/* Delta Lang — Design System
   Space Grotesk headings · JetBrains Mono code · Inter body
   Dark code-centric palette — #07070f background, indigo-purple accent
   ─────────────────────────────────────────────────────────────────────── */

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

:root {
  /* Palette */
  --bg:           #07070f;
  --bg-2:         #0c0c18;
  --bg-3:         #111124;
  --surface:      rgba(255,255,255,0.035);
  --surface-2:    rgba(255,255,255,0.06);
  --border:       rgba(255,255,255,0.07);
  --border-2:     rgba(255,255,255,0.12);

  --accent:       #7c3aed;
  --accent-2:     #a78bfa;
  --accent-glow:  rgba(124,58,237,0.25);

  --green:        #10b981;
  --green-dim:    rgba(16,185,129,0.15);
  --red:          #f43f5e;
  --red-dim:      rgba(244,63,94,0.12);
  --yellow:       #f59e0b;

  --text:         #e2e8f0;
  --text-2:       #94a3b8;
  --text-3:       #475569;

  /* Typography */
  --font-display: 'Space Grotesk', system-ui, sans-serif;
  --font-body:    'Inter', system-ui, sans-serif;
  --font-mono:    'JetBrains Mono', 'Fira Code', monospace;

  /* Spacing */
  --radius:       10px;
  --radius-lg:    16px;
  --radius-sm:    6px;
}

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

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

/* ── Utility ─────────────────────────────────────────────────────────────── */

.container {
  max-width: 1140px;
  margin: 0 auto;
  padding: 0 24px;
}

/* ── Nav ─────────────────────────────────────────────────────────────────── */

.nav {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(7,7,15,0.8);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--border);
}

.nav-inner {
  max-width: 1140px;
  margin: 0 auto;
  padding: 0 24px;
  height: 62px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: 8px;
  text-decoration: none;
  font-family: var(--font-display);
  font-weight: 700;
}

.logo-delta {
  font-size: 1.4rem;
  color: var(--accent-2);
  line-height: 1;
}

.logo-word {
  font-size: 1.05rem;
  color: var(--text);
  letter-spacing: -0.02em;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 32px;
}

.nav-links a {
  color: var(--text-2);
  text-decoration: none;
  font-size: 0.9rem;
  font-weight: 500;
  transition: color 0.15s;
  display: flex;
  align-items: center;
  gap: 6px;
}

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

.nav-gh {
  color: var(--text) !important;
  background: var(--surface-2);
  border: 1px solid var(--border-2);
  padding: 6px 14px;
  border-radius: var(--radius-sm);
  font-size: 0.85rem !important;
}

.nav-gh:hover {
  border-color: var(--accent);
  background: rgba(124,58,237,0.1) !important;
}

.nav-mobile-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px;
}

.nav-mobile-toggle span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--text-2);
  border-radius: 2px;
  transition: all 0.2s;
}

/* ── Buttons ─────────────────────────────────────────────────────────────── */

.btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 10px 22px;
  border-radius: var(--radius);
  font-family: var(--font-display);
  font-size: 0.9rem;
  font-weight: 600;
  text-decoration: none;
  transition: all 0.15s;
  cursor: pointer;
  border: none;
  white-space: nowrap;
}

.btn-primary {
  background: var(--accent);
  color: #fff;
  box-shadow: 0 0 0 0 var(--accent-glow);
}

.btn-primary:hover {
  background: #6d28d9;
  transform: translateY(-1px);
  box-shadow: 0 8px 24px var(--accent-glow);
}

.btn-ghost {
  background: var(--surface);
  color: var(--text-2);
  border: 1px solid var(--border-2);
}

.btn-ghost:hover {
  background: var(--surface-2);
  color: var(--text);
  border-color: rgba(167,139,250,0.3);
}

.btn-lg { padding: 13px 28px; font-size: 0.95rem; }

/* ── Hero ─────────────────────────────────────────────────────────────────── */

.hero {
  position: relative;
  overflow: hidden;
  padding: 110px 0 90px;
  background: radial-gradient(ellipse 90% 70% at 50% -10%, rgba(124,58,237,0.18) 0%, transparent 65%);
}

.hero-bg-delta {
  position: absolute;
  top: -60px;
  right: -80px;
  font-family: var(--font-display);
  font-size: clamp(280px, 40vw, 520px);
  font-weight: 700;
  color: rgba(124,58,237,0.045);
  line-height: 1;
  pointer-events: none;
  user-select: none;
  letter-spacing: -0.05em;
}

.hero-grid-overlay {
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(124,58,237,0.04) 1px, transparent 1px),
    linear-gradient(90deg, rgba(124,58,237,0.04) 1px, transparent 1px);
  background-size: 60px 60px;
  mask-image: radial-gradient(ellipse 80% 80% at 50% 0%, black 0%, transparent 70%);
  pointer-events: none;
}

