/* ==============================================================================
   Ferrite Bead Optimizer — Tool CSS
   Follows ESD Protection Analyzer CSS architecture and Rising Edge design tokens.
============================================================================== */

/* ── Page layout ──────────────────────────────────────────────────────────── */
.fb-page {
  padding-bottom: 80px;
}

/* ── Kicker / eyebrow ─────────────────────────────────────────────────────── */
.fb-kicker {
  display: inline-block;
  font: 700 var(--text-xs, 0.75rem)/1 var(--font-sans, system-ui);
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--primary-400, #60a5fa);
  margin-bottom: 10px;
}

/* ── Hero ─────────────────────────────────────────────────────────────────── */
.fb-hero {
  padding: calc(var(--nav-height, 64px) + 36px) 40px 40px;
  max-width: 1280px;
  margin: 0 auto;
}
.fb-hero h1 {
  font-size: clamp(2rem, 5vw, 3.25rem);
  font-weight: 800;
  letter-spacing: -0.02em;
  line-height: 1.1;
  margin: 10px 0 14px;
}
.fb-hero p {
  max-width: 680px;
  color: var(--text-sub, #cbd5e1);
  font-size: var(--text-md, 1rem);
  line-height: 1.7;
}
.fb-hero-grid {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 40px;
  align-items: start;
}
.fb-hero-actions {
  display: flex;
  flex-direction: column;
  gap: 10px;
  padding-top: 60px;
  min-width: 200px;
}
.fb-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 14px;
}

/* ── Intro strip ──────────────────────────────────────────────────────────── */
.fb-intro {
  display: grid;
  grid-template-columns: 1fr 360px;
  gap: 32px;
  max-width: 1280px;
  margin: 0 auto 28px;
  padding: 28px 40px;
}
.fb-intro h2 {
  font-size: var(--text-xl, 1.25rem);
  margin-bottom: 8px;
}
.fb-intro p {
  color: var(--text-sub, #cbd5e1);
  line-height: 1.7;
}

/* ── Workspace grid ───────────────────────────────────────────────────────── */
.fb-workspace {
  display: grid;
  grid-template-columns: 460px minmax(0, 1fr);
  gap: 24px;
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 40px;
  align-items: start;
}
.fb-inputs,
.fb-results {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

/* ── Card anatomy ─────────────────────────────────────────────────────────── */
.fb-card {
  padding: 24px 26px;
}
.fb-card-head {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  margin-bottom: 18px;
  gap: 12px;
}
.fb-card-head > div {
  display: flex;
  align-items: center;
  gap: 10px;
}
.fb-card-head h2 {
  font-size: var(--text-md, 1rem);
  font-weight: 700;
}
.fb-step {
  display: inline-grid;
  place-items: center;
  width: 26px;
  height: 26px;
  border-radius: 50%;
  background: var(--primary-600, #2563eb);
  color: #fff;
  font: 800 var(--text-xs, 0.75rem)/1 var(--font-sans, system-ui);
  flex-shrink: 0;
}
.fb-hint {
  font-size: var(--text-xs, 0.75rem);
  color: var(--text-muted, #94a3b8);
}
.fb-hint.fb-hint-ok {
  color: #34d399;
}
.fb-hint.fb-hint-warn {
  color: #f59e0b;
}
.fb-hint.fb-hint-error {
  color: var(--error, #ef4444);
}

/* ── Form grid ────────────────────────────────────────────────────────────── */
.fb-form-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 14px 16px;
  margin-bottom: 16px;
}
.fb-form-grid-3 {
  grid-template-columns: 1fr 1fr 1fr;
}
.fb-span2 {
  grid-column: span 2;
}
.fb-form-grid label,
.fb-form-grid > label {
  display: flex;
  flex-direction: column;
  gap: 4px;
  font-size: var(--text-sm, 0.875rem);
  font-weight: 600;
  color: var(--text-sub, #cbd5e1);
}
.fb-form-grid label span {
  font-weight: 400;
  color: var(--text-muted, #94a3b8);
  font-size: var(--text-xs, 0.75rem);
}
.fb-form-grid sub {
  font-size: 0.7em;
}
.fb-button-row {
  display: flex;
  gap: 8px;
}
.fb-wide {
  width: 100%;
  justify-content: center;
}

