px; left: 3px;
  width: 14px; height: 14px;
  background: #fff;
  border-radius: 50%;
  transition: transform .2s;
  pointer-events: none;
}
.fn-toggle input:checked ~ .fn-toggle-thumb { transform: translateX(16px); }

.fn-color-dot {
  width: 10px; height: 10px;
  border-radius: 50%;
  flex-shrink: 0;
  background: var(--fn-color, var(--muted));
}
.fn-name {
  flex: 1;
  font-size: .85rem; font-weight: 600;
}
.fn-formula {
  font-size: .72rem; color: var(--muted);
  font-family: monospace;
}

/* Sliders por parâmetro */
.fn-params {
  display: flex;
  flex-direction: column;
  gap: 6px;
}
.fn-param-row {
  display: flex;
  align-items: center;
  gap: 8px;
}
.fn-param-label {
  font-size: .72rem;
  color: var(--muted);
  width: 14px;
  text-align: center;
  font-family: monospace;
}
.fn-param-slider {
  flex: 1;
  accent-color: var(--fn-color, var(--accent));
  height: 3px;
  cursor: pointer;
}
.fn-param-val {
  font-size: .72rem;
  color: var(--text);
  min-width: 36px;
  text-align: right;
  font-family: monospace;
}

/* ── Hint pedagógico ── */
#pedagogy-hint {
  font-size: .78rem;
  color: var(--muted);
  line-height: 1.6;
  padding: 8px 10px;
  background: rgba(88,166,255,.06);
  border: 1px solid rgba(88,166,255,.15);
  border-radius: 8px;
}
#pedagogy-hint strong { color: var(--text); }

/* ── Desafios ── */
#challenge-list {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 6px;
}
.challenge-btn {
  background: var(--bg);
  border: 1px solid var(--border);
  color: var(--muted);
  border-radius: 8px;
  padding: 9px 8px;
  font-size: .75rem; font-weight: 600;
  cursor: pointer;
  text-align: center;
  transition: border-color .2s, color .2s, background .2s;
}
.challenge-btn:hover  { border-color: var(--accent); color: var(--text); background: rgba(88,166,255,.07); }
.challenge-btn.active { border-color: var(--yellow); color: var(--yellow); background: rgba(210,153,34,.08); }

/* ── Barra de adicionar funções ── */
#add-bar {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

.add-fn-btn {
  background: color-mix(in srgb, var(--fn-color, var(--accent)) 12%, var(--bg));
  border: 1px solid color-mix(in srgb, var(--fn-color, var(--accent)) 40%, transparent);
  color: var(--fn-color, var(--accent));
  border-radius: 20px;
  padding: 5px 12px;
  font-size: .75rem;
  font-weight: 600;
  cursor: pointer;
  transition: background .15s, transform .1s;
  white-space: nowrap;
}
.add-fn-btn:hover {
  background: color-mix(in srgb, var(--fn-color, var(--accent)) 22%, var(--bg));
  transform: scale(1.04);
}

/* ── Empty hint ── */
#empty-hint {
  font-size: .76rem;
  color: var(--muted);
  text-align: center;
  padding: 10px 0;
  font-style: italic;
}

/* ── Botão remover bloco ── */
.btn-remove {
  margin-left: auto;
  background: transparent;
  border: none;
  color: var(--muted);
  font-size: 1rem;
  line-height: 1;
  cursor: pointer;
  padding: 2px 4px;
  border-radius: 4px;
  transition: color .15s, background .15s;
}
.btn-remove:hover { color: var(--red); background: rgba(248,81,73,.1); }

/* ── Range (xMin/xMax) dentro do bloco ── */
.fn-range {
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding-top: 4px;
  border-top: 1px dashed var(--border);
  margin-top: 2px;
}

.range-label {
  width: 36px !important;
  font-size: .65rem !important;
  color: var(--muted);
}

.range-slider {
  accent-color: var(--muted) !important;
}

/* ── Legenda: linha alvo ── */
.target-line {
  display: inline-block;
  width: 32px; height: 3px;
  background: repeating-linear-gradient(
    to right,
    #d29922 0px, #d29922 8px,
    transparent 8px, transparent 13px
  );
  flex-shrink: 0;
  vertical-align: middle;
}
#target-label {
  font-size: .76rem;
  color: #d29922;
}

/* ── Dica do desafio ── */
.btn-hint-toggle {
  background: none;
  border: none;
  color: #d29922;
  font-size: .78rem;
  cursor: pointer;
  padding: 2px 0;
  opacity: .8;
  transition: opacity .15s;
}
.btn-hint-toggle:hover { opacity: 1; }

.hint-body {
  font-size: .78rem;
  color: var(--muted);
  line-height: 1.6;
  padding: 8px 10px;
  margin-top: 6px;
  background: rgba(210,153,34,.06);
  border: 1px solid rgba(210,153,34,.2);
  border-radius: 8px;
}

/* ── Ações do desafio ── */
#challenge-actions {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
}

.btn-check {
  flex: 1;
  background: rgba(88,166,255,.12);
  border: 1px solid var(--accent);
  color: var(--accent);
  border-radius: 8px;
  padding: 8px 12px;
  font-size: .82rem;
  font-weight: 700;
  cursor: pointer;
  transition: background .15s;
}
.btn-check:hover { background: rgba(88,166,255,.22); }

/* ── Score ── */
.challenge-score {
  font-size: .82rem;
  font-weight: 700;
  padding: 8px 12px;
  border-radius: 8px;
  text-align: center;
}
.challenge-score.pass {
  background: rgba(63,185,80,.12);
  border: 1px solid #3fb950;
  color: #3fb950;
}
.challenge-score.fail {
  background: rgba(248,81,73,.1);
  border: 1px solid var(--red);
  color: var(--red);
}

/* ── Responsividade ── */
@media (max-width: 700px) {
  #main-layout   { flex-direction: column; }
  #controls-col  { width: 100%; border-left: none; border-top: 1px solid var(--border); max-height: 48vh; }
  #canvas-col    { padding: 10px; justify-content: flex-start; }
}