:root {
  --bg: #f4f9fd;
  --surface: #ffffff;
  --surface-soft: #f2f8ff;
  --ink: #10243a;
  --muted: #64788d;
  --line: #d8e6f2;
  --line-strong: #b9d4e9;
  --blue: #279efe;
  --blue-dark: #0876ce;
  --blue-deep: #075b9d;
  --blue-soft: #e8f4ff;
  --stage: #071c30;
  --danger: #a44716;
  --shadow: 0 18px 48px rgba(16, 76, 122, 0.1);
  font-family: "Microsoft YaHei", "PingFang SC", system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

* { box-sizing: border-box; }

html { color-scheme: light; }

body {
  margin: 0;
  min-width: 320px;
  min-height: 100vh;
  color: var(--ink);
  background: var(--bg);
}

body::before {
  content: "";
  position: fixed;
  inset: 0 0 auto;
  height: 4px;
  background: var(--blue);
  z-index: 30;
}

button,
input,
textarea { font: inherit; }

button { cursor: pointer; }

button:disabled,
input:disabled {
  cursor: not-allowed;
  opacity: 0.58;
}

button:focus-visible,
input:focus-visible,
textarea:focus-visible,
a:focus-visible {
  outline: 3px solid rgba(39, 158, 254, 0.28);
  outline-offset: 3px;
}

.page {
  width: min(1440px, calc(100% - 48px));
  margin: 0 auto;
  padding: 28px 0 40px;
  display: grid;
  gap: 20px;
}

.brand-header {
  min-height: 76px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 28px;
}

.brand-lockup {
  display: flex;
  align-items: center;
  gap: 14px;
}

.brand-mark {
  width: 56px;
  height: 56px;
  flex: 0 0 auto;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 4px;
  border: 1px solid #168ce7;
  border-radius: 14px;
  background: var(--blue);
  box-shadow: 0 10px 24px rgba(39, 158, 254, 0.22);
}

.brand-mark span {
  width: 4px;
  border-radius: 2px;
  background: #fff;
}

.brand-mark span:nth-child(1) { height: 14px; }
.brand-mark span:nth-child(2) { height: 28px; }
.brand-mark span:nth-child(3) { height: 38px; }
.brand-mark span:nth-child(4) { height: 22px; }

.brand-name {
  margin: 0;
  font-size: clamp(24px, 2.6vw, 34px);
  line-height: 1;
  letter-spacing: -0.035em;
  font-weight: 800;
}

.brand-tagline {
  margin: 7px 0 0;
  color: var(--muted);
  font-size: 14px;
  line-height: 1.4;
}

.brand-meta {
  padding-left: 18px;
  border-left: 2px solid var(--blue);
  color: var(--muted);
  font-size: 13px;
  line-height: 1.6;
  text-align: right;
}

.brand-actions {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: 18px;
}

.extension-download {
  min-height: 44px;
  padding: 0 14px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  border: 1px solid var(--blue-dark);
  border-radius: 9px;
  color: #fff;
  background: var(--blue-dark);
  box-shadow: 0 8px 20px rgba(8, 118, 206, 0.18);
  font-size: 13px;
  font-weight: 800;
  text-decoration: none;
  white-space: nowrap;
  transition: transform 160ms ease, box-shadow 160ms ease, background 160ms ease;
}

.extension-download svg {
  width: 17px;
  height: 17px;
  flex: 0 0 auto;
}

.extension-download small {
  padding-left: 8px;
  border-left: 1px solid rgba(255, 255, 255, 0.38);
  color: #d9efff;
  font-size: 11px;
  font-weight: 700;
}

.extension-download:hover {
  background: var(--blue-deep);
  transform: translateY(-1px);
  box-shadow: 0 11px 24px rgba(8, 91, 157, 0.24);
}

.input-panel,
.practice-card,
.loading-card,
.empty-card {
  border: 1px solid var(--line);
  border-radius: 16px;
  background: var(--surface);
  box-shadow: var(--shadow);
}

