/* =========================================
   Vyrian Resistor Color Code Calculator
   ========================================= */

:root {
  --vyrian-blue: #4a6580;
  --vyrian-blue-dark: #354b5e;
  --vyrian-blue-light: #6b8da8;
  --vyrian-orange: #e87a2a;
  --vyrian-orange-dark: #cc6620;
  --vyrian-orange-light: #f5a05e;
  --text-primary: #1a2332;
  --text-secondary: #555e6b;
  --text-muted: #8c95a1;
  --bg-page: #f4f6f8;
  --bg-white: #ffffff;
  --bg-card: #ffffff;
  --border-color: #dce1e7;
  --border-radius: 8px;
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.08);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.1);
  --shadow-lg: 0 8px 24px rgba(0,0,0,0.12);
  --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --transition: 0.2s ease;
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html { font-size: 16px; scroll-behavior: smooth; }
body {
  font-family: var(--font-family);
  color: var(--text-primary);
  background: var(--bg-page);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
}

/* ---- Header ---- */
.site-header {
  background: var(--vyrian-blue-dark);
  color: #fff;
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: var(--shadow-md);
}
.header-inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 60px;
}
.logo { display: flex; align-items: center; text-decoration: none; }
.header-nav { display: flex; align-items: center; gap: 24px; }
.header-nav a {
  color: #fff;
  text-decoration: none;
  font-size: 0.9rem;
  font-weight: 500;
  transition: opacity var(--transition);
}
.header-nav a:hover { opacity: 0.85; }
.btn-cta-header {
  background: var(--vyrian-orange) !important;
  color: #fff !important;
  padding: 8px 20px;
  border-radius: 6px;
  font-weight: 600 !important;
  transition: background var(--transition) !important;
}
.btn-cta-header:hover { background: var(--vyrian-orange-dark) !important; }

/* ---- Page Hero ---- */
.page-hero {
  background: linear-gradient(135deg, var(--vyrian-blue-dark) 0%, var(--vyrian-blue) 100%);
  color: #fff;
  padding: 48px 0 40px;
  text-align: center;
}
.page-hero h1 {
  font-size: 2rem;
  font-weight: 700;
  margin-bottom: 12px;
  letter-spacing: -0.02em;
}
.hero-subtitle {
  font-size: 1.05rem;
  opacity: 0.9;
  max-width: 640px;
  margin: 0 auto;
  line-height: 1.6;
}

/* ---- Calculator Layout ---- */
.calculator-layout {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 32px;
  padding-top: 32px;
  padding-bottom: 48px;
  align-items: start;
}

.calc-panel {
  background: var(--bg-card);
  border-radius: var(--border-radius);
  box-shadow: var(--shadow-md);
  padding: 28px;
}

/* ---- Mode Tabs ---- */
.mode-tabs {
  display: flex;
  gap: 0;
  margin-bottom: 24px;
  border-radius: 8px;
  overflow: hidden;
  border: 2px solid var(--vyrian-blue);
}
.mode-tab {
  flex: 1;
  padding: 10px 0;
  border: none;
  background: var(--bg-white);
  color: var(--vyrian-blue);
  font-family: var(--font-family);
  font-size: 0.95rem;
  font-weight: 600;
  cursor: pointer;
  transition: background var(--transition), color var(--transition);
}
.mode-tab:not(:last-child) { border-right: 2px solid var(--vyrian-blue); }
.mode-tab.active {
  background: var(--vyrian-blue);
  color: #fff;
}
.mode-tab:hover:not(.active) { background: #e8eef4; }
.mode-tab:focus-visible { outline: 2px solid var(--vyrian-orange); outline-offset: -2px; }

/* ---- Band Selectors ---- */
.band-selectors { display: flex; flex-direction: column; gap: 16px; }

