:root {
  --bg: #f7f8fa;
  --surface: #ffffff;
  --ink: #14181f;
  --ink-2: #4a5464;
  --ink-3: #7a8595;
  --line: #e3e7ee;
  --line-2: #eef1f6;
  --accent: #2f5fe0;
  --accent-ink: #ffffff;
  --accent-soft: #e8eeff;
  --warn: #b4441f;
  --radius: 12px;
  --shadow: 0 1px 2px rgba(20, 24, 31, .04), 0 8px 24px rgba(20, 24, 31, .05);
}

* { box-sizing: border-box; }

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

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font: 16px/1.6 -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  -webkit-font-smoothing: antialiased;
}

.wrap { width: 100%; max-width: 780px; margin: 0 auto; padding: 0 20px; }

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

code {
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: .92em;
  background: var(--line-2);
  padding: 1px 5px;
  border-radius: 5px;
}

/* ---------- header ---------- */

.site-head {
  border-bottom: 1px solid var(--line);
  background: var(--surface);
}

.head-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  height: 56px;
}

.brand {
  font-weight: 700;
  font-size: 17px;
  letter-spacing: -.01em;
}

.brand-dim { color: var(--accent); margin: 0 1px; }

.head-note {
  font-size: 12.5px;
  color: var(--ink-3);
}

/* ---------- heading ---------- */

h1 {
  font-size: 30px;
  line-height: 1.2;
  letter-spacing: -.02em;
  margin: 34px 0 8px;
}

.lede {
  margin: 0 0 22px;
  color: var(--ink-2);
  font-size: 16.5px;
}

@media (max-width: 600px) {
  h1 { font-size: 25px; margin-top: 26px; }
  .lede { font-size: 15.5px; margin-bottom: 18px; }
  .head-note { display: none; }
}

/* ---------- tool ---------- */

.tool {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 18px;
}

.dropzone {
  border: 1.5px dashed var(--line);
  border-radius: 10px;
  background: #fbfcfe;
  padding: 38px 18px;
  text-align: center;
  cursor: pointer;
  transition: border-color .15s, background .15s;
}

.dropzone:hover,
.dropzone:focus-visible {
  border-color: var(--accent);
  background: var(--accent-soft);
  outline: none;
}

.dropzone.is-over {
  border-color: var(--accent);
  background: var(--accent-soft);
}

.dropzone.is-busy { pointer-events: none; opacity: .55; }

.dz-icon {
  width: 30px;
  height: 30px;
  fill: none;
  stroke: var(--accent);
  stroke-width: 1.7;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.dz-title { margin: 8px 0 4px; font-weight: 600; font-size: 16px; }
.dz-sub { margin: 0; font-size: 13.5px; color: var(--ink-3); }

.dz-note {
  margin: 9px 0 0;
  font-size: 12.5px;
  color: var(--ink-3);
}

.dz-note.is-ready { color: #2c7a4b; }
.dz-note.is-error { color: var(--warn); }

/* ---------- status ---------- */

.status { margin-top: 16px; }

.status-row {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 10px;
  font-size: 14px;
  margin-bottom: 7px;
}

.status-text { color: var(--ink-2); }
.status-pct { color: var(--ink-3); font-variant-numeric: tabular-nums; font-size: 13px; }

.bar {
  height: 6px;
  background: var(--line-2);
  border-radius: 999px;
  overflow: hidden;
}

.bar-fill {
  height: 100%;
  width: 0%;
  background: var(--accent);
  border-radius: 999px;
  transition: width .2s linear;
}

/* ---------- result ---------- */

.result { margin-top: 18px; }

.result-head {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  align-items: flex-start;
  justify-content: space-between;
  padding-bottom: 14px;
  border-bottom: 1px solid var(--line-2);
}

.result-file {
  margin: 0;
  font-weight: 600;
  font-size: 15px;
  word-break: break-all;
}

.result-sub { margin: 2px 0 0; font-size: 13px; color: var(--ink-3); }

.result-actions { display: flex; gap: 8px; flex-wrap: wrap; }

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 0 18px;
  border-radius: 9px;
  font-size: 15px;
  font-weight: 600;
  text-decoration: none;
  cursor: pointer;
  border: 1px solid transparent;
  white-space: nowrap;
}

.btn-primary { background: var(--accent); color: var(--accent-ink); }
.btn-primary:hover { background: #2550c4; }

.btn-ghost { background: var(--surface); color: var(--ink-2); border-color: var(--line); }
.btn-ghost:hover { background: var(--line-2); }

.stats {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 10px;
  margin: 16px 0 0;
}

.stat {
  background: #fbfcfe;
  border: 1px solid var(--line-2);
  border-radius: 9px;
  padding: 10px 12px;
  min-width: 0;
}

