/* ============================================================
   TruckerKit — main.css
   Production stylesheet. No external dependencies.
   Mobile-first, breakpoints at 768 px and 1024 px.
   ============================================================ */

/* ---------- CSS Custom Properties ---------- */
:root {
  --color-cta:        #D85A30;
  --color-cta-hover:  #C04E28;
  --color-dark:       #1A1A2E;
  --color-bg:         #F7F5F0;
  --color-text:       #2C2C2A;
  --color-accent:     #3B6D11;
  --color-card-border:#D3D1C7;
  --color-white:      #FFFFFF;
  --color-light-gray: #ECEAE4;
  --color-mid-gray:   #888;
  --font-stack:       -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --radius:           6px;
  --shadow-sm:        0 1px 3px rgba(0,0,0,.08);
  --shadow-md:        0 4px 12px rgba(0,0,0,.1);
  --max-width:        1140px;
  --nav-height:       60px;
}

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

html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }

body {
  font-family: var(--font-stack);
  color: var(--color-text);
  background: var(--color-bg);
  line-height: 1.6;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
}

img { max-width: 100%; height: auto; display: block; }

a { color: var(--color-cta); text-decoration: none; }
a:hover { text-decoration: underline; }

h1, h2, h3, h4 { line-height: 1.25; margin-bottom: .5em; }
h1 { font-size: 2rem; }
h2 { font-size: 1.5rem; }
h3 { font-size: 1.2rem; }

p { margin-bottom: 1em; }

ul, ol { padding-left: 1.25em; margin-bottom: 1em; }

.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1rem;
}

/* ---------- Skip Link (a11y) ---------- */
.skip-link {
  position: absolute;
  left: -9999px;
  top: 0;
  background: var(--color-cta);
  color: var(--color-white);
  padding: .5em 1em;
  z-index: 1000;
}
.skip-link:focus { left: 0; }

/* ============================================================
   NAVIGATION — sticky, hamburger on mobile
   ============================================================ */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--color-dark);
  box-shadow: var(--shadow-md);
}

.nav-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: var(--nav-height);
}

.nav-brand {
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--color-white);
  letter-spacing: .5px;
  text-decoration: none;
}
.nav-brand span { color: var(--color-cta); }

/* Hamburger toggle — checkbox trick */
.nav-toggle { display: none; }
.nav-toggle-label {
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  cursor: pointer;
  width: 28px;
  height: 28px;
}
.nav-toggle-label span {
  display: block;
  height: 2px;
  background: var(--color-white);
  border-radius: 2px;
  transition: transform .25s ease, opacity .25s ease;
}

.nav-links {
  list-style: none;
  padding: 0;
  margin: 0;
  display: none;
  flex-direction: column;
  position: absolute;
  top: var(--nav-height);
  left: 0;
  right: 0;
  background: var(--color-dark);
  box-shadow: var(--shadow-md);
}
.nav-links li { border-top: 1px solid rgba(255,255,255,.08); }
.nav-links a {
  display: block;
  padding: .85rem 1rem;
  color: var(--color-white);
  font-size: .95rem;
  text-decoration: none;
  transition: background .15s;
}
.nav-links a:hover,
.nav-links a:focus {
  background: rgba(255,255,255,.06);
  text-decoration: none;
}
.nav-links .nav-bmc a { color: var(--color-cta); }

/* Open state */
.nav-toggle:checked ~ .nav-links { display: flex; }
.nav-toggle:checked ~ .nav-toggle-label span:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}
.nav-toggle:checked ~ .nav-toggle-label span:nth-child(2) { opacity: 0; }
.nav-toggle:checked ~ .nav-toggle-label span:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

/* Desktop nav */
@media (min-width: 768px) {
  .nav-toggle-label { display: none; }
  .nav-links {
    display: flex;
    flex-direction: row;
    position: static;
    background: none;
    box-shadow: none;
    gap: .25rem;
  }
  .nav-links li { border: none; }
  .nav-links a { padding: .5rem .75rem; border-radius: var(--radius); }
}

/* ============================================================
   HERO
   ============================================================ */
.hero {
  background: var(--color-dark);
  color: var(--color-white);
  padding: 3rem 1rem 2.5rem;
  text-align: center;
}
.hero h1 { font-size: 1.75rem; margin-bottom: .5em; }
.hero .tagline {
  font-size: 1.05rem;
  color: rgba(255,255,255,.8);
  max-width: 640px;
  margin: 0 auto 1.5rem;
  line-height: 1.5;
}

