/* ============================================================
   HVAC Exam Master — 子页面公共样式
   Page Hero / Breadcrumb / Content Layout / Article / Quiz Preview
   FAQ / Bottom Links / CTA / Image / Sidebar / Footer / Mobile Nav
   / 基础响应式

   由 10 个子页面共同引用（shell.css 之后加载）。
   各页面仅需在自身 <style> 中保留真正特有的选择器。
   ============================================================ */

/* ================= Page Hero ================= */
.page-hero {
  background:
    linear-gradient(rgba(15, 23, 42, 0.9), rgba(15, 23, 42, 0.85)),
    url('/image/hero-bg.jpg') center/cover;
  color: white;
  padding: 160px 0 80px;
  text-align: center;
}

.page-hero h1 {
  font-size: 42px;
  font-weight: 900;
  margin-bottom: 16px;
}

.page-hero p {
  font-size: 20px;
  color: #cbd5e1;
  max-width: 700px;
  margin: 0 auto;
}

/* ================= Breadcrumb ================= */
.breadcrumb {
  font-size: 14px;
  color: #94a3b8;
  text-transform: uppercase;
  letter-spacing: 1px;
  margin-bottom: 15px;
  font-weight: 700;
}

.breadcrumb a {
  color: #cbd5e1;
  text-decoration: none;
}

.breadcrumb a:hover {
  color: white;
}

/* ================= Content Area ================= */
.content-wrapper {
  padding: 60px 0 80px;
  background: var(--bg-light);
}

.content-flex {
  display: flex;
  gap: 60px;
  align-items: flex-start;
}

.main-content {
  flex: 2;
  min-width: 0;
}

.sidebar {
  flex: 1;
  position: sticky;
  top: 100px;
  min-width: 300px;
}

/* ================= Article Block ================= */
.article-block {
  margin-bottom: 40px;
  background: white;
  padding: 40px;
  border-radius: 12px;
  border: 1px solid var(--border);
  box-shadow: 0 4px 6px rgba(0, 0, 0, 0.02);
}

.article-block h2 {
  font-size: 28px;
  font-weight: 800;
  color: var(--primary-dark);
  margin-top: 0;
  margin-bottom: 20px;
  padding-bottom: 10px;
  border-bottom: 2px solid var(--bg-light);
}

.article-block h3 {
  font-size: 22px;
  font-weight: 700;
  color: var(--primary-blue);
  margin-top: 30px;
  margin-bottom: 15px;
}

.article-block p {
  font-size: 17px;
  color: var(--text-light);
  margin-bottom: 20px;
  line-height: 1.8;
}

.article-block ul {
  margin-bottom: 30px;
  padding-left: 10px;
}

.article-block li {
  margin-bottom: 14px;
  font-size: 17px;
  color: var(--text-main);
  position: relative;
  padding-left: 35px;
}

.article-block li::before {
  content: '\f058';
  font-family: 'Font Awesome 6 Free';
  font-weight: 900;
  color: var(--accent);
  position: absolute;
  left: 0;
  top: 3px;
  font-size: 18px;
}

/* ================= Quiz Preview Cards ================= */
.quiz-preview-container {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
  margin-top: 30px;
}

.quiz-preview-card {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 25px;
  position: relative;
  transition: all 0.3s ease;
  cursor: pointer;
  text-decoration: none;
  display: block;
}

.quiz-preview-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 15px 30px rgba(0, 0, 0, 0.1);
  border-color: var(--primary-blue);
}

.q-tag {
  background: #fff7ed;
  color: var(--accent);
  font-size: 12px;
  font-weight: 700;
  padding: 4px 8px;
  border-radius: 4px;
  display: inline-block;
  margin-bottom: 10px;
}

.q-text {
  font-weight: 700;
  color: var(--primary-dark);
  margin-bottom: 15px;
  line-height: 1.4;
  font-size: 16px;
}

.q-options {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.q-opt {
  background: #f8fafc;
  border: 1px solid #e2e8f0;
  padding: 8px 12px;
  border-radius: 6px;
  font-size: 14px;
  color: var(--text-light);
  transition: 0.2s;
}

.quiz-preview-card:hover .q-opt:nth-child(2) {
  background: #eff6ff;
  border-color: var(--primary-blue);
  color: var(--primary-blue);
  font-weight: 600;
}

