/*
  Power Tube Bias Calculator — stylesheet
  ----------------------------------------
  Everything is namespaced under .tbc so this can be dropped into any
  existing page without clashing with other styles.

  This widget now shares its design tokens (the --tbc-* colors, fonts,
  and radii) with the rest of the site instead of declaring its own
  copy — they live once, in css/styles.css's :root block. Load that
  file before this one on any page that uses the calculator. Custom
  properties inherit normally, so re-skinning the whole site (widget
  included) just means editing styles.css; nothing in this file needs
  to change to match.
*/

.tbc {
  font-family: var(--tbc-font-body);
  color: var(--tbc-ink);
  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(--tbc-border);
  border-radius: var(--tbc-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;
}

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

.tbc :focus-visible {
  outline: 2px solid var(--tbc-glow);
  outline-offset: 2px;
}

/* ---------- header ---------- */
.tbc-header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 16px;
  margin-bottom: 18px;
}

.tbc-eyebrow {
  font-family: var(--tbc-font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--tbc-glow);
  margin: 0 0 6px;
}

.tbc-title {
  font-family: var(--tbc-font-display);
  font-size: 26px;
  font-weight: 600;
  line-height: 1.15;
  margin: 0 0 6px;
  color: var(--tbc-ink);
}

.tbc-sub {
  font-size: 13.5px;
  color: var(--tbc-ink-muted);
  margin: 0;
  max-width: 100ch;
}

.tbc-badge {
  flex: none;
  font-family: var(--tbc-font-mono);
  font-size: 10.5px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--tbc-ink-faint);
  border: 1px solid var(--tbc-border);
  border-radius: 999px;
  padding: 5px 10px;
  white-space: nowrap;
}

/* ---------- warning strip ---------- */
.tbc-warning {
  display: flex;
  gap: 10px;
  align-items: flex-start;
  background: var(--tbc-danger-soft);
  border: 1px solid rgba(224, 82, 46, 0.35);
  border-radius: var(--tbc-radius-sm);
  padding: 10px 14px;
  font-size: 12.5px;
  line-height: 1.5;
  color: #f0d3c8;
  margin-bottom: 22px;
}
.tbc-warning[hidden] { display: none; }

.tbc-warning svg { flex: none; margin-top: 2px; color: var(--tbc-danger); }
.tbc-warning strong { color: #fff; }

/* ---------- database-load notice (shown only on the EMBEDDED_TUBES_CSV fallback) ---------- */
.tbc-db-notice {
  display: flex;
  gap: 10px;
  align-items: flex-start;
  background: var(--tbc-warn-soft);
  border: 1px solid rgba(231, 184, 79, 0.35);
  border-radius: var(--tbc-radius-sm);
  padding: 10px 14px;
  font-size: 12.5px;
  line-height: 1.5;
  color: var(--tbc-ink-muted);
  margin-bottom: 22px;
}

.tbc-db-notice svg { flex: none; margin-top: 2px; color: var(--tbc-warn); }
.tbc-db-notice strong { color: var(--tbc-warn); }

/* ---------- setup row (tube + voltage) ---------- */
.tbc-setup {
  display: grid;
  grid-template-columns: 1.3fr 1fr;
  gap: 14px;
  padding: 18px;
  background: rgba(42, 33, 25, 0.8);
  border: 1px solid var(--tbc-border-soft);
  border-radius: var(--tbc-radius-sm);
}

.tbc-field {
  display: flex;
  flex-direction: column;
  gap: 6px;
  font-size: 12.5px;
  color: var(--tbc-ink-muted);
}

.tbc-field-label {
  font-family: var(--tbc-font-mono);
  font-size: 11px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--tbc-ink-faint);
}

.tbc-select,
.tbc-input {
  font-family: var(--tbc-font-body);
  font-size: 15px;
  color: var(--tbc-ink);
  background: var(--tbc-well);
  border: 1px solid var(--tbc-border);
  border-radius: 8px;
  padding: 10px 12px;
  width: 100%;
  appearance: none;
  -webkit-appearance: none;
  transition: border-color 120ms ease, box-shadow 120ms ease;
}

.tbc-select {
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='8' viewBox='0 0 12 8'%3E%3Cpath d='M1 1l5 5 5-5' stroke='%23b3a28c' stroke-width='1.6' fill='none' stroke-linecap='round' stroke-linejoin='round'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 12px center;
  padding-right: 32px;
}

.tbc-input:focus, .tbc-select:focus {
  border-color: var(--tbc-glow-dim);
  box-shadow: 0 0 0 3px var(--tbc-glow-soft);
  outline: none;
}

