/* ========================================
   仁安堂中医馆 · 设计系统样式
   配色：#8C3130 暗红 / #C8A97E 鎏金 / #2D5543 墨绿
   中性：#F8F3EB 米白 / #7A7265 灰褐 / #2B2622 炭黑
   ======================================== */

/* --- 基础变量 --- */
:root {
  --color-primary: #8C3130;
  --color-primary-dark: #6E2423;
  --color-primary-light: #A8403F;
  --color-gold: #C8A97E;
  --color-gold-light: #D4BB9A;
  --color-gold-dark: #B08E60;
  --color-green: #2D5543;
  --color-green-light: #3A6B54;
  --color-green-dark: #1F3D30;
  --color-bg: #F8F3EB;
  --color-bg-dark: #EDE4D3;
  --color-gray: #7A7265;
  --color-gray-light: #9A9487;
  --color-text: #2B2622;
  --color-text-light: #5A5248;
  --font-title: 'Inter', 'Noto Sans SC', sans-serif;
  --font-body: 'Inter', 'Noto Sans SC', sans-serif;
  --radius-btn: 6px;
  --radius-card: 8px;
  --shadow-card: 0 4px 20px rgba(43,38,34,0.08);
  --shadow-card-hover: 0 8px 32px rgba(43,38,34,0.14);
  --transition-base: 280ms ease;
  --transition-slow: 330ms ease;
}

/* --- 全局重置 --- */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: var(--font-body);
  font-weight: 400;
  font-size: 16px;
  line-height: 1.65;
  color: var(--color-text);
  background-color: var(--color-bg);
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

/* --- 标题系统 --- */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-title);
  font-weight: 700;
  letter-spacing: -0.3px;
  color: var(--color-text);
}

h1 { font-size: 44px; line-height: 1.2; }
h2 { font-size: 36px; line-height: 1.25; }
h3 { font-size: 28px; line-height: 1.3; }
h4 { font-size: 22px; line-height: 1.35; }

@media (max-width: 768px) {
  h1 { font-size: 32px; }
  h2 { font-size: 26px; }
  h3 { font-size: 22px; }
  h4 { font-size: 18px; }
}

@media (max-width: 360px) {
  h1 { font-size: 26px; }
  h2 { font-size: 22px; }
  h3 { font-size: 18px; }
}

/* --- 段落与文本 --- */
p {
  margin-bottom: 1em;
  color: var(--color-text-light);
}

.text-gold { color: var(--color-gold); }
.text-primary { color: var(--color-primary); }
.text-green { color: var(--color-green); }
.text-gray { color: var(--color-gray); }

/* --- 中式装饰线 --- */
.deco-line {
  display: block;
  width: 48px;
  height: 2px;
  background: var(--color-gold);
  margin: 12px auto 0;
}

.deco-line-left {
  display: block;
  width: 48px;
  height: 2px;
  background: var(--color-gold);
  margin: 12px 0 0;
}

/* --- 按钮 --- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 28px;
  font-family: var(--font-title);
  font-size: 15px;
  font-weight: 600;
  letter-spacing: 0.5px;
  border-radius: var(--radius-btn);
  border: none;
  cursor: pointer;
  transition: transform var(--transition-base), opacity var(--transition-base), background-color var(--transition-base);
  text-decoration: none;
  line-height: 1;
}

.btn:hover {
  transform: translateY(-1px);
}

.btn-primary {
  background-color: var(--color-primary);
  color: #fff;
}

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

.btn-gold {
  background-color: var(--color-gold);
  color: var(--color-text);
}

.btn-gold:hover {
  background-color: var(--color-gold-dark);
}

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

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

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

.btn-outline-gold:hover {
  background-color: var(--color-gold);
  color: var(--color-text);
}

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

.btn-sm {
  padding: 8px 20px;
  font-size: 13px;
}

/* --- 卡片 --- */
.card {
  background: #fff;
  border-radius: var(--radius-card);
  box-shadow: var(--shadow-card);
  padding: 28px;
  transition: transform var(--transition-base), box-shadow var(--transition-base);
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-card-hover);
}

.card-flat {
  background: #fff;
  border-radius: var(--radius-card);
  padding: 28px;
  border: 1px solid rgba(200,169,126,0.15);
  transition: transform var(--transition-base), border-color var(--transition-base);
}

.card-flat:hover {
  transform: translateY(-2px);
  border-color: rgba(200,169,126,0.4);
}

