/* 全局样式 */
/* 性能优化：启用CSS硬件加速 */
* {
  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;
  -moz-backface-visibility: hidden;
  -ms-backface-visibility: hidden;
}

/* 性能优化：减少重排 */
img {
  max-width: 100%;
  height: auto;
  display: block;
}

/* 性能优化：CSS动画使用transform和opacity */
.fade-in, .fade-in-left, .fade-in-right, .scale-in {
  will-change: transform, opacity;
}

/* 性能优化：预加载关键资源 */
@import url('https://fonts.googleapis.com/css2?family=Noto+Sans+SC:wght@300;400;500;700&display=swap');

:root {
  --primary-color: #007bff;
  --primary-hover: #0069d9;
  --secondary-color: #6c757d;
  --success-color: #28a745;
  --danger-color: #dc3545;
  --warning-color: #ffc107;
  --info-color: #17a2b8;
  --light-color: #f8f9fa;
  --dark-color: #343a40;
  --text-color: #333;
  --text-muted: #6c757d;
  --border-color: #dee2e6;
  --shadow-sm: 0 0.125rem 0.25rem rgba(0, 0, 0, 0.075);
  --shadow-md: 0 0.5rem 1rem rgba(0, 0, 0, 0.15);
  --shadow-lg: 0 1rem 3rem rgba(0, 0, 0, 0.175);
  --border-radius-sm: 0.25rem;
  --border-radius-md: 0.375rem;
  --border-radius-lg: 0.5rem;
  --transition: all 0.3s ease;
}

body {
  font-family: 'Microsoft YaHei', Arial, sans-serif;
  color: var(--text-color);
  line-height: 1.6;
  background-color: var(--light-color);
}

/* 间距类 */
.py-12 {
  padding-top: 120px;
  padding-bottom: 120px;
}

.mb-10 {
  margin-bottom: 100px;
}

.mb-6 {
  margin-bottom: 60px;
}

.mb-4 {
  margin-bottom: 40px;
}

.mb-3 {
  margin-bottom: 30px;
}

.mb-2 {
  margin-bottom: 20px;
}

/* 卡片样式 */
.feature-card,
.service-card,
.store-card,
.order-form,
.contact-info,
.contact-form {
  transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.feature-card:hover,
.service-card:hover,
.store-card:hover,
.order-form:hover,
.contact-info:hover,
.contact-form:hover {
  transform: translateY(-5px);
  box-shadow: 0 10px 20px rgba(0, 0, 0, 0.1);
}

/* 按钮样式 */
.btn-primary {
  background-color: var(--primary-color) !important;
  border-color: var(--primary-color) !important;
  transition: var(--transition);
}

.btn-primary:hover {
  background-color: var(--primary-hover) !important;
  border-color: var(--primary-hover) !important;
  transform: translateY(-2px);
  box-shadow: 0 4px 8px rgba(0, 123, 255, 0.3);
}

.btn-light {
  transition: all 0.3s ease;
}

.btn-light:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
}

/* 导航栏样式 */
.navbar {
  transition: all 0.3s ease;
  z-index: 1000;
}

.navbar-brand {
  font-weight: bold;
}

.nav-link {
  font-weight: 500;
  transition: all 0.3s ease;
  position: relative;
  padding: 0.75rem 1rem;
}

.nav-link:hover {
  color: var(--primary-color) !important;
  transform: translateY(-2px);
}

.nav-link:hover::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 60%;
  height: 2px;
  background-color: var(--primary-color);
  border-radius: var(--border-radius-sm);
  animation: hoverLine 0.3s ease forwards;
}

@keyframes hoverLine {
  from {
    width: 0;
    opacity: 0;
  }
  to {
    width: 60%;
    opacity: 1;
  }
}

.nav-link.active {
  color: var(--primary-color) !important;
  font-weight: bold;
  position: relative;
}

