:root {
  color-scheme: light;
  --ink: #111a33;
  --muted: #667085;
  --subtle: #8a98ad;
  --line: #dce7f7;
  --soft-line: #edf3fb;
  --paper: #f5f9ff;
  --panel: #ffffff;
  --blue: #0066ff;
  --blue-dark: #004dd6;
  --blue-soft: #eaf3ff;
  --cyan: #2cc8ff;
  --orange: #f08a4b;
  --gold: #f4b83f;
  --violet: #6d63ff;
  font-family:
    Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI",
    "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  background:
    radial-gradient(circle at 18% 14%, rgba(0, 102, 255, 0.11), transparent 32%),
    linear-gradient(180deg, #f7fbff 0%, #eef6ff 48%, #f8fbff 100%);
  color: var(--ink);
}

button,
input,
textarea {
  font: inherit;
}

button {
  min-height: 44px;
  border: 0;
  border-radius: 8px;
  background: var(--blue);
  color: #fff;
  cursor: pointer;
  font-weight: 800;
  transition:
    transform 160ms ease,
    box-shadow 160ms ease,
    background 160ms ease;
}

button:hover {
  background: var(--blue-dark);
  box-shadow: 0 14px 30px rgba(0, 102, 255, 0.18);
  transform: translateY(-1px);
}

button:disabled {
  cursor: not-allowed;
  opacity: 0.62;
  transform: none;
}

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

h1 {
  margin-bottom: 18px;
  color: var(--ink);
  font-size: clamp(44px, 7.5vw, 86px);
  line-height: 1.02;
  letter-spacing: 0;
}

h2 {
  margin-bottom: 12px;
  font-size: clamp(26px, 3vw, 38px);
  line-height: 1.18;
  letter-spacing: 0;
}

h3 {
  margin-bottom: 8px;
  font-size: 20px;
  line-height: 1.28;
}

.screen {
  width: min(1360px, calc(100vw - 40px));
  margin: 0 auto;
  padding: 22px 0 56px;
}

.topbar {
  position: sticky;
  top: 12px;
  z-index: 5;
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  gap: 20px;
  min-height: 74px;
  border: 1px solid rgba(210, 224, 244, 0.92);
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.92);
  padding: 12px 16px;
  box-shadow: 0 20px 50px rgba(17, 49, 96, 0.08);
  backdrop-filter: blur(16px);
}

.brand-button,
.nav-links button {
  border: 0;
  background: transparent;
  color: var(--ink);
}

.brand-button {
  display: inline-flex;
  align-items: center;
  justify-self: start;
  gap: 18px;
  min-height: 0;
  padding: 0;
  font-weight: 700;
}

.brand-button:hover,
.nav-links button:hover {
  background: transparent;
  box-shadow: none;
  color: var(--blue);
  transform: none;
}

.brand-logo {
  display: block;
  width: clamp(112px, 12vw, 160px);
  height: auto;
}

.brand-button span {
  color: var(--muted);
  font-size: 14px;
}

.nav-links {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 18px;
}

.nav-links button {
  position: relative;
  min-height: 42px;
  border-radius: 8px;
  padding: 8px 10px;
  font-size: 16px;
  font-weight: 800;
}

.nav-links button.active {
  color: var(--blue);
}

.nav-links button.active::after {
  position: absolute;
  right: 10px;
  bottom: 2px;
  left: 10px;
  height: 3px;
  border-radius: 999px;
  background: var(--blue);
  content: "";
}

.nav-cta {
  justify-self: end;
  padding: 0 18px;
}

.eyebrow {
  margin: 0 0 10px;
  color: var(--blue);
  font-size: 14px;
  font-weight: 900;
}

.lead {
  max-width: 760px;
  color: var(--muted);
  font-size: clamp(18px, 2vw, 24px);
  line-height: 1.62;
}

.hero-shell {
  position: relative;
  overflow: hidden;
  margin-top: 18px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background:
    linear-gradient(90deg, rgba(255, 255, 255, 0.98) 0%, rgba(247, 251, 255, 0.92) 58%, rgba(231, 243, 255, 0.86) 100%),
    radial-gradient(circle at 70% 70%, rgba(0, 102, 255, 0.12), transparent 34%);
  box-shadow: 0 22px 60px rgba(20, 67, 128, 0.1);
}

.landing-hero {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(390px, 470px);
  gap: 34px;
  align-items: center;
  padding: clamp(42px, 7vw, 88px);
}

.hero-copy {
  position: relative;
  z-index: 1;
}

.hero-actions,
.actions {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  margin-top: 28px;
}

.hero-actions button,
.actions button {
  padding: 0 22px;
  font-size: 16px;
}

.ghost-button {
  border: 1px solid #b9d3ff;
  background: #fff;
  color: var(--blue);
}

.ghost-button:hover {
  background: var(--blue-soft);
  color: var(--blue-dark);
}

.hero-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  margin-top: 42px;
  color: var(--muted);
  font-weight: 700;
}

.hero-meta span {
  display: inline-flex;
  align-items: center;
  gap: 8px;
}

.hero-meta span::before {
  width: 18px;
  height: 18px;
  border: 2px solid var(--blue);
  border-radius: 6px;
  background: #fff;
  content: "";
}

.hero-book-preview {
  display: grid;
  grid-template-columns: minmax(220px, 1fr) 172px;
  gap: 22px;
  align-items: center;
}

.stat-stack {
  display: grid;
  gap: 14px;
}

.stat-stack span {
  min-height: 78px;
  display: flex;
  align-items: center;
  gap: 10px;
  border: 1px solid var(--soft-line);
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.92);
  padding: 14px 16px;
  color: var(--ink);
  font-size: 17px;
  font-weight: 800;
  box-shadow: 0 16px 34px rgba(20, 67, 128, 0.08);
}

.stat-stack strong {
  color: var(--blue);
  font-size: 30px;
}

.section-block {
  margin-top: 28px;
}

.section-heading {
  margin-bottom: 18px;
}

.section-heading.row {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  gap: 18px;
}