.band-selector-group {
  display: flex;
  flex-direction: column;
  gap: 6px;
}
.band-selector-group label {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.band-select-wrap {
  position: relative;
}
.band-select {
  width: 100%;
  padding: 10px 40px 10px 42px;
  border: 2px solid var(--border-color);
  border-radius: 6px;
  font-family: var(--font-family);
  font-size: 0.95rem;
  color: var(--text-primary);
  background: var(--bg-white);
  cursor: pointer;
  appearance: none;
  -webkit-appearance: none;
  transition: border-color var(--transition);
}
.band-select:focus { border-color: var(--vyrian-blue); outline: none; }
.band-select:hover { border-color: var(--vyrian-blue-light); }

.band-color-swatch {
  position: absolute;
  left: 12px;
  top: 50%;
  transform: translateY(-50%);
  width: 20px;
  height: 20px;
  border-radius: 4px;
  border: 1px solid rgba(0,0,0,0.15);
  pointer-events: none;
}

.band-select-arrow {
  position: absolute;
  right: 12px;
  top: 50%;
  transform: translateY(-50%);
  pointer-events: none;
  color: var(--text-muted);
}

/* ---- Clear Button ---- */
.btn-clear {
  margin-top: 20px;
  width: 100%;
  padding: 12px;
  border: 2px solid var(--border-color);
  border-radius: 6px;
  background: var(--bg-white);
  color: var(--text-secondary);
  font-family: var(--font-family);
  font-size: 0.95rem;
  font-weight: 600;
  cursor: pointer;
  transition: all var(--transition);
}
.btn-clear:hover { border-color: #c00; color: #c00; }
.btn-clear:focus-visible { outline: 2px solid var(--vyrian-orange); outline-offset: 2px; }

/* ---- Reverse Calculation ---- */
.reverse-section {
  margin-top: 28px;
  padding-top: 24px;
  border-top: 1px solid var(--border-color);
}
.reverse-section h3 {
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: 4px;
  color: var(--text-primary);
}
.reverse-desc {
  font-size: 0.85rem;
  color: var(--text-secondary);
  margin-bottom: 12px;
}
.reverse-input-row {
  display: flex;
  gap: 8px;
  align-items: stretch;
}
.reverse-input {
  flex: 1;
  min-width: 0;
  padding: 10px 14px;
  border: 2px solid var(--border-color);
  border-radius: 6px;
  font-family: var(--font-family);
  font-size: 0.95rem;
  transition: border-color var(--transition);
}
.reverse-input:focus { border-color: var(--vyrian-blue); outline: none; }
.reverse-unit {
  padding: 10px 12px;
  border: 2px solid var(--border-color);
  border-radius: 6px;
  font-family: var(--font-family);
  font-size: 0.95rem;
  background: var(--bg-white);
  cursor: pointer;
  min-width: 70px;
}
.reverse-unit:focus { border-color: var(--vyrian-blue); outline: none; }
.btn-reverse {
  padding: 10px 20px;
  background: var(--vyrian-orange);
  color: #fff;
  border: none;
  border-radius: 6px;
  font-family: var(--font-family);
  font-size: 0.95rem;
  font-weight: 600;
  cursor: pointer;
  white-space: nowrap;
  transition: background var(--transition);
}
.btn-reverse:hover { background: var(--vyrian-orange-dark); }
.btn-reverse:focus-visible { outline: 2px solid var(--vyrian-blue); outline-offset: 2px; }
.reverse-message {
  margin-top: 10px;
  font-size: 0.85rem;
  color: var(--vyrian-orange-dark);
  min-height: 1.3em;
}
.reverse-message.success { color: #16a34a; }

/* ---- Resistor Preview ---- */
.resistor-preview-wrap {
  margin-bottom: 24px;
}
.resistor-preview-wrap h3 {
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: 12px;
}
.resistor-svg {
  width: 100%;
  height: auto;
  max-height: 160px;
}

/* ---- Result Display ---- */
.result-display {
  background: linear-gradient(135deg, var(--vyrian-blue-dark), var(--vyrian-blue));
  color: #fff;
  padding: 24px;
  border-radius: var(--border-radius);
  text-align: center;
  margin-bottom: 24px;
}
.result-label {
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  opacity: 0.8;
  margin-bottom: 6px;
}
.result-value {
  font-size: 1.6rem;
  font-weight: 700;
  letter-spacing: -0.01em;
  word-break: break-word;
}
.result-value.placeholder { opacity: 0.6; font-size: 1.1rem; font-weight: 400; }

