/* ═══════════════════════════════════════════════════
   INVISIBLE AI — Design System & Styles
   Vanilla CSS · CSS Variables · Grid/Flex · Responsive
   ═══════════════════════════════════════════════════ */

/* ── CSS Variables (Design Tokens) ── */
:root {
  /* Palette */
  --color-obsidian:     #0A0C12;
  --color-obsidian-rgb: 10, 12, 18;
  --color-stealth:      #1E1E1E;
  --color-stealth-rgb:  30, 30, 30;
  --color-cyan:         #00F2FF;
  --color-cyan-rgb:     0, 242, 255;
  --color-teal:         #2A9D8F;
  --color-teal-rgb:     42, 157, 143;
  --color-surface:      #12141C;
  --color-surface-rgb:  18, 20, 28;
  --color-text:         #E0E0E6;
  --color-text-muted:   #8A8A9A;
  --color-text-dim:     #555568;
  --color-error:        #FF4D6A;
  --color-success:      #00E676;
  --color-border:       rgba(255, 255, 255, 0.06);

  /* Glass */
  --glass-bg:           rgba(18, 20, 28, 0.55);
  --glass-border:       rgba(255, 255, 255, 0.08);
  --glass-blur:         16px;

  /* Typography */
  --font-sans:  'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-mono:  'JetBrains Mono', 'Cascadia Code', 'Fira Code', monospace;
  --fs-xs:     0.75rem;
  --fs-sm:     0.875rem;
  --fs-base:   1rem;
  --fs-lg:     1.125rem;
  --fs-xl:     1.5rem;
  --fs-2xl:    2rem;
  --fs-3xl:    2.75rem;
  --fs-4xl:    3.75rem;
  --fs-hero:   clamp(2.5rem, 5vw + 1rem, 5rem);
  --lh-tight:  1.1;
  --lh-snug:   1.3;
  --lh-normal: 1.6;

  /* Spacing */
  --space-xs:  0.25rem;
  --space-sm:  0.5rem;
  --space-md:  1rem;
  --space-lg:  1.5rem;
  --space-xl:  2rem;
  --space-2xl: 3rem;
  --space-3xl: 4rem;
  --space-4xl: 6rem;
  --space-section: clamp(4rem, 8vw, 8rem);

  /* Layout */
  --max-width: 1200px;
  --nav-height: 64px;

  /* Transitions */
  --ease-out:  cubic-bezier(0.16, 1, 0.3, 1);
  --ease-snap: cubic-bezier(0.34, 1.56, 0.64, 1);
  --duration:  200ms;
  --duration-slow: 400ms;
}

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

html {
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font-sans);
  font-size: var(--fs-base);
  line-height: var(--lh-normal);
  color: var(--color-text);
  background-color: var(--color-obsidian);
  overflow-x: hidden;
  min-height: 100vh;
}

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

ul {
  list-style: none;
}

button, input {
  font-family: inherit;
  font-size: inherit;
  border: none;
  outline: none;
  background: none;
  color: inherit;
}

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

/* ── Noise Overlay ── */
.noise-overlay {
  position: fixed;
  inset: 0;
  z-index: 9999;
  pointer-events: none;
  opacity: 0.03;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 256 256' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.85' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");
  background-repeat: repeat;
  background-size: 256px 256px;
}

/* ── Scanline Overlay ── */
.scanline-overlay {
  position: fixed;
  inset: 0;
  z-index: 9998;
  pointer-events: none;
  background: repeating-linear-gradient(
    0deg,
    transparent,
    transparent 2px,
    rgba(0, 0, 0, 0.015) 2px,
    rgba(0, 0, 0, 0.015) 4px
  );
}

/* ── Glass Panel Utility ── */
.glass-panel {
  background: var(--glass-bg);
  border: 1px solid var(--glass-border);
  backdrop-filter: blur(var(--glass-blur));
  -webkit-backdrop-filter: blur(var(--glass-blur));
}

/* ════════════════════════════════════════════
   HEADER / NAV
   ════════════════════════════════════════════ */

.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  height: var(--nav-height);
  background: rgba(var(--color-obsidian-rgb), 0.8);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-border);
}