.hero-inner {
  position: relative;
  z-index: 1;
  text-align: center;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: rgba(124,58,237,0.1);
  border: 1px solid rgba(124,58,237,0.25);
  color: var(--accent-2);
  font-size: 0.78rem;
  font-weight: 500;
  padding: 5px 14px;
  border-radius: 999px;
  margin-bottom: 28px;
  letter-spacing: 0.03em;
}

.badge-dot {
  width: 6px;
  height: 6px;
  background: var(--green);
  border-radius: 50%;
  animation: pulse 2s infinite;
}

@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.4; }
}

.hero-title {
  font-family: var(--font-display);
  font-size: clamp(2.8rem, 6vw, 5rem);
  font-weight: 700;
  line-height: 1.08;
  letter-spacing: -0.04em;
  margin-bottom: 22px;
  color: #f1f5f9;
}

.hero-title-accent {
  background: linear-gradient(135deg, #a78bfa 0%, #7c3aed 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-subtitle {
  color: var(--text-2);
  font-size: 1.1rem;
  line-height: 1.7;
  max-width: 580px;
  margin: 0 auto 36px;
}

.br-desktop { display: inline; }

.hero-actions {
  display: flex;
  gap: 12px;
  justify-content: center;
  flex-wrap: wrap;
  margin-bottom: 28px;
}

.hero-install {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  background: rgba(255,255,255,0.03);
  border: 1px solid var(--border-2);
  border-radius: var(--radius);
  padding: 10px 16px;
  font-family: var(--font-mono);
  font-size: 0.88rem;
}

.install-prompt { color: var(--text-3); }

#installCmd { color: var(--accent-2); }

.copy-btn {
  background: none;
  border: none;
  color: var(--text-3);
  cursor: pointer;
  padding: 2px;
  display: flex;
  align-items: center;
  transition: color 0.15s;
}

.copy-btn:hover { color: var(--accent-2); }

/* ── Sections shared ─────────────────────────────────────────────────────── */

.section-label {
  font-family: var(--font-display);
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--accent-2);
  margin-bottom: 10px;
}

.section-title {
  font-family: var(--font-display);
  font-size: clamp(1.7rem, 3vw, 2.4rem);
  font-weight: 700;
  letter-spacing: -0.03em;
  line-height: 1.15;
  color: #f1f5f9;
  margin-bottom: 14px;
}

.section-sub {
  color: var(--text-2);
  font-size: 1rem;
  line-height: 1.7;
  max-width: 600px;
  margin-bottom: 48px;
}

/* ── Demo Section ─────────────────────────────────────────────────────────── */

.demo-section {
  padding: 100px 0;
  background: var(--bg-2);
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
}

.demo-tabs {
  display: flex;
  gap: 4px;
  margin-bottom: 20px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 4px;
  width: fit-content;
}

.demo-tab {
  background: none;
  border: none;
  color: var(--text-2);
  font-family: var(--font-mono);
  font-size: 0.85rem;
  padding: 7px 16px;
  border-radius: calc(var(--radius) - 2px);
  cursor: pointer;
  transition: all 0.15s;
  font-weight: 500;
}

.demo-tab:hover { color: var(--text); }

.demo-tab.active {
  background: var(--accent);
  color: #fff;
}

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

.demo-split {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
  align-items: start;
}

.demo-code-wrap,
.demo-output-wrap {
  background: #0a0a16;
  border: 1px solid var(--border-2);
  border-radius: var(--radius-lg);
  overflow: hidden;
}

.demo-file-header {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 10px 16px;
  border-bottom: 1px solid var(--border);
  background: rgba(255,255,255,0.02);
}

.demo-dots {
  display: flex;
  gap: 5px;
}

.demo-dots span {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--border-2);
}

.demo-dots span:nth-child(1) { background: #ff5f57; }
.demo-dots span:nth-child(2) { background: #febc2e; }
.demo-dots span:nth-child(3) { background: #28c840; }

.demo-filename {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--text-3);
  margin-left: 4px;
}

.demo-code {
  padding: 20px;
  overflow-x: auto;
}

.demo-code code {
  font-family: var(--font-mono);
  font-size: 0.83rem;
  line-height: 1.75;
  display: block;
}

/* Syntax colours */
.kw  { color: #a78bfa; font-weight: 500; }
.str { color: #86efac; }
.c   { color: #475569; }
.bad { color: #fca5a5; }
.good { color: #6ee7b7; }

.demo-output { padding: 16px; }

.output-line {
  display: flex;
  align-items: flex-start;
  gap: 8px;
  padding: 4px 0;
  font-family: var(--font-mono);
  font-size: 0.79rem;
  line-height: 1.6;
}