/* ---- CTA Cards ---- */
.cta-cards { display: flex; flex-direction: column; gap: 12px; }
.cta-card {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 16px;
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius);
  text-decoration: none;
  color: var(--text-primary);
  transition: all var(--transition);
}
.cta-card:hover { border-color: var(--vyrian-orange); box-shadow: var(--shadow-sm); transform: translateY(-1px); }
.cta-card.cta-highlight { border-color: var(--vyrian-orange); background: #fff8f3; }
.cta-icon { font-size: 1.6rem; flex-shrink: 0; }
.cta-text strong {
  display: block;
  font-size: 0.95rem;
  margin-bottom: 2px;
  color: var(--text-primary);
}
.cta-text small {
  font-size: 0.8rem;
  color: var(--text-secondary);
}

/* ---- Educational Section ---- */
.edu-section {
  background: var(--bg-white);
  padding: 56px 0;
  border-top: 1px solid var(--border-color);
}
.edu-section h2 {
  font-size: 1.6rem;
  font-weight: 700;
  margin-bottom: 32px;
  text-align: center;
  color: var(--text-primary);
}
.edu-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
}
.edu-card {
  padding: 24px;
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius);
  background: var(--bg-page);
}
.edu-card h3 {
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: 12px;
  color: var(--vyrian-blue-dark);
}
.edu-card p { font-size: 0.9rem; color: var(--text-secondary); margin-bottom: 10px; }
.edu-card p:last-child { margin-bottom: 0; }
.edu-card ul {
  padding-left: 20px;
  font-size: 0.9rem;
  color: var(--text-secondary);
}
.edu-card li { margin-bottom: 6px; }
.edu-card li:last-child { margin-bottom: 0; }

/* Color reference table */
.color-ref-table-wrap { overflow-x: auto; }
.color-ref-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.82rem;
}
.color-ref-table th, .color-ref-table td {
  padding: 7px 10px;
  text-align: left;
  border-bottom: 1px solid var(--border-color);
  white-space: nowrap;
}
.color-ref-table th {
  font-weight: 600;
  color: var(--text-secondary);
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}
.color-dot {
  display: inline-block;
  width: 14px;
  height: 14px;
  border-radius: 3px;
  vertical-align: middle;
  margin-right: 6px;
}

/* ---- Footer ---- */
.site-footer {
  background: var(--vyrian-blue-dark);
  color: #fff;
  padding: 32px 0;
}
.footer-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 16px;
}
.footer-brand { font-size: 0.9rem; opacity: 0.9; }
.footer-links { display: flex; gap: 20px; }
.footer-links a { color: #fff; text-decoration: none; font-size: 0.85rem; opacity: 0.8; }
.footer-links a:hover { opacity: 1; }
.footer-copy { font-size: 0.8rem; opacity: 0.6; }

/* ---- Responsive ---- */
@media (max-width: 900px) {
  .calculator-layout {
    grid-template-columns: 1fr;
    gap: 20px;
  }
  .page-hero h1 { font-size: 1.6rem; }
  .hero-subtitle { font-size: 0.95rem; }
  .edu-grid { grid-template-columns: 1fr; }
}
@media (max-width: 600px) {
  .header-inner { padding: 0 16px; }
  .header-nav { gap: 12px; }
  .header-nav a { font-size: 0.82rem; }
  .calc-panel { padding: 20px 16px; }
  .page-hero { padding: 32px 0 28px; }
  .page-hero h1 { font-size: 1.35rem; }
  .result-value { font-size: 1.3rem; }
  .reverse-input-row { flex-wrap: wrap; }
  .reverse-input { flex-basis: 100%; }
  .footer-inner { flex-direction: column; text-align: center; }
}

/* Focus visible for accessibility */
:focus-visible { outline: 2px solid var(--vyrian-orange); outline-offset: 2px; }
button:focus:not(:focus-visible) { outline: none; }