:root {
  --primary-red: #AD0800;
  --primary-red-dark: #8A0600;
  --accent-orange: #ED6525;
  --ink: #131313;
  --muted: #666666;
  --light-muted: #999999;
  --line: #E5E5E5;
  --warm-line: #f0ded5;
  --soft: #fff7f3;
  --soft-strong: #fff1ea;
  --page-width: 1443px;
  --content-width: 900px;
  --sidebar-width: 265px;
  --gap: 35px;
}
* { box-sizing: border-box; }
html,
body {
  margin: 0;
  color: var(--ink);
  font-family: "Inter", "PingFang SC", "Microsoft YaHei", sans-serif;
  background: #fff;
  line-height: 1.6;
}
img {
  max-width: 100%;
  height: auto;
  display: block;
}
a {
  color: inherit;
  text-decoration: none;
}
button,
input {
  font-family: inherit;
}
button {
  border: none;
  cursor: pointer;
}
.header {
  background: #fff;
  position: sticky;
  top: 0;
  z-index: 1000;
  filter: drop-shadow(0px 0px 11px rgba(215, 215, 215, 0.329));
}
.header-wrapper {
  display: flex;
  flex-direction: column;
}
.header-top-bar {
  display: none;
}
.header-nav-bar {
  max-width: var(--page-width);
  margin: 0 auto;
  padding: 7px 121px;
  display: flex;
  align-items: center;
  gap: 30px;
  width: 100%;
  background: #fff;
}
.logo img {
  height: 32px;
  width: auto;
}
.nav-menu {
  display: flex;
  align-items: center;
  gap: 35px;
  margin-left: 100px;
}
.nav-link {
  font-size: 16px;
  font-weight: 400;
  color: #000;
  padding: 8px 0;
  white-space: nowrap;
}
.nav-link:hover {
  color: var(--primary-red);
  font-weight: 700;
}
.nav-link.active {
  color: var(--primary-red);
  font-weight: 700;
}
.search-container {
  flex: 1;
  display: flex;
  justify-content: flex-end;
}
.search-box {
  display: flex;
  align-items: center;
  background: linear-gradient(135deg, #ED6525 0%, #EA1D1D 24%, #B80D0D 100%);
  border-radius: 11px;
  width: 454px;
  height: 38px;
  padding: 2px;
  gap: 0;
  overflow: hidden;
}
.search-input {
  width: 376px;
  flex-shrink: 0;
  height: 100%;
  margin: 0;
  padding: 0 15px;
  border: none;
  border-radius: 10px;
  background: #fff;
  color: #000;
  font-size: 14px;
  outline: none;
}
.search-input::placeholder {
  color: #9F9B9B;
}
.search-btn {
  flex: 1;
  height: 100%;
  padding: 0;
  background: transparent;
  color: #fff;
  font-size: 15px;
  font-weight: 400;
  white-space: nowrap;
  text-align: center;
}
.mobile-logo {
  display: none;
}

.page-wrapper {
  max-width: var(--page-width);
  margin: 0 auto;
  padding: 0 121px;
}
.main-container {
  display: flex;
  align-items: flex-start;
  gap: var(--gap);
  padding: 38px 0 44px;
  position: relative;
}
.content-left {
  flex: 1 1 auto;
  max-width: var(--content-width);
  min-width: 0;
}
.sidebar-right {
  width: var(--sidebar-width);
  flex-shrink: 0;
  position: sticky;
  top: 91px;
  height: fit-content;
}

.course-hero {
  padding: 6px 0 28px;
  margin-bottom: 8px;
}
.course-hero h1 {
  margin: 0 0 10px;
  font-size: 32px;
  line-height: 1.25;
  font-weight: 700;
  letter-spacing: 0;
}
p { margin: 0; }
.course-subtitle {
  max-width: 900px;
  color: #333333;
  font-size: 16px;
  line-height: 1.75;
}
.hero-teacher-tip {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 6px;
  margin-top: 12px;
  color: #666;
  font-size: 14px;
  line-height: 1.6;
}
.hero-teacher-tip strong {
  color: var(--primary-red);
  font-weight: 700;
}
.hero-teacher-tip a {
  color: #333;
  font-weight: 400;
}
.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 20px;
}
.hero-action-helper {
