:root {
  --bg: #f7f3ec;
  --bg-alt: #f0e9dd;
  --card: #ffffff;
  --ink: #3a2e1f;
  --ink-light: #6b5d4d;
  --ink-faint: #9a8b78;
  --accent: #8b6f47;
  --accent-dark: #6d5635;
  --accent-light: #d4c4a8;
  --accent-bg: rgba(139, 111, 71, 0.06);
  --border: #e5ddd0;
  --gold: #c9a96e;
  --success: #5a7a5a;
  --danger: #a05050;
}
* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  font-family: 'Noto Sans SC', -apple-system, BlinkMacSystemFont, 'PingFang SC', 'Microsoft YaHei', sans-serif;
  background: var(--bg);
  color: var(--ink);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}
.container { max-width: 960px; margin: 0 auto; padding: 0 24px; }
.section { padding: 72px 0; }
.section-alt { background: var(--bg-alt); }
.section-title {
  font-family: 'Noto Serif SC', serif;
  font-size: 30px; font-weight: 700; text-align: center;
  margin-bottom: 12px; letter-spacing: 1px;
}
.section-sub {
  text-align: center; color: var(--ink-light);
  font-size: 15px; margin-bottom: 48px; max-width: 560px; margin-left: auto; margin-right: auto;
}
.tag {
  display: inline-block; font-size: 12px; letter-spacing: 3px; color: var(--accent);
  border: 1px solid var(--accent-light); padding: 5px 18px; border-radius: 20px;
  background: var(--accent-bg); font-weight: 500;
}

/* ===== 导航 ===== */
.nav {
  position: sticky; top: 0; z-index: 100;
  background: rgba(247, 243, 236, 0.92);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
}
.nav-inner {
  max-width: 960px; margin: 0 auto; padding: 14px 24px;
  display: flex; align-items: center; justify-content: space-between;
}
.nav-brand {
  font-family: 'Noto Serif SC', serif; font-size: 18px; font-weight: 700;
  color: var(--ink); letter-spacing: 1px; text-decoration: none;
}
.nav-brand span { color: var(--accent); }
.nav-links { display: flex; align-items: center; gap: 18px; }
.nav-link {
  font-size: 14px; color: var(--ink-light); text-decoration: none;
  transition: color 0.2s;
}
.nav-link:hover { color: var(--accent); }
.nav-user { font-size: 13px; color: var(--success); }
.nav-cta {
  padding: 8px 22px; background: var(--accent); color: #fff;
  border-radius: 20px; font-size: 13px; font-weight: 500;
  text-decoration: none; letter-spacing: 1px; transition: all 0.2s;
  border: none; cursor: pointer;
}
.nav-cta:hover { background: var(--accent-dark); }

/* ===== 闪消息 ===== */
.flash-area { max-width: 960px; margin: 16px auto 0; padding: 0 24px; }
.flash {
  padding: 12px 18px; border-radius: 8px; margin-bottom: 10px;
  font-size: 14px;
}
.flash-success { background: rgba(90, 122, 90, 0.12); color: var(--success); border: 1px solid rgba(90,122,90,.3); }
.flash-error { background: rgba(160, 80, 80, 0.10); color: var(--danger); border: 1px solid rgba(160,80,80,.3); }
.flash-warning { background: rgba(201,169,110,.15); color: var(--accent-dark); border: 1px solid rgba(201,169,110,.4); }

