:root {
  --bg: #f8f9fb;
  --surface: #ffffff;
  --surface-alt: #eef6fd;
  --line: #d8e2ec;
  --text: #17212b;
  --muted: #607286;
  --brand-red: #f45856;
  --brand-blue: #0f7ed6;
  --brand-blue-dark: #0566b4;
  --brand-blue-deep: #044f8d;
  --brand-blue-light: #e6f3fc;
  --brand-blue-pale: #f1f7fd;
  --gold: #eab308;
  --danger: #b42318;
  --shadow: 0 18px 48px rgba(5, 102, 180, 0.1);
}

* {
  box-sizing: border-box;
}

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

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

button,
input,
select {
  font: inherit;
  letter-spacing: 0;
}

button {
  min-height: 40px;
  border: 1px solid var(--brand-blue-dark);
  border-radius: 6px;
  background: var(--brand-blue-dark);
  color: #fff;
  padding: 0 16px;
  cursor: pointer;
}

button:hover {
  background: var(--brand-blue-deep);
}

button:disabled {
  cursor: not-allowed;
  border-color: #9aaabd;
  background: #9aaabd;
}

.hidden {
  display: none !important;
}

.visually-hidden {
  position: absolute !important;
  width: 1px !important;
  height: 1px !important;
  overflow: hidden !important;
  clip: rect(0 0 0 0) !important;
  clip-path: inset(50%) !important;
  white-space: nowrap !important;
}

.welcome-view {
  position: relative;
  min-height: 100vh;
  overflow: hidden;
  background: #ffffff;
}

.welcome-ellipse {
  position: absolute;
  display: block;
  user-select: none;
  pointer-events: none;
}

.welcome-ellipse-red {
  top: 0;
  left: 0;
  width: min(54vw, 935px);
  height: auto;
}

.welcome-ellipse-blue {
  top: 0;
  right: 0;
  width: min(54vw, 999px);
  height: auto;
}

.welcome-actions {
  position: absolute;
  top: 50%;
  left: 50%;
  z-index: 2;
  width: min(520px, calc(100vw - 48px));
  display: grid;
  gap: 10px;
  justify-items: center;
  transform: translate(-50%, -50%);
}

.welcome-brand-logo-full {
  display: block;
  width: min(340px, 100%);
  height: auto;
  margin-bottom: 14px;
  user-select: none;
}

.welcome-action-control,
.welcome-action-link {
  min-height: 0;
  width: min(340px, 100%);
  display: block;
  padding: 0;
  border: 0;
  border-radius: 0;
  background: transparent;
  box-shadow: none;
  cursor: pointer;
}

.welcome-action-control:hover,
.welcome-action-control:focus-visible,
.welcome-action-link:hover,
.welcome-action-link:focus-visible {
  background: transparent;
}

.welcome-action-control:focus-visible,
.welcome-action-link:focus-visible {
  outline: 3px solid rgba(15, 126, 214, 0.35);
  outline-offset: 4px;
}

.welcome-action-button {
  display: block;
  width: min(340px, 100%);
  height: auto;
  user-select: none;
}

.welcome-footer {
  position: absolute;
  right: 0;
  bottom: 0;
  left: 0;
  height: 84px;
  overflow: hidden;
}

.welcome-bottom-line {
  position: absolute;
  inset: 0;
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
  user-select: none;
  pointer-events: none;
}

.welcome-footer-content {
  position: relative;
  z-index: 1;
  height: 100%;
  display: grid;
  align-content: start;
  justify-items: center;
  color: #000000;
  text-align: center;
}

.welcome-friend-links {
  margin: 26px 0 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 20px;
  font-size: 12px;
  font-weight: 700;
  line-height: 1;
}

.welcome-youtube {
  color: #f14e4c;
}

.welcome-footer p {
  height: 12px;
  margin: 0;
  color: #b7b8be;
  font-size: 12px;
  line-height: 12px;
}

.login-view {
  min-height: 100vh;
  display: grid;
  place-items: center;
  padding: 32px;
  background:
    linear-gradient(180deg, rgba(15, 126, 214, 0.05) 0%, rgba(234, 103, 98, 0.04) 100%),
    #ffffff;
  overflow-x: hidden;
}

.login-panel {
  display: grid;
  width: min(600px, 100%);
  min-width: 0;
  min-height: 0;
  overflow: hidden;
  padding: 0;
  background: #ffffff;
  border: 1px solid #dee3e9;
  border-radius: 32px;
  box-shadow: rgba(15, 126, 214, 0.16) 0 1px 4px;
}

.login-content {
  display: grid;
  align-content: center;
  gap: 24px;
  padding: 44px;
}

.login-brand {
  display: grid;
  gap: 14px;
  text-align: left;
}

.login-brand-main {
  display: grid;
  grid-template-columns: 86px minmax(0, 1fr);
  align-items: center;
  gap: 18px;
}

.login-logo {
  display: block;
  width: 86px;
  height: 86px;
  border-radius: 24px;
  object-fit: cover;
  box-shadow: rgba(15, 126, 214, 0.18) 0 10px 22px;
}

.login-title {
  display: grid;
  gap: 2px;
  margin: 0;
  color: #0a1317;
  font-size: 48px;
  font-weight: 500;
  line-height: 1.17;
}

.login-title span {
  display: block;
}

.login-title .title-blue {
  color: var(--brand-blue);
}

.login-title .title-red {
  color: #ea6762;
}

.login-brand p {
  margin: 0;
  color: #5d6c7b;
  font-size: 16px;
}

.login-form {
  display: grid;
  gap: 16px;
}

label {
  display: grid;
  gap: 8px;
  margin: 0 0 16px;
  color: var(--muted);
  font-size: 14px;
}

.login-panel label {
  margin: 0;
}

.form-field {
  color: #1c1e21;
  font-weight: 700;
}

input,
select {
  min-height: 44px;
  width: 100%;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: #fff;
  color: var(--text);
  padding: 0 12px;
  outline: none;
}

.form-field input {
  min-height: 50px;
  border: 1px solid #ced0d4;
  border-radius: 8px;
  padding: 10px 12px;
  color: #1c1e21;
  background: #ffffff;
}

input:focus,
select:focus {
  border-color: var(--brand-blue);
  box-shadow: 0 0 0 3px rgba(15, 126, 214, 0.16);
}

.form-field input:focus {
  border-color: var(--brand-blue);
  box-shadow: 0 0 0 3px rgba(15, 126, 214, 0.16);
}

.login-panel button {
  width: 100%;
}

.primary-button {
  min-height: 52px;
  border: 0;
  border-radius: 999px;
  background: var(--brand-blue-dark);
  color: #ffffff;
  font-weight: 700;
  box-shadow: rgba(15, 126, 214, 0.22) 0 10px 22px;
}

.primary-button:hover {
  background: var(--brand-blue-deep);
}

.primary-button:disabled {
  background: #8595a4;
  box-shadow: none;
}

.message {
  min-height: 20px;
  margin: 0;
  color: #5d6c7b;
  font-size: 14px;
}

.login-status {
  color: var(--brand-blue-dark);
}

.login-status:not(:empty) {
  color: #ea6762;
}

.app-view {
  min-height: 100vh;
  display: grid;
  grid-template-rows: auto 1fr;
}

.topbar {
  min-height: 64px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 12px 22px;
  background: var(--surface);
  border-bottom: 1px solid var(--line);
}

.brand-line,
.account-line {
  display: flex;
  align-items: center;
  gap: 12px;
}

.brand-line img {
  width: 34px;
  height: 34px;
}

.brand-copy {
  min-width: 0;
  display: grid;
  gap: 2px;
}

.brand-line strong {
  font-size: 18px;
  line-height: 1.1;
}

.brand-title-red {
  color: #ea6762;
}

.brand-copy > span {
  color: var(--muted);
  font-size: 12px;
  font-weight: 700;
  line-height: 1.2;
}

.account-line button {
  min-height: 34px;
  padding: 0 12px;
  background: #fff;
  color: var(--brand-blue-dark);
}

.account-line button:hover {
  background: var(--surface-alt);
}

body.has-watch-history {
  overflow: hidden;
}

.watch-history-backdrop {
  position: fixed;
  inset: 0;
  z-index: 2147483100;
  display: grid;
  place-items: center;
  padding: 20px;
  background: rgba(10, 25, 40, 0.48);
  backdrop-filter: blur(3px);
}

.watch-history-panel {
  width: min(560px, 100%);
  max-height: min(72vh, 680px);
  display: grid;
  grid-template-rows: auto minmax(0, 1fr);
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: 12px;
  background: var(--surface);
  box-shadow: 0 24px 72px rgba(4, 79, 141, 0.2);
}