/* ── Topology selector ────────────────────────────────────────────────────── */
.fb-topo-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 10px;
}
.fb-topo-card {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
  padding: 14px 10px;
  border: 1px solid var(--border, rgba(255, 255, 255, 0.07));
  border-radius: var(--radius-md, 8px);
  cursor: pointer;
  transition:
    border-color 0.15s,
    background 0.15s;
  background: var(--bg-alt, #0b1221);
}
.fb-topo-card:has(input:checked) {
  border-color: var(--primary-400, #60a5fa);
  background: rgba(37, 99, 235, 0.07);
}
.fb-topo-card input[type='radio'] {
  display: none;
}
.fb-topo-icon {
  color: var(--text-faint, #64748b);
  line-height: 0;
}
.fb-topo-card:has(input:checked) .fb-topo-icon {
  color: var(--primary-400, #60a5fa);
}
.fb-topo-name {
  font-size: var(--text-sm, 0.875rem);
  font-weight: 700;
}
.fb-topo-desc {
  font-size: var(--text-xs, 0.75rem);
  color: var(--text-muted, #94a3b8);
  text-align: center;
  line-height: 1.4;
}

/* ── Summary stats ────────────────────────────────────────────────────────── */
.fb-stats {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 10px;
  margin-bottom: 18px;
}
.fb-stats > div {
  padding: 10px;
  border: 1px solid var(--border, rgba(255, 255, 255, 0.07));
  border-radius: var(--radius-md, 8px);
  background: var(--bg-alt, #0b1221);
  text-align: center;
}
.fb-stats span {
  display: block;
  font-size: 10px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-muted, #94a3b8);
  margin-bottom: 4px;
}
.fb-stats strong {
  font-size: var(--text-lg, 1.125rem);
  font-weight: 800;
  color: var(--primary-400, #60a5fa);
}
.fb-stats strong.stat-pass {
  color: #34d399;
}
.fb-stats strong.stat-marginal {
  color: #f59e0b;
}
.fb-stats strong.stat-fail {
  color: #ef4444;
}

/* ── Charts ───────────────────────────────────────────────────────────────── */
.fb-chart {
  min-height: 240px;
  border-radius: var(--radius-md, 8px);
  overflow: hidden;
}
.fb-chart-sm {
  min-height: 200px;
}
.fb-chart-md {
  min-height: 220px;
}
.fb-empty {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 200px;
  color: var(--text-faint, #64748b);
  font-size: var(--text-sm, 0.875rem);
  border: 1px dashed var(--border, rgba(255, 255, 255, 0.07));
  border-radius: var(--radius-md, 8px);
  text-align: center;
  padding: 20px;
}

/* ── Export grid ──────────────────────────────────────────────────────────── */
.fb-export-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 10px;
}
.fb-export-grid .btn {
  justify-content: center;
  font-size: var(--text-xs, 0.75rem);
}
.fb-file-label {
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
}
.fb-file-label input[type='file'] {
  display: none;
}

/* ── Comparison table section ─────────────────────────────────────────────── */
.fb-table-section {
  max-width: 1280px;
  margin: 28px auto 0;
  padding: 0 40px;
}
.fb-section-head {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 20px;
  margin-bottom: 20px;
  flex-wrap: wrap;
}
.fb-section-head h2 {
  font-size: var(--text-xl, 1.25rem);
  margin-bottom: 4px;
}
.fb-section-head p {
  font-size: var(--text-sm, 0.875rem);
  color: var(--text-sub, #cbd5e1);
}
.fb-filter-row {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

