:root {
  --bg: #f7f8fa;
  --surface: #ffffff;
  --surface-2: #f0f3f6;
  --ink: #121417;
  --muted: #6d737c;
  --faint: #9ba3ad;
  --line: #dfe4ea;
  --line-strong: #c9d1db;
  --red: #d94845;
  --red-soft: #fff0ef;
  --cyan: #047d8d;
  --cyan-soft: #e7f7f9;
  --green: #2f7d52;
  --amber: #a76614;
  --shadow: 0 18px 45px rgba(21, 28, 38, 0.08);
  color-scheme: light;
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  background: var(--bg);
  color: var(--ink);
}

button,
input {
  font: inherit;
}

.app-shell {
  display: grid;
  grid-template-columns: minmax(280px, 340px) minmax(0, 1fr);
  min-height: 100vh;
}

.sidebar {
  display: flex;
  flex-direction: column;
  gap: 18px;
  min-height: 100vh;
  padding: 22px;
  border-right: 1px solid var(--line);
  background: #fbfcfd;
}

.topbar h2,
.panel-head h3 {
  margin: 0;
  letter-spacing: 0;
}

.search {
  display: grid;
  grid-template-columns: 20px 1fr;
  align-items: center;
  gap: 10px;
  min-height: 42px;
  padding: 0 12px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--surface);
}

.search input {
  width: 100%;
  border: 0;
  outline: 0;
  background: transparent;
  color: var(--ink);
  font-size: 14px;
}

.icon svg,
.icon-button svg {
  width: 18px;
  height: 18px;
  fill: none;
  stroke: currentColor;
  stroke-width: 2;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.icon {
  color: var(--faint);
  display: grid;
}

.filter-block {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.filter-title {
  color: var(--muted);
  font-size: 12px;
  font-weight: 700;
}

.segmented {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

.segment {
  min-height: 30px;
  padding: 0 10px;
  border: 1px solid var(--line);
  border-radius: 7px;
  background: var(--surface);
  color: var(--muted);
  cursor: pointer;
  font-size: 12px;
  font-weight: 700;
}

.segment.active {
  border-color: rgba(4, 125, 141, 0.35);
  background: var(--cyan-soft);
  color: var(--cyan);
}

.note-list {
  display: flex;
  flex-direction: column;
  gap: 8px;
  overflow: auto;
  padding-right: 4px;
}

.note-item {
  width: 100%;
  min-height: 68px;
  padding: 11px 12px;
  border: 1px solid transparent;
  border-radius: 8px;
  background: transparent;
  text-align: left;
  cursor: pointer;
}

.note-item:hover {
  background: var(--surface);
}

.note-item.active {
  border-color: var(--line-strong);
  background: var(--surface);
  box-shadow: 0 8px 22px rgba(21, 28, 38, 0.06);
}

.note-item strong {
  display: block;
  color: var(--ink);
  font-size: 14px;
  line-height: 1.25;
}

.note-item span {
  display: block;
  margin-top: 5px;
  color: var(--muted);
  font-size: 12px;
}

.reader {
  min-width: 0;
  padding: 24px;
}

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

.meta-line {
  margin-bottom: 6px;
  color: var(--muted);
  font-size: 12px;
  font-weight: 700;
}

.topbar h2 {
  font-size: clamp(24px, 3vw, 38px);
  line-height: 1.08;
}

.stats-row {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 10px;
  margin-bottom: 18px;
}

.stat-card {
  min-height: 78px;
  padding: 14px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--surface);
}

.stat-card span {
  display: block;
  font-size: 26px;
  font-weight: 850;
  line-height: 1;
}

.stat-card strong {
  display: block;
  margin-top: 8px;
  color: var(--muted);
  font-size: 12px;
}

.content-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(300px, 360px);
  gap: 18px;
  align-items: start;
}

.markdown-panel,
.queue-panel {
  min-width: 0;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--surface);
  box-shadow: var(--shadow);
}

.panel-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 14px;
  min-height: 56px;
  padding: 14px 16px;
  border-bottom: 1px solid var(--line);
}

