/* ══════════════════════════════════════════════════════════════════
   COLOR THEORY SYSTEM
   Primary:     #1DB954  — Spotify green (hue 141)
   Triadic 1:   #541DB9  — deep violet   (hue 261, +120°)
   Triadic 2:   #B9541D  — ember orange  (hue 21,  +240°) — used only for
                           warm accents / hover states
   Analogous:   #1DB990  — teal          (hue 161, +20°)
   Neutral:     #0a0a0f  — near-black with cool blue-tint (hue 240, 5% sat)
   Surface:     Layered neutrals — #111118, #18181f, #1e1e28
   
   Rationale:
   - Green carries "success / download / go" — primary CTA
   - Violet provides depth on background glow — doesn't compete
   - All text contrast ratios ≥ 4.5:1 (WCAG AA) on their respective surfaces
   ══════════════════════════════════════════════════════════════════ */

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

/* ── Design Tokens ──────────────────────────────────────────────────── */
:root {
  /* Background layers */
  --bg-base:          #0a0a0f;
  --bg-surface:       #111118;
  --bg-raised:        #18181f;
  --bg-elevated:      #1e1e28;

  /* Primary accent — Spotify green */
  --green-500:        #1DB954;
  --green-400:        #1ed760;
  --green-300:        #4aea84;
  --green-muted:      rgba(29, 185, 84, 0.12);
  --green-border:     rgba(29, 185, 84, 0.25);
  --green-glow:       rgba(29, 185, 84, 0.18);

  /* Triadic violet — depth / glow background */
  --violet-600:       #3a1480;
  --violet-500:       #541DB9;
  --violet-400:       #7B52D4;
  --violet-muted:     rgba(84, 29, 185, 0.10);
  --violet-glow:      rgba(84, 29, 185, 0.20);

  /* Neutral text */
  --text-primary:     #f0f0f5;
  --text-secondary:   #a0a0b8;
  --text-muted:       #60607a;
  --text-on-accent:   #000000;

  /* Semantic */
  --color-error:      #f06070;
  --color-error-bg:   rgba(240, 96, 112, 0.10);
  --color-error-border: rgba(240, 96, 112, 0.25);
  --color-success:    var(--green-500);
  --color-success-bg: var(--green-muted);

  /* Borders */
  --border-subtle:    rgba(255, 255, 255, 0.06);
  --border-default:   rgba(255, 255, 255, 0.10);
  --border-hover:     rgba(255, 255, 255, 0.18);

  /* Radii */
  --radius-sm:  6px;
  --radius-md:  14px;
  --radius-lg:  20px;
  --radius-xl:  28px;
  --radius-pill: 999px;

  /* Shadows */
  --shadow-card:  0 0 0 1px var(--border-subtle),
                  0 8px 32px rgba(0, 0, 0, 0.55),
                  0 2px 8px rgba(0, 0, 0, 0.30);
  --shadow-input: 0 0 0 3px var(--green-muted);
  --shadow-btn:   0 4px 24px rgba(29, 185, 84, 0.35);

  /* Typography */
  --font-sans:  'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;

  /* Transitions */
  --t-fast:   120ms ease;
  --t-base:   220ms ease;
  --t-slow:   380ms ease;
}

/* ── Base ───────────────────────────────────────────────────────────── */
html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  background-color: var(--bg-base);
  color: var(--text-primary);
  font-family: var(--font-sans);
  line-height: 1.6;
  min-height: 100vh;
}

img, svg { display: block; }

/* ── Accessibility ──────────────────────────────────────────────────── */
.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;
}

.skip-link {
  position: absolute;
  top: -100%;
  left: 1rem;
  background: var(--green-500);
  color: var(--text-on-accent);
  font-weight: 700;
  padding: 0.5rem 1rem;
  border-radius: 0 0 var(--radius-sm) var(--radius-sm);
  z-index: 9999;
  transition: top var(--t-fast);
  text-decoration: none;
}
.skip-link:focus { top: 0; }

:focus-visible {
  outline: 2px solid var(--green-500);
  outline-offset: 3px;
  border-radius: var(--radius-sm);
}

/* ── Layout ─────────────────────────────────────────────────────────── */
.page-wrapper {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

