:root {
  --bg: #07111f;
  --panel: #0d1b2a;
  --panel-2: #12263a;
  --text: #edf6ff;
  --muted: #9fb3c8;
  --accent: #38bdf8;
  --accent-2: #22c55e;
  --warning: #f59e0b;
  --danger: #ef4444;
  --border: rgba(255,255,255,.10);
  --shadow: 0 18px 45px rgba(0,0,0,.25);
  --radius: 18px;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: Inter, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  background:
    radial-gradient(circle at top left, rgba(56,189,248,.14), transparent 32%),
    radial-gradient(circle at top right, rgba(34,197,94,.09), transparent 28%),
    var(--bg);
  color: var(--text);
  line-height: 1.5;
}
a { color: inherit; }
header {
  padding: 44px 20px 30px;
  text-align: center;
  border-bottom: 1px solid var(--border);
  background: rgba(7,17,31,.72);
}
.eyebrow {
  display: inline-block;
  padding: 6px 10px;
  border: 1px solid rgba(56,189,248,.35);
  border-radius: 999px;
  color: var(--accent);
  font-size: .82rem;
  font-weight: 700;
  letter-spacing: .08em;
  text-transform: uppercase;
  margin-bottom: 14px;
}
h1 {
  margin: 0;
  font-size: clamp(2rem, 5vw, 3.4rem);
  line-height: 1.05;
}
header p {
  max-width: 820px;
  margin: 16px auto 0;
  color: var(--muted);
}
.topbar {
  position: sticky;
  top: 0;
  z-index: 10;
  background: rgba(7,17,31,.9);
  backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--border);
}
.topbar-inner {
  width: min(1180px, calc(100% - 28px));
  margin: auto;
  padding: 10px 0;
  display: flex;
  justify-content: space-between;
  gap: 10px;
}
.topbar a {
  text-decoration: none;
  color: var(--muted);
  padding: 9px 12px;
  border-radius: 10px;
}
.topbar a:hover { color: var(--text); background: rgba(255,255,255,.06); }
main {
  width: min(1180px, calc(100% - 28px));
  margin: 34px auto 60px;
}
.card-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0,1fr));
  gap: 20px;
}
.index-card, .card {
  background: linear-gradient(180deg, rgba(18,38,58,.96), rgba(13,27,42,.96));
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}
.index-card {
  padding: 24px;
  text-decoration: none;
  transition: transform .15s ease, border-color .15s ease;
}
.index-card:hover {
  transform: translateY(-3px);
  border-color: rgba(56,189,248,.55);
}
.index-card h2 { margin: 0 0 8px; }
.index-card p { color: var(--muted); margin: 0 0 20px; }
.card-header {
  padding: 22px 22px 14px;
  border-bottom: 1px solid var(--border);
}
.card-header h2 { margin: 0; }
.card-header p { margin: 8px 0 0; color: var(--muted); }
.card-body { padding: 22px; }
.section-title {
  margin: 24px 0 12px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--border);
  color: var(--accent);
  font-size: 1rem;
}
.section-title:first-child { margin-top: 0; }
.form-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0,1fr));
  gap: 14px;
}
.form-grid.three { grid-template-columns: repeat(3, minmax(0,1fr)); }
.field {
  display: flex;
  flex-direction: column;
  gap: 7px;
}
.field.full { grid-column: 1 / -1; }
label {
  font-size: .88rem;
  color: #c9d8e8;
  font-weight: 650;
}
.inline-help {
  color: var(--muted);
  font-size: .76rem;
  font-weight: 400;
}
input, select {
  width: 100%;
  border: 1px solid var(--border);
  background: rgba(6,15,27,.85);
  color: var(--text);
  border-radius: 12px;
  padding: 12px 13px;
  font-size: 1rem;
  outline: none;
}
input:focus, select:focus {
  border-color: rgba(56,189,248,.75);
  box-shadow: 0 0 0 3px rgba(56,189,248,.12);
}
.actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 18px;
