/* ============================================
   枪械大观 · 科普与亲子DIY指南
   军事工业风配色：深钢蓝 + 安全橙 + 卡其绿
   ============================================ */

/* 设计令牌 */
:root {
  --color-bg: #f0f2f5;
  --color-surface: #ffffff;
  --color-primary: #1a2332;
  --color-primary-light: #2d3e50;
  --color-accent: #ff6b35;
  --color-accent-light: #ff8c5e;
  --color-secondary: #4a6b3a;
  --color-text: #1a2332;
  --color-text-light: #5a6c7d;
  --color-text-muted: #8899aa;
  --color-border: #d1d8e0;
  --color-card-bg: #ffffff;
  --color-danger: #e74c3c;
  --color-success: #2ecc71;
  --color-warning: #f39c12;
  --color-info: #3498db;

  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 22px;
  --radius-xl: 28px;

  --shadow-sm: 0 2px 8px rgba(26,35,50,0.08);
  --shadow-md: 0 4px 20px rgba(26,35,50,0.10);
  --shadow-lg: 0 8px 40px rgba(26,35,50,0.14);
  --shadow-xl: 0 16px 60px rgba(26,35,50,0.18);

  --nav-height: 64px;
  --sidebar-width: 260px;
  --container-width: 1080px;

  --font-stack: "PingFang SC","Microsoft YaHei","Helvetica Neue",Arial,sans-serif;
  --font-mono: "SF Mono","Fira Code","Consolas",monospace;

  --transition-fast: 0.2s ease;
  --transition-base: 0.35s cubic-bezier(0.4,0,0.2,1);
  --transition-slow: 0.6s cubic-bezier(0.4,0,0.2,1);
}

/* 全局重置 */
*,*::before,*::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; scroll-padding-top: var(--nav-height); }
body {
  font-family: var(--font-stack);
  background: var(--color-bg);
  color: var(--color-text);
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

/* ========== 顶部导航栏 ========== */
.navbar {
  position: fixed; top:0; left:0; right:0; height: var(--nav-height);
  z-index: 1000;
  background: rgba(26,35,50,0.82);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid rgba(255,255,255,0.08);
  transition: background var(--transition-base);
}
.navbar.scrolled {
  background: rgba(26,35,50,0.95);
  box-shadow: var(--shadow-md);
}
.nav-inner {
  max-width: 1400px; margin: 0 auto; height: 100%;
  display: flex; align-items: center; justify-content: space-between;
  padding: 0 24px;
}
.nav-logo {
  display: flex; align-items: center; gap: 8px;
  text-decoration: none; color: #fff;
  font-weight: 700; font-size: 18px; letter-spacing: 1px;
}
.logo-icon { font-size: 24px; }
.logo-text { background: linear-gradient(90deg, #fff, #ff8c5e); -webkit-background-clip: text; -webkit-text-fill-color: transparent; }
.nav-links {
  display: flex; list-style: none; gap: 4px;
}
.nav-links li a {
  display: block; padding: 8px 14px;
  color: rgba(255,255,255,0.75); text-decoration: none;
  font-size: 14px; font-weight: 500; border-radius: var(--radius-sm);
  transition: all var(--transition-fast);
}
.nav-links li a:hover {
  color: #fff; background: rgba(255,107,53,0.15);
}
.nav-links li a.active {
  color: #fff; background: var(--color-accent);
}
.nav-toggle {
  display: none; flex-direction: column; gap: 5px;
  background: none; border: none; cursor: pointer; padding: 8px;
}
.nav-toggle span {
  width: 24px; height: 2px; background: #fff; border-radius: 2px;
  transition: all var(--transition-base);
}
.nav-toggle.open span:nth-child(1) { transform: rotate(45deg) translate(5px,5px); }
.nav-toggle.open span:nth-child(2) { opacity: 0; }
.nav-toggle.open span:nth-child(3) { transform: rotate(-45deg) translate(5px,-5px); }

