/* ==============================================================
   Professional Frontend - WCAG 2.2 + Premium Motion Infrastructure
   ============================================================== */

/* ==== Core Variables (Sophisticated Dark Palette) ==== */
:root {
  --color-bg: #0d0d0d;
  --color-surface: #1a1a1a;
  --color-primary: #ffffff;
  --color-primary-soft: rgba(255, 255, 255, 0.06);
  --color-text: #f5f5f4;
  --color-text-muted: #a0a0a6;
  --color-accent: #00d4aa;
  --color-accent-hover: #00f5c4;
  --color-border: rgba(255, 255, 255, 0.08);
  --color-shadow: rgba(0, 0, 0, 0.4);

  /* Typography */
  --font-sans: 'Inter', system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
  --fs-h1: clamp(3rem, 5vw, 3.75rem);
  --fs-h2: clamp(2rem, 4vw, 2.5rem);
  --fs-h3: clamp(1.5rem, 3vw, 1.875rem);
  --fs-body: clamp(1rem, 1.8vw, 1.125rem);
  --fs-caption: clamp(0.875rem, 1.6vw, 1rem);

  /* Spacing & Sizing */
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --radius-full: 9999px;
  --shadow-sm: 0 1px 2px var(--color-shadow);
  --shadow-md: 0 4px 12px var(--color-shadow);
  --shadow-lg: 0 12px 30px var(--color-shadow);
  --transition-fast: 0.2s ease;
  --transition-medium: 0.4s cubic-bezier(0.25, 0.46, 0.45, 0.94);
  --transition-slow: 0.8s cubic-bezier(0.05, 0.5, 0.5, 0.95);

  /* Motion */
  --ease-out: cubic-bezier(0.22, 1, 0.36, 1);
  --ease-in-out: cubic-bezier(0.42, 0, 0.58, 1);
}

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

html {
  -webkit-tap-highlight-color: transparent;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-sans);
  font-size: 100%; /* 16px base */
  line-height: 1.6;
  color: var(--color-text);
  background-color: var(--color-bg);
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

/* ==== Noise Texture (Subtle Atmosphere) ==== */
.noise-overlay {
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 1000;
  opacity: 0.03;
  background-image: url('data:image/svg+xml;charset=utf-8,<svg xmlns="http://www.w3.org/2000/svg" width="200" height="200"><filter id="noise"><feTurbulence type="fractal" baseFrequency="0.9" numOctaves="4" stitchTiles="stitch"/></filter><rect width="100%" height="100%" fill="url(#noise)"/></svg>');
}

/* ==== Custom Cursor (Subtle) ==== */
.cursor {
  position: fixed;
  width: 20px;
  height: 20px;
  pointer-events: none;
  z-index: 2000;
  mix-blend-mode: difference;
  transform: translate(-50%, -50%);
  transition: opacity 0.2s ease;
}

.cursor-dot {
  position: absolute;
  width: 6px;
  height: 6px;
  background: var(--color-accent);
  border-radius: 50%;
  mix-blend-mode: difference;
  transform: translate(-50%, -50%);
  transition: transform 0.1s ease-out, opacity 0.1s ease-out;
}

.cursor-ring {
  position: absolute;
  width: 16px;
  height: 16px;
  border: 1.5px solid var(--color-accent);
  border-radius: 50%;
  mix-blend-mode: difference;
  transform: translate(-50%, -50%);
  opacity: 0.5;
  transition: width 0.15s ease-out, opacity 0.15s ease-out;
}

/* Hover enlargement */
[data-hover]:hover + .cursor .cursor-ring,
[data-hover]:focus + .cursor .cursor-ring {
  width: 24px;
  opacity: 0.3;
}

/* Hide cursor on non-hover devices */
@media (hover: none) {
  .cursor { display: none; }
}

/* ==== Preloader ==== */
.preloader {
  position: fixed;
  inset: 0;
  background: var(--color-bg);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 9999;
  color: var(--color-text-muted);
  font-size: var(--fs-caption);
  letter-spacing: 1px;
  transition: opacity 0.6s ease;
}

.preloader-text {
  font-family: var(--font-sans);
  font-weight: 500;
}

.preloader-text {
  animation: fadeIn 0.3s ease forwards;
  opacity: 0;
  transform: translateY(4px);
}

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

/* ==== Navigation ==== */
.nav {
  position: sticky;
  top: 0;
  left: 0;
  right: 0;
  background: var(--color-surface);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  box-shadow: var(--shadow-sm);
  z-index: 1000;
  padding: 1.5rem 0;
  transition: background 0.3s ease;
}

.nav-hidden {
  transform: translateY(-100%);
}

.nav-logo {
  font-family: var(--font-sans);
  font-weight: 700;
  font-size: 1.25rem;
  color: var(--color-primary);
  text-decoration: none;
  margin-right: 2rem;
  transition: color 0.3s ease;
}

.nav-links {
  display: flex;
  gap: 2rem;
  list-style: none;
  margin: 0;
  padding: 0;
}

