:root {
  --serif: "Songti SC", "Noto Serif CJK SC", "Source Han Serif SC", "STSong", serif;
  --sans: "PingFang SC", "Hiragino Sans GB", "HarmonyOS Sans SC", "Microsoft YaHei", system-ui, sans-serif;
  --mono: ui-monospace, "SF Mono", "JetBrains Mono", monospace;

  --bg: #12100d;
  --bg-raise: #191713;
  --panel: #171410;
  --line: rgba(240, 233, 219, 0.14);
  --line-strong: rgba(240, 233, 219, 0.3);
  --ink: #efe8da;
  --ink-dim: #b0a795;
  --ink-faint: #918878;
  --accent: #e2522d;
  --accent-ink: #171310;
  --accent-soft: rgba(226, 82, 45, 0.13);
  --shadow: 0 18px 60px rgba(0, 0, 0, 0.35);

  --radius-panel: 4px;
  --radius-control: 3px;

  --maxw: 1240px;
  --pad: 40px;
  color-scheme: dark;
}

@media (prefers-color-scheme: light) {
  :root {
    --bg: #f1ebdf;
    --bg-raise: #f8f3e8;
    --panel: #f8f2e5;
    --line: rgba(27, 24, 20, 0.16);
    --line-strong: rgba(27, 24, 20, 0.34);
    --ink: #1b1814;
    --ink-dim: #595245;
    --ink-faint: #6d6455;
    --accent: #bd3a19;
    --accent-ink: #fdf8ed;
    --accent-soft: rgba(189, 58, 25, 0.1);
    --shadow: 0 18px 50px rgba(59, 47, 32, 0.12);
    color-scheme: light;
  }
}

* { box-sizing: border-box; }

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

body {
  margin: 0;
  min-height: 100dvh;
  background:
    radial-gradient(900px 520px at 12% -8%, var(--accent-soft), transparent 62%),
    var(--bg);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

::selection {
  background: var(--accent);
  color: var(--accent-ink);
}

button, input, textarea {
  font: inherit;
  color: inherit;
}

button { cursor: pointer; }

a { color: inherit; }

.skip-link {
  position: absolute;
  left: 16px;
  top: -80px;
  z-index: 100;
  padding: 10px 16px;
  background: var(--accent);
  color: var(--accent-ink);
  text-decoration: none;
  border-radius: var(--radius-control);
  transition: top 160ms ease;
}
.skip-link:focus { top: 16px; }

.grain {
  position: fixed;
  inset: 0;
  z-index: 90;
  pointer-events: none;
  opacity: 0.05;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='140' height='140'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='2'/%3E%3C/filter%3E%3Crect width='140' height='140' filter='url(%23n)' opacity='0.55'/%3E%3C/svg%3E");
}

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
}

.site-head {
  position: relative;
  z-index: 10;
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 0 var(--pad);
  height: 68px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-bottom: 1px solid var(--line);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  font-family: var(--serif);
  font-size: 18px;
  letter-spacing: 0.06em;
}

.brand-mark {
  width: 24px;
  height: 24px;
  color: var(--accent);
}

.site-nav {
  display: flex;
  align-items: center;
  gap: 28px;
  font-size: 13px;
  letter-spacing: 0.04em;
}

.site-nav a {
  color: var(--ink-dim);
  text-decoration: none;
  padding: 6px 0;
  border-bottom: 1px solid transparent;
  transition: color 160ms ease, border-color 160ms ease;
}

.site-nav a:hover {
  color: var(--ink);
  border-bottom-color: var(--line-strong);
}

main {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 0 var(--pad);
}

.workspace {
  display: grid;
  grid-template-columns: 1.04fr 0.96fr;
  gap: clamp(32px, 5vw, 72px);
  align-items: start;
  padding: clamp(40px, 6vw, 84px) 0 clamp(56px, 8vw, 104px);
}

.kicker {
  margin: 0 0 22px;
  font-size: 12px;
  letter-spacing: 0.22em;
  color: var(--accent);
}

h1 {
  margin: 0;
  font-family: var(--serif);
  font-weight: 600;
  font-size: clamp(2.75rem, 5.6vw, 4.9rem);
  line-height: 1.08;
  letter-spacing: -0.025em;
}

