:root {
  --paper: #f4efe6;
  --ink: #1c1915;
  --muted: #6e665c;
  --line: #d9d1c4;
  --card: #fbf7f0;
  --accent: #243f36;
  --correct: #2c4a3e;
  --wrong: #8a2b2b;
  --nail-1: #1a9b3c;
  --nail-2: #e8a400;
  --nail-3: #e33a2c;
}

* {
  box-sizing: border-box;
}

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

body {
  background: var(--paper);
  color: var(--ink);
  font-family: "Avenir Next", "PingFang SC", "Hiragino Sans GB", sans-serif;
}

a {
  color: inherit;
}

.page {
  width: min(640px, calc(100% - 40px));
  margin: 0 auto;
  padding: 28px 0 80px;
}

.masthead {
  position: sticky;
  top: 0;
  z-index: 5;
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: baseline;
  gap: 10px 14px;
  margin: -8px 0 28px;
  padding: 14px 0 12px;
  background: var(--paper);
  border-bottom: 1px solid var(--line);
  color: var(--ink);
  font-size: 15px;
}

.masthead button {
  appearance: none;
  margin: 0;
  padding: 0;
  border: 0;
  background: none;
  font: inherit;
  color: inherit;
  cursor: pointer;
}

.brand {
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

.nav {
  display: flex;
  flex-wrap: wrap;
  gap: 12px 18px;
}

.nav button {
  color: var(--muted);
}

.nav button.on {
  color: var(--ink);
  font-weight: 600;
  box-shadow: inset 0 -2px 0 var(--ink);
}

.quiet {
  color: var(--muted);
  text-decoration: none;
}

.back {
  margin: 0 0 16px;
}

.back button {
  appearance: none;
  padding: 0;
  border: 0;
  background: none;
  color: var(--muted);
  font: inherit;
  font-size: 14px;
  cursor: pointer;
}

.back button::before {
  content: "← ";
}

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

.kicker {
  margin: 0 0 8px;
  color: var(--muted);
  font-size: 14px;
}

h1 {
  margin: 0 0 18px;
  font-size: clamp(28px, 5vw, 40px);
  font-weight: 560;
  letter-spacing: -0.03em;
  line-height: 1.15;
}

.lead,
.hint,
.meta {
  color: var(--muted);
  line-height: 1.6;
}

.lead {
  margin: 0 0 22px;
}

.picker {
  display: grid;
  gap: 10px;
  margin: 0 0 22px;
}

.chips {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.chip {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 12px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: var(--card);
  color: var(--ink);
  font-size: 14px;
}

.chip[data-exam]::before {
  content: "";
  width: 0.7em;
  height: 0.7em;
  border: 1.5px solid currentColor;
  border-radius: 3px;
  opacity: 0.55;
}

.chip[data-exam].on::before {
  content: "";
  background: currentColor;
  opacity: 1;
  box-shadow: inset 0 0 0 1.5px var(--accent);
}

.chip.on {
  border-color: var(--accent);
  background: var(--accent);
  color: #f6f1e8;
}

.hint {
  margin: 22px 0 0;
  color: #9a9288;
  font-size: 12px;
  line-height: 1.7;
}

.hint.under-actions {
  margin-top: 12px;
}

.stats {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 18px;
  margin: 0 0 24px;
  padding: 14px 0;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  color: var(--muted);
  font-size: 14px;
}

.stats strong {
  color: var(--ink);
  font-weight: 560;
}

.board-label {
  margin: 0 0 8px;
  color: var(--muted);
  font-size: 13px;
}

.chart {
  margin: 0 0 24px;
  padding: 14px 0 16px;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.legend {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 16px;
  margin: 0 0 14px;
  color: var(--muted);
  font-size: 13px;
}

.legend span {
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

.swatch,
.legend i {
  display: inline-block;
  width: 0.7em;
  height: 0.7em;
  border-radius: 2px;
}