.section-heading h2 {
  margin-bottom: 0;
}

.compact-heading {
  align-items: center;
}

.soft-note {
  color: var(--subtle);
  font-size: 14px;
  font-weight: 700;
}

.feature-grid,
.flow-grid,
.shelf-grid {
  display: grid;
  gap: 18px;
}

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

.feature-grid article,
.flow-grid article,
.start-panel,
.start-flow-card,
.zhihu-fit-card,
.reading-card,
.side-panel,
.preface,
.toc,
.authors-panel,
.route-timeline,
.empty-state {
  border: 1px solid var(--line);
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.94);
  box-shadow: 0 18px 45px rgba(20, 67, 128, 0.07);
}

.feature-grid article {
  min-height: 180px;
  padding: 26px;
}

.feature-icon {
  display: inline-grid;
  width: 50px;
  height: 50px;
  place-items: center;
  margin-bottom: 24px;
  border-radius: 8px;
  background: var(--blue-soft);
  color: var(--blue);
  font-weight: 900;
}

.feature-grid strong,
.flow-grid strong {
  display: block;
  margin-bottom: 10px;
  font-size: 22px;
}

.feature-grid p,
.flow-grid p,
.reading-card p,
.side-panel p,
.preface p,
.authors-panel p {
  color: var(--muted);
  line-height: 1.7;
}

.flow-grid {
  grid-template-columns: repeat(4, 1fr);
}

.flow-grid article {
  min-height: 178px;
  padding: 22px;
}

.flow-grid span {
  display: inline-grid;
  width: 36px;
  height: 36px;
  place-items: center;
  margin-bottom: 20px;
  border-radius: 999px;
  background: var(--blue);
  color: #fff;
  font-weight: 900;
}

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

.shelf-card {
  display: grid;
  grid-template-columns: 148px minmax(0, 1fr);
  gap: 22px;
  align-items: center;
  min-height: 250px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.96);
  padding: 18px;
  box-shadow: 0 16px 42px rgba(20, 67, 128, 0.08);
  cursor: pointer;
  transition:
    transform 160ms ease,
    border-color 160ms ease,
    box-shadow 160ms ease;
}

.shelf-card:hover {
  border-color: #9bc5ff;
  box-shadow: 0 24px 54px rgba(0, 102, 255, 0.12);
  transform: translateY(-2px);
}

.shelf-copy {
  min-width: 0;
}

.card-kicker {
  display: inline-flex;
  margin-bottom: 8px;
  border-radius: 999px;
  background: var(--blue-soft);
  padding: 5px 9px;
  color: var(--blue);
  font-size: 12px;
  font-weight: 900;
}

.shelf-card h3 {
  margin-bottom: 8px;
}

.shelf-card p {
  margin-bottom: 10px;
  color: var(--muted);
  line-height: 1.55;
}

.mini-cover {
  position: relative;
  overflow: hidden;
  aspect-ratio: 3 / 4;
  width: 100%;
  border: 1px solid rgba(0, 70, 160, 0.24);
  border-radius: 8px;
  background:
    linear-gradient(160deg, rgba(255, 255, 255, 0.95), rgba(230, 241, 255, 0.72)),
    linear-gradient(140deg, #ffffff, #eaf3ff);
  box-shadow:
    inset 8px 0 0 rgba(0, 67, 160, 0.1),
    0 18px 32px rgba(17, 49, 96, 0.14);
  color: var(--ink);
}

.mini-cover.large {
  max-width: 320px;
  min-width: 250px;
  justify-self: center;
}

.cover-brand {
  position: absolute;
  left: 14px;
  bottom: 12px;
  z-index: 2;
  color: var(--blue);
  font-size: 13px;
  font-weight: 900;
}

.cover-title {
  position: absolute;
  top: 20px;
  left: 18px;
  right: 18px;
  z-index: 2;
  color: var(--ink);
  font-size: clamp(18px, 2vw, 32px);
  font-weight: 900;
  line-height: 1.25;
}

.mini-cover:not(.large) .cover-title {
  font-size: 18px;
}

.cover-lines {
  position: absolute;
  right: -20%;
  bottom: 18%;
  width: 120%;
  height: 34%;
  border-top: 4px solid rgba(0, 102, 255, 0.22);
  border-bottom: 4px solid rgba(0, 102, 255, 0.18);
  border-radius: 50%;
  transform: rotate(-10deg);
}

.cover-art {
  position: absolute;
  right: 14px;
  bottom: 42px;
  left: 18px;
  height: 44%;
}

.cover-art span {
  position: absolute;
  border-radius: 999px;
  background: var(--blue);
}

.cover-art span:nth-child(1) {
  width: 46%;
  height: 46%;
  left: 4%;
  bottom: 8%;
  border: 2px solid rgba(255, 255, 255, 0.7);
  background: linear-gradient(160deg, #004fbf, #0a8bff);
}

.cover-art span:nth-child(2) {
  width: 14px;
  height: 14px;
  left: 58%;
  bottom: 52%;
}

.cover-art span:nth-child(3) {
  width: 10px;
  height: 10px;
  left: 76%;
  bottom: 72%;
  background: var(--cyan);
}

.cover-art span:nth-child(4) {
  width: 22px;
  height: 22px;
  left: 68%;
  bottom: 22%;
  background: var(--gold);
}

.cover-cocoon {
  background: linear-gradient(160deg, #ffffff, #e7f5f1);
}

.cover-cocoon .cover-art span:nth-child(1) {
  border-radius: 8px;
  background: linear-gradient(160deg, #0a8b86, #c8f0df);
}

.cover-public {
  background: linear-gradient(160deg, #fff9f5, #ffe8d9);
}

.cover-public .cover-art span {
  background: var(--orange);
}

.cover-writer {
  background: linear-gradient(160deg, #fffdf5, #fff0c8);
}

.cover-writer .cover-art span {
  background: var(--gold);
}

.cover-hot {
  background: linear-gradient(160deg, #fff, #eeeaff);
}

.cover-hot .cover-art span {
  background: var(--violet);
}

.cover-classic {
  background: linear-gradient(160deg, #ffffff, #e2f6ff);
}

.cover-classic .cover-art span {
  background: #008bc7;
}

.avatar-group {
  display: flex;
  align-items: center;
  min-height: 30px;
  margin: 10px 0;
}

