/* ============================================================
   梯子外贸实训学院 · 全站共享样式表 style.css
   主题：蓝金配色 / 椭顿柔和圆角 / 现代 B 端商务风格
   本文件被 index / about / course / teacher / contact 5 个页面共用，
   改配色、圆角、间距只需动这一份，全站同步。
   ============================================================ */

/* ---------- 1. 设计变量（配色 / 圆角 / 阴影 / 字体） ---------- */
:root {
  /* 主色：高级深蓝 */
  --blue-900: #0B2B5B;
  --blue-800: #123A73;
  --blue-700: #1B4B96;
  --blue-600: #2361A8;
  --blue-100: #E3EDF9;
  --blue-50:  #F0F5FC;

  /* 辅助色：鎏金 / 浅金 */
  --gold-600: #A9811F;
  --gold-500: #C9A227;
  --gold-400: #D7B54A;
  --gold-300: #E3C96E;
  --gold-100: #F6EDD5;
  --gold-50:  #FBF6E9;

  /* 中性色：背景 / 文字 */
  --ink:    #16263D;   /* 深灰黑，标题 */
  --text:   #41516B;   /* 正文 */
  --muted:  #7F8CA0;   /* 次要文字 */
  --line:   #E7EBF2;   /* 分割线 / 描边 */
  --bg:     #FFFFFF;   /* 主背景 */
  --bg-soft:#F4F6FA;   /* 浅灰背景区 */

  /* 渐变（蓝金主题） */
  --grad-blue: linear-gradient(135deg, #0B2B5B 0%, #123A73 45%, #2361A8 78%, #2E79C2 100%);
  --grad-hero: linear-gradient(135deg, #0B2B5B 0%, #123A73 42%, #1B4B96 74%, #2E79C2 110%);
  --grad-gold: linear-gradient(135deg, #C9A227 0%, #D7B54A 100%);

  /* 椭顿柔和圆角（全站大圆角，拒绝尖锐直角） */
  --radius-sm:  12px;
  --radius-md:  18px;
  --radius-lg:  24px;
  --radius-xl:  34px;
  --radius-pill:999px;

  /* 柔和阴影 */
  --shadow-sm: 0 2px 10px rgba(11, 43, 91, .06);
  --shadow-md: 0 12px 30px rgba(11, 43, 91, .10);
  --shadow-lg: 0 20px 50px rgba(11, 43, 91, .14);

  /* 商用无衬线现代字体栈（系统自带，无需外链，规避版权风险） */
  --font-sans: "PingFang SC", "Microsoft YaHei", "Noto Sans SC", "Source Han Sans SC",
               "Hiragino Sans GB", system-ui, -apple-system, "Segoe UI", Roboto,
               "Helvetica Neue", Arial, sans-serif;
}

/* ---------- 2. 基础重置 ---------- */
* { margin: 0; padding: 0; box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  font-family: var(--font-sans);
  color: var(--text);
  background: var(--bg);
  line-height: 1.7;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
}

img { max-width: 100%; display: block; }
a { text-decoration: none; color: inherit; }
ul, ol { list-style: none; }

h1, h2, h3, h4 {
  color: var(--ink);
  font-weight: 800;
  line-height: 1.3;
  letter-spacing: .01em;
}

::selection { background: var(--gold-300); color: var(--blue-900); }

/* 键盘聚焦可见（无障碍） */
:focus-visible { outline: 3px solid var(--gold-500); outline-offset: 2px; border-radius: 6px; }

/* ---------- 3. 布局容器 ---------- */
.container {
  width: 100%;
  max-width: 1180px;
  margin: 0 auto;
  padding: 0 24px;
}

.section { padding: 84px 0; }
.section--soft { background: var(--bg-soft); }
.section--grad  { background: linear-gradient(180deg, var(--blue-50), var(--bg)); }

/* 版块标题（每节统一的标题区） */
.section-head { max-width: 720px; margin: 0 auto 48px; text-align: center; }
.section-head--left { margin-left: 0; text-align: left; }