/* ========== Hero 区 ========== */
.hero {
  position: relative; min-height: 100vh;
  display: flex; align-items: center; justify-content: center;
  overflow: hidden;
}
.hero-bg {
  position: absolute; inset: 0;
  background:
    radial-gradient(ellipse at 20% 30%, rgba(255,107,53,0.15) 0%, transparent 50%),
    radial-gradient(ellipse at 80% 70%, rgba(74,107,58,0.12) 0%, transparent 50%),
    linear-gradient(135deg, #1a2332 0%, #2d3e50 50%, #1a2332 100%);
}
.hero-bg::before {
  content: ''; position: absolute; inset: 0;
  background-image:
    repeating-linear-gradient(0deg, transparent, transparent 39px, rgba(255,255,255,0.03) 39px, rgba(255,255,255,0.03) 40px),
    repeating-linear-gradient(90deg, transparent, transparent 39px, rgba(255,255,255,0.03) 39px, rgba(255,255,255,0.03) 40px);
}
.hero-bg::after {
  content: ''; position: absolute; inset: 0;
  background: radial-gradient(circle at center, transparent 0%, rgba(26,35,50,0.5) 100%);
}
.hero-content {
  position: relative; z-index: 2; text-align: center;
  padding: 0 24px; max-width: 800px;
}
.hero-kicker {
  color: var(--color-accent); font-size: 16px; font-weight: 600;
  letter-spacing: 3px; text-transform: uppercase; margin-bottom: 16px;
  animation: fadeUp 0.8s ease both;
}
.hero-title {
  font-size: clamp(48px, 8vw, 88px); font-weight: 900;
  color: #fff; letter-spacing: 2px;
  text-shadow: 0 4px 30px rgba(255,107,53,0.3);
  animation: fadeUp 0.8s ease 0.15s both;
}
.hero-subtitle {
  font-size: clamp(16px, 2.5vw, 20px); color: rgba(255,255,255,0.8);
  margin: 24px auto 32px; line-height: 1.7; max-width: 600px;
  animation: fadeUp 0.8s ease 0.3s both;
}
.hero-tags {
  display: flex; flex-wrap: wrap; gap: 12px; justify-content: center;
  margin-bottom: 40px; animation: fadeUp 0.8s ease 0.45s both;
}
.tag {
  padding: 8px 18px; border-radius: 100px;
  background: rgba(255,255,255,0.08); border: 1px solid rgba(255,255,255,0.12);
  color: rgba(255,255,255,0.9); font-size: 14px; font-weight: 500;
  backdrop-filter: blur(10px);
}
.hero-btn {
  display: inline-block; padding: 16px 48px;
  background: linear-gradient(135deg, var(--color-accent), var(--color-accent-light));
  color: #fff; font-size: 18px; font-weight: 700; text-decoration: none;
  border-radius: 100px; box-shadow: 0 8px 30px rgba(255,107,53,0.4);
  transition: all var(--transition-base);
  animation: fadeUp 0.8s ease 0.6s both;
}
.hero-btn:hover {
  transform: translateY(-3px); box-shadow: 0 12px 40px rgba(255,107,53,0.55);
}
@keyframes fadeUp {
  from { opacity: 0; transform: translateY(30px); }
  to { opacity: 1; transform: translateY(0); }
}

/* ========== 布局：侧边栏 + 主内容 ========== */
.layout-wrapper {
  display: flex; max-width: 1400px; margin: 0 auto; position: relative;
}

/* 左侧导航 */
.sidebar {
  width: var(--sidebar-width); flex-shrink: 0;
  position: sticky; top: var(--nav-height);
  height: calc(100vh - var(--nav-height)); overflow-y: auto;
  padding: 32px 20px; background: transparent;
}
.sidebar-inner { position: relative; }
.sidebar-title {
  font-size: 14px; font-weight: 700; color: var(--color-text-light);
  margin-bottom: 16px; letter-spacing: 1px;
}
.sidebar-nav { list-style: none; }
.sidebar-nav li { margin-bottom: 2px; }
.sidebar-nav li a {
  display: block; padding: 10px 16px;
  color: var(--color-text-light); text-decoration: none;
  font-size: 14px; font-weight: 500; border-radius: var(--radius-sm);
  transition: all var(--transition-fast);
  border-left: 3px solid transparent;
}
.sidebar-nav li a:hover {
  color: var(--color-primary); background: rgba(255,107,53,0.08);
  border-left-color: var(--color-accent);
}
.sidebar-nav li a.active {
  color: var(--color-accent); background: rgba(255,107,53,0.1);
  border-left-color: var(--color-accent); font-weight: 700;
}
.sidebar-nav li a.nav-highlight {
  color: var(--color-accent); font-weight: 700;
}
.sidebar-progress {
  margin-top: 24px; height: 4px; border-radius: 2px;
  background: var(--color-border); overflow: hidden;
}
.progress-bar {
  height: 100%; width: 0%; border-radius: 2px;
  background: linear-gradient(90deg, var(--color-accent), var(--color-accent-light));
  transition: width 0.1s linear;
}
.sidebar-progress-text {
  text-align: center; font-size: 12px; color: var(--color-text-muted);
  margin-top: 8px; font-weight: 600;
}

