/* ============================================================
   THE AI-ENABLED CODER — Global Design System
   Concept 4: Code Builder | v1.0 | 2026-03-14
   ============================================================ */

/* ── Fonts ── */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700;800&family=JetBrains+Mono:wght@400;700&display=swap');

/* ── CSS Variables ── */
:root {
  /* Colors */
  --color-bg:           #0A0E1A;
  --color-surface:      #111827;
  --color-surface-2:    #1a2235;
  --color-border:       #1F2937;
  --color-border-hover: #374151;

  --color-amber:        #F59E0B;
  --color-amber-light:  #FCD34D;
  --color-blue:         #3B82F6;
  --color-blue-light:   #60A5FA;
  --color-cyan:         #06B6D4;
  --color-cyan-light:   #67E8F9;
  --color-green:        #10B981;
  --color-red:          #EF4444;

  --color-text:         #F9FAFB;
  --color-text-muted:   #9CA3AF;
  --color-text-faint:   #4B5563;

  /* Typography */
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', system-ui, sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', 'Cascadia Code', monospace;

  /* Spacing */
  --space-xs:  4px;
  --space-sm:  8px;
  --space-md:  16px;
  --space-lg:  24px;
  --space-xl:  40px;
  --space-2xl: 64px;
  --space-3xl: 96px;

  /* Layout */
  --max-w-content: 1200px;
  --max-w-article: 740px;
  --nav-height: 64px;

  /* Borders */
  --radius-sm:  6px;
  --radius-md:  12px;
  --radius-lg:  20px;
  --radius-xl:  32px;

  /* Shadows / Glows */
  --glow-amber: 0 0 0 1px var(--color-amber), 0 4px 24px rgba(245, 158, 11, 0.12);
  --glow-blue:  0 0 0 1px var(--color-blue),  0 4px 24px rgba(59, 130, 246, 0.12);
  --glow-cyan:  0 0 0 1px var(--color-cyan),  0 4px 24px rgba(6, 182, 212, 0.12);

  /* Transitions */
  --transition: 150ms ease;
  --transition-slow: 300ms ease;
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-sans);
  font-size: 1rem;
  line-height: 1.75;
  color: var(--color-text);
  background-color: var(--color-bg);
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

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

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

a:hover {
  color: var(--color-cyan-light);
}

ul, ol {
  list-style: none;
}

button {
  cursor: pointer;
  font-family: inherit;
  border: none;
  background: none;
}

/* ── Typography ── */
h1, h2, h3, h4, h5, h6 {
  font-weight: 700;
  line-height: 1.2;
  color: var(--color-text);
  letter-spacing: -0.02em;
}

h1 { font-size: clamp(2rem, 5vw, 3.5rem); font-weight: 800; }
h2 { font-size: clamp(1.5rem, 3vw, 2rem); }
h3 { font-size: 1.25rem; font-weight: 600; }
h4 { font-size: 1.1rem; font-weight: 600; }

p { margin-bottom: 1rem; }
p:last-child { margin-bottom: 0; }

strong { font-weight: 700; color: var(--color-text); }
em { font-style: italic; }

code {
  font-family: var(--font-mono);
  font-size: 0.875em;
  color: var(--color-cyan);
  background: rgba(6, 182, 212, 0.08);
  border: 1px solid rgba(6, 182, 212, 0.15);
  padding: 2px 6px;
  border-radius: var(--radius-sm);
}

pre {
  background: #0d1117;
  border: 1px solid var(--color-border);
  border-left: 3px solid var(--color-cyan);
  border-radius: var(--radius-md);
  padding: var(--space-lg);
  overflow-x: auto;
  margin: var(--space-lg) 0;
}

pre code {
  font-size: 0.875rem;
  color: #e6edf3;
  background: none;
  border: none;
  padding: 0;
}

/* ── Layout ── */
.container {
  width: 100%;
  max-width: var(--max-w-content);
  margin: 0 auto;
  padding: 0 var(--space-lg);
}

.container--narrow {
  max-width: var(--max-w-article);
}

.section {
  padding: var(--space-3xl) 0;
}

.section--sm {
  padding: var(--space-2xl) 0;
}

/* ── Navigation ── */
.nav {
  position: sticky;
  top: 0;
  z-index: 100;
  height: var(--nav-height);
  background: rgba(10, 14, 26, 0.92);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-border);
}

.nav__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
  max-width: var(--max-w-content);
  margin: 0 auto;
  padding: 0 var(--space-lg);
}

.nav__logo {
  display: flex;
  align-items: center;
  text-decoration: none;
  flex-shrink: 0;
}

