/* ============================================================
   PRODUCT.CSS — BangDinhNhom Theme
   Product Card | Single Product | Gallery | Tabs
   Specs Table | Archive | Filters | Quote Form
   ============================================================ */

/* ── PRODUCT CARD ────────────────────────────────────────── */
.product-card {
  background: #fff;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  display: flex;
  flex-direction: column;
  text-decoration: none;
  color: var(--color-text);
  transition: box-shadow .25s, transform .25s;
  position: relative;
}

.product-card:hover {
  box-shadow: var(--shadow-lg);
  transform: translateY(-4px);
}

.product-card-image-wrap {
  position: relative;
  aspect-ratio: 4/3;
  background: var(--color-bg);
  overflow: hidden;
}

.product-card-image-wrap img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform .4s;
}

.product-card:hover .product-card-image-wrap img { transform: scale(1.06); }

.product-card-image-placeholder {
  width: 100%;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  background: linear-gradient(135deg, var(--color-primary-bg) 0%, #dbe8f5 100%);
}

.product-card-image-placeholder svg {
  width: 56px;
  height: 56px;
  color: var(--color-primary);
  opacity: .3;
}

.product-card-badge {
  position: absolute;
  top: .75rem;
  left: .75rem;
  font-size: .65rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: .06em;
  padding: .25rem .6rem;
  border-radius: 100px;
  background: var(--color-primary);
  color: #fff;
  z-index: 2;
}

.product-card-badge.badge-hot {
  background: #ef4444;
}

.product-card-badge.badge-new {
  background: #10b981;
}

.product-card-badge.badge-sale {
  background: var(--color-accent);
}

.product-card-category-badge {
  position: absolute;
  top: .75rem;
  right: .75rem;
  font-size: .62rem;
  font-weight: 600;
  color: rgba(255,255,255,.9);
  background: rgba(0,0,0,.4);
  backdrop-filter: blur(4px);
  padding: .2rem .55rem;
  border-radius: 100px;
  z-index: 2;
  text-transform: uppercase;
  letter-spacing: .04em;
}

.product-card-body {
  padding: 1.1rem;
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: .5rem;
}

.product-card-category {
  font-size: .7rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: .08em;
  color: var(--color-primary);
}

.product-card-title {
  font-family: var(--font-display);
  font-size: .95rem;
  font-weight: 700;
  color: var(--color-text);
  line-height: 1.3;
  transition: color .2s;
}

.product-card:hover .product-card-title { color: var(--color-primary); }

.product-card-excerpt {
  font-size: .8rem;
  color: var(--color-text-muted);
  line-height: 1.5;
  flex: 1;
}

.product-card-specs {
  display: flex;
  flex-wrap: wrap;
  gap: .35rem;
  padding-top: .25rem;
}

.spec-tag {
  display: inline-flex;
  align-items: center;
  gap: .25rem;
  font-family: var(--font-mono);
  font-size: .68rem;
  color: var(--color-text-muted);
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  padding: .2rem .5rem;
  border-radius: var(--radius-sm);
}

.product-card-footer {
  padding: .75rem 1.1rem;
  border-top: 1px solid var(--color-border);
  display: flex;
  align-items: center;
  gap: .5rem;
  flex-wrap: wrap;
}

.product-card-cta-view {
  flex: 1;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: .35rem;
  padding: .55rem .9rem;
  background: var(--color-primary);
  color: #fff;
  font-size: .78rem;
  font-weight: 600;
  border-radius: var(--radius-sm);
  text-decoration: none;
  transition: background .2s;
  white-space: nowrap;
}

.product-card-cta-view:hover { background: var(--color-primary-dark); color: #fff; }
.product-card-cta-view svg { width: 13px; height: 13px; }

.product-card-cta-quote {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: .35rem;
  padding: .55rem .9rem;
  background: transparent;
  color: var(--color-accent);
  font-size: .78rem;
  font-weight: 600;
  border: 1.5px solid var(--color-accent);
  border-radius: var(--radius-sm);
  text-decoration: none;
  transition: background .2s, color .2s;
  white-space: nowrap;
}