.out-icon { flex-shrink: 0; width: 16px; }
.out-icon.ok   { color: var(--green); }
.out-icon.warn { color: var(--yellow); }
.out-icon.info { color: var(--accent-2); }

.out-text { color: var(--text-2); }
.out-text strong { color: var(--text); }
.out-text code { color: var(--accent-2); }

.diff-line { padding-left: 8px; }
.diff-minus { color: #fca5a5; display: block; }
.diff-plus  { color: #86efac; display: block; }

.trace-path {
  padding-left: 28px;
  color: var(--text-3);
  font-size: 0.76rem;
  display: block;
}

.trace-arrow { color: var(--accent-2); margin: 0 3px; }

/* ── Constructs ───────────────────────────────────────────────────────────── */

.constructs-section {
  padding: 100px 0;
}

.constructs-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 14px;
}

.construct-card {
  display: block;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 24px;
  text-decoration: none;
  transition: all 0.2s;
  position: relative;
  overflow: hidden;
}

.construct-card::before {
  content: '';
  position: absolute;
  inset: 0;
  background: radial-gradient(ellipse 80% 60% at 50% 0%, rgba(124,58,237,0.08) 0%, transparent 70%);
  opacity: 0;
  transition: opacity 0.2s;
}

.construct-card:hover {
  border-color: rgba(124,58,237,0.4);
  transform: translateY(-2px);
  box-shadow: 0 12px 32px rgba(0,0,0,0.3), 0 0 0 1px rgba(124,58,237,0.15);
}

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

.construct-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 14px;
}

.construct-kw {
  font-family: var(--font-mono);
  font-size: 0.82rem;
  font-style: normal;
  color: var(--accent-2);
  background: rgba(124,58,237,0.12);
  border: 1px solid rgba(124,58,237,0.2);
  padding: 4px 10px;
  border-radius: var(--radius-sm);
}

.construct-arrow {
  color: var(--text-3);
  transition: color 0.15s, transform 0.15s;
}

.construct-card:hover .construct-arrow {
  color: var(--accent-2);
  transform: translateX(3px);
}

.construct-card h3 {
  font-family: var(--font-display);
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text);
  margin-bottom: 8px;
  letter-spacing: -0.01em;
}

.construct-card p {
  font-size: 0.85rem;
  color: var(--text-2);
  line-height: 1.6;
}

.construct-card code {
  font-family: var(--font-mono);
  font-size: 0.8em;
  color: var(--accent-2);
  background: rgba(124,58,237,0.1);
  padding: 1px 5px;
  border-radius: 3px;
}

/* ── Languages ────────────────────────────────────────────────────────────── */

.langs-section {
  padding: 80px 0;
  background: var(--bg-2);
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
}

.langs-grid { display: flex; flex-direction: column; gap: 20px; margin-bottom: 24px; }

.lang-row {
  display: flex;
  align-items: center;
  gap: 20px;
  flex-wrap: wrap;
}

.lang-status {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  font-weight: 600;
  padding: 3px 10px;
  border-radius: 999px;
  flex-shrink: 0;
  width: 52px;
  text-align: center;
}

.lang-status.stable {
  background: var(--green-dim);
  color: var(--green);
  border: 1px solid rgba(16,185,129,0.25);
}

.lang-status.beta {
  background: rgba(245,158,11,0.1);
  color: var(--yellow);
  border: 1px solid rgba(245,158,11,0.25);
}

.lang-chips { display: flex; gap: 8px; flex-wrap: wrap; }

.lang-chip {
  font-family: var(--font-display);
  font-size: 0.85rem;
  font-weight: 500;
  padding: 5px 14px;
  border-radius: var(--radius-sm);
  background: var(--surface-2);
  border: 1px solid var(--border-2);
  color: var(--text);
}

.lang-chip.dim { color: var(--text-2); }

.langs-note {
  font-size: 0.83rem;
  color: var(--text-3);
  max-width: 600px;
}

/* ── Fix Library ──────────────────────────────────────────────────────────── */

.fixlib-section {
  padding: 100px 0;
}

.fixlib-inner {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 60px;
  align-items: center;
}

.fixlib-actions { display: flex; gap: 12px; flex-wrap: wrap; }

.fixlib-file-list {
  background: var(--bg-2);
  border: 1px solid var(--border-2);
  border-radius: var(--radius-lg);
  overflow: hidden;
}

.fix-file {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 11px 16px;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--text-2);
  border-bottom: 1px solid var(--border);
  transition: background 0.1s;
}

.fix-file:last-child { border-bottom: none; }
.fix-file:hover { background: var(--surface); }

.fix-file-icon {
  width: 22px;
  height: 22px;
  border-radius: 4px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.65rem;
  font-weight: 700;
  flex-shrink: 0;
}