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

.logo {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  font-weight: 700;
  font-size: var(--fs-lg);
  letter-spacing: 0.08em;
}

.logo-icon {
  color: var(--color-cyan);
  font-size: var(--fs-xl);
}

.logo-text {
  color: var(--color-text);
}

.logo-accent {
  color: var(--color-cyan);
}

.nav-links {
  display: flex;
  gap: var(--space-xl);
}

.nav-links a {
  font-size: var(--fs-sm);
  font-weight: 500;
  color: var(--color-text-muted);
  letter-spacing: 0.04em;
  text-transform: uppercase;
  transition: color var(--duration) var(--ease-out);
  position: relative;
}

.nav-links a::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 0;
  height: 1px;
  background: var(--color-cyan);
  transition: width var(--duration) var(--ease-out);
}

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

.nav-links a:hover::after {
  width: 100%;
}

/* ════════════════════════════════════════════
   HERO SECTION
   ════════════════════════════════════════════ */

.hero {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 100vh;
  padding: calc(var(--nav-height) + var(--space-3xl)) var(--space-xl) var(--space-3xl);
  text-align: center;
  overflow: hidden;
}

.hero-content {
  position: relative;
  z-index: 2;
  max-width: 800px;
}

/* ── Hero Entrance Sequence ── */
.hero-tag {
  font-family: var(--font-mono);
  font-size: var(--fs-xs);
  font-weight: 500;
  letter-spacing: 0.25em;
  color: var(--color-cyan);
  margin-bottom: var(--space-lg);
  text-transform: uppercase;
  opacity: 0;
  transform: translateY(20px);
  animation: heroFadeUp 0.8s var(--ease-out) 0.2s forwards;
}

.hero-headline {
  font-size: var(--fs-hero);
  font-weight: 800;
  line-height: var(--lh-tight);
  letter-spacing: -0.02em;
  color: #FFFFFF;
  margin-bottom: var(--space-lg);
  opacity: 0;
  transform: translateY(30px);
  animation: heroFadeUp 0.9s var(--ease-out) 0.4s forwards;
}

/* Gradient text shimmer on headline */
.hero-headline::after {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: linear-gradient(90deg, transparent, rgba(var(--color-cyan-rgb), 0.06), transparent);
  animation: textShimmer 4s ease-in-out 1.5s infinite;
}

.hero-sub {
  font-size: var(--fs-lg);
  line-height: var(--lh-normal);
  color: var(--color-text-muted);
  max-width: 600px;
  margin: 0 auto var(--space-3xl);
  opacity: 0;
  transform: translateY(20px);
  animation: heroFadeUp 0.8s var(--ease-out) 0.6s forwards;
}

.countdown-container {
  display: inline-block;
  padding: var(--space-lg) var(--space-2xl);
  margin-bottom: var(--space-2xl);
  border-radius: 2px;
  opacity: 0;
  transform: translateY(20px) scale(0.98);
  animation: heroScaleUp 0.8s var(--ease-out) 0.8s forwards;
}

.cta-button {
  display: inline-flex;
  align-items: center;
  padding: var(--space-md) var(--space-2xl);
  font-size: var(--fs-sm);
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--color-obsidian);
  background: var(--color-cyan);
  border: none;
  border-radius: 2px;
  cursor: pointer;
  transition: all var(--duration) var(--ease-out);
  position: relative;
  overflow: hidden;
  opacity: 0;
  transform: translateY(20px);
  animation: heroFadeUp 0.7s var(--ease-out) 1s forwards;
}

@keyframes heroFadeUp {
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes heroScaleUp {
  to {
    opacity: 1;
    transform: translateY(0) scale(1);
  }
}

@keyframes textShimmer {
  0%, 100% { left: -100%; }
  50% { left: 100%; }
}

/* Hero glow — breathing animation */
.hero-glow {
  position: absolute;
  top: 30%;
  left: 50%;
  transform: translate(-50%, -50%);
  width: 600px;
  height: 600px;
  background: radial-gradient(circle, rgba(var(--color-cyan-rgb), 0.08) 0%, transparent 70%);
  border-radius: 50%;
  pointer-events: none;
  z-index: 1;
  animation: glowPulse 4s ease-in-out infinite;
}

