/* ==========================================================================
   YANTRA SYSTEMS — Main Stylesheet
   ========================================================================== */

/* --- DESIGN TOKENS (DARK — default) --- */
:root {
  /* Dark palette */
  --bg: #1a1f1a;
  --bg-elevated: #222822;
  --bg-card: #2a302a;
  --border: #3a423a;
  --border-light: #4a524a;
  --text-primary: #e8e4de;
  --text-secondary: #a8a49e;
  --text-muted: #78756f;
  --accent: #c9a96e;
  --accent-dim: #9a7d4e;
  --green-dot: #6abf6a;

  /* Shared tokens */
  --mono: 'DM Mono', 'Menlo', monospace;
  --sans: 'DM Sans', 'Helvetica Neue', Arial, sans-serif;
  --serif: 'Source Serif 4', 'Georgia', serif;
  --max-w: 1400px;
  --page-pad: clamp(1.25rem, 4vw, 3rem);
  --radius: 8px;
  --transition: 0.3s ease;
}

/* --- LIGHT PALETTE --- */
[data-theme="light"] {
  --bg: #f4f1eb;
  --bg-elevated: #eae7e0;
  --bg-card: #dfdcd5;
  --border: #ccc8c0;
  --border-light: #b8b4ac;
  --text-primary: #1a1f1a;
  --text-secondary: #4a4840;
  --text-muted: #7a776f;
  --accent: #8a6d30;
  --accent-dim: #6a5425;
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* Scale up for large monitors — 1440p and above */
@media (min-width: 1440px) {
  html { font-size: 18px; }
}

@media (min-width: 1920px) {
  html { font-size: 19px; }
}

@media (min-width: 2560px) {
  html { font-size: 20px; }
}

body {
  background: var(--bg);
  color: var(--text-primary);
  font-family: var(--sans);
  font-weight: 400;
  line-height: 1.7;
  overflow-x: hidden;
  transition: background var(--transition), color var(--transition);
}

img { max-width: 100%; display: block; }
a { color: inherit; }

/* --- NOISE OVERLAY --- */
body::before {
  content: '';
  position: fixed;
  inset: 0;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 256 256' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.85' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)' opacity='0.03'/%3E%3C/svg%3E");
  pointer-events: none;
  z-index: 9999;
}

/* --- DOT GRID BACKGROUND --- */
body::after {
  content: '';
  position: fixed;
  inset: 0;
  background-image: radial-gradient(circle, var(--text-muted) 1px, transparent 1px);
  background-size: 30px 30px;
  opacity: 0.35;
  pointer-events: none;
  z-index: -1;
}

/* ==========================================================================
   NAVIGATION
   ========================================================================== */
.site-nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1.25rem var(--page-pad);
  max-width: var(--max-w);
  margin: 0 auto;
  position: relative;
  z-index: 100;
}

.site-logo {
  font-family: var(--mono);
  font-size: 0.8rem;
  font-weight: 500;
  letter-spacing: 0.15em;
  color: var(--text-primary);
  text-decoration: none;
}

.nav-right {
  display: flex;
  align-items: center;
  gap: 2rem;
}

.nav-links {
  display: flex;
  gap: 2rem;
  list-style: none;
  align-items: center;
}

.nav-links a {
  font-family: var(--mono);
  font-size: 0.8rem;
  color: var(--text-secondary);
  text-decoration: none;
  letter-spacing: 0.03em;
  transition: color var(--transition);
}

.nav-links a:hover { color: var(--text-primary); }

/* --- THEME SWITCHER --- */
.theme-switcher {
  position: relative;
}

.theme-switcher__btn {
  font-family: var(--mono);
  font-size: 0.7rem;
  color: var(--text-muted);
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 0.4rem 0.75rem;
  min-width: 5.5rem;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 0.4rem;
  transition: border-color var(--transition), color var(--transition);
  letter-spacing: 0.03em;
}

.theme-switcher__btn:hover {
  border-color: var(--border-light);
  color: var(--text-secondary);
}

.theme-switcher__icon {
  width: 14px;
  height: 14px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.theme-switcher__dropdown {
  position: absolute;
  top: calc(100% + 6px);
  right: 0;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 0.35rem 0;
  min-width: 130px;
  opacity: 0;
  visibility: hidden;
  transform: translateY(-4px);
  transition: all 0.2s ease;
  z-index: 200;
}

