/* =========================================================
   ElectroLab · Principios de Electrónica & Electrónica Analógica
   Paleta: azul acero / grafito / ámbar (acento), cielo estrellado
   ========================================================= */

:root{
  --bg-0:#05070d;
  --bg-1:#0a0f1e;
  --bg-2:#0d1526;
  --panel:#101a30cc;
  --panel-solid:#101a30;
  --border:#233355;
  --border-soft:#1a2740;

  --text-hi:#e8ecf5;
  --text-mid:#a9b6cf;
  --text-low:#6b7a99;

  --blue:#3b82f6;
  --blue-soft:#60a5fa;
  --blue-deep:#1e40af;
  --cyan:#22d3ee;
  --amber:#f59e0b;
  --amber-soft:#fbbf24;
  --green:#22c55e;
  --red:#ef4444;

  --radius-lg:18px;
  --radius-md:12px;
  --radius-sm:8px;

  --shadow-lg:0 20px 60px -20px rgba(0,0,0,.7);
  --shadow-md:0 10px 30px -12px rgba(0,0,0,.6);

  --mono: "JetBrains Mono", "Fira Code", ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  --sans: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

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

html,body{
  height:100%;
}

body{
  margin:0;
  font-family:var(--sans);
  color:var(--text-hi);
  background:var(--bg-0);
  min-height:100vh;
  overflow-x:hidden;
  line-height:1.55;
}

#estrellas{
  position:fixed;
  inset:0;
  z-index:0;
  background:
    radial-gradient(ellipse 120% 80% at 20% -10%, #10203f 0%, transparent 55%),
    radial-gradient(ellipse 100% 60% at 90% 0%, #0e1a35 0%, transparent 50%),
    linear-gradient(180deg, var(--bg-0) 0%, var(--bg-1) 45%, var(--bg-2) 100%);
}

.contenido-app{
  position:relative;
  z-index:1;
  max-width:1180px;
  margin:0 auto;
  padding:28px 20px 80px;
}

/* ---------- Header ---------- */
.app-header{
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap:16px;
  flex-wrap:wrap;
  margin-bottom:28px;
}

.brand{
  display:flex;
  align-items:center;
  gap:14px;
}

.brand-icono{
  width:46px;height:46px;
  border-radius:12px;
  display:flex;align-items:center;justify-content:center;
  background:linear-gradient(145deg, var(--blue-deep), #0b1230);
  border:1px solid var(--border);
  box-shadow:0 0 0 1px rgba(59,130,246,.12), var(--shadow-md);
  font-size:22px;
}

.brand h1{
  font-size:1.15rem;
  margin:0;
  letter-spacing:.2px;
  color:var(--text-hi);
}
.brand p{
  margin:2px 0 0;
  font-size:.8rem;
  color:var(--text-low);
  font-family:var(--mono);
}

.header-pill{
  font-family:var(--mono);
  font-size:.72rem;
  color:var(--cyan);
  background:#0b1830;
  border:1px solid #16324f;
  padding:6px 12px;
  border-radius:999px;
  display:flex;
  align-items:center;
  gap:8px;
}
.header-pill .dot{
  width:7px;height:7px;border-radius:50%;
  background:var(--green);
  box-shadow:0 0 8px var(--green);
  animation:parpadeo 2.4s ease-in-out infinite;
}
@keyframes parpadeo{ 0%,100%{opacity:1} 50%{opacity:.25} }

/* ---------- Ventana central ---------- */
.ventana{
  background:var(--panel);
  border:1px solid var(--border);
  border-radius:var(--radius-lg);
  box-shadow:var(--shadow-lg);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  overflow:hidden;
}

.ventana-barra{
  display:flex;
  align-items:center;
  gap:8px;
  padding:12px 16px;
  background:linear-gradient(180deg,#0f1830,#0b1226);
  border-bottom:1px solid var(--border-soft);
}
.ventana-barra .luz{ width:11px;height:11px;border-radius:50%; }
.luz.roja{background:#ff5f57}
.luz.amarilla{background:#febc2e}
.luz.verde{background:#28c840}
.ventana-barra .titulo-barra{
  margin-left:10px;
  font-family:var(--mono);
  font-size:.75rem;
  color:var(--text-low);
}