@keyframes glowPulse {
  0%, 100% { opacity: 1; transform: translate(-50%, -50%) scale(1); }
  50% { opacity: 0.6; transform: translate(-50%, -50%) scale(1.15); }
}

/* ── Countdown ── */

.countdown-label {
  font-family: var(--font-mono);
  font-size: var(--fs-xs);
  font-weight: 500;
  letter-spacing: 0.3em;
  color: var(--color-text-dim);
  margin-bottom: var(--space-md);
}

.countdown {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-md);
}

.countdown-segment {
  display: flex;
  flex-direction: column;
  align-items: center;
  min-width: 64px;
}

.countdown-value {
  font-family: var(--font-mono);
  font-size: var(--fs-3xl);
  font-weight: 700;
  color: #FFFFFF;
  letter-spacing: 0.05em;
  line-height: 1;
  transition: color 0.15s;
}

.countdown-unit {
  font-family: var(--font-mono);
  font-size: var(--fs-xs);
  font-weight: 500;
  color: var(--color-text-dim);
  letter-spacing: 0.2em;
  margin-top: var(--space-xs);
}

.countdown-sep {
  font-family: var(--font-mono);
  font-size: var(--fs-2xl);
  font-weight: 300;
  color: var(--color-text-dim);
  margin-bottom: 16px;
  animation: blink 1s step-end infinite;
}

@keyframes blink {
  50% { opacity: 0.3; }
}

/* ── CTA Button ── */
.cta-button::before {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, rgba(255,255,255,0.2) 0%, transparent 50%);
  opacity: 0;
  transition: opacity var(--duration) var(--ease-out);
}

.cta-button:hover {
  transform: translateY(-2px);
  box-shadow: 0 0 40px rgba(var(--color-cyan-rgb), 0.35), 0 0 80px rgba(var(--color-cyan-rgb), 0.1);
}

.cta-button:hover::before {
  opacity: 1;
}

.cta-button:active {
  transform: translateY(0) scale(0.98);
}

/* ════════════════════════════════════════════
   FEATURES SECTION
   ════════════════════════════════════════════ */

.features {
  padding: var(--space-section) var(--space-xl);
  position: relative;
}

.section-container {
  max-width: var(--max-width);
  margin: 0 auto;
}

.section-tag {
  font-family: var(--font-mono);
  font-size: var(--fs-xs);
  font-weight: 500;
  letter-spacing: 0.25em;
  color: var(--color-cyan);
  text-transform: uppercase;
  margin-bottom: var(--space-md);
  text-align: center;
}

.section-title {
  font-size: clamp(var(--fs-2xl), 3vw + 0.5rem, var(--fs-3xl));
  font-weight: 700;
  color: #FFFFFF;
  text-align: center;
  letter-spacing: -0.01em;
  margin-bottom: var(--space-md);
}

.section-sub {
  font-size: var(--fs-lg);
  color: var(--color-text-muted);
  text-align: center;
  max-width: 560px;
  margin: 0 auto var(--space-3xl);
}

/* ── Feature Grid ── */
.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-lg);
}

.feature-card {
  padding: var(--space-2xl);
  border-radius: 2px;
  transition: all var(--duration-slow) var(--ease-out);
  position: relative;
  overflow: hidden;
}

.feature-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, rgba(var(--color-cyan-rgb), 0.4), transparent);
  opacity: 0;
  transition: opacity var(--duration-slow) var(--ease-out);
}

.feature-card:hover {
  border-color: rgba(var(--color-cyan-rgb), 0.15);
  transform: translateY(-2px);
}

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

.feature-icon {
  width: 48px;
  height: 48px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-cyan);
  margin-bottom: var(--space-lg);
  border: 1px solid rgba(var(--color-cyan-rgb), 0.15);
  border-radius: 2px;
  background: rgba(var(--color-cyan-rgb), 0.05);
  transition: all var(--duration-slow) var(--ease-out);
  position: relative;
}

.feature-icon::after {
  content: '';
  position: absolute;
  inset: -4px;
  border-radius: 4px;
  background: rgba(var(--color-cyan-rgb), 0.1);
  opacity: 0;
  transform: scale(0.8);
  transition: all var(--duration-slow) var(--ease-out);
}