.avatar-group span,
.avatar-group em,
.author-item > span {
  display: inline-grid;
  width: 30px;
  height: 30px;
  place-items: center;
  margin-left: calc(var(--i, 0) * -5px);
  border: 2px solid #fff;
  border-radius: 999px;
  background: linear-gradient(160deg, #d8eaff, #fff);
  color: var(--blue);
  font-size: 12px;
  font-style: normal;
  font-weight: 900;
  box-shadow: 0 6px 14px rgba(17, 49, 96, 0.1);
}

.avatar-group span:first-child {
  margin-left: 0;
}

.avatar-group em {
  background: #f1f5fb;
  color: var(--muted);
}

.book-card-footer,
.book-stats,
.detail-stats,
.tag-row {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.book-card-footer span,
.book-stats span {
  border-radius: 999px;
  background: #f3f8ff;
  color: var(--muted);
  padding: 6px 10px;
  font-size: 13px;
  font-weight: 800;
}

.tag-row {
  margin: 16px 0;
}

.tag-row.compact {
  margin: 8px 0;
}

.tag-row span {
  border: 1px solid #b9d3ff;
  border-radius: 999px;
  background: #f2f7ff;
  color: var(--blue);
  padding: 6px 10px;
  font-size: 13px;
  font-weight: 800;
}

.page-heading {
  padding: 54px 0 18px;
}

.page-heading h1,
.compact-hero h1 {
  font-size: clamp(38px, 5.2vw, 64px);
}

.empty-state {
  display: grid;
  grid-template-columns: 260px minmax(0, 1fr);
  gap: 46px;
  align-items: center;
  min-height: 280px;
  padding: 38px 62px;
}

.empty-state .mini-cover {
  max-width: 190px;
}

.empty-state p {
  color: var(--muted);
  font-size: 18px;
  line-height: 1.6;
}

.empty-state button {
  margin-top: 16px;
  padding: 0 22px;
}

.start-hero-card {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(260px, 360px);
  gap: 36px;
  align-items: end;
  margin-top: 46px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background:
    linear-gradient(135deg, rgba(255, 255, 255, 0.96), rgba(241, 248, 255, 0.92)),
    linear-gradient(90deg, rgba(244, 184, 63, 0.1), rgba(0, 102, 255, 0.08));
  padding: clamp(28px, 5vw, 52px);
  box-shadow: 0 22px 60px rgba(20, 67, 128, 0.08);
}

.start-hero-card h1 {
  max-width: 920px;
  font-size: clamp(38px, 5.6vw, 72px);
}

.start-hero-metrics {
  display: grid;
  gap: 12px;
}

.start-hero-metrics span {
  display: grid;
  gap: 2px;
  min-height: 72px;
  border: 1px solid var(--soft-line);
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.82);
  padding: 13px 15px;
  color: var(--muted);
  font-size: 14px;
  font-weight: 850;
  box-shadow: 0 12px 28px rgba(20, 67, 128, 0.06);
}

.start-hero-metrics strong {
  color: var(--ink);
  font-size: 28px;
  line-height: 1;
}

.start-layout {
  display: grid;
  grid-template-columns: minmax(520px, 0.95fr) minmax(340px, 0.62fr);
  gap: 22px;
  align-items: start;
  padding-top: 22px;
}

.start-panel {
  padding: clamp(22px, 3vw, 32px);
}

.start-panel-head {
  max-width: 690px;
  margin-bottom: 22px;
}

.start-panel-head h2,
.start-flow-card h2,
.zhihu-fit-card h2 {
  margin-bottom: 8px;
  font-size: clamp(24px, 2.4vw, 32px);
}

.start-panel-head p,
.zhihu-fit-card p {
  margin-bottom: 0;
  color: var(--muted);
  line-height: 1.7;
}

.start-panel label {
  display: block;
  margin-bottom: 12px;
  font-size: 18px;
  font-weight: 900;
}

.paste-block {
  margin-top: 18px;
}

.paste-block label {
  color: var(--muted);
  font-size: 15px;
}

.start-ai-notes {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 14px;
}

.start-ai-notes span {
  border-radius: 999px;
  background: #fff8e7;
  color: #8a5a00;
  padding: 7px 10px;
  font-size: 13px;
  font-weight: 800;
}

.start-form-actions {
  margin-top: 16px;
}

.input-row {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 12px;
}

input,
textarea {
  width: 100%;
  min-width: 0;
  border: 1px solid #bdd6ff;
  border-radius: 8px;
  background: #fff;
  color: var(--ink);
  padding: 14px 16px;
  outline: 0;
}

textarea {
  min-height: 118px;
  resize: vertical;
  line-height: 1.65;
}

input:focus,
textarea:focus {
  border-color: var(--blue);
  box-shadow: 0 0 0 4px rgba(0, 102, 255, 0.12);
}

.input-row button {
  padding: 0 22px;
}

.hint {
  margin: 12px 0 0;
  color: var(--muted);
}

.hint.good {
  color: var(--blue);
  font-weight: 800;
}

.status-message,
.error-message {
  margin: 12px 0 0;
  border-radius: 8px;
  padding: 10px 12px;
  font-weight: 800;
}

.status-message,
.status-banner {
  border: 1px solid #cfe2ff;
  background: #f5f9ff;
  color: var(--blue);
}

.error-message,
.error-banner {
  border: 1px solid #ffd4c7;
  background: #fff7f4;
  color: #bf3d1f;
}

.status-banner,
.error-banner {
  margin-bottom: 16px;
  border-radius: 8px;
  padding: 12px 14px;
  font-weight: 800;
}