/* ---------- Tabs principales ---------- */
.tabs-principales{
  display:flex;
  gap:4px;
  padding:10px 12px 0;
  overflow-x:auto;
  scrollbar-width:thin;
}
.tab-btn{
  flex:0 0 auto;
  display:flex;
  align-items:center;
  gap:8px;
  background:transparent;
  border:1px solid transparent;
  color:var(--text-mid);
  font-family:var(--sans);
  font-size:.86rem;
  font-weight:600;
  padding:11px 18px;
  border-radius:10px 10px 0 0;
  cursor:pointer;
  white-space:nowrap;
  transition:all .18s ease;
}
.tab-btn .num{
  font-family:var(--mono);
  font-size:.72rem;
  color:var(--blue-soft);
  background:#0e1b34;
  border:1px solid var(--border);
  width:20px;height:20px;
  display:flex;align-items:center;justify-content:center;
  border-radius:6px;
}
.tab-btn:hover{ color:var(--text-hi); background:#0e1830; }
.tab-btn.activo{
  color:var(--text-hi);
  background:var(--bg-2);
  border-color:var(--border-soft);
  border-bottom-color:var(--bg-2);
}
.tab-btn.activo .num{ background:var(--blue-deep); color:#fff; border-color:var(--blue); }
.tab-btn.tab-historial.activo{ }
.tab-btn.tab-historial .num{ background:#3a2410; color:var(--amber-soft); border-color:#5a3a12; }

.tabs-linea{
  height:1px;
  background:var(--border-soft);
  margin-top:-1px;
}

/* ---------- Paneles ---------- */
.panel-problema{
  display:none;
  padding:26px 26px 30px;
  background:var(--bg-2);
  animation:fadeIn .25s ease;
}
.panel-problema.activo{ display:block; }

@keyframes fadeIn{ from{opacity:0; transform:translateY(6px)} to{opacity:1; transform:none} }

.problema-encabezado{
  display:flex;
  justify-content:space-between;
  align-items:flex-start;
  gap:20px;
  flex-wrap:wrap;
  margin-bottom:18px;
}
.problema-encabezado h2{
  margin:0 0 6px;
  font-size:1.3rem;
  color:var(--text-hi);
}
.tema-chip{
  display:inline-block;
  font-family:var(--mono);
  font-size:.7rem;
  color:var(--amber-soft);
  border:1px solid #4a3413;
  background:#221a09;
  padding:3px 10px;
  border-radius:999px;
  margin-bottom:8px;
}

/* Sub-tabs dentro de cada problema */
.subtabs{
  display:flex;
  gap:6px;
  margin:6px 0 20px;
  border-bottom:1px solid var(--border-soft);
  flex-wrap:wrap;
}
.subtab-btn{
  background:transparent;
  border:none;
  color:var(--text-low);
  font-size:.83rem;
  font-weight:600;
  padding:10px 4px;
  margin-right:22px;
  cursor:pointer;
  border-bottom:2px solid transparent;
  transition:color .15s ease, border-color .15s ease;
}
.subtab-btn:hover{ color:var(--text-mid); }
.subtab-btn.activo{ color:var(--blue-soft); border-bottom-color:var(--blue); }

.subpanel{ display:none; }
.subpanel.activo{ display:block; animation:fadeIn .2s ease; }

/* ---------- Enunciado ---------- */
.grid-enunciado{
  display:grid;
  grid-template-columns: 1.15fr 1fr;
  gap:22px;
  align-items:start;
}
@media (max-width: 860px){
  .grid-enunciado{ grid-template-columns: 1fr; }
}

.card{
  background:var(--panel-solid);
  border:1px solid var(--border-soft);
  border-radius:var(--radius-md);
  padding:18px 20px;
}
.card h3{
  margin:0 0 10px;
  font-size:.92rem;
  color:var(--blue-soft);
  text-transform:uppercase;
  letter-spacing:.06em;
}
.card p{ color:var(--text-mid); margin:0 0 10px; }
.card ul{ margin:0; padding-left:18px; color:var(--text-mid); }
.card li{ margin-bottom:6px; }

.preguntas-lista{
  list-style:none;
  margin:12px 0 0;
  padding:0;
  display:flex;
  flex-direction:column;
  gap:8px;
}
.preguntas-lista li{
  background:#0c1730;
  border:1px solid var(--border-soft);
  border-left:3px solid var(--blue);
  padding:10px 12px;
  border-radius:8px;
  font-size:.9rem;
  color:var(--text-hi);
}

.datos-tabla{
  width:100%;
  border-collapse:collapse;
  margin-top:6px;
}
.datos-tabla td{
  padding:7px 4px;
  font-family:var(--mono);
  font-size:.85rem;
  color:var(--text-mid);
  border-bottom:1px dashed var(--border-soft);
}
.datos-tabla td:first-child{ color:var(--cyan); width:34px; }