.nav__logo svg {
  height: 36px;
  width: auto;
}

.nav__links {
  display: flex;
  align-items: center;
  gap: var(--space-xl);
}

.nav__link {
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--color-text-muted);
  text-decoration: none;
  transition: color var(--transition);
  white-space: nowrap;
}

.nav__link:hover,
.nav__link.active {
  color: var(--color-text);
}

.nav__link.active {
  border-bottom: 2px solid var(--color-amber);
  padding-bottom: 2px;
}

.nav__cta {
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--color-bg);
  background: var(--color-amber);
  padding: 8px 18px;
  border-radius: var(--radius-sm);
  transition: opacity var(--transition), transform var(--transition);
}

.nav__cta:hover {
  opacity: 0.9;
  transform: scale(1.02);
  color: var(--color-bg);
}

.nav__hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  padding: 8px;
  cursor: pointer;
}

.nav__hamburger span {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--color-text);
  border-radius: 2px;
  transition: transform var(--transition), opacity var(--transition);
}

/* Mobile Menu */
.nav__mobile {
  display: none;
  position: fixed;
  inset: var(--nav-height) 0 0 0;
  background: var(--color-bg);
  z-index: 99;
  flex-direction: column;
  padding: var(--space-xl);
  overflow-y: auto;
}

.nav__mobile.open {
  display: flex;
}

.nav__mobile-link {
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--color-text-muted);
  padding: var(--space-md) 0;
  border-bottom: 1px solid var(--color-border);
  text-decoration: none;
  transition: color var(--transition);
}

.nav__mobile-link:hover {
  color: var(--color-text);
}

@media (max-width: 768px) {
  .nav__links {
    display: none;
  }
  .nav__hamburger {
    display: flex;
  }
}

/* ── Buttons ── */
.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  font-size: 1rem;
  font-weight: 600;
  padding: 14px 28px;
  border-radius: var(--radius-sm);
  transition: opacity var(--transition), transform var(--transition), box-shadow var(--transition);
  text-decoration: none;
  cursor: pointer;
  border: none;
  font-family: inherit;
  white-space: nowrap;
}

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

.btn--primary:hover {
  opacity: 0.9;
  transform: scale(1.02);
  box-shadow: 0 0 24px rgba(245, 158, 11, 0.3);
  color: var(--color-bg);
}

.btn--ghost {
  background: transparent;
  color: var(--color-amber);
  border: 2px solid var(--color-amber);
}

.btn--ghost:hover {
  background: rgba(245, 158, 11, 0.08);
  transform: scale(1.02);
  color: var(--color-amber);
}

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

.btn--secondary:hover {
  border-color: var(--color-amber);
  color: var(--color-text);
}

.btn--sm {
  font-size: 0.875rem;
  padding: 8px 16px;
}

/* ── Cards ── */
.card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: var(--space-lg);
  transition: border-color var(--transition), box-shadow var(--transition), transform var(--transition);
  text-decoration: none;
  display: block;
  color: inherit;
}

.card:hover {
  border-color: var(--color-amber);
  box-shadow: var(--glow-amber);
  transform: translateY(-2px);
  color: inherit;
}

.card__tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--color-amber);
  background: rgba(245, 158, 11, 0.1);
  border: 1px solid rgba(245, 158, 11, 0.2);
  padding: 4px 10px;
  border-radius: 100px;
  margin-bottom: var(--space-md);
}

.card__emoji {
  font-size: 2rem;
  margin-bottom: var(--space-md);
  display: block;
}

.card__title {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: var(--space-sm);
  line-height: 1.3;
}

.card__desc {
  font-size: 0.9rem;
  color: var(--color-text-muted);
  line-height: 1.6;
}

.card__meta {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  margin-top: var(--space-md);
  padding-top: var(--space-md);
  border-top: 1px solid var(--color-border);
  font-size: 0.8rem;
  color: var(--color-text-faint);
}

.card__count {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--color-cyan);
}

/* ── Grids ── */
.grid {
  display: grid;
  gap: var(--space-lg);
}

.grid--3 { grid-template-columns: repeat(3, 1fr); }
.grid--2 { grid-template-columns: repeat(2, 1fr); }

@media (max-width: 1024px) {
  .grid--3 { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 640px) {
  .grid--3,
  .grid--2 { grid-template-columns: 1fr; }
}

/* ── Badges ── */
.badge {
  display: inline-flex;
  align-items: center;
  font-size: 0.75rem;
  font-weight: 600;
  padding: 3px 10px;
  border-radius: 100px;
}

.badge--amber {
  background: rgba(245, 158, 11, 0.15);
  color: var(--color-amber);
  border: 1px solid rgba(245, 158, 11, 0.3);
}