.demo-route-button {
  width: 100%;
}

.start-companion {
  display: grid;
  gap: 18px;
}

.start-flow-card,
.zhihu-fit-card {
  padding: 24px;
}

.start-steps-list {
  display: grid;
  gap: 16px;
  margin: 20px 0 0;
  padding: 0;
  list-style: none;
}

.start-steps-list li {
  display: grid;
  grid-template-columns: 42px minmax(0, 1fr);
  gap: 13px;
  align-items: start;
}

.start-steps-list span {
  display: inline-grid;
  width: 42px;
  height: 42px;
  place-items: center;
  border-radius: 8px;
  background: #e9f7f4;
  color: #007a68;
  font-size: 13px;
  font-weight: 950;
}

.start-steps-list strong {
  display: block;
  margin-bottom: 4px;
  font-size: 17px;
}

.start-steps-list p {
  margin: 0;
  color: var(--muted);
  font-size: 14px;
  line-height: 1.65;
}

.zhihu-fit-card {
  background:
    linear-gradient(160deg, rgba(255, 255, 255, 0.96), rgba(255, 250, 237, 0.92)),
    linear-gradient(90deg, rgba(244, 184, 63, 0.12), rgba(44, 200, 255, 0.06));
}

.featured-starts {
  margin-top: 28px;
}

.featured-starts-header {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  gap: 18px;
  margin-bottom: 16px;
}

.featured-starts-header h2 {
  margin-bottom: 0;
  font-size: clamp(24px, 2.5vw, 34px);
}

.refresh-hotlist {
  min-height: 40px;
  border: 1px solid #b9d3ff;
  background: #fff;
  color: var(--blue);
  padding: 0 15px;
  font-size: 14px;
  font-weight: 850;
}

.refresh-hotlist:hover {
  background: var(--blue-soft);
  color: var(--blue-dark);
}

.refresh-hotlist:disabled {
  opacity: 0.55;
}

.featured-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 14px;
}

.featured-card {
  display: grid;
  grid-template-rows: auto auto minmax(46px, 1fr) auto;
  gap: 7px;
  min-height: 196px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.94);
  padding: 18px;
  color: var(--ink);
  text-align: left;
  box-shadow: 0 14px 34px rgba(20, 67, 128, 0.06);
}

.featured-card:hover {
  border-color: #9bc5ff;
  background: #fff;
  box-shadow: 0 22px 46px rgba(0, 102, 255, 0.1);
}

.featured-card .tag {
  display: inline-flex;
  justify-self: start;
  border-radius: 999px;
  background: #e9f7f4;
  color: #007a68;
  padding: 5px 9px;
  font-size: 12px;
  font-weight: 900;
}

.featured-card h4 {
  margin: 0;
  color: var(--ink);
  font-size: 16px;
  line-height: 1.45;
}

.featured-card p {
  display: -webkit-box;
  margin: 0;
  overflow: hidden;
  color: var(--muted);
  font-size: 13px;
  line-height: 1.55;
  -webkit-box-orient: vertical;
  -webkit-line-clamp: 3;
}

.featured-card small {
  color: var(--blue);
  font-size: 13px;
  font-weight: 900;
}

.hotlist-error {
  margin-bottom: 12px;
  border: 1px solid #ffd4c7;
  border-radius: 8px;
  background: #fff7f4;
  padding: 10px 12px;
  color: #bf3d1f;
  font-size: 14px;
  font-weight: 800;
}

.app-header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 18px;
  padding: 38px 0 16px;
}

.header-actions {
  display: flex;
  flex-wrap: wrap;
  justify-content: flex-end;
  gap: 10px;
}

.app-header h1 {
  max-width: 850px;
  font-size: clamp(30px, 4.5vw, 56px);
}

.progress-panel {
  display: grid;
  gap: 12px;
  margin-bottom: 18px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.94);
  padding: 16px 18px;
}

.progress-copy {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}

.progress-copy span {
  color: var(--muted);
  font-size: 14px;
}

.progress-track {
  height: 10px;
  overflow: hidden;
  border-radius: 999px;
  background: #e3efff;
}

.progress-track div {
  height: 100%;
  border-radius: inherit;
  background: linear-gradient(90deg, var(--blue), var(--cyan));
  transition: width 180ms ease;
}

.layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 380px;
  gap: 18px;
}

.reading-card,
.side-panel,
.preface,
.toc,
.authors-panel,
.route-timeline {
  padding: 24px;
}

.article-meta {
  margin-bottom: 14px;
  color: var(--muted);
  font-weight: 800;
}

.bridge {
  border: 1px solid #cfe2ff;
  border-left: 4px solid var(--blue);
  border-radius: 8px;
  background: #f5f9ff;
  padding: 16px;
}

.bridge p,
.curator-note p,
.interest-panel p,
.cover-concept-panel p {
  margin: 8px 0 0;
}

.curator-note,
.interest-panel,
.cover-concept-panel {
  margin-top: 16px;
  border: 1px solid var(--soft-line);
  border-radius: 8px;
  background: #fbfdff;
  padding: 16px;
}

.curator-note strong,
.interest-panel strong {
  color: var(--ink);
}

.direction-list {
  display: grid;
  gap: 10px;
}

.direction {
  width: 100%;
  min-height: 78px;
  border: 1px solid var(--line);
  background: #fff;
  color: var(--ink);
  padding: 14px;
  text-align: left;
}

.direction:hover,
.direction.selected {
  border-color: var(--blue);
  background: var(--blue-soft);
}

.direction span {
  display: block;
  margin-bottom: 6px;
  color: var(--blue);
  font-weight: 900;
}

.candidate {
  margin-top: 16px;
  border: 1px solid #cfe2ff;
  border-radius: 8px;
  background: #f5f9ff;
  padding: 16px;
}

.candidate button,
.primary-wide {
  width: 100%;
  padding: 0 16px;
}

.candidate-list {
  display: grid;
  gap: 10px;
  margin-top: 16px;
}

.candidate-card {
  display: grid;
  gap: 6px;
  width: 100%;
  min-height: 0;
  border: 1px solid var(--line);
  background: #fff;
  color: var(--ink);
  padding: 14px;
  text-align: left;
}