.swatch.learned,
.seg.learned {
  background: var(--accent);
}

.swatch.hard,
.seg.hard {
  background: #e8a400;
}

.swatch.notebook,
.seg.notebook {
  background: #d4483a;
}

.swatch.fresh,
.seg.fresh {
  background: #ddd4c6;
}

.bars {
  display: grid;
  gap: 12px;
}

.bar-row {
  display: grid;
  grid-template-columns: 3em 1fr;
  gap: 4px 10px;
  align-items: center;
  opacity: 0.42;
}

.bar-row.on {
  opacity: 1;
}

.bar-row.overall {
  padding-bottom: 6px;
  margin-bottom: 4px;
  border-bottom: 1px dashed var(--line);
}

.bar-name {
  font-size: 14px;
}

.bar-name.overall {
  font-weight: 600;
}

.bar-track {
  height: 16px;
  border-radius: 999px;
  background: #efe8dc;
  overflow: hidden;
}

.bar {
  display: flex;
  height: 100%;
  min-width: 8px;
  overflow: hidden;
  border-radius: 999px;
}

.seg {
  display: block;
  height: 100%;
}

.seg.learned:not(.empty),
.seg.hard:not(.empty),
.seg.notebook:not(.empty) {
  min-width: 5px;
}

.bar-meta {
  grid-column: 2;
  color: var(--muted);
  font-size: 12px;
}

@media (max-width: 640px) {
  .bar-row {
    grid-template-columns: 2.6em 1fr;
  }
}

.actions {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 12px;
}

.actions.equal {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
}

.actions.equal .btn {
  text-align: center;
}

.actions.home {
  display: grid;
  grid-template-columns: 1fr 1fr;
}

.actions.home .btn {
  text-align: center;
}

body.browse-on {
  background: #0a0a0a;
  color: #f5f5f5;
  overflow: hidden;
}

.browse-page {
  position: fixed;
  inset: 0;
  display: flex;
  flex-direction: column;
  outline: none;
  cursor: pointer;
}

.browse-back {
  appearance: none;
  position: absolute;
  top: 18px;
  left: 20px;
  z-index: 2;
  margin: 0;
  padding: 0;
  border: 0;
  background: none;
  color: #a3a3a3;
  font: inherit;
  font-size: 15px;
  cursor: pointer;
}

.browse-back:hover {
  color: #fff;
}

.browse-count {
  position: absolute;
  top: 20px;
  right: 22px;
  margin: 0;
  color: #737373;
  font-size: 13px;
}

.browse-empty {
  margin: auto;
  color: #a3a3a3;
  font-size: 18px;
}

.flash {
  display: flex;
  flex-direction: column;
  flex: 1;
  width: 100%;
  min-height: 0;
  padding: 72px 8vw 24px;
  overflow-x: hidden;
  overflow-y: auto;
  overscroll-behavior: contain;
  cursor: pointer;
}

.flash-word {
  font-family: "Iowan Old Style", Palatino, "Songti SC", serif;
  font-size: clamp(48px, 9vw, 92px);
  font-weight: 650;
  line-height: 1.08;
  color: #fff;
}

.flash-ipa {
  margin-top: 12px;
  color: #a3a3a3;
  font-family: "Lucida Grande", Menlo, "PingFang SC", sans-serif;
  font-size: clamp(18px, 2.4vw, 26px);
}

.flash-exams {
  margin-top: 10px;
  color: #525252;
  font-size: 13px;
  letter-spacing: 0.06em;
}

.flash-ipa:empty,
.flash-exams:empty,
.flash-example:empty {
  display: none;
}

.flash-reveal {
  display: flex;
  flex-direction: column;
  gap: 18px;
  margin-top: 36px;
  opacity: 0;
  transform: translateY(12px);
  transition: opacity 0.35s ease, transform 0.35s ease;
}

.flash.open .flash-reveal {
  opacity: 1;
  transform: none;
}

.flash-meaning {
  font-size: clamp(22px, 3vw, 32px);
  line-height: 1.45;
  color: #f5f5f5;
}

.flash-example,
.flash-more,
.flash-extra {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.flash-example,
.flash-line {
  color: #a3a3a3;
  font-size: clamp(16px, 2vw, 22px);
  line-height: 1.5;
}