.nav-link.active::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 80%;
  height: 2px;
  background-color: var(--primary-color);
  border-radius: var(--border-radius-sm);
}

.nav-link.active.dropdown-toggle::after {
  width: 60%;
}

/* 下拉菜单样式 */
.dropdown-menu {
  transition: all 0.3s ease;
  z-index: 1050;
  border: none;
  border-radius: var(--border-radius-md);
  box-shadow: var(--shadow-lg);
  padding: 0.5rem 0;
  min-width: 180px;
}

.dropdown-item {
  padding: 0.75rem 1.5rem;
  transition: all 0.3s ease;
  border-bottom: 1px solid rgba(0, 0, 0, 0.05);
}

.dropdown-item:last-child {
  border-bottom: none;
}

.dropdown-item:hover {
  background-color: var(--light-color);
  color: var(--primary-color);
  transform: translateX(5px);
}

.dropdown-item.active {
  background-color: var(--primary-color);
  color: white;
}

/* 确保下拉菜单在移动设备上正常显示 */
@media (max-width: 768px) {
  .dropdown-menu {
    position: static;
    float: none;
    box-shadow: none;
    border: 1px solid var(--border-color);
    margin-top: 0.5rem;
    margin-bottom: 0.5rem;
  }
  
  .dropdown-item {
    padding: 0.5rem 1rem;
  }
}

/* 英雄区域样式 */
.hero-section {
  position: relative;
}

.hero-section::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(0, 0, 0, 0.5);
  z-index: 1;
}

.hero-section .container {
  position: relative;
  z-index: 2;
}

/* 响应式设计 */
@media (max-width: 768px) {
  .py-12 {
    padding-top: 80px;
    padding-bottom: 80px;
  }
  
  .mb-10 {
    margin-bottom: 60px;
  }
  
  .mb-6 {
    margin-bottom: 40px;
  }
  
  .hero-section {
    padding: 120px 0 80px;
  }
  
  .hero-section h1 {
    font-size: 2rem;
  }
  
  .navbar-nav {
    margin-top: 10px;
  }
  
  .navbar-nav .nav-item {
    margin-bottom: 10px;
  }
  
  .navbar-brand {
    margin-bottom: 10px;
  }
}

/* 表单样式 */
.form-control {
  border-radius: 0.375rem;
  transition: border-color 0.15s ease-in-out, box-shadow 0.15s ease-in-out;
}

.form-control:focus {
  border-color: #007bff;
  box-shadow: 0 0 0 0.25rem rgba(0, 123, 255, 0.25);
}

/* 页脚样式 */
.footer-section {
  background-color: #343a40;
  color: white;
}

.footer-section a {
  color: #adb5bd;
  transition: color 0.3s ease;
}

.footer-section a:hover {
  color: white;
  text-decoration: none;
}

/* 滚动条样式 */
::-webkit-scrollbar {
  width: 8px;
}

::-webkit-scrollbar-track {
  background: #f1f1f1;
}

::-webkit-scrollbar-thumb {
  background: #007bff;
  border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
  background: #0069d9;
}

/* 轮播图样式 */
.carousel-section {
  position: relative;
  margin-top: 76px;
}

.carousel-item {
  position: relative;
}

.carousel-item::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(0, 0, 0, 0.3);
  z-index: 1;
}

.carousel-item img {
  position: relative;
  z-index: 0;
}

.carousel-caption {
  position: relative;
  z-index: 2;
}

/* 加载动画样式 */
.loading-overlay {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-color: rgba(255, 255, 255, 0.9);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 9999;
  transition: opacity 0.3s ease;
}

.loading-spinner {
  width: 50px;
  height: 50px;
  border: 5px solid #f3f3f3;
  border-top: 5px solid #007bff;
  border-radius: 50%;
  animation: spin 1s linear infinite;
}

@keyframes spin {
  0% { transform: rotate(0deg); }
  100% { transform: rotate(360deg); }
}