.tbc-input-unit {
  position: relative;
  display: flex;
  align-items: center;
}

.tbc-input-unit .tbc-input { padding-right: 54px; }

.tbc-unit {
  position: absolute;
  right: 12px;
  font-family: var(--tbc-font-mono);
  font-size: 11.5px;
  color: var(--tbc-ink-faint);
  pointer-events: none;
}

.tbc-hint {
  grid-column: 1 / -1;
  margin: 2px 0 0;
  font-size: 12.5px;
  color: var(--tbc-ink-faint);
  min-height: 1.4em;
}

.tbc-hint strong { color: var(--tbc-ink-muted); font-weight: 600; }

/* ---------- Class A / Class AB reference strip ---------- */
.tbc-reference {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1px;
  background: var(--tbc-border-soft);
  border: 1px solid var(--tbc-border-soft);
  border-radius: var(--tbc-radius-sm);
  overflow: hidden;
  margin: 18px 0;
}

.tbc-ref-col {
  background: rgba(34, 27, 21, 0.8);
  padding: 14px 16px;
}

.tbc-ref-col h3 {
  font-family: var(--tbc-font-display);
  font-size: 12.5px;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--tbc-ink-muted);
  margin: 0 0 10px;
}

.tbc-ref-row {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 10px;
  padding: 5px 0;
  border-top: 1px dashed var(--tbc-border-soft);
  font-size: 12.5px;
}

.tbc-ref-row:first-of-type { border-top: none; }

.tbc-ref-row dt { color: var(--tbc-ink-muted); font-weight: 400; }
.tbc-ref-row dt span {
  display: inline-block;
  margin-left: 5px;
  font-family: var(--tbc-font-mono);
  font-size: 10.5px;
  color: var(--tbc-ink-faint);
}
.tbc-ref-row dd {
  margin: 0;
  font-family: var(--tbc-font-mono);
  font-size: 13.5px;
  color: var(--tbc-ink);
  white-space: nowrap;
}

/* ---------- gauge class selector ---------- */
.tbc-class-select {
  max-width: 200px;
  margin: 0 0 18px;
}

/* ---------- mode dial ---------- */
.tbc-modes {
  display: flex;
  gap: 6px;
  border-bottom: 1px solid var(--tbc-border-soft);
  margin-bottom: 18px;
  overflow-x: auto;
  scrollbar-width: none;
}
.tbc-modes::-webkit-scrollbar { display: none; }

.tbc-mode-btn {
  flex: none;
  font-family: var(--tbc-font-display);
  font-size: 13px;
  font-weight: 500;
  color: var(--tbc-ink-faint);
  background: transparent;
  border: none;
  border-bottom: 2px solid transparent;
  padding: 10px 6px 12px;
  margin-right: 14px;
  cursor: pointer;
  white-space: nowrap;
  transition: color 120ms ease, border-color 120ms ease;
}

.tbc-mode-btn:hover { color: var(--tbc-ink-muted); }

.tbc-mode-btn.is-active {
  color: var(--tbc-glow);
  border-bottom-color: var(--tbc-glow);
}

/* ---------- calculation panel ---------- */
.tbc-panel {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 22px;
  align-items: start;
}

.tbc-mode-group {
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.tbc-mode-group[hidden] { display: none; }

.tbc-mode-copy {
  font-size: 12.5px;
  color: var(--tbc-ink-faint);
  margin: 0 0 2px;
  line-height: 1.5;
}

/* ---------- readout / gauge ---------- */
.tbc-readout {
  position: relative;
  background: var(--tbc-panel-raised);
  border: 1px solid var(--tbc-border-soft);
  border-radius: var(--tbc-radius-sm);
  padding: 16px 18px 14px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 6px;
  overflow: hidden;
}

.tbc-tube-frame {
  position: absolute;
  top: 4px;
  left: 50%;
  transform: translateX(-50%);
  width: 92%;
  opacity: 0.3;
  z-index: 0;
  pointer-events: none;
}

.tbc-tube-photo { width: 100%; height: auto; display: block; }

.tbc-gauge-wrap {
  position: relative;
  z-index: 1;
  width: 100%;
  max-width: 240px;
}

.tbc-gauge {
  width: 100%; height: auto; display: block;
  filter: drop-shadow(0 1px 1px rgba(0, 0, 0, 0.9)) drop-shadow(0 0 4px rgba(0, 0, 0, 0.9));
}

.tbc-gauge-figure {
  font-family: var(--tbc-font-mono);
  font-size: 22px;
  fill: #ffffff;
}

.tbc-gauge-label {
  font-family: var(--tbc-font-body);
  font-size: 9.5px;
  fill: var(--tbc-ink);
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

