/* ============================================================
   CSS VARIABLES
   ============================================================ */

:root {
  --bg: #080B12;
  --surface: #0D1120;
  --surface-2: #131B2E;
  --border: #1A2639;
  --border-hover: #2A3D5C;

  --primary: #6366F1;
  --primary-light: #818CF8;
  --primary-glow: rgba(99, 102, 241, 0.12);
  --primary-border: rgba(99, 102, 241, 0.25);

  --accent-green: #34D399;
  --accent-cyan: #22D3EE;

  --text: #F1F5F9;
  --text-muted: #94A3B8;
  --text-subtle: #475569;

  --nav-height: 64px;
  --section-gap: 96px;
  --card-radius: 14px;

  --font-heading: 'Syne', sans-serif;
  --font-body: 'Inter', sans-serif;

  --transition-fast: 150ms ease;
  --transition-base: 260ms ease;

  --shadow-card: 0 4px 24px rgba(0, 0, 0, 0.35);
  --shadow-card-hover: 0 20px 56px rgba(0, 0, 0, 0.55);
  --shadow-primary: 0 8px 32px rgba(99, 102, 241, 0.25);
}

/* ============================================================
   RESET & BASE
   ============================================================ */

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-body);
  background: var(--bg);
  color: var(--text);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

a {
  color: inherit;
  text-decoration: none;
}

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

ul {
  list-style: none;
}

/* ============================================================
   TYPOGRAPHY
   ============================================================ */

h1, h2, h3, h4 {
  font-family: var(--font-heading);
  line-height: 1.1;
  letter-spacing: -0.025em;
  color: var(--text);
}

h1 { font-size: clamp(2.6rem, 6vw, 5rem); font-weight: 800; }
h2 { font-size: clamp(1.8rem, 4vw, 2.8rem); font-weight: 700; }
h3 { font-size: 1.2rem; font-weight: 600; }

p { color: var(--text-muted); }

.text-gradient {
  background: linear-gradient(130deg, var(--primary-light) 0%, var(--accent-cyan) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

/* ============================================================
   LAYOUT
   ============================================================ */

.container {
  width: 100%;
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 24px;
}

.section {
  padding: var(--section-gap) 0;
}

/* ============================================================
   PAGE LOADER
   ============================================================ */

#page-loader {
  position: fixed;
  inset: 0;
  background: var(--bg);
  z-index: 9999;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: opacity 0.5s ease, visibility 0.5s ease;
}

#page-loader.loaded {
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
}

.loader-ring {
  width: 36px;
  height: 36px;
  border: 2px solid var(--border-hover);
  border-top-color: var(--primary);
  border-radius: 50%;
  animation: spin 0.75s linear infinite;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

/* ============================================================
   NAVIGATION
   ============================================================ */

.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--nav-height);
  z-index: 100;
  transition: background var(--transition-base), border-color var(--transition-base), backdrop-filter var(--transition-base);
  border-bottom: 1px solid transparent;
}

.nav.scrolled {
  background: rgba(8, 11, 18, 0.88);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-color: var(--border);
}

.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
}

.nav-logo {
  font-family: var(--font-heading);
  font-weight: 800;
  font-size: 1.2rem;
  letter-spacing: -0.04em;
  color: var(--text);
  transition: color var(--transition-fast);
  display: flex;
  align-items: center;
  gap: 8px;
}

.nav-logo::before {
  content: '';
  display: block;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--primary);
  box-shadow: 0 0 10px var(--primary);
}

.nav-logo:hover {
  color: var(--primary-light);
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 4px;
}

.nav-links a {
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-muted);
  padding: 7px 14px;
  border-radius: 8px;
  transition: color var(--transition-fast), background var(--transition-fast);
  letter-spacing: 0.01em;
}

.nav-links a:hover {
  color: var(--text);
  background: rgba(255, 255, 255, 0.05);
}

