/* ==========================================================================
   AI Creative Solution — Global Design System
   ========================================================================== */

/* ---- Design Tokens ---- */
:root {
  /* Color — Base */
  --bg-primary: #0A0B0D;
  --bg-secondary: #131519;
  --bg-tertiary: #1C1F24;
  --border-subtle: #26292F;
  --text-primary: #F5F6F7;
  --text-secondary: #A8ADB5;
  --text-tertiary: #6B7078;

  /* Color — Accent */
  --accent-primary: #4F7CFF;
  --accent-hover: #6B90FF;
  --accent-glow: rgba(79, 124, 255, 0.18);

  /* Color — Semantic */
  --success: #3DD68C;
  --warning: #F5A623;
  --error: #F1554C;

  /* Typography */
  --font-display: 'General Sans', 'Segoe UI', sans-serif;
  --font-body: 'General Sans', 'Segoe UI', sans-serif;
  --font-mono: 'JetBrains Mono', 'Courier New', monospace;

  /* Spacing scale (4px base) */
  --space-1: 4px;
  --space-2: 8px;
  --space-3: 12px;
  --space-4: 16px;
  --space-6: 24px;
  --space-8: 32px;
  --space-12: 48px;
  --space-16: 64px;
  --space-24: 96px;
  --space-32: 128px;

  /* Radius */
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;

  /* Layout */
  --container-max: 1280px;
  --container-wide: 1440px;

  /* Motion */
  --ease-standard: cubic-bezier(0.2, 0.8, 0.2, 1);
}

/* ---- Reset ---- */
*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--bg-primary);
  color: var(--text-primary);
  font-family: var(--font-body);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}
img, svg { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }
ul, ol { padding: 0; margin: 0; list-style: none; }
button { font-family: inherit; cursor: pointer; }

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
    scroll-behavior: auto !important;
  }
}

/* Visible focus state — accessibility requirement */
:focus-visible {
  outline: 2px solid var(--accent-primary);
  outline-offset: 3px;
  border-radius: 4px;
}

/* ---- Typography ---- */
h1, h2, h3, h4 {
  font-family: var(--font-display);
  font-weight: 600;
  line-height: 1.15;
  margin: 0 0 var(--space-4);
  color: var(--text-primary);
}
.text-display { font-size: clamp(2.5rem, 6vw, 5rem); font-weight: 600; letter-spacing: -0.02em; }
h1, .text-h1 { font-size: clamp(2rem, 4.5vw, 2.75rem); letter-spacing: -0.01em; }
h2, .text-h2 { font-size: clamp(1.6rem, 3.5vw, 2.25rem); }
h3, .text-h3 { font-size: 1.5rem; }
p { margin: 0 0 var(--space-4); color: var(--text-secondary); }
.text-body-lg { font-size: 1.125rem; line-height: 1.6; color: var(--text-secondary); }
.text-caption { font-size: 0.875rem; color: var(--text-tertiary); }
.text-mono { font-family: var(--font-mono); }
.text-accent { color: var(--accent-primary); }

/* ---- Layout ---- */
.container {
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--space-6);
}
.container-wide {
  max-width: var(--container-wide);
  margin: 0 auto;
  padding: 0 var(--space-6);
}
.section {
  padding: var(--space-24) 0;
}
@media (max-width: 768px) {
  .section { padding: var(--space-16) 0; }
}
.grid {
  display: grid;
  gap: var(--space-6);
}
.grid-2 { grid-template-columns: repeat(2, 1fr); }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-4 { grid-template-columns: repeat(4, 1fr); }
@media (max-width: 900px) {
  .grid-3, .grid-4 { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 600px) {
  .grid-2, .grid-3, .grid-4 { grid-template-columns: 1fr; }
}
.flex { display: flex; align-items: center; }
.flex-between { display: flex; align-items: center; justify-content: space-between; }
.flex-col { display: flex; flex-direction: column; }
.gap-2 { gap: var(--space-2); }
.gap-4 { gap: var(--space-4); }
.gap-6 { gap: var(--space-6); }
.text-center { text-align: center; }