/* --- 区块标题 --- */
.section-title {
  text-align: center;
  margin-bottom: 48px;
}

.section-title h2 {
  margin-bottom: 8px;
}

.section-title .subtitle {
  font-size: 15px;
  color: var(--color-gray);
  letter-spacing: 2px;
}

.section-title .deco-line {
  margin-top: 16px;
}

/* --- 导航栏 --- */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background: rgba(248,243,235,0.92);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid rgba(200,169,126,0.12);
  transition: background-color var(--transition-base), box-shadow var(--transition-base);
}

.navbar.scrolled {
  background: rgba(248,243,235,0.97);
  box-shadow: 0 2px 16px rgba(43,38,34,0.08);
}

.navbar-inner {
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 16px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 72px;
}

@media (min-width: 768px) {
  .navbar-inner { padding: 0 32px; }
}

.navbar-brand {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  color: var(--color-primary);
  font-weight: 700;
  font-size: 20px;
  letter-spacing: 2px;
}

.navbar-brand .brand-icon {
  width: 36px;
  height: 36px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 4px;
  background: var(--color-primary);
  color: #fff;
  font-size: 18px;
  font-weight: 700;
}

.navbar-nav {
  display: none;
  list-style: none;
  gap: 32px;
}

@media (min-width: 768px) {
  .navbar-nav {
    display: flex;
  }
}

.navbar-nav a {
  text-decoration: none;
  font-size: 14px;
  font-weight: 500;
  color: var(--color-text);
  letter-spacing: 1px;
  transition: color var(--transition-base);
  position: relative;
}

.navbar-nav a:hover,
.navbar-nav a.active {
  color: var(--color-primary);
}

.navbar-nav a.active::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 0;
  right: 0;
  height: 2px;
  background: var(--color-primary);
  border-radius: 1px;
}

.navbar-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border: none;
  background: transparent;
  cursor: pointer;
  color: var(--color-text);
  font-size: 22px;
}

@media (min-width: 768px) {
  .navbar-toggle { display: none; }
}

/* --- 移动端导航菜单 --- */
.mobile-menu {
  position: fixed;
  top: 72px;
  left: 0;
  right: 0;
  background: rgba(248,243,235,0.98);
  backdrop-filter: blur(12px);
  z-index: 999;
  padding: 16px 24px;
  border-bottom: 1px solid rgba(200,169,126,0.15);
  transform: translateY(-100%);
  opacity: 0;
  transition: transform var(--transition-base), opacity var(--transition-base);
  pointer-events: none;
}

.mobile-menu.open {
  transform: translateY(0);
  opacity: 1;
  pointer-events: all;
}

.mobile-menu a {
  display: block;
  padding: 12px 0;
  font-size: 15px;
  font-weight: 500;
  color: var(--color-text);
  text-decoration: none;
  letter-spacing: 1px;
  border-bottom: 1px solid rgba(200,169,126,0.08);
  transition: color var(--transition-base);
}

.mobile-menu a:hover,
.mobile-menu a.active {
  color: var(--color-primary);
}

/* --- Hero Banner --- */
.hero {
  min-height: 540px;
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
  overflow: hidden;
  background: var(--color-text);
}

@media (min-width: 768px) {
  .hero { min-height: 600px; }
}

@media (min-width: 1200px) {
  .hero { min-height: 680px; }
}

.hero-bg {
  position: absolute;
  inset: 0;
  background-size: cover;
  background-position: center;
  opacity: 0.35;
}

.hero-overlay {
  position: absolute;
  inset: 0;
  background: linear-gradient(180deg, rgba(43,38,34,0.6) 0%, rgba(43,38,34,0.85) 100%);
}

.hero-content {
  position: relative;
  z-index: 2;
  text-align: center;
  max-width: 720px;
  padding: 0 24px;
}

.hero-content h1 {
  color: #fff;
  margin-bottom: 16px;
}

.hero-content .hero-gold {
  color: var(--color-gold);
  font-size: 18px;
  letter-spacing: 6px;
  margin-bottom: 24px;
  font-weight: 500;
}

.hero-content p {
  color: rgba(255,255,255,0.8);
  font-size: 17px;
  margin-bottom: 32px;
}

.hero-content .btn-group {
  display: flex;
  gap: 16px;
  justify-content: center;
  flex-wrap: wrap;
}