  max-width: 760px;
  margin-top: 10px;
  color: #777;
  font-size: 14px;
  line-height: 1.65;
}
.primary-action,
.secondary-action {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 140px;
  height: 34px;
  border-radius: 8px;
  border: 0;
  cursor: pointer;
  font-size: 15px;
  font-weight: 400;
}
.primary-action {
  color: #fff;
  background: var(--primary-red);
}
.secondary-action {
  color: var(--primary-red);
  background: #fff;
  border: 1px solid #ecd7cc;
}
.section {
  padding: 34px 0;
}
.section-anchor {
  scroll-margin-top: 78px;
}
.outline-section,
.teacher-section {
  scroll-margin-top: 78px;
}
.section h2 {
  margin: 0 0 20px;
  padding-bottom: 9px;
  border-bottom: 1px solid var(--primary-red);
  font-size: 22px;
  line-height: 1.35;
  font-weight: 700;
}
.section p,
.section li {
  font-size: 16px;
  line-height: 1.85;
}
.meta-row {
  margin-top: 18px;
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
}
.pill {
  display: inline-flex;
  border: 1px solid #ecd7cc;
  background: #fffdfb;
  border-radius: 999px;
  padding: 5px 12px;
  color: #5f4034;
  font-size: 14px;
  font-weight: 400;
}
.course-hero .meta-row {
  gap: 0;
  margin-top: 16px;
  color: #5f5049;
}
.course-hero .pill {
  border: 0;
  background: transparent;
  border-radius: 0;
  padding: 0;
  color: #5f5049;
  font-size: 15px;
  line-height: 1.6;
}
.course-hero .pill:not(:last-child)::after {
  content: "|";
  margin: 0 12px;
  color: #d8d0cb;
}
.rich-list {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
  padding: 0;
  margin: 0;
  list-style: none;
}
.rich-list li,
.module-card,
.outline-card {
  border: 1px solid #f0ded5;
  background: #fffdfb;
  border-radius: 8px;
  padding: 14px 16px;
}
.benefit-extra {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  margin-top: 12px;
  border: 0;
  background: transparent;
}
.benefit-extra summary {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 7px 12px;
  border: 1px solid #eeeeee;
  border-radius: 999px;
  background: #fff;
  color: #5f5049;
  font-size: 14px;
  font-weight: 400;
  cursor: pointer;
  list-style: none;
}
.benefit-extra summary::-webkit-details-marker {
  display: none;
}
.benefit-extra-summary-open {
  display: none;
}
.benefit-extra[open] summary {
  order: 2;
  margin-top: 14px;
}
.benefit-extra[open] .benefit-extra-summary-closed {
  display: none;
}
.benefit-extra[open] .benefit-extra-summary-open {
  display: inline;
}
.benefit-extra summary::after {
  content: '+';
  color: #8f8a87;
}
.benefit-extra[open] summary::after {
  content: '-';
}
.benefit-extra .rich-list {
  width: 100%;
  order: 1;
  margin-top: 12px;
}
.module-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
}
.module-card strong {
  color: var(--primary-red);
  margin-right: 8px;
}
.content-band {
  display: grid;
  gap: 10px;
}
.paragraph-card {
  color: #131313;
  background: transparent;
  padding: 0;
  border-radius: 0;
}
.fact-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
  margin-top: 16px;
}
.fact-card {
  border: 1px solid #f0ded5;
  border-radius: 8px;
  padding: 12px 14px;
  background: #fffdfb;
}
.fact-label {
  color: var(--muted);
  font-size: 13px;
  font-weight: 800;
  margin-bottom: 4px;
}
.course-fit-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
}
.course-fit-card,
.course-faq-item {
  border: 1px solid #f0ded5;
  border-radius: 8px;
  background: #fffdfb;
  padding: 14px 16px;
}
.course-fit-card strong {