.input-panel { padding: 22px 24px 24px; }

.input-heading {
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 20px;
  margin-bottom: 14px;
}

.input-heading h2 {
  margin: 0 0 4px;
  font-size: 18px;
  line-height: 1.35;
}

.input-heading p {
  margin: 0;
  color: var(--muted);
  font-size: 13px;
  line-height: 1.5;
}

.input-step {
  color: var(--blue-dark);
  font-size: 12px;
  font-weight: 800;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.url-row {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 12px;
}

.url-label {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.url-input {
  width: 100%;
  min-width: 0;
  height: 52px;
  padding: 0 16px;
  border: 1px solid var(--line-strong);
  border-radius: 10px;
  background: #fbfdff;
  color: var(--ink);
  transition: border-color 160ms ease, box-shadow 160ms ease, background 160ms ease;
}

.url-input::placeholder { color: #8ca0b4; }

.url-input:hover { border-color: #83bdeb; }

.url-input:focus {
  border-color: var(--blue);
  background: #fff;
  box-shadow: 0 0 0 4px rgba(39, 158, 254, 0.1);
}

.primary-btn,
.ghost-btn,
.mini-btn,
.mode-btn {
  border: 1px solid transparent;
  border-radius: 9px;
  font-weight: 800;
  white-space: nowrap;
  transition: transform 160ms ease, box-shadow 160ms ease, border-color 160ms ease, background 160ms ease, color 160ms ease;
}

.primary-btn {
  min-height: 52px;
  padding: 0 26px;
  color: #fff;
  background: var(--blue-dark);
  box-shadow: 0 9px 22px rgba(8, 118, 206, 0.2);
}

.primary-btn:hover:not(:disabled) {
  background: var(--blue-deep);
  transform: translateY(-1px);
  box-shadow: 0 12px 25px rgba(8, 91, 157, 0.24);
}

.ghost-btn {
  min-height: 42px;
  padding: 0 16px;
  border-color: var(--line);
  color: var(--muted);
  background: #fff;
}

.ghost-btn.compact {
  min-height: 30px;
  padding: 0 9px;
  font-size: 12px;
}

.empty-card,
.loading-card {
  min-height: 390px;
  padding: 48px 24px;
  display: grid;
  place-items: center;
  align-content: center;
  gap: 12px;
  text-align: center;
}

.empty-card h2,
.loading-card h2 {
  margin: 6px 0 0;
  font-size: 24px;
}

.empty-card p,
.loading-card p {
  max-width: 470px;
  margin: 0;
  color: var(--muted);
  line-height: 1.65;
}

.empty-icon {
  width: 68px;
  height: 68px;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 4px;
  border: 1px solid #b9dcf8;
  border-radius: 16px;
  background: var(--blue-soft);
}

.empty-icon span {
  width: 4px;
  border-radius: 2px;
  background: var(--blue-dark);
}

.empty-icon span:nth-child(1) { height: 16px; }
.empty-icon span:nth-child(2) { height: 30px; }
.empty-icon span:nth-child(3) { height: 42px; }
.empty-icon span:nth-child(4) { height: 24px; }
.empty-hint { font-size: 13px; }

.loader {
  width: 46px;
  height: 46px;
  border-radius: 50%;
  border: 4px solid var(--blue-soft);
  border-top-color: var(--blue-dark);
  animation: spin 820ms linear infinite;
}

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

.practice-card {
  padding: 22px;
  display: grid;
  gap: 18px;
}

.song-head {
  display: flex;
  align-items: start;
  justify-content: space-between;
  gap: 18px;
  padding: 0 2px 2px;
}

.song-kicker {
  display: block;
  margin-bottom: 7px;
  color: var(--blue-dark);
  font-size: 12px;
  font-weight: 800;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.song-head h2 {
  margin: 0;
  font-size: clamp(25px, 3vw, 40px);
  line-height: 1.1;
  letter-spacing: -0.025em;
}

.song-head p {
  max-width: 760px;
  margin: 8px 0 0;
  color: var(--muted);
  overflow-wrap: anywhere;
}

