/* ==========================================================================
   PERFECT ECOTECH - RESPONSIVE STYLES
   Breakpoints: 1280px, 1024px, 768px, 480px, 360px
   CRITICAL RULE: NEVER REDUCE VISIBLE FONT BELOW 14PX (0.875rem)
   ========================================================================== */

/* Large Tablets & Small Desktops (<= 1024px) */
@media (max-width: 1024px) {
  :root {
    --fs-hero: 2.75rem; /* 44px */
    --fs-3xl: 2rem;     /* 32px */
  }

  .grid-4 {
    grid-template-columns: repeat(2, 1fr);
  }

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

  .hero-grid {
    grid-template-columns: 1fr;
    gap: var(--spacing-8);
  }

  .footer-grid {
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-8);
  }

  .footer-brand-col {
    grid-column: span 2;
  }
}

/* Tablets (<= 768px) */
@media (max-width: 768px) {
  :root {
    --fs-hero: 2.25rem; /* 36px */
    --fs-3xl: 1.875rem; /* 30px */
    --fs-2xl: 1.5rem;   /* 24px */
    --spacing-16: 3rem; /* 48px */
    --spacing-20: 3.5rem; /* 56px */
  }

  .header-actions .btn {
    display: none;
  }

  .mobile-nav-toggle {
    display: block;
  }

  .nav-menu {
    position: fixed;
    top: 80px;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: #FFFFFF;
    flex-direction: column;
    align-items: stretch;
    padding: var(--spacing-6);
    gap: var(--spacing-3);
    border-top: 1px solid var(--color-border);
    display: none;
    overflow-y: auto;
    box-shadow: var(--shadow-lg);
  }

  .nav-menu.is-active {
    display: flex;
  }

  .nav-link {
    font-size: var(--fs-md); /* 18px */
    padding: var(--spacing-3);
    border-bottom: 1px solid var(--color-border-light);
  }

  .nav-link.active::after {
    display: none;
  }

  .mobile-menu-cta {
    margin-top: var(--spacing-4);
    display: block !important;
  }

  .grid-2,
  .grid-3 {
    grid-template-columns: 1fr;
  }

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

  .footer-grid {
    grid-template-columns: 1fr;
    gap: var(--spacing-6);
  }

  .footer-brand-col {
    grid-column: span 1;
  }

  .footer-bottom {
    flex-direction: column;
    gap: var(--spacing-4);
    text-align: center;
  }
}

/* Mobile Devices (<= 480px) */
@media (max-width: 480px) {
  :root {
    --container-padding: 1rem;
    --fs-hero: 1.875rem; /* 30px */
  }

  .grid-4 {
    grid-template-columns: 1fr;
  }

  .btn {
    padding: 10px 18px;
    /* font size remains strictly 14px or 15px */
  }

  .filter-tabs {
    justify-content: flex-start;
    overflow-x: auto;
    padding-bottom: var(--spacing-2);
    flex-wrap: nowrap;
  }

  .filter-tab {
    flex-shrink: 0;
  }
}

/* Small Screen Verification (360px & 390px) */
@media (max-width: 390px) {
  .brand-name {
    font-size: var(--fs-base); /* 16px */
  }

  .brand-subtext {
    font-size: var(--fs-xs); /* 14px */
  }

  .hero-actions {
    flex-direction: column;
    width: 100%;
  }

  .hero-actions .btn {
    width: 100%;
  }
}