:root{
    --bg: var(--tbc-bg);
    --panel: var(--tbc-panel);
    --panel-alt: var(--tbc-panel-raised);
    --border: var(--tbc-border);
    --border-soft: var(--tbc-border-soft);
    --text: var(--tbc-ink);
    --text-muted: var(--tbc-ink-muted);
    --text-faint: var(--tbc-ink-faint);
    --amber: var(--tbc-glow);
    --amber-dim: var(--tbc-glow-dim);
    --copper: var(--tbc-glow-dim);
    --readout: var(--tbc-safe);
    --readout-dim: var(--tbc-safe);
    --danger: var(--tbc-danger);
    --radius: var(--tbc-radius);
    --font-head: var(--tbc-font-display);
    --font-body: var(--tbc-font-body);
    --font-mono: var(--tbc-font-mono);
  }
  *{box-sizing:border-box;}
  body{
    margin:0;
    background:var(--bg);
    background-image:
      radial-gradient(ellipse at top, rgba(232,137,47,0.05), transparent 55%),
      repeating-linear-gradient(0deg, rgba(255,255,255,0.012) 0px, rgba(255,255,255,0.012) 1px, transparent 1px, transparent 3px);
    color:var(--text);
    font-family:var(--font-body);
    line-height:1.5;
    -webkit-font-smoothing:antialiased;
  }
  .rt-wrap{
  font-family: var(--font-body);
  color: var(--text);
  background:
    radial-gradient(120% 140% at 15% -10%, rgba(44, 33, 23, 0.8) 0%, transparent 55%),
    linear-gradient(175deg, rgba(34, 27, 21, 0.8) 0%, rgba(28, 23, 18, 0.8) 100%);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow:
    0 1px 0 rgba(255, 255, 255, 0.04) inset,
    0 30px 60px -30px rgba(0, 0, 0, 0.6);
  max-width: 760px;
  margin: 0 auto;
  padding: 28px 28px 24px;
  box-sizing: border-box;
  position: relative;
}
  .rt-eyebrow{ font-family:var(--font-mono); font-size:11px; letter-spacing:0.16em; text-transform:uppercase; color:var(--amber); margin:0 0 6px; }
  .rt-title{ font-family:var(--font-head); font-weight:600; font-size:26px; line-height:1.15; margin:0 0 6px; color:var(--text); }
  .rt-sub{ color:var(--text-muted); font-size:13.5px; margin:0; max-width:100ch; }

  /* Tabs */
  .rt-tabs{
    display:flex;
    gap:6px;
    border-bottom:1px solid var(--border);
    margin-bottom:28px;
    flex-wrap:wrap;
  }
  .rt-tab{
    appearance:none;
    background:none;
    border:none;
    color:var(--text-muted);
    font-family:var(--font-body);
    font-weight:600;
    font-size:14.5px;
    padding:12px 4px;
    margin-right:22px;
    cursor:pointer;
    position:relative;
    border-bottom:2px solid transparent;
    transition:color 0.15s ease;
  }
  .rt-tab:hover{ color:var(--text); }
  .rt-tab.active{
    color:var(--amber);
    border-bottom-color:var(--amber);
  }

  .rt-panel{ display:none; }
  .rt-panel.active{ display:block; animation:fadein 0.25s ease; }
  @keyframes fadein{ from{opacity:0; transform:translateY(4px);} to{opacity:1; transform:none;} }

  .rt-panel-head{
    font-family:var(--font-head);
    font-size:20px;
    font-weight:700;
    margin:0 0 6px;
  }
  .rt-panel-desc{
    color:var(--text-muted);
    font-size:14.5px;
    margin:0 0 28px;
    max-width:600px;
  }

  /* Card */
  .rt-card{
    background:var(--panel);
    border:1px solid var(--border-soft);
    border-radius:var(--radius);
    padding:26px;
  }

  /* Band count selector */
  .rt-segmented{
    display:inline-flex;
    background:var(--panel-alt);
    border:1px solid var(--border);
    border-radius:8px;
    padding:3px;
    margin-bottom:26px;
  }
  .rt-segmented button{
    appearance:none;
    border:none;
    background:none;
    color:var(--text-muted);
    font-family:var(--font-mono);
    font-size:13px;
    font-weight:700;
    padding:8px 16px;
    border-radius:6px;
    cursor:pointer;
    transition:background 0.15s ease, color 0.15s ease;
  }
  .rt-segmented button.active{
    background:var(--amber);
    color:#20160a;
  }

  /* Resistor SVG */
  .rt-resistor-stage{
    background:var(--panel-alt);
    border:1px solid var(--border);
    border-radius:8px;
    padding:20px 10px;
    margin-bottom:22px;
  }
  .rt-resistor-stage svg{ width:100%; height:auto; display:block; }

