:root {
  --bg: #0d1117;
  --bg2: #131a23;
  --panel: #161d28;
  --borde: #263041;
  --texto: #e6edf3;
  --texto2: #8b98a9;
  --verde: #4ade80;
  --verde-osc: #16a34a;
  --rojo: #ef4444;
  --ambar: #f59e0b;
  --azul: #58a6ff;
  --radio: 12px;
  --mono: ui-monospace, "Cascadia Code", "SF Mono", Menlo, Consolas, monospace;
}
* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  background: var(--bg);
  color: var(--texto);
  font-family: -apple-system, "Segoe UI", Roboto, Inter, sans-serif;
  line-height: 1.6;
  min-height: 100vh;
}
.cabecera {
  display: flex; align-items: center; justify-content: space-between; gap: 12px;
  padding: 14px clamp(16px, 4vw, 40px);
  border-bottom: 1px solid var(--borde);
  background: rgba(13,17,23,.85); backdrop-filter: blur(8px);
  position: sticky; top: 0; z-index: 10;
}
.marca { display: flex; align-items: center; gap: 10px; }
.marca__icono { width: 30px; height: 30px; border-radius: 7px; }
.marca__texto { font-size: 1rem; letter-spacing: .02em; color: var(--texto2); }
.marca__texto strong { color: var(--texto); font-weight: 700; }
.estado {
  display: inline-flex; align-items: center; gap: 8px;
  font-size: .78rem; letter-spacing: .08em; text-transform: uppercase;
  padding: 6px 14px; border-radius: 99px; border: 1px solid var(--borde);
  background: var(--bg2); transition: all .25s;
}
.estado__punto { width: 8px; height: 8px; border-radius: 50%; background: var(--texto2); transition: background .25s; }
.estado--ok { border-color: rgba(74,222,128,.35); color: var(--verde); }
.estado--ok .estado__punto { background: var(--verde); box-shadow: 0 0 8px var(--verde); }
.estado--error { border-color: rgba(239,68,68,.4); color: var(--rojo); }
.estado--error .estado__punto { background: var(--rojo); box-shadow: 0 0 8px var(--rojo); }
.estado--neutro { color: var(--texto2); }

main { max-width: 1240px; margin: 0 auto; padding: clamp(20px, 4vw, 40px) clamp(16px, 4vw, 40px); }
h1 {
  font-size: clamp(1.9rem, 5vw, 2.8rem);
  font-weight: 800; letter-spacing: -.02em; line-height: 1.15;
  margin-bottom: 22px;
  background: linear-gradient(120deg, #fff 30%, var(--verde));
  -webkit-background-clip: text; background-clip: text; -webkit-text-fill-color: transparent;
}

/* ---- Tool ---- */
.tool {
  display: grid; grid-template-columns: 1fr 1fr; gap: 16px;
  height: min(62vh, 620px); min-height: 420px;
  scroll-margin-top: 80px;
}
.panel {
  display: flex; flex-direction: column;
  background: var(--panel);
  border: 1px solid var(--borde);
  border-radius: var(--radio);
  overflow: hidden;
  box-shadow: 0 10px 40px rgba(0,0,0,.35), inset 0 1px 0 rgba(255,255,255,.04);
  animation: entrada .5s ease both;
}
.panel--resultado { animation-delay: .1s; }
@keyframes entrada { from { opacity: 0; transform: translateY(14px); } to { opacity: 1; transform: none; } }
.panel__barra {
  display: flex; align-items: center; justify-content: space-between; gap: 8px;
  padding: 8px 10px; border-bottom: 1px solid var(--borde); background: var(--bg2);
  flex-wrap: wrap;
}
.panel__titulo { font-size: .75rem; font-weight: 600; letter-spacing: .12em; text-transform: uppercase; color: var(--texto2); }
.panel__acciones { display: flex; align-items: center; gap: 6px; position: relative; }
.selector-indentacion {
  display: inline-flex; align-items: center; gap: 6px;
  font-size: .72rem; letter-spacing: .05em; color: var(--texto2);
}
select#indentacion {
  background: var(--bg); color: var(--texto2); border: 1px solid var(--borde);
  border-radius: 7px; padding: 5px 6px; font-size: .75rem; cursor: pointer;
}
.btn {
  font: inherit; font-size: .78rem; letter-spacing: .03em;
  padding: 7px 12px; min-height: 36px; border-radius: 8px; cursor: pointer;
  border: 1px solid var(--borde); background: var(--bg2); color: var(--texto);
  transition: all .18s;
}
.btn:hover { border-color: var(--azul); color: var(--azul); transform: translateY(-1px); }
.btn:focus-visible, .tab:focus-visible, .arbol__toggle:focus-visible { outline: 2px solid var(--azul); outline-offset: 2px; }
.btn--primario { background: linear-gradient(135deg, var(--verde-osc), #15803d); border-color: transparent; font-weight: 700; }
.btn--primario:hover { filter: brightness(1.15); color: #fff; }
.btn:disabled { opacity: .55; pointer-events: none; }