.circuito-wrap{
  background:#f4ecd8;
  border-radius:var(--radius-md);
  padding:14px;
  border:1px solid var(--border-soft);
}
.circuito-wrap img{
  width:100%;
  display:block;
  border-radius:6px;
}
.circuito-caption{
  text-align:center;
  font-size:.78rem;
  color:var(--text-low);
  margin-top:8px;
  font-family:var(--mono);
}

/* ---------- Desarrollo paso a paso ---------- */
.pasos-lista{
  display:flex;
  flex-direction:column;
  gap:12px;
}

.paso{
  background:var(--panel-solid);
  border:1px solid var(--border-soft);
  border-radius:var(--radius-md);
  overflow:hidden;
}
.paso-header{
  display:flex;
  align-items:center;
  gap:12px;
  padding:14px 16px;
  cursor:pointer;
  user-select:none;
}
.paso-header .paso-numero{
  flex:0 0 auto;
  width:30px;height:30px;
  border-radius:8px;
  background:#0e1b34;
  border:1px solid var(--border);
  color:var(--blue-soft);
  font-family:var(--mono);
  font-size:.8rem;
  display:flex;align-items:center;justify-content:center;
}
.paso.completado .paso-numero{
  background:linear-gradient(145deg, #12351f, #0c2216);
  border-color:#1f5c33;
  color:var(--green);
}
.paso-header .paso-titulo{
  flex:1;
  font-weight:600;
  font-size:.92rem;
  color:var(--text-hi);
}
.paso-header .paso-caret{
  color:var(--text-low);
  transition:transform .2s ease;
  font-size:.8rem;
}
.paso.abierto .paso-caret{ transform:rotate(90deg); color:var(--blue-soft); }
.paso.bloqueado{ opacity:.4; }
.paso.bloqueado .paso-header{ cursor:not-allowed; }

.paso-body{
  max-height:0;
  overflow:hidden;
  transition:max-height .28s ease;
  border-top:1px solid transparent;
}
.paso.abierto .paso-body{
  border-top:1px solid var(--border-soft);
}
.paso-body-inner{
  padding:16px 18px 18px 58px;
}
.paso-body-inner p{
  margin:0 0 12px;
  color:var(--text-mid);
  font-size:.92rem;
}
.paso-body-inner strong{ color:var(--text-hi); }

.formula-box{
  background:#081120;
  border:1px solid #17284a;
  border-left:3px solid var(--amber);
  border-radius:8px;
  padding:12px 16px;
  overflow-x:auto;
  color:var(--amber-soft);
  font-size:1.02rem;
}

.btn-siguiente-paso{
  margin-top:16px;
  background:var(--blue-deep);
  color:#fff;
  border:1px solid var(--blue);
  padding:9px 16px;
  border-radius:8px;
  font-size:.82rem;
  font-weight:600;
  cursor:pointer;
  transition:background .15s ease, transform .1s ease;
}
.btn-siguiente-paso:hover{ background:var(--blue); }
.btn-siguiente-paso:active{ transform:scale(.97); }
.btn-siguiente-paso:disabled{ opacity:.4; cursor:default; }

.resumen-final{
  margin-top:18px;
  background:linear-gradient(135deg,#0c2216,#0a1a10);
  border:1px solid #1f5c33;
  border-radius:var(--radius-md);
  padding:16px 18px;
  display:none;
}
.resumen-final.visible{ display:block; animation:fadeIn .3s ease; }
.resumen-final h4{
  margin:0 0 8px;
  color:var(--green);
  font-size:.85rem;
  text-transform:uppercase;
  letter-spacing:.05em;
}
.resumen-final ul{ margin:0; padding-left:18px; color:var(--text-hi); }
.resumen-final li{ margin-bottom:4px; font-size:.92rem; }