}
button, .button-link {
  border: 0;
  border-radius: 12px;
  padding: 11px 16px;
  font-size: .92rem;
  font-weight: 750;
  cursor: pointer;
  text-decoration: none;
}
.primary {
  background: linear-gradient(135deg, var(--accent), #0ea5e9);
  color: #03121e;
}
.secondary {
  background: rgba(255,255,255,.07);
  color: var(--text);
  border: 1px solid var(--border);
}
.result {
  margin-top: 20px;
  padding: 18px;
  border-radius: 14px;
  background: rgba(3,12,22,.74);
  border: 1px solid rgba(56,189,248,.22);
}
.result h3 {
  margin: 0 0 12px;
  color: var(--accent);
  font-size: 1rem;
}
.result-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0,1fr));
  gap: 10px;
}
.metric {
  padding: 12px;
  background: rgba(255,255,255,.035);
  border: 1px solid var(--border);
  border-radius: 11px;
}
.metric span {
  display: block;
  color: var(--muted);
  font-size: .8rem;
  margin-bottom: 4px;
}
.metric strong { font-size: 1.06rem; }
.note, .warning {
  margin-top: 18px;
  padding: 15px;
  border-radius: 12px;
}
.note {
  color: var(--muted);
  background: rgba(56,189,248,.05);
  border: 1px solid rgba(56,189,248,.18);
}
.warning {
  color: #f8deb0;
  background: rgba(245,158,11,.08);
  border: 1px solid rgba(245,158,11,.28);
}
.complex-box {
  font-family: "Courier New", monospace;
  font-size: 1.05rem;
}
.transmission-layout {
  display: grid;
  grid-template-columns: minmax(0,1.15fr) minmax(320px,.85fr);
  gap: 20px;
  align-items: start;
}
.visual-panel {
  padding: 18px;
  border-radius: 14px;
  border: 1px solid var(--border);
  background: rgba(3,12,22,.55);
}
.visual-panel h3 { margin: 0 0 12px; color: var(--accent); font-size: 1rem; }
.line-diagram {
  width: 100%;
  min-height: 250px;
  display: block;
  border-radius: 12px;
  border: 1px solid rgba(255,255,255,.07);
  background: rgba(4,13,24,.75);
}
footer {
  text-align: center;
  color: var(--muted);
  padding: 28px 18px 44px;
  font-size: .86rem;
}
@media (max-width: 900px) {
  .transmission-layout { grid-template-columns: 1fr; }
  .form-grid.three { grid-template-columns: 1fr 1fr; }
}
@media (max-width: 700px) {
  .card-grid, .form-grid, .form-grid.three, .result-grid { grid-template-columns: 1fr; }
}

/* Línea de transmisión v0.2 */
.impedance-location {
  margin: 0;
  padding: 10px 13px;
  border: 1px solid var(--border);
  border-radius: 12px;
  background: rgba(6,15,27,.55);
}
.impedance-location legend {
  padding: 0 5px;
  color: #c9d8e8;
  font-size: .88rem;
  font-weight: 650;
}
.impedance-location label {
  display: flex;
  align-items: center;
  gap: 8px;
  margin: 4px 0;
  font-weight: 500;
}
.impedance-location input { width: auto; }
.transmission-result { padding: 18px; }
.classic-results-layout {
  display: grid;
  grid-template-columns: minmax(0, 1.15fr) minmax(340px, .85fr);
  gap: 18px;
  align-items: stretch;
}
.impedance-results,
.loss-results {
  border: 1px solid var(--border);
  border-radius: 12px;
  background: rgba(255,255,255,.025);
  padding: 14px;
}
.result-table-row {
  display: grid;
  grid-template-columns: minmax(110px, 1fr) minmax(105px, .9fr) minmax(105px, .9fr);
  gap: 8px;
  align-items: center;
  padding: 8px 4px;
  border-bottom: 1px solid rgba(255,255,255,.07);
}
.result-table-row:last-child { border-bottom: 0; }
.result-table-row span { color: var(--muted); font-size: .86rem; }
.result-table-row strong {
  padding: 7px 8px;
  border: 1px solid var(--border);
  border-radius: 7px;
  background: rgba(3,12,22,.74);
  text-align: right;