/* --- 中式纹饰背景 --- */
.pattern-bg {
  position: relative;
}

.pattern-bg::before {
  content: '';
  position: absolute;
  inset: 0;
  opacity: 0.03;
  background-image: url("data:image/svg+xml,%3Csvg width='60' height='60' viewBox='0 0 60 60' xmlns='http://www.w3.org/2000/svg'%3E%3Cpath d='M30 0L60 30L30 60L0 30Z' fill='%23C8A97E' fill-opacity='1'/%3E%3C/svg%3E");
  background-size: 60px 60px;
  pointer-events: none;
}

/* --- 滚动渐入动画 --- */
.fade-in {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity var(--transition-slow), transform var(--transition-slow);
}

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

.fade-in-left {
  opacity: 0;
  transform: translateX(-24px);
  transition: opacity var(--transition-slow), transform var(--transition-slow);
}

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

.fade-in-right {
  opacity: 0;
  transform: translateX(24px);
  transition: opacity var(--transition-slow), transform var(--transition-slow);
}

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

/* --- 页脚 --- */
.footer {
  background: var(--color-text);
  color: rgba(255,255,255,0.7);
  padding-top: 48px;
  padding-bottom: 24px;
}

.footer-inner {
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 16px;
}

@media (min-width: 768px) {
  .footer-inner { padding: 0 32px; }
}

.footer-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 32px;
  margin-bottom: 40px;
}

@media (min-width: 768px) {
  .footer-grid {
    grid-template-columns: 2fr 1fr 1fr 1fr;
    gap: 40px;
  }
}

.footer h4 {
  color: #fff;
  font-size: 16px;
  margin-bottom: 16px;
  letter-spacing: 1px;
}

.footer-brand {
  font-size: 20px;
  font-weight: 700;
  color: var(--color-gold);
  letter-spacing: 2px;
  margin-bottom: 12px;
}

.footer p {
  color: rgba(255,255,255,0.6);
  font-size: 14px;
  margin-bottom: 8px;
}

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

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

.footer-links a {
  color: rgba(255,255,255,0.6);
  text-decoration: none;
  font-size: 14px;
  transition: color var(--transition-base);
}

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

.footer-bottom {
  border-top: 1px solid rgba(255,255,255,0.08);
  padding-top: 20px;
  text-align: center;
  font-size: 13px;
  color: rgba(255,255,255,0.4);
}

/* --- 悬浮客服 --- */
.float-service {
  position: fixed;
  right: 16px;
  top: 50%;
  transform: translateY(-50%);
  z-index: 900;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

@media (max-width: 360px) {
  .float-service { right: 8px; }
}

.float-item {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 48px;
  height: 48px;
  border-radius: 6px;
  background: var(--color-primary);
  color: #fff;
  cursor: pointer;
  transition: transform var(--transition-base), background-color var(--transition-base);
  position: relative;
  font-size: 20px;
  text-decoration: none;
}

.float-item:hover {
  background: var(--color-primary-dark);
  transform: scale(1.08);
}

.float-item .float-tooltip {
  position: absolute;
  right: 56px;
  top: 50%;
  transform: translateY(-50%);
  background: var(--color-text);
  color: #fff;
  padding: 8px 14px;
  border-radius: 6px;
  font-size: 13px;
  white-space: nowrap;
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--transition-base);
}

.float-item:hover .float-tooltip {
  opacity: 1;
  pointer-events: all;
}

/* 微信二维码弹窗 */
.float-wechat-popup {
  position: absolute;
  right: 56px;
  top: 50%;
  transform: translateY(-50%);
  background: #fff;
  border-radius: 8px;
  box-shadow: 0 8px 32px rgba(43,38,34,0.18);
  padding: 16px;
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--transition-base);
  z-index: 910;
  width: 180px;
}

.float-wechat-popup.open {
  opacity: 1;
  pointer-events: all;
}

.float-wechat-popup h5 {
  font-size: 14px;
  color: var(--color-text);
  text-align: center;
  margin-bottom: 10px;
  font-weight: 600;
}

.float-wechat-popup .qr-placeholder {
  width: 148px;
  height: 148px;
  background: var(--color-bg);
  border: 1px solid rgba(200,169,126,0.2);
  border-radius: 4px;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-direction: column;
  gap: 6px;
  color: var(--color-gray);
  font-size: 12px;
}

.float-wechat-popup .qr-placeholder .qr-icon {
  font-size: 40px;
  color: var(--color-green);
}

/* --- 服务/项目网格 --- */
.service-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 24px;
}

@media (min-width: 768px) {
  .service-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 28px;
  }
}

