:root {
  color-scheme: light;
  --bg: #d8e2c6;
  --surface: #eee6d2;
  --surface-2: #dfe8c8;
  --ink: #1f251f;
  --muted: #687064;
  --line: #d4c8b6;
  --accent: #2f6f68;
  --accent-ink: #f2fffb;
  --translation: #183f48;
  --mark: #fff7c2;
  --shadow: 0 18px 55px rgba(45, 37, 25, 0.18);
  --page-bg: #dfe8c8;
  --paper-top: #e0e8ce;
  --paper-mid: #d8e2c6;
  --paper-bottom: #d1dcbc;
  --paper-dark-top: #121713;
  --paper-dark-bottom: #111512;
}

body.dark {
  color-scheme: dark;
  --bg: #111512;
  --surface: #1d241f;
  --surface-2: #273027;
  --ink: #e4eadf;
  --muted: #abb5a8;
  --line: #374236;
  --accent: #82cabf;
  --accent-ink: #10201c;
  --translation: #8fa9b0;
  --mark: rgba(130, 202, 191, 0.22);
  --shadow: 0 18px 55px rgba(0, 0, 0, 0.38);
  --page-bg: #111512;
}

* {
  box-sizing: border-box;
}

[hidden] {
  display: none !important;
}

body {
  margin: 0;
  min-height: 100vh;
  padding-bottom: 132px;
  background: linear-gradient(180deg, var(--paper-top) 0%, var(--paper-mid) 42%, var(--paper-bottom) 100%);
  color: var(--ink);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
}

body.dark {
  background: linear-gradient(180deg, var(--paper-dark-top) 0%, var(--paper-dark-bottom) 100%);
}

button {
  font: inherit;
  cursor: pointer;
}

.topbar {
  display: none;
  position: fixed;
  left: clamp(8px, 3vw, 24px);
  right: clamp(8px, 3vw, 24px);
  top: 58px;
  z-index: 34;
  align-items: flex-start;
  flex-direction: column;
  gap: 12px;
  max-width: 760px;
  margin: 0 auto;
  padding: 7px clamp(8px, 2vw, 16px);
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  border: 1px solid var(--line);
  border-radius: 10px;
  box-shadow: var(--shadow);
  backdrop-filter: blur(16px);
}

body.menu-open .topbar {
  display: flex;
}

.menu-fab {
  display: block;
  position: fixed;
  right: 10px;
  top: 10px;
  z-index: 35;
  width: 42px;
  height: 42px;
  color: var(--ink);
  background: color-mix(in srgb, var(--surface) 92%, transparent);
  border: 1px solid var(--line);
  border-radius: 999px;
  box-shadow: var(--shadow);
  backdrop-filter: blur(16px);
}

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

h1,
h2 {
  margin: 0;
  letter-spacing: 0;
}

h1 {
  font-size: clamp(20px, 2.4vw, 26px);
}

h2 {
  font-size: 20px;
  line-height: 1.35;
}

.top-actions,
.panel-actions {
  display: flex;
  align-items: center;
  gap: 6px;
  flex-wrap: wrap;
}

.top-actions {
  width: 100%;
}

.color-picker {
  width: 32px;
  height: 30px;
  padding: 2px;
  background: var(--surface-2);
  border: 1px solid var(--line);
  border-radius: 8px;
}

.range-control {
  display: grid;
  grid-template-columns: auto minmax(92px, 1fr) 26px;
  align-items: center;
  gap: 6px;
  min-height: 30px;
  padding: 4px 7px;
  color: var(--ink);
  background: var(--surface-2);
  border: 1px solid var(--line);
  border-radius: 8px;
  font-size: 13px;
}

.range-control input {
  width: 100%;
  accent-color: var(--accent);
}

.range-control output {
  color: var(--muted);
  text-align: right;
  font-variant-numeric: tabular-nums;
}

body.highlight-mode #highlightToggle {
  color: var(--accent-ink);
  background: var(--accent);
  border-color: var(--accent);
}

body.study-mode #modeToggle {
  color: var(--accent-ink);
  background: var(--accent);
  border-color: var(--accent);
}

