/* Opus to MP3 — WhatsApp Voice Note Converter. Animated modern UI, no webfonts. */
:root {
  --bg: #f8fafc;
  --surface: #ffffff;
  --ink: #0f172a;
  --muted: #475569;
  --line: #e2e8f0;
  --accent: #0e7490;
  --accent-strong: #155e75;
  --accent-soft: #ecfeff;
  --accent-glow: rgba(14, 116, 144, .18);
  --good: #15803d;
  --good-soft: #f0fdf4;
  --bad: #b91c1c;
  --bad-soft: #fef2f2;
  --warn-soft: #fffbeb;
  --warn-line: #f59e0b;
  --radius: 14px;
  --shadow: 0 1px 3px rgba(15, 23, 42, .08), 0 8px 24px rgba(15, 23, 42, .06);
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--ink);
  line-height: 1.55;
}
.wrap { max-width: 860px; margin: 0 auto; padding: 0 20px; }
a { color: var(--accent); }
code { background: #f1f5f9; padding: .1em .35em; border-radius: 5px; font-size: .92em; }
kbd {
  background: #f1f5f9; border: 1px solid var(--line); border-bottom-width: 2px;
  padding: .05em .4em; border-radius: 5px; font-size: .9em;
}

.skip-link {
  position: absolute; left: -9999px; top: 0; background: var(--ink); color: #fff;
  padding: 10px 16px; border-radius: 0 0 8px 0; z-index: 10;
}
.skip-link:focus { left: 0; color: #fff; }
:focus-visible { outline: 3px solid var(--accent); outline-offset: 2px; border-radius: 4px; }

/* ------------------------------------------------------------- header ----- */
.site-header { background: var(--surface); border-bottom: 1px solid var(--line); }
.site-header .wrap { display: flex; align-items: baseline; gap: 8px; padding-top: 14px; padding-bottom: 14px; }
.brand { font-weight: 800; font-size: 1.25rem; color: var(--ink); text-decoration: none; letter-spacing: -.02em; }
.brand-sub { color: var(--muted); font-size: .9rem; }

/* --------------------------------------------------------------- hero ----- */
.hero { padding: 40px 0 8px; animation: fade-up .5s ease both; }
.hero h1 { font-size: clamp(1.7rem, 4.5vw, 2.5rem); line-height: 1.15; margin: 0 0 12px; letter-spacing: -.02em; }
.lede { font-size: 1.15rem; color: var(--muted); margin: 0 0 8px; max-width: 62ch; }
.lede strong { color: var(--accent-strong); }
.kw-line { color: var(--muted); margin: 0 0 24px; }
.kw-line strong { color: var(--ink); }

/* ------------------------------------------------------------ warning ----- */
.browser-warning {
  background: var(--warn-soft); border: 1px solid var(--warn-line);
  border-radius: var(--radius); padding: 14px 16px; margin: 12px 0 20px;
}

/* --------------------------------------------------------------- tool ----- */
.tool { margin: 8px 0 32px; }
.dropzone {
  border: 2px dashed #94a3b8; border-radius: var(--radius);
  background: var(--surface); padding: 36px 20px; text-align: center;
  cursor: pointer; transition: border-color .2s, box-shadow .2s, transform .2s;
  animation: fade-up .5s .05s ease both;
}
.dropzone:hover { border-color: var(--accent); }
.dropzone.dragging {
  border-color: var(--accent); background: var(--accent-soft);
  box-shadow: 0 0 0 6px var(--accent-glow);
  transform: scale(1.01);
  animation: dz-pulse 1s ease-in-out infinite;
}
.dz-icon { color: var(--accent); margin-bottom: 8px; }
.dz-icon svg { display: block; margin: 0 auto; animation: bob 2.4s ease-in-out infinite; }
.dz-title { font-size: 1.25rem; font-weight: 700; margin: 0 0 4px; }
.dz-sub { color: var(--muted); margin: 0 0 18px; font-size: .95rem; }