/* ---------- Práctica interactiva ---------- */
.practica-grid{
  display:grid;
  gap:14px;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  margin-bottom:18px;
}
.campo-practica label{
  display:block;
  font-size:.82rem;
  color:var(--text-mid);
  margin-bottom:6px;
}
.campo-practica input{
  width:100%;
  background:#0b1428;
  border:1px solid var(--border);
  color:var(--text-hi);
  padding:10px 12px;
  border-radius:8px;
  font-family:var(--mono);
  font-size:.95rem;
  transition:border-color .15s ease, box-shadow .15s ease;
}
.campo-practica input:focus{
  outline:none;
  border-color:var(--blue);
  box-shadow:0 0 0 3px rgba(59,130,246,.18);
}
.campo-practica input.correcto{ border-color:var(--green); box-shadow:0 0 0 3px rgba(34,197,94,.15); }
.campo-practica input.incorrecto{ border-color:var(--red); box-shadow:0 0 0 3px rgba(239,68,68,.15); }
.feedback-campo{
  font-size:.76rem;
  margin-top:5px;
  min-height:14px;
  font-family:var(--mono);
}
.feedback-campo.ok{ color:var(--green); }
.feedback-campo.fail{ color:var(--red); }

.practica-acciones{
  display:flex;
  align-items:center;
  gap:14px;
  flex-wrap:wrap;
}

.btn-primario{
  background:linear-gradient(145deg, var(--amber), #d97706);
  color:#0a0e1a;
  border:none;
  font-weight:700;
  font-size:.88rem;
  padding:11px 22px;
  border-radius:9px;
  cursor:pointer;
  box-shadow:0 8px 20px -8px rgba(245,158,11,.5);
  transition:transform .12s ease, box-shadow .12s ease;
}
.btn-primario:hover{ transform:translateY(-1px); box-shadow:0 10px 24px -8px rgba(245,158,11,.6); }
.btn-primario:active{ transform:translateY(0); }

.btn-secundario{
  background:transparent;
  color:var(--text-mid);
  border:1px solid var(--border);
  font-size:.85rem;
  padding:10px 16px;
  border-radius:9px;
  cursor:pointer;
  transition:all .15s ease;
}
.btn-secundario:hover{ color:var(--text-hi); border-color:var(--blue-soft); }

.puntaje-resultado{
  font-family:var(--mono);
  font-size:.88rem;
  color:var(--text-mid);
}
.puntaje-resultado b{ color:var(--text-hi); }

/* ---------- Historial ---------- */
.tabla-historial{
  width:100%;
  border-collapse:collapse;
  font-size:.88rem;
}
.tabla-historial th{
  text-align:left;
  color:var(--text-low);
  font-family:var(--mono);
  font-size:.72rem;
  text-transform:uppercase;
  letter-spacing:.05em;
  padding:10px 12px;
  border-bottom:1px solid var(--border-soft);
}
.tabla-historial td{
  padding:11px 12px;
  border-bottom:1px solid var(--border-soft);
  color:var(--text-mid);
}
.tabla-historial tr:hover td{ background:#0c1730; color:var(--text-hi); }

.badge-pct{
  display:inline-block;
  padding:3px 10px;
  border-radius:999px;
  font-family:var(--mono);
  font-size:.76rem;
  font-weight:700;
}
.badge-pct.alto{ background:#0c2216; color:var(--green); border:1px solid #1f5c33; }
.badge-pct.medio{ background:#241d09; color:var(--amber-soft); border:1px solid #5a4413; }
.badge-pct.bajo{ background:#2a0d0d; color:#fca5a5; border:1px solid #5c1f1f; }

.historial-vacio, .historial-cargando{
  color:var(--text-low);
  font-family:var(--mono);
  font-size:.85rem;
  padding:30px 10px;
  text-align:center;
}

.historial-header{
  display:flex;
  justify-content:space-between;
  align-items:center;
  flex-wrap:wrap;
  gap:10px;
  margin-bottom:16px;
}

/* ---------- Footer ---------- */
.app-footer{
  text-align:center;
  margin-top:26px;
  color:var(--text-low);
  font-size:.78rem;
  font-family:var(--mono);
}
.app-footer a{ color:var(--blue-soft); text-decoration:none; }

/* ---------- Responsive ---------- */
@media (max-width: 640px){
  .contenido-app{ padding:16px 12px 60px; }
  .panel-problema{ padding:18px 16px 24px; }
  .paso-body-inner{ padding:14px 14px 16px 14px; }
  .brand h1{ font-size:1rem; }
  .subtab-btn{ margin-right:14px; }
}

::selection{ background:rgba(59,130,246,.35); }

/* Scrollbar */
::-webkit-scrollbar{ width:10px; height:10px; }
::-webkit-scrollbar-track{ background:var(--bg-1); }
::-webkit-scrollbar-thumb{ background:#233355; border-radius:6px; }
::-webkit-scrollbar-thumb:hover{ background:#2c4066; }