/* KotlinLang-inspired theme — DarkForge-X */
:root {
  --kt-primary: #7F52FF;
  --kt-primary-dark: #5B3FD9;
  --kt-primary-light: #A78BFA;
  --kt-accent: #00D4AA;
  --kt-bg: #0D0D12;
  --kt-bg-elevated: #16161F;
  --kt-bg-card: #1C1C28;
  --kt-bg-hover: #252533;
  --kt-text: #E8E8F0;
  --kt-text-muted: #A0A0B8;
  --kt-text-dim: #6B6B80;
  --kt-border: #2A2A3A;
  --kt-code-bg: #12121A;
  --kt-success: #34D399;
  --kt-warning: #FBBF24;
  --kt-gradient: linear-gradient(135deg, #7F52FF 0%, #5B3FD9 50%, #00D4AA 100%);
  --kt-gradient-soft: linear-gradient(135deg, rgba(127,82,255,0.15) 0%, rgba(0,212,170,0.08) 100%);
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', 'SF Mono', Consolas, monospace;
  --radius: 12px;
  --radius-sm: 8px;
  --shadow: 0 4px 24px rgba(0,0,0,0.4);
  --shadow-lg: 0 12px 48px rgba(127,82,255,0.15);
  --transition: 0.2s cubic-bezier(0.4, 0, 0.2, 1);
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: var(--font-sans);
  background: var(--kt-bg);
  color: var(--kt-text);
  line-height: 1.6;
  min-height: 100vh;
  overflow-x: hidden;
}

/* Background ambient glow */
body::before {
  content: '';
  position: fixed;
  top: -40%;
  left: -20%;
  width: 80%;
  height: 80%;
  background: radial-gradient(ellipse, rgba(127,82,255,0.12) 0%, transparent 70%);
  pointer-events: none;
  z-index: 0;
}

body::after {
  content: '';
  position: fixed;
  bottom: -30%;
  right: -15%;
  width: 60%;
  height: 60%;
  background: radial-gradient(ellipse, rgba(0,212,170,0.08) 0%, transparent 70%);
  pointer-events: none;
  z-index: 0;
}

a { color: var(--kt-primary-light); text-decoration: none; transition: color var(--transition); }
a:hover { color: var(--kt-accent); }

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

/* ========== NAV ========== */
.navbar {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(13,13,18,0.85);
  backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--kt-border);
  padding: 0 1.5rem;
}

.nav-inner {
  max-width: 1200px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  font-weight: 700;
  font-size: 1.25rem;
  color: var(--kt-text);
  letter-spacing: -0.02em;
}

.logo svg { width: 32px; height: 32px; }

.nav-links {
  display: flex;
  align-items: center;
  gap: 0.25rem;
  list-style: none;
}

.nav-links a {
  color: var(--kt-text-muted);
  padding: 0.5rem 0.9rem;
  border-radius: var(--radius-sm);
  font-size: 0.95rem;
  font-weight: 500;
  transition: all var(--transition);
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--kt-text);
  background: var(--kt-bg-hover);
}

.nav-cta {
  background: var(--kt-primary) !important;
  color: white !important;
  padding: 0.5rem 1.1rem !important;
  border-radius: var(--radius-sm);
  font-weight: 600 !important;
}

.nav-cta:hover {
  background: var(--kt-primary-dark) !important;
  color: white !important;
}

.mobile-toggle {
  display: none;
  background: none;
  border: none;
  color: var(--kt-text);
  cursor: pointer;
  padding: 0.5rem;
}

/* ========== HERO ========== */
.hero {
  position: relative;
  z-index: 1;
  padding: 5rem 1.5rem 4rem;
  text-align: center;
  max-width: 900px;
  margin: 0 auto;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  background: var(--kt-gradient-soft);
  border: 1px solid rgba(127,82,255,0.3);
  padding: 0.35rem 1rem;
  border-radius: 999px;
  font-size: 0.85rem;
  color: var(--kt-primary-light);
  margin-bottom: 1.5rem;
  font-weight: 500;
}

.hero h1 {
  font-size: clamp(2.4rem, 6vw, 3.8rem);
  font-weight: 800;
  letter-spacing: -0.03em;
  line-height: 1.15;
  margin-bottom: 1.25rem;
  background: linear-gradient(135deg, #fff 0%, #C4B5FD 50%, #00D4AA 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero p {
  font-size: 1.2rem;
  color: var(--kt-text-muted);
  max-width: 620px;
  margin: 0 auto 2rem;
  line-height: 1.7;
}

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

.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.75rem 1.5rem;
  border-radius: var(--radius-sm);
  font-weight: 600;
  font-size: 1rem;
  transition: all var(--transition);
  cursor: pointer;
  border: none;
  text-decoration: none;
}

.btn-primary {
  background: var(--kt-primary);
  color: white;
  box-shadow: 0 4px 20px rgba(127,82,255,0.35);
}

