/* 上海犇多多信息科技有限公司 - 公共样式 */
:root {
  --primary: #E65100;
  --primary-light: #FF8A50;
  --primary-dark: #BF360C;
  --accent: #D84315;
  --bg: #FFFBF7;
  --bg-section: #FFF5EE;
  --text: #2C1810;
  --text-secondary: #6B5B54;
  --text-light: #9E8E87;
  --border: #F0E0D6;
  --white: #FFFFFF;
  --shadow: 0 4px 24px rgba(230, 81, 0, 0.08);
  --shadow-lg: 0 8px 40px rgba(230, 81, 0, 0.12);
  --radius: 8px;
  --radius-lg: 16px;
  --transition: 0.3s ease;
}

*, *::before, *::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.7;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
}

a {
  color: var(--primary);
  text-decoration: none;
  transition: color var(--transition);
}

a:hover {
  color: var(--accent);
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
}

/* 区块标题 */
.section-header {
  text-align: center;
  margin-bottom: 56px;
}

.section-tag {
  display: inline-block;
  font-size: 13px;
  color: var(--primary);
  letter-spacing: 4px;
  margin-bottom: 12px;
  font-weight: 500;
}

.section-title {
  font-size: 32px;
  font-weight: 600;
  color: var(--text);
  margin-bottom: 16px;
  letter-spacing: 2px;
}

.section-desc {
  font-size: 16px;
  color: var(--text-secondary);
  max-width: 600px;
  margin: 0 auto;
  line-height: 1.8;
}

/* 按钮 */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 14px 36px;
  font-size: 15px;
  font-weight: 500;
  border-radius: var(--radius);
  border: none;
  cursor: pointer;
  transition: all var(--transition);
  letter-spacing: 1px;
}

.btn-primary {
  background: linear-gradient(135deg, var(--primary) 0%, var(--accent) 100%);
  color: var(--white);
  box-shadow: 0 4px 16px rgba(230, 81, 0, 0.3);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 24px rgba(230, 81, 0, 0.4);
  color: var(--white);
}

.btn-primary:disabled {
  opacity: 0.7;
  cursor: not-allowed;
  transform: none;
  box-shadow: none;
}

.btn-outline {
  background: transparent;
  color: var(--primary);
  border: 1.5px solid var(--primary);
}

.btn-outline:hover {
  background: var(--primary);
  color: var(--white);
}

/* 页脚 */
.footer {
  background: #1A1208;
  color: rgba(255, 255, 255, 0.7);
  padding: 48px 0 24px;
}

.footer-inner {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  flex-wrap: wrap;
  gap: 32px;
  margin-bottom: 32px;
}

.footer-brand .logo-text {
  font-size: 20px;
  font-weight: 600;
  color: var(--white);
  margin-bottom: 8px;
}

.footer-brand p {
  font-size: 14px;
  line-height: 1.8;
}

.footer-links h4 {
  color: var(--white);
  font-size: 15px;
  margin-bottom: 16px;
  font-weight: 500;
}

.footer-links ul {
  list-style: none;
}

.footer-links li {
  margin-bottom: 8px;
}

.footer-links a {
  color: rgba(255, 255, 255, 0.6);
  font-size: 14px;
}

.footer-links a:hover {
  color: var(--primary-light);
}

.footer-bottom {
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  padding-top: 24px;
  text-align: center;
  font-size: 13px;
  color: rgba(255, 255, 255, 0.4);
}

/* 回到顶部 */
.back-to-top {
  position: fixed;
  bottom: 32px;
  right: 32px;
  width: 44px;
  height: 44px;
  background: var(--primary);
  color: var(--white);
  border: none;
  border-radius: 50%;
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transition: all var(--transition);
  z-index: 99;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 18px;
  box-shadow: var(--shadow);
}

.back-to-top.visible {
  opacity: 1;
  visibility: visible;
}

.back-to-top:hover {
  background: var(--accent);
  transform: translateY(-2px);
}

/* 动画 */
.fade-in {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

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