/* 主内容区 */
.main-content {
  flex: 1; min-width: 0; padding: 48px 48px;
}

/* ========== 章节通用 ========== */
.chapter {
  margin-bottom: 80px; scroll-margin-top: calc(var(--nav-height) + 20px);
}
.chapter-header {
  display: flex; flex-direction: column; gap: 8px;
  margin-bottom: 40px; padding-bottom: 24px;
  border-bottom: 2px solid var(--color-border);
  position: relative;
}
.chapter-num {
  font-size: 14px; font-weight: 800; color: var(--color-accent);
  letter-spacing: 3px; font-family: var(--font-mono);
}
.chapter-title {
  font-size: clamp(28px, 4vw, 40px); font-weight: 900;
  color: var(--color-primary); letter-spacing: 1px;
}
.chapter-desc {
  font-size: 16px; color: var(--color-text-light); margin-top: 4px;
}

/* DIY 章节特殊配色 */
.diy-header { border-bottom-color: var(--color-accent); }
.diy-num { color: var(--color-accent); }
.diy-title { color: var(--color-accent); }

/* ========== 内容块 ========== */
.content-block {
  background: var(--color-surface); border-radius: var(--radius-lg);
  padding: 36px; margin-bottom: 28px;
  box-shadow: var(--shadow-sm);
  transition: box-shadow var(--transition-base);
}
.content-block:hover { box-shadow: var(--shadow-md); }
.content-block h3 {
  font-size: 22px; font-weight: 700; color: var(--color-primary);
  margin-bottom: 16px; padding-bottom: 12px;
  border-bottom: 2px solid rgba(255,107,53,0.15);
}
.content-block p {
  margin-bottom: 16px; color: var(--color-text); line-height: 1.85;
}
.content-block strong { color: var(--color-primary); font-weight: 700; }

/* ========== 图示区 ========== */
.figure-block {
  background: var(--color-surface); border-radius: var(--radius-lg);
  padding: 28px; margin-bottom: 28px;
  box-shadow: var(--shadow-sm); text-align: center;
}
.figure-svg {
  display: flex; justify-content: center; align-items: center;
  min-height: 200px;
}
.figure-svg svg { max-width: 100%; height: auto; }
.figure-caption {
  margin-top: 16px; font-size: 14px; color: var(--color-text-muted);
  font-style: italic;
}

/* ========== 卡片网格 ========== */
.card-grid {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 20px; margin-top: 20px;
}
.info-card {
  background: linear-gradient(135deg, #f8f9fa, #ffffff);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md); padding: 24px;
  transition: all var(--transition-base);
}
.info-card:hover {
  transform: translateY(-4px); box-shadow: var(--shadow-md);
  border-color: var(--color-accent);
}
.card-icon { font-size: 32px; display: block; margin-bottom: 12px; }
.info-card h4 {
  font-size: 17px; font-weight: 700; color: var(--color-primary);
  margin-bottom: 8px;
}
.info-card p { font-size: 14px; color: var(--color-text-light); line-height: 1.7; }