  display: block;
  margin-bottom: 5px;
  color: #8f170d;
  font-size: 15px;
  line-height: 1.5;
}
.course-fit-card p,
.course-faq-item p {
  color: #333333;
  font-size: 15px;
  line-height: 1.75;
}
.course-boundary-note {
  margin-top: 12px;
  color: #6f625d;
  font-size: 14px;
  line-height: 1.75;
}
.course-faq-list {
  display: grid;
  gap: 12px;
}
.course-faq-item h3 {
  margin: 0 0 7px;
  color: #171717;
  font-size: 16px;
  line-height: 1.55;
  font-weight: 700;
}
.fact-list {
  display: grid;
  gap: 6px;
  margin: 0;
  padding-left: 18px;
}
.fact-list li {
  line-height: 1.7;
}
.outline-list {
  display: grid;
  gap: 14px;
}
.outline-card {
  line-height: 1.7;
  scroll-margin-top: 78px;
}
.outline-card p,
.outline-card li {
  line-height: 1.7;
}
.outline-card h3 {
  margin: 0 0 8px;
  font-size: 18px;
}
.outline-subtitle {
  margin-top: 14px;
  font-weight: 900;
  color: #7a4936;
  font-size: 14px;
}
.outline-card ul {
  margin: 10px 0 0;
  padding-left: 20px;
}
.outline-item-list-leading {
  margin-bottom: 10px;
}
.outline-item-groups {
  display: grid;
  gap: 12px;
  margin-top: 8px;
}
.outline-item-group {
  padding-left: 0;
}
.outline-item-group-title {
  margin: 10px 0 6px;
  color: #2c2521;
  font-weight: 800;
  line-height: 1.65;
  font-size: 17px;
}
.outline-item-group-list {
  margin-top: 4px;
  padding-left: 20px;
}
.outline-subsections {
  display: grid;
  gap: 12px;
  margin-top: 14px;
}
.outline-subsection {
  padding-left: 0;
}
.outline-subsection-title {
  font-weight: 900;
  color: #2c2521;
}
.outline-subsection ul {
  margin-top: 6px;
  padding-left: 18px;
}
.outline-card li.outline-numbered-item {
  list-style: none;
  margin-left: -18px;
  font-weight: 400;
}
.outline-card li.outline-support-item {
  list-style: none;
  margin: 6px 0;
  padding: 0;
  color: #5f5049;
}
.outline-card li.outline-expanded-item {
  list-style: none;
  margin: 4px 0 8px;
}
.outline-expanded-title {
  display: block;
  margin-bottom: 2px;
  color: #2c2521;
  font-weight: 700;
}
.outline-card .outline-nested-list {
  margin: 2px 0 0;
  padding-left: 22px;
}
.outline-card .outline-nested-list li {
  list-style: circle;
  margin: 2px 0;
  line-height: 1.65;
}
.outline-card li.outline-subheading-item {
  list-style: none;
  margin: 10px 0 6px -18px;
  font-weight: 800;
  color: #2c2521;
  font-size: 17px;
}
.version-intro {
  margin-bottom: 18px;
  color: #3f302b;
  font-size: 16px;
  line-height: 1.75;
}
.link-cloud {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
  margin-top: 10px;
}
.link-chip {
  display: inline-flex;
  align-items: center;
  border: 1px solid #ecd7cc;
  border-radius: 999px;
  padding: 6px 12px;
  color: #5f4034;
  background: #fffaf7;
  text-decoration: none;
  font-weight: 400;
}
.link-chip:hover { color: var(--primary-red); border-color: #e84b38; }
.versions {
  display: grid;
  gap: 12px;
  align-items: stretch;
}
.version-overview .versions {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}
.version-overview {
  padding-bottom: 24px;
}
.version-card {
  display: flex;
  flex-direction: column;
  padding: 12px 14px;
  border: 1px solid #eeeeee;
  border-radius: 8px;
  background: #fff;
  min-height: 156px;
}
.version-card p {
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
  font-size: 14px;
  line-height: 1.65;
}
.version-card.primary {
  border-color: #d8d8d8;
  background: #fff;
}