/* ── Filter chips ─────────────────────────────────────────────────────────── */
.chip {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  padding: 4px 12px;
  border-radius: 9999px;
  font: 700 11px/1 var(--font-sans, system-ui);
  letter-spacing: 0.06em;
  text-transform: uppercase;
  border: 1px solid var(--border, rgba(255, 255, 255, 0.07));
  background: transparent;
  color: var(--text-muted, #94a3b8);
  cursor: pointer;
  transition:
    background 0.15s,
    color 0.15s,
    border-color 0.15s;
}
.chip-active,
.chip:hover {
  background: rgba(37, 99, 235, 0.13);
  color: var(--primary-400, #60a5fa);
  border-color: rgba(37, 99, 235, 0.4);
}
button.chip {
  font-family: var(--font-sans, system-ui);
}

/* Status chips in table */
.status-chip {
  display: inline-block;
  padding: 2px 8px;
  border-radius: 9999px;
  font-size: 10px;
  font-weight: 700;
  letter-spacing: 0.05em;
  text-transform: uppercase;
}
.status-pass {
  background: rgba(52, 211, 153, 0.1);
  color: #34d399;
}
.status-marginal {
  background: rgba(245, 158, 11, 0.1);
  color: #f59e0b;
}
.status-fail {
  background: rgba(239, 68, 68, 0.12);
  color: #f87171;
}

/* Table cell helpers */
.td-mono {
  font-family: var(--font-mono, monospace);
  font-size: 12px;
  font-weight: 600;
  color: var(--primary-400, #60a5fa);
  white-space: nowrap;
}
.fb-no-results {
  padding: 32px;
  text-align: center;
  color: var(--text-faint, #64748b);
  font-size: var(--text-sm, 0.875rem);
  border: 1px dashed var(--border, rgba(255, 255, 255, 0.07));
  border-radius: var(--radius-lg, 12px);
  margin-top: 12px;
}

/* ── Recommendations section ──────────────────────────────────────────────── */
.fb-recs-section {
  max-width: 1280px;
  margin: 28px auto 0;
  padding: 0 40px;
}
.fb-recs-legend {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  align-items: center;
}
.fb-rec-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(340px, 1fr));
  gap: 20px;
}

/* ── Recommendation cards ─────────────────────────────────────────────────── */
.fb-rec-card {
  border: 1px solid var(--border, rgba(255, 255, 255, 0.07));
  border-radius: var(--radius-lg, 12px);
  background: var(--bg-card, #0f1729);
  padding: 22px;
  transition:
    border-color 0.2s,
    box-shadow 0.2s;
  position: relative;
}
.fb-rec-card.fb-rec-top {
  border-color: rgba(37, 99, 235, 0.45);
}
.fb-rec-card:hover {
  border-color: rgba(37, 99, 235, 0.35);
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.25);
}
.fb-rec-rank {
  position: absolute;
  top: 16px;
  right: 16px;
  width: 28px;
  height: 28px;
  display: grid;
  place-items: center;
  border-radius: 50%;
  background: var(--primary-600, #2563eb);
  color: #fff;
  font: 800 var(--text-xs)/1 var(--font-sans);
}
.fb-rec-part {
  font-family: var(--font-mono, monospace);
  font-size: var(--text-md, 1rem);
  font-weight: 700;
  color: var(--text-base, #f1f5f9);
  margin-bottom: 2px;
}
.fb-rec-mfr {
  font-size: var(--text-xs, 0.75rem);
  color: var(--text-muted, #94a3b8);
  margin-bottom: 14px;
}
.fb-rec-params {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 8px;
  margin-bottom: 14px;
}
.fb-rec-param {
  padding: 8px 10px;
  background: var(--bg-alt, #0b1221);
  border-radius: var(--radius-md, 8px);
  border: 1px solid var(--border, rgba(255, 255, 255, 0.07));
}
.fb-rec-param-label {
  font-size: 10px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-muted, #94a3b8);
  margin-bottom: 3px;
}
.fb-rec-param-value {
  font: 700 var(--text-md, 1rem)/1 var(--font-mono, monospace);
  color: var(--text-base, #f1f5f9);
}
.fb-rec-rationale {
  font-size: var(--text-xs, 0.75rem);
  color: var(--text-muted, #94a3b8);
  line-height: 1.6;
  margin-top: 10px;
  padding-top: 10px;
  border-top: 1px solid var(--border, rgba(255, 255, 255, 0.07));
}
.fb-rec-warnings {
  margin-top: 8px;
  display: flex;
  flex-direction: column;
  gap: 4px;
}
.fb-rec-warn-item {
  display: flex;
  align-items: flex-start;
  gap: 6px;
  font-size: var(--text-xs, 0.75rem);
  color: #f59e0b;
  line-height: 1.4;
}
.fb-rec-warn-item::before {
  content: '⚠';
  flex-shrink: 0;
}