  /* Band controls */
  .rt-band{
    margin-bottom:20px;
    padding-bottom:20px;
    border-bottom:1px solid var(--border-soft);
  }
  .rt-band:last-child{ border-bottom:none; margin-bottom:0; padding-bottom:0; }
  .rt-band-label{
    display:flex;
    justify-content:space-between;
    align-items:baseline;
    font-family:var(--font-mono);
    font-size:12px;
    letter-spacing:0.06em;
    text-transform:uppercase;
    color:var(--text-faint);
    margin-bottom:10px;
  }
  .rt-band-current{
    font-family:var(--font-body);
    font-weight:600;
    font-size:13.5px;
    text-transform:none;
    letter-spacing:0;
    color:var(--text);
  }
  .rt-swatches{
    display:flex;
    flex-wrap:wrap;
    gap:8px;
  }
  .rt-swatch{
    width:34px;
    height:34px;
    border-radius:7px;
    border:2px solid transparent;
    cursor:pointer;
    box-shadow: inset 0 0 0 1px rgba(0,0,0,0.35);
    transition:transform 0.1s ease, border-color 0.1s ease;
    position:relative;
  }
  .rt-swatch:hover{ transform:translateY(-2px); }
  .rt-swatch.selected{
    border-color:var(--amber);
    box-shadow: inset 0 0 0 1px rgba(0,0,0,0.35), 0 0 0 3px rgba(232,137,47,0.18);
  }
  .rt-swatch.selected::after{
    content:'';
    position:absolute;
    inset:0;
    border-radius:5px;
    box-shadow: inset 0 0 0 2px rgba(0,0,0,0.5);
  }

  /* Readout */
  .rt-readout{
    text-align:center;
    padding:22px 16px 24px;
    background:var(--panel-alt);
    border:1px solid var(--border);
    border-radius:8px;
  }
  .rt-readout-value{
    font-family:var(--font-mono);
    font-size:clamp(32px, 6vw, 44px);
    font-weight:700;
    color:var(--readout);
    text-shadow:0 0 18px rgba(127,214,138,0.25);
    letter-spacing:0.01em;
  }
  .rt-readout-row{
    display:flex;
    justify-content:center;
    gap:22px;
    margin-top:10px;
    flex-wrap:wrap;
    font-family:var(--font-mono);
    font-size:13px;
    color:var(--text-muted);
  }
  .rt-readout-row b{ color:var(--text); font-weight:600; }

  /* Two column layout for reverse/smd */
  .rt-grid-2{
    display:grid;
    grid-template-columns:1fr 1fr;
    gap:24px;
  }
  @media (max-width:720px){ .rt-grid-2{ grid-template-columns:1fr; } }

  .rt-field{ margin-bottom:18px; }
  .rt-field label{
    display:block;
    font-family:var(--font-mono);
    font-size:12px;
    letter-spacing:0.06em;
    text-transform:uppercase;
    color:var(--text-faint);
    margin-bottom:8px;
  }
  .rt-input-row{ display:flex; gap:8px; }
  .rt-input, select.rt-input{
    width:100%;
    background:var(--panel-alt);
    border:1px solid var(--border);
    color:var(--text);
    font-family:var(--font-mono);
    font-size:15px;
    padding:11px 12px;
    border-radius:7px;
    outline:none;
    transition:border-color 0.15s ease;
  }
  .rt-input:focus{ border-color:var(--amber); }
  select.rt-input{ cursor:pointer; }

  .rt-note{
    font-size:13px;
    color:var(--text-faint);
    margin-top:14px;
    line-height:1.6;
  }
  .rt-note code{
    background:var(--panel-alt);
    border:1px solid var(--border);
    padding:1px 6px;
    border-radius:4px;
    font-family:var(--font-mono);
    color:var(--copper);
    font-size:12.5px;
  }

  .rt-chip-row{
    display:flex;
    gap:8px;
    flex-wrap:wrap;
    margin-top:14px;
  }
  .rt-chip{
    display:inline-flex;
    align-items:center;
    gap:6px;
    background:var(--panel-alt);
    border:1px solid var(--border);
    padding:6px 10px;
    border-radius:20px;
    font-family:var(--font-mono);
    font-size:12.5px;
    color:var(--text-muted);
  }
  .rt-chip .dot{ width:10px; height:10px; border-radius:50%; box-shadow: inset 0 0 0 1px rgba(0,0,0,0.4); }

  .rt-warn{
    color:var(--danger);
    font-size:13.5px;
    margin-top:10px;
    display:none;
  }
  .rt-warn.show{ display:block; }

  .rt-btn{
    appearance:none;
    background:var(--panel-alt);
    border:1px solid var(--border);
    color:var(--text);
    font-family:var(--font-body);
    font-weight:600;
    font-size:13px;
    padding:9px 14px;
    border-radius:7px;
    cursor:pointer;
  }
  .rt-btn:hover{ border-color:var(--amber); color:var(--amber); }