.version-head {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 6px;
  font-weight: 800;
  margin-bottom: 6px;
  line-height: 1.45;
}
.version-title {
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}
.tag {
  white-space: nowrap;
  border-radius: 6px;
  padding: 3px 8px;
  background: #f5f5f5;
  color: #5f5049;
  font-size: 13px;
  font-weight: 400;
  line-height: 1.35;
}
.version-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}
.version-duration-tag {
  background: #fff;
  color: #8a2b24;
  border: 1px solid #eeeeee;
}
.version-extra {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  margin-top: 12px;
  border: 0;
  background: transparent;
}
.version-extra summary {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 7px 12px;
  border: 1px solid #eeeeee;
  border-radius: 999px;
  background: #fff;
  color: #5f5049;
  font-size: 14px;
  font-weight: 400;
  cursor: pointer;
  list-style: none;
}
.version-extra summary::-webkit-details-marker {
  display: none;
}
.version-extra-summary-open {
  display: none;
}
.version-extra[open] summary {
  order: 2;
  margin-top: 14px;
}
.version-extra[open] .version-extra-summary-closed {
  display: none;
}
.version-extra[open] .version-extra-summary-open {
  display: inline;
}
.version-extra summary::after {
  content: '+';
  color: #8f8a87;
}
.version-extra[open] summary::after {
  content: '-';
}
.version-extra .versions {
  width: 100%;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  order: 1;
  margin-top: 12px;
  padding: 0;
}
.outline-nav {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 8px;
  margin: 0 0 16px;
}
.outline-nav-link {
  display: flex;
  align-items: center;
  gap: 8px;
  min-height: 38px;
  padding: 7px 10px;
  border: 1px solid #f0ded5;
  border-radius: 8px;
  background: #fffdfb;
  color: #2c2521;
  font-size: 14px;
  line-height: 1.4;
}
.outline-nav-link span {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 30px;
  height: 24px;
  flex: 0 0 30px;
  border-radius: 999px;
  background: #fff1ea;
  color: var(--primary-red);
  font-weight: 700;
  font-size: 13px;
}
.outline-nav-link:hover {
  border-color: #e84b38;
  color: var(--primary-red);
}

.wechat-card {
  width: 265px;
  border-radius: 16px;
  overflow: visible;
  box-shadow: 0 2px 12px rgba(0, 0, 0, 0.1);
  position: relative;
}
.wechat-card-top {
  position: relative;
  border-radius: 16px 16px 0 0;
  padding: 18px 21px 0;
  height: 153px;
  overflow: hidden;
  background: #C62828;
}
.wechat-card-bg {
  position: absolute;
  top: 0;
  left: 0;
  width: 265px;
  height: 153px;
  display: block;
}
.wechat-title {
  margin: 0 0 8px;
  color: #fff;
  font-size: 20px;
  font-weight: 400;
  line-height: 1.3;
  position: relative;
  z-index: 1;
}
.wechat-tip {
  color: #fff;
  font-size: 14px;
  line-height: 1.4;
  position: relative;
  z-index: 1;
}
.wechat-qrcode-wrap {
  position: relative;
  z-index: 2;
  width: 190px;
  height: 189px;
  margin: -60px auto 0;
}
.wechat-qrcode-img {
  width: 190px;
  height: 189px;
  object-fit: cover;
  border-radius: 10px;
  display: block;
}
.wechat-card-bottom {
  background: #fff;
  border-radius: 0 0 16px 16px;
  padding: 15px 18px 18px;
  text-align: left;
}
.wechat-note {
  color: #131313;
  font-size: 14px;
  line-height: 1.5;
  text-align: center;
}
.requirement-list {
  display: grid;
  gap: 6px;
  margin: 12px 0 0;
  padding: 0;
  list-style: none;
}
.requirement-list li {
  position: relative;
