:root {
  color-scheme: light;
  --bg: #f5f2ec;
  --panel: rgba(255, 255, 255, 0.82);
  --panel-solid: #fffaf2;
  --text: #251c16;
  --muted: #756b63;
  --line: rgba(44, 31, 20, 0.12);
  --accent: #a85f2b;
  --accent-2: #3b7467;
  --danger: #b13b39;
  --ok: #26734d;
  --shadow: 0 18px 50px rgba(69, 45, 24, 0.12);
  --radius: 22px;
  --mono: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", monospace;
  --sans: ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
}

html[data-theme="dark"] {
  color-scheme: dark;
  --bg: #1b1510;
  --panel: rgba(48, 38, 29, 0.78);
  --panel-solid: #2b2119;
  --text: #fff0d9;
  --muted: #c8b8a1;
  --line: rgba(255, 216, 169, 0.19);
  --accent: #f4a35d;
  --accent-2: #86d0bc;
  --danger: #f0847d;
  --ok: #78ce99;
  --shadow: 0 22px 70px rgba(4, 2, 1, 0.44);
}

* { box-sizing: border-box; }
body {
  margin: 0;
  font-family: var(--sans);
  background:
    radial-gradient(circle at 15% 10%, rgba(168, 95, 43, 0.15), transparent 32%),
    radial-gradient(circle at 75% 0%, rgba(59, 116, 103, 0.14), transparent 28%),
    var(--bg);
  color: var(--text);
  min-height: 100vh;
  overflow: hidden;
}

html[data-theme="dark"] body {
  background:
    radial-gradient(circle at 16% 8%, rgba(244, 163, 93, 0.18), transparent 42%),
    radial-gradient(circle at 82% 10%, rgba(134, 208, 188, 0.1), transparent 38%),
    var(--bg);
}

button, input, select, textarea { font: inherit; }
code, kbd { font-family: var(--mono); }
code {
  background: rgba(128, 100, 72, 0.12);
  padding: 0.08rem 0.35rem;
  border-radius: 0.45rem;
}
kbd {
  border: 1px solid var(--line);
  border-bottom-width: 2px;
  padding: 0.08rem 0.35rem;
  border-radius: 0.35rem;
  background: var(--panel-solid);
}

.topbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 0.75rem;
  min-height: 52px;
  padding: 0.38rem clamp(0.7rem, 2vw, 1rem);
}
.brand { display: flex; gap: 0.65rem; align-items: center; min-width: 0; }
.brand-copy { min-width: 0; }
.logo {
  width: 34px; height: 34px; border-radius: 10px;
  display: grid; place-items: center;
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  color: white; font-weight: 800; font-size: 0.95rem;
  box-shadow: var(--shadow);
  flex: 0 0 auto;
}
h1 {
  font-size: clamp(1rem, 1.7vw, 1.25rem);
  margin: 0;
  letter-spacing: 0;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
h2 { font-size: 1rem; margin: 0 0 0.7rem; }
p { line-height: 1.65; }
.brand p { display: none; }
.top-actions { display: flex; gap: 0.35rem; flex: 0 0 auto; justify-content: flex-end; align-items: center; }
.chapter-select {
  display: block;
  height: 36px;
  padding: 0;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: var(--panel);
  color: var(--text);
  font-size: 0.82rem;
  font-weight: 800;
  overflow: hidden;
}

.chapter-select select {
  width: 7.2rem;
  height: 100%;
  border: 0;
  border-radius: 10px;
  background: var(--panel-solid);
  color: var(--text);
  font-weight: 900;
  outline: none;
  padding: 0 0.55rem;
}

.chapter-select:focus-within {
  border-color: color-mix(in srgb, var(--accent) 58%, var(--line));
}
.icon-btn {
  width: 36px;
  height: 36px;
  display: grid;
  place-items: center;
  padding: 0;
  border-radius: 10px;
}
.icon-btn svg {
  width: 18px;
  height: 18px;
  fill: none;
  stroke: currentColor;
  stroke-width: 2;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.layout {
  display: grid;
  grid-template-columns: minmax(270px, 340px) minmax(380px, 1fr) minmax(270px, 360px);
  gap: 1rem;
  height: calc(100vh - 52px);
  padding: 0.5rem clamp(1rem, 3vw, 1.5rem) 1rem;
  align-items: start;
  overflow: hidden;
}
.panel {
  background: var(--panel);
  backdrop-filter: blur(18px);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}
.sidebar, .rightbar {
  max-height: 100%;
  overflow: auto;
  padding: 0.85rem;
}
.sidebar section, .rightbar section { padding: 0.6rem 0; border-bottom: 1px solid var(--line); }
.sidebar section:first-child, .rightbar section:first-child { padding-top: 0; }
.sidebar section:last-child, .rightbar section:last-child { border-bottom: 0; padding-bottom: 0; }
.trainer {
  max-height: 100%;
  overflow: auto;
  padding: clamp(0.8rem, 2vw, 1.1rem);
}