/* 小标签：金色胶囊眉题，如「核心课程」「导师天团」 */
.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 16px;
  border-radius: var(--radius-pill);
  background: var(--gold-100);
  color: var(--gold-600);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: .06em;
  margin-bottom: 16px;
}
.eyebrow::before {
  content: "";
  width: 7px; height: 7px;
  border-radius: 50%;
  background: var(--grad-gold);
}
.eyebrow--blue { background: var(--blue-100); color: var(--blue-700); }
.eyebrow--blue::before { background: var(--grad-blue); }

.section-title { font-size: 34px; font-weight: 800; }
.section-title .gold { color: var(--gold-500); }            /* 标题里金色的强调词 */
.section-title .blue { color: var(--blue-700); }
.section-sub { margin-top: 14px; color: var(--muted); font-size: 16px; }

/* ---------- 4. 按钮（全部大圆角胶囊） ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 13px 28px;
  border-radius: var(--radius-pill);
  border: 2px solid transparent;
  font-family: var(--font-sans);
  font-size: 15px;
  font-weight: 700;
  cursor: pointer;
  transition: transform .25s ease, box-shadow .25s ease, background .25s ease, color .25s ease;
  white-space: nowrap;
}
.btn:hover { transform: translateY(-2px); }
.btn:active { transform: translateY(0); }

.btn-lg  { padding: 16px 36px; font-size: 16px; }
.btn-sm  { padding: 9px 20px;  font-size: 14px; }

/* 主按钮：深蓝 */
.btn-primary { background: var(--grad-blue); color: #fff; box-shadow: 0 8px 20px rgba(11,43,91,.25); }
.btn-primary:hover { box-shadow: 0 12px 28px rgba(11,43,91,.32); }

/* 强调按钮：鎏金 */
.btn-gold { background: var(--grad-gold); color: var(--blue-900); box-shadow: 0 8px 20px rgba(201,162,39,.32); }
.btn-gold:hover { box-shadow: 0 12px 28px rgba(201,162,39,.42); }

/* 描边按钮：白色（用在深蓝 banner 上） */
.btn-ghost { border-color: rgba(255,255,255,.55); color: #fff; background: rgba(255,255,255,.08); }
.btn-ghost:hover { background: rgba(255,255,255,.16); }

/* 文字箭头链接，如「了解更多 →」 */
.btn-more {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  color: var(--blue-700);
  font-weight: 700;
  font-size: 14px;
  transition: gap .25s ease, color .25s ease;
}
.btn-more::after { content: "→"; transition: transform .25s ease; }
.btn-more:hover { color: var(--gold-600); gap: 10px; }

/* ============================================================
   5. 全局导航栏（5 页共用，改一处全站同步）
   ============================================================ */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255, 255, 255, .92);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--line);
  transition: box-shadow .3s ease;
}
.site-header.scrolled { box-shadow: var(--shadow-sm); }

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  height: 76px;
}

/* Logo：图片 + 文字 */
.logo { display: inline-flex; align-items: center; gap: 12px; flex-shrink: 0; }
.logo-img { width: 44px; height: 44px; border-radius: 14px; object-fit: contain; background: #fff; }
.logo-text { font-size: 18px; font-weight: 800; color: var(--blue-900); letter-spacing: .02em; }
.logo-text em { font-style: normal; color: var(--gold-500); }

/* 主导航 */
.main-nav { display: flex; gap: 4px; }
.main-nav a {
  position: relative;
  padding: 9px 18px;
  border-radius: var(--radius-pill);
  font-size: 15px;
  font-weight: 600;
  color: var(--text);
  transition: color .25s ease, background .25s ease;
}
.main-nav a:hover { color: var(--blue-800); background: var(--blue-50); }
/* 当前页高亮：金色胶囊 */
.main-nav a.active { background: var(--grad-gold); color: var(--blue-900); font-weight: 700; }