.theme-switcher__dropdown.is-open {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.theme-switcher__option {
  font-family: var(--mono);
  font-size: 0.7rem;
  color: var(--text-secondary);
  padding: 0.5rem 0.85rem;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  transition: background 0.15s ease, color 0.15s ease;
  letter-spacing: 0.03em;
  background: none;
  border: none;
  width: 100%;
  text-align: left;
}

.theme-switcher__option .theme-switcher__icon {
  display: inline-block;
  width: 1.1em;
  text-align: center;
  flex-shrink: 0;
}

.theme-switcher__option:hover {
  background: var(--bg-card);
  color: var(--text-primary);
}

.theme-switcher__option.is-active {
  color: var(--accent);
}

/* --- MOBILE NAV TOGGLE --- */
.nav-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0.5rem;
  color: var(--text-primary);
}

.nav-toggle svg {
  width: 22px;
  height: 22px;
  stroke: currentColor;
  fill: none;
  stroke-width: 2;
}

/* ==========================================================================
   SHARED COMPONENTS
   ========================================================================== */
.section-wrap {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 5rem var(--page-pad);
  position: relative;
}

.divider {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 0 var(--page-pad);
  position: relative;
}

.divider hr {
  border: none;
  border-top: 1px solid var(--border);
}

.section-label {
  font-family: var(--mono);
  font-size: 0.65rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--text-muted);
  margin-bottom: 0.75rem;
}

.btn {
  font-family: var(--mono);
  font-size: 0.8rem;
  padding: 0.85rem 1.75rem;
  border: 1px solid var(--border);
  background: transparent;
  color: var(--text-primary);
  text-decoration: none;
  letter-spacing: 0.04em;
  cursor: pointer;
  transition: all var(--transition);
  display: inline-block;
  border-radius: 4px;
}

.btn:hover {
  border-color: var(--accent-dim);
  color: var(--accent);
}

.btn--primary {
  background: var(--accent);
  border-color: var(--accent);
  color: var(--bg);
}

.btn--primary:hover {
  background: var(--accent-dim);
  border-color: var(--accent-dim);
  color: var(--bg);
}

/* ==========================================================================
   HERO
   ========================================================================== */
.hero {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 6rem var(--page-pad) 5rem;
  min-height: 75vh;
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
}

.hero__content {
  position: relative;
  max-width: 640px;
  text-align: center;
}

.hero__title {
  font-family: var(--serif);
  font-size: clamp(2.6rem, 5.5vw, 4rem);
  font-weight: 300;
  line-height: 1.12;
  margin-bottom: 1.75rem;
}

.hero__title em {
  font-style: italic;
  color: var(--accent);
}

.hero__tagline {
  font-size: 1.05rem;
  color: var(--text-secondary);
  line-height: 1.75;
  margin-bottom: 1.5rem;
}

.hero__status {
  font-family: var(--mono);
  font-size: 0.8rem;
  color: var(--text-secondary);
  letter-spacing: 0.02em;
  margin-bottom: 2rem;
}

.hero__actions {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
  justify-content: center;
}

/* Hero info cards — kept for portfolio or reuse */
.hero__cards {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
  padding-top: 0.5rem;
}

.info-card {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem;
  background: var(--bg-elevated);
  transition: border-color var(--transition);
}

.info-card:hover { border-color: var(--border-light); }

.info-card__label {
  font-family: var(--mono);
  font-size: 0.65rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--text-muted);
  margin-bottom: 0.5rem;
}

.info-card__title {
  font-family: var(--serif);
  font-size: 1.15rem;
  font-weight: 600;
  margin-bottom: 0.35rem;
}

.info-card__desc {
  font-size: 0.8rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

.status-dot {
  display: inline-block;
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--green-dot);
  margin-right: 0.4rem;
  animation: pulse-dot 2.5s ease-in-out infinite;
  vertical-align: middle;
}

@keyframes pulse-dot {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.4; }
}

/* ==========================================================================
   PROBLEM SECTION
   ========================================================================== */
.problem {
  display: grid;
  grid-template-columns: 1fr 1.2fr;
  gap: 4rem;
  align-items: start;
}

.problem__headline {
  font-family: var(--serif);
  font-size: clamp(1.8rem, 3.5vw, 2.6rem);
  font-weight: 300;
  line-height: 1.2;
}

.problem__headline em {
  font-style: italic;
  color: var(--accent);
}

.problem__body p {
  font-size: 0.95rem;
  color: var(--text-secondary);
  line-height: 1.8;
  margin-bottom: 1.25rem;
}

.problem__body p:last-child { margin-bottom: 0; }

/* ==========================================================================
   SERVICES
   ========================================================================== */
.services__header {
  margin-bottom: 3rem;
}