.pdf-shell {
  width: 100%;
  margin: 0 auto;
  padding: 0;
}

.pdf-stage {
  display: flex;
  justify-content: center;
  padding-bottom: 132px;
}

.pdf-page {
  position: relative;
  width: min(100vw, 760px);
  aspect-ratio: 612 / 792;
  background: var(--page-bg);
  border: 0;
  box-shadow: none;
  overflow: visible;
}

.pdf-page.original-scroll {
  display: block;
  width: min(100%, 760px);
  aspect-ratio: auto;
  background: transparent;
}

.original-page {
  position: relative;
  width: 100%;
  margin: 0 auto;
  background: var(--page-bg);
  overflow: visible;
}

body.dark .original-page {
  background: var(--page-bg);
}

.original-slice-page {
  padding: 8px 0 22px;
  min-height: auto;
}

.original-row {
  break-inside: avoid;
  margin: 0 0 2px;
}

.original-image-strip {
  position: relative;
  width: 100%;
  min-height: 18px;
  background-image: var(--page-image);
  background-size: 100% auto;
  background-position: 0 var(--bg-y);
  background-repeat: no-repeat;
  mix-blend-mode: multiply;
}

body.dark .original-image-strip {
  filter: invert(0.86) hue-rotate(180deg) brightness(0.82) contrast(0.92) saturate(0.72);
  mix-blend-mode: normal;
}

.original-strip-tools {
  position: absolute;
  z-index: 8;
  display: inline-flex;
  gap: 2px;
  transform: translateY(-50%);
}

.original-line-tool {
  position: static;
  transform: none;
}

.original-word-hotspot {
  z-index: 7;
}

.original-row-translations {
  display: grid;
  gap: 1px;
  padding: 1px 10px 2px;
  background: var(--page-bg);
}

.original-translation-block {
  width: var(--item-width, 100%);
  margin-left: var(--indent, 0);
  color: var(--translation);
  font-family: "PingFang SC", "Hiragino Sans GB", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  font-size: clamp(9px, 2.2vw, 12px);
  font-weight: 400;
  line-height: 1.16;
  overflow-wrap: break-word;
}

.merged-original-unit {
  padding-bottom: 2px;
}

.cross-page-original-unit {
  border-bottom: 1px dashed color-mix(in srgb, var(--accent) 35%, transparent);
}

.pdf-page img,
.original-page img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: contain;
  user-select: none;
  mix-blend-mode: multiply;
}

body.dark .pdf-page img {
  filter: invert(0.86) hue-rotate(180deg) brightness(0.82) contrast(0.92) saturate(0.72);
  mix-blend-mode: normal;
}

.line-layer,
.word-layer,
.highlight-layer {
  position: absolute;
  inset: 0;
}

.highlight-layer {
  z-index: 2;
  pointer-events: none;
}

.custom-highlight {
  position: absolute;
  border-radius: 3px;
  mix-blend-mode: multiply;
  opacity: 0.56;
}

body.dark .custom-highlight {
  mix-blend-mode: screen;
  opacity: 0.42;
}

.line-tools {
  position: absolute;
  z-index: 5;
  display: flex;
  gap: 2px;
  transform: translateY(-50%);
}

.line-tool {
  width: 18px;
  height: 16px;
  padding: 0;
  color: var(--accent);
  background: color-mix(in srgb, var(--surface) 92%, transparent);
  border: 1px solid color-mix(in srgb, var(--accent) 38%, var(--line));
  border-radius: 5px;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
  font-size: 9px;
  font-weight: 700;
}

.word-hotspot {
  position: absolute;
  z-index: 6;
  padding: 0;
  background: transparent;
  border: 0;
  border-radius: 3px;
}

.word-hotspot:hover {
  background: color-mix(in srgb, var(--accent) 14%, transparent);
  outline: 1px solid color-mix(in srgb, var(--accent) 42%, transparent);
  mix-blend-mode: multiply;
}

body.dark .word-hotspot:hover {
  mix-blend-mode: screen;
}

.study-page {
  width: min(100%, 820px);
  margin: 0 auto;
  padding: 8px 12px 180px;
  scroll-padding-top: 68px;
  background: var(--page-bg);
}

