/* ═══════════════════════════════════════════════
   AudioBook Boss™ — "The Private Library"
   Warm espresso tones, copper accents, literary serif
   ═══════════════════════════════════════════════ */

:root {
  /* Palette — lamplit library */
  --bg-deep: #0d0b08;
  --bg-surface: #161210;
  --bg-card: #1e1914;
  --bg-card-hover: #262019;

  --accent: #c4884e;
  --accent-bright: #d9a066;
  --accent-dim: #8b6038;

  --text-hero: #f5ede3;
  --text-primary: #e2d8ca;
  --text-secondary: #a89580;
  --text-muted: #6b5d4e;

  --border-subtle: rgba(196, 136, 78, 0.12);
  --border-hover: rgba(196, 136, 78, 0.3);

  --serif: "Cormorant Garamond", "Georgia", serif;
  --sans: "Outfit", system-ui, sans-serif;

  --ease-out-expo: cubic-bezier(0.16, 1, 0.3, 1);
  --ease-out-quart: cubic-bezier(0.25, 1, 0.5, 1);
}

/* ── Reset & Base ── */

*,
*::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(--sans);
  font-weight: 400;
  color: var(--text-primary);
  background: var(--bg-deep);
  line-height: 1.7;
  overflow-x: hidden;
}

/* ── Grain overlay — analog warmth ── */

body::before {
  content: "";
  position: fixed;
  inset: 0;
  z-index: 9999;
  pointer-events: none;
  opacity: 0.035;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 512 512' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='g'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.75' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23g)'/%3E%3C/svg%3E");
  background-repeat: repeat;
  background-size: 256px 256px;
}

/* ── Ambient light — warm gradient mesh ── */

.ambient-light {
  position: fixed;
  inset: 0;
  z-index: -1;
  pointer-events: none;
  background:
    radial-gradient(ellipse 80% 50% at 20% 10%, rgba(196, 136, 78, 0.06) 0%, transparent 60%),
    radial-gradient(ellipse 60% 60% at 80% 80%, rgba(139, 96, 56, 0.04) 0%, transparent 50%),
    radial-gradient(ellipse 40% 40% at 50% 50%, rgba(100, 70, 40, 0.03) 0%, transparent 40%);
}

/* ── Typography ── */

h1, h2, h3 {
  font-family: var(--serif);
  font-weight: 700;
  line-height: 1.1;
}

a {
  color: var(--accent);
  text-decoration: none;
  transition: color 0.3s var(--ease-out-quart);
}

a:hover {
  color: var(--accent-bright);
}

/* ── Layout ── */

.container {
  width: min(90%, 1080px);
  margin-inline: auto;
}

section {
  padding: 6rem 0;
}

/* ── Decorative rule ── */

.rule {
  border: none;
  height: 1px;
  background: linear-gradient(
    90deg,
    transparent 0%,
    var(--accent-dim) 30%,
    var(--accent) 50%,
    var(--accent-dim) 70%,
    transparent 100%
  );
  opacity: 0.3;
  margin: 0;
}

/* ── Navigation ── */

nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  padding: 1.25rem 0;
  background: linear-gradient(to bottom, var(--bg-deep) 60%, transparent);
  transition: backdrop-filter 0.4s;
}

nav.scrolled {
  backdrop-filter: blur(12px) saturate(1.2);
  -webkit-backdrop-filter: blur(12px) saturate(1.2);
  background: rgba(13, 11, 8, 0.85);
}

.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-brand {
  font-family: var(--serif);
  font-size: 1.3rem;
  font-weight: 700;
  color: var(--text-hero);
  letter-spacing: 0.02em;
}

.nav-brand span {
  color: var(--accent);
}

.nav-links {
  display: flex;
  gap: 2rem;
  align-items: center;
  list-style: none;
}

.nav-links a {
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--text-secondary);
  letter-spacing: 0.04em;
  text-transform: uppercase;
  transition: color 0.3s;
}

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

.github-link {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.5rem 1.1rem;
  border: 1px solid var(--border-hover);
  border-radius: 6px;
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--accent) !important;
  transition: all 0.3s var(--ease-out-quart);
}

