:root {
  --bg: #f5f7f8;
  --surface: #ffffff;
  --surface-soft: #f0f5f3;
  --ink: #18201f;
  --ink-2: #4a5552;
  --muted: #7b8681;
  --line: #dce4e1;
  --line-strong: #b9c8c2;
  --green: #1f7a5a;
  --green-soft: #dff1e9;
  --blue: #2d6cdf;
  --blue-soft: #e6eefc;
  --coral: #b85c45;
  --coral-soft: #fae7df;
  --amber: #a36f12;
  --amber-soft: #f7edcf;
  --shadow: 0 14px 42px rgba(24, 32, 31, 0.08);
  --radius: 8px;
  --font: "Noto Sans SC", "PingFang SC", "Microsoft YaHei", -apple-system, BlinkMacSystemFont, system-ui, sans-serif;
}

* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  min-height: 100%;
}

body {
  background: var(--bg);
  color: var(--ink);
  font-family: var(--font);
  font-size: 15px;
  line-height: 1.6;
}

button,
input,
textarea {
  font: inherit;
}

button {
  cursor: pointer;
}

.app-shell {
  width: min(1440px, 100%);
  margin: 0 auto;
  padding: 22px;
}

.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  margin-bottom: 18px;
}

.eyebrow {
  margin: 0 0 2px;
  color: var(--muted);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
}

h1,
h2,
h3,
p {
  margin-top: 0;
}

h1 {
  margin-bottom: 0;
  font-size: 30px;
  line-height: 1.2;
  letter-spacing: 0;
}

h2 {
  margin-bottom: 0;
  font-size: 17px;
}

h3 {
  margin-bottom: 12px;
  color: var(--ink-2);
  font-size: 13px;
}

.topbar-actions,
.edit-actions,
.review-actions,
.recall-actions,
.sentence-controls {
  display: flex;
  align-items: center;
  gap: 8px;
}

.download-btn,
.download-panel-btn {
  display: inline-grid;
  place-items: center;
  min-height: 38px;
  padding: 0 14px;
  border-radius: var(--radius);
  background: var(--green);
  color: #fff;
  font-weight: 800;
  text-decoration: none;
}

.download-panel {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  margin-bottom: 16px;
  padding: 16px;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.download-panel h2 {
  margin-bottom: 4px;
}

.download-panel p {
  margin-bottom: 0;
  color: var(--ink-2);
}

.download-panel-btn {
  min-width: 132px;
}

.workspace {
  display: grid;
  grid-template-columns: minmax(280px, 340px) minmax(420px, 1fr) minmax(260px, 310px);
  gap: 16px;
  align-items: start;
}

.library-panel,
.study-panel,
.review-panel {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.library-panel,
.review-panel {
  padding: 16px;
}

.study-panel {
  min-height: calc(100vh - 112px);
  padding: 16px;
}

.panel-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 14px;
}

.field {
  display: grid;
  gap: 7px;
  margin-bottom: 12px;
}

.field span,
.density-control span {
  color: var(--ink-2);
  font-size: 12px;
  font-weight: 700;
}

input,
textarea,
select {
  width: 100%;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  color: var(--ink);
  background: #fbfcfc;
  outline: none;
}

input:focus,
textarea:focus {
  border-color: var(--green);
  box-shadow: 0 0 0 3px var(--green-soft);
}

input {
  height: 42px;
  padding: 0 12px;
}

textarea {
  min-height: 250px;
  padding: 12px;
  resize: vertical;
}

.text-field textarea {
  min-height: 315px;
}

.primary-btn,
.ghost-btn,
.small-btn,
.icon-btn,
.file-btn,
.modebar button {
  border: 1px solid transparent;
  border-radius: var(--radius);
  min-height: 38px;
  padding: 0 12px;
  font-weight: 700;
}

.primary-btn {
  background: var(--green);
  color: #fff;
}

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

.small-btn,
.icon-btn {
  background: #f7faf9;
  color: var(--ink-2);
  border-color: var(--line);
}

.file-btn {
  display: inline-grid;
  place-items: center;
  background: var(--surface-soft);
  color: var(--ink-2);
  border-color: var(--line);
}

.file-btn input {
  position: absolute;
  width: 1px;
  height: 1px;
  opacity: 0;
  pointer-events: none;
}

.icon-btn {
  width: 42px;
  padding: 0;
}

.primary-btn:hover,
.small-btn:hover,
.ghost-btn:hover,
.icon-btn:hover,
.file-btn:hover,
.modebar button:hover {
  filter: brightness(0.98);
  border-color: var(--line-strong);
}

.passage-stats {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 8px;
  margin: 14px 0;
}

.stat-box {
  min-height: 58px;
  padding: 9px;
  background: var(--surface-soft);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.stat-box b {
  display: block;
  font-size: 18px;
  line-height: 1.2;
}

.stat-box span {
  color: var(--muted);
  font-size: 11px;
}

.passage-list {
  display: grid;
  gap: 8px;
  max-height: 270px;
  overflow: auto;
}

.passage-card {
  display: grid;
  gap: 4px;
  width: 100%;
  padding: 10px;
  background: #fbfcfc;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  text-align: left;
}

.passage-card[aria-current="true"] {
  border-color: var(--green);
  background: var(--green-soft);
}

.passage-card b {
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.passage-card span {
  color: var(--muted);
  font-size: 12px;
}

.modebar {
  display: grid;
  grid-template-columns: repeat(6, minmax(0, 1fr));
  gap: 8px;
  margin-bottom: 12px;
}

