/* ============================================
   Downloader for MP3 — Design System
   Glassmorphism + Purple/Blue Gradient Theme
   ============================================ */

/* ---------- Google Font ---------- */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700;800&display=swap');

/* ---------- Custom Properties ---------- */
:root {
  /* Palette */
  --clr-bg-start: #0f0a1e;
  --clr-bg-mid: #1a1035;
  --clr-bg-end: #110d2b;
  --clr-primary: #8b5cf6;
  --clr-primary-light: #a78bfa;
  --clr-primary-dark: #6d28d9;
  --clr-accent: #6366f1;
  --clr-accent-light: #818cf8;
  --clr-surface: rgba(255, 255, 255, 0.06);
  --clr-surface-hover: rgba(255, 255, 255, 0.1);
  --clr-border: rgba(255, 255, 255, 0.1);
  --clr-border-light: rgba(255, 255, 255, 0.15);
  --clr-text: #f1f0f5;
  --clr-text-secondary: #a5a0b8;
  --clr-text-muted: #7c7893;
  --clr-success: #34d399;
  --clr-error: #f87171;
  --clr-warning: #fbbf24;

  /* Gradients */
  --grad-primary: linear-gradient(135deg, var(--clr-primary), var(--clr-accent));
  --grad-glow: linear-gradient(135deg, rgba(139, 92, 246, 0.4), rgba(99, 102, 241, 0.4));
  --grad-bg: radial-gradient(ellipse at 20% 50%, #1e1145 0%, transparent 50%),
             radial-gradient(ellipse at 80% 20%, #1a0f40 0%, transparent 50%),
             radial-gradient(ellipse at 50% 80%, #0c0826 0%, transparent 60%),
             linear-gradient(180deg, var(--clr-bg-start), var(--clr-bg-mid), var(--clr-bg-end));

  /* 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;

  /* Radii */
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-xl: 20px;
  --radius-full: 9999px;

  /* Shadows */
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.2);
  --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.25);
  --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.3);
  --shadow-glow: 0 0 30px rgba(139, 92, 246, 0.3);
  --shadow-glow-lg: 0 0 60px rgba(139, 92, 246, 0.25);
  --shadow-btn: 0 4px 20px rgba(139, 92, 246, 0.4);

  /* Typography */
  --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --text-xs: 0.75rem;
  --text-sm: 0.875rem;
  --text-base: 1rem;
  --text-lg: 1.125rem;
  --text-xl: 1.25rem;
  --text-2xl: 1.5rem;
  --text-3xl: 2rem;
  --text-4xl: 2.5rem;
  --text-5xl: 3.25rem;

  /* Transitions */
  --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
  --ease-spring: cubic-bezier(0.34, 1.56, 0.64, 1);
  --dur-fast: 200ms;
  --dur-normal: 350ms;
  --dur-slow: 500ms;

  /* Layout */
  --max-width: 1200px;
  --max-width-narrow: 800px;
}

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

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-family);
  font-size: var(--text-base);
  line-height: 1.6;
  color: var(--clr-text);
  background: var(--grad-bg);
  background-attachment: fixed;
  min-height: 100vh;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

img { max-width: 100%; height: auto; display: block; }
a { color: var(--clr-primary-light); text-decoration: none; transition: color var(--dur-fast) ease; }
a:hover { color: var(--clr-text); }
button { cursor: pointer; font-family: inherit; }
ul, ol { list-style: none; }

/* ---------- Utility ---------- */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--space-lg);
}

.container--narrow {
  max-width: var(--max-width-narrow);
}

.text-center { text-align: center; }
.text-gradient {
  background: var(--grad-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.sr-only {
  position: absolute; width: 1px; height: 1px;
  padding: 0; margin: -1px; overflow: hidden;
  clip: rect(0, 0, 0, 0); white-space: nowrap; border: 0;
}

/* ---------- Glass Card ---------- */
.glass-card {
  background: var(--clr-surface);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border: 1px solid var(--clr-border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
  transition: transform var(--dur-normal) var(--ease-out),
              box-shadow var(--dur-normal) var(--ease-out),
              background var(--dur-normal) ease;
}

.glass-card:hover {
  background: var(--clr-surface-hover);
  box-shadow: var(--shadow-lg);
  transform: translateY(-2px);
}

.glass-card--static:hover {
  transform: none;
  background: var(--clr-surface);
  box-shadow: var(--shadow-md);
}