.click-hint {
  margin-top: 15px;
  font-size: 13px;
  color: var(--accent);
  font-weight: 700;
  text-align: center;
  opacity: 0;
  transition: 0.3s;
}

.quiz-preview-card:hover .click-hint {
  opacity: 1;
}

/* ================= FAQ Cards ================= */
.faq-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 20px;
}

.faq-card {
  background: #f8fafc;
  border-left: 4px solid var(--accent);
  padding: 20px 25px;
  border-radius: 0 8px 8px 0;
}

.faq-q {
  font-weight: 800;
  color: var(--primary-dark);
  font-size: 16px;
  margin: 0 0 8px;
  display: block;
}

.faq-a {
  font-size: 15px;
  color: var(--text-light);
  margin: 0;
  line-height: 1.6;
}

/* ================= Bottom Link Cards ================= */
.bottom-links-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 25px;
  margin-top: 30px;
}

.bottom-link-card {
  text-align: center;
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 30px 20px;
  transition: all 0.3s ease;
  text-decoration: none;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  background: white;
}

.bottom-link-card:hover {
  border-color: var(--primary-blue);
  transform: translateY(-5px);
  box-shadow: 0 10px 25px rgba(0, 0, 0, 0.08);
}

.bottom-link-icon {
  color: var(--primary-blue);
  font-size: 32px;
  margin-bottom: 15px;
  background: #f0f9ff;
  width: 60px;
  height: 60px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
}

.bottom-link-title {
  font-weight: 800;
  color: var(--primary-dark);
  font-size: 18px;
  display: block;
  margin-bottom: 5px;
}

.bottom-link-text {
  font-size: 14px;
  color: var(--text-light);
}

/* ================= Bottom CTA Box ================= */
.bottom-cta-box {
  background: linear-gradient(135deg, #0056b3 0%, #003366 100%);
  color: white;
  padding: 50px 30px;
  border-radius: 16px;
  text-align: center;
  margin-top: 50px;
  box-shadow: 0 20px 40px rgba(0, 86, 179, 0.25);
  position: relative;
  overflow: hidden;
}

.bottom-cta-box::before {
  content: '';
  position: absolute;
  top: -50px;
  right: -50px;
  width: 200px;
  height: 200px;
  background: rgba(255, 255, 255, 0.1);
  border-radius: 50%;
}

.bottom-cta-box h2 {
  color: white !important;
  border: none !important;
  margin-top: 0;
  margin-bottom: 15px;
  font-size: 32px;
}

.bottom-cta-box p {
  color: #e0e7ff !important;
  font-size: 18px !important;
  margin-bottom: 30px;
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
}

/* ================= Image & Caption ================= */
.content-img {
  width: 100%;
  border-radius: 8px;
  margin: 20px 0;
  border: 1px solid var(--border);
}

.img-caption {
  text-align: center;
  font-size: 13px;
  color: #999;
  margin-top: -10px;
  margin-bottom: 30px;
  font-style: italic;
}

/* ================= Sidebar ================= */
.sidebar-card {
  background: white;
  padding: 30px;
  border-radius: 12px;
  border: 1px solid var(--border);
  margin-bottom: 30px;
}

.sidebar-title {
  font-size: 20px;
  font-weight: 800;
  color: var(--primary-dark);
  margin-bottom: 15px;
}

.sidebar-list li {
  border-bottom: 1px solid #e2e8f0;
  padding-bottom: 10px;
  margin-bottom: 15px;
  padding-left: 0;
}

.sidebar-list li::before {
  content: none;
}

.sidebar-list a {
  font-weight: 600;
  color: var(--text-main);
  font-size: 15px;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.sidebar-list a:hover {
  color: var(--primary-blue);
}

.sidebar-list a::after {
  content: '\f054';
  font-family: 'Font Awesome 6 Free';
  font-weight: 900;
  font-size: 12px;
  color: #ccc;
}

/* ================= 基础响应式布局适配 (900px) ================= */
/* Footer / 移动端导航已迁入 shell.css（全站共用） */
@media (max-width: 900px) {
  .content-flex {
    flex-direction: column;
  }

  .sidebar {
    width: 100%;
  }

  .quiz-preview-container {
    grid-template-columns: 1fr;
  }

  .bottom-links-grid {
    grid-template-columns: 1fr;
  }
}