.nav-links a {
  text-decoration: none;
  color: var(--color-text-muted);
  font-weight: 500;
  font-size: var(--fs-body);
  position: relative;
  transition: color 0.3s ease;
}

.nav-links a::after {
  content: '';
  position: absolute;
  left: 0;
  bottom: -3px;
  width: 0;
  height: 2px;
  background: var(--color-accent);
  transition: width 0.3s ease;
}

.nav-links a:hover,
.nav-links a:focus {
  color: var(--color-accent);
}

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

/* ==== Hero Section ==== */
.hero {
  position: relative;
  min-height: 650px;
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  justify-content: center;
  padding: 2rem 1rem 4rem;
  color: var(--color-text);
}

.hero-inner {
  max-width: 720px;
}

.hero-subhead {
  font-size: var(--fs-caption);
  letter-spacing: 0.2em;
  text-transform: uppercase;
  opacity: 0.6;
  margin-bottom: 1.5rem;
  color: var(--color-text-muted);
}

.hero-title {
  font-family: var(--font-sans);
  font-weight: 800;
  font-size: var(--fs-h1);
  line-height: 1.15;
  margin: 1.5rem 0;
  color: var(--color-text);
}

.hero-title .hero-line {
  display: block;
  margin-bottom: 0.6rem;
}

.hero-title .hero-line.acc {
  color: var(--color-accent);
}

.hero-caption {
  font-size: var(--fs-body);
  color: var(--color-text-muted);
  max-width: 50ch;
  margin: 2rem 0;
  line-height: 1.7;
}

.btn-cta {
  display: inline-block;
  padding: 1rem 2rem;
  font-size: var(--fs-body);
  font-weight: 600;
  color: var(--color-primary);
  background: var(--color-accent);
  border: none;
  border-radius: var(--radius-md);
  cursor: pointer;
  position: relative;
  overflow: hidden;
  transition: transform var(--transition-fast), box-shadow var(--transition-fast);
  z-index: 1;
}

.btn-cta::before {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(90deg, transparent, rgba(255,255,255,0.15), transparent);
  opacity: 0;
  transition: opacity 0.3s ease;
}

.btn-cta:hover,
.btn-cta:focus {
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.btn-cta:hover::before,
.btn-cta:focus::before {
  opacity: 1;
}

/* ==== Features Section ==== */
.features {
  padding: 6rem 0;
  background: var(--color-surface);
}

.features-inner {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 2.5rem;
  margin: 2rem 0;
}

.feature {
  background: var(--color-bg);
  padding: 2.5rem;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
  position: relative;
  transition: transform var(--transition-medium), box-shadow var(--transition-medium);
}

.feature:hover,
.feature:focus-within {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
}

.feature-accent {
  position: absolute;
  left: 2rem;
  top: 2rem;
  width: 4px;
  height: 32px;
  background: var(--color-accent);
  border-radius: var(--radius-sm);
  transition: transform var(--transition-fast);
}

.feature:hover .feature-accent,
.feature:focus-within .feature-accent {
  transform: translateX(8px);
}

.feature-title {
  font-size: var(--fs-h3);
  color: var(--color-text);
  margin-bottom: 1rem;
}

.feature-text {
  color: var(--color-text-muted);
  line-height: 1.6;
  margin-top: 1rem;
}

/* ==== About Section ==== */
.about {
  padding: 6rem 0;
}

.about-inner {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 4rem;
  align-items: center;
}

.about-text {
  text-align: left;
}

.about-title {
  font-size: var(--fs-h2);
  margin-bottom: 1.5rem;
  color: var(--color-text);
}

.about-body {
  color: var(--color-text-muted);
  line-height: 1.7;
  max-width: 45ch;
}

.about-img {
  position: relative;
  aspect-ratio: 4/3;
  background: var(--color-bg);
  border-radius: var(--radius-lg);
  overflow: hidden;
}

/* ==== CTA Section ==== */
.cta {
  position: relative;
  padding: 6rem 0;
  text-align: center;
  background: linear-gradient(135deg, var(--color-surface), var(--color-bg));
  color: #fff;
}

.cta::before {
  content: '';
  position: absolute;
  inset: 0;
  background: url('data:image/svg+xml;charset=utf-8,<svg xmlns="http://www.w3.org/2000/svg" width="100" height="100"><rect width="100" height="100" fill="%23ffffff" opacity="0.03"/></svg>');
  pointer-events: none;
  z-index: 1;
}

.cta-inner {
  position: relative;
  max-width: 560px;
  margin: 0 auto;
}

.cta-title {
  font-size: var(--fs-h2);
  margin-bottom: 1.5rem;
}

.cta-sub {
  font-size: var(--fs-body);
  color: rgba(255, 255, 255, 0.7);
  margin: 0 auto 2rem;
  max-width: 40ch;
}

/* ==== Footer ==== */
.footer {
  padding: 4rem 0 2rem;
  background: var(--color-surface);
  text-align: center;
  color: var(--color-text-muted);
  font-size: var(--fs-caption);
  border-top: 1px solid var(--color-border);
}