.candidate-card:hover,
.candidate-card.selected {
  border-color: var(--blue);
  background: var(--blue-soft);
  box-shadow: 0 10px 24px rgba(0, 102, 255, 0.1);
}

.candidate-card span {
  color: var(--blue);
  font-size: 13px;
  font-weight: 900;
}

.candidate-card strong {
  line-height: 1.35;
}

.candidate-card small,
.candidate-card em {
  color: var(--muted);
  font-size: 13px;
  font-style: normal;
  line-height: 1.55;
}

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

.route-strip {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 12px;
  margin-top: 18px;
}

.route-node {
  min-height: 112px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.86);
  padding: 12px;
}

.route-node.active {
  border-color: var(--blue);
  background: var(--blue-soft);
}

.route-node span,
.chapter-index,
.timeline-item span {
  display: inline-grid;
  width: 26px;
  height: 26px;
  place-items: center;
  border-radius: 999px;
  background: var(--blue);
  color: #fff;
  font-size: 13px;
  font-weight: 900;
}

.route-node p {
  margin: 10px 0 0;
  font-size: 13px;
  line-height: 1.45;
}

.header-subtitle {
  max-width: 760px;
  margin: -8px 0 0;
  color: var(--muted);
  font-size: 16px;
  line-height: 1.7;
}

.chapter-status {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 18px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.94);
  padding: 14px 16px;
  box-shadow: 0 18px 45px rgba(20, 67, 128, 0.06);
}

.chapter-marks {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  align-items: center;
}

.chapter-marks span {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: #fff;
  padding: 8px 12px;
  color: var(--muted);
  font-size: 13px;
  font-weight: 850;
}

.chapter-marks span::before {
  width: 8px;
  height: 8px;
  border-radius: 999px;
  background: #cbd7ea;
  content: "";
}

.chapter-marks span.complete {
  border-color: #bcd8ff;
  color: var(--blue);
}

.chapter-marks span.complete::before {
  background: var(--blue);
}

.chapter-marks span.current {
  border-color: var(--blue);
  color: var(--blue);
  box-shadow: 0 0 0 2px rgba(37, 99, 235, 0.15);
}

.book-ready,
.book-pending {
  border-radius: 999px;
  padding: 8px 12px;
  font-size: 13px;
}

.book-ready {
  background: var(--blue);
  color: #fff;
}

.book-pending {
  background: #fff7e6;
  color: #945b00;
}

.chapter-layout {
  display: grid;
  grid-template-columns: 230px minmax(0, 820px);
  gap: 22px;
  align-items: start;
}

.chapter-toc {
  position: sticky;
  top: 106px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.9);
  padding: 18px 16px;
  box-shadow: 0 18px 45px rgba(20, 67, 128, 0.06);
}

.chapter-toc h2 {
  margin-bottom: 16px;
  font-size: 18px;
}

.chapter-toc-list {
  display: grid;
  gap: 4px;
}

.chapter-toc-item {
  position: relative;
  display: grid;
  grid-template-columns: 26px minmax(0, 1fr);
  gap: 10px;
  padding: 7px 0 12px;
  color: var(--muted);
}

.chapter-toc-item::after {
  position: absolute;
  top: 34px;
  bottom: -8px;
  left: 12px;
  width: 1px;
  background: #d8e5f5;
  content: "";
}

.chapter-toc-item:last-child::after {
  display: none;
}

.chapter-toc-item span {
  position: relative;
  z-index: 1;
  display: inline-grid;
  width: 26px;
  height: 26px;
  place-items: center;
  border: 1px solid #cddcf0;
  border-radius: 999px;
  background: #fff;
  color: var(--muted);
  font-size: 12px;
  font-weight: 900;
}

.chapter-toc-item p {
  margin: 0;
  font-size: 13px;
  line-height: 1.45;
}

.chapter-toc-item strong {
  display: inline-block;
  margin-top: 2px;
  color: inherit;
  font-size: 13px;
  font-weight: 800;
}

.chapter-toc-item.active {
  color: var(--blue);
}

.chapter-toc-item.active span {
  border-color: var(--blue);
  background: var(--blue);
  color: #fff;
}

.chapter-toc-note {
  margin: 16px 0 0;
  border-top: 1px solid var(--soft-line);
  padding-top: 12px;
  color: var(--subtle);
  font-size: 13px;
  font-weight: 750;
}

.chapter-flow {
  display: grid;
  gap: 22px;
}

.flow-step {
  display: grid;
  gap: 14px;
}

.step-heading {
  display: grid;
  grid-template-columns: 34px minmax(0, 1fr);
  gap: 12px;
  align-items: start;
}

.step-heading > span {
  display: inline-grid;
  width: 34px;
  height: 34px;
  place-items: center;
  border-radius: 999px;
  background: var(--blue);
  color: #fff;
  font-weight: 900;
}

.step-heading h2 {
  margin-bottom: 4px;
  font-size: clamp(22px, 2.2vw, 30px);
}

.step-heading p {
  margin-bottom: 0;
  color: var(--muted);
  line-height: 1.6;
}

.chapter-reading-card {
  display: grid;
  gap: 16px;
}

.chapter-reading-card h3 {
  margin-bottom: 0;
  font-size: clamp(24px, 2.4vw, 34px);
}

.reading-note {
  margin: 0;
  padding: 12px 14px;
  border: 1px solid #d8e6fb;
  border-radius: 10px;
  background: #f7fbff;
  color: #53647f;
  line-height: 1.7;
}

.chapter-insight {
  display: grid;
  gap: 6px;
}

.chapter-insight strong {
  color: var(--ink);
  font-size: 15px;
}

.chapter-insight p {
  margin-bottom: 0;
  color: #2d3b56;
  line-height: 1.85;
}

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

.chapter-direction-list .direction {
  display: grid;
  gap: 8px;
  min-height: 158px;
  padding: 16px;
}

.chapter-direction-list .direction strong {
  color: var(--ink);
  font-size: 15px;
  line-height: 1.45;
}

