/* ==========================================================================
   EpsylonTech — Data & Generative AI Consulting
   Modern, minimal, professional static site
   ========================================================================== */

/* ---------- Design tokens ---------- */
:root {
  --color-bg: #fafafa;
  --color-bg-alt: #f0f4f8;
  --color-surface: #ffffff;
  --color-text: #1a1d23;
  --color-text-muted: #5c6573;
  --color-accent: #0d7377;
  --color-accent-hover: #0a5c5f;
  --color-border: #e2e6eb;
  --color-border-light: #eef0f2;

  --font-sans: "DM Sans", system-ui, -apple-system, sans-serif;
  --font-serif: "DM Serif Display", Georgia, serif;

  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 2rem;
  --space-2xl: 3rem;
  --space-3xl: 4rem;

  --container-max: 72rem;
  --container-padding: 1.25rem;

  --radius: 6px;
  --radius-lg: 10px;

  --transition: 0.2s ease;
}

/* ---------- Reset & base ---------- */
*, *::before, *::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: var(--font-sans);
  font-size: 1rem;
  line-height: 1.6;
  color: var(--color-text);
  background-color: var(--color-bg);
  background-image: 
    radial-gradient(ellipse 80% 50% at 50% -20%, rgba(13, 115, 119, 0.22), transparent),
    radial-gradient(ellipse 60% 40% at 100% 50%, rgba(13, 115, 119, 0.16), transparent);
  background-size: 100% 100%;
  -webkit-font-smoothing: antialiased;
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

a {
  color: var(--color-accent);
  text-decoration: none;
  transition: color var(--transition);
}

a:hover {
  color: var(--color-accent-hover);
}

/* ---------- Utility ---------- */
.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.skip-link {
  position: absolute;
  top: -100%;
  left: var(--space-md);
  padding: var(--space-sm) var(--space-md);
  background: var(--color-text);
  color: var(--color-surface);
  z-index: 100;
  transition: top var(--transition);
}

.skip-link:focus {
  top: var(--space-md);
}

/* ---------- Layout ---------- */
.container {
  max-width: var(--container-max);
  margin: 0 auto;
  padding-left: var(--container-padding);
  padding-right: var(--container-padding);
}

.section {
  padding-top: var(--space-3xl);
  padding-bottom: var(--space-3xl);
}

.section-title {
  font-family: var(--font-serif);
  font-size: clamp(1.75rem, 4vw, 2.25rem);
  font-weight: 400;
  color: var(--color-text);
  margin: 0 0 var(--space-lg);
}

.section-intro {
  max-width: 42rem;
  color: var(--color-text-muted);
  margin: 0 0 var(--space-2xl);
  font-size: 1.0625rem;
}

.lead {
  font-size: 1.125rem;
  line-height: 1.7;
  color: var(--color-text-muted);
  max-width: 52rem;
  margin: 0 auto;
  text-align: center;
}

/* ---------- Header ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--color-border-light);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: var(--space-lg);
  padding-bottom: var(--space-lg);
}

.logo {
  font-weight: 600;
  font-size: 1.25rem;
  color: var(--color-text);
}

.logo:hover {
  color: var(--color-accent);
}

.nav-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  gap: var(--space-xl);
}

.nav-list a {
  color: var(--color-text-muted);
  font-size: 0.9375rem;
  font-weight: 500;
}

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

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  padding: var(--space-sm);
  background: none;
  border: none;
  cursor: pointer;
}

.nav-toggle span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--color-text);
  transition: transform 0.2s ease, opacity 0.2s ease;
}

/* ---------- Hero ---------- */
.hero {
  position: relative;
  padding-top: var(--space-3xl);
  padding-bottom: var(--space-3xl);
  min-height: 60vh;
  display: flex;
  align-items: center;
}

.hero-bg {
  position: absolute;
  inset: 0;
  background: 
    linear-gradient(135deg, #f0f9ff 0%, #fafafa 45%, #e8f4f6 70%, #f0f4f8 100%);
  background-size: 200% 200%;
  z-index: -1;
  overflow: hidden;
}

.hero-bg::before {
  content: "";
  position: absolute;
  inset: 0;
  /* stronger, slightly denser grid overlay for better contrast */
  background-image: 
    linear-gradient(rgba(13, 115, 119, 0.075) 1px, transparent 1px),
    linear-gradient(90deg, rgba(13, 115, 119, 0.075) 1px, transparent 1px);
  background-size: 2.5rem 2.5rem;
  pointer-events: none;
}

@media (prefers-reduced-motion: no-preference) {
  .hero-bg {
    animation: hero-gradient 3s ease-in-out infinite;
  }
}

@keyframes hero-gradient {
  0%, 100% { background-position: 0% 50%; }
  50% { background-position: 100% 50%; }
}

.hero-blob {
  position: absolute;
  border-radius: 50%;
  filter: blur(70px);
  opacity: 0.5;
  pointer-events: none;
}