.watch-history-header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 24px;
  padding: 20px 20px 16px;
  border-bottom: 1px solid var(--line);
  background: var(--brand-blue-pale);
}

.watch-history-header h2 {
  margin: 0;
  color: var(--text);
  font-size: 21px;
  line-height: 1.25;
}

.watch-history-header p {
  margin: 6px 0 0;
  color: var(--muted);
  font-size: 13px;
  line-height: 1.45;
}

.watch-history-header .watch-history-close {
  width: 36px;
  min-width: 36px;
  min-height: 36px;
  padding: 0 0 3px;
  border-color: var(--line);
  border-radius: 50%;
  background: var(--surface);
  color: var(--brand-blue-dark);
  font-size: 25px;
  font-weight: 400;
  line-height: 1;
}

.watch-history-header .watch-history-close:hover,
.watch-history-header .watch-history-close:focus-visible {
  border-color: var(--brand-blue);
  background: var(--brand-blue-light);
}

.watch-history-header .watch-history-close:focus-visible,
.watch-history-item:focus-visible {
  outline: 3px solid rgba(15, 126, 214, 0.28);
  outline-offset: -3px;
}

.watch-history-list {
  min-height: 0;
  overflow: auto;
  overscroll-behavior: contain;
}

.watch-history-item {
  width: 100%;
  min-height: 0;
  display: grid;
  gap: 8px;
  padding: 15px 20px;
  border: 0;
  border-bottom: 1px solid var(--line);
  border-radius: 0;
  background: var(--surface);
  color: var(--text);
  text-align: left;
}

.watch-history-item:last-child {
  border-bottom: 0;
}

.watch-history-item:hover,
.watch-history-item:focus-visible {
  background: var(--brand-blue-pale);
}

.watch-history-course {
  overflow-wrap: anywhere;
  font-size: 16px;
  font-weight: 700;
  line-height: 1.4;
}

.watch-history-meta {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 5px 14px;
  color: var(--muted);
  font-size: 12px;
  line-height: 1.4;
}

.watch-history-meta time {
  font-variant-numeric: tabular-nums;
}

.watch-history-empty {
  min-height: 180px;
  display: grid;
  place-content: center;
  gap: 8px;
  padding: 32px 20px;
  color: var(--muted);
  text-align: center;
}

.watch-history-empty strong {
  color: var(--text);
  font-size: 16px;
}

.watch-history-empty span {
  font-size: 13px;
}

.workspace {
  display: grid;
  grid-template-columns: minmax(380px, 420px) minmax(0, 1fr);
  min-height: 0;
}

.library {
  min-height: 0;
  display: grid;
  grid-template-rows: auto minmax(0, 1fr);
  gap: 16px;
  padding: 18px;
  border-right: 1px solid var(--line);
  background: #f8fafc;
}

.standard-library {
  min-height: 0;
  display: grid;
  grid-template-rows: minmax(180px, 42vh) minmax(0, 1fr);
  gap: 16px;
}

.bipa-preview-entry {
  position: relative;
  width: 100%;
  min-height: 84px;
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  align-items: center;
  gap: 12px;
  padding: 12px 14px;
  overflow: hidden;
  border: 1px solid #bcd9f0;
  border-radius: 10px;
  background: transparent;
  color: var(--text);
  text-align: left;
  box-shadow: none;
}

.bipa-preview-entry:hover,
.bipa-preview-entry:focus-visible,
.bipa-preview-entry.is-active {
  border-color: var(--brand-blue);
  background: transparent;
  color: var(--text);
}

.bipa-preview-entry:focus-visible {
  outline: 3px solid rgba(15, 126, 214, 0.2);
  outline-offset: 2px;
}

.bipa-preview-entry.is-active {
  box-shadow: inset 4px 0 0 var(--brand-blue);
}

.bipa-preview-entry-copy {
  min-width: 0;
  display: grid;
  gap: 5px;
}

.bipa-preview-entry-copy strong {
  overflow-wrap: anywhere;
  font-size: 16px;
  line-height: 1.25;
}

.bipa-preview-entry-copy span {
  color: var(--muted);
  font-size: 12px;
  font-weight: 700;
}

.bipa-preview-entry-arrow {
  color: var(--brand-blue-dark);
  font-size: 28px;
  font-weight: 300;
  line-height: 1;
  transition: translate 160ms ease;
}

.bipa-preview-entry:hover .bipa-preview-entry-arrow,
.bipa-preview-entry:focus-visible .bipa-preview-entry-arrow {
  translate: 3px 0;
}

.library-block {
  min-height: 0;
  display: grid;
  grid-template-rows: auto 1fr;
  gap: 10px;
}

.library-block-courses {
  grid-template-rows: auto minmax(0, 1fr) auto;
}

.block-title,
.eyebrow {
  color: var(--muted);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0;
}

.list {
  min-height: 0;
  overflow: auto;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--surface);
}

.list-item {
  width: 100%;
  display: grid;
  gap: 4px;
  padding: 12px;
  border: 0;
  border-bottom: 1px solid var(--line);
  border-radius: 0;
  background: transparent;
  color: var(--text);
  text-align: left;
}

.list-item:last-child {
  border-bottom: 0;
}

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

.list-item:focus-visible {
  outline: 2px solid var(--brand-blue);
  outline-offset: -3px;
}

.list-item.is-active {
  background: var(--brand-blue-light);
  box-shadow: inset 3px 0 0 var(--brand-blue);
}

.item-title {
  min-width: 0;
  overflow-wrap: anywhere;
  font-weight: 700;
}

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

.course-pagination {
  display: grid;
  gap: 8px;
}

.course-pagination-summary {
  color: var(--muted);
  font-size: 12px;
  line-height: 1.3;
  text-align: center;
  font-variant-numeric: tabular-nums;
}

.course-pagination-controls {
  min-width: 0;
  display: grid;
  grid-template-columns: auto minmax(0, 1fr) auto;
  align-items: center;
  gap: 6px;
}

.course-pagination button {
  min-height: 38px;
  padding: 0 10px;
  border-color: var(--line);
  background: var(--surface);
  color: var(--brand-blue-dark);
  font-size: 12px;
  font-weight: 700;
  box-shadow: none;
}

.course-pagination button:hover,
.course-pagination button:focus-visible {
  border-color: var(--brand-blue);
  background: var(--brand-blue-pale);
  color: var(--brand-blue-dark);
}

.course-pagination button:focus-visible {
  outline: 3px solid rgba(15, 126, 214, 0.18);
  outline-offset: 1px;
}

.course-pagination button:disabled {
  border-color: var(--line);
  background: var(--surface-alt);
  color: var(--muted);
  opacity: 0.55;
}

.course-page-numbers {
  min-width: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 4px;
}

.course-pagination .course-page-button {
  width: 34px;
  padding: 0;
  font-variant-numeric: tabular-nums;
}

.course-pagination .course-page-button.is-active,
.course-pagination .course-page-button.is-active:hover {
  border-color: var(--brand-blue-dark);
  background: var(--brand-blue-dark);
  color: #ffffff;
}

.course-page-ellipsis {
  min-width: 14px;
  color: var(--muted);
  font-size: 13px;
  text-align: center;
}

.course-pagination-mobile-status {
  display: none;
  color: var(--muted);
  font-size: 12px;
  font-weight: 700;
  white-space: nowrap;
}

.lesson {
  min-width: 0;
  display: grid;
  align-content: start;
  padding: 18px 22px 22px;
}

.lesson-content {
  min-width: 0;
  display: grid;
  grid-template-rows: auto auto auto;
  align-content: start;
  gap: 16px;
}

.lesson-prompt {
  min-height: min(62vh, 720px);
  display: grid;
  place-content: center;
  justify-items: center;
  gap: 22px;
  padding: 48px 36px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--surface);
  text-align: center;
}

.lesson-prompt-logo {
  display: block;
  width: 96px;
  height: auto;
  object-fit: contain;
}

.lesson-prompt-message {
  max-width: 660px;
  margin: 0;
  color: var(--text);
  font-size: 17px;
  font-weight: 600;
  line-height: 1.8;
  text-align: left;
  text-wrap: pretty;
}