/* 下拉菜单样式 */
.dropdown-menu {
  border-radius: 0.5rem;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
  transition: all 0.3s ease;
  border: none;
  padding: 0.5rem 0;
  animation: dropdownFadeIn 0.3s ease forwards;
}

@keyframes dropdownFadeIn {
  from {
    opacity: 0;
    transform: translateY(-10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.dropdown-item {
  transition: all 0.2s ease;
  padding: 0.75rem 1.5rem;
  border-left: 3px solid transparent;
}

.dropdown-item:hover {
  background-color: #f8f9fa;
  transform: translateX(5px);
  border-left-color: #007bff;
  color: #007bff;
}

.dropdown-item.active {
  background-color: #e3f2fd;
  color: #007bff;
  border-left-color: #007bff;
}

.dropdown-toggle::after {
  transition: transform 0.3s ease;
}

.dropdown-toggle.show::after {
  transform: rotate(180deg);
}

/* 动画效果 */
@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes fadeInLeft {
  from {
    opacity: 0;
    transform: translateX(-30px);
  }
  to {
    opacity: 1;
    transform: translateX(0);
  }
}

@keyframes fadeInRight {
  from {
    opacity: 0;
    transform: translateX(30px);
  }
  to {
    opacity: 1;
    transform: translateX(0);
  }
}

@keyframes scaleIn {
  from {
    opacity: 0;
    transform: scale(0.9);
  }
  to {
    opacity: 1;
    transform: scale(1);
  }
}

/* 滚动动画类 */
.fade-in {
  opacity: 0;
  transform: translateY(20px);
  transition: all 0.6s ease;
}

.fade-in.active {
  opacity: 1;
  transform: translateY(0);
}

.fade-in-left {
  opacity: 0;
  transform: translateX(-30px);
  transition: all 0.6s ease;
}

.fade-in-left.active {
  opacity: 1;
  transform: translateX(0);
}

.fade-in-right {
  opacity: 0;
  transform: translateX(30px);
  transition: all 0.6s ease;
}

.fade-in-right.active {
  opacity: 1;
  transform: translateX(0);
}

.scale-in {
  opacity: 0;
  transform: scale(0.9);
  transition: all 0.6s ease;
}

.scale-in.active {
  opacity: 1;
  transform: scale(1);
}

/* 页面元素动画 */
.feature-card,
.service-card,
.store-card,
.equipment-card,
.news-card,
.franchise-card,
.consultation-card {
  animation: fadeIn 0.6s ease forwards;
  opacity: 0;
}

.feature-card:nth-child(1),
.service-card:nth-child(1),
.store-card:nth-child(1),
.equipment-card:nth-child(1),
.news-card:nth-child(1),
.franchise-card:nth-child(1),
.consultation-card:nth-child(1) {
  animation-delay: 0.1s;
}

.feature-card:nth-child(2),
.service-card:nth-child(2),
.store-card:nth-child(2),
.equipment-card:nth-child(2),
.news-card:nth-child(2),
.franchise-card:nth-child(2),
.consultation-card:nth-child(2) {
  animation-delay: 0.2s;
}

.feature-card:nth-child(3),
.service-card:nth-child(3),
.store-card:nth-child(3),
.equipment-card:nth-child(3),
.news-card:nth-child(3),
.franchise-card:nth-child(3),
.consultation-card:nth-child(3) {
  animation-delay: 0.3s;
}

.service-card:nth-child(4),
.equipment-card:nth-child(4),
.news-card:nth-child(4),
.franchise-card:nth-child(4) {
  animation-delay: 0.4s;
}

/* 标题动画 */
h1, h2, h3, h4, h5, h6 {
  opacity: 0;
  transform: translateY(-10px);
  animation: fadeIn 0.4s ease forwards;
}

