/* ═══════════════════════════════════════════════════════════════════
   Entrenador de funciones · Diseño v2
   ═══════════════════════════════════════════════════════════════════ */

/* ── Tokens ── */
.ef {
  --ef-ink: #eaf2ff;
  --ef-muted: #8a9bba;
  --ef-card: rgba(14, 21, 40, .72);
  --ef-card2: rgba(255, 255, 255, .04);
  --ef-line: rgba(130, 190, 255, .15);
  --ef-acc: #8b6bff;
  --ef-acc2: #5ef2e0;
  --ef-warn: #f5c04a;
  --ef-ok: #4ade80;
  --ef-bad: #fb7185;
  --ef-paper: #0b1020;
  --ef-surface: rgba(20, 28, 52, .85);
  --ef-radius: 14px;
  --ef-font-body: var(--bf-font-body, 'Inter', system-ui, sans-serif);
  --ef-font-display: var(--bf-font-display, 'Space Grotesk', 'Inter', sans-serif);
  --ef-font-mono: var(--bf-font-mono, 'JetBrains Mono', monospace);
  color: var(--ef-ink);
  max-width: 1200px;
  margin: 0 auto;
  padding: 8px 0 56px;
  font-family: var(--ef-font-body);
}

html.theme-light .ef,
body[data-theme="light"] .ef {
  --ef-ink: #101828;
  --ef-muted: #51607a;
  --ef-card: rgba(255, 255, 255, .92);
  --ef-card2: rgba(30, 40, 80, .04);
  --ef-line: rgba(30, 40, 80, .12);
  --ef-acc: #6d4df2;
  --ef-acc2: #0f9d8a;
  --ef-warn: #b7791f;
  --ef-ok: #15803d;
  --ef-bad: #be123c;
  --ef-paper: #f8fafc;
  --ef-surface: rgba(255, 255, 255, .92);
}

.ef * { box-sizing: border-box; }

/* ── Typography ── */
.ef h1, .ef h2, .ef h3 {
  font-family: var(--ef-font-display);
  letter-spacing: -.02em;
  line-height: 1.15;
  margin: 0;
}

/* ── Views ── */
.ef-view[hidden] { display: none; }

/* ── Buttons ── */
.ef-btn {
  border: 0;
  border-radius: 999px;
  padding: 11px 22px;
  font: inherit;
  font-weight: 700;
  font-size: .92rem;
  cursor: pointer;
  background: linear-gradient(135deg, var(--ef-acc), var(--ef-acc2));
  color: #fff;
  box-shadow: 0 4px 16px rgba(139, 107, 255, .22);
  transition: transform .15s, box-shadow .15s, opacity .15s;
}
.ef-btn:hover:not(:disabled) {
  transform: translateY(-1px);
  box-shadow: 0 6px 20px rgba(139, 107, 255, .35);
}
.ef-btn--ghost {
  background: transparent;
  color: var(--ef-ink);
  border: 1px solid var(--ef-line);
  box-shadow: none;
}
.ef-btn--ghost:hover:not(:disabled) {
  border-color: var(--ef-acc);
  background: rgba(139, 107, 255, .06);
  box-shadow: none;
  transform: none;
}
.ef-btn--sm { padding: 7px 14px; font-size: .82rem; }
.ef-btn:disabled { opacity: .4; cursor: not-allowed; transform: none; box-shadow: none; }
.ef-btn:focus-visible,
.ef-select:focus-visible,
.ef-input:focus-visible,
.ef-fn-input:focus-visible,
.ef-chip:focus-visible,
.ef-mc-opt:focus-visible,
.ef-tab:focus-visible,
.ef-example-btn:focus-visible {
  outline: 3px solid var(--ef-acc2);
  outline-offset: 2px;
}

/* ═══════ WELCOME ═══════ */

.ef-hero {
  text-align: center;
  margin: 0 0 36px;
  padding: 24px 16px 0;
}
.ef-eyebrow {
  margin: 0 0 10px;
  font-size: .72rem;
  font-weight: 800;
  letter-spacing: .14em;
  text-transform: uppercase;
  color: var(--ef-acc2);
}
.ef-hero-title {
  font-size: clamp(2.2rem, 5vw, 3.4rem);
  background: linear-gradient(135deg, var(--ef-acc) 10%, var(--ef-acc2) 90%);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  margin: 0 0 12px;
}
.ef-hero-desc {
  max-width: 56ch;
  margin: 0 auto;
  color: var(--ef-muted);
  font-size: 1.05rem;
  line-height: 1.6;
}