.editor-wrap { flex: 1; display: flex; min-height: 0; position: relative; }
.editor-gutter {
  width: 46px; padding: 12px 8px 12px 0; text-align: right;
  font: 500 .82rem/1.6 var(--mono); color: #46536a;
  background: var(--bg2); border-right: 1px solid var(--borde);
  overflow: hidden; user-select: none; flex-shrink: 0;
}
textarea#editor {
  flex: 1; width: 100%; resize: none; border: none; outline: none;
  background: transparent; color: var(--texto);
  font: 500 .86rem/1.6 var(--mono);
  padding: 12px 14px; caret-color: var(--verde);
  white-space: pre; overflow: auto;
}
textarea#editor::placeholder { color: #46536a; }

.error-linea {
  display: flex; align-items: center; gap: 10px;
  padding: 10px 14px; font-size: .84rem; color: #fca5a5;
  background: rgba(239,68,68,.09); border-top: 1px solid rgba(239,68,68,.25);
}
.error-linea[hidden] { display: none; }
.error-linea__icono { width: 18px; height: 18px; flex-shrink: 0; color: var(--rojo); }
.panel__pie {
  display: flex; gap: 8px; padding: 10px; border-top: 1px solid var(--borde);
  background: var(--bg2); flex-wrap: wrap;
}
.panel__pie .btn { flex: 1; min-width: 90px; }

.tabs { display: flex; border-bottom: 1px solid var(--borde); background: var(--bg2); }
.tab {
  flex: 1; font: 600 .78rem/1 inherit; letter-spacing: .1em; text-transform: uppercase;
  padding: 12px; background: none; border: none; color: var(--texto2);
  cursor: pointer; border-bottom: 2px solid transparent; transition: all .2s; min-height: 44px;
}
.tab.activo { color: var(--verde); border-bottom-color: var(--verde); }
.tab-vista { flex: 1; min-height: 0; overflow: auto; padding: 12px; }
.arbol__vacio { color: var(--texto2); font-size: .88rem; padding: 24px 8px; text-align: center; }
.arbol__nodo { font: .84rem/1.7 var(--mono); }
.arbol__nodo--hijo { margin-left: 18px; padding-left: 10px; border-left: 1px dashed var(--borde); }
.arbol__toggle {
  display: inline-flex; align-items: center; gap: 6px;
  background: none; border: none; color: inherit; font: inherit; cursor: pointer;
  padding: 1px 4px; border-radius: 5px; transition: background .15s;
}
.arbol__toggle:hover { background: rgba(88,166,255,.1); }
.arbol__toggle svg { transition: transform .2s; color: var(--texto2); }
.arbol__toggle.cerrado svg { transform: rotate(-90deg); }
.arbol__clave { color: var(--azul); }
.arbol__conteo { font-size: .72rem; color: var(--texto2); background: var(--bg2); border-radius: 99px; padding: 1px 8px; }
.arbol__valor--cadena { color: var(--verde); }
.arbol__valor--numero { color: var(--ambar); }
.arbol__valor--booleano { color: #c792ea; }
.arbol__valor--nulo { color: var(--texto2); font-style: italic; }
.arbol__hijos.colapsado { display: none; }