/* ========== Q&A 折叠列表 ========== */
.qa-list { margin-top: 20px; }
.qa-item {
  border: 1px solid var(--color-border); border-radius: var(--radius-md);
  margin-bottom: 12px; overflow: hidden;
  transition: all var(--transition-fast);
}
.qa-item:hover { border-color: var(--color-accent-light); }
.qa-item.open { border-color: var(--color-accent); box-shadow: var(--shadow-sm); }
.qa-q {
  padding: 16px 20px; font-size: 16px; font-weight: 600;
  color: var(--color-primary); cursor: pointer;
  display: flex; justify-content: space-between; align-items: center;
  transition: background var(--transition-fast);
}
.qa-q::after { content: '▸'; color: var(--color-accent); font-size: 18px; transition: transform var(--transition-fast); }
.qa-item.open .qa-q { background: rgba(255,107,53,0.06); }
.qa-item.open .qa-q::after { transform: rotate(90deg); }
.qa-a {
  max-height: 0; overflow: hidden;
  transition: max-height var(--transition-slow);
}
.qa-item.open .qa-a { max-height: 500px; }
.qa-a p { padding: 16px 20px; color: var(--color-text-light); line-height: 1.85; }

/* ========== 时间线 ========== */
.timeline {
  position: relative; padding-left: 40px; margin-top: 24px;
}
.timeline::before {
  content: ''; position: absolute; left: 12px; top: 0; bottom: 0;
  width: 3px; background: linear-gradient(180deg, var(--color-accent), var(--color-secondary));
  border-radius: 2px;
}
.timeline-item {
  position: relative; margin-bottom: 28px;
}
.timeline-dot {
  position: absolute; left: -34px; top: 4px;
  width: 14px; height: 14px; border-radius: 50%;
  background: var(--color-accent); border: 3px solid #fff;
  box-shadow: 0 0 0 3px rgba(255,107,53,0.25);
}
.timeline-content {
  background: var(--color-surface); border-radius: var(--radius-md);
  padding: 20px; box-shadow: var(--shadow-sm);
  border-left: 4px solid var(--color-accent);
}
.timeline-content h4 {
  font-size: 18px; font-weight: 700; color: var(--color-primary);
  margin-bottom: 8px;
}
.timeline-content p { font-size: 15px; color: var(--color-text-light); }

/* ========== 步骤流程 ========== */
.step-flow {
  display: flex; flex-wrap: wrap; gap: 12px; align-items: stretch;
  margin-top: 20px;
}
.step-item {
  flex: 1; min-width: 180px;
  background: linear-gradient(135deg, #f8f9fa, #fff);
  border: 1px solid var(--color-border); border-radius: var(--radius-md);
  padding: 20px; position: relative;
}
.step-num {
  display: inline-flex; align-items: center; justify-content: center;
  width: 36px; height: 36px; border-radius: 50%;
  background: var(--color-accent); color: #fff;
  font-weight: 800; font-size: 16px; margin-bottom: 12px;
}
.step-item h4 { font-size: 16px; font-weight: 700; color: var(--color-primary); margin-bottom: 8px; }
.step-item p { font-size: 14px; color: var(--color-text-light); line-height: 1.7; }
.step-num-arrow {
  display: flex; align-items: center; font-size: 24px;
  color: var(--color-accent); font-weight: 700;
}

/* ========== 洞见列表 ========== */
.insight-list { list-style: none; margin-top: 16px; }
.insight-list li {
  padding: 12px 0 12px 28px; position: relative;
  font-size: 15px; color: var(--color-text); line-height: 1.8;
}
.insight-list li::before {
  content: '▸'; position: absolute; left: 0; top: 12px;
  color: var(--color-accent); font-weight: 700; font-size: 18px;
}
.insight-list li strong { color: var(--color-primary); }

/* ========== 枪械实拍图 ========== */
.gun-photo {
  width: 100%; max-width: 600px; height: auto;
  border-radius: var(--radius-md); margin: 16px auto 0;
  display: block; box-shadow: var(--shadow-sm);
  border: 1px solid var(--color-border);
}
.gun-photo-caption {
  text-align: center; font-size: 13px; color: var(--color-text-muted);
  margin-top: 8px; font-style: italic;
}
.figure-img-block {
  background: var(--color-surface); border-radius: var(--radius-lg);
  padding: 28px; margin-bottom: 28px; box-shadow: var(--shadow-sm); text-align: center;
}
.figure-img-block img {
  max-width: 100%; height: auto; border-radius: var(--radius-md);
  border: 1px solid var(--color-border);
}