.study-page-divider {
  display: flex;
  align-items: center;
  gap: 10px;
  margin: 18px 0 10px;
  color: var(--muted);
  font-size: 13px;
  font-weight: 700;
  scroll-margin-top: 78px;
}

.study-page-divider::before,
.study-page-divider::after {
  content: "";
  flex: 1;
  border-top: 1px dashed color-mix(in srgb, var(--muted) 58%, transparent);
}

.study-page-divider:first-child {
  margin-top: 4px;
}

.study-item {
  padding: 9px 0 13px;
  border-bottom: 1px solid color-mix(in srgb, var(--line) 60%, transparent);
}

.merged-study-item {
  padding-top: 7px;
}

.cross-page-study-item {
  border-bottom-color: color-mix(in srgb, var(--accent) 30%, var(--line));
}

.study-en {
  display: flex;
  align-items: flex-start;
  gap: 7px;
  color: #1d251f;
  font-family: "Courier New", Menlo, Consolas, monospace;
  font-size: clamp(16px, 4.15vw, 20px);
  font-weight: 700;
  line-height: 1.36;
  overflow-wrap: anywhere;
}

body.dark .study-en {
  color: var(--ink);
}

.study-en-text {
  min-width: 0;
  flex: 1;
}

.study-zh {
  margin: 7px 0 0;
  padding-left: 4px;
  color: var(--translation);
  font-family: "PingFang SC", "Hiragino Sans GB", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  font-size: clamp(12px, 3.12vw, 15px);
  font-weight: 400;
  line-height: 1.34;
}

.study-speak {
  flex: 0 0 auto;
  min-width: 30px;
  min-height: 28px;
  padding: 0 7px;
  color: var(--accent);
  background: var(--surface-2);
  border: 1px solid color-mix(in srgb, var(--accent) 45%, var(--line));
  border-radius: 8px;
}

.study-word {
  display: inline;
  padding: 0 1px;
  color: inherit;
  background: transparent;
  border: 0;
  border-radius: 4px;
  font: inherit;
  line-height: inherit;
  vertical-align: baseline;
}

.study-word:hover {
  color: var(--accent);
  background: color-mix(in srgb, var(--accent) 12%, transparent);
}

.study-letter-original {
  background: rgba(238, 218, 42, 0.58);
  border-radius: 2px;
  box-decoration-break: clone;
  -webkit-box-decoration-break: clone;
}

body.dark .study-letter-original {
  background: rgba(214, 191, 54, 0.28);
}

.study-word.custom-highlighted {
  box-decoration-break: clone;
  -webkit-box-decoration-break: clone;
}

.translation-bubble {
  position: absolute;
  z-index: 3;
  padding: 3px 6px;
  color: var(--translation);
  background: transparent;
  border: 0;
  border-radius: 0;
  font-size: clamp(8px, 1.52vw, 10px);
  line-height: 1.16;
  overflow: visible;
  font-weight: 400;
  font-family: "PingFang SC", "Hiragino Sans GB", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  white-space: normal;
  overflow-wrap: break-word;
  min-height: max-content;
}

.translation-bubble.merged-translation {
  padding-top: 5px;
  line-height: 1.18;
}

body:not(.show-all-translations) .translation-bubble {
  display: none;
}

body:not(.show-all-translations) .original-row-translations {
  display: none;
}

.icon-button,
.tool-button,
.primary-button {
  min-height: 30px;
  padding: 4px 7px;
  color: var(--ink);
  background: var(--surface-2);
  border: 1px solid var(--line);
  border-radius: 8px;
}

.icon-button {
  width: 32px;
  padding: 0;
}

.primary-button {
  color: var(--accent-ink);
  background: var(--accent);
  border-color: var(--accent);
}