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-sm);
  font-weight: 600;
  font-size: var(--text-base);
  padding: 0.875rem 2rem;
  border-radius: var(--radius-full);
  border: none;
  transition: all var(--dur-normal) var(--ease-out);
  position: relative;
  overflow: hidden;
  white-space: nowrap;
}

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

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 30px rgba(139, 92, 246, 0.55);
}

.btn-primary:active {
  transform: translateY(0);
  box-shadow: var(--shadow-btn);
}

.btn-primary::after {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, rgba(255,255,255,0.15), transparent);
  opacity: 0;
  transition: opacity var(--dur-fast) ease;
}

.btn-primary:hover::after { opacity: 1; }

.btn-secondary {
  background: var(--clr-surface);
  color: var(--clr-text);
  border: 1px solid var(--clr-border);
  backdrop-filter: blur(10px);
}

.btn-secondary:hover {
  background: var(--clr-surface-hover);
  border-color: var(--clr-border-light);
  transform: translateY(-1px);
}

.btn-sm {
  font-size: var(--text-sm);
  padding: 0.625rem 1.25rem;
}

.btn-download {
  background: rgba(139, 92, 246, 0.15);
  color: var(--clr-primary-light);
  border: 1px solid rgba(139, 92, 246, 0.25);
  border-radius: var(--radius-md);
  padding: 0.75rem 1.25rem;
  font-size: var(--text-sm);
  font-weight: 600;
  width: 100%;
  justify-content: space-between;
}

.btn-download:hover {
  background: rgba(139, 92, 246, 0.25);
  border-color: rgba(139, 92, 246, 0.4);
  transform: translateY(-1px);
  box-shadow: 0 4px 15px rgba(139, 92, 246, 0.2);
}

/* ---------- Section Styling ---------- */
.section {
  padding: var(--space-4xl) 0;
  position: relative;
}

.section__title {
  font-size: var(--text-3xl);
  font-weight: 700;
  margin-bottom: var(--space-md);
  letter-spacing: -0.02em;
}

.section__subtitle {
  font-size: var(--text-lg);
  color: var(--clr-text-secondary);
  max-width: 600px;
  margin: 0 auto var(--space-3xl);
}

/* ---------- Header / Nav ---------- */
.site-header {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 100;
  padding: var(--space-md) 0;
  transition: background var(--dur-normal) ease,
              backdrop-filter var(--dur-normal) ease,
              box-shadow var(--dur-normal) ease;
}

.site-header.scrolled {
  background: rgba(15, 10, 30, 0.8);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  box-shadow: 0 1px 0 var(--clr-border);
}

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

.nav__logo {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  font-weight: 700;
  font-size: var(--text-xl);
  color: var(--clr-text);
}

.nav__logo-icon {
  width: 36px;
  height: 36px;
  background: var(--grad-primary);
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.1rem;
}

.nav__links {
  display: flex;
  align-items: center;
  gap: var(--space-xl);
}

.nav__link {
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--clr-text-secondary);
  transition: color var(--dur-fast) ease;
  position: relative;
}

.nav__link::after {
  content: '';
  position: absolute;
  bottom: -4px; left: 0;
  width: 0;
  height: 2px;
  background: var(--grad-primary);
  border-radius: var(--radius-full);
  transition: width var(--dur-normal) var(--ease-out);
}

.nav__link:hover { color: var(--clr-text); }
.nav__link:hover::after { width: 100%; }

.nav__burger {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  padding: var(--space-sm);
}

.nav__burger span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--clr-text);
  border-radius: var(--radius-full);
  transition: all var(--dur-normal) var(--ease-out);
}

/* ---------- Hero ---------- */
.hero {
  padding: calc(var(--space-4xl) + 80px) 0 var(--space-4xl);
  text-align: center;
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  top: 0; left: 50%;
  transform: translateX(-50%);
  width: 800px;
  height: 800px;
  background: radial-gradient(circle, rgba(139, 92, 246, 0.12) 0%, transparent 70%);
  pointer-events: none;
}

.hero__badge {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  padding: 0.4rem 1rem;
  background: rgba(139, 92, 246, 0.12);
  border: 1px solid rgba(139, 92, 246, 0.25);
  border-radius: var(--radius-full);
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--clr-primary-light);
  margin-bottom: var(--space-xl);
}

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

@keyframes pulse-dot {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.5; transform: scale(1.5); }
}

.hero__title {
  font-size: var(--text-5xl);
  font-weight: 800;
  line-height: 1.1;
  letter-spacing: -0.03em;
  margin-bottom: var(--space-lg);
  max-width: 800px;
  margin-left: auto;
  margin-right: auto;
}

