/* ===== TFM 细胞牵引力显微镜介绍页样式 - 杭州表面力科技有限公司 ===== */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

:root {
  --brand-1: #1e6fff;
  --brand-2: #00c6fb;
  --brand-dark: #0a1c3d;
  --text-dark: #1f2d3d;
  --text-muted: #8492a6;
  --bg-soft: #eef3fb;
  --card-bg: #ffffff;
  --border-color: #e4e9f0;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: "Microsoft YaHei", "PingFang SC", "Helvetica Neue", Arial, sans-serif;
  background: #f7f9fd;
  color: var(--text-dark);
  -webkit-font-smoothing: antialiased;
  line-height: 1.7;
}

/* ===== 顶部导航 ===== */
.tfm-nav {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border-color);
}

.tfm-nav .nav-inner {
  max-width: 1120px;
  margin: 0 auto;
  padding: 0 24px;
  height: 64px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-brand {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
}

.nav-brand img {
  height: 32px;
}

.nav-brand .brand-text {
  font-size: 15px;
  font-weight: 600;
  color: var(--brand-dark);
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 8px;
}

.nav-links a {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 8px 16px;
  border-radius: 8px;
  font-size: 13px;
  text-decoration: none;
  color: var(--text-dark);
  transition: background 0.2s ease, color 0.2s ease;
}

.nav-links a:hover {
  background: var(--bg-soft);
  color: var(--brand-1);
}

.nav-links a.nav-btn-primary {
  background: linear-gradient(90deg, var(--brand-1), var(--brand-2));
  color: #ffffff;
  font-weight: 600;
}

.nav-links a.nav-btn-primary:hover {
  background: linear-gradient(90deg, #175ad6, #00a9e0);
  color: #ffffff;
}

/* ===== Hero 区 ===== */
.tfm-hero {
  position: relative;
  overflow: hidden;
  background: linear-gradient(135deg, #0a1c3d 0%, #123a6b 55%, #0e5f9e 100%);
  color: #ffffff;
  padding: 88px 24px 96px;
  text-align: center;
}

.tfm-hero::before {
  content: "";
  position: absolute;
  width: 640px;
  height: 640px;
  border-radius: 50%;
  border: 1px solid rgba(0, 198, 251, 0.18);
  top: -260px;
  right: -180px;
}

.tfm-hero::after {
  content: "";
  position: absolute;
  width: 420px;
  height: 420px;
  border-radius: 50%;
  border: 1px solid rgba(0, 198, 251, 0.14);
  bottom: -180px;
  left: -120px;
}

.hero-inner {
  position: relative;
  z-index: 1;
  max-width: 860px;
  margin: 0 auto;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 16px;
  border-radius: 999px;
  border: 1px solid rgba(0, 198, 251, 0.4);
  background: rgba(0, 198, 251, 0.12);
  font-size: 13px;
  letter-spacing: 1px;
  color: #7fd9ff;
}

.hero-inner h1 {
  margin-top: 22px;
  font-size: 38px;
  font-weight: 700;
  letter-spacing: 1px;
}

.hero-inner .hero-en {
  margin-top: 10px;
  font-size: 15px;
  letter-spacing: 1.5px;
  color: rgba(255, 255, 255, 0.65);
}

.hero-inner .hero-desc {
  margin: 26px auto 0;
  max-width: 680px;
  font-size: 15px;
  line-height: 1.9;
  color: rgba(255, 255, 255, 0.82);
}

.hero-points {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 12px;
  margin-top: 34px;
}

.hero-points span {
  padding: 8px 18px;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.08);
  border: 1px solid rgba(255, 255, 255, 0.14);
  font-size: 13px;
  color: rgba(255, 255, 255, 0.9);
}

/* ===== 内容区 ===== */
.tfm-section {
  max-width: 1120px;
  margin: 0 auto;
  padding: 72px 24px;
}

.section-head {
  text-align: center;
  margin-bottom: 44px;
}

.section-head .section-tag {
  display: inline-block;
  font-size: 12px;
  letter-spacing: 2px;
  color: var(--brand-1);
  text-transform: uppercase;
}

.section-head h2 {
  margin-top: 10px;
  font-size: 28px;
  font-weight: 700;
  color: var(--brand-dark);
}

.section-head .section-line {
  width: 48px;
  height: 3px;
  margin: 16px auto 0;
  border-radius: 2px;
  background: linear-gradient(90deg, var(--brand-1), var(--brand-2));
}

/* ===== 原理步骤 ===== */
.principles {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 18px;
  counter-reset: step;
}