/* Mode cards */
.ef-modes {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 20px;
  margin: 0 0 28px;
}

.ef-mode-card {
  display: flex;
  flex-direction: column;
  border: 1px solid var(--ef-line);
  border-radius: 20px;
  background: var(--ef-card);
  backdrop-filter: blur(12px);
  overflow: hidden;
  cursor: pointer;
  transition: border-color .2s, box-shadow .2s, transform .2s;
}
.ef-mode-card:hover, .ef-mode-card:focus-visible {
  border-color: var(--ef-acc);
  box-shadow: 0 8px 32px rgba(139, 107, 255, .18);
  transform: translateY(-3px);
}
.ef-mode-card:focus-visible { outline: none; }

.ef-mode-preview {
  padding: 20px 20px 8px;
  display: flex;
  align-items: center;
  justify-content: center;
}
.ef-mode-svg {
  width: 100%;
  max-width: 200px;
  height: auto;
}

.ef-mode-body {
  padding: 4px 22px 24px;
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: 8px;
}
.ef-mode-body h2 {
  font-size: 1.25rem;
  margin: 0;
}
.ef-mode-body p {
  margin: 0;
  color: var(--ef-muted);
  font-size: .92rem;
  line-height: 1.55;
  flex: 1;
}
.ef-mode-cta {
  font-size: .88rem;
  font-weight: 700;
  color: var(--ef-acc2);
  transition: color .15s;
}
.ef-mode-card:hover .ef-mode-cta { color: var(--ef-acc); }
.ef-mode-card--explore:hover { border-color: var(--ef-acc); }
.ef-mode-card--learn:hover { border-color: var(--ef-acc2); }

/* Scope */
.ef-scope-wrap { margin: 0 0 20px; }
.ef-scope-toggle {
  display: flex; gap: 8px; align-items: center;
  padding: 6px 8px 6px 0; font-size: .82rem; font-weight: 700;
  color: var(--ef-muted); cursor: pointer; list-style: none;
  -webkit-user-select: none; user-select: none;
}
.ef-scope-toggle::-webkit-details-marker, .ef-scope-toggle::marker { display: none; }
.ef-scope-toggle:hover { color: var(--ef-ink); }
.ef-arr { display: inline-block; font-size: .75rem; transition: transform .15s; }
details.ef-scope-wrap[open] .ef-arr { transform: rotate(90deg); }
.ef-scope {
  border: 1px solid var(--ef-line); border-radius: var(--ef-radius);
  padding: 14px 16px; background: var(--ef-card2);
  font-size: .88rem; color: var(--ef-muted); line-height: 1.6; margin-top: 6px;
}
.ef-scope p { margin: 0 0 6px; }
.ef-scope p:last-child { margin-bottom: 0; }
.ef-scope strong { color: var(--ef-ink); }

/* ═══════ TOP BAR (shared) ═══════ */

.ef-topbar {
  display: flex;
  align-items: center;
  gap: 14px;
  margin: 0 0 20px;
  padding: 0 0 14px;
  border-bottom: 1px solid var(--ef-line);
}
.ef-topbar-title {
  font-size: 1.15rem;
  font-weight: 700;
}

/* ═══════ MODE A: EXPLORE ═══════ */

/* Function input */
.ef-input-bar {
  display: flex;
  align-items: center;
  gap: 10px;
  margin: 0 0 12px;
  padding: 10px 14px;
  border: 1px solid var(--ef-line);
  border-radius: var(--ef-radius);
  background: var(--ef-card);
  backdrop-filter: blur(8px);
}
.ef-input-label {
  font-family: var(--ef-font-mono);
  font-size: 1rem;
  font-weight: 600;
  color: var(--ef-acc2);
  white-space: nowrap;
}
.ef-fn-input {
  flex: 1;
  border: none;
  background: transparent;
  color: var(--ef-ink);
  font-family: var(--ef-font-mono);
  font-size: 1.05rem;
  padding: 6px 4px;
  outline: none;
  min-width: 0;
}
.ef-fn-input::placeholder { color: var(--ef-muted); opacity: .6; }