/* Category quick-jump buttons */
.hero-categories {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: .5rem;
  margin-bottom: 1.5rem;
}
.hero-categories a {
  display: inline-block;
  padding: .45rem .9rem;
  background: rgba(255,255,255,.1);
  color: var(--color-white);
  border-radius: 999px;
  font-size: .85rem;
  text-decoration: none;
  transition: background .15s;
}
.hero-categories a:hover {
  background: var(--color-cta);
  text-decoration: none;
}

/* 12V filter toggle — signature feature, prominent */
.filter-bar {
  display: flex;
  justify-content: center;
  padding: 1rem;
  background: var(--color-light-gray);
  border-bottom: 1px solid var(--color-card-border);
}
.filter-toggle {
  display: flex;
  align-items: center;
  gap: .65rem;
  font-weight: 600;
  font-size: 1rem;
  cursor: pointer;
  user-select: none;
  color: var(--color-text);
}
.filter-toggle input[type="checkbox"] { display: none; }
.toggle-track {
  position: relative;
  width: 48px;
  height: 26px;
  background: var(--color-card-border);
  border-radius: 999px;
  transition: background .2s;
  flex-shrink: 0;
}
.toggle-track::after {
  content: '';
  position: absolute;
  top: 3px;
  left: 3px;
  width: 20px;
  height: 20px;
  border-radius: 50%;
  background: var(--color-white);
  transition: transform .2s;
  box-shadow: var(--shadow-sm);
}
.filter-toggle input:checked + .toggle-track {
  background: var(--color-accent);
}
.filter-toggle input:checked + .toggle-track::after {
  transform: translateX(22px);
}
.filter-toggle .toggle-label-text {}

/* When filter active, non-12v cards get hidden via JS adding .hidden */
.product-card.hidden { display: none; }

.visible-count {
  font-size: 0.875rem;
  color: var(--color-text);
  opacity: 0.7;
  margin-left: 1rem;
}

@media (min-width: 768px) {
  .hero { padding: 4rem 1rem 3rem; }
  .hero h1 { font-size: 2.25rem; }
}

/* ============================================================
   SECTIONS
   ============================================================ */
.section {
  padding: 2.5rem 0;
}
.section + .section {
  border-top: 1px solid var(--color-card-border);
}
.section-title {
  font-size: 1.5rem;
  margin-bottom: 1.25rem;
}

/* ============================================================
   PRODUCT CARD GRID
   ============================================================ */
.product-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.25rem;
}
@media (min-width: 768px) {
  .product-grid { grid-template-columns: repeat(2, 1fr); }
}
@media (min-width: 1024px) {
  .product-grid { grid-template-columns: repeat(3, 1fr); }
}

.product-card {
  background: var(--color-white);
  border: 1px solid var(--color-card-border);
  border-radius: var(--radius);
  padding: 1.25rem;
  display: flex;
  flex-direction: column;
  transition: box-shadow .15s;
}
.product-card:hover { box-shadow: var(--shadow-md); }

.product-name {
  font-size: 1.1rem;
  margin-bottom: .4em;
}
.product-desc {
  font-size: .92rem;
  color: #555;
  flex: 1;
}
.product-badges {
  display: flex;
  flex-wrap: wrap;
  gap: .4rem;
  margin-bottom: .75rem;
}
.product-rating {
  margin-bottom: .75rem;
  font-size: .9rem;
}

/* ---------- Badges ---------- */
.badge {
  display: inline-block;
  padding: .2rem .55rem;
  font-size: .75rem;
  font-weight: 600;
  border-radius: 999px;
  line-height: 1.4;
}
.badge-12v {
  background: var(--color-accent);
  color: var(--color-white);
}
.badge-fit {
  background: var(--color-light-gray);
  color: var(--color-text);
  border: 1px solid var(--color-card-border);
}
.badge-inverter {
  background: #6C5B7B;
  color: var(--color-white);
}
.badge-usb {
  background: #2980B9;
  color: var(--color-white);
}
.badge-battery {
  background: #7F8C8D;
  color: var(--color-white);
}
.badge-category {
  background: var(--color-dark);
  color: var(--color-white);
}

/* ============================================================
   BUTTONS
   ============================================================ */
.btn {
  display: inline-block;
  padding: .65rem 1.25rem;
  font-size: .95rem;
  font-weight: 600;
  text-align: center;
  border: none;
  border-radius: var(--radius);
  cursor: pointer;
  text-decoration: none;
  transition: background .15s, transform .1s;
  line-height: 1.4;
}
.btn:hover { text-decoration: none; transform: translateY(-1px); }
.btn:active { transform: translateY(0); }