.btn-primary:hover {
  background: var(--kt-primary-dark);
  transform: translateY(-2px);
  box-shadow: 0 6px 28px rgba(127,82,255,0.45);
  color: white;
}

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

.btn-secondary:hover {
  background: var(--kt-bg-hover);
  border-color: var(--kt-primary);
  color: var(--kt-text);
}

/* ========== LAYOUT ========== */
.container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 1.5rem;
  position: relative;
  z-index: 1;
}

.section {
  padding: 4rem 0;
}

.section-title {
  font-size: 2rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  margin-bottom: 0.75rem;
}

.section-subtitle {
  color: var(--kt-text-muted);
  font-size: 1.1rem;
  margin-bottom: 2.5rem;
  max-width: 600px;
}

/* ========== CARDS ========== */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1.5rem;
}

.card {
  background: var(--kt-bg-card);
  border: 1px solid var(--kt-border);
  border-radius: var(--radius);
  padding: 1.75rem;
  transition: all var(--transition);
  position: relative;
  overflow: hidden;
}

.card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: var(--kt-gradient);
  opacity: 0;
  transition: opacity var(--transition);
}

.card:hover {
  border-color: rgba(127,82,255,0.4);
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
}

.card:hover::before { opacity: 1; }

.card-icon {
  width: 48px;
  height: 48px;
  background: var(--kt-gradient-soft);
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 1.25rem;
  color: var(--kt-primary-light);
}

.card-icon svg { width: 24px; height: 24px; }

.card h3 {
  font-size: 1.2rem;
  font-weight: 600;
  margin-bottom: 0.5rem;
}

.card p {
  color: var(--kt-text-muted);
  font-size: 0.95rem;
  line-height: 1.6;
}

/* ========== FEATURE STRIP ========== */
.feature-strip {
  display: flex;
  flex-wrap: wrap;
  gap: 2rem;
  justify-content: center;
  padding: 2rem 0;
  border-top: 1px solid var(--kt-border);
  border-bottom: 1px solid var(--kt-border);
  margin: 2rem 0;
}

.feature-item {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  color: var(--kt-text-muted);
  font-size: 0.95rem;
  font-weight: 500;
}

.feature-item svg {
  width: 20px;
  height: 20px;
  color: var(--kt-accent);
}

/* ========== CODE BLOCKS ========== */
.code-block {
  background: var(--kt-code-bg);
  border: 1px solid var(--kt-border);
  border-radius: var(--radius);
  overflow: hidden;
  margin: 1.5rem 0;
}

.code-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.6rem 1rem;
  background: var(--kt-bg-elevated);
  border-bottom: 1px solid var(--kt-border);
  font-size: 0.8rem;
  color: var(--kt-text-dim);
  font-family: var(--font-mono);
}

.code-header .lang {
  color: var(--kt-primary-light);
  font-weight: 600;
}

.copy-btn {
  background: transparent;
  border: 1px solid var(--kt-border);
  color: var(--kt-text-muted);
  padding: 0.25rem 0.6rem;
  border-radius: 4px;
  cursor: pointer;
  font-size: 0.75rem;
  transition: all var(--transition);
}

.copy-btn:hover {
  background: var(--kt-bg-hover);
  color: var(--kt-text);
}

pre {
  padding: 1.25rem 1.5rem;
  overflow-x: auto;
  font-family: var(--font-mono);
  font-size: 0.9rem;
  line-height: 1.65;
  color: #D4D4E0;
}

code {
  font-family: var(--font-mono);
  font-size: 0.9em;
}

.inline-code {
  background: var(--kt-bg-hover);
  padding: 0.15rem 0.4rem;
  border-radius: 4px;
  font-size: 0.88em;
  color: var(--kt-primary-light);
}

/* Syntax colors */
.kw { color: #C792EA; }
.fn { color: #82AAFF; }
.str { color: #C3E88D; }
.num { color: #F78C6C; }
.cm { color: #697098; }
.tp { color: #FFCB6B; }
.op { color: #89DDFF; }

/* ========== STEPS ========== */
.steps {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.step {
  display: flex;
  gap: 1.25rem;
  align-items: flex-start;
}

.step-num {
  flex-shrink: 0;
  width: 36px;
  height: 36px;
  background: var(--kt-gradient);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 0.95rem;
  color: white;
}

.step-content h3 {
  font-size: 1.15rem;
  margin-bottom: 0.35rem;
}

.step-content p {
  color: var(--kt-text-muted);
  font-size: 0.95rem;
}

/* ========== TABS ========== */
.tabs {
  display: flex;
  gap: 0.25rem;
  margin-bottom: 1rem;
  border-bottom: 1px solid var(--kt-border);
  padding-bottom: 0;
  flex-wrap: wrap;
}