.accent-word {
  position: relative;
  color: var(--accent);
  display: inline-block;
}

.accent-word::after {
  content: "";
  position: absolute;
  left: -0.04em;
  right: -0.04em;
  bottom: 0.03em;
  height: 0.07em;
  background: var(--accent);
  opacity: 0.42;
  transform-origin: left center;
  animation: underline-in 900ms cubic-bezier(0.16, 1, 0.3, 1) 260ms both;
}

@keyframes underline-in {
  from { transform: scaleX(0); }
  to { transform: scaleX(1); }
}

.lede {
  margin: 26px 0 0;
  max-width: 31em;
  font-size: 16.5px;
  line-height: 1.85;
  color: var(--ink-dim);
}

.samples {
  margin-top: 30px;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px 18px;
  font-size: 13px;
}

.samples-label { color: var(--ink-faint); }

.chip {
  padding: 4px 0;
  border: 0;
  border-bottom: 1px solid var(--line-strong);
  background: none;
  color: var(--ink-dim);
  font-size: 13px;
  letter-spacing: 0.02em;
  transition: color 160ms ease, border-color 160ms ease;
}

.chip:hover {
  color: var(--accent);
  border-bottom-color: var(--accent);
}

.promise {
  margin-top: 44px;
  display: flex;
  flex-wrap: wrap;
  gap: 0;
  border-top: 1px solid var(--line);
  padding-top: 22px;
}

.promise-item {
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 0 28px;
  border-left: 1px solid var(--line);
}

.promise-item:first-child {
  padding-left: 0;
  border-left: 0;
}

.promise-num {
  font-family: var(--serif);
  font-size: 26px;
  color: var(--ink);
  line-height: 1;
  white-space: nowrap;
}

.promise-text {
  font-size: 12px;
  color: var(--ink-faint);
  letter-spacing: 0.02em;
  max-width: 9em;
  line-height: 1.5;
}

.composer {
  position: relative;
  border: 1px solid var(--line);
  border-radius: var(--radius-panel);
  background: linear-gradient(180deg, var(--bg-raise), var(--panel));
  padding: 24px;
  box-shadow: var(--shadow);
}

.composer:focus-within {
  border-color: color-mix(in srgb, var(--accent) 45%, var(--line));
}

.composer-head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 16px;
}

.composer-head label {
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--ink-dim);
}

.char-count {
  font-family: var(--mono);
  font-size: 11px;
  color: var(--ink-faint);
  font-variant-numeric: tabular-nums;
}

textarea {
  display: block;
  width: 100%;
  min-height: 216px;
  margin-top: 12px;
  padding: 0;
  border: 0;
  background: transparent;
  color: var(--ink);
  font-size: 15px;
  line-height: 1.9;
  resize: vertical;
}

textarea::placeholder { color: var(--ink-faint); }

textarea:focus { outline: none; }

.composer-tools {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: 14px;
  border-top: 1px solid var(--line);
  font-size: 12.5px;
}

.file-btn {
  color: var(--ink-dim);
  border-bottom: 1px dashed var(--line-strong);
  cursor: pointer;
  transition: color 160ms ease;
}

.file-btn:hover { color: var(--accent); }

.link-btn {
  padding: 0;
  border: 0;
  background: none;
  color: var(--ink-faint);
  font-size: 12.5px;
  transition: color 160ms ease;
}

.link-btn:hover { color: var(--ink); }

.style-picker {
  margin: 20px 0 0;
  padding: 0;
  border: 0;
}

.style-picker legend {
  padding: 0;
  margin-bottom: 8px;
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--ink-dim);
}

.segmented {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  border: 1px solid var(--line);
  border-radius: var(--radius-control);
  overflow: hidden;
}

.segmented button {
  min-height: 42px;
  padding: 0 6px;
  border: 0;
  border-left: 1px solid var(--line);
  background: transparent;
  color: var(--ink-faint);
  font-size: 12.5px;
  letter-spacing: 0.02em;
  transition: color 160ms ease, background 160ms ease;
}