.btn-amazon {
  background: var(--color-cta);
  color: var(--color-white);
  width: 100%;
}
.btn-amazon:hover { background: var(--color-cta-hover); color: var(--color-white); }

.btn-primary {
  background: var(--color-cta);
  color: var(--color-white);
}
.btn-primary:hover { background: var(--color-cta-hover); color: var(--color-white); }

.btn-secondary {
  background: var(--color-light-gray);
  color: var(--color-text);
  border: 1px solid var(--color-card-border);
}
.btn-secondary:hover { background: var(--color-card-border); }

.btn-bmc {
  background: var(--color-cta);
  color: var(--color-white);
  font-size: 1.05rem;
}
.btn-bmc:hover { background: var(--color-cta-hover); color: var(--color-white); }

.btn:disabled, .btn[disabled] {
  opacity: .55;
  cursor: not-allowed;
  transform: none;
}

/* ============================================================
   STAR RATINGS — CSS-only, no images
   ============================================================ */
.stars {
  display: inline-flex;
  gap: 2px;
  font-size: 1.15rem;
  color: var(--color-card-border);
  line-height: 1;
}
.stars .star { position: relative; }
.stars .star::before { content: '\2605'; } /* filled star glyph */
.stars .star.filled { color: #E8A317; }
.stars .star.half { color: #E8A317; }
.stars .star.half::after {
  content: '\2605';
  position: absolute;
  left: 0; top: 0;
  width: 50%;
  overflow: hidden;
  color: #E8A317;
}
.stars .star.empty { color: var(--color-card-border); }

/* Large stars for summary bar */
.stars-lg { font-size: 1.6rem; }

/* ============================================================
   INTERACTIVE STAR RATING WIDGET (review form)
   ============================================================ */
.star-rating-widget {
  display: inline-flex;
  flex-direction: row-reverse;
  gap: 2px;
  font-size: 1.75rem;
}
.star-rating-widget input { display: none; }
.star-rating-widget label {
  cursor: pointer;
  color: var(--color-card-border);
  transition: color .1s;
  line-height: 1;
}
.star-rating-widget label::before { content: '\2605'; }
/* Highlight on hover and check */
.star-rating-widget input:checked ~ label { color: #E8A317; }
.star-rating-widget label:hover,
.star-rating-widget label:hover ~ label { color: #E8A317; }

/* ============================================================
   REVIEW CARDS
   ============================================================ */
.review-summary-bar {
  display: flex;
  align-items: center;
  gap: 1rem;
  flex-wrap: wrap;
  padding: 1.25rem;
  background: var(--color-white);
  border: 1px solid var(--color-card-border);
  border-radius: var(--radius);
  margin-bottom: 1.5rem;
}
.review-summary-bar .avg-rating {
  font-size: 2rem;
  font-weight: 700;
  color: var(--color-text);
}
.review-summary-bar .review-count {
  font-size: .95rem;
  color: var(--color-mid-gray);
}

.review-controls {
  display: flex;
  flex-wrap: wrap;
  gap: .75rem;
  align-items: center;
  margin-bottom: 1.25rem;
}
.review-controls select,
.review-controls button {
  padding: .45rem .75rem;
  font-size: .9rem;
  border: 1px solid var(--color-card-border);
  border-radius: var(--radius);
  background: var(--color-white);
  cursor: pointer;
  font-family: var(--font-stack);
}
.review-controls button.active {
  background: var(--color-dark);
  color: var(--color-white);
  border-color: var(--color-dark);
}

.review-list { margin-bottom: 2.5rem; }

.review-card {
  background: var(--color-white);
  border: 1px solid var(--color-card-border);
  border-radius: var(--radius);
  padding: 1.25rem;
  margin-bottom: 1rem;
}
.review-card .review-header {
  display: flex;
  align-items: center;
  gap: .75rem;
  flex-wrap: wrap;
  margin-bottom: .5rem;
}
.review-card .review-headline {
  font-weight: 700;
  font-size: 1.05rem;
  margin-bottom: .35em;
}
.review-card .review-body {
  font-size: .93rem;
  margin-bottom: .5em;
  color: #444;
}
.review-card .review-meta {
  font-size: .82rem;
  color: var(--color-mid-gray);
}

.review-empty {
  text-align: center;
  padding: 2rem 1rem;
  color: var(--color-mid-gray);
  font-style: italic;
}

/* ============================================================
   REVIEW FORM
   ============================================================ */
.review-form-section {
  background: var(--color-white);
  border: 1px solid var(--color-card-border);
  border-radius: var(--radius);
  padding: 1.5rem;
}
.review-form-section h2 { margin-bottom: 1rem; }