.product-card-cta-quote:hover {
  background: var(--color-accent);
  color: #fff;
}

.product-card-cta-quote svg { width: 13px; height: 13px; }

/* ── ARCHIVE PAGE ─────────────────────────────────────────── */
.archive-header {
  background: var(--color-primary-dark);
  padding: 3rem 0 2rem;
  color: #fff;
  position: relative;
  overflow: hidden;
}

.archive-header::before {
  content: '';
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(255,255,255,.03) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255,255,255,.03) 1px, transparent 1px);
  background-size: 40px 40px;
}

.archive-header-inner { position: relative; z-index: 1; }

.archive-header-label {
  font-size: .72rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: .12em;
  color: var(--color-accent);
  margin-bottom: .5rem;
  display: flex;
  align-items: center;
  gap: .5rem;
}

.archive-header-label::before {
  content: '';
  display: block;
  width: 20px;
  height: 2px;
  background: var(--color-accent);
}

.archive-header-title {
  font-family: var(--font-display);
  font-size: clamp(1.5rem, 3vw, 2.5rem);
  font-weight: 900;
  text-transform: uppercase;
  letter-spacing: .03em;
  color: #fff;
  margin-bottom: .5rem;
}

.archive-header-desc {
  font-size: .95rem;
  color: rgba(255,255,255,.7);
  max-width: 600px;
  line-height: 1.6;
}

/* Filter bar */
.archive-filter-bar {
  background: #fff;
  border-bottom: 1px solid var(--color-border);
  position: sticky;
  top: 68px;
  z-index: 50;
  box-shadow: 0 2px 8px rgba(0,0,0,.05);
}

.archive-filter-inner {
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: .75rem 0;
  flex-wrap: wrap;
}

.filter-label {
  font-size: .78rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: .06em;
  color: var(--color-text-muted);
  flex-shrink: 0;
}

.filter-tabs {
  display: flex;
  gap: .35rem;
  flex-wrap: wrap;
  flex: 1;
}

.filter-tab {
  display: inline-flex;
  align-items: center;
  gap: .3rem;
  padding: .4rem .9rem;
  font-size: .8rem;
  font-weight: 600;
  border-radius: 100px;
  border: 1.5px solid var(--color-border);
  background: transparent;
  color: var(--color-text-muted);
  cursor: pointer;
  transition: all .2s;
  text-decoration: none;
  white-space: nowrap;
}

.filter-tab:hover,
.filter-tab.active {
  border-color: var(--color-primary);
  background: var(--color-primary);
  color: #fff;
}

.filter-count {
  font-size: .68rem;
  background: rgba(255,255,255,.2);
  padding: .05rem .35rem;
  border-radius: 100px;
}

.filter-tab:not(.active) .filter-count {
  background: var(--color-bg);
  color: var(--color-text-muted);
}

.archive-sort {
  margin-left: auto;
  flex-shrink: 0;
}

.archive-sort select {
  font-size: .8rem;
  padding: .4rem .75rem;
  border: 1.5px solid var(--color-border);
  border-radius: var(--radius-sm);
  background: #fff;
  color: var(--color-text);
  cursor: pointer;
  appearance: none;
  padding-right: 1.5rem;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 24 24' fill='none' stroke='%236b7280' stroke-width='2'%3E%3Cpath d='m6 9 6 6 6-6'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right .5rem center;
}

.archive-layout {
  display: grid;
  grid-template-columns: 260px 1fr;
  gap: 2rem;
  padding: 2rem 0;
}

/* Sidebar filters */
.archive-sidebar {
  position: sticky;
  top: calc(68px + 56px + 1rem);
  align-self: start;
  max-height: calc(100vh - 200px);
  overflow-y: auto;
}

.sidebar-filter-group {
  margin-bottom: 1.5rem;
  background: #fff;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  overflow: hidden;
}