.flash-example:empty,
.flash-more:empty {
  display: none;
}

.flash-more {
  gap: 18px;
}

.flash-extra {
  gap: 8px;
}

.flash-k {
  color: #737373;
  font-size: clamp(16px, 2vw, 22px);
  line-height: 1.5;
}

.flash-zh {
  color: #8a8a8a;
}

.flash-line em {
  font-style: normal;
  color: #8a8a8a;
}

.flash-tools {
  margin-top: auto;
  padding-top: 32px;
}

.flash-known {
  appearance: none;
  padding: 8px 16px;
  border: 1px solid #d4d4d4;
  border-radius: 5px;
  background: transparent;
  color: #f5f5f5;
  font: inherit;
  font-size: 15px;
  cursor: pointer;
}

.flash-known:hover {
  background: #fff;
  color: #0a0a0a;
}

.browse-on .nail::after {
  box-shadow: inset 0 0 0 1.5px #737373;
}

.browse-on .nail-set:hover .nail.on::after {
  box-shadow: inset 0 0 0 1.5px #737373;
}

.browse-seek-wrap {
  flex: 0 0 auto;
  padding: 8px 8vw 28px;
  background: #0a0a0a;
  cursor: default;
}

.browse-seek {
  appearance: none;
  display: block;
  width: 100%;
  height: 28px;
  margin: 0;
  background: transparent;
  cursor: pointer;
}

.browse-seek::-webkit-slider-runnable-track {
  height: 3px;
  border-radius: 99px;
  background: linear-gradient(to right, #f5f5f5 var(--seek, 0%), #3f3f3f var(--seek, 0%));
}

.browse-seek::-webkit-slider-thumb {
  appearance: none;
  width: 16px;
  height: 16px;
  margin-top: -6.5px;
  border: 0;
  border-radius: 50%;
  background: #f5f5f5;
}

.browse-seek::-moz-range-track {
  height: 3px;
  border: 0;
  border-radius: 99px;
  background: #3f3f3f;
}

.browse-seek::-moz-range-progress {
  height: 3px;
  border-radius: 99px;
  background: #f5f5f5;
}

.browse-seek::-moz-range-thumb {
  width: 16px;
  height: 16px;
  border: 0;
  border-radius: 50%;
  background: #f5f5f5;
}

.btn,
.button {
  appearance: none;
  display: inline-block;
  padding: 10px 14px;
  border: 1px solid var(--accent);
  border-radius: 5px;
  background: var(--accent);
  color: #f6f1e8;
  font: inherit;
  font-size: 15px;
  text-decoration: none;
  cursor: pointer;
}

.btn.ghost,
.button.ghost {
  background: transparent;
  color: var(--accent);
}

.btn.note {
  background: #dfe8e2;
  color: var(--accent);
  font-weight: 600;
}

.btn:disabled {
  opacity: 0.55;
  cursor: default;
}

.masthead .brand,
.masthead .nav button {
  display: inline-block;
  margin: 0;
  padding: 0;
  border: 0;
  border-radius: 0;
  background: transparent;
  color: var(--muted);
  font: inherit;
  font-size: 15px;
  font-weight: 400;
  box-shadow: none;
}

.masthead .brand {
  color: var(--ink);
}

.masthead .nav button.on {
  color: var(--ink);
  font-weight: 600;
  box-shadow: inset 0 -2px 0 var(--ink);
}

.progress {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 22px;
  color: var(--muted);
  font-size: 13px;
}

.bar {
  flex: 1;
  height: 4px;
  overflow: hidden;
  border-radius: 999px;
  background: var(--line);
}

.bar > span {
  display: block;
  height: 100%;
  background: var(--accent);
}

.prompt {
  min-height: 120px;
  margin-bottom: 22px;
}

.word {
  margin: 0 0 8px;
  font-family: "Iowan Old Style", "Palatino Linotype", Palatino, Georgia, serif;
  font-size: clamp(32px, 6vw, 44px);
  font-weight: 560;
  letter-spacing: -0.03em;
  line-height: 1.15;
}