/* ========== 枪械类型卡片 ========== */
.gun-type-card {
  background: var(--color-surface); border-radius: var(--radius-lg);
  margin-bottom: 24px; overflow: hidden; box-shadow: var(--shadow-sm);
  transition: box-shadow var(--transition-base);
}
.gun-type-card:hover { box-shadow: var(--shadow-lg); }
.gun-type-header {
  padding: 20px 28px; display: flex; justify-content: space-between; align-items: center;
  background: linear-gradient(135deg, rgba(26,35,50,0.03), rgba(255,107,53,0.03));
}
.gun-type-header h3 { font-size: 22px; font-weight: 800; color: var(--color-primary); }
.gun-type-tag {
  font-size: 13px; color: var(--color-text-muted); font-weight: 500;
  background: rgba(26,35,50,0.06); padding: 6px 14px; border-radius: 100px;
}
.gun-type-body { padding: 24px 28px; }
.gun-type-body p { margin-bottom: 14px; font-size: 15px; line-height: 1.85; color: var(--color-text); }
.gun-type-body p:last-child { margin-bottom: 0; }

/* ========== 子弹解剖 ========== */
.bullet-anatomy {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(200px,1fr));
  gap: 16px; margin-top: 20px;
}
.bullet-part {
  background: var(--color-surface); border: 1px solid var(--color-border);
  border-radius: var(--radius-md); padding: 20px;
  text-align: center;
}
.bullet-label {
  display: inline-block; padding: 6px 18px; border-radius: 100px;
  color: #fff; font-size: 14px; font-weight: 700; margin-bottom: 12px;
}
.bullet-part p { font-size: 14px; color: var(--color-text-light); line-height: 1.7; }

/* ========== DIY 工坊 ========== */
.safety-notice {
  background: linear-gradient(135deg, #fff5f0, #fff);
  border: 2px solid var(--color-accent); border-radius: var(--radius-lg);
  padding: 28px; margin-bottom: 32px;
}
.safety-notice h3 { color: var(--color-accent); font-size: 20px; font-weight: 700; margin-bottom: 12px; }
.safety-notice p { font-size: 15px; color: var(--color-text); line-height: 1.85; margin-bottom: 20px; }
.safety-rules {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(160px,1fr));
  gap: 12px;
}
.rule-item {
  text-align: center; padding: 12px; font-size: 14px; font-weight: 600;
  color: var(--color-secondary); background: rgba(74,107,58,0.08);
  border-radius: var(--radius-sm);
}

/* DIY Tab 导航 */
.diy-tabs {
  display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 28px;
  padding-bottom: 4px;
}
.diy-tab {
  padding: 10px 20px; border: 2px solid var(--color-border);
  background: var(--color-surface); border-radius: 100px;
  font-size: 14px; font-weight: 600; color: var(--color-text-light);
  cursor: pointer; transition: all var(--transition-fast);
  font-family: var(--font-stack);
}
.diy-tab:hover { border-color: var(--color-accent-light); color: var(--color-accent); }
.diy-tab.active {
  background: var(--color-accent); border-color: var(--color-accent);
  color: #fff; box-shadow: 0 4px 16px rgba(255,107,53,0.3);
}

/* DIY 内容区 */
.diy-content { display: none; animation: fadeIn 0.5s ease; }
.diy-content.active { display: block; }
@keyframes fadeIn { from { opacity: 0; transform: translateY(10px); } to { opacity: 1; transform: translateY(0); } }

.diy-meta { display: flex; flex-wrap: wrap; gap: 10px; margin-bottom: 20px; }
.meta-tag {
  padding: 6px 16px; border-radius: 100px; font-size: 13px; font-weight: 600;
}
.difficulty-easy { background: rgba(46,204,113,0.12); color: #27ae60; }
.difficulty-medium { background: rgba(243,156,18,0.12); color: #e67e22; }
.time-15, .time-20, .time-30, .time-40, .time-45 { background: rgba(52,152,219,0.12); color: #2980b9; }
.age-5, .age-6, .age-7 { background: rgba(155,89,182,0.12); color: #8e44ad; }

.diy-content > h3 {
  font-size: 26px; font-weight: 800; color: var(--color-primary);
  margin-bottom: 12px;
}
.diy-intro {
  font-size: 16px; color: var(--color-text-light); line-height: 1.85;
  margin-bottom: 24px;
}