.stats { display: grid; grid-template-columns: repeat(auto-fill, minmax(130px, 1fr)); gap: 10px; }
.stats__item {
  background: var(--bg2); border: 1px solid var(--borde); border-radius: 10px;
  padding: 14px 12px; text-align: center; transition: border-color .2s;
}
.stats__item:hover { border-color: var(--verde); }
.stats__item dt { font-size: 1.45rem; font-weight: 800; color: var(--verde); }
.stats__item dd { font-size: .72rem; letter-spacing: .06em; text-transform: uppercase; color: var(--texto2); }

.menu-ejemplos {
  position: absolute; top: calc(100% + 6px); right: 0; z-index: 20;
  display: flex; flex-direction: column; min-width: 140px;
  background: var(--bg2); border: 1px solid var(--borde); border-radius: 10px;
  box-shadow: 0 12px 32px rgba(0,0,0,.5); overflow: hidden;
}
.menu-ejemplos button {
  background: none; border: none; color: var(--texto); font: inherit; font-size: .84rem;
  text-align: left; padding: 10px 14px; cursor: pointer; transition: background .15s;
}
.menu-ejemplos button:hover { background: rgba(74,222,128,.12); color: var(--verde); }

/* ---- Contenido ---- */
.contenido { max-width: 860px; margin: 48px auto 0; animation: entrada .6s ease both; }
.contenido h2 { font-size: 1.5rem; letter-spacing: -.01em; margin-bottom: 16px; }
.contenido h3 { font-size: 1.05rem; margin: 18px 0 6px; color: var(--verde); }
.contenido p { color: var(--texto2); }
.pasos { margin: 0 0 8px 20px; color: var(--texto2); }
.pasos li { margin-bottom: 10px; }
.tarjeta {
  background: var(--panel); border: 1px solid var(--borde); border-radius: var(--radio);
  padding: 22px 24px;
}
code {
  font-family: var(--mono); font-size: .84em;
  background: var(--bg2); border: 1px solid var(--borde);
  border-radius: 5px; padding: 1px 6px; color: var(--ambar);
}
details {
  background: var(--panel); border: 1px solid var(--borde); border-radius: 10px;
  margin-bottom: 10px; padding: 0; overflow: hidden;
}
summary {
  cursor: pointer; font-weight: 600; padding: 14px 18px; list-style: none;
  transition: color .2s; min-height: 44px; display: flex; align-items: center;
}
summary::before { content: "+"; margin-right: 12px; color: var(--verde); font-weight: 700; }
details[open] summary::before { content: "−"; }
summary:hover { color: var(--verde); }
details p { padding: 0 18px 16px 42px; }
.cta-suave {
  max-width: 860px; margin: 40px auto 0; text-align: center;
  padding: 26px 24px; border-radius: var(--radio);
  background: linear-gradient(135deg, rgba(74,222,128,.08), rgba(88,166,255,.06));
  border: 1px solid rgba(74,222,128,.25);
  color: var(--texto); font-size: 1.05rem;
}
.pie {
  margin-top: 56px; padding: 28px clamp(16px, 4vw, 40px);
  border-top: 1px solid var(--borde); text-align: center;
  color: var(--texto2); font-size: .85rem;
}
.pie a { color: var(--azul); text-decoration: none; }
.pie a:hover { text-decoration: underline; }
.pie p { margin-top: 8px; }

@media (max-width: 900px) {
  .tool { grid-template-columns: 1fr; height: auto; min-height: 0; }
  .panel--editor { min-height: 340px; }
  .panel--resultado { min-height: 300px; }
  .tab-vista { max-height: 320px; }
}
@media (max-width: 480px) {
  .estado span:last-child { display: none; }
  .panel__pie .btn { min-width: 70px; padding: 7px 8px; }
}