.tbc-gauge-tick {
  font-family: var(--tbc-font-mono);
  font-size: 8.5px;
  fill: var(--tbc-ink);
}

.tbc-readout-values {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px 16px;
  width: 100%;
  margin-top: 2px;
}

.tbc-big-value {
  text-align: center;
  padding-top: 8px;
  border-top: 1px solid var(--tbc-border-soft);
}

.tbc-big-value .tbc-num {
  display: block;
  font-family: var(--tbc-font-mono);
  font-size: 19px;
  color: var(--tbc-glow);
  text-shadow: 0 0 18px var(--tbc-glow-soft), 0 1px 3px rgba(0, 0, 0, 0.9);
  line-height: 1.2;
}

.tbc-big-value small {
  display: block;
  font-size: 10px;
  color: var(--tbc-ink);
  text-shadow: 0 1px 3px rgba(0, 0, 0, 0.9);
/*  text-transform: uppercase;*/
  letter-spacing: 0.05em;
  margin-top: 2px;
}

.tbc-steps {
  width: 100%;
  margin: 6px 0 0;
  padding-top: 10px;
  border-top: 1px dashed var(--tbc-border-soft);
  font-size: 11.5px;
  color: var(--tbc-ink);
  text-shadow: 0 1px 4px rgba(0, 0, 0, 0.95), 0 0 6px rgba(0, 0, 0, 0.8);
  display: flex;
  flex-direction: column;
  gap: 4px;
}
.tbc-steps span { color: #ffffff; font-family: var(--tbc-font-mono); }

/* ---------- bench reference table ---------- */
.tbc-bench {
  margin-top: 22px;
  border-top: 1px solid var(--tbc-border-soft);
  padding-top: 14px;
}

.tbc-bench summary {
  cursor: pointer;
  font-family: var(--tbc-font-display);
  font-size: 13px;
  color: var(--tbc-ink-muted);
  list-style: none;
  display: flex;
  align-items: center;
  gap: 6px;
}
.tbc-bench summary::-webkit-details-marker { display: none; }
.tbc-bench summary::before {
  content: "";
  width: 7px;
  height: 7px;
  border-right: 1.5px solid currentColor;
  border-bottom: 1.5px solid currentColor;
  transform: rotate(-45deg);
  transition: transform 150ms ease;
}
.tbc-bench[open] summary::before { transform: rotate(45deg); }

.tbc-bench-table {
  width: 100%;
  border-collapse: collapse;
  margin-top: 12px;
  font-size: 12.5px;
}
.tbc-bench-table th, .tbc-bench-table td {
  text-align: left;
  padding: 7px 10px;
  border-bottom: 1px solid var(--tbc-border-soft);
}
.tbc-bench-table th {
  font-family: var(--tbc-font-mono);
  font-size: 10.5px;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--tbc-ink-faint);
  font-weight: 400;
}
.tbc-bench-table td { color: var(--tbc-ink-muted); font-family: var(--tbc-font-mono); }
.tbc-bench-table td:first-child { font-family: var(--tbc-font-body); color: var(--tbc-ink); }

/* ---------- footer ---------- */
.tbc-footer {
  margin-top: 18px;
  font-size: 11.5px;
  color: var(--tbc-ink-faint);
  line-height: 1.6;
}

/* ---------- responsive ---------- */
@media (max-width: 640px) {
  .tbc { padding: 20px 16px; }
  .tbc-setup { grid-template-columns: 1fr; }
  .tbc-reference { grid-template-columns: 1fr; }
  .tbc-panel { grid-template-columns: 1fr; }
  .tbc-title { font-size: 22px; }
  .tbc-tube-frame { width: 90%; }

  /* Four measurement-method tabs don't fit one scrollable row on a phone
     without the person having to notice and drag it — lay them out as a
     2x2 grid instead so all four are visible at once, no interaction
     needed to discover the hidden ones. */
  .tbc-modes {
    display: grid;
    grid-template-columns: 1fr 1fr;
    overflow-x: visible;
    gap: 2px 10px;
  }
  .tbc-mode-btn {
    margin-right: 0;
    text-align: center;
    white-space: normal;
    line-height: 1.25;
    font-size: 12px;
    padding: 8px 4px 10px;
    border-bottom: 2px solid var(--tbc-border-soft);
  }
  .tbc-mode-btn.is-active { border-bottom-color: var(--tbc-glow); }
}

@media (prefers-reduced-motion: reduce) {
  .tbc-select, .tbc-input, .tbc-mode-btn { transition: none; }
  .tbc-gauge * { transition: none !important; }
}