@media (min-width: 1200px) {
  .service-grid {
    grid-template-columns: repeat(3, 1fr);
    gap: 32px;
  }
}

.service-card {
  background: #fff;
  border-radius: var(--radius-card);
  padding: 28px 24px;
  box-shadow: var(--shadow-card);
  transition: transform var(--transition-base), box-shadow var(--transition-base);
  text-align: center;
}

.service-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-card-hover);
}

.service-card .service-icon {
  width: 56px;
  height: 56px;
  margin: 0 auto 16px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 50%;
  background: rgba(140,49,48,0.08);
  color: var(--color-primary);
  font-size: 24px;
}

.service-card h4 {
  font-size: 18px;
  margin-bottom: 10px;
}

.service-card p {
  font-size: 14px;
  color: var(--color-gray);
  line-height: 1.6;
}

/* --- 医师卡片 --- */
.doctor-card {
  background: #fff;
  border-radius: var(--radius-card);
  padding: 24px;
  box-shadow: var(--shadow-card);
  transition: transform var(--transition-base), box-shadow var(--transition-base);
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
}

.doctor-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-card-hover);
}

.doctor-card .doctor-avatar {
  width: 88px;
  height: 88px;
  border-radius: 50%;
  background: var(--color-bg);
  border: 2px solid rgba(200,169,126,0.25);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-gold);
  font-size: 36px;
  margin-bottom: 16px;
}

.doctor-card .doctor-name {
  font-size: 18px;
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: 4px;
}

.doctor-card .doctor-title {
  font-size: 13px;
  color: var(--color-gold);
  letter-spacing: 1px;
  margin-bottom: 12px;
}

.doctor-card .doctor-desc {
  font-size: 14px;
  color: var(--color-gray);
  line-height: 1.6;
}

/* --- 知识文章卡片 --- */
.article-card {
  background: #fff;
  border-radius: var(--radius-card);
  overflow: hidden;
  box-shadow: var(--shadow-card);
  transition: transform var(--transition-base), box-shadow var(--transition-base);
}

.article-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-card-hover);
}

.article-card .article-img {
  height: 180px;
  background: var(--color-bg-dark);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-gold);
  font-size: 32px;
  overflow: hidden;
}

.article-card .article-body {
  padding: 20px;
}

.article-card .article-tag {
  font-size: 12px;
  color: var(--color-primary);
  font-weight: 600;
  letter-spacing: 1px;
  margin-bottom: 8px;
}

.article-card h4 {
  font-size: 16px;
  margin-bottom: 8px;
}

.article-card .article-excerpt {
  font-size: 14px;
  color: var(--color-gray);
  line-height: 1.6;
}

.article-card .article-date {
  font-size: 12px;
  color: var(--color-gray-light);
  margin-top: 12px;
}

/* --- 表单 --- */
.form-group {
  margin-bottom: 20px;
}

.form-group label {
  display: block;
  font-size: 14px;
  font-weight: 600;
  color: var(--color-text);
  margin-bottom: 6px;
  letter-spacing: 0.5px;
}

.form-group input,
.form-group textarea,
.form-group select {
  width: 100%;
  padding: 12px 16px;
  font-size: 15px;
  font-family: var(--font-body);
  color: var(--color-text);
  background: #fff;
  border: 1.5px solid rgba(200,169,126,0.2);
  border-radius: var(--radius-btn);
  transition: border-color var(--transition-base);
  outline: none;
}

.form-group input:focus,
.form-group textarea:focus,
.form-group select:focus {
  border-color: var(--color-gold);
}

.form-group textarea {
  min-height: 120px;
  resize: vertical;
}

/* --- 统计数字 --- */
.stat-item {
  text-align: center;
}

.stat-item .stat-number {
  font-size: 36px;
  font-weight: 700;
  color: var(--color-primary);
  letter-spacing: -0.5px;
  line-height: 1;
  margin-bottom: 8px;
}

.stat-item .stat-label {
  font-size: 14px;
  color: var(--color-gray);
  letter-spacing: 1px;
}

@media (max-width: 768px) {
  .stat-item .stat-number { font-size: 28px; }
}

/* --- 优势条目 --- */
.advantage-item {
  display: flex;
  gap: 16px;
  align-items: flex-start;
}

.advantage-item .adv-icon {
  width: 44px;
  height: 44px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 6px;
  background: rgba(45,85,67,0.08);
  color: var(--color-green);
  font-size: 20px;
  flex-shrink: 0;
}