.exam-tag {
  margin: -2px 0 10px;
  color: #b8aea3;
  font-size: 12px;
  font-weight: 400;
  letter-spacing: 0.04em;
  line-height: 1.3;
}

.ipa,
.meaning,
.cloze {
  margin: 0;
  color: var(--muted);
  font-size: 18px;
  line-height: 1.55;
}

.ipa,
.explain-word .ipa {
  font-family: "Lucida Grande", Menlo, "PingFang SC", sans-serif;
}

.meaning,
.cloze {
  color: var(--ink);
}

.choices {
  display: grid;
  gap: 10px;
  margin: 0 0 20px;
}

.choice {
  display: flex;
  gap: 12px;
  align-items: flex-start;
  width: 100%;
  padding: 14px 16px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--card);
  color: var(--ink);
  text-align: left;
}

.choice .num {
  flex: 0 0 1.2em;
  color: var(--muted);
  font-size: 13px;
}

.choice .text {
  flex: 1;
  line-height: 1.45;
}

.choice:hover:not(:disabled) {
  border-color: var(--accent);
}

.choice.correct {
  border-color: var(--correct);
  background: #e7efe8;
}

.choice.wrong {
  border-color: var(--wrong);
  background: #f6e8e6;
}

.feedback {
  min-height: 1.5em;
  margin: 0 0 16px;
  color: var(--muted);
  font-size: 14px;
}

.feedback.ok {
  color: var(--correct);
}

.feedback.bad {
  color: var(--wrong);
}

.reveal {
  margin: 0 0 16px;
  padding: 12px 0 0;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 14px;
  line-height: 1.55;
}

.explain {
  margin: 0 0 18px;
  padding: 14px 0 0;
  border-top: 1px solid var(--line);
}

.explain-word {
  margin: 0 0 8px;
  font-family: "Iowan Old Style", "Palatino Linotype", Palatino, Georgia, serif;
  font-size: 22px;
  font-weight: 560;
}

.explain-word .ipa {
  margin-left: 6px;
  font-family: inherit;
  font-size: 15px;
  font-weight: 400;
}

.explain-meaning,
.explain-en,
.explain-zh {
  margin: 0 0 8px;
  line-height: 1.55;
}

.explain-meaning,
.explain-zh {
  color: var(--muted);
  font-size: 14px;
}

.explain-en {
  font-size: 16px;
}

.explain-phrases {
  display: grid;
  gap: 8px;
  margin: 12px 0 0;
  padding: 0;
  list-style: none;
}

.explain-phrases li {
  display: grid;
  gap: 2px;
}

.explain-phrases .en {
  font-size: 15px;
}

.explain-family {
  margin: 10px 0 0;
  color: var(--muted);
  font-size: 13px;
}

.explain-phrases .zh {
  color: var(--muted);
  font-size: 13px;
}

.score {
  margin: 0 0 8px;
  font-size: 28px;
  font-weight: 560;
}

.book-list {
  display: grid;
  gap: 0;
  margin: 28px 0 0;
  padding: 0;
  list-style: none;
}

.book-item {
  padding: 12px 0;
  border-bottom: 1px solid var(--line);
}

.book-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.book-head {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 2px;
  flex: 1;
  min-width: 0;
  padding: 0;
  border: 0;
  border-radius: 0;
  background: transparent;
  color: inherit;
  font: inherit;
  text-align: left;
}

.book-head strong {
  font-size: 18px;
}

.hard-filter {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 4px 22px;
  margin: 4px 0 22px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--line);
}

.hard-pick {
  appearance: none;
  padding: 4px 0 7px;
  border: 0;
  background: none;
  color: #b4aca2;
  font: inherit;
  font-size: 15px;
  cursor: pointer;
  box-shadow: inset 0 -2px 0 transparent;
}

.hard-pick:active {
  transform: translateY(1px);
}

.hard-pick.on {
  font-weight: 600;
}

.hard-pick.lv3.on {
  color: var(--nail-3);
  box-shadow: inset 0 -2px 0 var(--nail-3);
}