.segmented button:first-child { border-left: 0; }

.segmented button:hover { color: var(--ink); }

.segmented button[aria-checked="true"] {
  background: var(--accent-soft);
  color: var(--accent);
  box-shadow: inset 0 -2px 0 var(--accent);
}

.primary-btn {
  width: 100%;
  min-height: 54px;
  margin-top: 18px;
  padding: 0 20px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  border: 1px solid var(--accent);
  border-radius: var(--radius-control);
  background: var(--accent);
  color: var(--accent-ink);
  font-size: 15px;
  font-weight: 600;
  letter-spacing: 0.06em;
  transition: transform 180ms cubic-bezier(0.16, 1, 0.3, 1), filter 180ms ease, opacity 180ms ease;
}

.primary-btn:hover { filter: brightness(1.06); transform: translateY(-1px); }
.primary-btn:active { transform: translateY(0) scale(0.995); }

.primary-btn[disabled] {
  opacity: 0.62;
  cursor: progress;
  transform: none;
  filter: none;
}

.btn-arrow {
  font-size: 18px;
  line-height: 1;
}

.primary-btn.is-loading .btn-arrow {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--accent-ink);
  font-size: 0;
  animation: pulse 900ms ease-in-out infinite;
}

@keyframes pulse {
  0%, 100% { opacity: 0.3; transform: scale(0.8); }
  50% { opacity: 1; transform: scale(1); }
}

.form-hint {
  margin: 12px 0 0;
  font-size: 12px;
  color: var(--ink-faint);
  line-height: 1.6;
}

.form-error {
  margin: 12px 0 0;
  padding: 10px 12px;
  border-left: 2px solid var(--accent);
  background: var(--accent-soft);
  color: var(--ink);
  font-size: 13px;
  line-height: 1.6;
}

.stage {
  border-top: 1px solid var(--line);
  padding: clamp(56px, 7vw, 92px) 0 clamp(48px, 6vw, 76px);
  scroll-margin-top: 24px;
}

.stage-head {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  gap: 24px;
  margin-bottom: 36px;
}

.stage-label {
  margin: 0 0 10px;
  font-size: 12px;
  letter-spacing: 0.2em;
  color: var(--accent);
}

.stage-head h2 {
  margin: 0;
  font-family: var(--serif);
  font-weight: 600;
  font-size: clamp(2rem, 3.8vw, 3.1rem);
  line-height: 1.2;
  letter-spacing: -0.01em;
}

.song-summary {
  margin: 12px 0 0;
  max-width: 36em;
  font-size: 14px;
  line-height: 1.8;
  color: var(--ink-dim);
}

.song-meta {
  font-family: var(--mono);
  font-size: 11.5px;
  color: var(--ink-faint);
  letter-spacing: 0.04em;
  text-align: right;
  white-space: nowrap;
  padding-bottom: 6px;
}

.sk {
  display: inline-block;
  background: linear-gradient(
    90deg,
    var(--line) 0%,
    color-mix(in srgb, var(--line-strong) 70%, transparent) 45%,
    var(--line) 90%
  );
  background-size: 300% 100%;
  animation: shimmer 1.5s ease-in-out infinite;
}

.sk-line {
  height: 0.78em;
  border-radius: 2px;
  vertical-align: middle;
}

@keyframes shimmer {
  from { background-position: 120% 0; }
  to { background-position: -120% 0; }
}

.stage-grid {
  display: grid;
  grid-template-columns: 1.3fr 0.7fr;
  gap: 0;
  border: 1px solid var(--line);
  border-radius: var(--radius-panel);
  background: var(--panel);
  overflow: hidden;
}

.lyrics-panel {
  padding: 22px 30px 18px;
  min-width: 0;
}

.player {
  display: flex;
  align-items: center;
  gap: 18px;
  padding-bottom: 22px;
  border-bottom: 1px solid var(--line);
}

.play-btn {
  flex: 0 0 auto;
  display: inline-flex;
  align-items: center;
  gap: 9px;
  height: 44px;
  padding: 0 18px;
  border: 1px solid var(--accent);
  border-radius: var(--radius-control);
  background: var(--accent);
  color: var(--accent-ink);
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.08em;
  transition: filter 160ms ease, transform 160ms ease;
}