.sidebar-filter-title {
  font-family: var(--font-display);
  font-size: .82rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: .06em;
  color: var(--color-text);
  padding: .9rem 1rem;
  background: var(--color-bg);
  border-bottom: 1px solid var(--color-border);
  display: flex;
  align-items: center;
  justify-content: space-between;
  cursor: pointer;
}

.sidebar-filter-title svg {
  width: 14px;
  height: 14px;
  color: var(--color-text-muted);
  transition: transform .2s;
}

.sidebar-filter-group.open .sidebar-filter-title svg { transform: rotate(180deg); }

.sidebar-filter-body {
  padding: .75rem 1rem;
  display: none;
}

.sidebar-filter-group.open .sidebar-filter-body { display: block; }

.sidebar-filter-item {
  display: flex;
  align-items: center;
  gap: .6rem;
  padding: .35rem 0;
  cursor: pointer;
  font-size: .85rem;
  color: var(--color-text);
}

.sidebar-filter-item input[type="checkbox"] {
  width: 14px;
  height: 14px;
  accent-color: var(--color-primary);
  cursor: pointer;
}

.sidebar-filter-item-count {
  margin-left: auto;
  font-size: .72rem;
  color: var(--color-text-muted);
  background: var(--color-bg);
  padding: .1rem .4rem;
  border-radius: 100px;
}

.archive-main {}

.archive-result-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 1.25rem;
}

.archive-result-count {
  font-size: .85rem;
  color: var(--color-text-muted);
}

.archive-result-count strong { color: var(--color-text); }

/* ── SINGLE PRODUCT ──────────────────────────────────────── */
.product-single-header {
  background: var(--color-primary-dark);
  padding: 2rem 0;
  color: #fff;
  position: relative;
  overflow: hidden;
}

.product-single-header::before {
  content: '';
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(255,255,255,.03) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255,255,255,.03) 1px, transparent 1px);
  background-size: 40px 40px;
  pointer-events: none;
}

.product-single-layout {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 3rem;
  padding: 3rem 0;
  align-items: start;
}

/* Gallery */
.product-gallery {
  position: sticky;
  top: calc(68px + 1rem);
}

.product-gallery-main {
  border-radius: var(--radius-lg);
  overflow: hidden;
  background: var(--color-bg);
  aspect-ratio: 4/3;
  margin-bottom: .75rem;
  cursor: zoom-in;
  position: relative;
}

.product-gallery-main img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform .3s;
}

.product-gallery-main:hover img { transform: scale(1.04); }

.product-gallery-main-placeholder {
  width: 100%;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  background: linear-gradient(135deg, var(--color-primary-bg) 0%, #dbe8f5 100%);
}

.product-gallery-main-placeholder svg {
  width: 80px;
  height: 80px;
  color: var(--color-primary);
  opacity: .25;
}

.product-gallery-zoom-hint {
  position: absolute;
  bottom: .75rem;
  right: .75rem;
  background: rgba(0,0,0,.5);
  color: rgba(255,255,255,.9);
  font-size: .68rem;
  padding: .3rem .6rem;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  gap: .3rem;
  pointer-events: none;
}

.product-gallery-zoom-hint svg { width: 12px; height: 12px; }

.product-gallery-thumbs {
  display: flex;
  gap: .5rem;
  overflow-x: auto;
  padding-bottom: .25rem;
}

.product-gallery-thumb {
  flex-shrink: 0;
  width: 72px;
  height: 72px;
  border-radius: var(--radius-sm);
  overflow: hidden;
  border: 2px solid var(--color-border);
  cursor: pointer;
  transition: border-color .2s;
  background: var(--color-bg);
}

.product-gallery-thumb img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.product-gallery-thumb:hover,
.product-gallery-thumb.active {
  border-color: var(--color-primary);
}

/* Product info panel */
.product-info {}

.product-info-category {
  display: flex;
  align-items: center;
  gap: .5rem;
  margin-bottom: .75rem;
  flex-wrap: wrap;
}