.stat-k {
  font-size: 11.5px;
  text-transform: uppercase;
  letter-spacing: .04em;
  color: var(--ink-3);
  margin: 0 0 3px;
}

.stat-v {
  margin: 0;
  font-size: 17px;
  font-weight: 650;
  font-variant-numeric: tabular-nums;
  overflow-wrap: anywhere;
}

.stat-note {
  margin: 2px 0 0;
  font-size: 11.5px;
  color: var(--ink-3);
}

@media (max-width: 600px) {
  .stats { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .result-actions { width: 100%; }
  .btn { flex: 1 1 auto; }
}

/* ---------- piano roll ---------- */

.roll-wrap { margin-top: 18px; }

.roll-title {
  margin: 0 0 8px;
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: .04em;
  color: var(--ink-3);
}

.roll-canvas { position: relative; }

.playhead {
  position: absolute;
  top: 0;
  bottom: 0;
  width: 2px;
  margin-left: -1px;
  background: #e0483c;
  border-radius: 1px;
  pointer-events: none;
}

#roll {
  display: block;
  width: 100%;
  height: 240px;
  background: #fbfcfe;
  border: 1px solid var(--line-2);
  border-radius: 9px;
}

.roll-axis {
  display: flex;
  justify-content: space-between;
  margin: 6px 0 0;
  font-size: 12px;
  color: var(--ink-3);
  font-variant-numeric: tabular-nums;
}

/* ---------- error ---------- */

.error {
  margin: 16px 0 0;
  padding: 12px 14px;
  border-radius: 9px;
  background: #fdf1ec;
  border: 1px solid #f3d9cf;
  color: var(--warn);
  font-size: 14px;
  overflow-wrap: anywhere;
}

/* ---------- prose ---------- */

.prose { margin-top: 38px; }

.prose h2 {
  font-size: 20px;
  letter-spacing: -.01em;
  margin: 0 0 12px;
}

.prose h3 { font-size: 15px; margin: 0 0 8px; }

.prose p { color: var(--ink-2); }

.note { font-size: 14px; color: var(--ink-3); }

.fmt-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
  margin: 12px 0;
}

@media (max-width: 600px) {
  .fmt-grid { grid-template-columns: 1fr; }
}

.fmt-card {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 14px 16px;
}

.fmt-card ul {
  margin: 0;
  padding-left: 18px;
  font-size: 14px;
  color: var(--ink-2);
}

.fmt-card li { margin: 2px 0; }

.dim { color: var(--ink-3); font-size: 13px; }

.steps {
  padding-left: 20px;
  color: var(--ink-2);
}

.steps li { margin: 8px 0; }

details {
  border-top: 1px solid var(--line);
  padding: 12px 0;
}

details:last-of-type { border-bottom: 1px solid var(--line); }

summary {
  cursor: pointer;
  font-weight: 600;
  font-size: 15.5px;
  list-style: none;
  display: flex;
  justify-content: space-between;
  gap: 12px;
  align-items: baseline;
}

summary::-webkit-details-marker { display: none; }

summary::after {
  content: "+";
  color: var(--ink-3);
  font-weight: 400;
  font-size: 19px;
  line-height: 1;
}

details[open] summary::after { content: "–"; }

details p {
  margin: 10px 0 2px;
  font-size: 14.5px;
}

/* ---------- footer ---------- */

.site-foot {
  margin-top: 46px;
  border-top: 1px solid var(--line);
  background: var(--surface);
  padding: 18px 0 30px;
}

.site-foot p {
  margin: 0;
  font-size: 13px;
  color: var(--ink-3);
}

.foot-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 18px;
  margin-top: 12px;
}

.foot-nav a {
  display: inline-block;
  min-height: 32px;
  padding: 6px 0;
  font-size: 14px;
  color: var(--ink-2);
  text-decoration: none;
}

.foot-nav a:hover { color: var(--accent); text-decoration: underline; }

/* ---------- text pages (about / privacy / contact) ---------- */

.page-head { margin: 28px 0 6px; }

.page-head h1 { font-size: 28px; line-height: 1.25; margin: 0 0 8px; }

.page-body h2 { font-size: 19px; margin: 26px 0 8px; }

.page-body p, .page-body li { font-size: 15.5px; color: var(--ink-2); }

.page-body ul { padding-left: 20px; }

.page-updated { font-size: 13px; color: var(--ink-3); }

@media (max-width: 600px) {
  .page-head h1 { font-size: 24px; }
  .foot-nav { gap: 4px 16px; }
  .foot-nav a { min-height: 40px; padding: 10px 0; font-size: 15px; }
}