/* 按钮动画 */
.btn {
  position: relative;
  overflow: hidden;
}

.btn::before {
  content: '';
  position: absolute;
  top: 50%;
  left: 50%;
  width: 0;
  height: 0;
  background-color: rgba(255, 255, 255, 0.2);
  border-radius: 50%;
  transform: translate(-50%, -50%);
  transition: all 0.6s ease;
}

.btn:hover::before {
  width: 300px;
  height: 300px;
}

/* 图片悬停动画 */
img {
  transition: all 0.3s ease;
}

img:hover {
  transform: scale(1.05);
}

/* 表单元素动画 */
.form-control {
  transition: all 0.3s ease;
}

.form-control:focus {
  transform: translateY(-2px);
  box-shadow: 0 0 0 0.25rem rgba(0, 123, 255, 0.25), 0 4px 12px rgba(0, 123, 255, 0.15);
}

/* 响应式导航栏样式 */
@media (max-width: 992px) {
  .navbar-collapse {
    background-color: var(--light-color);
    box-shadow: var(--shadow-md);
    border-radius: var(--border-radius-lg);
    padding: 1rem;
    margin-top: 0.5rem;
    animation: navbarFadeIn 0.3s ease forwards;
  }
  
  @keyframes navbarFadeIn {
    from {
      opacity: 0;
      transform: translateY(-10px);
    }
    to {
      opacity: 1;
      transform: translateY(0);
    }
  }
  
  .navbar-nav .nav-item {
    margin-bottom: 0.5rem;
  }
  
  .nav-link {
    padding: 0.75rem 1rem;
    border-radius: var(--border-radius-md);
  }
  
  .nav-link:hover {
    background-color: rgba(0, 123, 255, 0.1);
    transform: none;
  }
  
  .nav-link:hover::after {
    display: none;
  }
  
  .nav-link.active::after {
    display: none;
  }
  
  .nav-link.active {
    background-color: rgba(0, 123, 255, 0.1);
    border-left: 3px solid var(--primary-color);
  }
  
  .dropdown-menu {
    margin-left: 1rem;
    margin-top: 0.25rem;
  }
  
  .dropdown-item {
    padding: 0.5rem 1.25rem;
  }
  
  .navbar-brand {
    margin-bottom: 0;
  }
}

.store-card:nth-child(2) {
  animation-delay: 0.2s;
}

.store-card:nth-child(3) {
  animation-delay: 0.3s;
}

/* 响应式图片 */
img {
  max-width: 100%;
  height: auto;
}

/* 标题样式 */
h1, h2, h3, h4, h5, h6 {
  font-weight: bold;
  margin-bottom: 1rem;
}

/* 响应式调整 */
@media (max-width: 768px) {
  .carousel-section {
    margin-top: 60px;
  }
  
  .carousel-item img {
    height: 300px !important;
  }
  
  .carousel-caption h1 {
    font-size: 1.5rem !important;
  }
  
  .carousel-caption p {
    font-size: 1rem !important;
  }
}

/* 段落样式 */
p {
  line-height: 1.6;
  margin-bottom: 1rem;
}

/* 页面加载动画 */
.loading-overlay {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-color: rgba(255, 255, 255, 0.9);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 9999;
  transition: opacity 0.3s ease, visibility 0.3s ease;
}

.loading-spinner {
  width: 50px;
  height: 50px;
  border: 5px solid #f3f3f3;
  border-top: 5px solid #007bff;
  border-radius: 50%;
  animation: spin 1s linear infinite;
}

@keyframes spin {
  0% { transform: rotate(0deg); }
  100% { transform: rotate(360deg); }
}

body.loaded .loading-overlay {
  opacity: 0;
  visibility: hidden;
}

/* 图片加载状态 */
.img-loading {
  opacity: 0.5;
  transition: opacity 0.3s ease;
}

.img-loaded {
  opacity: 1;
  transition: opacity 0.3s ease;
}

.img-error {
  opacity: 0.8;
  background-color: #f8f9fa;
  display: flex;
  align-items: center;
  justify-content: center;
  color: #6c757d;
}