.hint { color: var(--muted); margin: 0.35rem 0 0.75rem; }
.small { font-size: 0.9rem; }

button, .filepick {
  border: 0;
  background: var(--accent);
  color: white;
  border-radius: 14px;
  padding: 0.72rem 0.95rem;
  cursor: pointer;
  transition: transform 0.12s ease, opacity 0.12s ease, background 0.12s ease;
  text-align: center;
  font-weight: 700;
}
button:hover, .filepick:hover { transform: translateY(-1px); opacity: 0.94; }
button:active, .filepick:active { transform: translateY(0); }
button.ghost, .filepick.secondary {
  background: transparent;
  color: var(--text);
  border: 1px solid var(--line);
}
button.danger { color: var(--danger); }
button:disabled { opacity: 0.45; cursor: not-allowed; transform: none; }
.filepick { display: block; margin: 0.55rem 0; }
.filepick input { display: none; }

.dropzone {
  border: 1.5px dashed var(--line);
  border-radius: 16px;
  padding: 1rem;
  color: var(--muted);
  text-align: center;
  margin: 0.6rem 0;
  background: rgba(128, 100, 72, 0.06);
}
.dropzone.drag { border-color: var(--accent); color: var(--accent); background: rgba(168, 95, 43, 0.1); }

.field { display: grid; gap: 0.35rem; margin: 0.75rem 0; color: var(--muted); font-size: 0.95rem; }
input, select, textarea {
  width: 100%;
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 0.72rem 0.8rem;
  background: var(--panel-solid);
  color: var(--text);
  outline: none;
}
input:focus, select:focus, textarea:focus { border-color: var(--accent); box-shadow: 0 0 0 3px rgba(168, 95, 43, 0.13); }
textarea { resize: vertical; font-family: var(--mono); font-size: 0.92rem; }
.mini-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 0.55rem; margin-top: 0.6rem; }

.stats { display: grid; grid-template-columns: 1fr 1fr; gap: 0.55rem; }
.stats div { border: 1px solid var(--line); border-radius: 16px; padding: 0.7rem; background: rgba(128, 100, 72, 0.06); }
.stats b { display: block; font-size: 1.35rem; color: var(--accent); }
.stats span { color: var(--muted); font-size: 0.85rem; }

.trainer-head { display: flex; justify-content: space-between; gap: 1rem; align-items: flex-start; }
.trainer-head h2 { font-size: 1.35rem; margin-bottom: 0.25rem; }
.badge {
  white-space: nowrap;
  padding: 0.45rem 0.7rem;
  border: 1px solid var(--line);
  border-radius: 999px;
  color: var(--accent-2);
  font-weight: 800;
  background: rgba(59, 116, 103, 0.1);
}
.card {
  margin: 0.8rem 0;
  border: 1px solid var(--line);
  border-radius: calc(var(--radius) + 6px);
  min-height: 230px;
  display: grid;
  align-content: center;
  text-align: center;
  padding: clamp(1rem, 4vw, 2rem);
  background:
    linear-gradient(145deg, rgba(255,255,255,0.52), rgba(255,255,255,0.04)),
    rgba(128, 100, 72, 0.06);
  position: relative;
  overflow: hidden;
}
html[data-theme="dark"] .card { background: transparent; }
.card::before {
  content: "";
  position: absolute;
  width: 180px; height: 180px;
  border-radius: 999px;
  background: rgba(168, 95, 43, 0.12);
  right: -60px; top: -60px;
}

html[data-theme="dark"] .mode-tabs,
html[data-theme="dark"] .chapter-select,
html[data-theme="dark"] .icon-btn,
html[data-theme="dark"] .trainer-stats {
  background: rgba(43, 33, 25, 0.72);
  border-color: rgba(255, 216, 169, 0.18);
  box-shadow: 0 16px 44px rgba(5, 3, 1, 0.26);
}

html[data-theme="dark"] .mode-tabs button.active,
html[data-theme="dark"] .icon-btn.active {
  background: linear-gradient(135deg, #f0a15d, #d97842);
  color: #fff7eb;
}