.footer-inner {
  max-width: 600px;
  margin: 0 auto;
  margin-bottom: 2rem;
}

.footer-brand {
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: 1.5rem;
  font-size: 1.125rem;
}

.footer-links {
  display: flex;
  justify-content: center;
  gap: 2rem;
  margin-bottom: 1.5rem;
  flex-wrap: wrap;
}

.footer-links a {
  color: var(--color-text-muted);
  text-decoration: none;
  font-size: var(--fs-caption);
  transition: color var(--transition-fast);
}

.footer-links a:hover,
.footer-links a:focus {
  color: var(--color-accent);
}

.footer-copy {
  color: var(--color-text-muted);
}

/* ==== Scroll Indicator ==== */
.scroll-indicator {
  position: absolute;
  bottom: 2rem;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  color: rgba(255, 255, 255, 0.5);
  font-size: var(--fs-caption);
}

.scroll-line {
  width: 2px;
  height: 24px;
  background: currentColor;
  border-radius: 1px;
  animation: pulse 2s ease-in-out infinite;
}

@keyframes pulse {
  0%, 100% { opacity: 0.3; }
  50% { opacity: 0.8; }
}

/* ==== Responsive ==== */
@media (max-width: 768px) {
  .nav-links {
    gap: 1rem;
  }
  .nav-logo {
    font-size: 1.125rem;
    margin-right: 1rem;
  }
  .hero-inner {
    padding: 1rem 0;
  }
  .hero-title {
    font-size: clamp(2rem, 5vw, 2.75rem);
  }
  .features-inner {
    grid-template-columns: 1fr;
  }
  .about-inner {
    grid-template-columns: 1fr;
    gap: 3rem;
    text-align: center;
  }
  .about-img {
    margin: 0 auto;
  }
  .cta-inner {
    padding: 0 1rem;
  }
  .footer-links {
    gap: 1.5rem;
  }
}

/* ==== Accessibility ==== */
:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 2px;
}

button:focus-visible,
a:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 2px;
}

/* ==== Skip Link ==== */
.skip-link {
  position: absolute;
  top: -40px;
  left: 6px;
  background: var(--color-accent);
  color: var(--color-bg);
  padding: 8px 12px;
  text-decoration: none;
  z-index: 1001;
  border-radius: var(--radius-sm);
  font-size: var(--fs-caption);
  font-weight: 600;
}

.skip-link:focus {
  top: 6px;
}

/* ==== Forced Colors Mode (Windows HCM) ==== */
@media (forced-colors: active) {
  .noise-overlay,
  .scroll-indicator {
    display: none !important;
  }
  body {
    background: Canvas;
    color: CanvasText;
  }
  .nav {
    background: Canvas;
    color: CanvasText;
    box-shadow: none;
  }
  .nav-logo,
  .nav-links a {
    color: CanvasText !important;
  }
  .nav-links a:hover,
  .nav-links a:focus {
    color: HighlightText !important;
  }
  .hero,
  .cta {
    background: Canvas;
    color: CanvasText;
  }
  .feature {
    background: Canvas;
    border: 1px solid CanvasText;
  }
  .feature h3,
  .feature p {
    color: CanvasText;
  }
  .btn-cta {
    background: ButtonFace;
    color: ButtonText;
    border: 2px solid ButtonText;
  }
  .btn-cta:hover,
  .btn-cta:focus {
    background: ButtonFace;
    color: ButtonText;
  }
  .about-title,
  .about-body {
    color: CanvasText;
  }
}

/* ==== Reduced Motion ==== */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
  }
  .cursor,
  .cursor-dot,
  .cursor-ring {
    display: none;
  }
  .preloader-text {
    opacity: 1 !important;
    transform: none !important;
  }
  .hero-title,
  .cta-title,
  .feature-title {
    opacity: 1 !important;
    transform: none !important;
  }
  .feature,
  .feature-accent {
    transition: none !important;
  }
  .feature:hover,
  .feature:focus-within {
    transform: none !important;
    box-shadow: none !important;
  }
  .btn-cta {
    animation: none !important;
    transform: none !important;
    box-shadow: none !important;
  }
  .orb,
  .orb-2,
  .orb-3 {
    animation: none !important;
  }
  .scroll-indicator {
    display: none !important;
  }
}

/* ==== Focus Management ==== */
:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 2px;
}

button:focus-visible,
a:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 2px;
}

/* ==== Skip Link ==== */
.skip-link {
  position: absolute;
  top: -40px;
  left: 6px;
  background: var(--color-accent);
  color: var(--color-bg);
  padding: 8px 12px;
  text-decoration: none;
  z-index: 1001;
  border-radius: var(--radius-sm);
  font-size: var(--fs-caption);
  font-weight: 600;
}

.skip-link:focus {
  top: 6px;
}

/* ==== Target Size (24x24 min) ==== */
.btn-cta,
.nav-links a {
  min-height: 44px;
  min-width: 44px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

/* ==== Reduced Motion Animation Block ==== */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
  }
}