/* ===== 表单 ===== */
.auth-wrap { max-width: 420px; margin: 80px auto; }
.auth-card {
  background: var(--card); border: 1px solid var(--border);
  border-radius: 16px; padding: 40px 36px; box-shadow: 0 4px 24px rgba(58,46,31,.05);
}
.auth-card h1 {
  font-family: 'Noto Serif SC', serif; font-size: 24px; text-align: center;
  margin-bottom: 8px;
}
.auth-sub { text-align: center; color: var(--ink-light); font-size: 14px; margin-bottom: 28px; }
.form-item { margin-bottom: 18px; }
.form-item label { display: block; font-size: 13px; color: var(--ink-light); margin-bottom: 6px; }
.form-item input {
  width: 100%; padding: 12px 14px; border: 1px solid var(--border);
  border-radius: 10px; font-size: 15px; background: #fdfbf8;
  transition: border-color .2s;
}
.form-item input:focus { outline: none; border-color: var(--accent); }
.btn {
  width: 100%; padding: 13px; border: none; border-radius: 10px;
  background: var(--accent); color: #fff; font-size: 15px; font-weight: 500;
  cursor: pointer; letter-spacing: 1px; transition: background .2s;
  text-decoration: none; display: inline-block; text-align: center;
}
.btn:hover { background: var(--accent-dark); }
.btn-block { display: block; width: 100%; }
.btn-ghost {
  background: transparent; color: var(--accent); border: 1px solid var(--accent-light);
}
.btn-ghost:hover { background: var(--accent-bg); }
.btn-sm { padding: 8px 16px; font-size: 13px; border-radius: 8px; width: auto; }
.auth-switch { text-align: center; margin-top: 20px; font-size: 14px; color: var(--ink-light); }
.auth-switch a { color: var(--accent); text-decoration: none; }

/* ===== 课程中心 ===== */
.course-hero { text-align: center; padding: 64px 0 40px; }
.course-hero h1 { font-family: 'Noto Serif SC', serif; font-size: 32px; margin-bottom: 12px; }
.course-hero p { color: var(--ink-light); }
.paid-banner {
  max-width: 600px; margin: 24px auto; padding: 14px 20px;
  background: rgba(90,122,90,.10); border: 1px solid rgba(90,122,90,.3);
  border-radius: 12px; color: var(--success); font-size: 14px;
}
.unpaid-banner {
  max-width: 600px; margin: 24px auto; padding: 16px 20px;
  background: rgba(201,169,110,.12); border: 1px solid rgba(201,169,110,.4);
  border-radius: 12px; font-size: 14px; color: var(--accent-dark);
}
.unpaid-banner a { color: var(--accent-dark); font-weight: 600; }
.module-block { margin-bottom: 40px; }
.module-name {
  font-family: 'Noto Serif SC', serif; font-size: 20px;
  padding-bottom: 10px; margin-bottom: 16px;
  border-bottom: 2px solid var(--accent-light); color: var(--ink);
}
.module-name .mod-en {
  font-size: 12px; color: var(--ink-faint); letter-spacing: 2px; margin-right: 10px;
}
.course-list { display: grid; grid-template-columns: 1fr 1fr; gap: 14px; }
@media (max-width: 640px) { .course-list { grid-template-columns: 1fr; } }
.course-item {
  background: var(--card); border: 1px solid var(--border); border-radius: 12px;
  padding: 18px 20px; text-decoration: none; color: var(--ink);
  display: flex; justify-content: space-between; align-items: center; gap: 12px;
  transition: all .2s;
}
.course-item:hover { border-color: var(--accent); box-shadow: 0 4px 16px rgba(139,111,71,.10); transform: translateY(-1px); }
.course-item .ci-title { font-weight: 500; font-size: 15px; }
.course-item .ci-sub { font-size: 12px; color: var(--ink-faint); margin-top: 2px; }
.course-item .ci-meta { font-size: 12px; color: var(--accent); white-space: nowrap; }
.course-item.locked .ci-meta { color: var(--ink-faint); }