html[data-theme="dark"] .prompt-main {
  color: #ffeacf;
  text-shadow: 0 12px 36px rgba(244, 163, 93, 0.18);
}
.prompt-meta { color: var(--muted); letter-spacing: 0.12em; text-transform: uppercase; font-size: 0.8rem; }
.prompt-main { font-size: clamp(3.6rem, 10vw, 6.5rem); line-height: 1; font-weight: 800; letter-spacing: 0; margin: 0.3rem 0; }
.prompt-sub { color: var(--muted); font-size: clamp(1rem, 2vw, 1.25rem); }
.copy-code {
  --code-cell-size: minmax(42px, 62px);
  --code-gap: 0.5rem;
  position: relative;
  display: grid;
  grid-template-columns: repeat(4, var(--code-cell-size));
  justify-content: center;
  gap: var(--code-gap);
  margin-top: 0.35rem;
}
.middle-parts-hint {
  position: absolute;
  top: -0.02rem;
  left: calc(100% + var(--code-gap) / 2);
  z-index: 2;
  max-width: min(9rem, 26vw);
  transform: translateX(-50%);
  color: var(--accent-2);
  padding: 0 0.18rem;
  font-weight: 800;
  font-size: 0.9rem;
  line-height: 1.35;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  pointer-events: none;
}
.copy-cell {
  position: relative;
  display: grid;
  width: 100%;
  gap: 0.28rem;
  justify-items: center;
  align-content: start;
}
.copy-cell em {
  min-height: 1.35em;
  color: var(--muted);
  font-style: normal;
  font-weight: 800;
  line-height: 1.1;
}
.copy-cell.has-part em {
  color: var(--accent-2);
}
.copy-code span {
  width: 100%;
  display: grid;
  place-items: center;
  aspect-ratio: 1;
  border: 1px solid var(--line);
  border-radius: 12px;
  background: var(--panel-solid);
  color: var(--accent);
  font-family: var(--mono);
  font-size: 1.45rem;
  font-weight: 800;
  text-transform: uppercase;
  transition: background 0.12s ease, border-color 0.12s ease, color 0.12s ease, transform 0.12s ease;
}

html[data-theme="dark"] .copy-code span {
  background: linear-gradient(180deg, rgba(53, 42, 32, 0.86), rgba(35, 27, 21, 0.9));
  border-color: rgba(255, 216, 169, 0.16);
  color: #ffb36f;
}

html[data-theme="dark"] .copy-code span.current {
  border-color: #f4a35d;
  box-shadow: 0 0 0 3px rgba(244, 163, 93, 0.2), 0 0 28px rgba(244, 163, 93, 0.14);
}
.copy-code span.current {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(168, 95, 43, 0.13);
}
.copy-code span.correct {
  border-color: rgba(38, 115, 77, 0.48);
  background: rgba(38, 115, 77, 0.14);
  color: var(--ok);
  transform: translateY(-1px);
}
.copy-code span.wrong {
  border-color: rgba(177, 59, 57, 0.52);
  background: rgba(177, 59, 57, 0.12);
  color: var(--danger);
}
.copy-cell.masked span {
  color: var(--muted);
  background: rgba(128, 100, 72, 0.08);
  cursor: pointer;
  user-select: none;
  -webkit-user-select: none;
  touch-action: manipulation;
}

html[data-theme="dark"] .copy-cell.masked span {
  background: rgba(47, 39, 32, 0.82);
  color: #cdbca6;
}
.copy-cell.masked span.revealed {
  border-color: rgba(168, 95, 43, 0.58);
  background: var(--panel-solid);
  color: var(--accent);
}

html[data-theme="dark"] .copy-cell.masked span.revealed {
  border-color: rgba(244, 163, 93, 0.82);
  background: #35281f;
  color: #ffb36f;
}
.copy-cell.masked span.correct {
  color: var(--ok);
  background: rgba(38, 115, 77, 0.14);
}
.copy-cell.masked span.wrong {
  color: var(--danger);
  background: rgba(177, 59, 57, 0.12);
}
.code-breakdown {
  display: flex;
  justify-content: center;
  gap: 0.6rem;
  flex-wrap: wrap;
  margin-top: 0.75rem;
  font-size: 0.95rem;
}
.code-breakdown span {
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 0.25rem 0.65rem;
  background: rgba(128, 100, 72, 0.06);
}