.fix-file-icon.ts  { background: rgba(59,130,246,0.2); color: #93c5fd; }
.fix-file-icon.py  { background: rgba(251,191,36,0.2); color: #fcd34d; }
.fix-file-icon.go  { background: rgba(16,185,129,0.2); color: #6ee7b7; }
.fix-file-icon.sec { background: rgba(244,63,94,0.15); font-size: 0.75rem; }
.fix-file-icon.mg  { background: rgba(124,58,237,0.2); color: #a78bfa; font-size: 0.8rem; }

.fix-file-badge {
  margin-left: auto;
  font-size: 0.68rem;
  font-weight: 600;
  padding: 2px 7px;
  border-radius: 999px;
}

.fix-file-badge.bug      { background: var(--red-dim); color: #fca5a5; }
.fix-file-badge.security { background: var(--red-dim); color: #fca5a5; }
.fix-file-badge.style    { background: rgba(124,58,237,0.15); color: var(--accent-2); }
.fix-file-badge.perf     { background: rgba(245,158,11,0.12); color: #fcd34d; }
.fix-file-badge.migrate  { background: var(--green-dim); color: #6ee7b7; }

/* ── Getting Started ──────────────────────────────────────────────────────── */

.start-section {
  padding: 100px 0;
  background: var(--bg-2);
  border-top: 1px solid var(--border);
}

.steps-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
  margin-bottom: 48px;
}

.step {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 28px;
}

.step-num {
  width: 32px;
  height: 32px;
  border-radius: 8px;
  background: rgba(124,58,237,0.15);
  border: 1px solid rgba(124,58,237,0.25);
  color: var(--accent-2);
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 0.85rem;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 16px;
}

.step h3 {
  font-family: var(--font-display);
  font-size: 0.95rem;
  font-weight: 600;
  margin-bottom: 12px;
  color: var(--text);
  letter-spacing: -0.01em;
}

.step-code {
  background: rgba(0,0,0,0.4);
  border: 1px solid var(--border-2);
  border-radius: var(--radius-sm);
  padding: 12px 14px;
  margin-bottom: 10px;
  overflow-x: auto;
}

.step-code code {
  font-family: var(--font-mono);
  font-size: 0.82rem;
  color: var(--accent-2);
}

.step-note {
  font-size: 0.82rem;
  color: var(--text-3);
  line-height: 1.5;
}

.step-note code {
  font-family: var(--font-mono);
  color: var(--text-2);
  font-size: 0.9em;
}

.start-links {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}

/* ── Footer ───────────────────────────────────────────────────────────────── */

.footer {
  border-top: 1px solid var(--border);
  padding: 56px 0 40px;
  background: var(--bg);
}

.footer-inner {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 60px;
  align-items: start;
}

.footer-logo { margin-bottom: 12px; display: inline-flex; }

.footer-tagline {
  font-size: 0.875rem;
  color: var(--text-2);
  margin-bottom: 4px;
}

.footer-license { font-size: 0.8rem; color: var(--text-3); }

.footer-links-grid {
  display: flex;
  gap: 56px;
}

.footer-col {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.footer-col-title {
  font-family: var(--font-display);
  font-size: 0.72rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-3);
  margin-bottom: 4px;
}

.footer-col a {
  font-size: 0.875rem;
  color: var(--text-2);
  text-decoration: none;
  transition: color 0.15s;
}

.footer-col a:hover { color: var(--accent-2); }

/* ── Responsive ───────────────────────────────────────────────────────────── */

@media (max-width: 900px) {
  .constructs-grid { grid-template-columns: repeat(2, 1fr); }
  .demo-split { grid-template-columns: 1fr; }
  .fixlib-inner { grid-template-columns: 1fr; gap: 40px; }
  .footer-inner { grid-template-columns: 1fr; gap: 40px; }
  .footer-links-grid { gap: 32px; }
  .steps-grid { grid-template-columns: 1fr; }
}

@media (max-width: 600px) {
  .nav-links { display: none; }
  .nav-mobile-toggle { display: flex; }
  .nav-links.open {
    display: flex;
    flex-direction: column;
    position: absolute;
    top: 62px;
    left: 0;
    right: 0;
    background: rgba(7,7,15,0.98);
    border-bottom: 1px solid var(--border);
    padding: 16px 24px 20px;
    gap: 16px;
    z-index: 99;
  }
  .hero-title { font-size: 2.4rem; }
  .constructs-grid { grid-template-columns: 1fr; }
  .demo-tabs { flex-wrap: wrap; }
  .br-desktop { display: none; }
  .footer-links-grid { flex-direction: column; gap: 24px; }
  .hero-actions { flex-direction: column; align-items: center; }
  .lang-row { flex-direction: column; align-items: flex-start; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation-duration: 0.01ms !important; transition-duration: 0.01ms !important; }
}