.modebar button {
  background: #f7faf9;
  color: var(--ink-2);
  border-color: var(--line);
}

.modebar button[aria-selected="true"] {
  background: var(--blue);
  color: #fff;
  border-color: var(--blue);
}

.controls {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 12px;
  padding: 10px;
  background: #fbfcfc;
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.density-control {
  display: grid;
  grid-template-columns: auto minmax(110px, 240px) 44px;
  align-items: center;
  gap: 10px;
}

.density-control input {
  height: auto;
  padding: 0;
  accent-color: var(--green);
}

.voice-panel {
  display: grid;
  gap: 10px;
  margin-bottom: 12px;
  padding: 10px;
  background: #fbfcfc;
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.voice-actions {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 8px;
}

.voice-actions span {
  color: var(--muted);
  font-size: 12px;
}

.voice-result {
  min-height: 42px;
  padding: 10px;
  background: var(--surface-soft);
  border-radius: var(--radius);
  color: var(--ink-2);
  white-space: pre-wrap;
}

.voice-result b {
  color: var(--green);
}

.sentence-controls span {
  color: var(--muted);
  min-width: 58px;
  text-align: center;
}

.study-surface {
  min-height: 430px;
  padding: 26px;
  background: #fbfcfc;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow-wrap: anywhere;
}

.original-text {
  margin: 0;
  white-space: pre-wrap;
  font-size: 21px;
  line-height: 2;
}

.token-flow {
  display: flex;
  align-items: flex-start;
  flex-wrap: wrap;
  gap: 8px;
}

.token {
  min-height: 32px;
  padding: 3px 8px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: #fff;
  font-size: 20px;
  line-height: 1.45;
}

.token.punctuation {
  color: var(--muted);
  border-color: transparent;
  background: transparent;
  padding-inline: 1px;
}

.token.hidden-word {
  min-width: 42px;
  color: transparent;
  background: var(--coral-soft);
  border-color: #efbba9;
  user-select: none;
}

.token.hidden-word::after {
  content: "";
  display: block;
  height: 2px;
  margin-top: 14px;
  background: var(--coral);
}

.token.initial-token {
  background: var(--blue-soft);
  border-color: #bdd0f8;
}

.sentence-card {
  display: grid;
  gap: 16px;
  max-width: 820px;
}

.sentence-card .sentence-text {
  margin: 0;
  font-size: 28px;
  line-height: 1.9;
}

.sentence-neighbor {
  color: var(--muted);
  font-size: 14px;
}

.empty-state {
  display: grid;
  place-items: center;
  min-height: 320px;
  color: var(--muted);
  text-align: center;
}

.recall-panel {
  margin-top: 12px;
  padding: 14px;
  background: #fbfcfc;
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.recall-panel textarea {
  min-height: 150px;
}

.recall-result {
  margin-top: 12px;
  padding: 12px;
  background: var(--surface-soft);
  border-radius: var(--radius);
  color: var(--ink-2);
}

.answer-block {
  margin-top: 10px;
  padding: 10px;
  border-left: 3px solid var(--green);
  background: #fff;
  white-space: pre-wrap;
}

.review-score {
  display: grid;
  grid-template-columns: 78px 1fr;
  gap: 12px;
  align-items: center;
  margin-bottom: 14px;
}

.score-ring {
  display: grid;
  place-items: center;
  width: 78px;
  height: 78px;
  border-radius: 50%;
  background: conic-gradient(var(--green) 0deg, var(--line) 0deg);
  color: var(--ink);
  font-weight: 800;
}

#reviewMeta {
  margin: 4px 0 0;
  color: var(--muted);
  font-size: 12px;
}

#masteryBadge {
  padding: 4px 8px;
  background: var(--amber-soft);
  border-radius: 999px;
  color: var(--amber);
  font-size: 12px;
  font-weight: 800;
}

.queue-section,
.tip-section {
  margin-top: 18px;
  padding-top: 16px;
  border-top: 1px solid var(--line);
}

.review-queue {
  display: grid;
  gap: 8px;
}

.queue-item {
  width: 100%;
  padding: 9px 10px;
  background: #fbfcfc;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  color: var(--ink-2);
  text-align: left;
}

.queue-item span {
  display: block;
  color: var(--muted);
  font-size: 11px;
}

.tip-section ul {
  margin: 0;
  padding-left: 18px;
  color: var(--ink-2);
}

.tip-section li {
  margin-bottom: 8px;
}

@media (max-width: 1120px) {
  .workspace {
    grid-template-columns: 320px minmax(0, 1fr);
  }

  .review-panel {
    grid-column: 1 / -1;
  }
}

@media (max-width: 760px) {
  .app-shell {
    padding: 14px;
  }

  .topbar {
    align-items: flex-start;
  }

  .topbar-actions {
    flex-wrap: wrap;
    justify-content: flex-end;
  }

  .download-panel {
    align-items: stretch;
    flex-direction: column;
  }

  h1 {
    font-size: 25px;
  }

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

  .study-panel {
    min-height: auto;
  }

  .modebar {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .controls {
    align-items: stretch;
    flex-direction: column;
  }

  .voice-actions {
    align-items: stretch;
    flex-direction: column;
  }

  .density-control {
    grid-template-columns: auto 1fr 44px;
  }

  .study-surface {
    min-height: 340px;
    padding: 18px;
  }

  .original-text,
  .token {
    font-size: 18px;
  }

  .sentence-card .sentence-text {
    font-size: 22px;
  }
}