html[data-theme="dark"] .code-breakdown span,
html[data-theme="dark"] .shape-hint span {
  background: rgba(43, 33, 25, 0.74);
}
.code-breakdown b {
  margin-left: 0.35rem;
  color: var(--text);
}
.shape-hint {
  margin-top: 0.75rem;
  display: flex;
  justify-content: center;
}
.shape-hint span {
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 0.35rem 0.75rem;
  background: var(--panel-solid);
  color: var(--text);
  font-weight: 800;
}
.component-line {
  margin-top: 0.55rem;
  color: var(--muted);
  font-size: 0.95rem;
}
.pronunciation-hint {
  display: flex;
  justify-content: center;
  gap: 0.45rem;
  flex-wrap: wrap;
  margin-bottom: clamp(0.55rem, 1.4vh, 0.9rem);
  color: var(--muted);
  font-size: clamp(0.82rem, 1.55vh, 0.98rem);
}
.pronunciation-hint span {
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 0.2rem 0.55rem;
  background: rgba(255, 255, 255, 0.52);
}
.root-hint-card {
  width: 100%;
  min-height: 4.7rem;
  margin-top: 0.65rem;
  border: 1px solid var(--line);
  border-radius: 14px;
  background: rgba(255, 255, 255, 0.52);
  padding: 0.48rem 0.55rem;
  display: grid;
  gap: 0.25rem;
  text-align: left;
  align-content: start;
}

html[data-theme="dark"] .root-hint-card {
  background: rgba(54, 44, 35, 0.9);
  border-color: rgba(255, 216, 169, 0.18);
}

html[data-theme="dark"] .root-hint-card strong {
  color: #fff0d9;
}

html[data-theme="dark"] .root-hint-card small {
  color: #d7c6ad;
}
.root-hint-card.placeholder {
  visibility: hidden;
}
.root-hint-card strong {
  color: var(--text);
  font-size: 0.92rem;
}
.root-hint-card small {
  color: var(--muted);
  line-height: 1.45;
}
.answerbar { display: grid; grid-template-columns: 1fr auto; gap: 0.7rem; }
.answerbar.copy-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  overflow: hidden;
  clip-path: inset(50%);
  opacity: 0;
  pointer-events: none;
}
.answerbar input { font-family: var(--mono); font-size: 1.15rem; letter-spacing: 0.06em; }

.hidden-input {
  position: fixed;
  left: -100vw;
  top: 0;
  width: 1px;
  height: 1px;
  opacity: 0;
  pointer-events: none;
}
.feedback {
  margin-top: 0.65rem;
  border-radius: 16px;
  padding: 0.9rem 1rem;
  border: 1px solid var(--line);
  background: var(--panel-solid);
  line-height: 1.6;
}
.feedback.ok { border-color: rgba(38, 115, 77, 0.35); color: var(--ok); background: rgba(38, 115, 77, 0.08); }
.feedback.bad { border-color: rgba(177, 59, 57, 0.35); color: var(--danger); background: rgba(177, 59, 57, 0.08); }
.controls-row { display: flex; flex-wrap: wrap; gap: 0.55rem; margin-top: 0.65rem; }
.helpbox { margin-top: 0.7rem; border-top: 1px solid var(--line); padding-top: 0.65rem; color: var(--muted); }
.helpbox summary { cursor: pointer; color: var(--text); font-weight: 800; }

.searchbar { display: grid; grid-template-columns: 1fr auto; gap: 0.5rem; }
.results, .wrong-list {
  margin-top: 0.75rem;
  max-height: 290px;
  overflow: auto;
  display: grid;
  gap: 0.45rem;
}
.result-item {
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 0.55rem 0.65rem;
  background: rgba(128, 100, 72, 0.06);
  display: grid;
  grid-template-columns: auto 1fr auto;
  align-items: center;
  gap: 0.65rem;
}
.result-char { font-size: 1.65rem; font-weight: 800; }
.result-code { font-family: var(--mono); color: var(--accent); font-weight: 800; }
.result-meta { color: var(--muted); font-size: 0.82rem; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.empty { color: var(--muted); font-size: 0.92rem; }

.footer {
  display: flex;
  justify-content: center;
  gap: 1rem;
  flex-wrap: wrap;
  color: var(--muted);
  font-size: 0.76rem;
  position: fixed;
  left: 0;
  right: 0;
  bottom: 0;
  z-index: 12;
  min-height: 22px;
  padding: 0.18rem 0.5rem;
  background: rgba(245, 242, 236, 0.78);
  backdrop-filter: blur(12px);
}