/* ===== 课程阅读页 ===== */
.reader { max-width: 780px; margin: 0 auto; padding: 48px 24px 80px; }
.reader .crumb { font-size: 13px; color: var(--ink-faint); margin-bottom: 16px; }
.reader .crumb a { color: var(--ink-faint); text-decoration: none; }
.reader .crumb a:hover { color: var(--accent); }
.reader h1 { font-family: 'Noto Serif SC', serif; font-size: 30px; margin-bottom: 8px; }
.reader .course-meta { color: var(--ink-faint); font-size: 14px; margin-bottom: 28px; padding-bottom: 20px; border-bottom: 1px solid var(--border); }
.article-body { font-size: 16px; line-height: 2; }
.article-body h2 { font-family: 'Noto Serif SC', serif; font-size: 22px; margin: 32px 0 12px; color: var(--accent-dark); }
.article-body h3 { font-size: 18px; margin: 24px 0 10px; }
.article-body p { margin-bottom: 16px; }
.article-body ul, .article-body ol { margin: 0 0 16px 24px; }
.article-body li { margin-bottom: 8px; }
.article-body code {
  background: var(--accent-bg); color: var(--accent-dark);
  padding: 2px 8px; border-radius: 6px; font-size: 14px;
}
.article-body pre {
  background: #2e2a24; color: #e8e0d4; padding: 18px; border-radius: 12px;
  overflow-x: auto; font-size: 14px; margin: 16px 0; line-height: 1.6;
}
.article-body pre code { background: none; color: inherit; padding: 0; }
.article-body img { max-width: 100%; border-radius: 12px; margin: 16px 0; }
.article-body blockquote {
  border-left: 3px solid var(--gold); background: var(--accent-bg);
  padding: 12px 18px; margin: 16px 0; color: var(--ink-light); border-radius: 0 8px 8px 0;
}
.article-body table { width: 100%; border-collapse: collapse; margin: 16px 0; font-size: 14px; }
.article-body th, .article-body td { border: 1px solid var(--border); padding: 10px 12px; text-align: left; }
.article-body th { background: var(--accent-bg); color: var(--accent-dark); }

/* 付费墙 */
.paywall {
  margin-top: 40px; padding: 36px; text-align: center;
  background: linear-gradient(180deg, var(--accent-bg), transparent);
  border: 1px dashed var(--accent-light); border-radius: 16px;
}
.paywall h3 { font-family: 'Noto Serif SC', serif; font-size: 22px; margin-bottom: 10px; color: var(--accent-dark); }
.paywall p { color: var(--ink-light); font-size: 14px; margin-bottom: 20px; }
.paywall .price { font-size: 32px; font-weight: 700; color: var(--accent-dark); margin-bottom: 20px; }
.paywall .price .cur { font-size: 18px; }
.paywall .price .old { font-size: 16px; color: var(--ink-faint); text-decoration: line-through; margin-left: 10px; font-weight: 400; }
.paywall-note { font-size: 12px; color: var(--ink-faint); margin-top: 14px; }
.pay-note { font-size: 13px; color: var(--ink-light); margin-top: 12px; line-height: 1.8; }

/* 上下课 */
.course-nav { display: flex; justify-content: space-between; gap: 16px; margin-top: 48px; padding-top: 24px; border-top: 1px solid var(--border); }
.course-nav a {
  text-decoration: none; color: var(--accent); font-size: 14px;
  padding: 10px 18px; border: 1px solid var(--accent-light); border-radius: 10px;
  transition: all .2s; max-width: 46%;
}
.course-nav a:hover { background: var(--accent-bg); }
.course-nav .cn-label { display: block; font-size: 12px; color: var(--ink-faint); }
.course-nav .next { text-align: right; }

/* ===== 管理后台 ===== */
.admin-wrap { max-width: 980px; margin: 0 auto; padding: 48px 24px 80px; }
.admin-wrap h1 { font-family: 'Noto Serif SC', serif; font-size: 28px; margin-bottom: 8px; }
.admin-stats { display: flex; gap: 16px; margin: 24px 0; }
.stat-card {
  background: var(--card); border: 1px solid var(--border); border-radius: 12px;
  padding: 18px 24px; flex: 1;
}
.stat-card .num { font-size: 28px; font-weight: 700; color: var(--accent-dark); }
.stat-card .label { font-size: 13px; color: var(--ink-faint); }
.admin-table { width: 100%; border-collapse: collapse; background: var(--card); border-radius: 12px; overflow: hidden; }
.admin-table th, .admin-table td { padding: 12px 14px; border-bottom: 1px solid var(--border); text-align: left; font-size: 14px; }
.admin-table th { background: var(--bg-alt); font-weight: 600; }
.admin-table .paid-yes { color: var(--success); font-weight: 600; }
.admin-table .paid-no { color: var(--ink-faint); }
.admin-actions { display: flex; gap: 8px; align-items: center; flex-wrap: wrap; }
.remark-form { display: flex; gap: 6px; }
.remark-form input {
  padding: 6px 10px; border: 1px solid var(--border); border-radius: 8px;
  font-size: 12px; width: 140px; background: #fdfbf8;
}
.btn-danger { background: transparent; color: var(--danger); border: 1px solid rgba(160,80,80,.4); }
.btn-danger:hover { background: rgba(160,80,80,.08); }
.btn-success { background: var(--success); }
.btn-success:hover { background: #4a6a4a; }