.header-actions { display: flex; align-items: center; gap: 14px; }

/* 移动端汉堡按钮 */
.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 44px; height: 44px;
  border: none;
  background: var(--blue-50);
  border-radius: 12px;
  cursor: pointer;
  padding: 10px;
}
.nav-toggle span { display: block; height: 2px; border-radius: 2px; background: var(--blue-800); transition: transform .3s ease, opacity .3s ease; }
.nav-toggle.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-toggle.open span:nth-child(2) { opacity: 0; }
.nav-toggle.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ============================================================
   6. 页脚（5 页共用）
   ============================================================ */
.site-footer { background: var(--grad-blue); color: #c6d3e8; margin-top: 0; }
.footer-grid {
  display: grid;
  grid-template-columns: 1.6fr 1.2fr;
  gap: 44px;
  padding: 64px 0 48px;
}
.footer-brand .logo-text { color: #fff; }
.footer-brand .logo-text em { color: var(--gold-400); }
.footer-brand p { margin: 16px 0 20px; font-size: 14px; color: #aebfda; }
.footer-col h4 { color: #fff; font-size: 16px; margin-bottom: 18px; }
.footer-col h4::after { content: ""; display: block; width: 26px; height: 3px; border-radius: 3px; background: var(--grad-gold); margin-top: 8px; }
.footer-col ul li { margin-bottom: 11px; }
.footer-col a { font-size: 14px; color: #c6d3e8; transition: color .25s ease, padding-left .25s ease; }
.footer-col a:hover { color: var(--gold-400); padding-left: 4px; }

.footer-contact li { display: flex; gap: 10px; align-items: flex-start; font-size: 14px; color: #c6d3e8; margin-bottom: 12px; }
.footer-contact .ico { width: 22px; flex-shrink: 0; text-align: center; color: var(--gold-400); }

.footer-bottom { border-top: 1px solid rgba(255,255,255,.12); padding: 18px 0; }
.footer-bottom .container { display: flex; justify-content: space-between; gap: 12px; flex-wrap: wrap; font-size: 13px; color: #9db1d0; }

/* ============================================================
   7. 页面顶部 Hero 区
   首页大 banner 与内页小 banner 共用一套圆角渐变容器
   ============================================================ */
.hero {
  padding: 34px 0 30px;
  background: var(--bg-soft);
  background-image: radial-gradient(circle at 8% 10%, rgba(201,162,39,.10), transparent 42%),
                    radial-gradient(circle at 96% 92%, rgba(18,58,115,.10), transparent 46%);
}

/* 圆角渐变 Banner 容器（椭顿大圆角） */
.hero-card {
  position: relative;
  overflow: hidden;
  border-radius: var(--radius-xl);
  background: var(--grad-hero);
  color: #eaf0fa;
  padding: 72px 60px;
  box-shadow: var(--shadow-lg);
}

/* 柔和的椭圆光斑装饰，营造“椭顿感” */
.hero-card::before, .hero-card::after {
  content: "";
  position: absolute;
  border-radius: 50%;
  pointer-events: none;
}
.hero-card::before {
  width: 460px; height: 460px;
  top: -160px; right: -120px;
  background: radial-gradient(circle, rgba(201,162,39,.40), rgba(201,162,39,0) 70%);
}
.hero-card::after {
  width: 380px; height: 380px;
  bottom: -170px; left: -100px;
  background: radial-gradient(circle, rgba(255,255,255,.10), rgba(255,255,255,0) 70%);
}
.hero-card .hero-ring {
  position: absolute;
  right: 40px; bottom: 30px;
  width: 180px; height: 180px;
  border-radius: 50%;
  border: 2px dashed rgba(201,162,39,.45);
  opacity: .7;
  pointer-events: none;
}