.footer a,
.footer button {
  color: var(--accent-2);
  text-decoration: none;
}

.footer button {
  border: 0;
  background: transparent;
  padding: 0;
  font-weight: 800;
  cursor: pointer;
}

.toast {
  position: fixed;
  left: 50%; bottom: 1rem;
  transform: translateX(-50%);
  background: var(--text);
  color: var(--bg);
  padding: 0.75rem 1rem;
  border-radius: 999px;
  box-shadow: var(--shadow);
  z-index: 10;
  max-width: min(92vw, 760px);
}

@media (max-width: 1120px) {
  body { overflow: auto; }
  .layout { grid-template-columns: minmax(0, 1fr) minmax(0, 1fr); height: auto; overflow: visible; }
  .trainer { grid-column: 1 / -1; order: -1; max-height: none; }
  .sidebar, .rightbar { max-height: none; }
}
@media (max-width: 760px) {
  body { overflow: auto; }
  .topbar {
    min-height: 46px;
    flex-direction: row;
    align-items: center;
    padding: 0.32rem 0.5rem;
  }
  .brand { gap: 0.5rem; }
  .logo {
    width: 30px;
    height: 30px;
    border-radius: 9px;
    font-size: 0.85rem;
  }
  h1 {
    font-size: 0.95rem;
  }
  .top-actions {
    flex: 0 0 auto;
    gap: 0.35rem;
    justify-content: flex-start;
  }
  .chapter-select {
    height: 32px;
  }
  .chapter-select select {
    width: 6.2rem;
    font-size: 0.78rem;
  }
  .icon-btn {
    width: 32px;
    height: 32px;
    border-radius: 9px;
  }
  .icon-btn svg {
    width: 16px;
    height: 16px;
  }
  .layout {
    grid-template-columns: 1fr;
    gap: 0.7rem;
    padding: 0.45rem 0.65rem 0.9rem;
  }
  .trainer {
    order: -3;
    padding: 0.75rem;
    border-radius: 16px;
  }
  .sidebar {
    order: -2;
    border-radius: 16px;
  }
  .rightbar {
    order: -1;
    border-radius: 16px;
  }
  .sidebar section:first-child,
  .rightbar section:nth-child(3) {
    display: none;
  }
  .footer { padding: 0 1rem 1.2rem; }
  .trainer-head { align-items: center; }
  .trainer-head h2 { font-size: 1.08rem; }
  .trainer-head .hint {
    font-size: 0.86rem;
    margin-bottom: 0;
  }
  .badge {
    padding: 0.32rem 0.5rem;
    font-size: 0.78rem;
  }
  .card {
    min-height: 190px;
    margin: 0.55rem 0;
    padding: 0.85rem;
    border-radius: 18px;
  }
  .card::before {
    width: 120px;
    height: 120px;
  }
  .prompt-main { font-size: clamp(3.2rem, 22vw, 5rem); }
  .prompt-sub { font-size: 0.95rem; }
  .copy-code {
    grid-template-columns: repeat(4, minmax(38px, 52px));
    gap: 0.4rem;
  }
  .copy-code span {
    border-radius: 10px;
    font-size: 1.2rem;
  }
  .code-breakdown {
    gap: 0.4rem;
    font-size: 0.86rem;
  }
  .answerbar { grid-template-columns: 1fr; }
  .answerbar input {
    font-size: 1rem;
    padding: 0.62rem 0.7rem;
  }
  .controls-row {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
  .controls-row button {
    padding: 0.58rem 0.4rem;
    border-radius: 10px;
    font-size: 0.86rem;
  }
  .sidebar section,
  .rightbar section {
    padding: 0.5rem 0;
  }
  .mini-grid { grid-template-columns: 1fr 1fr; }
  input, select, textarea, button, .filepick { border-radius: 10px; }
  .stats { grid-template-columns: repeat(4, minmax(0, 1fr)); }
  .stats div {
    padding: 0.5rem 0.35rem;
    text-align: center;
    border-radius: 10px;
  }
  .stats b { font-size: 1rem; }
  .stats span { font-size: 0.74rem; }
  .results, .wrong-list { max-height: 220px; }
  .result-item {
    grid-template-columns: auto minmax(0, 1fr);
  }
  .result-item button {
    grid-column: 1 / -1;
    padding: 0.48rem;
  }
}