.hero__subtitle {
  font-size: var(--text-xl);
  color: var(--clr-text-secondary);
  max-width: 600px;
  margin: 0 auto var(--space-3xl);
  line-height: 1.6;
}

/* ---------- Converter ---------- */
.converter {
  max-width: 720px;
  margin: 0 auto;
  position: relative;
  z-index: 2;
}

.converter__input-group {
  display: flex;
  gap: var(--space-sm);
  padding: var(--space-sm);
  background: var(--clr-surface);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border: 1px solid var(--clr-border);
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-glow-lg);
  transition: border-color var(--dur-normal) ease,
              box-shadow var(--dur-normal) ease;
}

.converter__input-group:focus-within {
  border-color: rgba(139, 92, 246, 0.4);
  box-shadow: var(--shadow-glow-lg), 0 0 0 4px rgba(139, 92, 246, 0.1);
}

.converter__input {
  flex: 1;
  background: transparent;
  border: none;
  outline: none;
  color: var(--clr-text);
  font-size: var(--text-base);
  padding: 0.75rem 1rem;
  font-family: var(--font-family);
}

.converter__input::placeholder {
  color: var(--clr-text-muted);
}

.converter__btn {
  padding: 0.875rem 1.75rem;
  flex-shrink: 0;
}

.converter__notice {
  margin-top: var(--space-md);
  font-size: var(--text-xs);
  color: var(--clr-text-muted);
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-xs);
}

/* ---------- Error Message ---------- */
.converter__error {
  margin-top: var(--space-md);
  padding: var(--space-md) var(--space-lg);
  background: rgba(248, 113, 113, 0.1);
  border: 1px solid rgba(248, 113, 113, 0.25);
  border-radius: var(--radius-md);
  color: var(--clr-error);
  font-size: var(--text-sm);
  display: none;
  align-items: center;
  gap: var(--space-sm);
  animation: fadeSlideIn var(--dur-normal) var(--ease-out);
}

.converter__error.visible { display: flex; }

/* ---------- Progress / Loading ---------- */
.converter__progress {
  margin-top: var(--space-xl);
  display: none;
  animation: fadeSlideIn var(--dur-normal) var(--ease-out);
}

.converter__progress.visible { display: block; }

.progress-bar {
  width: 100%;
  height: 6px;
  background: rgba(255, 255, 255, 0.08);
  border-radius: var(--radius-full);
  overflow: hidden;
  margin-bottom: var(--space-md);
}

.progress-bar__fill {
  height: 100%;
  background: var(--grad-primary);
  border-radius: var(--radius-full);
  width: 0%;
  transition: width 0.3s ease;
}

.progress-info {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-sm);
  font-size: var(--text-sm);
  color: var(--clr-text-secondary);
}

.spinner {
  width: 18px; height: 18px;
  border: 2px solid rgba(139, 92, 246, 0.3);
  border-top-color: var(--clr-primary);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

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

/* ---------- Results ---------- */
.converter__results {
  margin-top: var(--space-xl);
  display: none;
  animation: fadeSlideIn var(--dur-slow) var(--ease-out);
}

.converter__results.visible { display: block; }

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

.result-info {
  display: flex;
  gap: var(--space-lg);
  margin-bottom: var(--space-xl);
}

.result-thumbnail {
  width: 160px;
  height: 90px;
  border-radius: var(--radius-md);
  overflow: hidden;
  flex-shrink: 0;
  background: rgba(255, 255, 255, 0.05);
}

.result-thumbnail img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.result-meta {
  flex: 1;
  min-width: 0;
}

.result-meta__title {
  font-size: var(--text-lg);
  font-weight: 600;
  margin-bottom: var(--space-sm);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.result-meta__detail {
  font-size: var(--text-sm);
  color: var(--clr-text-secondary);
  display: flex;
  align-items: center;
  gap: var(--space-xs);
  margin-bottom: var(--space-xs);
}

.result-downloads {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-sm);
}

.result-downloads .btn-download .quality-label {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.result-downloads .btn-download .file-size {
  font-size: var(--text-xs);
  color: var(--clr-text-muted);
  font-weight: 400;
}

.converter__reset {
  margin-top: var(--space-lg);
  text-align: center;
}

/* ---------- How it Works ---------- */
.steps-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-xl);
  position: relative;
}