.hero-inner { position: relative; z-index: 2; max-width: 680px; }
.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 7px 18px;
  border-radius: var(--radius-pill);
  background: rgba(255,255,255,.12);
  border: 1px solid rgba(201,162,39,.5);
  color: var(--gold-300);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: .05em;
  margin-bottom: 22px;
}
.hero-title { color: #fff; font-size: 46px; line-height: 1.25; }
.hero-title .gold { color: var(--gold-400); }
.hero-sub { margin: 20px 0 32px; font-size: 17px; color: #d5e0f2; max-width: 600px; }
.hero-actions { display: flex; gap: 14px; flex-wrap: wrap; }

/* 首页 hero 数据条：千万战神 / 实战体系等 */
.hero-stats {
  position: relative;
  z-index: 2;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
  margin-top: 34px;
  padding-top: 30px;
  border-top: 1px solid rgba(255,255,255,.14);
}
.hero-stat b { display: block; font-size: 28px; color: #fff; font-weight: 800; }
.hero-stat b i { font-style: normal; color: var(--gold-400); }
.hero-stat span { font-size: 13px; color: #b9c9e4; }

/* 内页 banner：标题更小 + 面包屑 */
.hero-card--page { padding: 58px 56px; }
.page-breadcrumb { font-size: 13px; color: #b9c9e4; margin-bottom: 14px; letter-spacing: .03em; }
.page-breadcrumb a { color: var(--gold-300); }
.page-breadcrumb a:hover { color: #fff; }
.hero-card--page .hero-title { font-size: 38px; }

/* ============================================================
   8. 通用卡片（圆角 + 柔和阴影 + 轻 hover 浮起）
   ============================================================ */
.card {
  background: #fff;
  border-radius: var(--radius-lg);
  border: 1px solid var(--line);
  box-shadow: var(--shadow-sm);
  transition: transform .3s ease, box-shadow .3s ease, border-color .3s ease;
}
.card:hover { transform: translateY(-4px); box-shadow: var(--shadow-md); border-color: rgba(201,162,39,.35); }

/* 价值卡片：首页核心价值 / 关于页特色 */
.value-card { padding: 30px 26px; }
.value-icon {
  width: 56px; height: 56px;
  border-radius: 18px;
  display: flex; align-items: center; justify-content: center;
  font-size: 26px;
  margin-bottom: 18px;
  background: var(--blue-50);
}
.value-card:nth-child(odd) .value-icon { background: var(--gold-100); }
.value-card h3 { font-size: 19px; margin-bottom: 10px; }
.value-card p { font-size: 14px; color: var(--muted); }

/* 三列 / 四列自适应网格 */
.grid-4 { display: grid; grid-template-columns: repeat(4, 1fr); gap: 22px; }
.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
.grid-2 { display: grid; grid-template-columns: repeat(2, 1fr); gap: 26px; }

/* ============================================================
   9. 课程卡片（course 页 + 首页预览）
   ============================================================ */
.course-card { display: flex; flex-direction: column; padding: 28px 26px; }
.course-num {
  font-size: 14px; font-weight: 800; letter-spacing: .06em;
  color: var(--gold-600);
  background: var(--gold-100);
  border-radius: var(--radius-pill);
  padding: 4px 12px;
  align-self: flex-start;
  margin-bottom: 16px;
}
.course-card h3 { font-size: 20px; margin-bottom: 8px; }
.course-card .course-sub { font-size: 14px; color: var(--blue-700); font-weight: 700; margin-bottom: 12px; }
.course-card p { font-size: 14px; color: var(--muted); flex: 1; }
.course-tags { display: flex; flex-wrap: wrap; gap: 8px; margin: 16px 0 18px; }
.chip {
  padding: 4px 12px;
  border-radius: var(--radius-pill);
  background: var(--blue-50);
  color: var(--blue-700);
  font-size: 12px;
  font-weight: 600;
}