.play-btn:hover { filter: brightness(1.07); }
.play-btn:active { transform: scale(0.98); }

.play-btn.is-playing {
  background: transparent;
  color: var(--accent);
}

.play-glyph { font-size: 11px; line-height: 1; }

.wave-wrap {
  flex: 1 1 auto;
  min-width: 0;
  height: 44px;
}

#waveCanvas {
  display: block;
  width: 100%;
  height: 44px;
}

.play-state {
  flex: 0 0 auto;
  font-family: var(--mono);
  font-size: 11px;
  color: var(--ink-faint);
  min-width: 44px;
  text-align: right;
}

.lyrics {
  list-style: none;
  margin: 6px 0 0;
  padding: 0;
  counter-reset: none;
}

.lyric-line {
  display: grid;
  grid-template-columns: 34px 1fr;
  gap: 8px;
  align-items: baseline;
  padding: 13px 0;
  color: var(--ink-dim);
  border-bottom: 1px solid transparent;
  transition: color 220ms ease, padding-left 220ms ease, border-color 220ms ease;
}

.lyric-line:last-child { border-bottom: 0; }

.lyric-line .line-no {
  font-family: var(--mono);
  font-size: 10.5px;
  color: var(--ink-faint);
  transition: color 220ms ease;
}

.lyric-line .line-text {
  font-family: var(--serif);
  font-size: clamp(19px, 1.7vw, 22px);
  line-height: 1.62;
  letter-spacing: 0.01em;
}

.lyric-line.stanza-start { margin-top: 14px; }

.lyric-line.is-current {
  color: var(--ink);
  padding-left: 10px;
  border-bottom-color: var(--line);
}

.lyric-line.is-current .line-no { color: var(--accent); }

.lyric-line.is-past { color: var(--ink-faint); }

.points-panel {
  padding: 22px 26px;
  border-left: 1px solid var(--line);
  background: color-mix(in srgb, var(--bg-raise) 70%, transparent);
  display: flex;
  flex-direction: column;
}

.points-panel h3 {
  margin: 0 0 18px;
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.18em;
  color: var(--ink-dim);
}

.points {
  list-style: none;
  margin: 0 0 24px;
  padding: 0;
  display: grid;
  gap: 13px;
  flex: 1 1 auto;
}

.points li {
  display: grid;
  grid-template-columns: 22px 1fr;
  gap: 10px;
  font-size: 13.5px;
  line-height: 1.7;
  color: var(--ink-dim);
}

.point-no {
  font-family: var(--serif);
  font-size: 15px;
  color: var(--accent);
  line-height: 1.5;
}

.actions {
  display: grid;
  gap: 8px;
}

.action-btn {
  min-height: 42px;
  padding: 0 14px;
  border: 1px solid var(--line);
  border-radius: var(--radius-control);
  background: transparent;
  color: var(--ink-dim);
  font-size: 12.5px;
  letter-spacing: 0.06em;
  text-align: left;
  transition: border-color 160ms ease, color 160ms ease, background 160ms ease;
}

.action-btn:hover:not([disabled]) {
  border-color: var(--line-strong);
  color: var(--ink);
}

.action-btn:first-child {
  border-color: color-mix(in srgb, var(--accent) 55%, var(--line));
  color: var(--accent);
}

.action-btn:first-child:hover:not([disabled]) {
  background: var(--accent-soft);
  color: var(--accent);
}

.action-btn[disabled] { opacity: 0.45; cursor: not-allowed; }

.audio-note {
  margin: 14px 0 0;
  font-size: 11.5px;
  line-height: 1.6;
  color: var(--ink-faint);
  min-height: 2.6em;
}

.method {
  border-top: 1px solid var(--line);
  padding: clamp(56px, 7vw, 92px) 0 clamp(40px, 5vw, 64px);
}

.method h2 {
  margin: 0 0 40px;
  font-family: var(--serif);
  font-weight: 600;
  font-size: clamp(1.7rem, 3vw, 2.4rem);
  letter-spacing: -0.01em;
}