/* ── Header ─────────────────────────────────────────────────────────── */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background-color: rgba(10, 10, 15, 0.85);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border-subtle);
}

.header-inner {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 2rem;
  height: 60px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.logo {
  display: flex;
  align-items: center;
  gap: 0.625rem;
  text-decoration: none;
  color: var(--text-primary);
}

.logo-text {
  font-size: 1.125rem;
  font-weight: 800;
  letter-spacing: -0.02em;
}

.logo-icon {
  line-height: 0;
  filter: drop-shadow(0 0 8px var(--green-glow));
}

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

.nav-link {
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-secondary);
  text-decoration: none;
  transition: color var(--t-fast);
}
.nav-link:hover { color: var(--text-primary); }

/* ── Hero ───────────────────────────────────────────────────────────── */
.hero-section {
  position: relative;
  padding: 5rem 2rem 0;
  text-align: center;
  overflow: hidden;
}

/* Dual-tone ambient glow — green (primary) + violet (triadic depth) */
.hero-glow {
  position: absolute;
  top: -120px;
  left: 50%;
  transform: translateX(-50%);
  width: 800px;
  height: 500px;
  background: radial-gradient(
    ellipse at 40% 40%,
    var(--violet-glow) 0%,
    transparent 60%
  ),
  radial-gradient(
    ellipse at 65% 35%,
    var(--green-glow) 0%,
    transparent 55%
  );
  pointer-events: none;
  z-index: 0;
}

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

.badge {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  background: var(--bg-raised);
  border: 1px solid var(--border-default);
  border-radius: var(--radius-pill);
  padding: 0.375rem 1rem;
  font-size: 0.8125rem;
  font-weight: 500;
  color: var(--text-secondary);
  margin-bottom: 1.5rem;
  letter-spacing: 0.01em;
}

.badge-dot {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--green-500);
  box-shadow: 0 0 6px var(--green-500);
  animation: pulse-dot 2.4s ease-in-out infinite;
}

@keyframes pulse-dot {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.6; transform: scale(0.85); }
}

.hero-title {
  font-size: clamp(2rem, 5vw, 3.25rem);
  font-weight: 900;
  letter-spacing: -0.035em;
  line-height: 1.1;
  margin-bottom: 1.25rem;
  color: var(--text-primary);
}

.hero-accent {
  /* Triadic gradient — green to violet gives the color theory payoff */
  background: linear-gradient(90deg, var(--green-400) 0%, var(--violet-400) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-subtitle {
  font-size: clamp(1rem, 2vw, 1.125rem);
  color: var(--text-secondary);
  max-width: 520px;
  margin: 0 auto 3rem;
  line-height: 1.65;
}

/* ── Main / Card ────────────────────────────────────────────────────── */
.main-content {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 0 1rem 4rem;
}

.card {
  width: 100%;
  max-width: 540px;
  background: var(--bg-surface);
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-card);
  padding: 2.5rem;
  position: relative;
  /* Subtle inner green-tint top border via gradient */
  background-image: linear-gradient(
    180deg,
    rgba(29, 185, 84, 0.05) 0%,
    transparent 50%
  );
}

/* ── Form ───────────────────────────────────────────────────────────── */
.form-group {
  margin-bottom: 1.25rem;
}

.form-row {
  display: flex;
  gap: 1rem;
  margin-bottom: 1.25rem;
}

.form-group--half {
  flex: 1;
  margin-bottom: 0;
}

.input-label {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  font-size: 0.75rem;
  font-weight: 700;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-bottom: 0.5rem;
}

/* URL input with icon */
.input-wrapper {
  position: relative;
}

.input-icon {
  position: absolute;
  left: 0.9rem;
  top: 50%;
  transform: translateY(-50%);
  color: var(--text-muted);
  pointer-events: none;
  line-height: 0;
  transition: color var(--t-fast);
}

.input-url {
  width: 100%;
  background: var(--bg-raised);
  border: 1px solid var(--border-default);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  font-family: var(--font-sans);
  font-size: 0.9375rem;
  padding: 0.875rem 1rem 0.875rem 2.75rem;
  transition: border-color var(--t-fast), box-shadow var(--t-fast);
}