/* Example buttons */
.ef-fn-examples {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 6px;
  margin: 0 0 14px;
}
.ef-fn-examples-label {
  font-size: .78rem;
  font-weight: 700;
  color: var(--ef-muted);
  margin-right: 2px;
}
.ef-example-btn {
  font-family: var(--ef-font-mono);
  font-size: .78rem;
  padding: 4px 10px;
  border: 1px solid var(--ef-line);
  border-radius: 999px;
  background: var(--ef-card2);
  color: var(--ef-muted);
  cursor: pointer;
  transition: border-color .15s, color .15s;
}
.ef-example-btn:hover {
  border-color: var(--ef-acc);
  color: var(--ef-ink);
}

/* Error */
.ef-fn-error {
  padding: 10px 14px;
  margin: 0 0 14px;
  border: 1px solid var(--ef-bad);
  border-radius: 10px;
  background: rgba(251, 113, 133, .08);
  font-size: .88rem;
  color: var(--ef-bad);
}
.ef-fn-error[hidden] { display: none; }

/* Explore layout: graph + analysis */
.ef-explore-layout {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
  align-items: start;
}
.ef-explore-layout[hidden] { display: none; }

/* Graph panel */
.ef-graph-panel {
  position: sticky;
  top: 80px;
}
.ef-canvas-wrap {
  border: 1px solid var(--ef-line);
  border-radius: 16px;
  overflow: hidden;
  background: var(--ef-paper);
  touch-action: none;
}
.ef-canvas-wrap canvas {
  display: block;
  width: 100%;
  height: auto;
  cursor: grab;
  touch-action: none;
}
.ef-canvas-wrap canvas:active { cursor: grabbing; }

.ef-graph-tools {
  display: flex;
  gap: 6px;
  margin: 8px 0 6px;
}
.ef-graph-layers {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin: 0 0 6px;
}
.ef-layer-toggle {
  display: flex;
  align-items: center;
  gap: 4px;
  font-size: .76rem;
  color: var(--ef-muted);
  cursor: pointer;
}
.ef-layer-toggle input { accent-color: var(--ef-acc); }
.ef-graph-hint {
  font-size: .72rem;
  color: var(--ef-muted);
  margin: 4px 0 0;
  opacity: .7;
}
.ef-graph-coords {
  font-family: var(--ef-font-mono);
  font-size: .78rem;
  color: var(--ef-acc2);
  margin: 4px 0;
}
.ef-graph-coords[hidden] { display: none; }

/* Analysis panel */
.ef-analysis-panel {
  max-height: calc(100vh - 120px);
  overflow-y: auto;
  scrollbar-width: thin;
  scrollbar-color: var(--ef-line) transparent;
  padding-right: 4px;
}
.ef-analysis-fn {
  font-family: var(--ef-font-mono);
  font-size: 1.1rem;
  text-align: center;
  padding: 12px;
  margin: 0 0 16px;
  background: var(--ef-card);
  border: 1px solid var(--ef-line);
  border-radius: var(--ef-radius);
}

/* Analysis sections */
.ef-a-section {
  border: 1px solid var(--ef-line);
  border-radius: var(--ef-radius);
  margin: 0 0 12px;
  overflow: hidden;
  background: var(--ef-card);
}
.ef-a-header {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 12px 16px;
  cursor: pointer;
  -webkit-user-select: none;
  user-select: none;
  transition: background .15s;
}
.ef-a-header:hover { background: var(--ef-card2); }
.ef-a-number {
  width: 26px; height: 26px;
  display: flex; align-items: center; justify-content: center;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--ef-acc), var(--ef-acc2));
  color: #fff;
  font-size: .72rem;
  font-weight: 800;
  flex-shrink: 0;
}
.ef-a-title {
  font-size: .88rem;
  font-weight: 700;
  flex: 1;
}
.ef-a-result {
  font-family: var(--ef-font-mono);
  font-size: .82rem;
  color: var(--ef-acc2);
  max-width: 45%;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}
.ef-a-arrow {
  font-size: .7rem;
  color: var(--ef-muted);
  transition: transform .15s;
}
.ef-a-section.is-open .ef-a-arrow { transform: rotate(90deg); }

.ef-a-body {
  display: none;
  padding: 0 16px 14px;
}
.ef-a-section.is-open .ef-a-body { display: block; }

.ef-a-step {
  font-size: .88rem;
  line-height: 1.6;
  color: var(--ef-ink);
  padding: 4px 0;
  border-bottom: 1px solid var(--ef-line);
}
.ef-a-step:last-child { border-bottom: none; }
.ef-a-step .katex { font-size: .95em; }
.ef-a-empty {
  font-size: .84rem;
  color: var(--ef-muted);
  font-style: italic;
}