/* ── Advanced charts section ──────────────────────────────────────────────── */
.fb-charts-section {
  max-width: 1280px;
  margin: 28px auto 0;
  padding: 0 40px;
}
.fb-chart-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(360px, 1fr));
  gap: 20px;
}

/* ── Layout guidelines ────────────────────────────────────────────────────── */
.fb-layout-section {
  max-width: 1280px;
  margin: 28px auto 0;
  padding: 0 40px;
}
.fb-guidelines-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(290px, 1fr));
  gap: 18px;
}
.fb-guideline-card {
  border: 1px solid var(--border, rgba(255, 255, 255, 0.07));
  border-radius: var(--radius-lg, 12px);
  background: var(--bg-card, #0f1729);
  padding: 22px;
}
.fb-guideline-icon {
  font-size: 1.5rem;
  margin-bottom: 10px;
  display: block;
}
.fb-guideline-card h4 {
  font-size: var(--text-md, 1rem);
  font-weight: 700;
  margin-bottom: 8px;
}
.fb-guideline-card p {
  font-size: var(--text-sm, 0.875rem);
  color: var(--text-sub, #cbd5e1);
  line-height: 1.65;
  margin-bottom: 8px;
}
.fb-guideline-card ul {
  list-style: none;
  padding: 0;
}
.fb-guideline-card li {
  font-size: var(--text-xs, 0.75rem);
  color: var(--text-muted, #94a3b8);
  padding: 3px 0 3px 14px;
  position: relative;
  line-height: 1.5;
}
.fb-guideline-card li::before {
  content: '';
  position: absolute;
  left: 0;
  top: 9px;
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: var(--primary-400, #60a5fa);
}

/* ── Engineering notes ────────────────────────────────────────────────────── */
.fb-learn {
  max-width: 1280px;
  margin: 40px auto 0;
  padding: 0 40px 60px;
}
.fb-learn h2 {
  font-size: var(--text-xl, 1.25rem);
  margin-bottom: 8px;
}
.fb-section-lead {
  color: var(--text-sub, #cbd5e1);
  max-width: 680px;
  margin-bottom: 20px;
  font-size: var(--text-sm, 0.875rem);
  line-height: 1.7;
}
.fb-accordion {
  display: flex;
  flex-direction: column;
  gap: 8px;
}
.fb-accordion details {
  border: 1px solid var(--border, rgba(255, 255, 255, 0.07));
  border-radius: var(--radius-md, 8px);
  background: var(--bg-card, #0f1729);
  overflow: hidden;
}
.fb-accordion summary {
  padding: 14px 18px;
  cursor: pointer;
  font-weight: 700;
  font-size: var(--text-sm, 0.875rem);
  list-style: none;
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.fb-accordion summary::after {
  content: '\25B8';
  font-size: 0.7em;
  color: var(--text-muted, #94a3b8);
  transition: transform 0.2s;
}
.fb-accordion details[open] summary::after {
  transform: rotate(90deg);
}
.fb-accordion p {
  padding: 0 18px 16px;
  font-size: var(--text-sm, 0.875rem);
  color: var(--text-sub, #cbd5e1);
  line-height: 1.7;
  margin: 0;
}

/* ── Breadcrumb ───────────────────────────────────────────────────────────── */
.breadcrumb {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: var(--text-xs, 0.75rem);
  color: var(--text-muted, #94a3b8);
  margin-bottom: 20px;
  flex-wrap: wrap;
}
.breadcrumb a {
  color: var(--text-muted, #94a3b8);
  text-decoration: none;
}
.breadcrumb a:hover {
  color: var(--primary-400, #60a5fa);
}
.breadcrumb span:not(:last-child) {
  color: var(--border, rgba(255, 255, 255, 0.2));
}