.lesson-prompt-warning,
.lesson-prompt-contact {
  font-weight: 800;
}

.lesson-prompt-warning {
  color: var(--brand-red);
}

.lesson-prompt-contact {
  color: var(--brand-blue);
}

.bipa-preview {
  min-width: 0;
  width: 100%;
}

.bipa-preview-hub {
  display: grid;
  gap: 18px;
}

.bipa-preview-hero {
  position: relative;
  min-height: 188px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 32px;
  padding: 30px 34px;
  overflow: hidden;
  border: 1px solid #c9deef;
  border-radius: 14px;
  background:
    radial-gradient(circle at 92% 15%, rgba(234, 103, 98, 0.2), transparent 30%),
    radial-gradient(circle at 77% 100%, rgba(15, 126, 214, 0.16), transparent 38%),
    linear-gradient(135deg, #ffffff 0%, #f3f9fe 72%, #fff7f6 100%);
  box-shadow: 0 14px 34px rgba(5, 102, 180, 0.09);
}

.bipa-preview-hero::after {
  content: "BIPA";
  position: absolute;
  right: 122px;
  bottom: -34px;
  color: rgba(15, 126, 214, 0.055);
  font-size: 116px;
  font-weight: 900;
  line-height: 1;
  pointer-events: none;
}

.bipa-preview-hero-copy {
  position: relative;
  z-index: 1;
  min-width: 0;
}

.bipa-preview-kicker {
  display: block;
  margin-bottom: 9px;
  color: var(--brand-blue-dark);
  font-size: 11px;
  font-weight: 900;
  letter-spacing: 0.12em;
}

.bipa-preview-hero h1 {
  margin: 0;
  color: #10283e;
  font-size: clamp(28px, 3vw, 40px);
  line-height: 1.15;
  text-wrap: balance;
}

.bipa-preview-hero p {
  max-width: 660px;
  margin: 12px 0 0;
  color: var(--muted);
  font-size: 15px;
  font-weight: 600;
  line-height: 1.7;
  text-wrap: pretty;
}

.bipa-preview-hero-side {
  position: relative;
  z-index: 1;
  min-width: 124px;
  display: grid;
  justify-items: end;
  gap: 12px;
}

.bipa-preview-total {
  width: 110px;
  height: 110px;
  display: grid;
  place-content: center;
  justify-items: center;
  border: 1px solid rgba(15, 126, 214, 0.2);
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.86);
  color: var(--brand-blue-dark);
  box-shadow: 0 10px 30px rgba(5, 102, 180, 0.1);
}

.bipa-preview-total strong {
  font-size: 38px;
  line-height: 1;
  font-variant-numeric: tabular-nums;
}

.bipa-preview-total span {
  margin-top: 5px;
  color: var(--muted);
  font-size: 11px;
  font-weight: 800;
}

.bipa-preview-exit,
.bipa-reader-back,
.bipa-reader-zoom button,
.bipa-reader-navigation button,
.bipa-reader-retry {
  min-height: 36px;
  padding: 0 13px;
  border-color: var(--line);
  border-radius: 7px;
  background: #ffffff;
  color: var(--brand-blue-dark);
  font-size: 12px;
  font-weight: 800;
  box-shadow: none;
}

.bipa-preview-exit:hover,
.bipa-preview-exit:focus-visible,
.bipa-reader-back:hover,
.bipa-reader-back:focus-visible,
.bipa-reader-zoom button:hover,
.bipa-reader-zoom button:focus-visible,
.bipa-reader-navigation button:hover,
.bipa-reader-navigation button:focus-visible,
.bipa-reader-retry:hover,
.bipa-reader-retry:focus-visible {
  border-color: var(--brand-blue);
  background: var(--brand-blue-pale);
  color: var(--brand-blue-dark);
}

.bipa-preview-exit:focus-visible,
.bipa-reader-back:focus-visible,
.bipa-reader-zoom button:focus-visible,
.bipa-reader-navigation button:focus-visible,
.bipa-reader-retry:focus-visible {
  outline: 3px solid rgba(15, 126, 214, 0.2);
  outline-offset: 2px;
}

.bipa-catalog-section {
  padding: 22px;
  border: 1px solid var(--line);
  border-radius: 12px;
  background: var(--surface);
}

.bipa-section-heading {
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 24px;
  margin-bottom: 16px;
}

.bipa-section-heading > div {
  min-width: 0;
}

.bipa-section-heading span {
  display: block;
  margin-bottom: 5px;
  color: var(--brand-blue-dark);
  font-size: 11px;
  font-weight: 900;
}

.bipa-section-heading h2 {
  margin: 0;
  color: var(--text);
  font-size: 22px;
  line-height: 1.25;
}

.bipa-level-grid {
  display: grid;
  grid-template-columns: repeat(7, minmax(88px, 1fr));
  gap: 10px;
}

.bipa-level-card {
  min-width: 0;
  min-height: 96px;
  display: grid;
  place-content: center;
  justify-items: center;
  gap: 7px;
  padding: 12px 8px;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: #ffffff;
  color: var(--text);
  box-shadow: none;
}

.bipa-level-card:hover,
.bipa-level-card:focus-visible {
  border-color: var(--brand-blue);
  background: var(--brand-blue-pale);
  color: var(--text);
}

.bipa-level-card:focus-visible {
  outline: 3px solid rgba(15, 126, 214, 0.18);
  outline-offset: 2px;
}

.bipa-level-card.is-active {
  border-color: var(--brand-blue);
  background: linear-gradient(155deg, #ffffff, var(--brand-blue-light));
  color: var(--brand-blue-deep);
  box-shadow: inset 0 -3px 0 var(--brand-blue);
}

.bipa-level-number {
  width: 36px;
  height: 36px;
  display: grid;
  place-items: center;
  border-radius: 50%;
  background: var(--brand-blue-light);
  color: var(--brand-blue-dark);
  font-size: 17px;
  font-weight: 900;
  font-variant-numeric: tabular-nums;
}

.bipa-level-card.is-active .bipa-level-number {
  background: var(--brand-blue-dark);
  color: #ffffff;
}

.bipa-level-card strong {
  font-size: 13px;
  line-height: 1.2;
}

.bipa-level-card small {
  color: var(--muted);
  font-size: 10px;
  font-weight: 700;
}

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

.bipa-material-card {
  min-width: 0;
  min-height: 78px;
  display: grid;
  grid-template-columns: auto minmax(0, 1fr) auto;
  align-items: center;
  gap: 13px;
  padding: 12px 14px;
  border: 1px solid var(--line);
  border-radius: 9px;
  background: #ffffff;
  color: var(--text);
  text-align: left;
  box-shadow: none;
}

.bipa-material-card:hover,
.bipa-material-card:focus-visible {
  border-color: var(--brand-blue);
  background: var(--brand-blue-pale);
  color: var(--text);
  translate: 0 -1px;
}

.bipa-material-card:focus-visible {
  outline: 3px solid rgba(15, 126, 214, 0.17);
  outline-offset: 2px;
}

.bipa-material-index {
  width: 38px;
  height: 38px;
  display: grid;
  place-items: center;
  border-radius: 9px;
  background: #edf4fa;
  color: var(--brand-blue-dark);
  font-size: 13px;
  font-weight: 900;
  font-variant-numeric: tabular-nums;
}

.bipa-material-copy {
  min-width: 0;
  display: grid;
  gap: 4px;
}

.bipa-material-copy small {
  color: var(--muted);
  font-size: 10px;
  font-weight: 800;
  text-transform: uppercase;
}

.bipa-material-copy strong {
  overflow-wrap: anywhere;
  font-size: 15px;
  line-height: 1.35;
}

.bipa-material-title-zh {
  color: var(--muted);
  font-size: 12px;
  font-weight: 650;
  line-height: 1.4;
  overflow-wrap: anywhere;
}

.bipa-material-action {
  color: var(--brand-blue-dark);
  font-size: 12px;
  font-weight: 800;
  white-space: nowrap;
}

.bipa-catalog-placeholder {
  grid-column: 1 / -1;
  min-height: 120px;
  display: grid;
  place-items: center;
  gap: 12px;
  padding: 24px;
  border: 1px dashed var(--line);
  border-radius: 9px;
  color: var(--muted);
  font-size: 13px;
  font-weight: 700;
  text-align: center;
}

.bipa-reader {
  min-width: 0;
  display: grid;
  gap: 12px;
}

.bipa-reader-toolbar {
  position: sticky;
  top: 0;
  z-index: 20;
  min-width: 0;
  display: grid;
  grid-template-columns: auto minmax(0, 1fr) auto;
  align-items: center;
  gap: 18px;
  padding: 12px 14px;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: rgba(255, 255, 255, 0.96);
  box-shadow: 0 8px 24px rgba(5, 102, 180, 0.1);
  backdrop-filter: blur(10px);
}