.step-card {
  padding: var(--space-2xl);
  text-align: center;
  position: relative;
}

.step-card__number {
  width: 48px; height: 48px;
  background: var(--grad-primary);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: var(--text-lg);
  margin: 0 auto var(--space-lg);
  box-shadow: var(--shadow-btn);
}

.step-card__icon {
  font-size: 2rem;
  margin-bottom: var(--space-md);
}

.step-card__title {
  font-size: var(--text-xl);
  font-weight: 600;
  margin-bottom: var(--space-sm);
}

.step-card__desc {
  font-size: var(--text-sm);
  color: var(--clr-text-secondary);
  line-height: 1.6;
}

/* ---------- Quality Options ---------- */
.quality-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--space-lg);
}

.quality-card {
  padding: var(--space-xl);
  text-align: center;
  position: relative;
}

.quality-card--popular {
  border-color: rgba(139, 92, 246, 0.4);
  box-shadow: var(--shadow-glow);
}

.quality-card--popular::before {
  content: 'Popular';
  position: absolute;
  top: -10px;
  left: 50%;
  transform: translateX(-50%);
  background: var(--grad-primary);
  color: #fff;
  font-size: var(--text-xs);
  font-weight: 600;
  padding: 0.2rem 0.75rem;
  border-radius: var(--radius-full);
}

.quality-card__kbps {
  font-size: var(--text-3xl);
  font-weight: 800;
  margin-bottom: var(--space-xs);
}

.quality-card__label {
  font-size: var(--text-sm);
  color: var(--clr-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: var(--space-md);
}

.quality-card__desc {
  font-size: var(--text-sm);
  color: var(--clr-text-secondary);
  line-height: 1.5;
}

/* ---------- Benefits ---------- */
.benefits-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-xl);
}

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

.benefit-card__icon {
  width: 48px; height: 48px;
  background: rgba(139, 92, 246, 0.12);
  border: 1px solid rgba(139, 92, 246, 0.2);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.4rem;
  margin-bottom: var(--space-lg);
}

.benefit-card__title {
  font-size: var(--text-lg);
  font-weight: 600;
  margin-bottom: var(--space-sm);
}

.benefit-card__desc {
  font-size: var(--text-sm);
  color: var(--clr-text-secondary);
  line-height: 1.6;
}

/* ---------- FAQ ---------- */
.faq-list {
  max-width: 720px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
}

.faq-item {
  border-radius: var(--radius-lg);
  overflow: hidden;
}

.faq-item:hover {
  transform: none;
}

.faq-item__question {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-lg) var(--space-xl);
  background: transparent;
  border: none;
  color: var(--clr-text);
  font-size: var(--text-base);
  font-weight: 600;
  text-align: left;
  cursor: pointer;
  transition: color var(--dur-fast) ease;
}

.faq-item__question:hover { color: var(--clr-primary-light); }

.faq-item__icon {
  width: 24px; height: 24px;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  transition: transform var(--dur-normal) var(--ease-out);
  font-size: var(--text-xl);
  color: var(--clr-text-muted);
}

.faq-item.active .faq-item__icon { transform: rotate(45deg); }

.faq-item__answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height var(--dur-normal) var(--ease-out),
              padding var(--dur-normal) var(--ease-out);
}

.faq-item.active .faq-item__answer {
  max-height: 300px;
}

.faq-item__answer-inner {
  padding: 0 var(--space-xl) var(--space-lg);
  font-size: var(--text-sm);
  color: var(--clr-text-secondary);
  line-height: 1.7;
}