/* DIY 材料清单 */
.diy-materials {
  background: linear-gradient(135deg, #f8f9fa, #fff);
  border: 1px solid var(--color-border); border-radius: var(--radius-md);
  padding: 24px; margin-bottom: 24px;
}
.diy-materials h4 { font-size: 17px; font-weight: 700; color: var(--color-primary); margin-bottom: 12px; }
.diy-materials ul { list-style: none; }
.diy-materials li {
  padding: 8px 0 8px 24px; position: relative; font-size: 15px; color: var(--color-text);
}
.diy-materials li::before {
  content: '✓'; position: absolute; left: 0; color: var(--color-accent); font-weight: 700;
}

/* DIY 步骤 */
.diy-steps { margin-top: 24px; }
.diy-steps > h4, .dy-steps > h4 {
  font-size: 18px; font-weight: 700; color: var(--color-primary); margin-bottom: 16px;
}
.step-card {
  display: flex; gap: 20px; margin-bottom: 16px;
  background: var(--color-surface); border: 1px solid var(--color-border);
  border-radius: var(--radius-md); padding: 20px;
  transition: all var(--transition-fast);
}
.step-card:hover { border-color: var(--color-accent); box-shadow: var(--shadow-sm); }
.step-num-big {
  flex-shrink: 0; display: flex; align-items: center; justify-content: center;
  width: 44px; height: 44px; border-radius: 50%;
  background: linear-gradient(135deg, var(--color-accent), var(--color-accent-light));
  color: #fff; font-size: 20px; font-weight: 800;
}
.step-card h5 { font-size: 17px; font-weight: 700; color: var(--color-primary); margin-bottom: 6px; }
.step-card p { font-size: 15px; color: var(--color-text-light); line-height: 1.75; }
.step-card strong { color: var(--color-accent); }

/* DIY 科学知识 */
.diy-science {
  background: linear-gradient(135deg, #eef5ff, #f8f9fa);
  border-left: 4px solid var(--color-info);
  border-radius: var(--radius-md); padding: 24px; margin-top: 24px;
}
.diy-science h4 { font-size: 17px; font-weight: 700; color: var(--color-info); margin-bottom: 10px; }
.diy-science p { font-size: 15px; color: var(--color-text); line-height: 1.85; }

/* DIY 总结 */
.diy-summary {
  background: linear-gradient(135deg, var(--color-primary), var(--color-primary-light));
  border-radius: var(--radius-lg); padding: 36px; color: #fff;
  margin-top: 40px;
}
.diy-summary h3 { color: #fff; font-size: 24px; font-weight: 800; margin-bottom: 16px; }
.diy-summary p { color: rgba(255,255,255,0.85); font-size: 16px; line-height: 1.85; margin-bottom: 24px; }
.energy-flow {
  display: flex; flex-wrap: wrap; align-items: center; justify-content: center;
  gap: 12px; margin: 28px 0;
}
.energy-step {
  text-align: center; padding: 20px 24px;
  background: rgba(255,255,255,0.1); border: 1px solid rgba(255,255,255,0.15);
  border-radius: var(--radius-md); min-width: 160px;
}
.energy-step strong { color: var(--color-accent); font-size: 18px; display: block; margin-top: 4px; }
.energy-arrow { color: var(--color-accent); font-size: 20px; font-weight: 700; }

/* ========== 法规卡片 ========== */
.law-card-grid {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(300px,1fr));
  gap: 20px; margin-top: 20px;
}
.law-card {
  background: var(--color-surface); border: 1px solid var(--color-border);
  border-radius: var(--radius-md); padding: 24px;
}
.law-card h4 { font-size: 17px; font-weight: 700; color: var(--color-primary); margin-bottom: 12px; }
.law-card ul { list-style: none; }
.law-card li {
  padding: 8px 0 8px 20px; position: relative; font-size: 14px; color: var(--color-text-light);
  line-height: 1.7; border-bottom: 1px solid rgba(0,0,0,0.04);
}
.law-card li:last-child { border-bottom: none; }
.law-card li::before { content: '•'; position: absolute; left: 4px; color: var(--color-accent); font-weight: 700; }
.law-card li strong { color: var(--color-danger); }

/* 警告框 */
.warning-box {
  background: #fff5f5; border-left: 4px solid var(--color-danger);
  border-radius: var(--radius-sm); padding: 16px 20px; margin-top: 20px;
}
.warning-box p { font-size: 15px; color: var(--color-text); line-height: 1.8; margin: 0; }
.warning-box strong { color: var(--color-danger); }