/* 按钮加载状态 */
.btn-loading {
  position: relative;
  pointer-events: none;
}

.btn-loading::after {
  content: '';
  position: absolute;
  top: 50%;
  left: 50%;
  width: 16px;
  height: 16px;
  margin: -8px 0 0 -8px;
  border: 2px solid #fff;
  border-top: 2px solid transparent;
  border-radius: 50%;
  animation: spin 1s linear infinite;
}
/* 容器样式 */
.container {
  max-width: 1200px;
}

/* 阴影效果 */
.shadow-sm {
  box-shadow: 0 0.125rem 0.25rem rgba(0, 0, 0, 0.075);
}

.shadow-md {
  box-shadow: 0 0.5rem 1rem rgba(0, 0, 0, 0.15);
}

/* 圆角样式 */
.rounded {
  border-radius: 0.25rem;
}

.rounded-lg {
  border-radius: 0.5rem;
}

.rounded-circle {
  border-radius: 50%;
}

/* 文本颜色 */
.text-muted {
  color: #6c757d;
}

.text-white {
  color: #fff;
}

/* 背景颜色 */
.bg-white {
  background-color: #fff;
}

.bg-light {
  background-color: #f8f9fa;
}

.bg-dark {
  background-color: #343a40;
}

/* 弹性布局 */
.d-flex {
  display: flex;
}

.align-items-center {
  align-items: center;
}

.justify-content-center {
  justify-content: center;
}

.justify-content-between {
  justify-content: space-between;
}

.flex-column {
  flex-direction: column;
}

/* 网格布局 */
.row {
  display: flex;
  flex-wrap: wrap;
  margin-right: -15px;
  margin-left: -15px;
}

.col-lg-1, .col-lg-2, .col-lg-3, .col-lg-4, .col-lg-5, .col-lg-6, .col-lg-7, .col-lg-8, .col-lg-9, .col-lg-10, .col-lg-11, .col-lg-12,
.col-md-1, .col-md-2, .col-md-3, .col-md-4, .col-md-5, .col-md-6, .col-md-7, .col-md-8, .col-md-9, .col-md-10, .col-md-11, .col-md-12 {
  position: relative;
  width: 100%;
  padding-right: 15px;
  padding-left: 15px;
}

@media (min-width: 768px) {
  .col-md-6 {
    flex: 0 0 50%;
    max-width: 50%;
  }
}

@media (min-width: 992px) {
  .col-lg-3 {
    flex: 0 0 25%;
    max-width: 25%;
  }
  
  .col-lg-4 {
    flex: 0 0 33.333333%;
    max-width: 33.333333%;
  }
  
  .col-lg-6 {
    flex: 0 0 50%;
    max-width: 50%;
  }
  
  .col-lg-8 {
    flex: 0 0 66.666667%;
    max-width: 66.666667%;
  }
}

/* 文本对齐 */
.text-center {
  text-align: center;
}

.text-left {
  text-align: left;
}

.text-right {
  text-align: right;
}

/* 间距辅助类 */
.mt-1 { margin-top: 0.25rem; }
.mt-2 { margin-top: 0.5rem; }
.mt-3 { margin-top: 1rem; }
.mt-4 { margin-top: 1.5rem; }
.mt-5 { margin-top: 3rem; }

.mb-1 { margin-bottom: 0.25rem; }
.mb-2 { margin-bottom: 0.5rem; }
.mb-3 { margin-bottom: 1rem; }
.mb-4 { margin-bottom: 1.5rem; }
.mb-5 { margin-bottom: 3rem; }

.ml-1 { margin-left: 0.25rem; }
.ml-2 { margin-left: 0.5rem; }
.ml-3 { margin-left: 1rem; }
.ml-4 { margin-left: 1.5rem; }
.ml-5 { margin-left: 3rem; }