.chapter-direction-list .direction small {
  color: var(--muted);
  font-size: 13px;
  line-height: 1.55;
}

.modal-backdrop {
  position: fixed;
  inset: 0;
  z-index: 20;
  display: grid;
  place-items: center;
  background: rgba(17, 26, 51, 0.34);
  padding: 28px;
  backdrop-filter: blur(6px);
}

.chapter-modal {
  position: relative;
  display: grid;
  grid-template-rows: auto auto minmax(0, 1fr) auto;
  gap: 14px;
  width: min(1080px, calc(100vw - 36px));
  max-height: min(780px, calc(100vh - 48px));
  overflow: hidden;
  border: 1px solid #cddcf0;
  border-radius: 8px;
  background: #fff;
  padding: 24px 24px 22px;
  box-shadow: 0 30px 80px rgba(9, 27, 61, 0.24);
}

.modal-close {
  position: absolute;
  top: 14px;
  right: 14px;
  width: 34px;
  min-height: 34px;
  border: 1px solid var(--line);
  background: #fff;
  color: var(--muted);
  font-size: 22px;
  line-height: 1;
}

.modal-close:hover {
  background: var(--blue-soft);
  color: var(--blue);
}

.chapter-modal-header {
  display: grid;
  grid-template-columns: minmax(230px, 0.7fr) minmax(0, 1fr);
  gap: 18px;
  padding-right: 34px;
  align-items: stretch;
}

.chapter-modal-header h2 {
  margin-bottom: 0;
  font-size: 30px;
}

.direction-recap {
  display: grid;
  gap: 5px;
  border: 1px solid var(--soft-line);
  border-radius: 8px;
  background: #f8fbff;
  padding: 12px 14px;
}

.direction-recap span,
.chapter-modal-summary span {
  color: var(--subtle);
  font-size: 12px;
  font-weight: 900;
}

.direction-recap strong {
  color: var(--ink);
  font-size: 18px;
  line-height: 1.35;
}

.direction-recap p,
.chapter-modal-summary p {
  margin-bottom: 0;
  color: var(--muted);
  font-size: 14px;
  line-height: 1.55;
}

.chapter-modal-summary {
  display: grid;
  grid-template-columns: minmax(260px, 0.82fr) minmax(0, 1fr);
  gap: 16px;
  align-items: center;
  border: 1px solid #cfe2ff;
  border-radius: 8px;
  background: linear-gradient(90deg, #f2f8ff 0%, #fbfdff 100%);
  padding: 12px 14px;
}

.chapter-modal-summary div {
  display: grid;
  gap: 4px;
}

.chapter-modal-summary strong {
  display: -webkit-box;
  overflow: hidden;
  color: var(--ink);
  font-size: 17px;
  line-height: 1.35;
  -webkit-box-orient: vertical;
  -webkit-line-clamp: 2;
}

.chapter-choice-list {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 12px;
  overflow: auto;
  padding-right: 4px;
}

.chapter-choice {
  display: grid;
  grid-template-rows: auto auto auto auto auto;
  gap: 10px;
  width: 100%;
  min-height: 0;
  border: 1px solid var(--line);
  background: #fff;
  color: var(--ink);
  padding: 15px;
  text-align: left;
  box-shadow: none;
}

.chapter-choice:hover,
.chapter-choice.selected {
  border-color: var(--blue);
  background: #f4f9ff;
  box-shadow: 0 14px 30px rgba(0, 102, 255, 0.1);
  transform: none;
}

.chapter-choice strong {
  display: block;
  font-size: 18px;
  line-height: 1.42;
}

.chapter-choice p {
  margin-bottom: 0;
  color: #34425d;
  font-size: 14px;
  line-height: 1.55;
}

.chapter-choice b {
  display: block;
  margin-bottom: 3px;
  color: var(--ink);
  font-size: 13px;
}

.choice-topline,
.signal-row {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  align-items: center;
}

.choice-index {
  display: inline-grid;
  place-items: center;
  width: 34px;
  height: 28px;
  border-radius: 8px;
  background: var(--ink);
  color: #fff;
  font-size: 12px;
  font-weight: 900;
}

.choice-source {
  border: 1px solid #dce7f7;
  border-radius: 999px;
  background: #fbfdff;
  padding: 4px 8px;
  color: var(--muted);
  font-size: 12px;
  font-weight: 840;
}

.choice-brief {
  display: -webkit-box;
  overflow: hidden;
  min-height: 44px;
  -webkit-box-orient: vertical;
  -webkit-line-clamp: 2;
}

.choice-reasons {
  display: grid;
  gap: 9px;
}

.choice-reasons p {
  overflow: hidden;
  border-left: 3px solid #cfe2ff;
  padding-left: 9px;
}

.choice-reasons span {
  display: -webkit-box;
  overflow: hidden;
  -webkit-box-orient: vertical;
  -webkit-line-clamp: 3;
}

.signal-row span {
  border: 1px solid #dce7f7;
  border-radius: 999px;
  background: #fbfdff;
  padding: 4px 8px;
  color: var(--muted);
  font-size: 12px;
  font-weight: 760;
}

.choice-footer {
  display: flex;
  flex-direction: column;
  gap: 10px;
  align-items: flex-start;
  justify-content: end;
}

.choice-footer .tag-row.compact {
  margin: 0;
}

.selected-note {
  margin-left: auto;
  border-radius: 999px;
  background: var(--blue);
  padding: 4px 8px;
  color: #fff;
  font-size: 12px;
  line-height: 1;
  font-weight: 900;
}

.chapter-modal-actions {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  border-top: 1px solid var(--soft-line);
  background: #fff;
  padding-top: 16px;
}

.chapter-modal-actions .primary-wide {
  width: auto;
  min-width: 180px;
}

.empty-next-step {
  border: 1px solid var(--line);
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.94);
  padding: 22px;
}

.book-detail-hero {
  display: grid;
  grid-template-columns: 360px minmax(0, 1fr);
  gap: 56px;
  align-items: center;
  padding: 42px 0 28px;
}