.steps {
  list-style: none;
  margin: 0;
  padding: 0;
}

.step {
  display: grid;
  grid-template-columns: 64px minmax(0, 1fr) auto;
  gap: 24px;
  align-items: baseline;
  padding: 26px 0;
  border-top: 1px solid var(--line);
}

.step:last-child { border-bottom: 1px solid var(--line); }

.step-num {
  font-family: var(--serif);
  font-size: 30px;
  color: var(--accent);
  line-height: 1;
}

.step-body h3 {
  margin: 0 0 6px;
  font-family: var(--serif);
  font-size: 19px;
  font-weight: 600;
  letter-spacing: 0.01em;
}

.step-body p {
  margin: 0;
  max-width: 46em;
  font-size: 14px;
  line-height: 1.8;
  color: var(--ink-dim);
}

.step-note {
  font-family: var(--mono);
  font-size: 11px;
  color: var(--ink-faint);
  letter-spacing: 0.02em;
  white-space: nowrap;
}

.manifesto {
  padding: clamp(64px, 9vw, 120px) 0 clamp(64px, 9vw, 120px);
  padding-left: clamp(0px, 8vw, 120px);
  border-top: 1px solid var(--line);
  max-width: 980px;
}

.manifesto-line {
  margin: 0;
  font-family: var(--serif);
  font-weight: 600;
  font-size: clamp(2rem, 4.6vw, 3.6rem);
  line-height: 1.4;
  letter-spacing: -0.01em;
}

.manifesto-sub {
  margin: 28px 0 0;
  max-width: 38em;
  font-size: 14px;
  line-height: 1.9;
  color: var(--ink-dim);
}

.site-foot {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 28px var(--pad) 34px;
  border-top: 1px solid var(--line);
  display: flex;
  flex-wrap: wrap;
  gap: 12px 28px;
  align-items: center;
  justify-content: space-between;
  font-size: 12px;
  color: var(--ink-faint);
}

.site-foot a {
  color: var(--ink-dim);
  text-decoration: none;
  border-bottom: 1px solid var(--line);
  padding-bottom: 2px;
}

.site-foot a:hover { color: var(--accent); border-bottom-color: var(--accent); }

.site-foot .foot-note {
  margin-right: auto;
  margin-left: 18px;
}

@media (max-width: 980px) {
  .workspace {
    grid-template-columns: 1fr;
    gap: 44px;
  }

  .promise { margin-top: 32px; }

  .stage-grid { grid-template-columns: 1fr; }

  .points-panel {
    border-left: 0;
    border-top: 1px solid var(--line);
  }

  .step { grid-template-columns: 48px minmax(0, 1fr); }
  .step-note { grid-column: 2; }
}

@media (max-width: 720px) {
  :root { --pad: 20px; }

  .site-head { height: 60px; }

  .site-nav { gap: 18px; font-size: 12.5px; }

  .site-nav a[href="#stage"] { display: none; }

  h1 { font-size: clamp(2.5rem, 12vw, 3.4rem); }

  .promise {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 18px 0;
  }

  .promise-item:nth-child(3) {
    grid-column: 1 / -1;
    padding-left: 0;
    border-left: 0;
    border-top: 1px solid var(--line);
    padding-top: 16px;
  }

  .promise-item { padding: 0 18px; }
  .promise-item:first-child { padding-left: 0; }

  .segmented { grid-template-columns: 1fr 1fr; }
  .segmented button:nth-child(3) { border-left: 0; border-top: 1px solid var(--line); }
  .segmented button:nth-child(4) { border-top: 1px solid var(--line); }

  .stage-head {
    flex-direction: column;
    align-items: flex-start;
    gap: 12px;
  }

  .song-meta { text-align: left; padding-bottom: 0; }

  .lyrics-panel { padding: 18px 18px 12px; }
  .points-panel { padding: 20px 18px; }

  .player { flex-wrap: wrap; gap: 12px; }
  .wave-wrap { order: 3; flex-basis: 100%; }
  .play-state { margin-left: auto; }

  .line-text { font-size: 19px; }

  .manifesto { padding-left: 0; }

  .site-foot .foot-note {
    margin-left: 0;
    flex-basis: 100%;
  }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }

  *, *::before, *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
  }
}