.recognition-note {
  margin-top: 10px !important;
  padding: 9px 11px;
  border-left: 3px solid var(--blue);
  background: var(--blue-soft);
  color: var(--blue-deep) !important;
  font-size: 13px;
  line-height: 1.45;
}

.practice-workspace {
  display: grid;
  grid-template-columns: minmax(0, 1.55fr) minmax(370px, 0.85fr);
  gap: 18px;
  align-items: stretch;
}

.video-pane,
.lyrics-pane { min-width: 0; }

.player-box {
  min-height: 330px;
  aspect-ratio: 16 / 9;
  padding: 10px;
  display: grid;
  align-items: center;
  position: relative;
  overflow: hidden;
  border: 1px solid #163a59;
  border-radius: 12px;
  background: var(--stage);
  color: #fff;
  box-shadow: inset 0 0 0 1px rgba(255, 255, 255, 0.04);
  transition: box-shadow 180ms ease, transform 180ms ease;
}

.native-player {
  width: 100%;
  height: 100%;
  border: 0;
  border-radius: 8px;
  background: #000;
  object-fit: contain;
}

.sync-pill {
  position: absolute;
  right: 18px;
  bottom: 18px;
  padding: 7px 10px;
  border: 1px solid rgba(255, 255, 255, 0.45);
  border-radius: 7px;
  color: #073658;
  background: rgba(241, 248, 255, 0.94);
  font-size: 12px;
  font-weight: 800;
  pointer-events: none;
}

.player-error {
  position: absolute;
  inset: 18px 18px auto;
  padding: 10px 12px;
  border: 1px solid rgba(255, 193, 136, 0.55);
  border-radius: 8px;
  color: #fff7ed;
  background: rgba(91, 42, 13, 0.9);
  font-size: 13px;
  line-height: 1.45;
}

.video-fallback {
  max-width: 440px;
  margin: auto;
  padding: 30px;
  display: grid;
  gap: 10px;
  border: 1px solid #244d6c;
  border-radius: 10px;
  background: #0c2942;
  text-align: center;
}

.video-fallback strong { font-size: 18px; }
.video-fallback span { color: #b9cede; line-height: 1.6; }

.lyrics-pane {
  height: 100%;
  display: grid;
  grid-template-rows: auto auto minmax(0, 1fr);
  gap: 10px;
}

.lyrics-toolbar,
.line-editor {
  border: 1px solid var(--line);
  border-radius: 10px;
  background: #fff;
}

.lyrics-toolbar {
  padding: 11px 12px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
}

.lyrics-toolbar strong {
  display: block;
  margin-top: 2px;
  color: var(--ink);
  font-size: 14px;
}

.panel-label,
.lyrics-count {
  color: var(--muted);
  font-size: 12px;
  font-weight: 800;
}

.lyrics-actions {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: 6px;
  flex-wrap: wrap;
}

.line-editor {
  padding: 12px;
  display: grid;
  gap: 9px;
  border-color: #b8daf5;
  background: var(--blue-soft);
}

.line-editor > div:first-child {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
}

.line-editor span {
  color: var(--muted);
  font-size: 12px;
  font-weight: 800;
}

.line-editor strong,
.lyric-item span {
  font-family: ui-monospace, "SFMono-Regular", Consolas, "Liberation Mono", monospace;
  font-variant-numeric: tabular-nums;
}

.line-editor strong { color: var(--blue-deep); }

.line-editor p {
  margin: 0;
  color: var(--ink);
  font-size: 15px;
  font-weight: 800;
  line-height: 1.4;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.playback-mode-actions {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 8px;
}

.mode-btn {
  min-height: 36px;
  padding: 0 10px;
  border-color: var(--line-strong);
  color: var(--blue-deep);
  background: #fff;
  font-size: 13px;
}

.mode-btn:hover { border-color: var(--blue); background: #f8fcff; }

.mode-btn[aria-pressed="true"] {
  border-color: var(--blue-dark);
  color: #fff;
  background: var(--blue-dark);
  box-shadow: 0 6px 16px rgba(8, 118, 206, 0.2);
}