/* ═══════ MODE B: LEARN ═══════ */

.ef-learn-intro {
  color: var(--ef-muted);
  font-size: .94rem;
  line-height: 1.55;
  margin: 0 0 16px;
}

/* Progress bar */
.ef-learn-progress-bar {
  height: 6px;
  border-radius: 3px;
  background: var(--ef-card2);
  margin: 0 0 20px;
  overflow: hidden;
}
.ef-learn-progress-fill {
  height: 100%;
  border-radius: 3px;
  background: linear-gradient(90deg, var(--ef-acc), var(--ef-acc2));
  transition: width .3s;
}

/* Module cards */
.ef-modules {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 14px;
}
.ef-module-card {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 16px;
  border: 1px solid var(--ef-line);
  border-radius: var(--ef-radius);
  background: var(--ef-card);
  cursor: pointer;
  transition: border-color .15s, box-shadow .15s;
}
.ef-module-card:hover {
  border-color: var(--ef-acc);
  box-shadow: 0 4px 16px rgba(139, 107, 255, .12);
}
.ef-module-num {
  width: 36px; height: 36px;
  display: flex; align-items: center; justify-content: center;
  border-radius: 50%;
  border: 2px solid var(--ef-line);
  font-size: .82rem;
  font-weight: 800;
  color: var(--ef-muted);
  flex-shrink: 0;
  transition: border-color .15s, color .15s, background .15s;
}
.ef-module-card.is-started .ef-module-num {
  border-color: var(--ef-acc);
  color: var(--ef-acc);
}
.ef-module-card.is-mastered .ef-module-num {
  border-color: var(--ef-ok);
  background: var(--ef-ok);
  color: #fff;
}
.ef-module-info { flex: 1; min-width: 0; }
.ef-module-name {
  font-size: .92rem;
  font-weight: 700;
  margin: 0 0 3px;
}
.ef-module-desc {
  font-size: .78rem;
  color: var(--ef-muted);
  margin: 0;
  line-height: 1.4;
}
.ef-module-stat {
  font-size: .72rem;
  color: var(--ef-acc2);
  font-weight: 700;
}

/* Module tabs */
.ef-module-title {
  font-size: 1.2rem;
  margin: 0 0 14px;
}
.ef-module-tabs {
  display: flex;
  gap: 2px;
  margin: 0 0 18px;
  border-bottom: 2px solid var(--ef-line);
}
.ef-tab {
  padding: 10px 18px;
  font: inherit;
  font-size: .88rem;
  font-weight: 700;
  color: var(--ef-muted);
  background: none;
  border: none;
  border-bottom: 2px solid transparent;
  margin-bottom: -2px;
  cursor: pointer;
  transition: color .15s, border-color .15s;
}
.ef-tab:hover { color: var(--ef-ink); }
.ef-tab.is-active {
  color: var(--ef-acc);
  border-bottom-color: var(--ef-acc);
}

/* Theory panel */
.ef-module-theory {
  padding: 0 0 16px;
}
.ef-theory-card {
  border: 1px solid var(--ef-line);
  border-radius: var(--ef-radius);
  background: var(--ef-card);
  padding: 20px;
  margin: 0 0 14px;
}
.ef-theory-card h4 {
  font-family: var(--ef-font-display);
  font-size: .95rem;
  margin: 0 0 10px;
  color: var(--ef-acc2);
}
.ef-theory-card p, .ef-theory-card li {
  font-size: .9rem;
  line-height: 1.65;
  color: var(--ef-ink);
  margin: 0 0 8px;
}
.ef-theory-card ul {
  margin: 0 0 8px;
  padding-left: 20px;
}
.ef-theory-card .katex { font-size: .95em; }
.ef-theory-example {
  border-left: 3px solid var(--ef-acc);
  padding: 10px 14px;
  margin: 10px 0;
  background: var(--ef-card2);
  border-radius: 0 10px 10px 0;
  font-size: .88rem;
}
.ef-theory-start {
  margin-top: 6px;
}

/* ═══════ EXERCISE UI (Mode B) ═══════ */

.ef-ex-layout {
  display: grid;
  grid-template-columns: 1.3fr 1fr;
  gap: 20px;
  align-items: start;
}
.ef-ex-head {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
  margin: 0 0 14px;
}
.ef-block-badge {
  font-size: .72rem; font-weight: 800; letter-spacing: .08em;
  text-transform: uppercase; padding: 4px 11px; border-radius: 999px;
  border: 1px solid var(--ef-acc); color: var(--ef-acc2);
}
.ef-ex-progress { font-size: .84rem; color: var(--ef-muted); }
.ef-ex-timer {
  margin-left: auto; font-family: var(--ef-font-mono);
  font-size: .95rem; font-weight: 700; color: var(--ef-warn);
  padding: 4px 10px; border-radius: 8px; border: 1px solid var(--ef-warn);
}
.ef-ex-timer.is-low { color: var(--ef-bad); border-color: var(--ef-bad); }