.product-info-category a {
  font-size: .72rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: .08em;
  color: var(--color-primary);
  background: var(--color-primary-bg);
  padding: .25rem .65rem;
  border-radius: 100px;
  text-decoration: none;
  transition: background .2s;
}

.product-info-category a:hover { background: #c6daf2; }

.product-brand-badge {
  font-size: .72rem;
  font-weight: 600;
  color: var(--color-text-muted);
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  padding: .25rem .65rem;
  border-radius: 100px;
}

.product-info-title {
  font-family: var(--font-display);
  font-size: clamp(1.4rem, 2.5vw, 2rem);
  font-weight: 800;
  color: var(--color-text);
  line-height: 1.2;
  margin-bottom: 1rem;
  text-transform: uppercase;
  letter-spacing: .02em;
}

.product-info-excerpt {
  font-size: .95rem;
  color: var(--color-text-muted);
  line-height: 1.65;
  margin-bottom: 1.5rem;
  padding-bottom: 1.5rem;
  border-bottom: 1px solid var(--color-border);
}

/* Quick specs */
.product-quick-specs {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: .6rem;
  margin-bottom: 1.5rem;
}

.quick-spec-item {
  display: flex;
  align-items: center;
  gap: .6rem;
  padding: .7rem .9rem;
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
}

.quick-spec-icon {
  width: 28px;
  height: 28px;
  border-radius: var(--radius-sm);
  background: var(--color-primary-bg);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.quick-spec-icon svg {
  width: 14px;
  height: 14px;
  color: var(--color-primary);
}

.quick-spec-text {
  flex: 1;
  min-width: 0;
}

.quick-spec-label {
  font-size: .68rem;
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: .05em;
  display: block;
}

.quick-spec-value {
  font-family: var(--font-mono);
  font-size: .82rem;
  font-weight: 700;
  color: var(--color-text);
  display: block;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

/* Trust badges */
.product-trust-badges {
  display: flex;
  flex-wrap: wrap;
  gap: .5rem;
  margin-bottom: 1.5rem;
}

.trust-badge {
  display: inline-flex;
  align-items: center;
  gap: .35rem;
  font-size: .72rem;
  font-weight: 600;
  color: var(--color-text-muted);
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  padding: .35rem .75rem;
  border-radius: 100px;
}

.trust-badge svg {
  width: 14px;
  height: 14px;
  color: #10b981;
}

/* Action buttons */
.product-actions {
  display: flex;
  gap: .75rem;
  flex-wrap: wrap;
  padding-top: 1.5rem;
  border-top: 1px solid var(--color-border);
}

.btn-quote-now {
  flex: 1;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: .5rem;
  padding: .9rem 1.5rem;
  background: var(--color-accent);
  color: #fff;
  font-size: .95rem;
  font-weight: 700;
  border-radius: var(--radius-sm);
  text-decoration: none;
  cursor: pointer;
  border: none;
  transition: background .2s, transform .15s;
  box-shadow: 0 4px 14px rgba(255,152,0,.35);
}

.btn-quote-now:hover {
  background: #e65100;
  transform: translateY(-2px);
  color: #fff;
}

.btn-quote-now svg { width: 18px; height: 18px; }

.btn-call-now {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: .5rem;
  padding: .9rem 1.5rem;
  background: var(--color-primary);
  color: #fff;
  font-size: .95rem;
  font-weight: 700;
  border-radius: var(--radius-sm);
  text-decoration: none;
  transition: background .2s;
}

.btn-call-now:hover { background: var(--color-primary-dark); color: #fff; }
.btn-call-now svg { width: 18px; height: 18px; }

.btn-download-spec {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: .5rem;
  padding: .9rem 1rem;
  border: 1.5px solid var(--color-border);
  background: #fff;
  color: var(--color-text-muted);
  font-size: .85rem;
  font-weight: 600;
  border-radius: var(--radius-sm);
  text-decoration: none;
  transition: border-color .2s, color .2s;
}