.bipa-reader-heading {
  min-width: 0;
}

.bipa-reader-heading span {
  display: block;
  margin-bottom: 3px;
  color: var(--brand-blue-dark);
  font-size: 10px;
  font-weight: 900;
}

.bipa-reader-heading h2 {
  margin: 0;
  overflow-wrap: anywhere;
  font-size: 18px;
  line-height: 1.3;
}

.bipa-reader-actions {
  min-width: 0;
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: 10px;
}

.bipa-reader-zoom {
  min-width: 0;
  display: grid;
  grid-template-columns: 40px minmax(56px, auto) 40px;
  align-items: stretch;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: 7px;
  background: #ffffff;
}

.bipa-reader-zoom button {
  width: 40px;
  min-width: 40px;
  min-height: 38px;
  padding: 0;
  border: 0;
  border-radius: 0;
  font-size: 20px;
  line-height: 1;
}

.bipa-reader-zoom button:disabled,
.bipa-reader-zoom button:disabled:hover {
  border: 0;
  background: var(--surface-alt);
  color: #91a0ad;
  opacity: 1;
}

.bipa-reader-zoom output {
  min-width: 56px;
  display: grid;
  place-items: center;
  padding: 0 8px;
  border-right: 1px solid var(--line);
  border-left: 1px solid var(--line);
  color: var(--text);
  font-size: 12px;
  font-weight: 900;
  font-variant-numeric: tabular-nums;
  white-space: nowrap;
}

.bipa-reader-navigation {
  display: flex;
  gap: 7px;
}

.bipa-reader-navigation button:disabled {
  border-color: var(--line);
  background: var(--surface-alt);
  color: var(--muted);
  opacity: 0.55;
}

.bipa-reader-viewport {
  position: relative;
  min-height: 640px;
  padding: 22px;
  overflow: hidden;
  border: 1px solid #ccd8e3;
  border-radius: 10px;
  background: #e9eef3;
}

.bipa-reader-status {
  min-height: 560px;
  display: grid;
  place-content: center;
  justify-items: center;
  gap: 9px;
  padding: 40px 20px;
  color: var(--muted);
  text-align: center;
}

.bipa-reader-status strong {
  color: var(--text);
  font-size: 16px;
}

.bipa-reader-status > span:last-of-type {
  font-size: 12px;
}

.bipa-reader-spinner {
  width: 34px;
  height: 34px;
  margin-bottom: 4px;
  border: 3px solid #c9d8e5;
  border-top-color: var(--brand-blue);
  border-radius: 50%;
  animation: bipa-reader-spin 800ms linear infinite;
}

.bipa-reader-status.is-error .bipa-reader-spinner {
  display: none;
}

@keyframes bipa-reader-spin {
  to {
    rotate: 360deg;
  }
}

.bipa-reader-article {
  --bipa-reader-font-size: 15px;
  position: relative;
  z-index: 2;
  width: min(900px, 100%);
  min-height: 1000px;
  margin: 0 auto;
  padding: clamp(32px, 5vw, 64px);
  overflow-wrap: anywhere;
  border: 1px solid #dce3ea;
  background: #ffffff;
  color: #1f2937;
  font-family: "Songti SC", "Noto Serif CJK SC", "Source Han Serif SC", "SimSun", serif;
  font-size: var(--bipa-reader-font-size);
  line-height: 1.78;
  box-shadow: 0 16px 42px rgba(20, 38, 54, 0.13);
}

.bipa-reader-article[data-zoom="80"] {
  --bipa-reader-font-size: 12px;
}

.bipa-reader-article[data-zoom="90"] {
  --bipa-reader-font-size: 13.5px;
}

.bipa-reader-article[data-zoom="100"] {
  --bipa-reader-font-size: 15px;
}

.bipa-reader-article[data-zoom="110"] {
  --bipa-reader-font-size: 16.5px;
}

.bipa-reader-article[data-zoom="120"] {
  --bipa-reader-font-size: 18px;
}

.bipa-reader-article[data-zoom="130"] {
  --bipa-reader-font-size: 19.5px;
}

.bipa-reader-article[data-zoom="140"] {
  --bipa-reader-font-size: 21px;
}

.bipa-reader-article[data-zoom="150"] {
  --bipa-reader-font-size: 22.5px;
}

.bipa-reader-article .bipa-doc-kicker {
  margin: 0 0 10px;
  color: #2e74b5;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  font-size: 0.7333em;
  font-weight: 900;
  letter-spacing: 0.05em;
}

.bipa-reader-article .bipa-doc-title {
  margin: 0;
  color: #0b2545;
  font-size: 3.2em;
  line-height: 1.12;
}

.bipa-reader-article .bipa-doc-subtitle {
  margin: 9px 0 28px;
  color: #687483;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  font-size: 0.8667em;
  font-weight: 700;
}

.bipa-reader-article h2 {
  margin: 32px 0 12px;
  padding-top: 5px;
  color: #2e74b5;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  font-size: 1.4em;
  line-height: 1.35;
}

.bipa-reader-article h3 {
  margin: 22px 0 9px;
  color: #183f63;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  font-size: 1.1333em;
  line-height: 1.45;
}

.bipa-reader-article .bipa-doc-paragraph {
  margin: 0 0 12px;
}

.bipa-reader-article .bipa-doc-list {
  margin: 8px 0 17px;
  padding-left: 24px;
}

.bipa-reader-article .bipa-doc-list li {
  margin: 0 0 7px;
  padding-left: 3px;
}

.bipa-reader-article .bipa-doc-note {
  margin: 8px 0 14px;
  padding: 10px 13px;
  border-left: 3px solid #8ebee2;
  background: #f3f7fb;
  color: #5f6f7e;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  font-size: 0.8em;
  line-height: 1.6;
}

.bipa-reader-article .bipa-doc-source {
  width: fit-content;
  margin: 19px 0 7px;
  padding: 4px 9px;
  border-radius: 999px;
  background: #e7f2fb;
  color: #175f96;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  font-size: 0.7333em;
  font-weight: 900;
}

.bipa-doc-table-scroll {
  max-width: 100%;
  margin: 13px 0 24px;
  overflow-x: auto;
  overscroll-behavior-inline: contain;
  border: 1px solid #b8c3cf;
  border-radius: 6px;
  background: #ffffff;
}

.bipa-doc-table-scroll:focus-visible {
  outline: 3px solid rgba(15, 126, 214, 0.2);
  outline-offset: 2px;
}

.bipa-doc-table {
  width: 100%;
  min-width: 720px;
  border-collapse: collapse;
  table-layout: fixed;
  font-size: 0.8667em;
  line-height: 1.58;
}

.bipa-doc-table th,
.bipa-doc-table td {
  padding: 10px 11px;
  border-right: 1px solid #b8c3cf;
  border-bottom: 1px solid #b8c3cf;
  vertical-align: top;
  text-align: left;
}

.bipa-doc-table th:last-child,
.bipa-doc-table td:last-child {
  border-right: 0;
}

.bipa-doc-table tbody tr:last-child td {
  border-bottom: 0;
}

.bipa-doc-table th {
  background: #e8eef5;
  color: #0b2545;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  font-size: 0.9231em;
  text-align: center;
}

.bipa-doc-table th:nth-child(1),
.bipa-doc-table td:nth-child(1) {
  width: 20%;
}

.bipa-doc-table th:nth-child(2),
.bipa-doc-table td:nth-child(2) {
  width: 15%;
  text-align: center;
}

.bipa-doc-table th:nth-child(3),
.bipa-doc-table td:nth-child(3) {
  width: 20%;
}

.bipa-doc-table th:nth-child(4),
.bipa-doc-table td:nth-child(4) {
  width: 45%;
}

.bipa-reader-watermark {
  position: absolute;
  inset: 0;
  z-index: 3;
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  align-content: space-around;
  justify-items: center;
  gap: 50px 18px;
  padding: 80px 12px;
  overflow: hidden;
  pointer-events: none;
  user-select: none;
}

.bipa-reader-watermark span {
  max-width: 260px;
  color: rgba(20, 68, 105, 0.085);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  font-size: 11px;
  font-weight: 800;
  line-height: 1.45;
  text-align: center;
  rotate: -23deg;
  white-space: nowrap;
}

body.is-bipa-preview .lesson-prompt,
body.is-bipa-preview .lesson-content {
  display: none !important;
}