.advantage-item h4 {
  font-size: 16px;
  margin-bottom: 4px;
}

.advantage-item p {
  font-size: 14px;
  color: var(--color-gray);
}

/* --- 页面顶部间距 (补偿固定导航) --- */
.page-top {
  padding-top: 72px;
}

/* --- 内容容器 --- */
.container {
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 16px;
}

@media (min-width: 768px) {
  .container { padding: 0 32px; }
}

/* --- 区块 --- */
.section {
  padding: 40px 0;
}

@media (min-width: 768px) {
  .section { padding: 64px 0; }
}

.section-bg-white {
  background: #fff;
}

.section-bg-base {
  background: var(--color-bg);
}

.section-bg-dark {
  background: var(--color-text);
  color: rgba(255,255,255,0.85);
}

.section-bg-dark h2,
.section-bg-dark h3,
.section-bg-dark h4 {
  color: #fff;
}

.section-bg-dark p {
  color: rgba(255,255,255,0.7);
}

/* --- 预约表单页 --- */
.appointment-section {
  background: var(--color-bg);
}

/* --- 联系信息 --- */
.contact-item {
  display: flex;
  gap: 16px;
  align-items: center;
  margin-bottom: 24px;
}

.contact-item .contact-icon {
  width: 44px;
  height: 44px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 6px;
  background: rgba(140,49,48,0.08);
  color: var(--color-primary);
  font-size: 20px;
  flex-shrink: 0;
}

.contact-item h4 {
  font-size: 16px;
  margin-bottom: 2px;
}

.contact-item p {
  font-size: 14px;
  color: var(--color-gray);
  margin-bottom: 0;
}

/* --- 药膳标签 --- */
.tag {
  display: inline-block;
  padding: 4px 12px;
  border-radius: 4px;
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.5px;
}

.tag-primary {
  background: rgba(140,49,48,0.1);
  color: var(--color-primary);
}

.tag-gold {
  background: rgba(200,169,126,0.15);
  color: var(--color-gold-dark);
}

.tag-green {
  background: rgba(45,85,67,0.1);
  color: var(--color-green);
}

/* --- 面包屑 --- */
.breadcrumb {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 14px;
  color: var(--color-gray);
  margin-bottom: 32px;
}

.breadcrumb a {
  color: var(--color-gray);
  text-decoration: none;
  transition: color var(--transition-base);
}

.breadcrumb a:hover {
  color: var(--color-primary);
}

.breadcrumb .sep {
  color: var(--color-gray-light);
}

/* --- 简介页图文 --- */
.about-layout {
  display: grid;
  grid-template-columns: 1fr;
  gap: 40px;
  align-items: center;
}

@media (min-width: 768px) {
  .about-layout {
    grid-template-columns: 1fr 1fr;
    gap: 48px;
  }
}

.about-img-box {
  background: var(--color-bg-dark);
  border-radius: var(--radius-card);
  height: 300px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-gold);
  font-size: 48px;
  overflow: hidden;
}

@media (min-width: 768px) {
  .about-img-box { height: 400px; }
}

/* --- 诊疗详情 --- */
.treatment-detail {
  display: grid;
  grid-template-columns: 1fr;
  gap: 32px;
}

@media (min-width: 768px) {
  .treatment-detail {
    grid-template-columns: 1fr 1fr;
    gap: 40px;
  }
}

.treatment-img {
  background: var(--color-bg-dark);
  border-radius: var(--radius-card);
  height: 280px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-gold);
  font-size: 40px;
}

@media (min-width: 768px) {
  .treatment-img { height: 360px; }
}

/* --- 微信图标自定义 --- */
.wechat-icon {
  position: relative;
  display: inline-flex;
}

/* --- 回到顶部 --- */
.float-back-top {
  position: fixed;
  right: 16px;
  bottom: 16px;
  z-index: 900;
  width: 44px;
  height: 44px;
  border-radius: 6px;
  background: var(--color-text);
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 18px;
  cursor: pointer;
  opacity: 0;
  transform: translateY(8px);
  transition: opacity var(--transition-base), transform var(--transition-base), background-color var(--transition-base);
  text-decoration: none;
}

.float-back-top.visible {
  opacity: 1;
  transform: translateY(0);
}

.float-back-top:hover {
  background: var(--color-primary);
}

@media (max-width: 360px) {
  .float-back-top { right: 8px; bottom: 8px; width: 40px; height: 40px; }
}