.nav-links a.active {
  color: var(--primary-light);
  background: var(--primary-glow);
}

/* Hamburger */
.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  cursor: pointer;
  padding: 8px;
  background: none;
  border: none;
  width: 40px;
  height: 40px;
}

.nav-toggle span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--text-muted);
  border-radius: 2px;
  transition: transform var(--transition-base), opacity var(--transition-base), background var(--transition-fast);
}

.nav-toggle:hover span {
  background: var(--text);
}

.nav-toggle.open span:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}
.nav-toggle.open span:nth-child(2) {
  opacity: 0;
  transform: scaleX(0);
}
.nav-toggle.open span:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

/* Mobile nav panel */
.nav-mobile {
  position: fixed;
  top: var(--nav-height);
  left: 0;
  right: 0;
  background: rgba(8, 11, 18, 0.97);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border);
  padding: 12px 16px 20px;
  z-index: 99;
  display: none;
  transform: translateY(-8px);
  opacity: 0;
  transition: transform var(--transition-base), opacity var(--transition-base);
}

.nav-mobile.open {
  display: block;
  transform: translateY(0);
  opacity: 1;
}

.nav-mobile ul {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.nav-mobile a {
  display: block;
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--text-muted);
  padding: 12px 16px;
  border-radius: 10px;
  transition: color var(--transition-fast), background var(--transition-fast);
}

.nav-mobile a:hover,
.nav-mobile a.active {
  color: var(--text);
  background: var(--surface-2);
}

.nav-mobile a.active {
  color: var(--primary-light);
}

/* ============================================================
   FOOTER
   ============================================================ */

.footer {
  border-top: 1px solid var(--border);
  padding: 40px 0;
  margin-top: 0;
}

.footer-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

.footer-copy {
  font-size: 0.85rem;
  color: var(--text-subtle);
}

.footer-links {
  display: flex;
  gap: 24px;
}

.footer-links a {
  font-size: 0.85rem;
  color: var(--text-subtle);
  transition: color var(--transition-fast);
}

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

/* ============================================================
   BUTTONS
   ============================================================ */

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 28px;
  border-radius: 9999px;
  font-family: var(--font-body);
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  border: 1.5px solid transparent;
  transition: transform var(--transition-base), box-shadow var(--transition-base), background var(--transition-base), border-color var(--transition-base), color var(--transition-fast);
  white-space: nowrap;
}

.btn:hover {
  transform: scale(1.04);
}

.btn:active {
  transform: scale(0.99);
}

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

.btn-primary:hover {
  background: var(--primary-light);
  border-color: var(--primary-light);
  box-shadow: var(--shadow-primary);
}

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

.btn-outline:hover {
  border-color: var(--primary);
  color: var(--primary-light);
  background: var(--primary-glow);
}

.btn-icon {
  padding: 10px;
  border-radius: 50%;
}

/* ============================================================
   SECTION LABELS & HEADERS
   ============================================================ */

.section-label {
  display: inline-block;
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.14em;
  color: var(--primary-light);
  margin-bottom: 14px;
}

.section-header {
  margin-bottom: 52px;
}

.section-header h2 {
  margin-bottom: 12px;
}

.section-header p {
  max-width: 480px;
  font-size: 1rem;
  line-height: 1.7;
}

.section-cta {
  margin-top: 48px;
  text-align: center;
}

/* ============================================================
   PROJECT CARDS
   ============================================================ */

.cards-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 20px;
}

.card {
  position: relative;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--card-radius);
  padding: 28px;
  display: flex;
  flex-direction: column;
  gap: 10px;
  overflow: hidden;
  transition: transform var(--transition-base), box-shadow var(--transition-base), border-color var(--transition-base);
}

.card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--primary), var(--accent-cyan));
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

.card:hover::before {
  transform: scaleX(1);
}

.card:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-card-hover);
  border-color: var(--border-hover);
}