.form-group {
  margin-bottom: 1rem;
}
.form-group label {
  display: block;
  font-weight: 600;
  font-size: .9rem;
  margin-bottom: .3rem;
}
.form-group input[type="text"],
.form-group textarea,
.form-group select {
  width: 100%;
  padding: .55rem .75rem;
  font-size: .95rem;
  border: 1px solid var(--color-card-border);
  border-radius: var(--radius);
  background: var(--color-bg);
  font-family: var(--font-stack);
  transition: border-color .15s;
}
.form-group input:focus,
.form-group textarea:focus,
.form-group select:focus {
  outline: none;
  border-color: var(--color-cta);
  box-shadow: 0 0 0 3px rgba(216,90,48,.15);
}
.form-group textarea { resize: vertical; min-height: 100px; }
.form-group .char-count {
  font-size: .78rem;
  color: var(--color-mid-gray);
  text-align: right;
  margin-top: .2rem;
}

.form-message {
  padding: .75rem 1rem;
  border-radius: var(--radius);
  font-size: .9rem;
  margin-bottom: 1rem;
}
.form-message.success {
  background: #E8F5E9;
  color: #2E7D32;
  border: 1px solid #A5D6A7;
}
.form-message.error {
  background: #FFEBEE;
  color: #C62828;
  border: 1px solid #EF9A9A;
}

/* Spinner */
.spinner {
  display: inline-block;
  width: 16px;
  height: 16px;
  border: 2px solid rgba(255,255,255,.3);
  border-top-color: var(--color-white);
  border-radius: 50%;
  animation: spin .6s linear infinite;
  vertical-align: middle;
  margin-left: .5rem;
}
@keyframes spin { to { transform: rotate(360deg); } }

/* ============================================================
   STATS PAGE
   ============================================================ */
.stats-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1rem;
  margin-bottom: 2rem;
}
@media (min-width: 768px) {
  .stats-grid { grid-template-columns: repeat(3, 1fr); }
}

.metric-card {
  background: var(--color-white);
  border: 1px solid var(--color-card-border);
  border-radius: var(--radius);
  padding: 1.25rem;
  text-align: center;
}
.metric-card .metric-value {
  font-size: 2.25rem;
  font-weight: 700;
  color: var(--color-cta);
  line-height: 1.2;
}
.metric-card .metric-label {
  font-size: .85rem;
  color: var(--color-mid-gray);
  text-transform: uppercase;
  letter-spacing: .5px;
  margin-top: .25rem;
}

.chart-container {
  background: var(--color-white);
  border: 1px solid var(--color-card-border);
  border-radius: var(--radius);
  padding: 1.25rem;
  margin-bottom: 1.5rem;
}
.chart-container h3 { margin-bottom: .75rem; }
.chart-container canvas { width: 100% !important; }

.stats-table {
  width: 100%;
  border-collapse: collapse;
  background: var(--color-white);
  border: 1px solid var(--color-card-border);
  border-radius: var(--radius);
  overflow: hidden;
}
.stats-table th,
.stats-table td {
  text-align: left;
  padding: .65rem .85rem;
  border-bottom: 1px solid var(--color-card-border);
  font-size: .9rem;
}
.stats-table th {
  background: var(--color-light-gray);
  font-weight: 600;
  font-size: .82rem;
  text-transform: uppercase;
  letter-spacing: .4px;
}
.stats-table tr:last-child td { border-bottom: none; }

.stats-error {
  text-align: center;
  padding: 2rem;
  color: var(--color-mid-gray);
}

/* ============================================================
   GUIDE PAGES — Article Typography
   ============================================================ */
.guide-article {
  max-width: 720px;
  margin: 0 auto;
  padding: 2rem 1rem 3rem;
}
.guide-article h1 {
  font-size: 1.75rem;
  margin-bottom: .25em;
}
.guide-meta {
  font-size: .85rem;
  color: var(--color-mid-gray);
  margin-bottom: 1.75rem;
  padding-bottom: 1rem;
  border-bottom: 1px solid var(--color-card-border);
}
.guide-article h2 {
  margin-top: 2rem;
  margin-bottom: .6em;
  font-size: 1.35rem;
}
.guide-article h3 {
  margin-top: 1.5rem;
  margin-bottom: .5em;
}
.guide-article p {
  margin-bottom: 1em;
  line-height: 1.7;
}
.guide-article ul, .guide-article ol {
  margin-bottom: 1.25em;
  line-height: 1.7;
}
.guide-article li { margin-bottom: .35em; }
.guide-article strong { color: var(--color-text); }