/* ===== 营销页：Hero ===== */
.hero {
  padding: 80px 0 64px; text-align: center;
  background: linear-gradient(180deg, var(--bg-alt) 0%, var(--bg) 100%);
  position: relative; overflow: hidden;
}
.hero h1 {
  font-family: 'Noto Serif SC', serif;
  font-size: 42px; font-weight: 900; line-height: 1.3;
  margin: 0 0 20px; letter-spacing: 2px;
}
.hero h1 .highlight { color: var(--accent); }
.hero .subtitle { font-size: 17px; color: var(--ink-light); line-height: 1.9; margin: 0 auto 36px; max-width: 560px; }
.hero-meta { display: flex; justify-content: center; gap: 40px; flex-wrap: wrap; margin-bottom: 28px; }
.hero-meta-item .num { font-family: 'Noto Serif SC', serif; font-size: 34px; font-weight: 700; color: var(--accent-dark); }
.hero-meta-item .lbl { font-size: 13px; color: var(--ink-faint); letter-spacing: 1px; }
.hero-price { margin-bottom: 28px; }
.hero-price .price-new { font-size: 36px; font-weight: 700; color: var(--accent-dark); }
.hero-price .price-old { font-size: 20px; color: var(--ink-faint); text-decoration: line-through; margin-left: 10px; }
.hero-price .price-tag { display: block; font-size: 13px; color: var(--gold); margin-top: 6px; letter-spacing: 1px; }

/* ===== 营销页：通用卡片 ===== */
.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 18px; }
.grid-4 { display: grid; grid-template-columns: repeat(4, 1fr); gap: 18px; }
@media (max-width: 768px) { .grid-3, .grid-4 { grid-template-columns: 1fr 1fr; } }
@media (max-width: 480px) { .grid-3, .grid-4 { grid-template-columns: 1fr; } }
.card {
  background: var(--card); border: 1px solid var(--border); border-radius: 14px;
  padding: 26px 24px; transition: all .25s;
}
.card:hover { box-shadow: 0 6px 24px rgba(58,46,31,.07); transform: translateY(-2px); }
.card h3 { font-size: 16px; margin-bottom: 8px; color: var(--accent-dark); }
.card p { font-size: 14px; color: var(--ink-light); }
.card-num .card-num { font-family: 'Noto Serif SC', serif; font-size: 28px; color: var(--gold); margin-bottom: 6px; }

/* ===== 营销页：课程大纲 ===== */
.curriculum { max-width: 760px; margin: 0 auto; }
.cur-block { margin-bottom: 28px; }
.cur-mod {
  font-family: 'Noto Serif SC', serif; font-size: 19px; font-weight: 700;
  color: var(--accent-dark); margin-bottom: 12px; letter-spacing: 1px;
}
.cur-en { font-size: 12px; color: var(--ink-faint); letter-spacing: 2px; margin-right: 10px; }
.cur-lessons { border: 1px solid var(--border); border-radius: 12px; overflow: hidden; background: var(--card); }
.cur-lesson {
  display: flex; align-items: center; gap: 12px; padding: 13px 18px;
  border-bottom: 1px solid var(--border); font-size: 14px;
}
.cur-lesson:last-child { border-bottom: none; }
.cl-no { color: var(--accent); font-size: 12px; white-space: nowrap; }
.cl-title { flex: 1; }
.cl-time { color: var(--ink-faint); font-size: 12px; white-space: nowrap; }
.cur-bonus {
  margin-top: 32px; padding: 28px; text-align: center;
  background: linear-gradient(135deg, rgba(201,169,110,.12), rgba(139,111,71,.06));
  border: 1px dashed var(--gold); border-radius: 14px;
}
.cur-bonus h3 { font-family: 'Noto Serif SC', serif; font-size: 18px; margin-bottom: 8px; }
.cur-bonus p { font-size: 14px; color: var(--ink-light); }