  padding-left: 15px;
  color: #5f5049;
  font-size: 13px;
  line-height: 1.45;
}
.requirement-list li::before {
  content: "";
  position: absolute;
  top: 9px;
  left: 2px;
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: var(--primary-red);
}
.copy-requirement-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 100%;
  min-height: 34px;
  margin-top: 12px;
  border: 1px solid #ecd7cc;
  border-radius: 8px;
  background: #fff7f3;
  color: var(--primary-red);
  font-size: 14px;
  font-weight: 700;
  cursor: pointer;
  transition: background 0.2s ease, border-color 0.2s ease, color 0.2s ease;
}
.copy-requirement-btn.is-copied {
  border-color: #d9ead7;
  background: #f4fbf3;
  color: #277b32;
}
.copy-fallback-text {
  display: none;
  width: 100%;
  min-height: 112px;
  margin-top: 10px;
  padding: 9px 10px;
  border: 1px solid #ecd7cc;
  border-radius: 8px;
  background: #fffdfb;
  color: #5f5049;
  font-size: 13px;
  line-height: 1.55;
  resize: vertical;
}
.copy-fallback-text.is-visible {
  display: block;
}
.modal-overlay {
  display: none;
  position: fixed;
  inset: 0;
  align-items: center;
  justify-content: center;
  padding: 24px 13px;
  background: rgba(0, 0, 0, 0.5);
  z-index: 2000;
}
.modal-overlay.active {
  display: flex;
}
.modal-box {
  position: relative;
  width: 265px;
  border-radius: 16px;
  overflow: visible;
  background: #fff;
  box-shadow: 0 8px 30px rgba(0, 0, 0, 0.3);
}
.modal-close {
  position: absolute;
  top: 10px;
  right: 10px;
  z-index: 10;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 24px;
  height: 24px;
  border: 0;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.3);
  color: #fff;
  cursor: pointer;
  font-size: 12px;
  line-height: 1;
}
.modal-close:hover {
  background: rgba(255, 255, 255, 0.5);
}
.modal-top {
  position: relative;
  height: 153px;
  padding: 21px 21px 0;
  border-radius: 16px 16px 0 0;
  overflow: hidden;
  background: #C62828;
}
.modal-card-bg {
  position: absolute;
  top: 0;
  left: 0;
  display: block;
  width: 265px;
  height: 153px;
}
.modal-title {
  position: relative;
  z-index: 1;
  margin: 0 0 8px;
  color: #fff;
  font-size: 20px;
  font-weight: 400;
  line-height: 1.3;
}
.modal-tip {
  position: relative;
  z-index: 1;
  color: #fff;
  font-size: 14px;
  line-height: 1.4;
}
.modal-qrcode-wrap {
  position: relative;
  z-index: 2;
  width: 190px;
  height: 189px;
  margin: -60px auto 0;
}
.modal-qrcode-img {
  display: block;
  width: 190px;
  height: 189px;
  border-radius: 10px;
  object-fit: cover;
}
.modal-bottom {
  padding: 15px 21px 20px;
  border-radius: 0 0 16px 16px;
  background: #fff;
  text-align: left;
}
.modal-note {
  color: #131313;
  font-size: 14px;
  line-height: 1.5;
  text-align: center;
}
.mobile-fixed-btn {
  display: none;
}
.sidebar-menu {
  margin-top: 18px;
  padding: 16px 18px;
  border: 1px solid var(--warm-line);
  border-radius: 8px;
  background: #fffdfb;
}
.sidebar-menu h3 {
  margin: 0 0 12px;
  font-size: 18px;
  line-height: 1.35;
}
.sidebar-menu a {
  display: flex;
  align-items: center;
  min-height: 34px;
  padding: 0;
  border-top: 1px solid #f4e7df;
  color: #333;
  font-size: 14px;
  line-height: 1.4;
}
.sidebar-menu a:first-of-type {
  border-top: 0;
}
.sidebar-menu a:hover {
  color: var(--primary-red);
  font-weight: 700;
}
.sidebar-menu a.is-active {
  position: relative;
  color: var(--primary-red);
  font-weight: 700;