.badge--blue {
  background: rgba(59, 130, 246, 0.15);
  color: var(--color-blue-light);
  border: 1px solid rgba(59, 130, 246, 0.3);
}

.badge--cyan {
  background: rgba(6, 182, 212, 0.15);
  color: var(--color-cyan);
  border: 1px solid rgba(6, 182, 212, 0.3);
}

.badge--green {
  background: rgba(16, 185, 129, 0.15);
  color: var(--color-green);
  border: 1px solid rgba(16, 185, 129, 0.3);
}

/* ── Stats Bar ── */
.stats-bar {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-xl);
  flex-wrap: wrap;
}

.stat {
  text-align: center;
}

.stat__number {
  font-size: 1.75rem;
  font-weight: 800;
  color: var(--color-amber);
  display: block;
  line-height: 1;
  margin-bottom: 4px;
}

.stat__label {
  font-size: 0.8rem;
  color: var(--color-text-muted);
  font-weight: 500;
}

.stat-divider {
  width: 1px;
  height: 40px;
  background: var(--color-border);
}

@media (max-width: 640px) {
  .stat-divider { display: none; }
}

/* ── Section Headers ── */
.section-header {
  margin-bottom: var(--space-2xl);
}

.section-header--center {
  text-align: center;
}

.section-header__label {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--color-amber);
  margin-bottom: var(--space-md);
}

.section-header__label::before {
  content: '';
  display: block;
  width: 20px;
  height: 2px;
  background: var(--color-amber);
}

.section-header__title {
  margin-bottom: var(--space-md);
}

.section-header__title .highlight {
  color: var(--color-cyan);
}

.section-header__desc {
  font-size: 1.1rem;
  color: var(--color-text-muted);
  max-width: 600px;
  line-height: 1.7;
}

.section-header--center .section-header__desc {
  margin: 0 auto;
}

/* ── Breadcrumb ── */
.breadcrumb {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  font-size: 0.875rem;
  color: var(--color-text-faint);
  margin-bottom: var(--space-xl);
}

.breadcrumb a {
  color: var(--color-text-muted);
  text-decoration: none;
  transition: color var(--transition);
}

.breadcrumb a:hover {
  color: var(--color-amber);
}

.breadcrumb__sep {
  color: var(--color-border);
}

/* ── Hero ── */
.hero {
  padding: var(--space-3xl) 0;
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  top: -200px;
  right: -200px;
  width: 600px;
  height: 600px;
  background: radial-gradient(circle, rgba(6, 182, 212, 0.06) 0%, transparent 70%);
  pointer-events: none;
}

.hero::after {
  content: '';
  position: absolute;
  bottom: -100px;
  left: -100px;
  width: 400px;
  height: 400px;
  background: radial-gradient(circle, rgba(245, 158, 11, 0.04) 0%, transparent 70%);
  pointer-events: none;
}

.hero__content {
  position: relative;
  z-index: 1;
}

.hero__eyebrow {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--color-amber);
  background: rgba(245, 158, 11, 0.08);
  border: 1px solid rgba(245, 158, 11, 0.2);
  padding: 6px 14px;
  border-radius: 100px;
  margin-bottom: var(--space-lg);
}

.hero__title {
  font-size: clamp(2.25rem, 5.5vw, 4rem);
  font-weight: 800;
  letter-spacing: -0.03em;
  line-height: 1.1;
  margin-bottom: var(--space-lg);
}

.hero__title .gradient-text {
  background: linear-gradient(135deg, var(--color-cyan), var(--color-blue));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero__subtitle {
  font-size: clamp(1rem, 2vw, 1.25rem);
  color: var(--color-text-muted);
  line-height: 1.7;
  max-width: 600px;
  margin-bottom: var(--space-xl);
}

.hero__actions {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  flex-wrap: wrap;
}

/* ── Terminal Block ── */
.terminal {
  background: #0d1117;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  overflow: hidden;
  font-family: var(--font-mono);
  font-size: 0.875rem;
}

.terminal__bar {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  padding: 10px var(--space-md);
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
}

.terminal__dot {
  width: 12px;
  height: 12px;
  border-radius: 50%;
}

.terminal__dot--red    { background: #ff5f57; }
.terminal__dot--yellow { background: #febc2e; }
.terminal__dot--green  { background: #28c840; }

.terminal__title {
  font-size: 0.75rem;
  color: var(--color-text-faint);
  margin-left: auto;
  margin-right: auto;
}

.terminal__body {
  padding: var(--space-lg);
  line-height: 1.8;
}

.terminal__line {
  display: flex;
  gap: var(--space-sm);
  margin-bottom: 4px;
}