.player-shell {
  position: relative;
  width: 100%;
  max-height: min(62vh, 720px);
  aspect-ratio: 16 / 9;
  background: #0a111a;
  border: 1px solid #172331;
  border-radius: 8px;
  overflow: hidden;
}

body.has-player-browser-fullscreen {
  overflow: hidden;
}

.player-shell.is-browser-fullscreen {
  position: fixed;
  inset: 0;
  z-index: 2147483000;
  width: 100vw;
  height: 100vh;
  height: 100dvh;
  max-height: none;
  aspect-ratio: auto;
  border: 0;
  border-radius: 0;
}

video {
  width: 100%;
  height: 100%;
  display: block;
  background: #0a111a;
  cursor: pointer;
  user-select: none;
}

.aliyun-player,
.aliyun-player .prism-player,
.aliyun-player video {
  width: 100%;
  height: 100%;
  background: #0a111a;
}

.aliyun-player {
  display: block;
  user-select: none;
}

.aliyun-player .prism-player {
  position: relative;
}

.aliyun-player .prism-controlbar {
  z-index: 5 !important;
}

.aliyun-player .prism-player .prism-controlbar {
  height: 48px !important;
  z-index: 12 !important;
  background: linear-gradient(180deg, rgba(7, 15, 24, 0), rgba(7, 15, 24, 0.9));
}

.aliyun-player .prism-player .prism-controlbar .prism-controlbar-bg {
  height: 44px !important;
  background: rgba(7, 15, 24, 0.78) !important;
  backdrop-filter: blur(10px);
}

.aliyun-player .prism-player .prism-play-btn,
.aliyun-player .prism-player .prism-fullscreen-btn,
.aliyun-player .prism-player .prism-volume .volume-icon {
  position: relative;
  width: 32px !important;
  height: 32px !important;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.14) !important;
  background-image: none !important;
  color: #ffffff;
  touch-action: manipulation;
}

.aliyun-player .prism-player .prism-play-btn::before,
.aliyun-player .prism-player .prism-fullscreen-btn::before,
.aliyun-player .prism-player .prism-volume .volume-icon::before {
  content: "";
  position: absolute;
  inset: 0;
  margin: auto;
  display: block;
}

.aliyun-player .prism-player .prism-play-btn::before {
  width: 0;
  height: 0;
  border-top: 8px solid transparent;
  border-bottom: 8px solid transparent;
  border-left: 12px solid #ffffff;
  transform: translateX(2px);
}

.aliyun-player .prism-player .prism-play-btn.playing::before {
  width: 13px;
  height: 16px;
  border: 0;
  background: linear-gradient(90deg, #ffffff 0 38%, transparent 38% 62%, #ffffff 62% 100%);
  transform: none;
}

.aliyun-player .prism-player .prism-fullscreen-btn::before {
  width: 17px;
  height: 17px;
  background:
    linear-gradient(#ffffff, #ffffff) left top / 8px 2px no-repeat,
    linear-gradient(#ffffff, #ffffff) left top / 2px 8px no-repeat,
    linear-gradient(#ffffff, #ffffff) right top / 8px 2px no-repeat,
    linear-gradient(#ffffff, #ffffff) right top / 2px 8px no-repeat,
    linear-gradient(#ffffff, #ffffff) left bottom / 8px 2px no-repeat,
    linear-gradient(#ffffff, #ffffff) left bottom / 2px 8px no-repeat,
    linear-gradient(#ffffff, #ffffff) right bottom / 8px 2px no-repeat,
    linear-gradient(#ffffff, #ffffff) right bottom / 2px 8px no-repeat;
}

.aliyun-player .prism-player .prism-fullscreen-btn.fullscreen::before {
  width: 15px;
  height: 15px;
  background:
    linear-gradient(#ffffff, #ffffff) 3px 3px / 8px 2px no-repeat,
    linear-gradient(#ffffff, #ffffff) 3px 3px / 2px 8px no-repeat,
    linear-gradient(#ffffff, #ffffff) right 3px top 3px / 8px 2px no-repeat,
    linear-gradient(#ffffff, #ffffff) right 3px top 3px / 2px 8px no-repeat,
    linear-gradient(#ffffff, #ffffff) left 3px bottom 3px / 8px 2px no-repeat,
    linear-gradient(#ffffff, #ffffff) left 3px bottom 3px / 2px 8px no-repeat,
    linear-gradient(#ffffff, #ffffff) right 3px bottom 3px / 8px 2px no-repeat,
    linear-gradient(#ffffff, #ffffff) right 3px bottom 3px / 2px 8px no-repeat;
}

.aliyun-player .prism-player .prism-volume .volume-icon::before,
#aliyunPlayer .prism-volume .volume-icon::before {
  width: 16px;
  height: 16px;
  background: #ffffff;
  -webkit-clip-path: polygon(0 34%, 34% 34%, 78% 0, 78% 100%, 34% 66%, 0 66%);
  clip-path: polygon(0 34%, 34% 34%, 78% 0, 78% 100%, 34% 66%, 0 66%);
  transform: translateX(-3px);
}

.aliyun-player .prism-player .prism-volume .volume-icon::after,
#aliyunPlayer .prism-volume .volume-icon::after {
  content: "";
  position: absolute;
  top: 6px;
  right: 4px;
  width: 11px;
  height: 20px;
  background: radial-gradient(
    circle at left center,
    transparent 0 4px,
    #ffffff 4.2px 5.8px,
    transparent 6px 8px,
    #ffffff 8.2px 9.8px,
    transparent 10px
  );
}

.aliyun-player .prism-player .prism-volume .volume-icon.mute::after,
.aliyun-player .prism-player .prism-volume .volume-icon .long-horizontal,
.aliyun-player .prism-player .prism-volume .volume-icon .short-horizontal,
#aliyunPlayer .prism-volume .volume-icon .long-horizontal,
#aliyunPlayer .prism-volume .volume-icon .short-horizontal {
  display: none !important;
}

.aliyun-player .prism-player .prism-volume .volume-icon.mute::after,
#aliyunPlayer .prism-volume .volume-icon.mute::after {
  display: block !important;
  top: 10px;
  right: 4px;
  width: 11px;
  height: 11px;
  background:
    linear-gradient(45deg, transparent 42%, #ffffff 43% 57%, transparent 58%),
    linear-gradient(-45deg, transparent 42%, #ffffff 43% 57%, transparent 58%);
}

.aliyun-player .prism-player .prism-play-btn:hover,
.aliyun-player .prism-player .prism-fullscreen-btn:hover,
.aliyun-player .prism-player .prism-volume .volume-icon:hover,
#aliyunPlayer .prism-volume .volume-icon:hover {
  background: rgba(255, 255, 255, 0.22) !important;
}

.aliyun-player .prism-player .prism-time-display,
.aliyun-player .prism-player .prism-time-display .current-time {
  color: #ffffff !important;
}

.aliyun-player .prism-player .prism-progress,
.aliyun-player .prism-player .prism-liveshift-progress {
  bottom: 44px !important;
  height: 5px !important;
  background: rgba(255, 255, 255, 0.26) !important;
}

.aliyun-player .prism-player .prism-progress .prism-progress-played,
.aliyun-player .prism-player .prism-liveshift-progress .prism-progress-played {
  background: var(--brand-blue) !important;
}

#aliyunPlayer .prism-controlbar {
  height: 48px !important;
  z-index: 12 !important;
  background: linear-gradient(180deg, rgba(7, 15, 24, 0), rgba(7, 15, 24, 0.9));
}

#aliyunPlayer .prism-controlbar .prism-controlbar-bg {
  height: 44px !important;
  background: rgba(7, 15, 24, 0.78) !important;
  backdrop-filter: blur(10px);
}

#aliyunPlayer .prism-play-btn,
#aliyunPlayer .prism-fullscreen-btn,
#aliyunPlayer .prism-volume .volume-icon {
  position: relative;
  width: 32px !important;
  height: 32px !important;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.14) !important;
  background-image: none !important;
  color: #ffffff;
  touch-action: manipulation;
}

#aliyunPlayer .prism-play-btn::before,
#aliyunPlayer .prism-fullscreen-btn::before,
#aliyunPlayer .prism-volume .volume-icon::before {
  content: "";
  position: absolute;
  inset: 0;
  margin: auto;
  display: block;
}

#aliyunPlayer .prism-play-btn::before {
  width: 0;
  height: 0;
  border-top: 8px solid transparent;
  border-bottom: 8px solid transparent;
  border-left: 12px solid #ffffff;
  transform: translateX(2px);
}

#aliyunPlayer .prism-play-btn.playing::before {
  width: 13px;
  height: 16px;
  border: 0;
  background: linear-gradient(90deg, #ffffff 0 38%, transparent 38% 62%, #ffffff 62% 100%);
  transform: none;
}