.feature-card:hover .feature-icon {
  border-color: rgba(var(--color-cyan-rgb), 0.4);
  background: rgba(var(--color-cyan-rgb), 0.1);
  transform: translateY(-2px);
}

.feature-card:hover .feature-icon::after {
  opacity: 1;
  transform: scale(1);
}

.feature-title {
  font-size: var(--fs-xl);
  font-weight: 600;
  color: #FFFFFF;
  margin-bottom: var(--space-sm);
}

.feature-api {
  font-family: var(--font-mono);
  font-size: var(--fs-xs);
  color: var(--color-teal);
  letter-spacing: 0.04em;
  margin-bottom: var(--space-md);
}

.feature-desc {
  font-size: var(--fs-sm);
  line-height: var(--lh-normal);
  color: var(--color-text-muted);
}

/* ════════════════════════════════════════════
   HOW IT WORKS SECTION
   ════════════════════════════════════════════ */

.how-it-works {
  padding: var(--space-section) var(--space-xl);
  background: linear-gradient(180deg, transparent 0%, rgba(var(--color-surface-rgb), 0.4) 50%, transparent 100%);
}

/* ── Steps Grid ── */
.steps-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-lg);
  margin-bottom: var(--space-xl);
}

.step-card {
  padding: var(--space-2xl);
  border-radius: 2px;
  position: relative;
  transition: all var(--duration-slow) var(--ease-out);
}

.step-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, rgba(var(--color-cyan-rgb), 0.4), transparent);
  opacity: 0;
  transition: opacity var(--duration-slow) var(--ease-out);
}

.step-card:hover {
  border-color: rgba(var(--color-cyan-rgb), 0.15);
  transform: translateY(-2px);
}

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

.step-number {
  font-family: var(--font-mono);
  font-size: var(--fs-3xl);
  font-weight: 700;
  color: rgba(var(--color-cyan-rgb), 0.15);
  line-height: 1;
  margin-bottom: var(--space-lg);
  transition: all var(--duration-slow) var(--ease-out);
}

.step-card:hover .step-number {
  color: rgba(var(--color-cyan-rgb), 0.5);
  transform: scale(1.05);
  text-shadow: 0 0 30px rgba(var(--color-cyan-rgb), 0.2);
}

.step-title {
  font-size: var(--fs-xl);
  font-weight: 600;
  color: #FFFFFF;
  margin-bottom: var(--space-sm);
}

.step-desc {
  font-size: var(--fs-sm);
  line-height: var(--lh-normal);
  color: var(--color-text-muted);
}

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

@media (max-width: 768px) {
  .steps-grid {
    grid-template-columns: 1fr;
  }

  .step-card {
    padding: var(--space-xl);
  }
}

/* ── Code Block (unused — kept for reference) ── */
.code-block {
  max-width: 720px;
  margin: 0 auto var(--space-xl);
  border-radius: 2px;
  overflow: hidden;
}

.code-header {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-sm) var(--space-md);
  background: rgba(255, 255, 255, 0.03);
  border-bottom: 1px solid var(--color-border);
}

.code-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--color-text-dim);
}

.code-dot:first-child { background: #FF5F57; }
.code-dot:nth-child(2) { background: #FFBD2E; }
.code-dot:nth-child(3) { background: #28C840; }

.code-filename {
  font-family: var(--font-mono);
  font-size: var(--fs-xs);
  color: var(--color-text-dim);
  margin-left: auto;
}

.code-block pre {
  padding: var(--space-xl);
  overflow-x: auto;
  font-family: var(--font-mono);
  font-size: var(--fs-sm);
  line-height: 1.8;
  color: var(--color-text);
  tab-size: 4;
}

/* Syntax Highlighting */
.code-comment   { color: #5C6370; font-style: italic; }
.code-directive { color: #C678DD; }
.code-string    { color: #98C379; }
.code-type      { color: #E5C07B; }
.code-fn        { color: #61AFEF; }
.code-keyword   { color: #C678DD; }
.code-const     { color: var(--color-cyan); }