.detail-cover-wrap .mini-cover {
  max-width: 320px;
}

.created-at {
  margin: 16px 0 0;
  color: var(--subtle);
  font-size: 14px;
}

.detail-main h1 {
  max-width: 860px;
  font-size: clamp(36px, 5.2vw, 66px);
}

.detail-stats {
  max-width: 680px;
  margin: 26px 0 6px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.94);
  padding: 18px;
  box-shadow: 0 18px 45px rgba(20, 67, 128, 0.07);
}

.detail-stats span {
  min-width: 128px;
  display: grid;
  gap: 4px;
  border-right: 1px solid var(--line);
  color: var(--muted);
  padding: 6px 18px;
  font-weight: 800;
}

.detail-stats span:last-child {
  border-right: 0;
}

.detail-stats strong {
  color: var(--ink);
  font-size: 28px;
}

.detail-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.2fr) minmax(300px, 0.8fr);
  gap: 18px;
  align-items: start;
}

.toc {
  grid-row: span 2;
}

.cover-concept-panel {
  border: 1px solid var(--line);
  border-radius: 8px;
  background:
    linear-gradient(135deg, rgba(255, 255, 255, 0.96), rgba(235, 246, 255, 0.92)),
    linear-gradient(90deg, rgba(244, 184, 63, 0.08), rgba(0, 102, 255, 0.08));
  box-shadow: 0 18px 45px rgba(20, 67, 128, 0.07);
}

.chapter-list {
  display: grid;
  gap: 10px;
}

.chapter-row {
  display: grid;
  grid-template-columns: 34px minmax(0, 1fr) minmax(160px, auto);
  gap: 12px;
  align-items: center;
  border-bottom: 1px solid var(--soft-line);
  padding: 12px 0;
}

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

.chapter-row strong,
.author-item strong {
  display: block;
  line-height: 1.35;
}

.chapter-row small,
.author-item small {
  display: block;
  margin-top: 4px;
  color: var(--muted);
}

.author-list {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px;
}

.author-item {
  display: grid;
  grid-template-columns: 34px minmax(0, 1fr);
  gap: 10px;
  align-items: center;
  border: 1px solid var(--soft-line);
  border-radius: 8px;
  background: #fbfdff;
  padding: 10px;
}

.author-item > span {
  width: 34px;
  height: 34px;
  margin-left: 0;
}

.route-timeline {
  display: grid;
  gap: 10px;
}

.timeline-item {
  position: relative;
  display: grid;
  grid-template-columns: 30px minmax(0, 1fr);
  gap: 10px;
  align-items: start;
}

.timeline-item p {
  margin: 2px 0 0;
  color: var(--ink);
  font-size: 14px;
  line-height: 1.45;
}

.thinking-modal-backdrop {
  position: fixed;
  inset: 0;
  z-index: 30;
  display: grid;
  place-items: center;
  background: rgba(17, 26, 51, 0.55);
  padding: 28px;
  backdrop-filter: blur(8px);
  animation: thinkingFadeIn 300ms ease both;
}

.thinking-modal {
  display: grid;
  place-items: center;
  gap: 18px;
  width: min(420px, calc(100vw - 48px));
  border: 1px solid rgba(255, 255, 255, 0.2);
  border-radius: 16px;
  background:
    linear-gradient(160deg, rgba(255, 255, 255, 0.98), rgba(247, 251, 255, 0.96)),
    radial-gradient(circle at 70% 30%, rgba(0, 102, 255, 0.08), transparent 50%);
  padding: 42px 32px;
  box-shadow: 0 30px 80px rgba(9, 27, 61, 0.28);
  text-align: center;
  animation: thinkingSlideUp 400ms ease both;
}

.thinking-spinner {
  position: relative;
  width: 64px;
  height: 64px;
}

.thinking-ring {
  position: absolute;
  inset: 0;
  border: 3px solid rgba(0, 102, 255, 0.15);
  border-top-color: var(--blue);
  border-radius: 50%;
  animation: thinkingSpin 1s linear infinite;
}

.thinking-dots {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 5px;
}

.thinking-dots span {
  width: 7px;
  height: 7px;
  border-radius: 999px;
  background: var(--blue);
  animation: thinkingBounce 1.4s ease-in-out infinite both;
}

.thinking-dots span:nth-child(1) { animation-delay: -0.32s; }
.thinking-dots span:nth-child(2) { animation-delay: -0.16s; }

.thinking-title {
  color: var(--ink);
  font-size: 18px;
  font-weight: 900;
}

.thinking-quote-wrap {
  min-height: 56px;
  display: grid;
  place-items: center;
}

.thinking-quote {
  color: var(--muted);
  font-size: 15px;
  line-height: 1.65;
  transition: opacity 300ms ease;
}

.thinking-timer {
  color: var(--subtle);
  font-size: 13px;
  font-weight: 800;
}

@keyframes thinkingFadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

@keyframes thinkingSlideUp {
  from { opacity: 0; transform: translateY(18px); }
  to { opacity: 1; transform: translateY(0); }
}

@keyframes thinkingSpin {
  from { transform: rotate(0deg); }
  to { transform: rotate(360deg); }
}

@keyframes thinkingBounce {
  0%, 80%, 100% { transform: scale(0.6); opacity: 0.4; }
  40% { transform: scale(1); opacity: 1; }
}

@media (max-width: 1100px) {
  .topbar {
    grid-template-columns: 1fr;
    justify-items: start;
  }

  .nav-cta {
    justify-self: start;
  }

  .landing-hero,
  .hero-book-preview,
  .start-hero-card,
  .start-layout,
  .book-detail-hero,
  .detail-grid,
  .layout,
  .chapter-layout,
  .chapter-modal-header {
    grid-template-columns: 1fr;
  }