/* ============================================================
   10. 讲师卡片（teacher 页 + 首页预览）
   ============================================================ */
.teacher-card { overflow: hidden; }
/* 讲师照片占位框：大尺寸、圆角、椭顿造型。
   内部放了一张 <img>，当 assets/images/teachers/xxx.jpg 存在时自动显示真实照片；
   不存在时显示渐变占位 + 人形图标，方便后续替换。 */
.teacher-photo {
  position: relative;
  aspect-ratio: 9 / 16;
  border-radius: var(--radius-lg);
  overflow: hidden;
  margin: 12px 12px 0;
  background: linear-gradient(160deg, var(--blue-100), var(--blue-50) 45%, var(--gold-100));
}
.teacher-photo img { position: absolute; inset: 0; width: 100%; height: 100%; object-fit: cover; z-index: 2; }
.photo-placeholder {
  position: absolute; inset: 0; z-index: 1;
  display: flex; flex-direction: column; align-items: center; justify-content: center; gap: 10px;
  color: var(--blue-700);
  font-size: 13px; font-weight: 700; letter-spacing: .08em;
}
.photo-placeholder .person-ico {
  width: 72px; height: 72px; border-radius: 50%;
  display: flex; align-items: center; justify-content: center;
  background: rgba(255,255,255,.7);
  box-shadow: 0 6px 16px rgba(18,58,115,.10);
  color: var(--gold-500);
}
.teacher-body { padding: 20px 24px 26px; }
.teacher-name { font-size: 18px; font-weight: 800; display: flex; align-items: center; gap: 10px; }
.teacher-tag {
  font-size: 11px; font-weight: 700; letter-spacing: .04em;
  color: var(--gold-600);
  background: var(--grad-gold);
  -webkit-background-clip: text;
  background-clip: text;
}
.teacher-role { font-size: 13px; color: var(--blue-700); font-weight: 600; margin: 4px 0 10px; }
.teacher-bio { font-size: 13px; color: var(--muted); }

/* ============================================================
   11. 首页专用板块
   ============================================================ */
/* Slogan 带 */
.slogan-band { background: var(--grad-blue); border-radius: var(--radius-xl); padding: 40px 48px; margin-top: -42px; position: relative; z-index: 3; box-shadow: var(--shadow-lg); }
.slogan-band { display: flex; align-items: center; justify-content: space-between; gap: 30px; flex-wrap: wrap; }
.slogan-band h2 { color: #fff; font-size: 30px; }
.slogan-band h2 em { font-style: normal; color: var(--gold-400); }
.slogan-band p { color: #c6d3e8; margin-top: 8px; font-size: 15px; }

/* CTA 引导带（首页底部 / 各页通用） */
.cta-band { background: var(--grad-blue); border-radius: var(--radius-xl); padding: 56px 48px; text-align: center; position: relative; overflow: hidden; }
.cta-band::before { content: ""; position: absolute; width: 320px; height: 320px; border-radius: 50%; background: radial-gradient(circle, rgba(201,162,39,.32), transparent 70%); top: -120px; left: -80px; }
.cta-band::after  { content: ""; position: absolute; width: 260px; height: 260px; border-radius: 50%; background: radial-gradient(circle, rgba(255,255,255,.08), transparent 70%); bottom: -110px; right: -60px; }
.cta-band h2 { color: #fff; font-size: 32px; position: relative; z-index: 2; }
.cta-band h2 em { font-style: normal; color: var(--gold-400); }
.cta-band p { color: #c6d3e8; margin: 12px auto 28px; max-width: 560px; position: relative; z-index: 2; }
.cta-band .btn { position: relative; z-index: 2; }

/* ============================================================
   12. 关于页板块
   ============================================================ */
.about-feature { padding: 30px 28px; }
.about-feature h3 { font-size: 20px; margin-bottom: 12px; display: flex; align-items: center; gap: 10px; }
.about-feature .f-num {
  font-size: 13px; font-weight: 800; color: #fff;
  background: var(--grad-gold); border-radius: 50%;
  width: 26px; height: 26px; display: inline-flex; align-items: center; justify-content: center;
  flex-shrink: 0;
}
.about-feature p { font-size: 14px; color: var(--muted); }
.about-feature ul { margin-top: 14px; }
.about-feature li { font-size: 14px; color: var(--text); padding-left: 22px; position: relative; margin-bottom: 8px; }
.about-feature li::before { content: "◆"; position: absolute; left: 0; color: var(--gold-500); font-size: 10px; top: 3px; }