  background: #fff7f3;
  border-top-color: transparent;
  margin-left: -10px;
  margin-right: -10px;
  padding-left: 10px;
  padding-right: 10px;
  border-radius: 8px;
}
.sidebar-menu a.is-active::before {
  content: "";
  position: absolute;
  top: -1px;
  left: 10px;
  right: 10px;
  height: 1px;
  background: #f4e7df;
}
.sidebar-menu a.is-active:first-of-type::before {
  display: none;
}
.course-role-card {
  margin-top: 18px;
  padding: 16px 18px;
  border: 1px solid var(--warm-line);
  border-radius: 8px;
  background: #fffdfb;
}
.course-role-card h3 {
  margin: 0 0 6px;
  color: #211614;
  font-size: 18px;
  line-height: 1.35;
}
.course-role-card p {
  margin: 0 0 12px;
  color: #6b5b55;
  font-size: 13px;
  line-height: 1.6;
}
.course-role-card a {
  display: block;
  padding: 10px 0;
  border-top: 1px solid #f4e7df;
  color: #312522;
  font-size: 14px;
  line-height: 1.45;
}
.course-role-card a strong {
  display: block;
  margin-bottom: 2px;
  color: #211614;
  font-size: 14px;
}
.course-role-card a span {
  display: block;
  color: #806d66;
  font-size: 12px;
}
.course-role-card a:hover strong {
  color: var(--primary-red);
}
.course-teacher-card {
  display: flex;
  align-items: flex-start;
  gap: 24px;
  padding: 20px;
  border: 1px solid var(--warm-line);
  border-radius: 8px;
  background: #fffdfb;
}
.course-teacher-avatar {
  display: block;
  width: 132px;
  aspect-ratio: 1 / 1;
  padding: 2px;
  flex: 0 0 132px;
  border-radius: 18px;
  background: linear-gradient(to bottom, #ffd7c5 0%, #ffe9d1 50%, #fff3e5 100%);
  overflow: hidden;
}
.course-teacher-avatar img {
  width: 100%;
  height: 100%;
  border-radius: 16px;
  object-fit: cover;
  object-position: top center;
  background: #fff;
}
.course-teacher-body {
  min-width: 0;
  flex: 1;
}
.course-teacher-name {
  margin: 0 0 6px;
  color: var(--ink);
  font-size: 22px;
  line-height: 1.3;
  font-weight: 700;
}
.course-teacher-label {
  margin: 0 0 10px;
  color: var(--ink);
  font-weight: 400;
  font-size: 16px;
  line-height: 1.6;
}
.course-teacher-desc {
  color: #333;
}
.course-teacher-tags {
  gap: 8px;
  margin-top: 14px;
}
.course-teacher-tags .pill {
  height: 24px;
  padding: 0 12px;
  border: 1px solid rgba(255, 232, 232, 1);
  border-radius: 5px;
  background: #FFEEE5;
  color: var(--ink);
  font-size: 13px;
  line-height: 24px;
  white-space: nowrap;
}
.teacher-detail-link {
  display: inline-flex;
  align-items: center;
  margin-top: 14px;
  color: var(--primary-red);
  font-size: 15px;
  font-weight: 700;
}
.footer {
  background: #000000;
  padding: 50px 0 30px;
  margin-top: 28px;
}
.footer-content {
  max-width: var(--page-width);
  margin: 0 auto;
  padding: 0 121px;
}
.footer-intro {
  margin-bottom: 15px;
}
.footer-intro p {
  font-size: 14px;
  color: #7D7D7D;
  line-height: 1.8;
}
.footer-divider {
  width: 100%;
  height: 1px;
  background: #333333;
  margin-bottom: 20px;
}
.footer-section-block {
  margin-bottom: 20px;
}
.footer-section-title {
  font-size: 14px;
  font-weight: bold;
  color: #908F8F;
  margin: 0 0 12px;
}
.footer-tags-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0;
}
.footer-tag {
  font-size: 14px;
  color: #908F8F;
  cursor: pointer;
  transition: color 0.2s ease;
  margin-right: 30px;
  margin-bottom: 8px;
}
.footer-tag:hover {
  color: #ffffff;
}
.footer-desc {
  font-size: 13px;
  color: #908F8F;
  line-height: 1.8;
  margin-bottom: 8px;
}
