/* ===========================================
   RESPONSIVE - Mobile-first breakpoints
   =========================================== */

/* ---- Tablet and below (≤900px) ---- */
@media (max-width: 900px) {
  .nav-buttons {
    display: none;
  }
  .lang-toggle {
    display: none;
  }
  .menu-button {
    display: block;
  }
  .dropdown-menu {
    display: none; /* toggled by JS */
  }

  .header__logo-img {
    width: 60px;
    height: 60px;
  }
  .header__title {
    font-size: 20px;
  }
  .header__subtitle {
    font-size: 11px;
  }

  .banner {
    min-height: clamp(280px, 45vw, 380px);
    padding-left: 30px;
  }
  .banner__title {
    font-size: clamp(1.2rem, 3.5vw, 1.8rem);
  }
  .banner__subtitle {
    font-size: clamp(0.65rem, 1.3vw, 0.85rem);
  }
  .banner__cta {
    padding: 10px 28px;
    font-size: 13px;
    letter-spacing: 2px;
  }

  .product-detail-view {
    flex-direction: column;
  }
  .product-detail-image {
    flex: none;
    text-align: center;
  }
  .product-detail-image img {
    max-width: 200px;
    margin: 0 auto;
  }

  /* Slider: items-per-view handled by JS custom property */
  .slider__track {
    padding: 16px 12px;
    gap: 16px;
  }

  .footer__top {
    grid-template-columns: 1fr 1fr;
    gap: var(--space-xl);
  }
}

/* ---- Mobile (≤768px) ---- */
@media (max-width: 768px) {
  .header {
    padding: 10px 20px;
  }

  .banner {
    min-height: clamp(260px, 50vw, 360px);
    padding: 0;
    background-attachment: scroll;
    background-image: url('../icons/hero-dark-banner-mobile.jpg');
    background-position: center center;
    background-size: cover;
    align-items: flex-end;
    justify-content: flex-start;
  }
  .banner__overlay {
    background:
      linear-gradient(90deg, rgba(0,0,0,0.65) 0%, rgba(0,0,0,0.35) 40%, transparent 65%);
  }
  .banner__content {
    position: absolute;
    top: 50%;
    left: 0;
    transform: translateY(-50%);
    max-width: 60%;
    align-items: flex-start;
    text-align: left;
    gap: 6px;
    padding: var(--space-md) var(--space-md) var(--space-md) var(--space-md);
  }
  .banner__content::before {
    display: none;
  }
  .banner__title {
    font-size: clamp(1rem, 4.5vw, 1.3rem);
    letter-spacing: 1.5px;
    text-shadow: 0 2px 10px rgba(0,0,0,0.9);
  }
  .banner__subtitle {
    font-size: 0.55rem;
    letter-spacing: 1px;
    line-height: 1.4;
    text-shadow: 0 1px 6px rgba(0,0,0,0.9);
  }
  .banner__cta {
    margin-top: 2px;
    padding: 7px 18px;
    font-size: 0.65rem;
    letter-spacing: 1.5px;
    white-space: nowrap;
  }

  .content {
    padding: var(--space-md);
  }

  .section__content {
    padding: var(--space-lg);
  }

  .home-features {
    grid-template-columns: 1fr;
  }

  .about-stats {
    grid-template-columns: repeat(2, 1fr);
  }

  .about-values {
    grid-template-columns: 1fr;
  }

  .about-mission {
    flex-direction: column;
    align-items: center;
    text-align: center;
    padding: var(--space-lg);
  }

  .about-page {
    gap: var(--space-xl);
  }

  .products-grid {
    grid-template-columns: repeat(auto-fill, minmax(160px, 1fr));
    gap: var(--space-md);
  }

  .contact-methods {
    grid-template-columns: 1fr;
  }

  .social-links {
    gap: var(--space-md);
  }

  .footer__top {
    grid-template-columns: 1fr;
    gap: var(--space-lg);
    text-align: center;
  }
  .footer__col-title::after {
    left: 50%;
    transform: translateX(-50%);
  }
  .footer__social-icons {
    justify-content: center;
  }
  .footer__logo {
    justify-content: center;
  }

  .oil-finder-header {
    flex-direction: column;
    align-items: stretch;
  }
  .vehicle-option {
    text-align: center;
  }
  .search-input-container {
    flex-direction: column;
  }
  .categories-container {
    gap: var(--space-sm);
  }
  .category-card {
    min-width: 100px;
    padding: var(--space-md) var(--space-sm);
  }
  .oils-grid {
    grid-template-columns: repeat(auto-fill, minmax(110px, 1fr));
  }