/* ── Tech Note ── */
.tech-note {
  max-width: 720px;
  margin: 0 auto;
  padding: var(--space-lg) var(--space-xl);
  border-radius: 2px;
  border-left: 2px solid var(--color-teal);
  font-size: var(--fs-sm);
  color: var(--color-text-muted);
  line-height: var(--lh-normal);
}

.tech-note strong {
  color: var(--color-teal);
}

.tech-note code {
  font-size: var(--fs-xs);
  color: var(--color-cyan);
  background: rgba(var(--color-cyan-rgb), 0.08);
  padding: 2px 6px;
  border-radius: 2px;
}

/* ════════════════════════════════════════════
   NOTIFY / CTA SECTION
   ════════════════════════════════════════════ */

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

.notify-form {
  max-width: 520px;
  margin: 0 auto;
  padding: var(--space-xl);
  border-radius: 2px;
}

.form-group {
  width: 100%;
}

.input-wrapper {
  display: flex;
  gap: 0;
  border: 1px solid var(--color-border);
  border-radius: 2px;
  overflow: hidden;
  transition: border-color var(--duration) var(--ease-out);
}

.input-wrapper:focus-within {
  border-color: rgba(var(--color-cyan-rgb), 0.4);
}

.input-wrapper input {
  flex: 1;
  padding: var(--space-md) var(--space-lg);
  background: rgba(var(--color-obsidian-rgb), 0.6);
  color: var(--color-text);
  font-size: var(--fs-sm);
}

.input-wrapper input::placeholder {
  color: var(--color-text-dim);
}

/* Submit Button */
.submit-btn {
  position: relative;
  padding: var(--space-md) var(--space-xl);
  background: var(--color-cyan);
  color: var(--color-obsidian);
  font-weight: 600;
  font-size: var(--fs-sm);
  letter-spacing: 0.04em;
  cursor: pointer;
  transition: all var(--duration) var(--ease-out);
  white-space: nowrap;
  min-width: 130px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.submit-btn:hover {
  background: #33F5FF;
}

.submit-btn:active {
  transform: scale(0.98);
}

.btn-text,
.btn-loader,
.btn-check {
  transition: all var(--duration) var(--ease-out);
}

.btn-loader,
.btn-check {
  position: absolute;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  transform: scale(0.5);
}

/* Loading State */
.submit-btn.is-loading .btn-text { opacity: 0; transform: scale(0.8); }
.submit-btn.is-loading .btn-loader {
  opacity: 1;
  transform: scale(1);
  animation: spin 0.8s linear infinite;
}

/* Success State */
.submit-btn.is-success {
  background: var(--color-success);
}
.submit-btn.is-success .btn-text { opacity: 0; transform: scale(0.8); }
.submit-btn.is-success .btn-check {
  opacity: 1;
  transform: scale(1);
  animation: popIn var(--duration-slow) var(--ease-snap);
}

@keyframes spin {
  to { transform: scale(1) rotate(360deg); }
}

@keyframes popIn {
  0%   { transform: scale(0.3); opacity: 0; }
  60%  { transform: scale(1.1); }
  100% { transform: scale(1); opacity: 1; }
}

/* Form Error */
.form-error {
  font-size: var(--fs-xs);
  color: var(--color-error);
  margin-top: var(--space-sm);
  min-height: 1.2em;
  font-family: var(--font-mono);
  letter-spacing: 0.02em;
  transition: opacity var(--duration) var(--ease-out);
}

.input-wrapper.has-error {
  border-color: var(--color-error);
}

/* ════════════════════════════════════════════
   FOOTER
   ════════════════════════════════════════════ */

.site-footer {
  padding: var(--space-2xl) var(--space-xl);
  border-top: 1px solid var(--color-border);
  text-align: center;
}

.footer-container {
  max-width: var(--max-width);
  margin: 0 auto;
}

.footer-copy {
  font-size: var(--fs-sm);
  color: var(--color-text-dim);
  margin-bottom: var(--space-xs);
}

.footer-note {
  font-family: var(--font-mono);
  font-size: var(--fs-xs);
  color: var(--color-text-dim);
  letter-spacing: 0.1em;
  opacity: 0.6;
}