.mr-1 { margin-right: 0.25rem; }
.mr-2 { margin-right: 0.5rem; }
.mr-3 { margin-right: 1rem; }
.mr-4 { margin-right: 1.5rem; }
.mr-5 { margin-right: 3rem; }

.p-1 { padding: 0.25rem; }
.p-2 { padding: 0.5rem; }
.p-3 { padding: 1rem; }
.p-4 { padding: 1.5rem; }
.p-5 { padding: 3rem; }

.py-1 { padding-top: 0.25rem; padding-bottom: 0.25rem; }
.py-2 { padding-top: 0.5rem; padding-bottom: 0.5rem; }
.py-3 { padding-top: 1rem; padding-bottom: 1rem; }
.py-4 { padding-top: 1.5rem; padding-bottom: 1.5rem; }
.py-5 { padding-top: 3rem; padding-bottom: 3rem; }

.px-1 { padding-left: 0.25rem; padding-right: 0.25rem; }
.px-2 { padding-left: 0.5rem; padding-right: 0.5rem; }
.px-3 { padding-left: 1rem; padding-right: 1rem; }
.px-4 { padding-left: 1.5rem; padding-right: 1.5rem; }
.px-5 { padding-left: 3rem; padding-right: 3rem; }

/* 显示辅助类 */
.d-none { display: none; }
.d-block { display: block; }
.d-inline { display: inline; }
.d-inline-block { display: inline-block; }

/* 响应式显示 */
@media (max-width: 768px) {
  .d-md-none { display: none; }
  .d-md-block { display: block; }
}

@media (min-width: 768px) {
  .d-md-none { display: none; }
  .d-md-block { display: block; }
}

/* 定位辅助类 */
.position-relative { position: relative; }
.position-absolute { position: absolute; }
.position-fixed { position: fixed; }
.position-static { position: static; }

/* 溢出辅助类 */
.overflow-hidden { overflow: hidden; }
.overflow-auto { overflow: auto; }

/* 文本截断 */
.text-truncate {
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

/* 字体大小 */
.fs-1 { font-size: 2.5rem; }
.fs-2 { font-size: 2rem; }
.fs-3 { font-size: 1.75rem; }
.fs-4 { font-size: 1.5rem; }
.fs-5 { font-size: 1.25rem; }
.fs-6 { font-size: 1rem; }

/* 字体粗细 */
.fw-light { font-weight: 300; }
.fw-normal { font-weight: 400; }
.fw-medium { font-weight: 500; }
.fw-bold { font-weight: 700; }

/* 行高 */
.lh-1 { line-height: 1; }
.lh-sm { line-height: 1.25; }
.lh-base { line-height: 1.5; }
.lh-lg { line-height: 2; }

/* 文本转换 */
.text-lowercase { text-transform: lowercase; }
.text-uppercase { text-transform: uppercase; }
.text-capitalize { text-transform: capitalize; }

/* 文本装饰 */
.text-decoration-none { text-decoration: none; }
.text-decoration-underline { text-decoration: underline; }
.text-decoration-line-through { text-decoration: line-through; }

/* 列表样式 */
.list-unstyled {
  list-style: none;
  padding-left: 0;
}

/* 表格样式 */
.table {
  width: 100%;
  margin-bottom: 1rem;
  color: #212529;
  border-collapse: collapse;
}

.table th,
.table td {
  padding: 0.75rem;
  vertical-align: top;
  border-top: 1px solid #dee2e6;
}

.table thead th {
  vertical-align: bottom;
  border-bottom: 2px solid #dee2e6;
}

.table tbody + tbody {
  border-top: 2px solid #dee2e6;
}

/* 表单控件 */
.form-control {
  display: block;
  width: 100%;
  padding: 0.375rem 0.75rem;
  font-size: 1rem;
  font-weight: 400;
  line-height: 1.5;
  color: #495057;
  background-color: #fff;
  background-clip: padding-box;
  border: 1px solid #ced4da;
  border-radius: 0.25rem;
  transition: border-color 0.15s ease-in-out, box-shadow 0.15s ease-in-out;
}