  .slider__image {
    height: 180px;
  }
  .slider__track {
    gap: 14px;
    padding: 14px 10px;
  }

  .vehicle-info {
    padding: var(--space-md);
  }

  .accordion__body {
    font-size: var(--fs-small);
  }
}

/* ---- Small Mobile (≤480px) ---- */
@media (max-width: 480px) {
  .header {
    padding: 8px 15px;
  }
  .header__logo-img {
    width: 45px;
    height: 45px;
  }
  .header__title {
    font-size: 18px;
  }
  .header__subtitle {
    display: none;
  }
  .header--scrolled .header__logo-img {
    width: 35px;
    height: 35px;
  }

  .banner {
    min-height: clamp(220px, 48vw, 320px);
  }
  .banner__title {
    font-size: clamp(0.85rem, 4vw, 1.1rem);
    letter-spacing: 1px;
  }
  .banner__subtitle {
    font-size: 0.5rem;
  }
  .banner__cta {
    padding: 6px 16px;
    font-size: 0.6rem;
    letter-spacing: 1px;
    gap: 5px;
    margin-top: 2px;
  }

  .content {
    padding: var(--space-sm);
  }

  .section__content {
    padding: var(--space-md);
    border-radius: var(--radius-md);
  }

  .products-grid {
    grid-template-columns: 1fr 1fr;
    gap: var(--space-sm);
  }

  .about-stats {
    grid-template-columns: repeat(2, 1fr);
    gap: var(--space-sm);
  }
  .about-stat {
    padding: var(--space-md) var(--space-sm);
  }
  .about-stat__number {
    font-size: 1.5rem;
  }
  .about-value {
    padding: var(--space-lg);
  }
  .about-page {
    gap: var(--space-lg);
  }

  .slider {
    border-radius: var(--radius-md);
  }
  .slider__track {
    gap: 12px;
    padding: 12px 8px;
  }
  .slider__image {
    height: 160px;
  }
  .slider__nav {
    width: 36px;
    height: 36px;
  }
  .slider__nav svg {
    width: 16px;
    height: 16px;
  }
  .slider__nav--prev { left: 6px; }
  .slider__nav--next { right: 6px; }
  .slider__dot {
    width: 6px;
    height: 6px;
  }
  .slider__dot.active {
    width: 18px;
  }
  .slider__counter {
    font-size: 10px;
  }

  .loading-logo-wrap {
    width: 110px;
    height: 110px;
  }
  .loading-bar-container {
    width: 220px;
  }
  .loading-brand-text {
    font-size: 22px;
    letter-spacing: 6px;
  }

  .home-welcome h2 {
    font-size: 1.3rem;
  }

  .product-detail-name {
    font-size: 1.3rem;
  }

  .toast {
    max-width: 280px;
    font-size: 13px;
  }
  .toast-container {
    left: 10px;
    right: 10px;
    bottom: 10px;
  }

  .back-to-top {
    width: 40px;
    height: 40px;
    font-size: 20px;
    bottom: 20px;
    right: 20px;
  }
}

/* ---- Extra Small (≤360px) ---- */
@media (max-width: 360px) {
  .header__logo-img {
    width: 38px;
    height: 38px;
    margin-right: 8px;
  }
  .header__title {
    font-size: 16px;
  }

  .banner {
    min-height: clamp(200px, 45vw, 280px);
  }

  .products-grid {
    grid-template-columns: 1fr;
  }

  .section__content {
    padding: var(--space-sm);
  }

  .dropdowns-container select,
  .search-input {
    font-size: 14px;
    padding: 8px 10px;
  }
  .vehicle-option {
    padding: 10px 20px;
    font-size: var(--fs-small);
  }
  .vehicle-info {
    flex-direction: column;
    text-align: center;
  }
  .oils-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

/* ---- Large Desktop (≥1440px) ---- */
@media (min-width: 1440px) {
  .content {
    max-width: 1400px;
  }
  /* slider items-per-view handled by JS */
}

/* ---- Certification & ASTM responsive ---- */
@media (max-width: 768px) {
  .cert-badges { grid-template-columns: 1fr 1fr; }
  .astm-strip__items { gap: var(--space-sm); }
  .astm-item { padding: var(--space-xs) var(--space-md); }
  .footer__cert-badges { justify-content: center; }
}
@media (max-width: 480px) {
  .cert-badges { grid-template-columns: 1fr; }
  .astm-strip { padding: var(--space-md); }
}

/* ---- Reduced motion preference ---- */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
  .reveal-on-scroll {
    opacity: 1;
    transform: none;
  }
}