.ef-statement {
  background: var(--ef-card); border: 1px solid var(--ef-line);
  border-radius: 16px; padding: 18px 20px;
  font-size: 1.06rem; line-height: 1.6; margin: 0 0 16px;
}
.ef-statement .ef-fn {
  font-family: var(--ef-font-mono);
  color: var(--ef-acc2);
  font-weight: 600;
}

.ef-input-area { margin-bottom: 14px; }
.ef-mc-list { display: grid; gap: 8px; }
.ef-mc-opt {
  display: block; width: 100%; text-align: left;
  padding: 12px 16px; border: 1px solid var(--ef-line);
  border-radius: 12px; background: var(--ef-card2);
  color: var(--ef-ink); font: inherit; font-size: .92rem;
  cursor: pointer; transition: border-color .15s, background .15s;
}
.ef-mc-opt:hover { border-color: var(--ef-acc); }
.ef-mc-opt[aria-pressed="true"] {
  border-color: var(--ef-acc); background: rgba(139, 107, 255, .14); font-weight: 700;
}
.ef-mc-opt.is-correct { border-color: var(--ef-ok); background: rgba(74, 222, 128, .12); }
.ef-mc-opt.is-wrong { border-color: var(--ef-bad); background: rgba(251, 113, 133, .12); }
.ef-mc-opt:disabled { cursor: default; opacity: .85; }

.ef-num-row { display: flex; flex-wrap: wrap; gap: 12px; align-items: center; }
.ef-num-row label {
  font-size: .82rem; color: var(--ef-muted);
  display: flex; flex-direction: column; gap: 5px;
}
.ef-text-input {
  border-radius: 10px; border: 1px solid var(--ef-line);
  background: var(--ef-paper); color: var(--ef-ink);
  font: inherit; font-size: 1rem; padding: 9px 13px; min-width: 160px;
}
.ef-text-input:focus { border-color: var(--ef-acc); outline: none; }
.ef-text-input.is-correct { border-color: var(--ef-ok); }
.ef-text-input.is-wrong { border-color: var(--ef-bad); }

.ef-actions { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 10px; }
.ef-feedback {
  font-size: .92rem; min-height: 1.3em; margin: 4px 0 10px; font-weight: 700;
}
.ef-feedback.is-ok { color: var(--ef-ok); }
.ef-feedback.is-bad { color: var(--ef-bad); }
.ef-feedback.is-info { color: var(--ef-muted); font-weight: 500; }

.ef-hints { display: grid; gap: 8px; margin-bottom: 10px; }
.ef-hint-box {
  border-left: 3px solid var(--ef-warn);
  background: var(--ef-card2); border-radius: 0 10px 10px 0;
  padding: 10px 14px; font-size: .86rem; color: var(--ef-ink); line-height: 1.5;
}
.ef-hint-box b { color: var(--ef-warn); }

.ef-solution-box {
  border: 1px solid var(--ef-acc); border-radius: var(--ef-radius);
  padding: 16px 18px; background: rgba(139, 107, 255, .06); margin-top: 6px;
}
.ef-solution-box[hidden] { display: none; }
.ef-solution-box h3 {
  font-size: .82rem; text-transform: uppercase;
  letter-spacing: .08em; color: var(--ef-acc2); margin: 0 0 10px;
}
.ef-solution-box ol { margin: 0; padding-left: 20px; display: grid; gap: 6px; }
.ef-solution-box li { font-size: .9rem; line-height: 1.55; color: var(--ef-ink); }

/* Side panel */
.ef-ex-side { position: sticky; top: 90px; }
.ef-score-mini {
  margin-top: 12px; padding: 12px 14px;
  border: 1px dashed var(--ef-line); border-radius: 12px;
  font-size: .82rem; color: var(--ef-muted); line-height: 1.6;
}
.ef-score-mini strong { color: var(--ef-ink); }

/* Completo choice */
.ef-completo-choice { display: flex; flex-wrap: wrap; gap: 10px; margin: 0 0 16px; }
.ef-completo-choice[hidden] { display: none; }