.form-control:focus {
  color: #495057;
  background-color: #fff;
  border-color: #80bdff;
  outline: 0;
  box-shadow: 0 0 0 0.2rem rgba(0, 123, 255, 0.25);
}

.form-label {
  display: inline-block;
  margin-bottom: 0.5rem;
}

/* 按钮基础样式 */
.btn {
  display: inline-block;
  font-weight: 400;
  line-height: 1.5;
  color: #212529;
  text-align: center;
  text-decoration: none;
  vertical-align: middle;
  cursor: pointer;
  -webkit-user-select: none;
  -moz-user-select: none;
  -ms-user-select: none;
  user-select: none;
  background-color: transparent;
  border: 1px solid transparent;
  padding: 0.375rem 0.75rem;
  font-size: 1rem;
  border-radius: 0.25rem;
  transition: color 0.15s ease-in-out, background-color 0.15s ease-in-out, border-color 0.15s ease-in-out, box-shadow 0.15s ease-in-out;
}

.btn:hover {
  color: #212529;
  text-decoration: none;
}

.btn:focus {
  outline: 0;
  box-shadow: 0 0 0 0.2rem rgba(0, 123, 255, 0.25);
}

/* 按钮大小 */
.btn-sm {
  padding: 0.25rem 0.5rem;
  font-size: 0.875rem;
  border-radius: 0.2rem;
}

.btn-lg {
  padding: 0.5rem 1rem;
  font-size: 1.25rem;
  border-radius: 0.3rem;
}

/* 按钮块级 */
.btn-block {
  display: block;
  width: 100%;
}

/* 响应式工具类 */
@media (max-width: 575.98px) {
  .d-xs-block { display: block !important; }
  .d-xs-none { display: none !important; }
}

@media (min-width: 576px) and (max-width: 767.98px) {
  .d-sm-block { display: block !important; }
  .d-sm-none { display: none !important; }
}

@media (min-width: 768px) and (max-width: 991.98px) {
  .d-md-block { display: block !important; }
  .d-md-none { display: none !important; }
}

@media (min-width: 992px) and (max-width: 1199.98px) {
  .d-lg-block { display: block !important; }
  .d-lg-none { display: none !important; }
}

@media (min-width: 1200px) {
  .d-xl-block { display: block !important; }
  .d-xl-none { display: none !important; }
}

/* 打印样式 */
@media print {
  * {
    color: #000 !important;
    text-shadow: none !important;
    background: transparent !important;
    box-shadow: none !important;
  }
  
  a,
  a:visited {
    text-decoration: underline;
  }
  
  a[href]:after {
    content: " (" attr(href) ")";
  }
  
  abbr[title]:after {
    content: " (" attr(title) ")";
  }
  
  a[href^="#"]:after,
  a[href^="javascript:"]:after {
    content: "";
  }
  
  pre,
  blockquote {
    border: 1px solid #999;
    page-break-inside: avoid;
  }
  
  thead {
    display: table-header-group;
  }
  
  tr,
  img {
    page-break-inside: avoid;
  }
  
  img {
    max-width: 100% !important;
  }
  
  p,
  h2,
  h3 {
    orphans: 3;
    widows: 3;
  }
  
  h2,
  h3 {
    page-break-after: avoid;
  }
}

/* 无障碍支持 */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.sr-only-focusable:active,
.sr-only-focusable:focus {
  position: static;
  width: auto;
  height: auto;
  padding: 0;
  margin: 0;
  overflow: visible;
  clip: auto;
  white-space: normal;
}

/* 焦点样式 */
.focus {
  outline: 2px solid #007bff;
  outline-offset: 2px;
}

/* 选择文本样式 */
::selection {
  background-color: #007bff;
  color: #fff;
}

::-moz-selection {
  background-color: #007bff;
  color: #fff;
}