#aliyunPlayer .prism-fullscreen-btn::before {
  width: 17px;
  height: 17px;
  background:
    linear-gradient(#ffffff, #ffffff) left top / 8px 2px no-repeat,
    linear-gradient(#ffffff, #ffffff) left top / 2px 8px no-repeat,
    linear-gradient(#ffffff, #ffffff) right top / 8px 2px no-repeat,
    linear-gradient(#ffffff, #ffffff) right top / 2px 8px no-repeat,
    linear-gradient(#ffffff, #ffffff) left bottom / 8px 2px no-repeat,
    linear-gradient(#ffffff, #ffffff) left bottom / 2px 8px no-repeat,
    linear-gradient(#ffffff, #ffffff) right bottom / 8px 2px no-repeat,
    linear-gradient(#ffffff, #ffffff) right bottom / 2px 8px no-repeat;
}

#aliyunPlayer .prism-fullscreen-btn.fullscreen::before {
  width: 15px;
  height: 15px;
  background:
    linear-gradient(#ffffff, #ffffff) 3px 3px / 8px 2px no-repeat,
    linear-gradient(#ffffff, #ffffff) 3px 3px / 2px 8px no-repeat,
    linear-gradient(#ffffff, #ffffff) right 3px top 3px / 8px 2px no-repeat,
    linear-gradient(#ffffff, #ffffff) right 3px top 3px / 2px 8px no-repeat,
    linear-gradient(#ffffff, #ffffff) left 3px bottom 3px / 8px 2px no-repeat,
    linear-gradient(#ffffff, #ffffff) left 3px bottom 3px / 2px 8px no-repeat,
    linear-gradient(#ffffff, #ffffff) right 3px bottom 3px / 8px 2px no-repeat,
    linear-gradient(#ffffff, #ffffff) right 3px bottom 3px / 2px 8px no-repeat;
}

#aliyunPlayer .prism-time-display,
#aliyunPlayer .prism-time-display .current-time {
  color: #ffffff !important;
}

#aliyunPlayer .prism-progress,
#aliyunPlayer .prism-liveshift-progress {
  bottom: 44px !important;
  height: 5px !important;
  background: rgba(255, 255, 255, 0.26) !important;
}

#aliyunPlayer .prism-progress .prism-progress-played,
#aliyunPlayer .prism-liveshift-progress .prism-progress-played {
  background: var(--brand-blue) !important;
}

#aliyunPlayer .prism-volume .volume-icon {
  cursor: pointer;
}

#aliyunPlayer .prism-volume-control {
  bottom: 42px !important;
  width: 36px !important;
  height: 124px !important;
  transform: translateX(3px);
  overflow: visible;
  border: 1px solid rgba(255, 255, 255, 0.14);
  border-radius: 10px;
  background: rgba(7, 15, 24, 0.92) !important;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.38) !important;
  backdrop-filter: blur(10px);
}

#aliyunPlayer .prism-volume-control .volume-control-icon {
  display: none !important;
}

#aliyunPlayer .prism-volume-control .volume-range {
  left: 15px !important;
  bottom: 14px !important;
  width: 4px !important;
  height: 94px !important;
  border-radius: 999px !important;
  background: rgba(255, 255, 255, 0.28) !important;
  box-shadow: none !important;
}

#aliyunPlayer .prism-volume-control .volume-value {
  border-radius: 999px !important;
  background: var(--brand-blue) !important;
}

#aliyunPlayer .prism-volume-control .volume-cursor {
  left: -6px !important;
  width: 16px !important;
  height: 16px !important;
  border: 2px solid #ffffff;
  background: var(--brand-blue) !important;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.36);
}

#aliyunPlayer .prism-volume-control .volume-cursor:hover {
  background: #ffffff !important;
}

.drm-controls-overlay {
  position: absolute;
  left: 14px;
  right: 90px;
  bottom: 4px;
  z-index: 14;
  display: flex;
  align-items: center;
  gap: 8px;
  pointer-events: none;
}

.drm-control-button {
  width: 34px;
  height: 34px;
  min-height: 34px;
  display: grid;
  place-items: center;
  padding: 0;
  border: 0;
  border-radius: 999px;
  background: rgba(7, 15, 24, 0.82);
  color: #ffffff;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
  backdrop-filter: blur(10px);
  pointer-events: auto;
  touch-action: manipulation;
  -webkit-tap-highlight-color: transparent;
}

.drm-control-button:hover,
.drm-control-button:focus-visible {
  background: rgba(7, 15, 24, 0.94);
  outline: 2px solid rgba(255, 255, 255, 0.42);
  outline-offset: 2px;
}

.drm-play-toggle::before {
  content: "";
  width: 0;
  height: 0;
  border-top: 8px solid transparent;
  border-bottom: 8px solid transparent;
  border-left: 12px solid #ffffff;
  transform: translateX(2px);
}

.drm-play-toggle.is-playing::before {
  width: 12px;
  height: 15px;
  border: 0;
  background: linear-gradient(90deg, #ffffff 0 38%, transparent 38% 62%, #ffffff 62% 100%);
  transform: none;
}

.playback-rate-picker {
  position: relative;
  min-width: 0;
  pointer-events: auto;
}

.playback-rate-button {
  width: 44px;
  min-width: 44px;
  padding: 0 7px;
  border-radius: 8px;
  font-size: 12px;
  font-weight: 800;
  font-variant-numeric: tabular-nums;
  white-space: nowrap;
}

.drm-control-button.playback-rate-button {
  width: 44px;
  min-width: 44px;
}

.drm-controls-overlay .playback-rate-picker {
  margin-left: auto;
}

.drm-controls-overlay .playback-rate-menu {
  right: 0;
  left: auto;
  transform: none;
}

.playback-rate-menu {
  position: absolute;
  bottom: calc(100% + 8px);
  left: 50%;
  z-index: 30;
  min-width: 88px;
  display: grid;
  gap: 2px;
  padding: 6px;
  border: 1px solid rgba(255, 255, 255, 0.16);
  border-radius: 10px;
  background: rgba(7, 15, 24, 0.96);
  box-shadow: 0 14px 36px rgba(0, 0, 0, 0.38);
  backdrop-filter: blur(10px);
  transform: translateX(-50%);
}

.playback-rate-menu button {
  width: 100%;
  min-height: 32px;
  padding: 0 10px;
  border: 0;
  border-radius: 6px;
  background: transparent;
  color: rgba(255, 255, 255, 0.9);
  font-size: 12px;
  font-weight: 700;
  font-variant-numeric: tabular-nums;
  white-space: nowrap;
}

.playback-rate-menu button:hover,
.playback-rate-menu button:focus-visible {
  background: rgba(255, 255, 255, 0.12);
  outline: none;
}

.playback-rate-menu button:focus-visible {
  box-shadow: inset 0 0 0 2px #85c6ff;
}

.playback-rate-menu button[aria-checked="true"] {
  background: var(--brand-blue);
  color: #ffffff;
}

.is-drm-player .watermark-layer {
  z-index: 3;
}

.is-drm-player .player-loading {
  z-index: 6;
}

.player-loading {
  position: absolute;
  inset: 0;
  z-index: 6;
  display: grid;
  place-items: center;
  padding: 20px;
  background:
    linear-gradient(180deg, rgba(9, 16, 25, 0.78), rgba(9, 16, 25, 0.42)),
    rgba(9, 16, 25, 0.54);
  color: #fff;
  pointer-events: none;
}

.player-loading.is-compact {
  inset: 14px 14px auto auto;
  width: min(330px, calc(100% - 28px));
  display: block;
  padding: 0;
  background: transparent;
}

.loading-panel {
  width: min(380px, 100%);
  display: grid;
  grid-template-columns: auto 1fr auto;
  gap: 10px 12px;
  align-items: center;
  padding: 16px;
  border: 1px solid rgba(255, 255, 255, 0.18);
  border-radius: 8px;
  background: rgba(7, 15, 24, 0.86);
  box-shadow: 0 16px 42px rgba(0, 0, 0, 0.28);
  backdrop-filter: blur(8px);
}

.player-loading.is-compact .loading-panel {
  width: 100%;
  grid-template-columns: auto 1fr auto;
  gap: 6px 9px;
  padding: 9px 10px;
  border-color: rgba(255, 255, 255, 0.14);
  background: rgba(7, 15, 24, 0.74);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.22);
  backdrop-filter: blur(6px);
}