/* ===== 营销页：讲师 ===== */
.teacher-card {
  display: flex; gap: 28px; align-items: flex-start;
  max-width: 680px; margin: 0 auto; background: var(--card);
  border: 1px solid var(--border); border-radius: 16px; padding: 32px;
}
.teacher-avatar {
  width: 96px; height: 96px; flex-shrink: 0; border-radius: 50%;
  background: var(--accent-bg); border: 2px solid var(--gold);
  display: flex; align-items: center; justify-content: center;
  font-family: 'Noto Serif SC', serif; font-size: 40px; font-weight: 700; color: var(--accent);
}
.teacher-info h3 { font-family: 'Noto Serif SC', serif; font-size: 22px; margin-bottom: 4px; }
.teacher-role { color: var(--accent); font-size: 13px; margin-bottom: 12px; }
.teacher-info p { font-size: 14px; color: var(--ink-light); margin-bottom: 10px; }
.teacher-tags { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 12px; }
.teacher-tags span {
  font-size: 12px; padding: 4px 12px; border-radius: 20px;
  background: var(--accent-bg); color: var(--accent-dark); border: 1px solid var(--accent-light);
}
@media (max-width: 560px) { .teacher-card { flex-direction: column; align-items: center; text-align: center; } }

/* ===== 营销页：定价 ===== */
.pricing-grid { display: flex; gap: 24px; justify-content: center; align-items: stretch; flex-wrap: wrap; }
.pricing-card {
  flex: 1; min-width: 300px; max-width: 480px; text-align: center;
  background: var(--card); border: 2px solid var(--gold); border-radius: 18px;
  padding: 40px 36px; box-shadow: 0 8px 32px rgba(58,46,31,.08);
}
.pricing-card-hot { border: 2px solid var(--accent); position: relative; }
.pricing-card h2 { font-family: 'Noto Serif SC', serif; font-size: 26px; margin-bottom: 6px; }
.pricing-sub { color: var(--ink-light); font-size: 14px; margin-bottom: 18px; }
.pricing-price { margin: 16px 0 8px; }
.pricing-price .price-new { font-size: 44px; font-weight: 700; color: var(--accent-dark); }
.pricing-price .price-old { font-size: 22px; color: var(--ink-faint); text-decoration: line-through; margin-left: 12px; }
.pricing-valid { font-size: 13px; color: var(--ink-faint); margin-bottom: 20px; }
.pricing-list { list-style: none; text-align: left; max-width: 320px; margin: 0 auto; }
.pricing-list li { padding: 8px 0; font-size: 14px; border-bottom: 1px dashed var(--border); }
.pricing-list li:before { content: '✓ '; color: var(--success); font-weight: 700; }
.pricing-note { font-size: 12px; color: var(--ink-faint); margin-top: 14px; }

/* ===== 营销页：FAQ ===== */
.faq-list { max-width: 680px; margin: 0 auto; }
.faq-item {
  background: var(--card); border: 1px solid var(--border); border-radius: 12px;
  padding: 20px 24px; margin-bottom: 14px;
}
.faq-item h3 { font-size: 15px; color: var(--accent-dark); margin-bottom: 6px; }
.faq-item p { font-size: 14px; color: var(--ink-light); }

/* ===== 营销页：CTA ===== */
.cta-line { font-size: 16px; color: var(--accent-dark); font-weight: 500; }

/* ===== 页脚 ===== */
.footer { border-top: 1px solid var(--border); padding: 40px 0; text-align: center; color: var(--ink-faint); font-size: 13px; }
.footer-small { margin-top: 6px; font-size: 12px; }

/* 简单响应式 */
@media (max-width: 640px) {
  .section { padding: 48px 0; }
  .course-nav { flex-direction: column; }
  .course-nav a { max-width: 100%; }
}