/* ════════════════════════════════════════════
   SCROLL ANIMATIONS (Intersection Observer)
   ════════════════════════════════════════════ */

.fade-in-up {
  opacity: 0;
  transform: translateY(32px);
  transition: opacity 0.7s var(--ease-out), transform 0.7s var(--ease-out);
}

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

.fade-in-left {
  opacity: 0;
  transform: translateX(-32px);
  transition: opacity 0.7s var(--ease-out), transform 0.7s var(--ease-out);
}

.fade-in-left.is-visible {
  opacity: 1;
  transform: translateX(0);
}

.fade-in-right {
  opacity: 0;
  transform: translateX(32px);
  transition: opacity 0.7s var(--ease-out), transform 0.7s var(--ease-out);
}

.fade-in-right.is-visible {
  opacity: 1;
  transform: translateX(0);
}

.scale-in {
  opacity: 0;
  transform: scale(0.92);
  transition: opacity 0.6s var(--ease-out), transform 0.6s var(--ease-out);
}

.scale-in.is-visible {
  opacity: 1;
  transform: scale(1);
}

/* ── Floating particles canvas ── */
.particles-canvas {
  position: fixed;
  inset: 0;
  z-index: 0;
  pointer-events: none;
}

/* ── Horizontal divider line animation ── */
.section-divider {
  width: 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, rgba(var(--color-cyan-rgb), 0.3), transparent);
  margin: 0 auto;
  transition: width 1s var(--ease-out);
}

.section-divider.is-visible {
  width: 120px;
}

/* ── Feature card glow on hover ── */
.feature-card::after {
  content: '';
  position: absolute;
  inset: 0;
  background: radial-gradient(circle at var(--mouse-x, 50%) var(--mouse-y, 50%), rgba(var(--color-cyan-rgb), 0.06) 0%, transparent 60%);
  opacity: 0;
  transition: opacity var(--duration-slow) var(--ease-out);
  pointer-events: none;
}

.feature-card:hover::after {
  opacity: 1;
}

/* ── Step card connector line ── */
.step-card::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 50%;
  width: 0;
  height: 2px;
  background: var(--color-cyan);
  transform: translateX(-50%);
  transition: width var(--duration-slow) var(--ease-out);
}

.step-card:hover::after {
  width: 40%;
}

/* ── Logo icon pulse ── */
.logo-icon {
  animation: logoPulse 3s ease-in-out infinite;
}

@keyframes logoPulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.6; }
}

/* ── Nav appear on load ── */
.site-header {
  animation: navSlideDown 0.6s var(--ease-out) forwards;
}

@keyframes navSlideDown {
  from {
    opacity: 0;
    transform: translateY(-100%);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* ── Reduced motion ── */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
  .hero-tag, .hero-headline, .hero-sub, .countdown-container, .cta-button {
    opacity: 1;
    transform: none;
  }
}

/* ════════════════════════════════════════════
   RESPONSIVE
   ════════════════════════════════════════════ */

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

/* Mobile */
@media (max-width: 768px) {
  .nav-links {
    display: none;
  }

  .hero-headline {
    font-size: clamp(2rem, 8vw, 3.5rem);
  }

  .hero-sub br {
    display: none;
  }

  .countdown {
    gap: var(--space-sm);
  }

  .countdown-value {
    font-size: var(--fs-2xl);
  }

  .countdown-segment {
    min-width: 48px;
  }

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

  .feature-card {
    padding: var(--space-xl);
  }

  .code-block pre {
    font-size: var(--fs-xs);
    padding: var(--space-md);
  }

  .input-wrapper {
    flex-direction: column;
  }

  .submit-btn {
    padding: var(--space-md);
  }
}

/* Small phones */
@media (max-width: 420px) {
  .countdown-sep {
    font-size: var(--fs-lg);
    margin-bottom: 12px;
  }

  .countdown-value {
    font-size: var(--fs-xl);
  }

  .countdown-segment {
    min-width: 40px;
  }
}

/* 4K+ monitors */
@media (min-width: 2560px) {
  :root {
    --max-width: 1400px;
    --fs-base: 1.125rem;
  }

  .hero-content {
    max-width: 960px;
  }
}