:root {
  --bg: #0a0a0d;
  --grid-line: rgba(255, 255, 255, 0.035);
  --surface: #131317;
  --surface-2: #1a1a20;
  --border: rgba(255, 255, 255, 0.08);
  --text: #e8e8ec;
  --text-dim: #8b8b96;
  --accent: #5d8aef;
  --accent-dim: rgba(93, 138, 239, 0.14);
  --error: #ff6b6b;
  --radius: 10px;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background-color: var(--bg);
  background-image:
    linear-gradient(var(--grid-line) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid-line) 1px, transparent 1px);
  background-size: 32px 32px;
  color: var(--text);
  font-family: -apple-system, "Segoe UI", Roboto, Inter, system-ui, sans-serif;
  min-height: 100vh;
}

body {
  opacity: 0;
  transition: opacity .4s ease;
}
body.loaded { opacity: 1; }

.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 22px 36px;
}

.brand {
  font-size: 20px;
  font-weight: 600;
  letter-spacing: -0.02em;
}

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

.gh-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 38px;
  height: 38px;
  border-radius: 50%;
  background: var(--surface);
  border: 1px solid var(--border);
  color: var(--text-dim);
  text-decoration: none;
  transition: color .15s, border-color .15s;
}
.gh-btn:hover { color: var(--text); border-color: var(--accent); }

.tabs {
  display: flex;
  gap: 22px;
  padding: 0 36px;
  margin-bottom: 28px;
  border-bottom: 1px solid var(--border);
}

.tab-btn {
  background: transparent;
  border: none;
  border-bottom: 2px solid transparent;
  color: var(--text-dim);
  font-size: 14px;
  font-weight: 500;
  padding: 10px 2px 12px;
  margin-bottom: -1px;
  cursor: pointer;
  transition: color .15s, border-color .15s;
}
.tab-btn:hover { color: var(--text); }
.tab-btn.active { color: var(--text); border-color: var(--accent); }

main {
  max-width: 880px;
  margin: 0 auto;
  padding: 0 24px 80px;
}

.tab-panel { display: none; flex-direction: column; gap: 20px; }
.tab-panel.active { display: flex; }
.tab-panel.fade-out { opacity: 0; transform: translateY(5px); transition: opacity .18s ease, transform .18s ease; }
.tab-panel.fade-in { animation: fadeInUp .38s cubic-bezier(.16,.8,.24,1); }

@keyframes fadeInUp {
  from { opacity: 0; transform: translateY(10px); }
  to   { opacity: 1; transform: translateY(0); }
}

.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  transition: border-color .25s ease, transform .25s ease, box-shadow .25s ease;
}
.card:hover { border-color: rgba(255, 255, 255, 0.14); }

.card-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 12px;
}
.card-header h3 { margin: 0; font-size: 15px; font-weight: 600; color: var(--text-dim); }

.mode-switch {
  display: inline-flex;
  background: var(--surface-2);
  border-radius: 999px;
  padding: 3px;
  margin-bottom: 18px;
  gap: 2px;
}

.mode-btn {
  background: transparent;
  border: none;
  color: var(--text-dim);
  font-size: 13px;
  font-weight: 500;
  padding: 7px 16px;
  border-radius: 999px;
  cursor: pointer;
  transition: background .2s cubic-bezier(.2,.7,.3,1), color .2s ease, transform .1s ease;
}
.mode-btn:active { transform: scale(.94); }
.mode-btn.active { background: var(--accent); color: var(--bg); }

.mode-panel { display: none; }
.mode-panel.active { display: block; }

.big-input, input[type=text], input:not([type]) {
  width: 100%;
  background: var(--surface-2);
  border: 1px solid var(--border);
  color: var(--text);
  font-size: 15px;
  padding: 14px 18px;
  border-radius: 999px;
  outline: none;
  margin-bottom: 12px;
  transition: border-color .2s ease, box-shadow .2s ease;
}
.big-input:focus, input:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-dim);
}

.row { display: flex; gap: 10px; align-items: center; flex-wrap: wrap; }
.row input { margin-bottom: 0; flex: 1; min-width: 120px; }

select {
  background: var(--surface-2);
  border: 1px solid var(--border);
  color: var(--text);
  font-size: 14px;
  padding: 12px 14px;
  border-radius: 10px;
  outline: none;
  transition: border-color .2s ease, box-shadow .2s ease;
}
select:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-dim);
}

.primary-btn {
  background: var(--accent);
  color: #05070f;
  border: none;
  font-size: 14px;
  font-weight: 600;
  padding: 12px 22px;
  border-radius: 10px;
  cursor: pointer;
  white-space: nowrap;
  transition: opacity .15s, transform .1s ease;
}
.primary-btn:hover { opacity: .88; }
.primary-btn:active { transform: scale(.96); }
.primary-btn:disabled { opacity: .4; cursor: not-allowed; }