.btn-download-spec:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
}

.btn-download-spec svg { width: 16px; height: 16px; }

/* ── PRODUCT TABS ─────────────────────────────────────────── */
.product-tabs-section { padding: 3rem 0; }

.product-tabs-nav {
  display: flex;
  gap: 0;
  border-bottom: 2px solid var(--color-border);
  margin-bottom: 2rem;
  overflow-x: auto;
}

.product-tab-btn {
  display: inline-flex;
  align-items: center;
  gap: .4rem;
  padding: .75rem 1.25rem;
  font-size: .85rem;
  font-weight: 600;
  color: var(--color-text-muted);
  background: none;
  border: none;
  border-bottom: 2px solid transparent;
  cursor: pointer;
  transition: color .2s, border-color .2s;
  white-space: nowrap;
  margin-bottom: -2px;
}

.product-tab-btn:hover { color: var(--color-primary); }

.product-tab-btn.active {
  color: var(--color-primary);
  border-bottom-color: var(--color-primary);
}

.product-tab-btn svg { width: 15px; height: 15px; }

.product-tab-panel { display: none; }
.product-tab-panel.active { display: block; }

/* Specs table */
.specs-table {
  width: 100%;
  border-collapse: collapse;
  font-size: .88rem;
}

.specs-table th,
.specs-table td {
  padding: .75rem 1rem;
  text-align: left;
  border-bottom: 1px solid var(--color-border);
  vertical-align: top;
}

.specs-table thead th {
  background: var(--color-primary);
  color: #fff;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: .8rem;
  text-transform: uppercase;
  letter-spacing: .06em;
}

.specs-table thead th:first-child { border-radius: var(--radius-sm) 0 0 0; }
.specs-table thead th:last-child { border-radius: 0 var(--radius-sm) 0 0; }

.specs-table tbody tr:nth-child(even) td { background: var(--color-bg); }

.specs-table tbody tr:hover td { background: var(--color-primary-bg); }

.specs-table td:first-child {
  font-weight: 600;
  color: var(--color-text);
  width: 40%;
  font-size: .82rem;
  text-transform: uppercase;
  letter-spacing: .03em;
}

.specs-table td:last-child {
  font-family: var(--font-mono);
  color: var(--color-primary);
}

/* Applications list in tab */
.product-applications-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: .75rem;
}

.product-application-item {
  display: flex;
  align-items: center;
  gap: .6rem;
  padding: .8rem;
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  font-size: .85rem;
  color: var(--color-text);
}

.product-application-item svg {
  width: 16px;
  height: 16px;
  color: var(--color-primary);
  flex-shrink: 0;
}

/* Guide / installation tab */
.installation-guide {
  max-width: 720px;
}

.installation-step {
  display: flex;
  gap: 1.25rem;
  margin-bottom: 2rem;
  position: relative;
}

.installation-step:not(:last-child)::after {
  content: '';
  position: absolute;
  left: 19px;
  top: 40px;
  bottom: -2rem;
  width: 2px;
  background: var(--color-border);
}

.step-number {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background: var(--color-primary);
  color: #fff;
  font-family: var(--font-display);
  font-size: 1rem;
  font-weight: 800;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  position: relative;
  z-index: 1;
}

.step-content {}

.step-title {
  font-family: var(--font-display);
  font-size: .95rem;
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: .4rem;
  text-transform: uppercase;
}

.step-desc {
  font-size: .88rem;
  color: var(--color-text-muted);
  line-height: 1.6;
}

/* Video embed */
.product-video-wrap {
  border-radius: var(--radius-lg);
  overflow: hidden;
  aspect-ratio: 16/9;
  background: #000;
}

.product-video-wrap iframe {
  width: 100%;
  height: 100%;
  border: none;
  display: block;
}

/* Certificates */
.product-certs-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1rem;
}

.cert-item {
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  overflow: hidden;
  text-align: center;
}