.footer-bottom {
  display: flex;
  justify-content: flex-start;
  align-items: center;
  gap: 23px;
  padding-top: 20px;
  max-width: var(--page-width);
  margin: 0 auto;
  padding-left: 121px;
  padding-right: 121px;
}
.footer-bottom p {
  font-size: 14px;
  color: #7D7D7D;
  margin-bottom: 0;
}
.footer-copyright,
.footer-beian {
  text-align: left;
}
.footer-beian {
  white-space: nowrap;
}
.beian-icon {
  display: inline-block;
  width: 16px;
  height: 16px;
  vertical-align: middle;
  margin: 0 4px;
}
.breadcrumb-bottom {
  width: 100%;
  max-width: var(--content-width);
  height: 34px;
  margin-top: 40px;
  padding: 0 20px;
  display: flex;
  align-items: center;
  gap: 8px;
  overflow: hidden;
  border-radius: 10px;
  background: linear-gradient(90deg, #fff1ea 0%, rgba(245, 226, 225, 0.27) 27%, rgba(253, 230, 224, 0.36) 100%);
  color: #131313;
  font-family: "PingFang SC", "PingFangSC-Regular", sans-serif;
  font-size: 14px;
  font-weight: 400;
  box-sizing: border-box;
}
.bc-label,
.bc-link,
.bc-sep,
.bc-current {
  color: #131313;
  font-size: 14px;
  font-weight: 400;
  line-height: 1;
  white-space: nowrap;
}
.bc-link:hover {
  color: var(--primary-red);
}
.bc-current {
  min-width: 0;
  overflow: hidden;
  text-overflow: ellipsis;
}

@media (max-width: 1200px) {
  .header-nav-bar,
  .page-wrapper,
  .footer-content,
  .footer-bottom {
    padding-left: 40px;
    padding-right: 40px;
  }
  .nav-menu {
    margin-left: 40px;
  }
}

@media (max-width: 1000px) {
  .main-container {
    flex-direction: column;
  }
  .content-left,
  .sidebar-right {
    width: 100%;
  }
  .sidebar-right {
    position: static;
    display: grid;
    grid-template-columns: 265px minmax(0, 1fr);
    gap: 20px;
  }
}

@media (max-width: 820px) {
  .rich-list,
  .module-grid,
  .course-fit-grid,
  .fact-grid,
  .version-overview .versions,
  .outline-nav,
  .sidebar-right { grid-template-columns: 1fr; }
  .course-hero h1 { font-size: 30px; }
  .wechat-card {
    margin: 0 auto;
  }
}

@media (max-width: 768px) {
  .header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    width: 100%;
    padding: 0;
    margin: 0;
    box-shadow: none;
  }
  .header-top-bar {
    display: flex;
    align-items: center;
    background: #fff;
    padding: 8px 10px;
    width: 100%;
  }
  .header-nav-bar {
    max-width: 100%;
    width: 100%;
    margin: 0;
    padding: 0 13px;
    gap: 0;
  }
  .logo,
  .pc-search {
    display: none;
  }
  .nav-menu {
    width: 100%;
    justify-content: space-between;
    gap: 0;
    margin-left: 0;
  }
  .nav-link {
    font-size: 15px;
    padding: 10px 0;
  }
  .search-container {
    display: flex;
    flex: 1;
    width: 100%;
  }
  .pc-search {
    display: none;
  }
  .search-box {
    width: 100%;
    height: 44px;
    border-radius: 13px;
  }
  .search-inner {
    flex: 1;
    display: flex;
    align-items: center;
    height: 100%;
    min-width: 0;
    padding: 0 8px;
    gap: 6px;
    border-radius: 11px;
    background: #fff;
    overflow: hidden;
  }
  .mobile-logo {
    display: block;
    width: 20px;
    height: 20px;
    flex-shrink: 0;
    border-radius: 4px;
    object-fit: cover;
  }
  .search-input {
    width: auto;
    min-width: 0;
    flex: 1;
    padding: 0;
    background: transparent;
    font-size: 16px;
  }
  .search-input::placeholder {
    color: #C2BFBF;
    font-size: 16px;
  }
  .search-btn {
    flex: 0 0 68px;