.card-tag {
  display: inline-flex;
  align-items: center;
  font-size: 0.7rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--accent-green);
  background: rgba(52, 211, 153, 0.08);
  border: 1px solid rgba(52, 211, 153, 0.18);
  padding: 3px 10px;
  border-radius: 9999px;
  width: fit-content;
}

.card-tag.tag-experiment {
  color: var(--accent-cyan);
  background: rgba(34, 211, 238, 0.08);
  border-color: rgba(34, 211, 238, 0.18);
}

.card h3 {
  font-size: 1.15rem;
  color: var(--text);
  letter-spacing: -0.02em;
  margin-top: 4px;
}

.card > p {
  font-size: 0.9rem;
  color: var(--text-muted);
  line-height: 1.65;
  flex: 1;
}

.card-link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.83rem;
  font-weight: 600;
  color: var(--primary-light);
  margin-top: 10px;
  transition: gap var(--transition-fast), color var(--transition-fast);
  width: fit-content;
}

.card-link:hover {
  gap: 10px;
  color: var(--accent-cyan);
}

.card-link svg {
  width: 13px;
  height: 13px;
  flex-shrink: 0;
}

/* ============================================================
   CALLOUT / NEWSLETTER
   ============================================================ */

.callout {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 20px;
  padding: 64px 48px;
  text-align: center;
  position: relative;
  overflow: hidden;
}

.callout::before {
  content: '';
  position: absolute;
  top: -100px;
  left: 50%;
  transform: translateX(-50%);
  width: 500px;
  height: 300px;
  background: radial-gradient(ellipse, rgba(99, 102, 241, 0.12) 0%, transparent 70%);
  pointer-events: none;
}

.callout::after {
  content: '';
  position: absolute;
  bottom: -80px;
  right: -80px;
  width: 300px;
  height: 300px;
  background: radial-gradient(ellipse, rgba(34, 211, 238, 0.06) 0%, transparent 70%);
  pointer-events: none;
}

.callout h2 {
  margin-bottom: 14px;
  position: relative;
}

.callout > p {
  max-width: 440px;
  margin: 0 auto 36px;
  font-size: 0.95rem;
  position: relative;
}

.callout .btn {
  position: relative;
}

/* ============================================================
   DIVIDER
   ============================================================ */

.divider {
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--border), transparent);
}

/* ============================================================
   ANIMATIONS — SCROLL FADE-IN
   ============================================================ */

[data-animate] {
  opacity: 0;
  transform: translateY(28px);
  transition: opacity 0.65s ease, transform 0.65s ease;
}

[data-animate].is-visible {
  opacity: 1;
  transform: translateY(0);
}

[data-animate][data-delay="100"] { transition-delay: 100ms; }
[data-animate][data-delay="200"] { transition-delay: 200ms; }
[data-animate][data-delay="300"] { transition-delay: 300ms; }
[data-animate][data-delay="400"] { transition-delay: 400ms; }
[data-animate][data-delay="500"] { transition-delay: 500ms; }

/* ============================================================
   INNER PAGE HERO
   ============================================================ */

.page-hero {
  padding: calc(var(--nav-height) + 72px) 0 72px;
  text-align: center;
}

.page-hero h1 {
  margin-bottom: 16px;
}

.page-hero > .container > p {
  font-size: 1.05rem;
  max-width: 500px;
  margin: 0 auto;
  line-height: 1.7;
}

/* ============================================================
   RESPONSIVE
   ============================================================ */

@media (max-width: 768px) {
  :root {
    --section-gap: 64px;
  }

  .nav-links {
    display: none;
  }

  .nav-toggle {
    display: flex;
  }

  .footer-inner {
    flex-direction: column;
    align-items: flex-start;
    gap: 16px;
  }

  .callout {
    padding: 40px 24px;
  }

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

  .section-header p {
    max-width: 100%;
  }
}

@media (min-width: 769px) {
  .nav-mobile {
    display: none !important;
  }
}