.loader-ring {
  width: 30px;
  height: 30px;
  border: 3px solid rgba(255, 255, 255, 0.22);
  border-top-color: var(--brand-blue);
  border-radius: 50%;
  animation: loader-spin 0.9s linear infinite;
}

.player-loading.is-compact .loader-ring {
  width: 18px;
  height: 18px;
  border-width: 2px;
}

.loading-copy {
  min-width: 0;
  display: grid;
  gap: 4px;
}

.loading-copy strong {
  font-size: 15px;
  line-height: 1.3;
}

.player-loading.is-compact .loading-copy strong {
  font-size: 12px;
}

.loading-copy span {
  color: rgba(255, 255, 255, 0.72);
  font-size: 13px;
  line-height: 1.45;
  overflow-wrap: anywhere;
}

.player-loading.is-compact .loading-copy span {
  font-size: 11px;
  line-height: 1.25;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.loading-meter {
  grid-column: 1 / -1;
  height: 7px;
  overflow: hidden;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.16);
}

.player-loading.is-compact .loading-meter {
  height: 4px;
}

.loading-meter span {
  width: 0%;
  height: 100%;
  display: block;
  border-radius: inherit;
  background: linear-gradient(90deg, var(--brand-blue), #85c6ff);
  transition: width 180ms ease;
}

.loading-meter span.is-indeterminate {
  width: 42%;
  animation: loading-slide 1.15s ease-in-out infinite;
}

.loading-percent {
  min-width: 48px;
  color: rgba(255, 255, 255, 0.9);
  font-size: 14px;
  font-weight: 700;
  text-align: right;
}

.player-loading.is-compact .loading-percent {
  min-width: 36px;
  font-size: 12px;
}

@keyframes loader-spin {
  to {
    transform: rotate(360deg);
  }
}

@keyframes loading-slide {
  0% {
    transform: translateX(-115%);
  }

  50% {
    transform: translateX(55%);
  }

  100% {
    transform: translateX(235%);
  }
}

.watermark-layer {
  position: absolute;
  inset: 0;
  z-index: 3;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  grid-auto-rows: minmax(72px, 1fr);
  align-items: center;
  pointer-events: none;
  opacity: 0.06;
}

.watermark-layer span {
  color: rgba(255, 255, 255, 0.82);
  font-size: 13px;
  font-weight: 700;
  line-height: 1.35;
  text-align: center;
  transform: rotate(-18deg);
  text-shadow:
    0 1px 2px rgba(0, 0, 0, 0.9),
    0 0 8px rgba(0, 0, 0, 0.55);
  user-select: none;
  overflow-wrap: anywhere;
}

.custom-controls {
  position: absolute;
  right: 14px;
  bottom: 14px;
  left: 14px;
  z-index: 5;
  display: grid;
  grid-template-columns: auto auto minmax(80px, 1fr) auto auto minmax(58px, 92px) auto auto;
  align-items: center;
  gap: 10px;
  padding: 10px 12px;
  border: 1px solid rgba(255, 255, 255, 0.12);
  border-radius: 999px;
  background: rgba(7, 15, 24, 0.76);
  box-shadow: 0 12px 34px rgba(0, 0, 0, 0.28);
  backdrop-filter: blur(10px);
}

.control-button {
  width: 34px;
  height: 34px;
  min-height: 34px;
  display: grid;
  place-items: center;
  padding: 0;
  border: 0;
  border-radius: 999px;
  background: transparent;
  color: rgba(255, 255, 255, 0.9);
  font-size: 18px;
  line-height: 1;
}

.control-button:hover,
.control-button:focus-visible {
  background: rgba(255, 255, 255, 0.14);
}

.control-button:focus-visible {
  outline: 2px solid #85c6ff;
  outline-offset: 2px;
}

.control-button:hover {
  outline: none;
}

.time-label {
  min-width: 42px;
  color: rgba(255, 255, 255, 0.86);
  font-size: 13px;
  font-weight: 700;
  line-height: 1;
  text-align: center;
  font-variant-numeric: tabular-nums;
}

.seek-slider,
.volume-slider {
  min-height: 24px;
  padding: 0;
  border: 0;
  border-radius: 0;
  background: transparent;
  accent-color: var(--brand-blue);
  cursor: pointer;
}

.seek-slider:focus-visible,
.volume-slider:focus-visible {
  box-shadow: none;
  outline: 2px solid #85c6ff;
  outline-offset: 2px;
}

.seek-slider::-webkit-slider-runnable-track,
.volume-slider::-webkit-slider-runnable-track {
  height: 5px;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.2);
}

.seek-slider::-webkit-slider-thumb,
.volume-slider::-webkit-slider-thumb {
  width: 16px;
  height: 16px;
  margin-top: -5.5px;
}

.seek-slider::-moz-range-track,
.volume-slider::-moz-range-track {
  height: 5px;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.2);
}

.lesson-header {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  align-items: start;
}

.lesson-header h2 {
  margin: 4px 0 0;
  font-size: 22px;
  line-height: 1.2;
  overflow-wrap: anywhere;
}

.course-description {
  margin: 0;
  max-width: 900px;
  color: var(--muted);
  line-height: 1.7;
  overflow-wrap: anywhere;
}

.empty-state {
  padding: 16px;
  color: var(--muted);
}

@media (min-width: 861px) and (max-width: 1180px) {
  .bipa-reader-toolbar {
    grid-template-columns: auto minmax(0, 1fr);
  }

  .bipa-reader-actions {
    grid-column: 1 / -1;
    justify-content: space-between;
  }

  .bipa-reader-article .bipa-doc-title {
    font-size: 2.8em;
  }
}

@media (max-width: 860px) {
  .topbar {
    align-items: flex-start;
    flex-direction: column;
  }

  .account-line {
    width: 100%;
    flex-wrap: wrap;
  }

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

  .library {
    border-right: 0;
    border-bottom: 1px solid var(--line);
    grid-template-rows: auto auto;
  }

  .standard-library {
    grid-template-rows: auto auto;
  }

  .list {
    max-height: 34vh;
  }

  .lesson {
    padding: 16px;
  }

  .lesson-prompt {
    min-height: 360px;
  }

  .bipa-preview-hero {
    padding: 26px;
  }

  .bipa-preview-hero::after {
    right: 90px;
  }

  .bipa-level-grid {
    grid-template-columns: repeat(4, minmax(82px, 1fr));
  }

  .bipa-reader-toolbar {
    grid-template-columns: auto minmax(0, 1fr);
  }

  .bipa-reader-actions {
    grid-column: 1 / -1;
    justify-content: space-between;
  }

  .bipa-reader-article .bipa-doc-title {
    font-size: 2.5em;
  }

  .bipa-reader-viewport {
    padding: 14px;
  }

  .bipa-reader-watermark {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .custom-controls {
    right: 10px;
    bottom: 10px;
    left: 10px;
    grid-template-columns: auto auto minmax(60px, 1fr) auto auto auto auto;
    gap: 7px;
    padding: 8px 9px;
  }

  .volume-slider {
    display: none;
  }
}

@media (max-width: 520px) {
  .watch-history-backdrop {
    align-items: end;
    padding: 12px;
  }

  .watch-history-panel {
    max-height: 82svh;
    border-radius: 12px;
  }

  .watch-history-header {
    gap: 16px;
    padding: 18px 16px 14px;
  }

  .watch-history-item {
    padding: 14px 16px;
  }

  .watch-history-meta {
    display: grid;
  }

  .login-view {
    min-height: 100svh;
    align-content: start;
    place-items: start stretch;
    align-items: start;
    justify-items: stretch;
    padding: max(16px, env(safe-area-inset-top)) 14px 16px;
  }

  .login-panel {
    width: min(100%, 440px);
    margin: 0 auto;
    border-radius: 24px;
  }

  .login-content {
    gap: 18px;
    padding: 24px;
  }

  .login-brand-main {
    grid-template-columns: 58px minmax(0, 1fr);
    gap: 12px;
  }

  .login-logo {
    width: 58px;
    height: 58px;
    border-radius: 16px;
  }

  .login-title {
    font-size: 32px;
    line-height: 1.18;
  }

  .login-brand p {
    font-size: 15px;
    line-height: 1.45;
  }

  .login-form {
    gap: 14px;
  }

  .primary-button {
    min-height: 46px;
  }

  .course-pagination-controls {
    gap: 8px;
  }

  .course-pagination button {
    min-height: 44px;
    padding: 0 12px;
  }

  .course-page-numbers .course-page-button,
  .course-page-numbers .course-page-ellipsis {
    display: none;
  }