    font-size: 13px;
  }
  .page-wrapper {
    padding: 0 13px;
    margin-top: 92px;
  }
  .main-container {
    padding: 24px 0 34px;
  }
  .course-hero {
    padding-top: 0;
    padding-bottom: 24px;
  }
  .course-hero h1 {
    font-size: 26px;
  }
  .course-subtitle {
    font-size: 16px;
  }
  .section {
    padding: 28px 0;
  }
  .section h2 {
    font-size: 20px;
  }
  .primary-action,
  .secondary-action {
    flex: 1;
    min-width: 0;
  }
  .course-teacher-card {
    gap: 16px;
    padding: 16px;
  }
  .course-teacher-avatar {
    width: 104px;
    aspect-ratio: 1 / 1;
    flex-basis: 104px;
    border-radius: 16px;
  }
  .course-teacher-avatar img {
    border-radius: 14px;
  }
  .course-teacher-name {
    font-size: 20px;
  }
  .breadcrumb-bottom {
    max-width: 100%;
    height: 34px;
    margin-top: 18px;
    padding: 0 9px;
    gap: 0;
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
    scrollbar-width: none;
    white-space: nowrap;
  }
  .breadcrumb-bottom::-webkit-scrollbar {
    display: none;
  }
  .bc-label,
  .bc-link,
  .bc-sep,
  .bc-current {
    font-size: 14px;
    font-weight: 400;
  }
  .bc-label,
  .bc-link,
  .bc-sep {
    margin-right: 6px;
  }
  .bc-current {
    overflow: visible;
    text-overflow: clip;
  }
  .sidebar-right {
    display: none;
  }
  .mobile-fixed-btn {
    position: fixed;
    right: 0;
    bottom: 0;
    left: 0;
    z-index: 999;
    display: flex;
    align-items: center;
    justify-content: center;
    width: 100%;
    padding: 8px 15px calc(8px + env(safe-area-inset-bottom));
    border: 0;
    background: #fff;
    cursor: pointer;
  }
  .fixed-btn-m {
    display: flex;
    align-items: center;
    justify-content: center;
    height: 31px;
    padding: 0 15px;
    border-radius: 8px;
    gap: 4px;
    background: linear-gradient(135deg, #f26a21 0%, #fb0000 100%);
  }
  .fixed-btn-text,
  .fixed-btn-link {
    color: #fff;
    font-family: "PingFangSC-Regular", "PingFang SC", sans-serif;
    font-size: 14px;
    font-weight: 400;
    line-height: 1;
    white-space: nowrap;
  }
  .mobile-fixed-btn:focus-visible .fixed-btn-m {
    outline: 2px solid rgba(173, 8, 0, 0.28);
    outline-offset: 2px;
  }
  .footer {
    margin-top: 24px;
    padding: 30px 0 calc(58px + env(safe-area-inset-bottom));
  }
  .footer-content,
  .footer-bottom {
    padding-left: 13px;
    padding-right: 13px;
  }
  .footer-section-title {
    color: #908F8F;
    font-size: 13px;
    font-weight: bold;
    margin-bottom: 10px;
  }
  .footer-tags-row {
    gap: 0;
    display: flex;
    flex-wrap: wrap;
  }
  .footer-tag {
    color: #908F8F;
    font-size: 13px;
    margin-right: 0;
    margin-bottom: 8px;
    width: 20%;
    text-align: left;
  }
  .footer-tags-hot .footer-tag {
    width: 25%;
  }
  .footer-desc {
    color: #908F8F;
    font-size: 13px;
    line-height: 1.8;
    margin-bottom: 6px;
  }
  .footer-intro p {
    color: #908F8F;
    font-size: 13px;
  }
  .footer-section-block {
    margin-bottom: 16px;
  }
  .footer-bottom {
    display: flex;
    flex-direction: column;
    align-items: center;
    padding-top: 10px;
  }
  .footer-divider {
    margin-bottom: 12px;
  }
  .footer-bottom p {
    color: #7D7D7D;
    font-size: 13px;
    margin-bottom: 4px;
    text-align: center;
  }
  .footer-copyright,
  .footer-beian {
    text-align: center;
    white-space: normal;
  }
  .beian-icon {
    margin: 0 2px;
  }
}