/* ── Responsive ───────────────────────────────────────────────────────────── */
@media (max-width: 1100px) {
  .fb-workspace {
    grid-template-columns: 1fr;
  }
  .fb-hero-grid {
    grid-template-columns: 1fr;
  }
  .fb-hero-actions {
    padding-top: 0;
    flex-direction: row;
    flex-wrap: wrap;
  }
  .fb-intro {
    grid-template-columns: 1fr;
  }
  .fb-stats {
    grid-template-columns: repeat(3, 1fr);
  }
  .fb-export-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .fb-form-grid-3 {
    grid-template-columns: 1fr 1fr;
  }
}

@media (max-width: 680px) {
  .fb-hero {
    padding: calc(var(--nav-height, 64px) + 20px) 16px 28px;
  }
  .fb-workspace,
  .fb-table-section,
  .fb-recs-section,
  .fb-charts-section,
  .fb-layout-section,
  .fb-learn {
    padding-left: 16px;
    padding-right: 16px;
  }
  .fb-intro {
    padding: 20px 16px;
  }
  .fb-form-grid {
    grid-template-columns: 1fr;
  }
  .fb-form-grid-3 {
    grid-template-columns: 1fr;
  }
  .fb-span2 {
    grid-column: span 1;
  }
  .fb-stats {
    grid-template-columns: repeat(2, 1fr);
  }
  .fb-topo-grid {
    grid-template-columns: 1fr;
  }
  .fb-rec-grid {
    grid-template-columns: 1fr;
  }
  .fb-chart-grid {
    grid-template-columns: 1fr;
  }
  .fb-guidelines-grid {
    grid-template-columns: 1fr;
  }
  .fb-section-head {
    flex-direction: column;
  }
  .fb-export-grid {
    grid-template-columns: 1fr 1fr;
  }
}

/* ── Print ────────────────────────────────────────────────────────────────── */
@media print {
  .fb-hero-actions,
  #global-nav,
  #global-footer,
  #global-bottom-nav,
  .help-tip,
  .filter-chip,
  .fb-export-grid,
  .fb-accordion,
  .fb-topo-grid {
    display: none !important;
  }
  .fb-workspace {
    grid-template-columns: 1fr;
  }
  .fb-table-section,
  .fb-recs-section,
  .fb-charts-section,
  .fb-layout-section {
    page-break-before: always;
  }
  .fb-rec-grid,
  .fb-guidelines-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .fb-rec-card,
  .fb-guideline-card {
    break-inside: avoid;
  }
  .data-table {
    font-size: 10px;
  }
  .fb-chart {
    min-height: 280px;
  }
}

/* ── Light mode overrides ─────────────────────────────────────────────────── */
html[data-theme='light'] .fb-topo-card {
  background: #f8fafc;
  border-color: #cbd5e1;
}
html[data-theme='light'] .fb-topo-card:has(input:checked) {
  background: rgba(37, 99, 235, 0.04);
  border-color: #2563eb;
}
html[data-theme='light'] .fb-stats > div {
  background: #f8fafc;
  border-color: rgba(0, 0, 0, 0.08);
}
html[data-theme='light'] .fb-rec-card {
  background: #ffffff;
  border-color: rgba(0, 0, 0, 0.08);
}
html[data-theme='light'] .fb-rec-param {
  background: #f1f5f9;
  border-color: rgba(0, 0, 0, 0.08);
}
html[data-theme='light'] .fb-guideline-card {
  background: #ffffff;
  border-color: rgba(0, 0, 0, 0.08);
}
html[data-theme='light'] .fb-accordion details {
  background: #ffffff;
  border-color: rgba(0, 0, 0, 0.08);
}
html[data-theme='light'] .fb-intro p,
html[data-theme='light'] .fb-hero p,
html[data-theme='light'] .fb-accordion p,
html[data-theme='light'] .fb-guideline-card p {
  color: #475569;
}
html[data-theme='light'] .fb-hint {
  color: #64748b;
}
html[data-theme='light'] .fb-hint.fb-hint-ok {
  color: #059669;
}