/* Guided sections */
.ef-sections[hidden] { display: none; }
.ef-sections-nav { display: flex; flex-wrap: wrap; gap: 6px; margin: 0 0 14px; }
.ef-section-chip {
  padding: 6px 12px; border-radius: 999px;
  border: 1px solid var(--ef-line); background: var(--ef-card2);
  color: var(--ef-muted); font-size: .76rem; font-weight: 700;
}
.ef-section-chip.is-current { border-color: var(--ef-acc); color: var(--ef-ink); background: rgba(139, 107, 255, .14); }
.ef-section-chip.is-ok { border-color: var(--ef-ok); color: var(--ef-ok); }
.ef-section-chip.is-bad { border-color: var(--ef-bad); color: var(--ef-bad); }
.ef-section-chip.is-self { border-color: var(--ef-warn); color: var(--ef-warn); }
.ef-section-statement {
  background: var(--ef-card); border: 1px solid var(--ef-line);
  border-radius: var(--ef-radius); padding: 14px 18px;
  font-size: .98rem; line-height: 1.55; margin: 0 0 14px;
}
.ef-section-statement b {
  color: var(--ef-acc2); font-size: .72rem;
  text-transform: uppercase; letter-spacing: .08em;
  display: block; margin-bottom: 6px;
}
.ef-sections-summary { margin-top: 16px; display: grid; gap: 8px; }
.ef-sections-summary[hidden] { display: none; }
.ef-sections-summary__row {
  display: flex; align-items: center; justify-content: space-between;
  gap: 10px; padding: 9px 14px; border: 1px solid var(--ef-line);
  border-radius: 10px; font-size: .86rem;
}
.ef-sections-summary__row.is-ok { border-color: var(--ef-ok); }
.ef-sections-summary__row.is-bad { border-color: var(--ef-bad); }
.ef-sections-summary__row.is-self { border-color: var(--ef-warn); }
.ef-sections-summary__tag {
  font-size: .7rem; font-weight: 800; text-transform: uppercase;
  letter-spacing: .06em; padding: 2px 9px; border-radius: 999px;
}
.ef-sections-summary__row.is-ok .ef-sections-summary__tag { background: rgba(74, 222, 128, .14); color: var(--ef-ok); }
.ef-sections-summary__row.is-bad .ef-sections-summary__tag { background: rgba(251, 113, 133, .14); color: var(--ef-bad); }
.ef-sections-summary__row.is-self .ef-sections-summary__tag { background: rgba(245, 192, 74, .14); color: var(--ef-warn); }

/* Summary */
#ef-summary[hidden] { display: none; }
#ef-summary-body { display: grid; gap: 14px; margin: 0 0 18px; }
.ef-sum-grid {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(140px, 1fr)); gap: 12px;
}
.ef-sum-tile {
  border: 1px solid var(--ef-line); border-radius: var(--ef-radius);
  padding: 14px 16px; background: var(--ef-card);
}
.ef-sum-tile strong {
  display: block; font-size: 1.5rem;
  font-family: var(--ef-font-mono); color: var(--ef-acc2);
}
.ef-sum-tile span {
  font-size: .72rem; color: var(--ef-muted);
  text-transform: uppercase; letter-spacing: .06em;
}
.ef-sum-block-row {
  display: flex; align-items: center; gap: 10px;
  font-size: .86rem; padding: 8px 0; border-bottom: 1px solid var(--ef-line);
}
.ef-sum-block-row .ef-bar {
  flex: 1; height: 7px; border-radius: 4px;
  background: var(--ef-card2); overflow: hidden;
}
.ef-sum-block-row .ef-bar > i {
  display: block; height: 100%;
  background: linear-gradient(90deg, var(--ef-acc), var(--ef-acc2));
}
.ef-sum-errors {
  border: 1px solid var(--ef-bad); border-radius: var(--ef-radius);
  padding: 14px 16px; background: rgba(251, 113, 133, .06);
}
.ef-sum-errors h3 {
  font-size: .82rem; color: var(--ef-bad); margin: 0 0 10px;
  text-transform: uppercase; letter-spacing: .06em;
}
.ef-sum-errors ul {
  margin: 0; padding-left: 18px;
  display: grid; gap: 6px; font-size: .84rem; color: var(--ef-ink);
}

