:root {
  color-scheme: light;
  --bg: #f5f7f8;
  --panel: #ffffff;
  --text: #17201d;
  --muted: #5f6b66;
  --border: #d8dfdd;
  --primary: #246b4f;
  --primary-strong: #174d38;
  --accent: #265f86;
  --warning: #a45b18;
  --danger: #b33c35;
  --shadow: 0 14px 35px rgba(23, 32, 29, 0.08);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  letter-spacing: 0;
}

button,
input,
textarea {
  font: inherit;
}

button {
  min-height: 40px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: #ffffff;
  color: var(--text);
  cursor: pointer;
}

button:hover {
  border-color: var(--accent);
}

button:disabled {
  cursor: not-allowed;
  opacity: 0.55;
}

.primary {
  border-color: var(--primary);
  background: var(--primary);
  color: #ffffff;
}

.primary:hover {
  border-color: var(--primary-strong);
  background: var(--primary-strong);
}

.app-shell {
  width: min(1440px, 100%);
  margin: 0 auto;
  padding: 24px;
}

.topbar {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 24px;
  align-items: end;
  padding: 4px 0 20px;
}

h1,
h2,
p {
  margin: 0;
}

h1 {
  font-size: clamp(28px, 4vw, 44px);
  line-height: 1.1;
}

h2 {
  font-size: 16px;
  line-height: 1.3;
}

.topbar p {
  margin-top: 8px;
  color: var(--muted);
}

.stats-grid {
  display: grid;
  grid-template-columns: minmax(96px, 1fr);
  gap: 10px;
}

.stat {
  min-width: 96px;
  padding: 12px 14px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--panel);
}

.stat span {
  display: block;
  color: var(--muted);
  font-size: 12px;
}

.stat strong {
  display: block;
  margin-top: 4px;
  font-size: 24px;
}

.workspace {
  display: grid;
  grid-template-columns: minmax(320px, 390px) minmax(0, 1fr);
  gap: 18px;
  align-items: start;
}

.side-panel,
.study-panel {
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--panel);
  box-shadow: var(--shadow);
}

.side-panel {
  overflow: hidden;
}

.panel-section {
  padding: 18px;
  border-bottom: 1px solid var(--border);
}

.panel-section:last-child {
  border-bottom: 0;
}

.stack,
.import-block {
  display: grid;
  gap: 10px;
  margin-top: 12px;
}

label {
  display: grid;
  gap: 6px;
  color: var(--muted);
  font-size: 13px;
}

input,
textarea {
  width: 100%;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: #ffffff;
  color: var(--text);
  outline: none;
}

input {
  height: 40px;
  padding: 0 12px;
}

textarea {
  resize: vertical;
  min-height: 84px;
  padding: 10px 12px;
  line-height: 1.45;
}

input:focus,
textarea:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(38, 95, 134, 0.14);
}

.report {
  margin-top: 12px;
  color: var(--muted);
  font-size: 13px;
  line-height: 1.5;
}

.report strong {
  color: var(--text);
}

.report.error {
  color: var(--danger);
}

.section-title-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}

#wordCountBadge {
  color: var(--muted);
  font-size: 13px;
}

.search {
  margin-top: 12px;
}

.word-list {
  display: grid;
  max-height: 360px;
  margin-top: 12px;
  overflow: auto;
  border: 1px solid var(--border);
  border-radius: 8px;
}

.word-row {
  display: grid;
  gap: 3px;
  padding: 10px 12px;
  border-bottom: 1px solid var(--border);
}

.word-row:last-child {
  border-bottom: 0;
}

.word-row strong {
  font-size: 15px;
}

.word-row span {
  color: var(--muted);
  font-size: 12px;
  line-height: 1.35;
}

.study-panel {
  min-height: 640px;
  padding: 22px;
}

.mode-switch {
  display: inline-grid;
  grid-template-columns: repeat(2, 112px);
  gap: 4px;
  padding: 4px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: #edf2f1;
}

.mode-button {
  min-height: 36px;
  border: 0;
  background: transparent;
}

.mode-button.active {
  background: #ffffff;
  color: var(--primary);
  box-shadow: 0 2px 8px rgba(23, 32, 29, 0.08);
}

.empty-state,
.study-card {
  margin-top: 22px;
}

.empty-state {
  display: grid;
  min-height: 420px;
  place-content: center;
  gap: 8px;
  color: var(--muted);
  text-align: center;
}

.empty-state h2 {
  color: var(--text);
  font-size: 22px;
}

.study-card {
  display: grid;
  gap: 18px;
}

.study-meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  color: var(--muted);
}

.study-meta button {
  min-width: 88px;
}

.word-focus {
  overflow-wrap: anywhere;
  font-size: clamp(44px, 8vw, 82px);
  font-weight: 750;
  line-height: 1.02;
}

.phonetic {
  min-height: 28px;
  color: var(--accent);
  font-size: 18px;
}

.answer-toggle {
  width: min(220px, 100%);
}

.meaning {
  min-height: 96px;
  padding: 18px;
  border-left: 4px solid var(--primary);
  background: #eef5f2;
  line-height: 1.65;
}

.action-row,
.spell-form {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
}

.prompt-label {
  color: var(--muted);
}

.quiz-meaning {
  min-height: 130px;
}

.quiz-result {
  min-height: 28px;
  color: var(--muted);
  line-height: 1.5;
}

.quiz-result.correct {
  color: var(--primary);
}

.quiz-result.wrong {
  color: var(--danger);
}

.hidden {
  display: none !important;
}

@media (max-width: 920px) {
  .app-shell {
    padding: 16px;
  }

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

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

  .study-panel {
    min-height: 520px;
  }
}

@media (max-width: 560px) {
  .app-shell {
    padding: 12px;
  }

  .topbar {
    gap: 14px;
  }

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

  .workspace {
    gap: 12px;
  }

  .panel-section,
  .study-panel {
    padding: 14px;
  }

  .mode-switch,
  .action-row,
  .spell-form {
    grid-template-columns: 1fr;
  }

  .mode-switch {
    width: 100%;
  }

  .word-focus {
    font-size: 42px;
  }
}