  .chapter-toc {
    position: static;
  }

  .chapter-direction-list {
    grid-template-columns: 1fr;
  }

  .chapter-choice-list {
    grid-template-columns: 1fr;
  }

  .shelf-grid,
  .feature-grid,
  .featured-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .flow-grid,
  .route-strip {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 720px) {
  .screen {
    width: min(100vw - 24px, 680px);
    padding-top: 12px;
  }

  h1 {
    font-size: 42px;
  }

  .brand-button span,
  .nav-cta {
    display: none;
  }

  .nav-links {
    width: 100%;
    justify-content: space-between;
    gap: 8px;
  }

  .landing-hero {
    padding: 28px;
  }

  .start-hero-card {
    margin-top: 24px;
    padding: 24px;
  }

  .start-hero-card h1 {
    font-size: 38px;
  }

  .featured-starts-header {
    align-items: flex-start;
    flex-direction: column;
  }

  .shelf-grid,
  .feature-grid,
  .featured-grid,
  .flow-grid,
  .route-strip,
  .chapter-direction-list,
  .empty-state,
  .chapter-row,
  .author-list,
  .input-row {
    grid-template-columns: 1fr;
  }

  .shelf-card {
    grid-template-columns: 118px minmax(0, 1fr);
    gap: 14px;
  }

  .empty-state {
    padding: 26px;
  }

  .section-heading.row,
  .progress-copy,
  .app-header,
  .header-actions {
    align-items: flex-start;
    flex-direction: column;
  }

  .input-row button {
    width: 100%;
  }

  .chapter-modal {
    padding: 18px;
  }

  .chapter-modal-summary {
    grid-template-columns: 1fr;
  }

  .chapter-modal-actions {
    position: static;
    flex-direction: column;
  }

  .chapter-modal-actions .primary-wide,
  .chapter-modal-actions .ghost-button {
    width: 100%;
  }
}

/* ===== 起点知识卡片（Start Knowledge Cards）===== */
.start-result-screen {
  padding: 46px 0 120px;
}

.start-result-header {
  max-width: 820px;
  margin-bottom: 28px;
}

.start-result-header h2 {
  margin-bottom: 10px;
  font-size: clamp(28px, 3.6vw, 42px);
}

.start-result-header p {
  margin: 0;
  color: var(--muted);
  font-size: 17px;
  line-height: 1.7;
}

.knowledge-cards {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(min(100%, 340px), 1fr));
  gap: 18px;
}

.knowledge-card {
  position: relative;
  display: grid;
  gap: 12px;
  min-height: 0;
  border: 1px solid var(--line);
  border-radius: 12px;
  background: rgba(255, 255, 255, 0.96);
  padding: 22px;
  text-align: left;
  cursor: pointer;
  transition:
    transform 180ms ease,
    border-color 180ms ease,
    box-shadow 180ms ease,
    background 180ms ease;
  box-shadow: 0 10px 28px rgba(20, 67, 128, 0.06);
}

.knowledge-card:hover {
  border-color: #9bc5ff;
  box-shadow: 0 18px 44px rgba(0, 102, 255, 0.1);
  transform: translateY(-2px);
}

.knowledge-card.selected {
  border-color: var(--blue);
  background: linear-gradient(160deg, #ffffff, #f0f7ff);
  box-shadow: 0 18px 44px rgba(0, 102, 255, 0.14);
}

.knowledge-card .card-header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 12px;
}

.card-index {
  display: inline-grid;
  width: 30px;
  height: 30px;
  place-items: center;
  border-radius: 999px;
  background: var(--blue-soft);
  color: var(--blue);
  font-size: 14px;
  font-weight: 900;
}

.knowledge-card.selected .card-index {
  background: var(--blue);
  color: #fff;
}

.card-concept {
  display: inline-flex;
  border-radius: 999px;
  background: #f3f8ff;
  padding: 5px 10px;
  color: var(--blue);
  font-size: 13px;
  font-weight: 900;
}

.knowledge-card .card-title {
  margin: 0;
  font-size: 18px;
  font-weight: 900;
  line-height: 1.35;
}

.card-summary {
  margin: 0;
  color: #2d3b56;
  font-size: 14px;
  line-height: 1.7;
}

.card-reason,
.card-value {
  margin: 0;
  color: var(--muted);
  font-size: 13px;
  line-height: 1.65;
}

.card-reason::before {
  content: "提取理由：";
  color: var(--subtle);
  font-weight: 800;
}

.card-value::before {
  content: "探索价值：";
  color: var(--subtle);
  font-weight: 800;
}

.card-query {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  margin-top: 2px;
  border-radius: 999px;
  background: #f3f8ff;
  padding: 5px 10px;
  color: var(--blue);
  font-size: 12px;
  font-weight: 900;
}

.card-query::before {
  content: "🔍";
  font-size: 11px;
}

.knowledge-card .selected-badge {
  position: absolute;
  top: 14px;
  right: 14px;
  display: none;
  border-radius: 999px;
  background: var(--blue);
  padding: 5px 10px;
  color: #fff;
  font-size: 12px;
  font-weight: 900;
}

.knowledge-card.selected .selected-badge {
  display: inline-flex;
}

.start-result-footer {
  position: fixed;
  right: 0;
  bottom: 0;
  left: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 16px;
  border-top: 1px solid rgba(210, 224, 244, 0.92);
  background: rgba(255, 255, 255, 0.92);
  padding: 14px 22px;
  backdrop-filter: blur(16px);
  box-shadow: 0 -10px 30px rgba(17, 49, 96, 0.08);
}

.start-result-footer button {
  padding: 0 28px;
  font-size: 16px;
}

.start-result-footer .ghost-button {
  border: 1px solid #b9d3ff;
  background: #fff;
  color: var(--blue);
}

.start-result-footer .ghost-button:hover {
  background: var(--blue-soft);
  color: var(--blue-dark);
}

@media (max-width: 1100px) {
  .knowledge-cards {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 720px) {
  .knowledge-cards {
    grid-template-columns: 1fr;
  }

  .start-result-footer {
    flex-direction: column;
    gap: 10px;
    padding: 12px 16px;
  }

  .start-result-footer button {
    width: 100%;
  }
}