.terminal__prompt { color: var(--color-green); }
.terminal__cmd    { color: var(--color-text); }
.terminal__out    { color: var(--color-text-muted); padding-left: 20px; }
.terminal__ai     { color: var(--color-cyan); }
.terminal__success { color: var(--color-green); }
.terminal__cursor {
  display: inline-block;
  width: 8px;
  height: 1em;
  background: var(--color-cyan);
  animation: blink 1s infinite;
  vertical-align: middle;
}

@keyframes blink {
  0%, 100% { opacity: 1; }
  50%       { opacity: 0; }
}

/* ── Callout / Alert Boxes ── */
.callout {
  border-radius: var(--radius-md);
  padding: var(--space-lg);
  border-left: 4px solid;
  margin: var(--space-lg) 0;
}

.callout--tip {
  background: rgba(16, 185, 129, 0.06);
  border-color: var(--color-green);
}

.callout--warning {
  background: rgba(245, 158, 11, 0.06);
  border-color: var(--color-amber);
}

.callout--info {
  background: rgba(6, 182, 212, 0.06);
  border-color: var(--color-cyan);
}

.callout__label {
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  margin-bottom: var(--space-sm);
}

.callout--tip    .callout__label { color: var(--color-green); }
.callout--warning .callout__label { color: var(--color-amber); }
.callout--info   .callout__label { color: var(--color-cyan); }

/* ── Reading Progress Bar ── */
.reading-progress {
  position: fixed;
  top: var(--nav-height);
  left: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--color-amber), var(--color-cyan));
  width: 0%;
  z-index: 101;
  transition: width 0.1s linear;
}

/* ── Footer ── */
.footer {
  background: var(--color-surface);
  border-top: 1px solid var(--color-border);
  padding: var(--space-2xl) 0 var(--space-lg);
  margin-top: var(--space-3xl);
}

.footer__inner {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: var(--space-2xl);
  margin-bottom: var(--space-2xl);
}

.footer__brand p {
  color: var(--color-text-muted);
  font-size: 0.9rem;
  margin-top: var(--space-md);
  max-width: 280px;
  line-height: 1.7;
}

.footer__col-title {
  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--color-text-faint);
  margin-bottom: var(--space-md);
}

.footer__links {
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
}

.footer__link {
  font-size: 0.9rem;
  color: var(--color-text-muted);
  text-decoration: none;
  transition: color var(--transition);
}

.footer__link:hover {
  color: var(--color-amber);
}

.footer__bottom {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: var(--space-lg);
  border-top: 1px solid var(--color-border);
  font-size: 0.8rem;
  color: var(--color-text-faint);
}

.footer__tagline {
  font-family: var(--font-mono);
  color: var(--color-cyan);
}

@media (max-width: 768px) {
  .footer__inner {
    grid-template-columns: 1fr 1fr;
    gap: var(--space-xl);
  }
  .footer__brand {
    grid-column: 1 / -1;
  }
}

@media (max-width: 480px) {
  .footer__inner {
    grid-template-columns: 1fr;
  }
  .footer__bottom {
    flex-direction: column;
    gap: var(--space-sm);
    text-align: center;
  }
}

/* ── Utilities ── */
.text-center { text-align: center; }
.text-muted   { color: var(--color-text-muted); }
.text-amber   { color: var(--color-amber); }
.text-cyan    { color: var(--color-cyan); }
.text-green   { color: var(--color-green); }

.mt-sm  { margin-top: var(--space-sm); }
.mt-md  { margin-top: var(--space-md); }
.mt-lg  { margin-top: var(--space-lg); }
.mt-xl  { margin-top: var(--space-xl); }
.mt-2xl { margin-top: var(--space-2xl); }

.mb-sm  { margin-bottom: var(--space-sm); }
.mb-md  { margin-bottom: var(--space-md); }
.mb-lg  { margin-bottom: var(--space-lg); }
.mb-xl  { margin-bottom: var(--space-xl); }
.mb-2xl { margin-bottom: var(--space-2xl); }

.hidden { display: none !important; }
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border-width: 0;
}

/* ── Dividers ── */
.divider {
  height: 1px;
  background: var(--color-border);
  margin: var(--space-xl) 0;
}

/* ── Skeleton Loader ── */
.skeleton {
  background: linear-gradient(90deg, var(--color-surface) 25%, var(--color-surface-2) 50%, var(--color-surface) 75%);
  background-size: 200% 100%;
  animation: skeleton-loading 1.5s infinite;
  border-radius: var(--radius-sm);
}

@keyframes skeleton-loading {
  0%   { background-position: 200% 0; }
  100% { background-position: -200% 0; }
}

/* ── Scroll Animations ── */
.fade-up {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.fade-up.visible {
  opacity: 1;
  transform: translateY(0);
}