/* ---- Header / Nav ---- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(10, 11, 13, 0.85);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border-subtle);
}
.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-4) 0;
}
.logo {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 1.1rem;
  color: var(--text-primary);
}
.nav-links {
  display: flex;
  gap: var(--space-8);
  align-items: center;
}
.nav-links a {
  color: var(--text-secondary);
  font-size: 0.95rem;
  transition: color 0.15s var(--ease-standard);
}
.nav-links a:hover { color: var(--text-primary); }
.nav-toggle {
  display: none;
  background: none;
  border: none;
  color: var(--text-primary);
}
@media (max-width: 860px) {
  .nav-links {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border-subtle);
    flex-direction: column;
    align-items: flex-start;
    padding: var(--space-6);
    gap: var(--space-4);
  }
  .nav-links.is-open { display: flex; }
  .nav-toggle { display: block; }
}

/* ---- Buttons ---- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  padding: 0.85rem 1.5rem;
  border-radius: var(--radius-sm);
  font-weight: 600;
  font-size: 0.95rem;
  border: 1px solid transparent;
  transition: all 0.15s var(--ease-standard);
  white-space: nowrap;
}
.btn-primary {
  background: var(--accent-primary);
  color: #ffffff;
}
.btn-primary:hover {
  background: var(--accent-hover);
  box-shadow: 0 0 24px var(--accent-glow);
}
.btn-secondary {
  background: transparent;
  border-color: var(--border-subtle);
  color: var(--text-primary);
}
.btn-secondary:hover { border-color: var(--accent-primary); }
.btn-ghost {
  background: none;
  color: var(--accent-primary);
  padding-left: 0;
  padding-right: 0;
}
.btn-ghost:hover { color: var(--accent-hover); }

/* ---- Cards ---- */
.card {
  background: var(--bg-secondary);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: var(--space-8);
  transition: border-color 0.2s var(--ease-standard), transform 0.2s var(--ease-standard);
}
.card:hover {
  border-color: rgba(79, 124, 255, 0.4);
  transform: translateY(-2px);
}

/* ---- Badges/Tags ---- */
.badge {
  display: inline-block;
  background: var(--bg-tertiary);
  color: var(--text-secondary);
  font-size: 0.8rem;
  padding: 0.3rem 0.75rem;
  border-radius: 999px;
  border: 1px solid var(--border-subtle);
}

/* ---- Hero glow background ---- */
.hero-glow {
  position: relative;
  overflow: hidden;
}
.hero-glow::before {
  content: '';
  position: absolute;
  top: -20%;
  left: 50%;
  transform: translateX(-50%);
  width: 900px;
  height: 500px;
  background: radial-gradient(circle, var(--accent-glow) 0%, transparent 70%);
  pointer-events: none;
  z-index: 0;
}
.hero-glow > * { position: relative; z-index: 1; }

/* ---- FAQ (native details/summary — accessible by default) ---- */
.faq-item {
  border-bottom: 1px solid var(--border-subtle);
  padding: var(--space-4) 0;
}
.faq-item summary {
  cursor: pointer;
  font-weight: 600;
  color: var(--text-primary);
  list-style: none;
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item summary::after {
  content: '+';
  color: var(--accent-primary);
  font-size: 1.3rem;
}
.faq-item[open] summary::after { content: '–'; }
.faq-item p { margin-top: var(--space-3); }

/* ---- Footer ---- */
.site-footer {
  border-top: 1px solid var(--border-subtle);
  padding: var(--space-16) 0 var(--space-8);
  margin-top: var(--space-24);
}
.footer-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--space-8);
  margin-bottom: var(--space-12);
}
.footer-grid h4 {
  font-size: 0.85rem;
  color: var(--text-tertiary);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: var(--space-4);
}
.footer-grid a {
  display: block;
  color: var(--text-secondary);
  font-size: 0.9rem;
  padding: var(--space-1) 0;
}
.footer-grid a:hover { color: var(--text-primary); }
.footer-bottom {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-top: var(--space-8);
  border-top: 1px solid var(--border-subtle);
  color: var(--text-tertiary);
  font-size: 0.85rem;
  flex-wrap: wrap;
  gap: var(--space-4);
}
@media (max-width: 768px) {
  .footer-grid { grid-template-columns: repeat(2, 1fr); }
}

/* ---- Scroll reveal utility ---- */
.reveal {
  opacity: 0;
  transform: translateY(16px);
  transition: opacity 0.6s var(--ease-standard), transform 0.6s var(--ease-standard);
}
.reveal.is-visible {
  opacity: 1;
  transform: translateY(0);
}