.hero-blob-1 {
  width: min(70vw, 32rem);
  height: min(70vw, 32rem);
  background: radial-gradient(circle, rgba(13, 115, 119, 0.55) 0%, transparent 70%);
  top: -15%;
  right: -10%;
}

.hero-blob-2 {
  width: min(50vw, 24rem);
  height: min(50vw, 24rem);
  background: radial-gradient(circle, rgba(13, 115, 119, 0.38) 0%, transparent 70%);
  bottom: -20%;
  left: -5%;
}

.hero-blob-3 {
  width: min(40vw, 18rem);
  height: min(40vw, 18rem);
  background: radial-gradient(circle, rgba(13, 115, 119, 0.32) 0%, transparent 70%);
  top: 40%;
  left: 30%;
}

@media (prefers-reduced-motion: no-preference) {
  .hero-blob-1 { animation: blob-float 16s ease-in-out infinite; }
  .hero-blob-2 { animation: blob-float 18s ease-in-out infinite 3s; }
  .hero-blob-3 { animation: blob-float 14s ease-in-out infinite 1s; }
}

@keyframes blob-float {
  0%, 100% { transform: translate(0, 0) scale(1); }
  33% { transform: translate(5%, -8%) scale(1.05); }
  66% { transform: translate(-5%, 5%) scale(0.98); }
}

.hero-inner {
  width: 100%;
}

.hero-title {
  font-family: var(--font-serif);
  font-size: clamp(2rem, 5vw, 3.25rem);
  font-weight: 400;
  line-height: 1.2;
  color: var(--color-text);
  margin: 0 0 var(--space-lg);
  max-width: 28ch;
}

.hero-tagline {
  font-size: 1.125rem;
  color: var(--color-text-muted);
  max-width: 42rem;
  margin: 0 0 var(--space-xl);
}

.hero-cta {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-md);
}

/* ---------- Buttons ---------- */
.btn {
  display: inline-block;
  padding: 0.75rem 1.5rem;
  font-family: var(--font-sans);
  font-size: 0.9375rem;
  font-weight: 600;
  border-radius: var(--radius);
  border: none;
  cursor: pointer;
  transition: background-color var(--transition), color var(--transition);
}

.btn-primary {
  background: var(--color-accent);
  color: #fff;
}

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

.btn-secondary {
  background: transparent;
  color: var(--color-text);
  border: 1px solid var(--color-border);
}

.btn-secondary:hover {
  background: var(--color-border-light);
  border-color: var(--color-text-muted);
}

/* ---------- Intro ---------- */
.intro {
  padding-top: var(--space-2xl);
  padding-bottom: var(--space-2xl);
}

/* ---------- Dynamic section backgrounds ---------- */
.section-dynamic {
  position: relative;
}

.section-dynamic .section-bg {
  position: absolute;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  background-size: 200% 200%;
}

.section-dynamic .section-bg::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image: 
    linear-gradient(rgba(13, 115, 119, 0.04) 1px, transparent 1px),
    linear-gradient(90deg, rgba(13, 115, 119, 0.04) 1px, transparent 1px);
  background-size: 2.5rem 2.5rem;
  pointer-events: none;
}

.section-dynamic .container {
  position: relative;
  z-index: 1;
}

.services .section-bg,
.about .section-bg,
.intro .section-bg,
.who-for .section-bg,
.contact .section-bg {
  background: linear-gradient(115deg, #ffffff 0%, #f8fbfd 25%, #f0f8fa 50%, #f8fbfd 75%, #ffffff 100%);
}

@media (prefers-reduced-motion: no-preference) {
  .section-dynamic .section-bg {
    animation: section-gradient 3s ease-in-out infinite;
  }
}

@keyframes section-gradient {
  0%, 100% { background-position: 0% 50%; }
  50% { background-position: 100% 50%; }
}

/* ---------- Services ---------- */

.services-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-xl);
  margin-top: var(--space-xl);
}

@media (min-width: 48rem) {
  .services-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

.service-card {
  padding: var(--space-xl);
  background: var(--color-bg);
  border-radius: var(--radius-lg);
  border: 1px solid var(--color-border-light);
  transition: box-shadow var(--transition), border-color var(--transition);
}

.service-card:hover {
  border-color: var(--color-border);
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.06);
}

.service-icon {
  color: var(--color-accent);
  margin-bottom: var(--space-md);
}

.service-title {
  font-size: 1.125rem;
  font-weight: 600;
  margin: 0 0 var(--space-sm);
  color: var(--color-text);
}

.service-desc {
  color: var(--color-text-muted);
  font-size: 0.9375rem;
  margin: 0 0 var(--space-md);
}

.service-bullets {
  margin: 0;
  padding-left: 1.25rem;
  font-size: 0.875rem;
  color: var(--color-text-muted);
  line-height: 1.7;
}

.service-bullets li {
  margin-bottom: var(--space-xs);
}

/* ---------- About ---------- */

.about-grid {
  display: grid;
  gap: var(--space-2xl);
}

@media (min-width: 56rem) {
  .about-grid {
    grid-template-columns: 1fr 1fr;
    align-items: start;
    gap: var(--space-3xl);
  }
}