  font-family: "Courier New", monospace;
  font-size: .92rem;
}
.result-table-head strong {
  border: 0;
  background: transparent;
  text-align: center;
  color: var(--accent);
  font-family: inherit;
}
.line-summary-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 9px;
  margin-top: 14px;
}
.line-summary-grid div {
  padding: 10px;
  border: 1px solid var(--border);
  border-radius: 9px;
  background: rgba(3,12,22,.52);
}
.line-summary-grid span { display: block; color: var(--muted); font-size: .76rem; }
.line-summary-grid strong { display: block; margin-top: 3px; font-size: .92rem; }
.loss-results {
  display: grid;
  grid-template-columns: minmax(220px, 1fr) 150px;
  gap: 14px;
}
.loss-row {
  display: grid;
  grid-template-columns: minmax(120px, 1fr) 72px 82px;
  gap: 7px;
  align-items: center;
  padding: 8px 0;
  border-bottom: 1px solid rgba(255,255,255,.07);
}
.loss-row span { color: var(--muted); font-size: .84rem; }
.loss-row strong { text-align: right; font-family: "Courier New", monospace; font-size: .88rem; }
.loss-head span, .loss-head strong { color: var(--accent); font-family: inherit; }
.load-power-row {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  margin-top: 12px;
  padding: 10px;
  border-radius: 9px;
  background: rgba(34,197,94,.08);
  border: 1px solid rgba(34,197,94,.25);
}
.load-power-row span { color: #cfead8; }
.loss-bars {
  display: flex;
  justify-content: space-around;
  align-items: flex-end;
  gap: 9px;
  min-height: 230px;
  padding-top: 6px;
}
.loss-bar-wrap { width: 38px; text-align: center; }
.loss-percent { height: 22px; font-size: .72rem; color: var(--muted); }
.loss-bar {
  position: relative;
  height: 165px;
  width: 16px;
  margin: 0 auto 7px;
  overflow: hidden;
  border: 1px solid rgba(255,255,255,.22);
  background: rgba(255,255,255,.04);
}
.loss-bar span { position: absolute; left: 3px; right: 3px; bottom: 3px; min-height: 0; }
.bar-conductor { background: #ef4444; }
.bar-dielectric { background: #22c55e; }
.bar-reflection { background: #2563eb; }
.loss-bar-label { font-size: .68rem; color: var(--muted); }
@media (max-width: 980px) {
  .classic-results-layout { grid-template-columns: 1fr; }
}
@media (max-width: 620px) {
  .loss-results { grid-template-columns: 1fr; }
  .loss-bars { min-height: 190px; }
  .loss-bar { height: 125px; }
  .result-table-row { grid-template-columns: 90px 1fr 1fr; }
  .line-summary-grid { grid-template-columns: 1fr; }
}

.checkbox-field {
  flex-direction: row;
  align-items: center;
  justify-content: space-between;
  padding: 12px 13px;
  border: 1px solid var(--border);
  border-radius: 12px;
  background: rgba(6,15,27,.55);
  color: #c9d8e8;
  font-weight: 650;
}
.checkbox-field input {
  width: auto;
  transform: scale(1.15);
}
.plot-card {
  margin-top: 20px;
  border: 1px solid var(--border);
  border-radius: 12px;
  background: rgba(255,255,255,.025);
  overflow: hidden;
}
.plot-header {
  padding: 14px 14px 10px;
  border-bottom: 1px solid rgba(255,255,255,.07);
}
.plot-header h4 {
  margin: 0;
  color: var(--accent);
  font-size: 1rem;
}
.plot-header p {
  margin: 6px 0 0;
  color: var(--muted);
  font-size: .85rem;
}
.frequency-plot {
  display: block;
  width: 100%;
  height: auto;
}
.plot-bg { fill: rgba(3,12,22,.72); }
.plot-grid, .plot-grid-vertical {
  stroke: rgba(255,255,255,.08);
  stroke-width: 1;
}
.plot-axis {
  stroke: rgba(255,255,255,.32);
  stroke-width: 1.2;
}
.axis-secondary { stroke: rgba(56,189,248,.25); }