/* ------------------------------------------------------------ buttons ----- */
.btn {
  display: inline-block; font: inherit; font-weight: 650; cursor: pointer;
  border: 1px solid transparent; border-radius: 10px; padding: 10px 18px;
  text-decoration: none; transition: transform .15s, box-shadow .15s, background .15s;
}
.btn:active { transform: translateY(1px); }
.btn:disabled { opacity: .55; cursor: not-allowed; }
.btn-primary { background: var(--accent); color: #fff; box-shadow: 0 2px 8px var(--accent-glow); }
.btn-primary:hover:not(:disabled) { background: var(--accent-strong); }
.btn-secondary { background: var(--surface); border-color: var(--accent); color: var(--accent-strong); }
.btn-secondary:hover:not(:disabled) { background: var(--accent-soft); }
.btn-ghost { background: transparent; color: var(--muted); }
.btn-ghost:hover { background: #f1f5f9; color: var(--ink); }
.btn-small { padding: 7px 12px; font-size: .92rem; border-radius: 8px; }

/* ----------------------------------------------------------- controls ----- */
.controls { margin: 20px 0 8px; animation: fade-up .5s .1s ease both; }
.bitrate-group {
  border: 1px solid var(--line); border-radius: var(--radius);
  background: var(--surface); padding: 12px 14px 16px; margin: 0;
  display: grid; grid-template-columns: repeat(3, 1fr); gap: 10px;
}
.bitrate-group legend { font-weight: 700; padding: 0 6px; }
.radio-card { display: block; cursor: pointer; }
.radio-card input { position: absolute; opacity: 0; }
.radio-card span {
  display: block; border: 1.5px solid var(--line); border-radius: 10px;
  padding: 10px 12px; transition: border-color .15s, background .15s, box-shadow .15s;
}
.radio-card strong { display: block; font-size: 1.02rem; }
.radio-card em { display: block; font-style: normal; color: var(--muted); font-size: .85rem; }
.radio-card input:checked + span {
  border-color: var(--accent); background: var(--accent-soft);
  box-shadow: 0 0 0 3px var(--accent-glow);
}
.radio-card input:focus-visible + span { outline: 3px solid var(--accent); outline-offset: 2px; }
.controls-note { color: var(--muted); font-size: .92rem; margin: 10px 2px 0; }

/* ---------------------------------------------------------- file list ----- */
.file-list { display: grid; gap: 12px; margin: 16px 0; }
.file-card {
  background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 14px 16px; box-shadow: var(--shadow);
  animation: card-in .35s ease both;
}
.file-card.status-done { border-color: #bbf7d0; background: linear-gradient(0deg, var(--good-soft), var(--surface) 55%); }
.file-card.status-error { border-color: #fecaca; background: linear-gradient(0deg, var(--bad-soft), var(--surface) 55%); }
.fc-head { display: flex; align-items: baseline; justify-content: space-between; gap: 12px; }
.fc-name { font-weight: 700; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; min-width: 0; }
.fc-duration {
  flex: none; font-variant-numeric: tabular-nums; font-weight: 800; font-size: 1.15rem;
  color: var(--accent-strong); background: var(--accent-soft);
  padding: 2px 10px; border-radius: 999px;
}
.fc-meta { display: flex; flex-wrap: wrap; gap: 6px 16px; color: var(--muted); font-size: .92rem; margin-top: 4px; }
.fc-progress { margin-top: 12px; display: flex; align-items: center; gap: 10px; }
.fc-progress-bar {
  flex: 1; height: 8px; background: #e2e8f0; border-radius: 999px; overflow: hidden;
}
.fc-progress-fill {
  display: block; height: 100%; width: 0%;
  background: linear-gradient(90deg, var(--accent), #22d3ee);
  border-radius: 999px; transition: width .25s ease;
}
.fc-stage { font-size: .9rem; color: var(--muted); white-space: nowrap; }
.fc-error { color: var(--bad); margin: 10px 0 0; font-size: .95rem; }
.fc-actions { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 12px; }