.services__header h2 {
  font-family: var(--serif);
  font-size: clamp(1.6rem, 3vw, 2.2rem);
  font-weight: 300;
}

.service-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1.25rem;
}

.service-item {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 2rem 1.75rem;
  background: var(--bg-elevated);
  transition: border-color var(--transition);
}

.service-item:hover {
  border-color: var(--border-light);
}

.service-item__num {
  font-family: var(--mono);
  font-size: 0.65rem;
  color: var(--text-muted);
  letter-spacing: 0.1em;
  margin-bottom: 1.25rem;
  display: block;
}

.service-item h3 {
  font-family: var(--serif);
  font-size: 1.15rem;
  font-weight: 600;
  margin-bottom: 0.75rem;
  line-height: 1.35;
}

.service-item p {
  font-size: 0.85rem;
  color: var(--text-secondary);
  line-height: 1.7;
}

/* ==========================================================================
   CASE STUDY TEASER
   ========================================================================== */
.case-study__card {
  border: 1px solid var(--border);
  border-radius: 10px;
  background: var(--bg-elevated);
  padding: 3rem;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 3rem;
  align-items: center;
  transition: border-color var(--transition);
}

.case-study__card:hover { border-color: var(--border-light); }

.case-study__label {
  font-family: var(--mono);
  font-size: 0.65rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--accent-dim);
  margin-bottom: 1rem;
}

.case-study__title {
  font-family: var(--serif);
  font-size: clamp(1.4rem, 2.5vw, 1.85rem);
  font-weight: 400;
  margin-bottom: 1rem;
  line-height: 1.3;
}

.case-study__desc {
  font-size: 0.9rem;
  color: var(--text-secondary);
  line-height: 1.75;
  margin-bottom: 1.5rem;
}

.case-study__link {
  font-family: var(--mono);
  font-size: 0.8rem;
  color: var(--accent);
  text-decoration: none;
  letter-spacing: 0.03em;
  transition: color var(--transition);
}

.case-study__link:hover { color: var(--text-primary); }
.case-study__link::after { content: ' →'; }

.case-study__details {
  display: flex;
  flex-direction: column;
  gap: 0;
}

.detail-row {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  padding: 0.85rem 0;
  border-bottom: 1px solid var(--border);
}

.detail-row:last-child { border-bottom: none; }

.detail-row__key {
  font-family: var(--mono);
  font-size: 0.7rem;
  color: var(--text-muted);
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.detail-row__val {
  font-size: 0.85rem;
  text-align: right;
}

/* ==========================================================================
   PROCESS / HOW IT WORKS
   ========================================================================== */
.process__header {
  margin-bottom: 3rem;
}

.process__header h2 {
  font-family: var(--serif);
  font-size: clamp(1.6rem, 3vw, 2.2rem);
  font-weight: 300;
}

.process-steps {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1.25rem;
}

.step {
  padding: 1.75rem 1.5rem;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--bg-elevated);
}

.step__num {
  font-family: var(--serif);
  font-size: 1.6rem;
  font-weight: 600;
  color: var(--accent);
  margin-bottom: 1rem;
  display: block;
  opacity: 0.5;
}

.step h4 {
  font-family: var(--mono);
  font-size: 0.85rem;
  font-weight: 500;
  margin-bottom: 0.5rem;
}

.step p {
  font-size: 0.8rem;
  color: var(--text-secondary);
  line-height: 1.7;
}

/* ==========================================================================
   CTA
   ========================================================================== */
.cta {
  text-align: center;
  padding: 6rem var(--page-pad);
}

.cta h2 {
  font-family: var(--serif);
  font-size: clamp(1.8rem, 3.5vw, 2.8rem);
  font-weight: 300;
  margin-bottom: 1rem;
  line-height: 1.2;
}

.cta h2 em {
  font-style: italic;
  color: var(--accent);
}

.cta p {
  font-size: 0.9rem;
  color: var(--text-secondary);
  max-width: 500px;
  margin: 0 auto 2.5rem;
  line-height: 1.7;
}

.cta__actions {
  display: flex;
  gap: 1rem;
  justify-content: center;
  flex-wrap: wrap;
}

/* ==========================================================================
   FOOTER
   ========================================================================== */
.site-footer {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 2rem var(--page-pad);
  border-top: 1px solid var(--border);
  display: flex;
  justify-content: space-between;
  align-items: center;
  position: relative;
}