.about-lead {
  font-size: 1.0625rem;
  color: var(--color-text-muted);
  margin: 0 0 var(--space-lg);
}

.about-content p {
  margin: 0 0 var(--space-md);
  color: var(--color-text);
}

.about-image-wrap {
  border-radius: var(--radius-lg);
  overflow: hidden;
  background: var(--color-border-light);
}

.about-image-wrap img {
  width: 100%;
  object-fit: cover;
}

/* ---------- Who We Serve ---------- */
.who-for .section-intro {
  margin-bottom: var(--space-xl);
}

.audience-list {
  list-style: none;
  margin: 0;
  padding: 0;
}

.audience-item {
  display: grid;
  gap: var(--space-sm);
  padding: var(--space-lg) 0;
  border-bottom: 1px solid var(--color-border-light);
}

.audience-item:last-child {
  border-bottom: none;
}

.audience-label {
  font-weight: 600;
  color: var(--color-text);
}

.audience-desc {
  color: var(--color-text-muted);
  font-size: 0.9375rem;
}

/* ---------- Contact ---------- */

.contact-options {
  display: grid;
  gap: var(--space-2xl);
}

@media (min-width: 40rem) {
  .contact-options {
    grid-template-columns: auto 1fr;
    align-items: start;
    gap: var(--space-3xl);
  }
}

.contact-email h3 {
  font-size: 0.875rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--color-text-muted);
  margin: 0 0 var(--space-sm);
}

.contact-email a {
  font-size: 1.125rem;
}

.contact-form {
  max-width: 28rem;
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
}

.contact-form label {
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--color-text);
}

.contact-form input,
.contact-form textarea {
  font-family: var(--font-sans);
  font-size: 1rem;
  padding: 0.625rem 0.75rem;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background: var(--color-surface);
  transition: border-color var(--transition);
}

.contact-form input:focus,
.contact-form textarea:focus {
  outline: none;
  border-color: var(--color-accent);
}

.contact-form textarea {
  resize: vertical;
  min-height: 120px;
}

/* ---------- Footer ---------- */
.site-footer {
  padding: var(--space-2xl) 0;
  background: var(--color-text);
  color: var(--color-bg);
  text-align: center;
}

.footer-brand {
  font-weight: 600;
  font-size: 1rem;
  margin: 0 0 var(--space-xs);
}

.footer-tagline {
  font-size: 0.875rem;
  color: rgba(255, 255, 255, 0.75);
  margin: 0 0 var(--space-md);
}

.footer-copy {
  font-size: 0.8125rem;
  color: rgba(255, 255, 255, 0.6);
  margin: 0;
}

.site-footer a {
  color: rgba(255, 255, 255, 0.9);
}

/* Footer newsletter */
.footer-newsletter {
  display: inline-flex;
  gap: var(--space-sm);
  margin: var(--space-md) 0 var(--space-sm);
  align-items: center;
}
.footer-newsletter input {
  padding: 0.5rem 0.75rem;
  border-radius: var(--radius);
  border: 1px solid rgba(255,255,255,0.12);
  background: rgba(255,255,255,0.06);
  color: #fff;
  font-size: 0.95rem;
}
.footer-newsletter input::placeholder { color: rgba(255,255,255,0.7); }
.footer-newsletter .btn { padding: 0.5rem 0.9rem; font-size: 0.95rem; }

/* ---------- Mobile nav ---------- */
@media (max-width: 47.9375rem) {
  .nav {
    position: fixed;
    top: 0;
    right: 0;
    width:  min(85vw, 20rem);
    height: 100vh;
    background: var(--color-surface);
    padding: var(--space-2xl);
    transform: translateX(100%);
    transition: transform var(--transition);
    box-shadow: -4px 0 20px rgba(0, 0, 0, 0.08);
  }

  .nav.is-open {
    transform: translateX(0);
  }

  .nav-list {
    flex-direction: column;
    gap: var(--space-lg);
    padding-top: 3rem;
  }

  .nav-toggle {
    display: flex;
  }

  .nav-toggle[aria-expanded="true"] span:first-child {
    transform: rotate(45deg) translate(5px, 5px);
  }

  .nav-toggle[aria-expanded="true"] span:nth-child(2) {
    opacity: 0;
  }

  .nav-toggle[aria-expanded="true"] span:last-child {
    transform: rotate(-45deg) translate(5px, -5px);
  }
}

/* ---------- Lightweight scroll-in (optional) ---------- */
@keyframes fade-in-up {
  from {
    opacity: 0;
    transform: translateY(12px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.hero-title,
.hero-tagline,
.hero-cta {
  animation: fade-in-up 0.6s ease-out;
}

.hero-tagline { animation-delay: 0.08s; animation-fill-mode: both; }
.hero-cta     { animation-delay: 0.16s; animation-fill-mode: both; }