@media (max-width: 420px) {
  .mini-grid,
  .controls-row {
    grid-template-columns: 1fr;
  }
  .stats {
    grid-template-columns: 1fr 1fr;
  }
}

.compact-details { margin-top: 12px; }
.compact-details summary { cursor: pointer; color: var(--muted); font-size: 14px; }
.result-code .pill { margin-left: 6px; }
.pill { display: inline-block; border: 1px solid var(--line); border-radius: 999px; padding: 1px 7px; font-size: 12px; color: var(--muted); }

/* Full-screen typing trainer */
html, body {
  height: 100%;
}

body {
  overflow: hidden;
}

.loading-screen {
  position: fixed;
  inset: 54px 0 22px;
  z-index: 40;
  display: grid;
  place-items: center;
  align-content: center;
  gap: 1rem;
  padding: 1rem;
  background:
    radial-gradient(circle at 42% 38%, rgba(255, 255, 255, 0.45), transparent 30%),
    var(--bg);
  color: var(--text);
  transition: opacity 0.18s ease, visibility 0.18s ease;
}

.loading-mark {
  width: 52px;
  height: 52px;
  border-radius: 15px;
  display: grid;
  place-items: center;
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  color: #fff;
  font-weight: 900;
  box-shadow: var(--shadow);
}

.loading-copy {
  display: grid;
  gap: 0.25rem;
  text-align: center;
}

.loading-copy strong {
  font-size: 1rem;
}

.loading-copy span {
  color: var(--muted);
  font-size: 0.86rem;
}

.loading-bar {
  width: min(280px, 70vw);
  height: 6px;
  overflow: hidden;
  border-radius: 999px;
  background: rgba(128, 100, 72, 0.12);
}

.loading-bar span {
  display: block;
  width: 42%;
  height: 100%;
  border-radius: inherit;
  background: linear-gradient(90deg, var(--accent-2), var(--accent));
  animation: loading-slide 0.95s ease-in-out infinite;
}

.app-ready .loading-screen {
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
}

@keyframes loading-slide {
  0% { transform: translateX(-105%); }
  100% { transform: translateX(245%); }
}

.topbar {
  height: 54px;
  min-height: 54px;
  padding: 0 1rem;
}

.mode-tabs {
  display: grid;
  grid-template-columns: repeat(2, auto);
  gap: 0.2rem;
  padding: 0.2rem;
  border: 1px solid var(--line);
  border-radius: 12px;
  background: var(--panel);
  white-space: nowrap;
}

.mode-tabs button {
  background: transparent;
  color: var(--muted);
  border: 0;
  border-radius: 9px;
  padding: 0.38rem 0.65rem;
  font-size: 0.9rem;
  box-shadow: none;
}

.mode-tabs button.active {
  background: var(--accent);
  color: white;
}

.icon-btn.active {
  color: white;
  background: var(--accent);
  border-color: transparent;
}

.layout {
  display: block;
  height: calc(100dvh - 54px - 22px);
  padding: 0;
  overflow: hidden;
}

.sidebar,
.rightbar {
  display: none;
}

.trainer {
  height: 100%;
  max-height: none;
  overflow: hidden;
  border: 0;
  border-radius: 0;
  box-shadow: none;
  background: transparent;
  backdrop-filter: none;
  display: grid;
  grid-template-rows: auto minmax(0, 1fr) auto auto auto;
  align-items: center;
  padding: clamp(0.7rem, 2vw, 1.2rem) clamp(1rem, 5vw, 4rem);
}

.trainer-head {
  width: min(920px, 100%);
  justify-self: center;
  align-items: center;
}

.trainer-head h2 {
  font-size: clamp(1rem, 2vw, 1.45rem);
}

.trainer-head .hint {
  display: none;
}

.badge {
  padding: 0.35rem 0.6rem;
  font-size: 0.86rem;
}

.card {
  width: min(920px, 100%);
  min-height: 0;
  height: 100%;
  justify-self: center;
  margin: 0;
  border: 0;
  border-radius: 0;
  box-shadow: none;
  background: transparent;
  padding: clamp(0.5rem, 3vh, 2rem) 0;
  transform: translateY(clamp(1.5rem, 5vh, 4rem));
}

.card::before {
  display: none;
}

.prompt-meta {
  display: none;
}

.prompt-main {
  font-size: clamp(4.8rem, 18vh, 12rem);
  margin: 0 0 clamp(0.7rem, 2vh, 1.2rem);
}