/* 安全原则 */
.safety-principles {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(220px,1fr));
  gap: 16px; margin-top: 20px;
}
.principle-card {
  background: var(--color-surface); border: 2px solid var(--color-border);
  border-radius: var(--radius-md); padding: 24px; text-align: center;
  transition: all var(--transition-base);
}
.principle-card:hover { border-color: var(--color-accent); transform: translateY(-2px); }
.principle-num {
  display: inline-flex; align-items: center; justify-content: center;
  width: 48px; height: 48px; border-radius: 50%;
  background: linear-gradient(135deg, var(--color-accent), var(--color-accent-light));
  color: #fff; font-size: 22px; font-weight: 800; margin-bottom: 12px;
}
.principle-card h4 { font-size: 16px; font-weight: 700; color: var(--color-primary); margin-bottom: 8px; }
.principle-card p { font-size: 14px; color: var(--color-text-light); line-height: 1.7; }

/* ========== 页脚 ========== */
.footer {
  background: var(--color-primary); color: rgba(255,255,255,0.8);
  padding: 48px 24px; text-align: center; margin-top: 80px;
}
.footer-inner { max-width: 800px; margin: 0 auto; }
.footer-title { font-size: 20px; font-weight: 700; color: #fff; margin-bottom: 12px; }
.footer-text { font-size: 14px; line-height: 1.8; color: rgba(255,255,255,0.6); margin-bottom: 20px; }
.footer-copy { font-size: 13px; color: rgba(255,255,255,0.4); }

/* ========== 回到顶部 ========== */
.back-to-top {
  position: fixed; bottom: 32px; right: 32px;
  width: 48px; height: 48px; border-radius: 50%;
  background: var(--color-accent); color: #fff; border: none;
  font-size: 22px; cursor: pointer; z-index: 999;
  box-shadow: var(--shadow-md); opacity: 0; visibility: hidden;
  transition: all var(--transition-base);
}
.back-to-top.visible { opacity: 1; visibility: visible; }
.back-to-top:hover { transform: translateY(-4px); box-shadow: var(--shadow-lg); }

/* ========== 滚动渐入动画 ========== */
.reveal {
  opacity: 0; transform: translateY(40px);
  transition: opacity 0.7s ease, transform 0.7s ease;
}
.reveal.visible { opacity: 1; transform: translateY(0); }

/* ========== 响应式适配 ========== */
@media (max-width: 1024px) {
  .sidebar { display: none; }
  .main-content { padding: 32px 24px; }
}
@media (max-width: 768px) {
  .nav-links {
    display: none; position: fixed; top: var(--nav-height); left: 0; right: 0;
    flex-direction: column; background: rgba(26,35,50,0.98);
    padding: 16px; gap: 4px; backdrop-filter: blur(20px);
  }
  .nav-links.open { display: flex; }
  .nav-toggle { display: flex; }
  .main-content { padding: 24px 16px; }
  .content-block { padding: 24px 16px; }
  .figure-block { padding: 16px; }
  .card-grid { grid-template-columns: 1fr; }
  .step-flow { flex-direction: column; }
  .step-num-arrow { display: none; }
  .step-card { flex-direction: column; gap: 12px; }
  .gun-type-header { flex-direction: column; align-items: flex-start; gap: 8px; }
  .gun-type-body { padding: 20px 16px; }
  .hero-tags { gap: 8px; }
  .tag { font-size: 13px; padding: 6px 12px; }
  .diy-tabs { gap: 6px; }
  .diy-tab { padding: 8px 14px; font-size: 13px; }
  .energy-flow { flex-direction: column; }
  .energy-arrow { transform: rotate(90deg); }
  .back-to-top { bottom: 20px; right: 20px; width: 40px; height: 40px; font-size: 18px; }
}
@media (max-width: 480px) {
  .hero-title { font-size: 42px; }
  .chapter-title { font-size: 26px; }
  .content-block h3 { font-size: 20px; }
  .diy-content > h3 { font-size: 22px; }
  .bullet-anatomy { grid-template-columns: 1fr; }
  .safety-rules { grid-template-columns: 1fr 1fr; }
}