/* 使命愿景大卡片 */
.mission-card {
  border-radius: var(--radius-xl);
  background: var(--grad-hero);
  color: #eaf0fa;
  padding: 48px;
  position: relative; overflow: hidden;
}
.mission-card::before { content: ""; position: absolute; width: 300px; height: 300px; border-radius: 50%; background: radial-gradient(circle, rgba(201,162,39,.35), transparent 70%); top: -120px; right: -80px; }
.mission-card h3 { color: #fff; font-size: 24px; margin-bottom: 16px; }
.mission-card h3 em { font-style: normal; color: var(--gold-400); }
.mission-card p { color: #d5e0f2; margin-bottom: 14px; font-size: 15px; }
.mission-card .quote { font-size: 20px; font-weight: 700; color: var(--gold-300); margin-top: 20px; position: relative; z-index: 2; }

/* ============================================================
   13. 联系页表单
   ============================================================ */
.contact-wrap { display: grid; grid-template-columns: 1.25fr 1fr; gap: 30px; align-items: start; }

.form-card { padding: 40px; }
.form-row { margin-bottom: 20px; }
.form-row label { display: block; font-size: 14px; font-weight: 700; color: var(--ink); margin-bottom: 8px; }
.form-row label i { font-style: normal; color: var(--gold-600); }
.form-input, .form-textarea {
  width: 100%;
  font-family: var(--font-sans);
  font-size: 15px;
  color: var(--ink);
  padding: 13px 16px;
  border: 2px solid var(--line);
  border-radius: var(--radius-md);
  background: var(--bg);
  transition: border-color .25s ease, box-shadow .25s ease;
}
.form-input:focus, .form-textarea:focus {
  outline: none;
  border-color: var(--gold-500);
  box-shadow: 0 0 0 4px rgba(201,162,39,.14);
}
.form-textarea { min-height: 140px; resize: vertical; }
.form-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 18px; }
.form-hint { font-size: 12px; color: var(--muted); margin-top: 14px; }

/* 联系信息卡片 */
.contact-info-card { padding: 40px; background: var(--grad-blue); border-radius: var(--radius-lg); color: #eaf0fa; }
.contact-info-card h3 { color: #fff; font-size: 22px; margin-bottom: 22px; }
.contact-info-card ul li { display: flex; gap: 14px; margin-bottom: 20px; align-items: flex-start; }
.contact-info-card .ico {
  width: 40px; height: 40px; flex-shrink: 0;
  border-radius: 12px;
  background: rgba(201,162,39,.18);
  display: flex; align-items: center; justify-content: center;
  font-size: 18px;
}
.contact-info-card b { display: block; font-size: 14px; color: #fff; margin-bottom: 2px; }
.contact-info-card span { font-size: 13px; color: #c6d3e8; word-break: break-all; }
.contact-info-card .work-time { font-size: 12px; color: #9db1d0; margin-top: 8px; }

/* 表单提交成功提示 */
.form-success {
  display: none;
  text-align: center;
  padding: 40px 20px;
  color: var(--blue-800);
}
.form-success .ok { font-size: 48px; display: block; margin-bottom: 12px; }
.form-success b { font-size: 20px; display: block; margin-bottom: 8px; color: var(--ink); }
.form-success p { color: var(--muted); font-size: 14px; }

/* ============================================================
   14. 简单动效
   ============================================================ */
.reveal { opacity: 0; transform: translateY(14px); transition: opacity .6s ease, transform .6s ease; }
.reveal.in { opacity: 1; transform: none; }
@media (prefers-reduced-motion: reduce) {
  .reveal { opacity: 1; transform: none; transition: none; }
}