.cert-item img {
  width: 100%;
  height: 120px;
  object-fit: contain;
  padding: .75rem;
  background: var(--color-bg);
  display: block;
}

.cert-item-label {
  padding: .5rem;
  font-size: .72rem;
  color: var(--color-text-muted);
  font-weight: 600;
  border-top: 1px solid var(--color-border);
}

/* ── QUOTE FORM INLINE ───────────────────────────────────── */
.product-quote-section {
  background: var(--color-primary-dark);
  border-radius: var(--radius-lg);
  padding: 2rem;
  color: #fff;
  position: relative;
  overflow: hidden;
}

.product-quote-section::before {
  content: '';
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(255,255,255,.03) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255,255,255,.03) 1px, transparent 1px);
  background-size: 30px 30px;
  pointer-events: none;
}

.product-quote-title {
  font-family: var(--font-display);
  font-size: 1.25rem;
  font-weight: 800;
  text-transform: uppercase;
  margin-bottom: .4rem;
  position: relative;
}

.product-quote-desc {
  font-size: .85rem;
  color: rgba(255,255,255,.7);
  margin-bottom: 1.5rem;
  position: relative;
}

/* ── FAQ ACCORDION (product page only) ───────────────────── */
.single-san-pham .faq-list {
  display: flex;
  flex-direction: column;
  gap: .5rem;
}

.single-san-pham .faq-item {
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  overflow: hidden;
  background: #fff;
}

.single-san-pham .faq-question {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 1.1rem 1.25rem;
  cursor: pointer;
  background: none;
  border: none;
  width: 100%;
  text-align: left;
  font-family: var(--font-body);
  font-size: .92rem;
  font-weight: 700;
  color: var(--color-text);
  transition: color .2s, background .2s;
}

.single-san-pham .faq-question:hover {
  color: var(--color-primary);
  background: var(--color-primary-bg);
}

.single-san-pham .faq-item.open .faq-question {
  color: var(--color-primary);
  background: var(--color-primary-bg);
  border-bottom: 1px solid var(--color-border);
}

.single-san-pham .faq-icon {
  width: 20px;
  height: 20px;
  border-radius: 50%;
  background: var(--color-primary-bg);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  transition: background .2s, transform .3s;
}

.single-san-pham .faq-item.open .faq-icon {
  background: var(--color-primary);
  transform: rotate(45deg);
}

.single-san-pham .faq-icon svg {
  width: 12px;
  height: 12px;
  color: var(--color-primary);
}

.single-san-pham .faq-item.open .faq-icon svg { color: #fff; }

.single-san-pham .faq-answer {
  display: none;
  padding: 1.1rem 1.25rem;
  font-size: .88rem;
  color: var(--color-text-muted);
  line-height: 1.65;
}

.single-san-pham .faq-item.open .faq-answer { display: block; }

/* ── RELATED PRODUCTS ────────────────────────────────────── */
.related-products-section {
  padding: 3rem 0;
  background: var(--color-bg);
}

/* ── RESPONSIVE PRODUCT ──────────────────────────────────── */
@media (max-width: 1024px) {
  .product-single-layout { grid-template-columns: 1fr; gap: 2rem; }
  .product-gallery { position: static; }
  .archive-layout { grid-template-columns: 1fr; }
  .archive-sidebar { position: static; max-height: none; }
  .product-applications-grid { grid-template-columns: repeat(2, 1fr); }
  .product-certs-grid { grid-template-columns: repeat(3, 1fr); }
}

@media (max-width: 768px) {
  .product-quick-specs { grid-template-columns: 1fr; }
  .product-actions { flex-direction: column; }
  .btn-quote-now, .btn-call-now { justify-content: center; }
  .product-applications-grid { grid-template-columns: 1fr; }
  .product-certs-grid { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 640px) {
  .product-tabs-nav { gap: 0; }
  .product-tab-btn { padding: .65rem .9rem; font-size: .78rem; }
  .specs-table { font-size: .78rem; }
  .specs-table th, .specs-table td { padding: .6rem .75rem; }
}