.site-footer span,
.site-footer a {
  font-family: var(--mono);
  font-size: 0.7rem;
  color: var(--text-muted);
  letter-spacing: 0.03em;
}

.site-footer a {
  text-decoration: none;
  transition: color var(--transition);
}

.site-footer a:hover { color: var(--text-secondary); }

.footer-links {
  display: flex;
  gap: 1.5rem;
}

/* ==========================================================================
   SCROLL TO TOP
   ========================================================================== */
.scroll-top {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  color: var(--text-secondary);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  visibility: hidden;
  transform: translateY(8px);
  transition: all 0.35s ease;
  z-index: 500;
}

.scroll-top.is-visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.scroll-top:hover {
  border-color: var(--accent-dim);
  color: var(--accent);
  background: var(--bg-card);
}

.scroll-top svg {
  width: 16px;
  height: 16px;
  stroke: currentColor;
  fill: none;
  stroke-width: 2.5;
}

/* ==========================================================================
   ENTRANCE ANIMATIONS
   ========================================================================== */
/* Hero — immediate on load */
.fade-up {
  opacity: 0;
  transform: translateY(20px);
  animation: fadeUp 0.7s ease forwards;
}

@keyframes fadeUp {
  to { opacity: 1; transform: translateY(0); }
}

.delay-1 { animation-delay: 0.1s; }
.delay-2 { animation-delay: 0.2s; }
.delay-3 { animation-delay: 0.3s; }
.delay-4 { animation-delay: 0.4s; }
.delay-5 { animation-delay: 0.5s; }

/* Scroll-triggered — activated by IntersectionObserver */
.reveal {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.reveal.is-visible {
  opacity: 1;
  transform: translateY(0);
}

/* ==========================================================================
   PORTFOLIO GRID
   ========================================================================== */
.portfolio-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.5rem;
}

.project-card {
  display: block;
  text-decoration: none;
  color: inherit;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--bg-elevated);
  padding: 2.5rem;
  transition: border-color var(--transition);
}

.project-card:hover {
  border-color: var(--border-light);
}

.project-card__header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 1.25rem;
}

.project-card__label {
  font-family: var(--mono);
  font-size: 0.65rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--accent-dim);
}

.project-card__arrow {
  font-size: 1.1rem;
  color: var(--text-muted);
  transition: color var(--transition), transform var(--transition);
}

.project-card:hover .project-card__arrow {
  color: var(--accent);
  transform: translateX(4px);
}

.project-card__title {
  font-family: var(--serif);
  font-size: clamp(1.3rem, 2.5vw, 1.7rem);
  font-weight: 400;
  margin-bottom: 0.75rem;
  line-height: 1.3;
}

.project-card__desc {
  font-size: 0.9rem;
  color: var(--text-secondary);
  line-height: 1.75;
  margin-bottom: 1.5rem;
  max-width: 640px;
}

.project-card__stack {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  margin-bottom: 1.25rem;
}

.stack-pill {
  font-family: var(--mono);
  font-size: 0.7rem;
  padding: 0.25rem 0.65rem;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 3px;
  color: var(--text-secondary);
  letter-spacing: 0.03em;
}

.project-card__meta {
  font-family: var(--mono);
  display: flex;
  gap: 1.5rem;
  font-size: 0.7rem;
  color: var(--text-muted);
  letter-spacing: 0.03em;
}

/* ==========================================================================
   CASE STUDY PAGE
   ========================================================================== */
.cs-back-link {
  display: inline-block;
  font-family: var(--mono);
  font-size: 0.75rem;
  color: var(--text-secondary);
  text-decoration: none;
  letter-spacing: 0.03em;
  margin-bottom: 2.5rem;
  padding: 0.5rem 1rem;
  border: 1px solid var(--border);
  border-radius: 4px;
  background: var(--bg-elevated);
  transition: border-color var(--transition), color var(--transition);
}

.cs-back-link:hover {
  color: var(--text-primary);
  border-color: var(--border-light);
}

/* Case study hero */
.cs-hero {
  padding-top: 3rem;
  padding-bottom: 4rem;
  display: flex;
  flex-direction: column;
  align-items: center;
}

.cs-hero .cs-back-link {
  align-self: flex-start;
  margin-bottom: 2.5rem;
}

.cs-header {
  margin-bottom: 2.5rem;
  text-align: center;
}

.cs-hero-title {
  font-family: var(--serif);
  font-size: clamp(2.4rem, 4.5vw, 3.4rem);
  font-weight: 300;
  line-height: 1.15;
  margin-bottom: 1.25rem;
}