.input-url::placeholder { color: var(--text-muted); }

.input-url:hover { border-color: var(--border-hover); }

.input-url:hover + .input-icon,
.input-url:focus + .input-icon { color: var(--green-500); }

.input-url:focus {
  outline: none;
  border-color: var(--green-500);
  box-shadow: var(--shadow-input);
}

.input-url.input--error {
  border-color: var(--color-error);
  box-shadow: 0 0 0 3px var(--color-error-bg);
}

.input-hint {
  display: block;
  margin-top: 0.4rem;
  font-size: 0.8rem;
  color: var(--text-muted);
}

/* Select */
.select-wrapper {
  position: relative;
}

.select-arrow {
  position: absolute;
  right: 0.9rem;
  top: 50%;
  transform: translateY(-50%);
  color: var(--text-muted);
  pointer-events: none;
  line-height: 0;
}

.input-select {
  width: 100%;
  background: var(--bg-raised);
  border: 1px solid var(--border-default);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  font-family: var(--font-sans);
  font-size: 0.9375rem;
  padding: 0.75rem 2.5rem 0.75rem 1rem;
  cursor: pointer;
  appearance: none;
  transition: border-color var(--t-fast), box-shadow var(--t-fast);
}

.input-select:hover { border-color: var(--border-hover); }

.input-select:focus {
  outline: none;
  border-color: var(--green-500);
  box-shadow: var(--shadow-input);
}

.input-select:disabled {
  opacity: 0.4;
  cursor: not-allowed;
}

.input-select option {
  background: var(--bg-elevated);
  color: var(--text-primary);
}

.bitrate-note {
  font-size: 0.7rem;
  font-weight: 400;
  color: var(--green-500);
  text-transform: none;
  letter-spacing: 0;
}

/* ── Buttons ────────────────────────────────────────────────────────── */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  border: none;
  border-radius: var(--radius-md);
  cursor: pointer;
  font-family: var(--font-sans);
  font-size: 1rem;
  font-weight: 700;
  letter-spacing: 0.01em;
  padding: 0.9rem 1.5rem;
  text-decoration: none;
  transition: background-color var(--t-fast),
              box-shadow var(--t-fast),
              transform var(--t-fast),
              opacity var(--t-fast);
  user-select: none;
  white-space: nowrap;
}

.btn:active:not(:disabled) { transform: scale(0.97); }

.btn-icon { line-height: 0; flex-shrink: 0; }

/* Primary — green CTA */
.btn--primary {
  background: var(--green-500);
  color: var(--text-on-accent);
  width: 100%;
  box-shadow: 0 2px 12px rgba(29, 185, 84, 0.22);
}

.btn--primary:hover:not(:disabled) {
  background: var(--green-400);
  box-shadow: var(--shadow-btn);
}

.btn--primary:disabled {
  opacity: 0.55;
  cursor: not-allowed;
  box-shadow: none;
}

/* Success — same green, slightly elevated */
.btn--success {
  background: var(--green-500);
  color: var(--text-on-accent);
  width: 100%;
  box-shadow: 0 2px 12px rgba(29, 185, 84, 0.22);
}

.btn--success:hover {
  background: var(--green-400);
  box-shadow: var(--shadow-btn);
}

/* Ghost */
.btn--ghost {
  background: transparent;
  border: 1px solid var(--border-default);
  color: var(--text-secondary);
  width: 100%;
}

.btn--ghost:hover {
  border-color: var(--green-border);
  color: var(--green-400);
  background: var(--green-muted);
}

/* ── Progress Section ───────────────────────────────────────────────── */
.progress-section {
  margin-top: 1.75rem;
  padding-top: 1.75rem;
  border-top: 1px solid var(--border-subtle);
}

.progress-section[hidden] { display: none; }

.progress-header {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin-bottom: 0.875rem;
}

.status-text {
  font-size: 0.9rem;
  color: var(--text-secondary);
  flex: 1;
}

.progress-hint {
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-top: 0.625rem;
}

/* Spinner */
.spinner {
  display: inline-block;
  width: 20px;
  height: 20px;
  border: 2.5px solid var(--border-default);
  border-top-color: var(--green-500);
  border-radius: 50%;
  flex-shrink: 0;
  animation: spin 700ms linear infinite;
}