/* ---------------------------------------------------------- batch bar ----- */
.batch-bar {
  position: sticky; bottom: 16px; z-index: 5;
  display: flex; flex-wrap: wrap; align-items: center; gap: 10px;
  background: var(--ink); color: #fff; border-radius: var(--radius);
  padding: 12px 16px; box-shadow: 0 12px 32px rgba(15, 23, 42, .35);
  animation: slide-up .3s ease both;
}
.batch-summary { flex: 1; min-width: 160px; font-weight: 600; }
.batch-bar .btn-ghost { color: #cbd5e1; }
.batch-bar .btn-ghost:hover { background: rgba(255, 255, 255, .1); color: #fff; }

/* ------------------------------------------------------------ sections ---- */
.privacy, .guide, .faq {
  background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 24px 26px; margin: 0 0 24px; box-shadow: var(--shadow);
}
.privacy h2, .guide h2, .faq h2 { margin: 0 0 12px; font-size: 1.35rem; letter-spacing: -.01em; }
.privacy-grid { display: grid; grid-template-columns: 150px 1fr; gap: 20px; align-items: start; }
.privacy-stat { text-align: center; background: var(--accent-soft); border-radius: var(--radius); padding: 16px 8px; }
.privacy-num { display: block; font-size: 2.6rem; font-weight: 800; color: var(--accent-strong); line-height: 1; font-variant-numeric: tabular-nums; }
.privacy-label { display: block; margin-top: 6px; font-size: .85rem; color: var(--muted); line-height: 1.35; }
.privacy-text p { margin: 0 0 10px; }
.privacy-text details { border-top: 1px solid var(--line); padding-top: 10px; }
.privacy-text summary { cursor: pointer; font-weight: 650; color: var(--accent-strong); }
.privacy-text ol { margin: 10px 0 0; padding-left: 22px; }
.guide .steps { padding-left: 22px; }
.guide .steps li { margin-bottom: 10px; }
.guide h3 { margin: 20px 0 8px; }
.guide ul { padding-left: 22px; }
.guide li { margin-bottom: 6px; }
.faq details { border-top: 1px solid var(--line); padding: 12px 0; }
.faq details:first-of-type { border-top: 0; }
.faq summary { cursor: pointer; font-weight: 650; }
.faq summary:hover { color: var(--accent-strong); }
.faq p { margin: 8px 0 0; color: var(--muted); }

/* ------------------------------------------------------------- footer ----- */
.site-footer { border-top: 1px solid var(--line); padding: 20px 0 32px; color: var(--muted); font-size: .9rem; }

/* ---------------------------------------------------------- animation ----- */
@keyframes fade-up { from { opacity: 0; transform: translateY(10px); } to { opacity: 1; transform: none; } }
@keyframes card-in { from { opacity: 0; transform: translateY(8px) scale(.995); } to { opacity: 1; transform: none; } }
@keyframes slide-up { from { opacity: 0; transform: translateY(14px); } to { opacity: 1; transform: none; } }
@keyframes dz-pulse { 0%, 100% { box-shadow: 0 0 0 6px var(--accent-glow); } 50% { box-shadow: 0 0 0 12px rgba(14, 116, 144, .07); } }
@keyframes bob { 0%, 100% { transform: translateY(0); } 50% { transform: translateY(-4px); } }

/* ---------------------------------------------------------- responsive ---- */
@media (max-width: 640px) {
  .bitrate-group { grid-template-columns: 1fr; }
  .privacy-grid { grid-template-columns: 1fr; }
  .privacy-stat { display: flex; align-items: baseline; gap: 10px; justify-content: center; padding: 12px; }
  .privacy-num { font-size: 2rem; }
  .privacy, .guide, .faq { padding: 18px; }
  .fc-head { flex-wrap: wrap; }
  .fc-duration { order: -1; }
  .batch-bar { bottom: 8px; }
}

/* ------------------------------------------------------ reduced motion ---- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation: none !important; transition: none !important; }
  .dropzone.dragging { animation: none; }
}