/* Fields (setup) */
.ef-field { margin-bottom: 14px; }
.ef-field-label {
  display: block; font-size: .72rem; font-weight: 800;
  letter-spacing: .1em; text-transform: uppercase;
  color: var(--ef-muted); margin-bottom: 8px;
}
.ef-field-row { display: flex; flex-wrap: wrap; gap: 14px; }
.ef-field-row .ef-field { min-width: 160px; flex: 1; }
.ef-select, .ef-input {
  width: 100%; border-radius: 12px;
  border: 1px solid var(--ef-line);
  background: var(--ef-paper); color: var(--ef-ink);
  font: inherit; font-size: .95rem; padding: 10px 14px;
}
.ef-blocks { display: flex; flex-wrap: wrap; gap: 8px; }
.ef-chip {
  display: inline-flex; align-items: center; gap: 6px;
  border: 1px solid var(--ef-line); background: transparent;
  color: var(--ef-ink); border-radius: 999px; padding: 8px 15px;
  font: inherit; font-size: .84rem; cursor: pointer;
  transition: border-color .15s, background .15s;
}
.ef-chip[aria-pressed="true"] {
  border-color: var(--ef-acc); background: rgba(139, 107, 255, .14); font-weight: 700;
}

/* ═══════ RESPONSIVE ═══════ */

@media (max-width: 860px) {
  .ef-explore-layout {
    grid-template-columns: 1fr;
  }
  .ef-graph-panel {
    position: static;
    order: -1;
  }
  .ef-analysis-panel {
    max-height: none;
  }
  .ef-ex-layout {
    grid-template-columns: 1fr;
  }
  .ef-ex-side {
    position: static;
    order: -1;
  }
}

@media (max-width: 640px) {
  .ef-modes {
    grid-template-columns: 1fr;
  }
  .ef-modules {
    grid-template-columns: 1fr;
  }
  .ef-input-bar {
    flex-wrap: wrap;
  }
  .ef-fn-input {
    width: 100%;
    flex-basis: 100%;
  }
  .ef-field-row { flex-direction: column; }
  .ef-btn { padding: 10px 16px; font-size: .86rem; }
  .ef-hero-title { font-size: 2rem; }
}

@media (max-width: 480px) {
  .ef-mode-preview { padding: 12px 12px 4px; }
  .ef-mode-body { padding: 4px 14px 18px; }
  .ef-statement { padding: 14px 16px; font-size: .98rem; }
  .ef-a-result { display: none; }
}

@media (prefers-reduced-motion: reduce) {
  .ef-btn, .ef-mc-opt, .ef-chip, .ef-mode-card, .ef-a-arrow { transition: none; }
  .ef-mode-card:hover { transform: none; }
}

/* KaTeX overrides */
.ef .katex { font-size: 1em; }
.ef-a-body .katex { font-size: .95em; }

/* ═══════ INPUT ZONE & MATH KEYBOARD ═══════ */

.ef-input-zone { margin: 0 0 14px; }
.ef-input-zone .ef-input-bar { margin-bottom: 0; }

.ef-input-hint {
  font-size: .78rem;
  color: var(--ef-muted);
  margin: 6px 0 0;
  padding: 0 2px;
  line-height: 1.5;
}
.ef-input-hint code {
  font-family: var(--ef-font-mono);
  font-size: .74rem;
  background: var(--ef-card2);
  padding: 1px 5px;
  border-radius: 4px;
  border: 1px solid var(--ef-line);
  color: var(--ef-acc2);
}
.ef-hint-link {
  background: none;
  border: none;
  color: var(--ef-acc2);
  cursor: pointer;
  font: inherit;
  font-size: inherit;
  padding: 0;
  text-decoration: underline;
  text-underline-offset: 2px;
  transition: color .12s;
}
.ef-hint-link:hover { color: var(--ef-acc); }

.ef-kb-toggle {
  border-radius: 10px;
  font-size: .88rem;
  padding: 7px 11px;
  min-width: 38px;
  flex-shrink: 0;
}
.ef-kb-toggle[aria-expanded="true"] {
  background: rgba(139, 107, 255, .12);
  border-color: var(--ef-acc);
  color: var(--ef-acc);
}

.ef-mathkb {
  margin-top: 8px;
  border: 1px solid var(--ef-line);
  border-radius: var(--ef-radius);
  background: var(--ef-card);
  backdrop-filter: blur(12px);
  padding: 14px 14px 10px;
  animation: ef-kb-open .14s ease-out;
}
.ef-mathkb[hidden] { display: none; }