.github-link:hover {
  background: rgba(196, 136, 78, 0.08);
  border-color: var(--accent);
  color: var(--accent-bright) !important;
  transform: translateY(-1px);
}

.github-link svg {
  width: 18px;
  height: 18px;
  fill: currentColor;
}

/* ── Hero ── */

.hero {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  text-align: center;
  padding: 8rem 0 6rem;
  position: relative;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.4rem 1rem;
  border: 1px solid var(--border-subtle);
  border-radius: 100px;
  font-size: 0.78rem;
  font-weight: 500;
  color: var(--text-muted);
  letter-spacing: 0.06em;
  text-transform: uppercase;
  margin-bottom: 2.5rem;
}

.hero-badge .dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--accent);
  animation: pulse-dot 2.5s ease-in-out infinite;
}

@keyframes pulse-dot {
  0%, 100% { opacity: 0.4; transform: scale(1); }
  50% { opacity: 1; transform: scale(1.3); }
}

.hero h1 {
  font-size: clamp(3.2rem, 8vw, 7.5rem);
  color: var(--text-hero);
  letter-spacing: -0.02em;
  margin-bottom: 0.15em;
}

.hero h1 .tm {
  font-size: 0.35em;
  vertical-align: super;
  color: var(--accent-dim);
  font-weight: 400;
}

.hero-tagline {
  font-family: var(--serif);
  font-size: clamp(1.15rem, 2.5vw, 1.55rem);
  font-weight: 400;
  font-style: italic;
  color: var(--text-secondary);
  max-width: 38ch;
  margin: 0 auto 3rem;
  line-height: 1.5;
}

.hero-cta {
  display: inline-flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.9rem 2rem;
  background: linear-gradient(135deg, var(--accent) 0%, var(--accent-dim) 100%);
  color: var(--bg-deep);
  font-family: var(--sans);
  font-size: 0.9rem;
  font-weight: 600;
  letter-spacing: 0.03em;
  border-radius: 8px;
  border: none;
  cursor: pointer;
  text-decoration: none;
  transition: all 0.35s var(--ease-out-expo);
  box-shadow: 0 4px 24px rgba(196, 136, 78, 0.2);
}

.hero-cta:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 32px rgba(196, 136, 78, 0.3);
  color: var(--bg-deep);
}

.hero-cta svg {
  width: 20px;
  height: 20px;
  fill: currentColor;
}

.hero-scroll {
  position: absolute;
  bottom: 2.5rem;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.5rem;
  color: var(--text-muted);
  font-size: 0.7rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  animation: float-hint 3s ease-in-out infinite;
}

.hero-scroll .chevron {
  width: 20px;
  height: 20px;
  border-right: 1.5px solid var(--text-muted);
  border-bottom: 1.5px solid var(--text-muted);
  transform: rotate(45deg);
}

@keyframes float-hint {
  0%, 100% { opacity: 0.4; transform: translateX(-50%) translateY(0); }
  50% { opacity: 0.7; transform: translateX(-50%) translateY(6px); }
}

/* ── Features ── */

.features-header {
  text-align: center;
  margin-bottom: 4rem;
}

.features-header .label {
  font-family: var(--sans);
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 1rem;
  display: block;
}

.features-header h2 {
  font-size: clamp(2rem, 4vw, 3.2rem);
  color: var(--text-hero);
  letter-spacing: -0.01em;
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1.5rem;
}

.feature-card {
  padding: 2.2rem;
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: 12px;
  transition: all 0.4s var(--ease-out-expo);
  position: relative;
  overflow: hidden;
}

.feature-card::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--accent-dim), transparent);
  opacity: 0;
  transition: opacity 0.4s;
}

.feature-card:hover {
  background: var(--bg-card-hover);
  border-color: var(--border-hover);
  transform: translateY(-2px);
}

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

.feature-icon {
  width: 44px;
  height: 44px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 10px;
  background: rgba(196, 136, 78, 0.08);
  border: 1px solid rgba(196, 136, 78, 0.15);
  margin-bottom: 1.4rem;
  color: var(--accent);
}