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

/* Progress bar */
.progress-bar-track {
  width: 100%;
  height: 5px;
  background: var(--bg-elevated);
  border-radius: var(--radius-pill);
  overflow: hidden;
}

.progress-bar-fill {
  height: 100%;
  width: 0%;
  background: linear-gradient(90deg, var(--green-500), var(--green-300));
  border-radius: var(--radius-pill);
  transition: width 350ms ease-out;
}

.progress-bar-fill--indeterminate {
  width: 40% !important;
  animation: indeterminate 1.4s ease-in-out infinite;
}

@keyframes indeterminate {
  0%   { transform: translateX(-100%); }
  100% { transform: translateX(350%); }
}

/* ── Result Section ─────────────────────────────────────────────────── */
.result-section {
  margin-top: 1.75rem;
  padding: 1.5rem;
  background: var(--color-success-bg);
  border: 1px solid var(--green-border);
  border-radius: var(--radius-md);
  text-align: center;
}

.result-section[hidden] { display: none; }

.result-icon-wrap {
  width: 52px;
  height: 52px;
  border-radius: 50%;
  background: var(--green-muted);
  border: 1px solid var(--green-border);
  color: var(--green-500);
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 1rem;
}

.result-filename {
  font-size: 0.875rem;
  color: var(--text-secondary);
  word-break: break-all;
  margin-bottom: 1.25rem;
  padding: 0 0.5rem;
}

/* ── Error Section ──────────────────────────────────────────────────── */
.error-section {
  margin-top: 1.75rem;
  padding: 1.5rem;
  background: var(--color-error-bg);
  border: 1px solid var(--color-error-border);
  border-radius: var(--radius-md);
  text-align: center;
}

.error-section[hidden] { display: none; }

.error-icon-wrap {
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: var(--color-error-bg);
  border: 1px solid var(--color-error-border);
  color: var(--color-error);
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 0.875rem;
}

.error-message {
  font-size: 0.9375rem;
  color: var(--color-error);
  margin-bottom: 1.25rem;
  line-height: 1.55;
}

/* ── Trust Strip ────────────────────────────────────────────────────── */
.trust-strip {
  display: flex;
  align-items: center;
  justify-content: center;
  flex-wrap: wrap;
  gap: 0.5rem 1.75rem;
  list-style: none;
  margin-top: 1.5rem;
  padding: 0;
}

.trust-item {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  font-size: 0.8125rem;
  color: var(--text-muted);
}

.trust-icon {
  color: var(--green-500);
  line-height: 0;
  opacity: 0.75;
}

/* ── Sections (How it works, FAQ) ───────────────────────────────────── */
.section {
  padding: 5rem 2rem;
  border-top: 1px solid var(--border-subtle);
}

.section-inner {
  max-width: 860px;
  margin: 0 auto;
}

.section-inner--narrow {
  max-width: 640px;
}

.section-title {
  font-size: clamp(1.5rem, 3vw, 2.25rem);
  font-weight: 800;
  letter-spacing: -0.03em;
  margin-bottom: 0.5rem;
  color: var(--text-primary);
}

.section-subtitle {
  font-size: 1rem;
  color: var(--text-secondary);
  margin-bottom: 3rem;
}

/* How it works — numbered steps */
.steps-list {
  list-style: none;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 2rem;
}

.step-item {
  display: flex;
  flex-direction: column;
  gap: 0.875rem;
  padding: 1.75rem;
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  transition: border-color var(--t-base), box-shadow var(--t-base);
}

.step-item:hover {
  border-color: var(--green-border);
  box-shadow: 0 0 24px var(--green-muted);
}

.step-number {
  font-size: 0.75rem;
  font-weight: 800;
  letter-spacing: 0.12em;
  color: var(--green-500);
  font-variant-numeric: tabular-nums;
}

.step-title {
  font-size: 1rem;
  font-weight: 700;
  color: var(--text-primary);
  letter-spacing: -0.01em;
}

.step-desc {
  font-size: 0.9rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

