/* ==========================================================================
   Responsive Design — Mobile First
   ========================================================================== */

/* Small devices (375px+) */
@media (max-width: 767px) {
  :root {
    --section-spacing: 3rem;
  }

  h1 { font-size: var(--text-3xl); }
  h2 { font-size: var(--text-2xl); }
  h3 { font-size: var(--text-xl); }

  .container {
    padding: 0 var(--space-4);
  }

  /* Navbar */
  .navbar__links {
    display: none;
  }

  .navbar__hamburger {
    display: flex;
  }

  .navbar__actions {
    gap: var(--space-1);
  }

  .navbar__actions .navbar__social-link {
    display: none;
  }

  /* Hero */
  .hero {
    min-height: auto;
    padding: calc(72px + var(--space-8)) 0 var(--space-8);
  }

  .hero__inner {
    grid-template-columns: 1fr;
    gap: var(--space-8);
    text-align: center;
  }

  .hero__title {
    font-size: var(--text-3xl);
  }

  .hero__description {
    margin: 0 auto var(--space-6);
  }

  .hero__cta {
    justify-content: center;
  }

  .hero__visual {
    order: -1;
  }

  .hero__image-wrapper {
    width: 200px;
    height: 200px;
  }

  .hero__stats {
    gap: var(--space-4);
  }

  .hero__stat-value {
    font-size: var(--text-2xl);
  }

  /* Grids */
  .grid--2,
  .grid--3,
  .grid--4 {
    grid-template-columns: 1fr;
  }

  .projects-grid,
  .blog-grid {
    grid-template-columns: 1fr;
    gap: var(--space-6);
  }

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

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

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

  /* Footer */
  .footer__inner {
    grid-template-columns: 1fr;
    gap: var(--space-8);
  }

  .footer__bottom {
    flex-direction: column;
    gap: var(--space-3);
    text-align: center;
  }

  /* Contact */
  .contact-grid {
    grid-template-columns: 1fr;
    gap: var(--space-8);
  }

  /* Page Header */
  .page-header {
    padding: calc(72px + var(--space-8)) 0 var(--space-8);
  }

  .page-header__title {
    font-size: var(--text-3xl);
  }

  /* Timeline */
  .timeline {
    padding-left: var(--space-6);
  }

  .timeline__dot {
    left: calc(-1 * var(--space-6) - 5px);
  }

  .timeline__title {
    font-size: var(--text-lg);
  }

  /* Section */
  .section__title {
    font-size: var(--text-2xl);
  }

  /* Cert Grid */
  .cert-grid {
    grid-template-columns: 1fr;
  }

  /* CTA */
  .cta-section__title {
    font-size: var(--text-2xl);
  }

  /* Filters */
  .filters {
    overflow-x: auto;
    flex-wrap: nowrap;
    -webkit-overflow-scrolling: touch;
    padding-bottom: var(--space-2);
  }

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

  /* Back to top */
  .back-to-top {
    right: var(--space-4);
    bottom: var(--space-4);
    width: 40px;
    height: 40px;
  }
}

/* Tablets (768px+) */
@media (min-width: 768px) and (max-width: 1023px) {
  .hero__inner {
    grid-template-columns: 1fr;
    text-align: center;
  }

  .hero__title {
    font-size: var(--text-4xl);
  }

  .hero__description {
    margin: 0 auto var(--space-8);
  }

  .hero__cta {
    justify-content: center;
  }

  .hero__visual {
    order: -1;
  }

  .hero__image-wrapper {
    width: 280px;
    height: 280px;
  }

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

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

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

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

  .navbar__links {
    display: none;
  }

  .navbar__hamburger {
    display: flex;
  }
}

/* Desktop (1024px+) */
@media (min-width: 1024px) {
  .hero__title {
    font-size: var(--text-5xl);
  }

  .navbar__hamburger {
    display: none;
  }

  .navbar__links {
    display: flex;
  }
}

/* Large Desktop (1280px+) */
@media (min-width: 1280px) {
  .hero__title {
    font-size: 3.5rem;
  }

  .projects-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

/* Extra Large (1440px+) */
@media (min-width: 1440px) {
  .container {
    padding: 0 var(--space-8);
  }
}