@keyframes ef-kb-open {
  from { opacity: 0; transform: translateY(-4px); }
  to   { opacity: 1; transform: translateY(0); }
}
@media (prefers-reduced-motion: reduce) {
  @keyframes ef-kb-open { from, to { opacity: 1; transform: none; } }
}

.ef-kb-sections {
  display: flex;
  flex-wrap: wrap;
  gap: 18px;
  align-items: flex-start;
}

.ef-kb-group {
  display: flex;
  flex-direction: column;
  gap: 0;
}

.ef-kb-glabel {
  font-size: .66rem;
  font-weight: 700;
  letter-spacing: .1em;
  text-transform: uppercase;
  color: var(--ef-muted);
  margin: 0 0 6px;
}

.ef-kb-rows { display: flex; flex-direction: column; gap: 4px; }
.ef-kb-row  { display: flex; gap: 4px; }

.ef-key {
  border: 1px solid var(--ef-line);
  border-radius: 8px;
  padding: 0;
  width: 42px;
  height: 42px;
  font-size: .9rem;
  font-weight: 600;
  cursor: pointer;
  background: var(--ef-card2);
  color: var(--ef-ink);
  transition: background .12s, border-color .12s, transform .08s;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  touch-action: manipulation;
  -webkit-tap-highlight-color: transparent;
  user-select: none;
  -webkit-user-select: none;
}
.ef-key:hover {
  border-color: var(--ef-acc);
  background: rgba(139, 107, 255, .1);
  color: var(--ef-ink);
}
.ef-key:active { transform: scale(.88); }
.ef-key:focus-visible {
  outline: 3px solid var(--ef-acc2);
  outline-offset: 2px;
}

.ef-key--op  { color: var(--ef-acc2); font-size: 1.05rem; }
.ef-key--var { color: var(--ef-acc); font-weight: 800; font-family: var(--ef-font-mono); font-size: 1.05rem; }
.ef-key--const { color: var(--ef-acc2); font-weight: 800; font-size: 1rem; }
.ef-key--pow { font-family: var(--ef-font-mono); color: var(--ef-acc); font-size: .88rem; }

.ef-key--fn {
  font-family: var(--ef-font-mono);
  font-size: .78rem;
  color: var(--ef-acc2);
  width: auto;
  padding: 0 10px;
  min-width: 48px;
  height: 42px;
}
.ef-key--fn:hover { color: var(--ef-ink); }

.ef-key--del { color: var(--ef-bad); }
.ef-key--del:hover { border-color: var(--ef-bad); background: rgba(251, 113, 133, .09); }

.ef-kb-note {
  font-size: .7rem;
  color: var(--ef-muted);
  margin: 10px 0 0;
  padding-top: 8px;
  border-top: 1px solid var(--ef-line);
  line-height: 1.5;
}
.ef-kb-note code {
  font-family: var(--ef-font-mono);
  font-size: .68rem;
  background: var(--ef-card2);
  padding: 1px 4px;
  border-radius: 3px;
  border: 1px solid var(--ef-line);
}

@media (max-width: 600px) {
  .ef-kb-sections { gap: 12px; }
  .ef-key { width: 38px; height: 38px; font-size: .84rem; }
  .ef-key--fn { min-width: 42px; padding: 0 8px; font-size: .72rem; height: 38px; }
  .ef-key--op { font-size: .95rem; }
}

/* ── MathLive math-field ── */
math-field.ef-fn-input {
  flex: 1;
  min-width: 0;
  border: none;
  background: transparent;
  color: var(--ef-ink);
  font-size: 1.1rem;
  padding: 4px 2px;
  outline: none;
  /* MathLive custom properties */
  --caret-color: var(--ef-acc, #6757f5);
  --selection-background-color: rgba(103, 87, 245, 0.28);
  --contains-highlight-background-color: rgba(103, 87, 245, 0.07);
  --smart-fence-color: var(--ef-acc2, #00d4b1);
}

/* Focus ring on the container when math-field is active */
.ef-input-bar:focus-within {
  border-color: var(--ef-acc2, #00d4b1);
}

/* Fallback: keep native input styled in case math-field fails to load */
input.ef-fn-input {
  flex: 1;
  border: none;
  background: transparent;
  color: var(--ef-ink);
  font-family: var(--ef-font-mono);
  font-size: 1.05rem;
  padding: 6px 4px;
  outline: none;
  min-width: 0;
}

@media (max-width: 640px) {
  math-field.ef-fn-input {
    width: 100%;
    flex-basis: 100%;
  }
}