.plot-axis-label, .plot-axis-title, .plot-title-left, .plot-title-right {
  fill: #9fb3c8;
  font-size: 13px;
  font-family: Inter, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}
.plot-title-left, .plot-title-right {
  font-weight: 700;
}
.plot-axis-left { text-anchor: end; }
.plot-line {
  fill: none;
  stroke-width: 2.5;
  stroke-linecap: round;
  stroke-linejoin: round;
}
.line-r { stroke: #f59e0b; }
.line-x { stroke: #22c55e; }
.line-swr { stroke: #38bdf8; }
.plot-legend {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
  padding: 12px 14px 16px;
  color: var(--muted);
  font-size: .86rem;
}
.legend-item {
  display: inline-flex;
  align-items: center;
  gap: 8px;
}
.legend-swatch {
  display: inline-block;
  width: 18px;
  height: 3px;
  border-radius: 999px;
}
.legend-r { background: #f59e0b; }
.legend-x { background: #22c55e; }
.legend-swr { background: #38bdf8; }

/* Línea de transmisión v0.4 */
.tl-input-row {
  display: grid;
  gap: 12px;
  align-items: end;
}
.tl-line-row { grid-template-columns: minmax(190px, 1.6fr) repeat(5, minmax(95px, .72fr)); }
.tl-frequency-row { grid-template-columns: minmax(130px, .75fr) minmax(130px, .75fr) minmax(130px, .75fr) minmax(190px, 1fr); }
.tl-length-row { grid-template-columns: minmax(140px, .75fr) minmax(170px, .9fr) minmax(150px, .75fr); max-width: 650px; }
.dual-plots {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 18px;
  margin-top: 20px;
}
.dual-plots .plot-card { margin-top: 0; }
@media (max-width: 1050px) {
  .tl-line-row { grid-template-columns: repeat(3, minmax(0, 1fr)); }
}
@media (max-width: 820px) {
  .tl-frequency-row, .tl-length-row, .dual-plots { grid-template-columns: 1fr; max-width: none; }
}
@media (max-width: 620px) {
  .tl-line-row { grid-template-columns: 1fr; }
}


/* Advertencia de ROE extrema */
.swr-warning {
  margin-top: 18px;
  padding: 13px 15px;
  border: 1px solid rgba(245, 158, 11, .55);
  border-radius: 10px;
  background: rgba(245, 158, 11, .12);
  color: #fde7bd;
  font-size: .9rem;
}
.swr-warning strong { color: #fbbf24; }

/* Conversor de la Ley de Ohm */
.ohm-table {
  border: 1px solid var(--border);
  border-radius: 12px;
  overflow: hidden;
}
.ohm-row {
  display: grid;
  grid-template-columns: 130px 150px minmax(0, 1fr);
  align-items: stretch;
  border-bottom: 1px solid var(--border);
}
.ohm-row:last-child { border-bottom: 0; }
.ohm-row > label {
  display: flex;
  align-items: center;
  padding: 12px 14px;
  background: rgba(255,255,255,.025);
  border-right: 1px solid var(--border);
}
.ohm-row > input {
  margin: 7px;
  width: calc(100% - 14px);
}
.ohm-units {
  display: grid;
  grid-template-columns: repeat(4, minmax(125px, 1fr));
}
.ohm-units label {
  display: flex;
  align-items: center;
  gap: 7px;
  padding: 10px 12px;
  border-left: 1px solid var(--border);
  background: rgba(56,189,248,.045);
  font-weight: 500;
}
.ohm-units input {
  width: auto;
  margin: 0;
  padding: 0;
}
.ohm-actions {
  justify-content: center;
}
.ohm-message:empty {
  display: none;
}
@media (max-width: 900px) {
  .ohm-row {
    grid-template-columns: 110px minmax(130px, .6fr) minmax(0, 1.4fr);
  }
  .ohm-units {
    grid-template-columns: repeat(2, minmax(130px, 1fr));
  }
}
@media (max-width: 620px) {
  .ohm-row {
    grid-template-columns: 1fr;
  }
  .ohm-row > label {
    border-right: 0;
    border-bottom: 1px solid var(--border);
  }
  .ohm-units {
    grid-template-columns: 1fr 1fr;
  }
  .ohm-units label {
    border-top: 1px solid var(--border);
  }
}