.prompt-main.word-prompt {
  width: min(96vw, 980px);
  max-width: 100%;
  white-space: nowrap;
  overflow: visible;
  text-align: center;
  font-size: clamp(4.1rem, 15vh, 9rem);
}

.prompt-main.word-len-4 { font-size: clamp(3.6rem, 13vh, 7.6rem); }
.prompt-main.word-len-5 { font-size: clamp(3.05rem, 11vh, 6.4rem); }
.prompt-main.word-len-6 { font-size: clamp(2.55rem, 9.4vh, 5.4rem); }
.prompt-main.word-len-7,
.prompt-main.word-len-8 { font-size: clamp(2.15rem, 7.8vh, 4.55rem); }

.copy-code {
  --code-cell-size: clamp(4.2rem, 10vh, 6.8rem);
  --code-gap: clamp(0.55rem, 1.6vw, 1rem);
  grid-template-columns: repeat(4, var(--code-cell-size));
  gap: var(--code-gap);
  margin-top: clamp(1.1rem, 3vh, 2.4rem);
}

.copy-cell {
  gap: clamp(0.22rem, 0.7vh, 0.42rem);
}

.copy-cell em {
  font-size: clamp(0.95rem, 2.1vh, 1.35rem);
}

.copy-code span {
  border-radius: 14px;
  font-size: clamp(1.7rem, 4vh, 2.55rem);
}

.code-breakdown {
  margin-top: clamp(0.75rem, 2vh, 1.3rem);
  font-size: clamp(0.92rem, 1.7vh, 1.08rem);
}

.code-breakdown span,
.shape-hint span {
  background: rgba(255,255,255,0.58);
}

.component-line {
  font-size: clamp(0.92rem, 1.8vh, 1.1rem);
}

.answerbar.copy-hidden {
  position: fixed;
  left: -100vw;
  top: 0;
}

.feedback,
.controls-row,
.helpbox {
  display: none;
}

.trainer-stats {
  width: min(760px, 100%);
  justify-self: center;
  align-self: end;
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 0.8rem;
  border: 1px solid var(--line);
  border-radius: 16px;
  background: var(--panel);
  box-shadow: var(--shadow);
  padding: 0.75rem clamp(0.75rem, 2vw, 1.4rem);
}

.trainer-head {
  display: none;
}

.modal[hidden] {
  display: none;
}

.modal {
  position: fixed;
  inset: 0;
  z-index: 50;
  display: grid;
  place-items: center;
  padding: 1rem;
}

.modal-backdrop {
  position: absolute;
  inset: 0;
  background: rgba(24, 18, 13, 0.38);
}

html[data-theme="dark"] .modal-backdrop {
  background: rgba(10, 7, 4, 0.58);
}

.modal-panel {
  position: relative;
  width: min(680px, 100%);
  max-height: min(78vh, 720px);
  overflow: auto;
  border: 1px solid var(--line);
  border-radius: 18px;
  background: var(--panel-solid);
  color: var(--text);
  box-shadow: var(--shadow);
  isolation: isolate;
}

.modal-head {
  position: sticky;
  top: 0;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  padding: 0.85rem 1rem;
  border-bottom: 1px solid var(--line);
  background: var(--panel-solid);
}

.modal-head h2 {
  margin: 0;
}

.modal-body {
  padding: 1rem;
  color: var(--muted);
  background: var(--panel-solid);
}

.modal-body a {
  color: var(--accent-2);
}

.modal-body li {
  margin: 0.4rem 0;
}

.settings-panel {
  width: min(460px, 100%);
}

.settings-body {
  display: grid;
  gap: 1rem;
}

.setting-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 0.85rem 0.9rem;
  background: var(--panel-solid);
}

.setting-row span {
  display: grid;
  gap: 0.25rem;
}

.setting-row strong,
.settings-group h3 {
  color: var(--text);
}

.setting-row small {
  line-height: 1.45;
}

.setting-row input {
  width: 1.2rem;
  height: 1.2rem;
  accent-color: var(--accent);
  flex: 0 0 auto;
}

html[data-theme="dark"] .modal-panel,
html[data-theme="dark"] .modal-head,
html[data-theme="dark"] .modal-body,
html[data-theme="dark"] .settings-body,
html[data-theme="dark"] .setting-row {
  background: #2b2119;
}

html[data-theme="dark"] .modal-panel {
  border-color: rgba(255, 216, 169, 0.22);
}

html[data-theme="dark"] .setting-row {
  background: #30251d;
}

.settings-group {
  border-top: 1px solid var(--line);
  padding-top: 1rem;
}

.settings-group h3 {
  margin: 0 0 0.7rem;
  font-size: 0.95rem;
}

.settings-actions {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.65rem;
}