/* Callout / tip box */
.callout {
  background: #FFF8E1;
  border-left: 4px solid var(--color-cta);
  padding: 1rem 1.25rem;
  margin: 1.5rem 0;
  border-radius: 0 var(--radius) var(--radius) 0;
  font-size: .93rem;
}
.callout-title {
  font-weight: 700;
  margin-bottom: .25em;
}

/* Guide products callout */
.guide-products-callout {
  background: var(--color-light-gray);
  border: 1px solid var(--color-card-border);
  border-radius: var(--radius);
  padding: 1.25rem;
  margin: 2rem 0;
}
.guide-products-callout h3 { margin-bottom: .5em; }
.guide-products-callout ul { list-style: none; padding: 0; margin: 0; }
.guide-products-callout li { margin-bottom: .4em; }
.guide-products-callout a { font-weight: 600; }

/* Related guides */
.guide-related {
  border-top: 1px solid var(--color-card-border);
  padding-top: 1.5rem;
  margin-top: 2.5rem;
}
.guide-related h3 { margin-bottom: .75em; }
.guide-related ul { list-style: none; padding: 0; }
.guide-related li { margin-bottom: .5em; }
.guide-related a {
  font-weight: 600;
  display: inline-flex;
  align-items: center;
  gap: .3rem;
}

/* Guide card grid on index page */
.guide-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1rem;
}
@media (min-width: 768px) {
  .guide-grid { grid-template-columns: repeat(2, 1fr); }
}
@media (min-width: 1024px) {
  .guide-grid { grid-template-columns: repeat(3, 1fr); }
}
.guide-card {
  background: var(--color-white);
  border: 1px solid var(--color-card-border);
  border-radius: var(--radius);
  padding: 1.25rem;
  transition: box-shadow .15s;
}
.guide-card:hover { box-shadow: var(--shadow-md); }
.guide-card h3 { margin-bottom: .4em; font-size: 1.05rem; }
.guide-card p { font-size: .9rem; color: #555; margin-bottom: .75em; }
.guide-card a { font-weight: 600; font-size: .9rem; }

@media (min-width: 768px) {
  .guide-article h1 { font-size: 2rem; }
}

/* ============================================================
   ALERTS
   ============================================================ */
.alert {
  padding: .75rem 1rem;
  border-radius: var(--radius);
  margin-bottom: 1rem;
  font-size: .9rem;
}
.alert-info {
  background: #E3F2FD;
  color: #1565C0;
  border: 1px solid #90CAF9;
}
.alert-warning {
  background: #FFF8E1;
  color: #F57F17;
  border: 1px solid #FFE082;
}
.alert-success {
  background: #E8F5E9;
  color: #2E7D32;
  border: 1px solid #A5D6A7;
}
.alert-error {
  background: #FFEBEE;
  color: #C62828;
  border: 1px solid #EF9A9A;
}

/* ============================================================
   FOOTER
   ============================================================ */
.site-footer {
  background: var(--color-dark);
  color: rgba(255,255,255,.7);
  padding: 2rem 1rem;
  font-size: .85rem;
  text-align: center;
  line-height: 1.7;
  margin-top: 2rem;
}
.site-footer a {
  color: rgba(255,255,255,.9);
  text-decoration: underline;
}
.site-footer a:hover { color: var(--color-cta); }
.footer-links {
  margin-bottom: .5rem;
}
.footer-links a { margin: 0 .4rem; }
.footer-disclosure {
  max-width: 600px;
  margin: .75rem auto 0;
  font-size: .78rem;
  color: rgba(255,255,255,.5);
}

/* ============================================================
   UTILITY CLASSES
   ============================================================ */
.text-center { text-align: center; }
.text-muted { color: var(--color-mid-gray); }
.mt-1 { margin-top: .5rem; }
.mt-2 { margin-top: 1rem; }
.mt-3 { margin-top: 1.5rem; }
.mb-1 { margin-bottom: .5rem; }
.mb-2 { margin-bottom: 1rem; }
.mb-3 { margin-bottom: 1.5rem; }
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0,0,0,0);
  white-space: nowrap;
  border: 0;
}

/* Visually hidden but accessible focus indicator for form errors */
.visually-hidden { position: absolute; left: -9999px; }

/* ============================================================
   RESPONSIVE FINE-TUNING
   ============================================================ */
@media (max-width: 767px) {
  .hero h1 { font-size: 1.5rem; }
  .hero .tagline { font-size: .95rem; }
  .review-summary-bar { flex-direction: column; text-align: center; }
  .metric-card .metric-value { font-size: 1.75rem; }
}

@media (min-width: 1024px) {
  .container { padding: 0 2rem; }
  .section { padding: 3rem 0; }
}