.cs-hero-subtitle {
  font-size: 1rem;
  color: var(--text-secondary);
  line-height: 1.75;
  max-width: 600px;
  margin: 0 auto;
}

.cs-meta-row {
  display: flex;
  flex-wrap: wrap;
  gap: 2.5rem;
  justify-content: center;
}

.cs-meta-item {
  display: flex;
  flex-direction: column;
  gap: 0.2rem;
}

.cs-meta-key {
  font-family: var(--mono);
  font-size: 0.65rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-muted);
}

.cs-meta-val {
  font-size: 0.9rem;
  color: var(--text-primary);
}

/* Case study sections — centered single column */
.cs-section {
  display: flex;
  justify-content: center;
}

.cs-section .section-wrap {
  max-width: 800px;
}

.cs-section-grid {
  max-width: 800px;
  margin: 0 auto;
}

.cs-section-num {
  text-align: center;
  margin-bottom: 1rem;
}

.cs-section-body {
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 2.5rem;
}

.cs-section-title {
  font-family: var(--serif);
  font-size: clamp(1.3rem, 2.5vw, 1.8rem);
  font-weight: 400;
  margin-bottom: 1.25rem;
  line-height: 1.3;
  text-align: center;
}

.cs-section-body p {
  font-size: 0.9rem;
  color: var(--text-secondary);
  line-height: 1.8;
  margin-bottom: 1.25rem;
}

.cs-section-body p:last-child {
  margin-bottom: 0;
}

.cs-section-body code {
  font-family: var(--mono);
  font-size: 0.8rem;
  background: var(--bg-card);
  padding: 0.15rem 0.4rem;
  border-radius: 3px;
  border: 1px solid var(--border);
}

/* Challenge cards */
.cs-challenges {
  display: grid;
  gap: 1.25rem;
}

.cs-challenge-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-left: 3px solid var(--accent-dim);
  border-radius: var(--radius);
  padding: 1.5rem 1.75rem;
}

.cs-challenge-card h3 {
  font-family: var(--mono);
  font-size: 0.85rem;
  font-weight: 500;
  margin-bottom: 0.65rem;
  color: var(--text-primary);
}

.cs-challenge-card p {
  font-size: 0.85rem;
  color: var(--text-secondary);
  line-height: 1.75;
  margin: 0;
}

/* Stack pills on case study page */
.cs-stack-pills {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  justify-content: center;
}

/* Outcome box */
.cs-outcome-box {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 2rem;
}

.cs-outcome-box p {
  font-size: 0.9rem;
  color: var(--text-secondary);
  line-height: 1.8;
  margin-bottom: 1rem;
}

.cs-outcome-box p:last-of-type {
  margin-bottom: 0;
}

.cs-live-link {
  display: inline-block;
  font-family: var(--mono);
  margin-top: 1.5rem;
  font-size: 0.8rem;
  color: var(--accent);
  text-decoration: none;
  letter-spacing: 0.03em;
  transition: color var(--transition);
}

.cs-live-link:hover {
  color: var(--text-primary);
}

/* ==========================================================================
   RESPONSIVE
   ========================================================================== */
@media (max-width: 900px) {
  .hero {
    padding-top: 3rem;
    padding-bottom: 3rem;
    min-height: auto;
  }

  .problem {
    grid-template-columns: 1fr;
    gap: 2rem;
  }

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

  .case-study__card {
    grid-template-columns: 1fr;
    gap: 2rem;
    padding: 2rem;
  }

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

  .cs-section-grid {
    gap: 1rem;
  }

  .cs-section-body {
    padding: 1.75rem;
  }

  .cs-meta-row {
    gap: 1.5rem;
  }
}

@media (max-width: 640px) {
  .nav-links { display: none; }
  .nav-links.is-open {
    display: flex;
    flex-direction: column;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: var(--bg-elevated);
    border-bottom: 1px solid var(--border);
    padding: 1.25rem var(--page-pad);
    gap: 1rem;
  }
  .nav-toggle { display: block; }

  .hero__cards { grid-template-columns: 1fr; }
  .process-steps { grid-template-columns: 1fr; }
  .cta { padding: 4rem var(--page-pad); }

  .scroll-top {
    bottom: 1.25rem;
    right: 1.25rem;
  }

  .project-card {
    padding: 1.75rem;
  }

  .cs-meta-row {
    flex-direction: column;
    gap: 1rem;
  }

  .cs-challenge-card {
    padding: 1.25rem 1.5rem;
  }

  .cs-outcome-box {
    padding: 1.75rem;
  }
}