.settings-wide-action {
  grid-column: 1 / -1;
}

.compact-filepick {
  margin: 0;
}

.trainer-stats div {
  text-align: center;
}

.trainer-stats b {
  display: block;
  color: var(--accent);
  font-size: clamp(1.1rem, 2.4vh, 1.55rem);
}

.trainer-stats span {
  color: var(--muted);
  font-size: clamp(0.72rem, 1.45vh, 0.88rem);
}

html[data-theme="dark"] .card {
  background: transparent;
}

html[data-theme="dark"] .trainer-stats {
  background: rgba(39, 29, 22, 0.84);
}

html[data-theme="dark"] .footer {
  background: linear-gradient(90deg, rgba(27, 21, 16, 0), rgba(49, 38, 29, 0.34), rgba(27, 21, 16, 0));
}

html[data-theme="dark"] .footer a,
html[data-theme="dark"] .footer button {
  color: #86d0bc;
}

@media (max-width: 760px) {
  body {
    overflow: hidden;
  }

  .topbar {
    height: 46px;
    min-height: 46px;
    padding: 0 0.45rem;
  }

  .mode-tabs button {
    padding: 0.32rem 0.38rem;
    font-size: 0.78rem;
  }

  .chapter-select {
    height: 31px;
  }

  .chapter-select select {
    width: 6.2rem;
  }

  .icon-btn {
    width: 30px;
    height: 31px;
  }

  .layout {
    height: calc(100dvh - 46px - 22px);
    padding: 0;
  }

  .trainer {
    grid-template-rows: minmax(0, 1fr) auto auto auto;
    padding: 0.55rem 0.75rem 0.75rem;
  }

  .trainer-head {
    align-items: flex-start;
  }

  .trainer-head .hint {
    font-size: 0.78rem;
  }

  .badge {
    font-size: 0.72rem;
  }

  .prompt-main {
    font-size: clamp(4.1rem, 18vh, 8rem);
  }

  .prompt-main.word-prompt {
    width: 100vw;
    max-width: 100vw;
    font-size: clamp(3rem, 15vw, 5rem);
  }

  .prompt-main.word-len-4 { font-size: clamp(2.6rem, 13vw, 4.4rem); }
  .prompt-main.word-len-5 { font-size: clamp(2.2rem, 11vw, 3.7rem); }
  .prompt-main.word-len-6 { font-size: clamp(1.9rem, 9.4vw, 3.1rem); }
  .prompt-main.word-len-7,
  .prompt-main.word-len-8 { font-size: clamp(1.6rem, 8vw, 2.65rem); }

  .card {
    transform: translateY(clamp(1rem, 4vh, 2.2rem));
  }

  .copy-code {
    --code-cell-size: clamp(3.45rem, 17vw, 4.75rem);
    --code-gap: clamp(0.32rem, 1.8vw, 0.55rem);
    grid-template-columns: repeat(4, var(--code-cell-size));
    gap: var(--code-gap);
    margin-top: clamp(0.8rem, 2.4vh, 1.5rem);
  }

  .middle-parts-hint {
    max-width: 5.4rem;
    font-size: 0.72rem;
    padding: 0.06rem 0.35rem;
  }

  .copy-cell em {
    font-size: 0.9rem;
  }

  .copy-code span {
    border-radius: 13px;
    font-size: clamp(1.35rem, 5.5vw, 1.8rem);
  }

  .code-breakdown {
    gap: 0.35rem;
    font-size: 0.82rem;
  }

  .component-line {
    font-size: 0.82rem;
  }

  .pronunciation-hint {
    font-size: 0.76rem;
    margin-bottom: 0.45rem;
  }

  .root-hint-card {
    min-height: 4rem;
    margin-top: 0.45rem;
    padding: 0.38rem 0.42rem;
    border-radius: 11px;
  }

  .root-hint-card strong {
    font-size: 0.76rem;
  }

  .root-hint-card small {
    font-size: 0.68rem;
  }

  .trainer-stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 0.35rem;
    padding: 0.55rem 0.45rem;
    border-radius: 12px;
  }

  .footer {
    gap: 0.35rem;
    font-size: 0.64rem;
    min-height: 22px;
  }
}

@media (max-width: 420px) {
  h1 {
    max-width: 8.2em;
  }

  .trainer-stats span {
    font-size: 0.68rem;
  }
}