.translation-panel,
.word-panel {
  position: fixed;
  left: 50%;
  right: auto;
  bottom: calc(58px + env(safe-area-inset-bottom, 0px));
  z-index: 40;
  width: min(520px, calc(100vw - 24px));
  max-height: min(520px, calc(100vh - 112px));
  overflow: auto;
  padding: 16px;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 8px;
  box-shadow: var(--shadow);
  transform: translateX(-50%);
}

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

#lineChinese,
#wordMeaning,
#wordExpansion {
  margin: 0 0 12px;
  color: var(--muted);
  line-height: 1.65;
}

#lineChinese {
  color: var(--translation);
  font-size: 0.8em;
  line-height: 1.36;
  font-weight: 400;
  font-family: "PingFang SC", "Hiragino Sans GB", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

.note-card {
  padding: 10px;
  background: var(--surface-2);
  border: 1px solid var(--line);
  border-radius: 8px;
}

.hintbar {
  position: fixed;
  right: max(8px, env(safe-area-inset-right, 0px));
  bottom: max(8px, env(safe-area-inset-bottom, 0px));
  z-index: 30;
  display: grid;
  grid-template-columns: 62px;
  align-items: end;
  width: max-content;
  max-width: calc(100vw - 12px);
  padding: 4px;
  color: var(--muted);
  background: color-mix(in srgb, var(--surface) 90%, transparent);
  border: 1px solid var(--line);
  border-radius: 8px;
  box-shadow: none;
  backdrop-filter: blur(16px);
  font-size: 11px;
}

.page-button,
.page-picker select {
  width: 100%;
  min-height: 28px;
  color: var(--ink);
  background: var(--surface-2);
  border: 1px solid var(--line);
  border-radius: 8px;
  font: inherit;
}

.page-button:disabled {
  opacity: 0.48;
  cursor: not-allowed;
}

.page-picker {
  display: grid;
  gap: 2px;
}

.page-picker span {
  display: none;
}

.vocab-page {
  width: min(900px, 100%);
  margin: 0 auto;
  padding: 14px clamp(10px, 3vw, 28px) 72px;
}

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

.vocab-list {
  display: grid;
  gap: 8px;
}

.vocab-row {
  display: grid;
  grid-template-columns: minmax(92px, 0.8fr) minmax(0, 1.6fr) 54px;
  align-items: center;
  gap: 8px;
  padding: 10px;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 8px;
  cursor: pointer;
}

.vocab-row:hover,
.vocab-row:focus {
  border-color: color-mix(in srgb, var(--accent) 50%, var(--line));
  background: color-mix(in srgb, var(--accent) 8%, var(--surface));
  outline: none;
}

.vocab-word {
  color: var(--ink);
  font-weight: 750;
  font-size: 17px;
}

.vocab-meaning {
  color: var(--translation);
  line-height: 1.45;
  font-weight: 400;
  font-family: "PingFang SC", "Hiragino Sans GB", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

.vocab-row button {
  min-height: 30px;
}

.toast {
  position: fixed;
  left: 50%;
  bottom: 76px;
  z-index: 60;
  transform: translateX(-50%);
  padding: 9px 12px;
  color: var(--surface);
  background: var(--ink);
  border-radius: 8px;
}

@media (max-width: 760px) {
  .topbar {
    left: 8px;
    right: 8px;
    max-width: none;
  }

  .tool-button {
    flex: 1 1 auto;
  }

  .line-tool {
    width: 18px;
    height: 16px;
    font-size: 9px;
  }

  .pdf-page:not(.original-scroll) {
    display: none;
  }

  body.original-mode .pdf-page {
    display: block;
  }

  body.original-mode .study-page {
    display: none !important;
  }

  body:not(.original-mode) .study-page {
    display: block;
  }

  .translation-bubble {
    max-width: 58%;
  }

  .hintbar {
    grid-template-columns: 58px;
  }
}

@media (max-width: 430px) {
  .topbar {
    align-items: flex-start;
    flex-direction: column;
  }

  .top-actions {
    width: 100%;
  }

  .tool-button {
    flex: 1 1 auto;
  }

  .vocab-row {
    grid-template-columns: 1fr 1fr;
  }

  .vocab-meaning {
    grid-column: 1 / -1;
  }
}