/* ---------- Blog Cards & Carousel ---------- */
.text-left { text-align: left; }
.blog-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(320px, 1fr)); gap: 2rem; margin-top: 2rem; }
.blog-carousel {
  display: flex;
  overflow-x: auto;
  scroll-snap-type: x mandatory;
  gap: 1.5rem;
  padding: 1rem 0 2rem;
  margin: 0 calc(-1 * var(--space-md));
  padding-inline: var(--space-md);
  -webkit-overflow-scrolling: touch;
  scrollbar-width: none;
}
.blog-carousel::-webkit-scrollbar { display: none; }
.blog-carousel .blog-card {
  flex: 0 0 320px;
  scroll-snap-align: center;
}
@media (min-width: 640px) {
  .blog-carousel { margin: 0; padding-inline: 0; }
}
.blog-card {
  overflow: hidden;
  transition: transform .3s ease, box-shadow .3s ease;
  text-decoration: none;
  color: inherit;
  display: flex;
  flex-direction: column;
}
.blog-card:hover {
  transform: translateY(-6px);
  box-shadow: 0 20px 60px rgba(139, 92, 246, .25);
}
.blog-card__img { width: 100%; height: 200px; object-fit: cover; border-radius: 16px 16px 0 0; }
.blog-card__body { padding: 1.5rem; flex: 1; display: flex; flex-direction: column; }
.blog-card__tag {
  font-size: .75rem; font-weight: 600; text-transform: uppercase;
  letter-spacing: .05em; color: var(--clr-primary-light); margin-bottom: .5rem; display: inline-block;
}
.blog-card__title {
  font-size: 1.15rem; font-weight: 700; margin-bottom: .75rem;
  line-height: 1.4; color: var(--clr-text);
}
.blog-card__excerpt { font-size: .875rem; color: var(--clr-text-secondary); line-height: 1.6; flex: 1; }
.blog-card__meta { margin-top: 1rem; display: flex; justify-content: space-between; font-size: .75rem; color: var(--clr-text-muted); }

/* ---------- Footer ---------- */
.site-footer {
  border-top: 1px solid var(--clr-border);
  padding: var(--space-3xl) 0 var(--space-xl);
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: var(--space-2xl);
  margin-bottom: var(--space-2xl);
}

.footer-brand__name {
  font-size: var(--text-xl);
  font-weight: 700;
  margin-bottom: var(--space-md);
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.footer-brand__desc {
  font-size: var(--text-sm);
  color: var(--clr-text-secondary);
  line-height: 1.6;
  max-width: 300px;
}

.footer-col__title {
  font-size: var(--text-sm);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--clr-text-muted);
  margin-bottom: var(--space-lg);
}

.footer-col__list {
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
}

.footer-col__link {
  font-size: var(--text-sm);
  color: var(--clr-text-secondary);
}

.footer-col__link:hover { color: var(--clr-text); }

.footer-bottom {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: var(--space-xl);
  border-top: 1px solid var(--clr-border);
  font-size: var(--text-xs);
  color: var(--clr-text-muted);
}

.footer-bottom__disclaimer {
  max-width: 500px;
  line-height: 1.5;
}

/* ---------- Animations ---------- */
@keyframes fadeSlideIn {
  from { opacity: 0; transform: translateY(12px); }
  to   { opacity: 1; transform: translateY(0); }
}

.fade-in {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity var(--dur-slow) var(--ease-out),
              transform var(--dur-slow) var(--ease-out);
}

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

.fade-in-delay-1 { transition-delay: 100ms; }
.fade-in-delay-2 { transition-delay: 200ms; }
.fade-in-delay-3 { transition-delay: 300ms; }
.fade-in-delay-4 { transition-delay: 400ms; }

/* ---------- Responsive ---------- */
@media (max-width: 1024px) {
  .quality-grid { grid-template-columns: repeat(2, 1fr); }
  .footer-grid { grid-template-columns: 1fr 1fr; gap: var(--space-xl); }
}

@media (max-width: 768px) {
  :root {
    --text-5xl: 2.25rem;
    --text-4xl: 2rem;
    --text-3xl: 1.5rem;
  }

  .section { padding: var(--space-3xl) 0; }

  .nav__links { display: none; }
  .nav__burger { display: flex; }

  .nav__links.open {
    display: flex;
    flex-direction: column;
    position: absolute;
    top: 100%;
    left: 0; right: 0;
    background: rgba(15, 10, 30, 0.95);
    backdrop-filter: blur(20px);
    padding: var(--space-lg);
    gap: var(--space-md);
    border-bottom: 1px solid var(--clr-border);
  }

  .hero { padding-top: calc(var(--space-3xl) + 80px); }

  .converter__input-group {
    flex-direction: column;
  }

  .converter__btn { width: 100%; }

  .steps-grid { grid-template-columns: 1fr; gap: var(--space-lg); }
  .benefits-grid { grid-template-columns: 1fr; gap: var(--space-lg); }

  .result-info { flex-direction: column; }
  .result-thumbnail { width: 100%; height: 180px; }
  .result-downloads { grid-template-columns: 1fr; }

  .footer-grid { grid-template-columns: 1fr; gap: var(--space-xl); }
  .footer-bottom { flex-direction: column; gap: var(--space-md); text-align: center; }
}

@media (max-width: 480px) {
  .container { padding: 0 var(--space-md); }
  .quality-grid { grid-template-columns: 1fr; }
}