.lyrics-list {
  min-height: 0;
  padding: 1px 5px 1px 0;
  display: grid;
  align-content: start;
  gap: 8px;
  overflow-y: auto;
  scroll-behavior: smooth;
}

.lyrics-list::-webkit-scrollbar { width: 8px; }
.lyrics-list::-webkit-scrollbar-thumb { border-radius: 4px; background: #bfd5e7; }

.lyric-item {
  width: 100%;
  min-height: 56px;
  padding: 10px 12px;
  display: grid;
  grid-template-columns: 58px 1fr;
  gap: 11px;
  align-items: center;
  border: 1px solid var(--line);
  border-radius: 9px;
  background: #fff;
  color: var(--ink);
  text-align: left;
  transition: box-shadow 160ms ease, transform 160ms ease, border-color 160ms ease, background 160ms ease;
}

.lyric-item.active {
  border-color: #78bff3;
  border-left: 4px solid var(--blue-dark);
  padding-left: 9px;
  background: var(--blue-soft);
  box-shadow: 0 8px 18px rgba(39, 158, 254, 0.1);
}

.lyric-item span { color: var(--muted); font-size: 13px; }
.lyric-item.active span { color: var(--blue-deep); font-weight: 800; }

.lyric-item b {
  font-size: 16px;
  line-height: 1.4;
}

.lyric-item:hover {
  border-color: #75bced;
  transform: translateY(-1px);
  box-shadow: 0 9px 20px rgba(26, 103, 161, 0.11);
}

.playing-flash { animation: playFlash 520ms ease; }
.player-box.playing-flash { box-shadow: 0 0 0 4px rgba(39, 158, 254, 0.24), var(--shadow); }
.lyric-item.active.playing-flash { box-shadow: 0 0 0 4px rgba(39, 158, 254, 0.18); }

@keyframes playFlash {
  0% { transform: scale(1); }
  35% { transform: scale(1.008); }
  100% { transform: scale(1); }
}

.toast {
  position: fixed;
  right: 20px;
  bottom: 20px;
  z-index: 20;
  max-width: min(420px, calc(100% - 40px));
  padding: 12px 15px;
  border: 1px solid #23445e;
  border-radius: 9px;
  color: #fff;
  background: #102b40;
  box-shadow: var(--shadow);
}

@media (max-width: 900px) {
  .practice-workspace { grid-template-columns: 1fr; }

  .lyrics-pane {
    height: min(540px, 62vh);
    min-height: 430px;
  }

  .player-box { height: auto; min-height: 0; }
  .native-player { height: auto; aspect-ratio: 16 / 9; }
}

@media (max-width: 720px) {
  .page {
    width: min(100% - 24px, 980px);
    padding: 22px 0 30px;
    gap: 14px;
  }

  .brand-header {
    min-height: auto;
    align-items: flex-start;
    flex-wrap: wrap;
  }

  .brand-mark { width: 50px; height: 50px; border-radius: 12px; }
  .brand-actions { margin-left: auto; }
  .brand-meta { display: none; }
  .brand-tagline { font-size: 13px; }
  .extension-download { min-height: 40px; padding: 0 12px; }
  .extension-download small { display: none; }

  .input-panel,
  .practice-card { padding: 16px; }

  .input-heading { display: block; }
  .input-step { display: block; margin-bottom: 5px; }
  .url-row { grid-template-columns: 1fr; }
  .primary-btn { width: 100%; }

  .song-head { display: grid; }
  .song-head h2 { font-size: 28px; }

  .lyrics-toolbar { display: grid; }
  .lyrics-actions { justify-content: flex-start; }
  .line-editor { padding: 10px; }
  .line-editor p { font-size: 14px; }
  .lyric-item { grid-template-columns: 50px 1fr; }
}

@media (max-width: 520px) {
  .brand-actions { width: 100%; }
  .extension-download { width: 100%; }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    scroll-behavior: auto !important;
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}