.feature-icon svg {
  width: 22px;
  height: 22px;
  stroke: currentColor;
  fill: none;
  stroke-width: 1.8;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.feature-card h3 {
  font-size: 1.35rem;
  color: var(--text-hero);
  margin-bottom: 0.6rem;
  font-weight: 600;
}

.feature-card p {
  font-size: 0.92rem;
  color: var(--text-secondary);
  line-height: 1.65;
}

/* ── Built With ── */

.built-with {
  text-align: center;
}

.built-with .label {
  font-family: var(--sans);
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 1rem;
  display: block;
}

.built-with h2 {
  font-size: clamp(1.8rem, 3.5vw, 2.8rem);
  color: var(--text-hero);
  margin-bottom: 1.5rem;
}

.built-with > p {
  font-size: 1.05rem;
  color: var(--text-secondary);
  max-width: 52ch;
  margin: 0 auto 3.5rem;
  line-height: 1.7;
}

.tech-stack {
  display: flex;
  justify-content: center;
  gap: 1.5rem;
  flex-wrap: wrap;
}

.tech-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  padding: 0.7rem 1.4rem;
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: 8px;
  font-size: 0.88rem;
  font-weight: 500;
  color: var(--text-primary);
  transition: all 0.3s var(--ease-out-quart);
}

.tech-badge:hover {
  border-color: var(--border-hover);
  transform: translateY(-1px);
}

.tech-badge .tech-color {
  width: 8px;
  height: 8px;
  border-radius: 50%;
}

.tech-badge .tech-color.rust { background: #dea584; }
.tech-badge .tech-color.tauri { background: #ffc131; }
.tech-badge .tech-color.svelte { background: #ff3e00; }
.tech-badge .tech-color.ffmpeg { background: #5cb85c; }

/* ── Open Source ── */

.open-source {
  text-align: center;
}

.open-source-card {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: 16px;
  padding: 3.5rem 2.5rem;
  max-width: 640px;
  margin: 0 auto;
  position: relative;
  overflow: hidden;
}

.open-source-card::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 1px;
  background: linear-gradient(90deg, transparent 10%, var(--accent) 50%, transparent 90%);
  opacity: 0.4;
}

.open-source-card h2 {
  font-size: clamp(1.6rem, 3vw, 2.4rem);
  color: var(--text-hero);
  margin-bottom: 1rem;
}

.open-source-card p {
  font-size: 1rem;
  color: var(--text-secondary);
  max-width: 44ch;
  margin: 0 auto 2rem;
  line-height: 1.7;
}

.license-note {
  font-size: 0.82rem;
  color: var(--text-muted);
  margin-top: 1.5rem;
}

/* ── Footer ── */

footer {
  padding: 3rem 0;
  text-align: center;
}

.footer-brand {
  font-family: var(--serif);
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--text-secondary);
  margin-bottom: 0.6rem;
}

.footer-legal {
  font-size: 0.78rem;
  color: var(--text-muted);
  line-height: 1.8;
}

/* ── Scroll reveal animations ── */

.reveal {
  opacity: 0;
  transform: translateY(28px);
  transition: opacity 0.8s var(--ease-out-expo), transform 0.8s var(--ease-out-expo);
}

.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

.reveal-delay-1 { transition-delay: 0.1s; }
.reveal-delay-2 { transition-delay: 0.2s; }
.reveal-delay-3 { transition-delay: 0.3s; }
.reveal-delay-4 { transition-delay: 0.4s; }

/* ── Responsive ── */

@media (max-width: 768px) {
  section {
    padding: 4rem 0;
  }

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

  .nav-links .nav-text-link {
    display: none;
  }

  .hero {
    padding: 7rem 0 5rem;
  }

  .hero-scroll {
    display: none;
  }

  .tech-stack {
    gap: 0.8rem;
  }

  .open-source-card {
    padding: 2.5rem 1.5rem;
  }
}

@media (max-width: 480px) {
  .hero h1 {
    font-size: 2.8rem;
  }

  .hero-tagline {
    font-size: 1.05rem;
  }

  .feature-card {
    padding: 1.6rem;
  }
}