.principle-card {
  position: relative;
  background: var(--card-bg);
  border: 1px solid var(--border-color);
  border-radius: 14px;
  padding: 24px 20px 20px;
  text-align: center;
  box-shadow: 0 4px 16px rgba(10, 28, 61, 0.05);
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.principle-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 14px 30px rgba(30, 111, 255, 0.12);
}

.principle-card::before {
  counter-increment: step;
  content: counter(step);
  position: absolute;
  top: -12px;
  left: 50%;
  transform: translateX(-50%);
  width: 26px;
  height: 26px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--brand-1), var(--brand-2));
  color: #ffffff;
  font-size: 13px;
  font-weight: 700;
  line-height: 26px;
}

.principle-icon {
  width: 44px;
  height: 44px;
  margin: 8px auto 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 10px;
  background: rgba(30, 111, 255, 0.08);
  color: var(--brand-1);
}

.principle-icon svg {
  width: 24px;
  height: 24px;
}

.principle-card h3 {
  font-size: 15px;
  font-weight: 600;
  color: var(--brand-dark);
}

.principle-card p {
  margin-top: 8px;
  font-size: 13px;
  line-height: 1.75;
  color: var(--text-muted);
  text-align: left;
}

/* ===== 特点卡片 ===== */
.features {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}

.feature-card {
  background: var(--card-bg);
  border: 1px solid var(--border-color);
  border-radius: 14px;
  padding: 26px;
  box-shadow: 0 4px 16px rgba(10, 28, 61, 0.05);
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.feature-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 14px 30px rgba(30, 111, 255, 0.12);
}

.feature-icon {
  width: 46px;
  height: 46px;
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: linear-gradient(135deg, rgba(30, 111, 255, 0.12), rgba(0, 198, 251, 0.12));
  color: var(--brand-1);
}

.feature-icon svg {
  width: 24px;
  height: 24px;
}

.feature-card h3 {
  margin-top: 16px;
  font-size: 16px;
  font-weight: 600;
  color: var(--brand-dark);
}

.feature-card p {
  margin-top: 10px;
  font-size: 13.5px;
  line-height: 1.8;
  color: var(--text-muted);
}

/* ===== 应用领域 ===== */
.applications {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}

.app-card {
  background: var(--card-bg);
  border: 1px solid var(--border-color);
  border-radius: 14px;
  padding: 24px;
  display: flex;
  gap: 16px;
  align-items: flex-start;
  box-shadow: 0 4px 16px rgba(10, 28, 61, 0.05);
}

.app-card .app-index {
  flex-shrink: 0;
  width: 36px;
  height: 36px;
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: linear-gradient(135deg, var(--brand-1), var(--brand-2));
  color: #ffffff;
  font-size: 15px;
  font-weight: 700;
}

.app-card h3 {
  font-size: 15px;
  font-weight: 600;
  color: var(--brand-dark);
}

.app-card p {
  margin-top: 6px;
  font-size: 13px;
  line-height: 1.75;
  color: var(--text-muted);
}

/* ===== 底部 CTA ===== */
.tfm-cta {
  text-align: center;
  background: linear-gradient(135deg, #0a1c3d 0%, #123a6b 55%, #0e5f9e 100%);
  color: #ffffff;
  padding: 72px 24px;
}

.tfm-cta h2 {
  font-size: 26px;
  font-weight: 700;
}

.tfm-cta p {
  margin-top: 14px;
  font-size: 14px;
  color: rgba(255, 255, 255, 0.75);
}

.tfm-cta .cta-actions {
  display: flex;
  justify-content: center;
  gap: 16px;
  margin-top: 30px;
  flex-wrap: wrap;
}

.cta-btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 12px 28px;
  border-radius: 999px;
  font-size: 14px;
  font-weight: 600;
  text-decoration: none;
  transition: transform 0.2s ease, box-shadow 0.2s ease, opacity 0.2s ease;
}

.cta-btn:hover {
  transform: translateY(-2px);
}

.cta-btn-primary {
  background: linear-gradient(90deg, var(--brand-1), var(--brand-2));
  color: #ffffff;
  box-shadow: 0 8px 24px rgba(0, 198, 251, 0.3);
}

.cta-btn-ghost {
  border: 1px solid rgba(255, 255, 255, 0.4);
  color: #ffffff;
  background: rgba(255, 255, 255, 0.08);
}

/* ===== 页脚 ===== */
.tfm-footer {
  background: #081527;
  color: rgba(255, 255, 255, 0.55);
  text-align: center;
  padding: 28px 24px;
  font-size: 13px;
}

.tfm-footer .footer-brand {
  color: rgba(255, 255, 255, 0.85);
  font-weight: 600;
}