.tab {
  padding: 0.6rem 1.1rem;
  background: transparent;
  border: none;
  color: var(--kt-text-muted);
  font-size: 0.9rem;
  font-weight: 500;
  cursor: pointer;
  border-bottom: 2px solid transparent;
  margin-bottom: -1px;
  transition: all var(--transition);
  font-family: var(--font-sans);
}

.tab:hover { color: var(--kt-text); }
.tab.active {
  color: var(--kt-primary-light);
  border-bottom-color: var(--kt-primary);
}

.tab-panel { display: none; }
.tab-panel.active { display: block; }

/* ========== PAGE HEADER ========== */
.page-header {
  padding: 3.5rem 0 2rem;
  border-bottom: 1px solid var(--kt-border);
  margin-bottom: 2.5rem;
}

.page-header h1 {
  font-size: 2.5rem;
  font-weight: 800;
  letter-spacing: -0.03em;
  margin-bottom: 0.75rem;
}

.page-header p {
  color: var(--kt-text-muted);
  font-size: 1.15rem;
  max-width: 640px;
}

.breadcrumb {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.85rem;
  color: var(--kt-text-dim);
  margin-bottom: 1rem;
}

.breadcrumb a { color: var(--kt-text-muted); }
.breadcrumb a:hover { color: var(--kt-primary-light); }
.breadcrumb svg { width: 14px; height: 14px; opacity: 0.5; }

/* ========== CONTENT ========== */
.content-block {
  margin-bottom: 3rem;
}

.content-block h2 {
  font-size: 1.6rem;
  font-weight: 700;
  margin-bottom: 1rem;
  letter-spacing: -0.02em;
}

.content-block h3 {
  font-size: 1.25rem;
  font-weight: 600;
  margin: 1.75rem 0 0.75rem;
}

.content-block p {
  color: var(--kt-text-muted);
  margin-bottom: 1rem;
  line-height: 1.7;
}

.content-block ul, .content-block ol {
  color: var(--kt-text-muted);
  padding-left: 1.5rem;
  margin-bottom: 1rem;
}

.content-block li {
  margin-bottom: 0.5rem;
  line-height: 1.6;
}

.content-block li strong { color: var(--kt-text); }

.note {
  background: rgba(127,82,255,0.08);
  border-left: 3px solid var(--kt-primary);
  padding: 1rem 1.25rem;
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  margin: 1.5rem 0;
  color: var(--kt-text-muted);
  font-size: 0.95rem;
}

.note strong { color: var(--kt-primary-light); }

/* ========== FOOTER ========== */
.footer {
  position: relative;
  z-index: 1;
  border-top: 1px solid var(--kt-border);
  padding: 3rem 1.5rem 2rem;
  margin-top: 4rem;
  background: var(--kt-bg-elevated);
}

.footer-inner {
  max-width: 1100px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 2rem;
}

.footer-brand {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.footer-brand .logo { font-size: 1.1rem; }
.footer-brand p {
  color: var(--kt-text-dim);
  font-size: 0.9rem;
  max-width: 280px;
}

.footer-col h4 {
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--kt-text-dim);
  margin-bottom: 1rem;
}

.footer-col a {
  display: block;
  color: var(--kt-text-muted);
  font-size: 0.9rem;
  margin-bottom: 0.5rem;
  transition: color var(--transition);
}

.footer-col a:hover { color: var(--kt-primary-light); }

.footer-bottom {
  max-width: 1100px;
  margin: 2.5rem auto 0;
  padding-top: 1.5rem;
  border-top: 1px solid var(--kt-border);
  display: flex;
  justify-content: space-between;
  align-items: center;
  color: var(--kt-text-dim);
  font-size: 0.85rem;
}

/* ========== RESPONSIVE ========== */
@media (max-width: 768px) {
  .nav-links {
    display: none;
    position: absolute;
    top: 64px;
    left: 0;
    right: 0;
    background: var(--kt-bg-elevated);
    flex-direction: column;
    padding: 1rem;
    border-bottom: 1px solid var(--kt-border);
    gap: 0.25rem;
  }

  .nav-links.open { display: flex; }

  .mobile-toggle { display: block; }

  .hero { padding: 3.5rem 1.25rem 3rem; }
  .hero h1 { font-size: 2.2rem; }

  .footer-inner {
    grid-template-columns: 1fr 1fr;
  }

  .footer-bottom {
    flex-direction: column;
    gap: 0.75rem;
    text-align: center;
  }

  .section { padding: 3rem 0; }
}

@media (max-width: 480px) {
  .footer-inner { grid-template-columns: 1fr; }
  .hero-actions { flex-direction: column; }
  .btn { width: 100%; justify-content: center; }
}

/* Utility */
.text-accent { color: var(--kt-accent); }
.text-primary { color: var(--kt-primary-light); }
.mt-2 { margin-top: 2rem; }
.mb-2 { margin-bottom: 2rem; }
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0,0,0,0);
  border: 0;
}