  .course-pagination-mobile-status {
    display: inline;
  }

  .lesson-header {
    display: grid;
  }

  .lesson-prompt {
    gap: 22px;
    padding: 32px 20px;
  }

  .lesson-prompt-logo {
    width: 80px;
  }

  .lesson-prompt-message {
    font-size: 16px;
    line-height: 1.8;
  }

  .bipa-preview-entry {
    min-height: 76px;
  }

  .bipa-preview-hero {
    min-height: 0;
    display: grid;
    gap: 20px;
    padding: 24px 20px;
  }

  .bipa-preview-hero::after {
    right: -8px;
    bottom: -18px;
    font-size: 88px;
  }

  .bipa-preview-hero-side {
    width: 100%;
    min-width: 0;
    display: flex;
    align-items: center;
    justify-content: space-between;
  }

  .bipa-preview-total {
    width: auto;
    height: auto;
    display: flex;
    align-items: baseline;
    gap: 7px;
    padding: 9px 12px;
    border-radius: 9px;
  }

  .bipa-preview-total strong {
    font-size: 24px;
  }

  .bipa-preview-total span {
    margin: 0;
  }

  .bipa-catalog-section {
    padding: 18px 14px;
  }

  .bipa-section-heading {
    display: grid;
    gap: 7px;
  }

  .bipa-level-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .bipa-level-card {
    min-height: 78px;
    grid-template-columns: auto 1fr;
    grid-template-rows: auto auto;
    justify-items: start;
    justify-content: stretch;
    column-gap: 9px;
    padding: 10px;
  }

  .bipa-level-number {
    grid-row: 1 / 3;
    align-self: center;
  }

  .bipa-material-grid {
    grid-template-columns: 1fr;
  }

  .bipa-material-card {
    min-height: 72px;
    padding: 11px;
  }

  .bipa-material-action {
    font-size: 0;
  }

  .bipa-material-action::after {
    content: "›";
    font-size: 24px;
    font-weight: 400;
  }

  .bipa-reader-toolbar {
    position: static;
    grid-template-columns: 1fr;
    gap: 10px;
  }

  .bipa-reader-back {
    justify-self: start;
  }

  .bipa-reader-actions {
    grid-column: auto;
    width: 100%;
    display: grid;
    grid-template-columns: 1fr;
    gap: 10px;
  }

  .bipa-reader-zoom {
    width: 100%;
    grid-template-columns: 44px minmax(0, 1fr) 44px;
  }

  .bipa-reader-zoom button {
    width: 44px;
    min-width: 44px;
    min-height: 44px;
  }

  .bipa-reader-navigation {
    grid-column: auto;
    justify-content: stretch;
  }

  .bipa-reader-navigation button {
    flex: 1;
    min-height: 42px;
  }

  .bipa-reader-viewport {
    min-height: 520px;
    padding: 0;
    overflow: visible;
    border-radius: 8px;
  }

  .bipa-reader-status {
    min-height: 520px;
  }

  .bipa-reader-article {
    --bipa-reader-font-size: 14px;
    min-height: 820px;
    padding: 30px 20px;
    border: 0;
    line-height: 1.75;
    box-shadow: none;
  }

  .bipa-reader-article[data-zoom="80"] {
    --bipa-reader-font-size: 11.2px;
  }

  .bipa-reader-article[data-zoom="90"] {
    --bipa-reader-font-size: 12.6px;
  }

  .bipa-reader-article[data-zoom="100"] {
    --bipa-reader-font-size: 14px;
  }

  .bipa-reader-article[data-zoom="110"] {
    --bipa-reader-font-size: 15.4px;
  }

  .bipa-reader-article[data-zoom="120"] {
    --bipa-reader-font-size: 16.8px;
  }

  .bipa-reader-article[data-zoom="130"] {
    --bipa-reader-font-size: 18.2px;
  }

  .bipa-reader-article[data-zoom="140"] {
    --bipa-reader-font-size: 19.6px;
  }

  .bipa-reader-article[data-zoom="150"] {
    --bipa-reader-font-size: 21px;
  }

  .bipa-reader-article .bipa-doc-kicker {
    font-size: 0.7857em;
  }

  .bipa-reader-article .bipa-doc-title {
    font-size: 2.4286em;
  }

  .bipa-reader-article .bipa-doc-subtitle {
    font-size: 0.9286em;
  }

  .bipa-reader-article h2 {
    margin-top: 28px;
    font-size: 1.3571em;
  }

  .bipa-reader-article h3 {
    font-size: 1.1429em;
  }

  .bipa-reader-article .bipa-doc-note {
    font-size: 0.8571em;
  }

  .bipa-reader-article .bipa-doc-source {
    font-size: 0.7857em;
  }

  .bipa-doc-table {
    font-size: 0.9286em;
  }

  .bipa-doc-table-scroll {
    margin-right: -8px;
    margin-left: -8px;
  }

  .bipa-reader-watermark {
    grid-template-columns: 1fr;
    gap: 42px;
  }

  .watermark-layer {
    grid-template-columns: repeat(2, 1fr);
  }

  .player-loading {
    padding: 12px;
  }

  .loading-panel {
    grid-template-columns: auto 1fr;
  }

  .loading-percent {
    grid-column: 1 / -1;
    min-width: 0;
    text-align: left;
  }

  .custom-controls {
    bottom: 8px;
    grid-template-columns: auto auto auto minmax(0, 1fr) auto auto auto;
    grid-template-areas:
      "seek seek seek seek seek seek seek"
      "play current duration spacer mute rate fullscreen";
    column-gap: 5px;
    row-gap: 6px;
    padding: 7px 8px;
    border-radius: 8px;
  }

  #playToggleButton {
    grid-area: play;
  }

  #currentTimeLabel {
    grid-area: current;
  }

  .custom-controls .seek-slider {
    width: 100%;
    grid-area: seek;
  }

  #durationLabel {
    grid-area: duration;
  }

  #muteButton {
    grid-area: mute;
  }

  .custom-controls .playback-rate-picker {
    grid-area: rate;
  }

  #fullscreenButton {
    grid-area: fullscreen;
  }

  .time-label {
    min-width: 36px;
    font-size: 12px;
  }

  .control-button {
    width: 30px;
    height: 30px;
    min-height: 30px;
  }

  .control-button.playback-rate-button {
    width: 38px;
    min-width: 38px;
    padding: 0 4px;
    font-size: 11px;
  }

  .aliyun-player .prism-player .prism-controlbar {
    height: 52px !important;
  }

  #aliyunPlayer .prism-controlbar {
    height: 52px !important;
  }

  .aliyun-player .prism-player .prism-controlbar .prism-controlbar-bg {
    height: 48px !important;
  }

  #aliyunPlayer .prism-controlbar .prism-controlbar-bg {
    height: 48px !important;
  }

  .aliyun-player .prism-player .prism-progress,
  .aliyun-player .prism-player .prism-liveshift-progress,
  #aliyunPlayer .prism-progress,
  #aliyunPlayer .prism-liveshift-progress {
    bottom: 48px !important;
  }

  .aliyun-player .prism-player .prism-play-btn,
  .aliyun-player .prism-player .prism-fullscreen-btn,
  .aliyun-player .prism-player .prism-volume .volume-icon,
  #aliyunPlayer .prism-play-btn,
  #aliyunPlayer .prism-fullscreen-btn,
  #aliyunPlayer .prism-volume .volume-icon {
    width: 34px !important;
    height: 34px !important;
  }

  .aliyun-player .prism-player .prism-time-display,
  #aliyunPlayer .prism-time-display {
    max-width: calc(100vw - 150px);
    overflow: hidden;
    color: #ffffff !important;
    font-size: 11px !important;
    white-space: nowrap;
  }

  .aliyun-player .prism-player .prism-volume,
  #aliyunPlayer .prism-volume {
    display: none !important;
  }

  .drm-controls-overlay {
    left: 12px;
    right: 52px;
    bottom: 2px;
    gap: 7px;
  }

  .drm-control-button {
    width: 36px;
    height: 36px;
    min-height: 36px;
  }

  .drm-control-button.playback-rate-button {
    width: 44px;
    min-width: 44px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .bipa-preview-entry-arrow,
  .bipa-material-card {
    transition: none;
  }

  .bipa-reader-spinner {
    animation-duration: 1600ms;
  }
}

@media print {
  body.is-bipa-preview .app-view {
    display: none !important;
  }

  body.is-bipa-preview::after {
    content: "BIPA 预习材料仅供东东学员站内查看";
    display: block;
    padding: 48px;
    color: #17212b;
    font-size: 18px;
    text-align: center;
  }
}