/* ============================================================
   15. 响应式
   ============================================================ */
@media (max-width: 1024px) {
  .grid-4 { grid-template-columns: repeat(2, 1fr); }
  .footer-grid { grid-template-columns: 1fr 1fr; }
  .hero-stats { grid-template-columns: repeat(2, 1fr); }
  .hero-card { padding: 56px 44px; }
  .hero-title { font-size: 38px; }
}

@media (max-width: 900px) {
  .main-nav {
    position: fixed;
    top: 76px; left: 0; right: 0;
    flex-direction: column;
    gap: 6px;
    padding: 18px 24px 24px;
    background: #fff;
    border-bottom: 1px solid var(--line);
    box-shadow: var(--shadow-md);
    transform: translateY(-120%);
    transition: transform .3s ease;
    z-index: 99;
  }
  .main-nav.open { transform: translateY(0); }
  .main-nav a { padding: 13px 18px; font-size: 16px; }
  .nav-toggle { display: flex; }
  .header-cta { display: none; }
  .grid-3 { grid-template-columns: repeat(2, 1fr); }
  .contact-wrap { grid-template-columns: 1fr; }
}

@media (max-width: 640px) {
  .section { padding: 56px 0; }
  .section-title { font-size: 27px; }
  .hero-card { padding: 44px 26px; border-radius: var(--radius-lg); }
  .hero-card--page { padding: 40px 26px; }
  .hero-title { font-size: 30px; }
  .hero-sub { font-size: 15px; }
  .grid-4, .grid-3, .grid-2 { grid-template-columns: 1fr; }
  .hero-stats { grid-template-columns: 1fr 1fr; gap: 14px; }
  .footer-grid { grid-template-columns: 1fr; gap: 30px; }
  .cta-band { padding: 40px 26px; }
  .form-grid { grid-template-columns: 1fr; }
  .form-card, .contact-info-card { padding: 28px 22px; }
  .slogan-band { padding: 30px 26px; margin-top: -30px; }
  .slogan-band h2 { font-size: 24px; }
}

/* ============================================================
   16. 滚动照片墙（首页课程掠影 / 关于页团队风采）
   图片横向自动滚动，悬停暂停，两端渐变淡出
   ============================================================ */
.photo-scroll {
  overflow: hidden;
  padding: 8px 0;
  -webkit-mask-image: linear-gradient(90deg, transparent, #000 6%, #000 94%, transparent);
  mask-image: linear-gradient(90deg, transparent, #000 6%, #000 94%, transparent);
}
.photo-scroll-track {
  display: flex;
  gap: 18px;
  width: max-content;
  animation: photoScroll 42s linear infinite;
}
.photo-scroll:hover .photo-scroll-track { animation-play-state: paused; }
.photo-scroll-track img {
  height: 240px;
  width: auto;
  max-width: none;
  object-fit: cover;
  border-radius: var(--radius-md);
  box-shadow: 0 8px 24px rgba(11, 43, 91, .12);
  flex-shrink: 0;
}
@keyframes photoScroll {
  from { transform: translateX(0); }
  to   { transform: translateX(-50%); }
}
@media (max-width: 640px) {
  .photo-scroll-track img { height: 170px; }
}

/* ============================================================
   17. 课程页宣传视频
   ============================================================ */
.video-wrap {
  max-width: 860px;
  margin: 0 auto;
}
.video-frame {
  width: 100%;
  aspect-ratio: 16 / 9;
  background: #000;
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: 0 18px 44px rgba(11, 43, 91, .16);
  border: 1px solid rgba(201, 162, 39, .25);
}
.video-frame video {
  width: 100%;
  height: 100%;
  display: block;
  object-fit: contain;
}
.video-tip {
  text-align: center;
  margin-top: 14px;
  font-size: 13px;
  color: var(--muted);
}
@media (prefers-reduced-motion: reduce) {
  .photo-scroll-track { animation: none; }
}