/* FAQ */
.faq-list {
  display: flex;
  flex-direction: column;
  gap: 0;
}

.faq-item {
  padding: 1.375rem 0;
  border-bottom: 1px solid var(--border-subtle);
}

.faq-item:last-child { border-bottom: none; }

.faq-q {
  font-size: 0.9375rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 0.4rem;
}

.faq-a {
  font-size: 0.9rem;
  color: var(--text-secondary);
  line-height: 1.65;
}

/* ── Footer ─────────────────────────────────────────────────────────── */
.site-footer {
  border-top: 1px solid var(--border-subtle);
  padding: 2rem;
  text-align: center;
}

.footer-inner {
  display: flex;
  flex-direction: column;
  gap: 0.375rem;
}

.footer-nav {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.75rem;
  margin-bottom: 0.75rem;
}

.footer-nav-link {
  font-size: 0.8125rem;
  color: var(--text-secondary);
  text-decoration: none;
  transition: color var(--t-fast);
}

.footer-nav-link:hover { color: var(--green-400); }

.footer-nav-sep {
  color: var(--text-muted);
  font-size: 0.75rem;
}

.footer-legal,
.footer-copy {
  font-size: 0.8rem;
  color: var(--text-muted);
}

/* ── Responsive ─────────────────────────────────────────────────────── */
@media (max-width: 640px) {
  .site-header { position: relative; }

  .header-inner { padding: 0 1.25rem; }

  .header-nav { display: none; }

  .hero-section { padding: 3rem 1.25rem 0; }

  .hero-glow { width: 420px; }

  .main-content { padding: 0 0 3rem; }

  .card {
    border-radius: var(--radius-lg);
    padding: 2rem 1.25rem;
    max-width: 100%;
  }

  .form-row {
    flex-direction: column;
    gap: 0;
  }

  .form-group--half { margin-bottom: 1.25rem; }

  .section { padding: 3rem 1.25rem; }

  .steps-list { grid-template-columns: 1fr; }

  .trust-strip { gap: 0.5rem 1rem; }
}

@media (max-width: 400px) {
  .hero-title { font-size: 1.75rem; }

  .btn { font-size: 0.9375rem; padding: 0.8rem 1.25rem; }
}

/* ── Reduced motion ─────────────────────────────────────────────────── */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
  }
  .badge-dot { animation: none; }
  .spinner { animation-duration: 1200ms !important; }
}

/* ── Format hint ─────────────────────────────────────────────────────────── */
.format-hint {
  display: block;
  margin-top: 0.375rem;
  font-size: 0.75rem;
  color: var(--color-text-muted);
  min-height: 1em;
  transition: color var(--transition-fast);
}

.format-hint--lossless {
  color: var(--color-accent);
}

/* ── Progress meta (percentage + ETA) ───────────────────────────────────── */
.progress-meta {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-top: 0.5rem;
  font-size: 0.75rem;
}

.progress-pct {
  color: var(--color-accent);
  font-weight: 700;
  min-width: 2.5rem;
}

.progress-eta {
  color: var(--color-text-muted);
  text-align: right;
}

/* ── Progress steps ──────────────────────────────────────────────────────── */
.progress-steps {
  list-style: none;
  margin-top: 1.25rem;
  display: flex;
  flex-direction: column;
  gap: 0.625rem;
  padding: 0;
}

.progress-step {
  display: flex;
  align-items: center;
  gap: 0.625rem;
  font-size: 0.8125rem;
  color: var(--color-text-muted);
  transition: color var(--transition-base);
}

.progress-step[data-state="active"] {
  color: var(--color-text-primary);
}

.progress-step[data-state="done"] {
  color: var(--color-accent);
}

.step-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background-color: var(--color-border);
  flex-shrink: 0;
  transition: background-color var(--transition-base), transform var(--transition-fast);
}

.progress-step[data-state="active"] .step-dot {
  background-color: var(--color-accent);
  animation: pulse-dot 1.2s ease-in-out infinite;
}

.progress-step[data-state="done"] .step-dot {
  background-color: var(--color-accent);
}

@keyframes pulse-dot {
  0%, 100% { transform: scale(1);   opacity: 1; }
  50%       { transform: scale(1.4); opacity: 0.7; }
}