.hard-pick.lv2.on {
  color: var(--nail-2);
  box-shadow: inset 0 -2px 0 var(--nail-2);
}

.hard-pick.lv1.on {
  color: var(--nail-1);
  box-shadow: inset 0 -2px 0 var(--nail-1);
}

.hard-pick-count {
  font-weight: 400;
  opacity: 0.55;
}

.hard-pick.on .hard-pick-count {
  opacity: 0.72;
}

.nail-set {
  display: inline-flex;
  align-items: center;
  gap: 2px;
  flex-shrink: 0;
}

.nail {
  appearance: none;
  width: 22px;
  height: 22px;
  padding: 0;
  border: 0;
  background: transparent;
  cursor: pointer;
}

.nail::after {
  content: "";
  display: block;
  width: 8px;
  height: 8px;
  margin: 0 auto;
  border-radius: 50%;
  box-shadow: inset 0 0 0 1.5px var(--line);
  background: transparent;
}

.nail-set.tone-1 .nail.on::after {
  background: var(--nail-1);
  box-shadow: none;
}

.nail-set.tone-2 .nail.on::after {
  background: var(--nail-2);
  box-shadow: none;
}

.nail-set.tone-3 .nail.on::after {
  background: var(--nail-3);
  box-shadow: none;
}

.nail-set:hover .nail.on::after {
  background: transparent;
  box-shadow: inset 0 0 0 1.5px var(--line);
}

.nail-set:hover:has(.nail.lv1:hover) .nail.lv1:hover::after,
.nail-set:hover:has(.nail.lv1:hover) .nail.lv1:has(~ .nail:hover)::after {
  background: var(--nail-1);
  box-shadow: none;
}

.nail-set:hover:has(.nail.lv2:hover) .nail.lv1:hover::after,
.nail-set:hover:has(.nail.lv2:hover) .nail.lv1:has(~ .nail:hover)::after,
.nail-set:hover:has(.nail.lv2:hover) .nail.lv2:hover::after,
.nail-set:hover:has(.nail.lv2:hover) .nail.lv2:has(~ .nail:hover)::after {
  background: var(--nail-2);
  box-shadow: none;
}

.nail-set:hover:has(.nail.lv3:hover) .nail:hover::after,
.nail-set:hover:has(.nail.lv3:hover) .nail:has(~ .nail:hover)::after {
  background: var(--nail-3);
  box-shadow: none;
}

.nail-label {
  margin-left: 6px;
  color: var(--muted);
  font-size: 12px;
  min-width: 2em;
}

.nail-set.tone-1 .nail-label {
  color: var(--nail-1);
}

.nail-set.tone-2 .nail-label {
  color: var(--nail-2);
}

.nail-set.tone-3 .nail-label {
  color: var(--nail-3);
}

.nail-after {
  margin: 12px 0 2px;
}

.nail-dots {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  height: 10px;
}

.nail-dots i {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--accent);
}

.nail-dots.n2 i:nth-child(n + 3),
.nail-dots.n1 i:nth-child(n + 2),
.nail-dots.n0 i {
  background: transparent;
  box-shadow: inset 0 0 0 1.5px var(--line);
}

.book-item .explain {
  margin-top: 10px;
}

.book-forget {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 16px;
  margin: 8px 0 0;
}

.forget {
  appearance: none;
  padding: 0;
  border: 0;
  background: none;
  color: #b4aca2;
  font: inherit;
  font-size: 13px;
  cursor: pointer;
}

.forget:hover {
  color: var(--muted);
}

.wrong-list {
  display: grid;
  gap: 12px;
  margin: 20px 0 28px;
  padding: 0;
  list-style: none;
}

.wrong-list li {
  padding: 12px 0;
  border-bottom: 1px solid var(--line);
}

.wrong-list strong {
  display: block;
  margin-bottom: 4px;
  font-size: 18px;
}

.error {
  color: var(--wrong);
}

code {
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: 0.92em;
}

@media (max-width: 640px) {
  .page {
    width: calc(100% - 28px);
  }

  .word {
    font-size: 30px;
  }

  .nail-label {
    display: none;
  }
}