.ghost-btn {
  background: transparent;
  border: 1px solid var(--border);
  color: var(--text-dim);
  font-size: 13px;
  padding: 10px 16px;
  border-radius: 10px;
  cursor: pointer;
  transition: color .15s ease, border-color .15s ease, transform .1s ease;
}
.ghost-btn:hover { color: var(--text); border-color: var(--accent); }
.ghost-btn:active { transform: scale(.96); }

.file-btn { display: inline-flex; cursor: pointer; }

.progress-box { margin-top: 18px; }
.progress-box.hidden { display: none; }
.progress-track {
  height: 6px;
  background: var(--surface-2);
  border-radius: 999px;
  overflow: hidden;
}
.progress-fill {
  height: 100%;
  width: 0%;
  background: var(--accent);
  transition: width .3s cubic-bezier(.2,.7,.3,1);
  box-shadow: 0 0 10px 0 var(--accent-dim);
}
.progress-text { font-size: 13px; color: var(--text-dim); margin-top: 8px; transition: opacity .15s ease; }

.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 12px;
  margin-top: 8px;
}

.result-card {
  animation: fadeInUp .3s cubic-bezier(.2,.7,.3,1) backwards;
  transition: border-color .15s ease, transform .15s ease;
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 10px;
  display: flex;
  gap: 12px;
  align-items: center;
}
.result-card img {
  width: 52px;
  height: 52px;
  border-radius: 8px;
  object-fit: cover;
  background: #222;
  flex-shrink: 0;
}
.result-card .meta { flex: 1; min-width: 0; }
.result-card .title { font-size: 13px; font-weight: 600; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.result-card .artist { font-size: 12px; color: var(--text-dim); white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.result-card:hover { border-color: var(--accent); }
.result-card .dl-btn {
  background: var(--accent-dim);
  color: var(--accent);
  border: none;
  border-radius: 8px;
  padding: 8px 10px;
  transition: transform .1s ease, background .15s ease;
  cursor: pointer;
  font-size: 12px;
  font-weight: 600;
}
.result-card .dl-btn:active { transform: scale(.92); }

.drop-zone {
  border: 2px dashed var(--border);
  border-radius: var(--radius);
  padding: 48px 20px;
  text-align: center;
  transition: border-color .2s ease, background .2s ease, transform .15s ease;
}
.drop-zone.dragover { border-color: var(--accent); background: var(--accent-dim); transform: scale(1.01); }
.drop-zone p { color: var(--text-dim); margin: 8px 0; }
.drop-zone .hint { font-size: 12px; }

.conv-result { margin-top: 20px; }
.conv-result.hidden { display: none; }
#conv-file-info { font-size: 13px; color: var(--text-dim); margin-bottom: 12px; }
#conv-output { margin-top: 14px; font-size: 14px; }
#conv-output a { color: var(--accent); }

.meta-form { margin-top: 18px; display: flex; flex-direction: column; gap: 10px; }
.meta-form.hidden { display: none; }
.meta-cover-row { display: flex; align-items: center; gap: 14px; margin-bottom: 8px; }
.cover-preview {
  width: 72px; height: 72px;
  border-radius: 10px;
  object-fit: cover;
  background: var(--surface-2);
  border: 1px solid var(--border);
}

.batch-list { margin-top: 14px; display: flex; flex-direction: column; gap: 6px; }
.batch-item { font-size: 13px; color: var(--text-dim); display: flex; justify-content: space-between; }
.batch-item .ok { color: #6ee7a8; }
.batch-item .err { color: var(--error); }

.script-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
  margin-bottom: 14px;
}
.script-grid textarea {
  width: 100%;
  height: 340px;
  background: var(--surface-2);
  border: 1px solid var(--border);
  color: var(--text);
  font-family: "Cascadia Code", Consolas, monospace;
  font-size: 13px;
  padding: 14px;
  border-radius: 10px;
  resize: vertical;
  outline: none;
}
.script-grid textarea:focus { border-color: var(--accent); }
.script-error {
  margin-top: 10px;
  color: var(--error);
  font-size: 13px;
  font-family: Consolas, monospace;
}
.script-error.hidden { display: none; }

.hidden { display: none !important; }

.footer {
  position: fixed;
  bottom: 14px;
  left: 0;
  right: 0;
  text-align: center;
  font-size: 11px;
  color: rgba(255, 255, 255, 0.18);
  pointer-events: none;
  letter-spacing: .02em;
}

@media (max-width: 640px) {
  .script-grid { grid-template-columns: 1fr; }
  .topbar { padding: 18px 20px; }
  .tabs { padding: 0 12px; overflow-x: auto; }
}