.panel-head h3 {
  font-size: 15px;
}

.section-tabs {
  display: flex;
  gap: 6px;
  overflow-x: auto;
}

.section-tab {
  max-width: 150px;
  min-height: 28px;
  padding: 0 9px;
  border: 1px solid var(--line);
  border-radius: 7px;
  background: var(--surface);
  color: var(--muted);
  cursor: pointer;
  font-size: 12px;
  font-weight: 700;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.section-tab:hover {
  border-color: var(--line-strong);
  color: var(--ink);
}

.markdown-view {
  padding: 22px 28px 34px;
}

.markdown-view h1,
.markdown-view h2,
.markdown-view h3,
.markdown-view h4 {
  margin: 24px 0 10px;
  line-height: 1.18;
  letter-spacing: 0;
}

.markdown-view h1:first-child,
.markdown-view h2:first-child {
  margin-top: 0;
}

.markdown-view h1 {
  font-size: 28px;
}

.markdown-view h2 {
  font-size: 21px;
}

.markdown-view h3 {
  font-size: 17px;
}

.markdown-view p,
.markdown-view li {
  color: #262b31;
  font-size: 14px;
  line-height: 1.72;
}

.markdown-view ul {
  padding-left: 22px;
}

code {
  padding: 2px 5px;
  border-radius: 5px;
  background: var(--surface-2);
  color: #b92f2b;
  font-family: "SFMono-Regular", Consolas, "Liberation Mono", monospace;
  font-size: 0.92em;
}

.markdown-view table {
  width: 100%;
  margin: 16px 0;
  border-collapse: collapse;
  font-size: 13px;
}

.markdown-view th,
.markdown-view td {
  padding: 9px 10px;
  border: 1px solid var(--line);
  text-align: left;
  vertical-align: top;
}

.markdown-view th {
  background: var(--surface-2);
}

.queue-panel {
  align-self: start;
}

.icon-button {
  display: grid;
  place-items: center;
  width: 34px;
  height: 34px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--surface);
  color: var(--muted);
  cursor: pointer;
}

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

.queue-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
  padding: 14px;
}

.queue-item {
  padding: 12px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #fcfdfe;
  cursor: pointer;
}

.queue-item:hover {
  border-color: var(--line-strong);
  background: var(--surface);
}

.queue-item .badge {
  display: inline-flex;
  align-items: center;
  min-height: 22px;
  padding: 0 7px;
  border-radius: 6px;
  font-size: 11px;
  font-weight: 850;
}

.badge.practice {
  background: var(--cyan-soft);
  color: var(--cyan);
}

.badge.verify {
  background: var(--red-soft);
  color: var(--red);
}

.badge.unverified {
  background: #fff5dc;
  color: var(--amber);
}

.badge.todo {
  background: #eaf6ef;
  color: var(--green);
}

.queue-item p {
  margin: 10px 0 8px;
  font-size: 13px;
  line-height: 1.55;
}

.queue-item footer {
  color: var(--muted);
  font-size: 12px;
}

.empty {
  padding: 22px;
  color: var(--muted);
  text-align: center;
  font-size: 13px;
}

mark {
  padding: 0 2px;
  border-radius: 3px;
  background: #fff1a8;
}

@media (max-width: 980px) {
  .app-shell {
    grid-template-columns: 1fr;
  }

  .sidebar {
    min-height: auto;
    border-right: 0;
    border-bottom: 1px solid var(--line);
  }

  .note-list {
    max-height: 260px;
  }

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

  .queue-panel {
    position: static;
  }
}

@media (max-width: 640px) {
  .app-shell,
  .reader,
  .sidebar,
  .topbar-main,
  .markdown-panel,
  .queue-panel,
  .stat-card {
    min-width: 0;
    width: 100%;
  }

  .reader,
  .sidebar {
    padding: 16px;
  }

  .segmented {
    flex-wrap: nowrap;
    overflow-x: auto;
    padding-bottom: 2px;
  }

  .segment {
    flex: 0 0 auto;
  }

  .topbar {
    flex-direction: column;
  }

  .topbar h2,
  .markdown-view h1,
  .markdown-view h2,
  .note-item strong {
    overflow-wrap: anywhere;
  }

  .markdown-view {
    padding: 18px;
  }
}