/* ===== 响应式 ===== */
@media (max-width: 960px) {
  .principles {
    grid-template-columns: repeat(3, 1fr);
  }
  .features,
  .applications {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 640px) {
  .tfm-hero {
    padding: 64px 20px 72px;
  }
  .hero-inner h1 {
    font-size: 27px;
  }
  .principles {
    grid-template-columns: repeat(2, 1fr);
  }
  .features,
  .applications {
    grid-template-columns: 1fr;
  }
  .nav-links a.nav-text {
    display: none;
  }
  .video-block {
    padding: 18px 14px 16px;
  }
  .tutorial-intro {
    font-size: 13px;
  }
}

/* ===== 双列功能卡片（软件说明 / 优势） ===== */
.grid-2col {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
}

/* ===== 软件使用步骤（纵向步骤条） ===== */
.steps-list {
  display: flex;
  flex-direction: column;
  gap: 16px;
  max-width: 900px;
  margin: 0 auto;
}

.step-item {
  display: flex;
  align-items: flex-start;
  gap: 18px;
  background: var(--card-bg);
  border: 1px solid var(--border-color);
  border-radius: 14px;
  padding: 20px 24px;
  box-shadow: 0 4px 16px rgba(10, 28, 61, 0.05);
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.step-item:hover {
  transform: translateY(-2px);
  box-shadow: 0 12px 28px rgba(30, 111, 255, 0.1);
}

.step-number {
  flex-shrink: 0;
  width: 38px;
  height: 38px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--brand-1), var(--brand-2));
  color: #ffffff;
  font-weight: 700;
  font-size: 16px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.step-content h3 {
  font-size: 16px;
  font-weight: 600;
  color: var(--brand-dark);
}

.step-content p {
  margin-top: 6px;
  font-size: 13.5px;
  color: var(--text-muted);
}

.step-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 10px;
}

.step-tags span {
  background: #f0f4fc;
  padding: 3px 12px;
  border-radius: 999px;
  font-size: 12px;
  color: var(--brand-1);
}

/* ===== 文档下载 ===== */
.docs-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 20px;
  max-width: 720px;
  margin: 0 auto;
}

.doc-card {
  display: flex;
  flex-direction: column;
  background: var(--card-bg);
  border: 1px solid var(--border-color);
  border-radius: 14px;
  padding: 26px;
  box-shadow: 0 4px 16px rgba(10, 28, 61, 0.05);
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.doc-card:hover {
  transform: translateY(-3px);
  box-shadow: 0 14px 30px rgba(30, 111, 255, 0.12);
}

.doc-card h3 {
  font-size: 16px;
  font-weight: 600;
  color: var(--brand-dark);
  display: flex;
  align-items: center;
  gap: 8px;
}

.doc-card .doc-desc {
  margin-top: 8px;
  font-size: 13.5px;
  color: var(--text-muted);
  flex: 1;
}

.doc-card .doc-meta {
  margin-top: 8px;
  font-size: 12.5px;
  color: #6a7f9a;
}

.doc-actions {
  display: flex;
  gap: 10px;
  margin-top: 18px;
  flex-wrap: wrap;
}

.doc-btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 9px 20px;
  border-radius: 999px;
  font-size: 13px;
  font-weight: 600;
  text-decoration: none;
  transition: transform 0.2s ease, box-shadow 0.2s ease, background 0.2s ease;
}

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

.doc-btn-primary {
  background: linear-gradient(90deg, var(--brand-1), var(--brand-2));
  color: #ffffff;
  box-shadow: 0 6px 18px rgba(30, 111, 255, 0.22);
}

.doc-btn-outline {
  border: 1px solid #bbcfe0;
  color: var(--brand-1);
  background: transparent;
}

.doc-btn-outline:hover {
  background: #eaf0fa;
}

/* ===== 视频教程 ===== */
.tutorial-intro {
  text-align: center;
  margin: -24px 0 40px;
  font-size: 14px;
  color: var(--text-muted);
}

.video-block {
  position: relative;
  max-width: 900px;
  margin: 0 auto;
  background: var(--card-bg);
  border: 1px solid var(--border-color);
  border-radius: 18px;
  padding: 30px 32px 28px;
  box-shadow: 0 10px 32px rgba(10, 28, 61, 0.07);
  overflow: hidden;
  transition: transform 0.25s ease, box-shadow 0.25s ease;
}

.video-block:hover {
  transform: translateY(-3px);
  box-shadow: 0 18px 40px rgba(30, 111, 255, 0.14);
}

.video-container {
  position: relative;
  padding-bottom: 56.25%;
  height: 0;
  overflow: hidden;
  border-radius: 14px;
  background: #0b1a33;
  border: 1px solid #17345a;
  box-shadow: 0 8px 24px rgba(10, 28, 61, 0.22);
}

.video-container video {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
}

.video-caption {
  margin-top: 22px;
  padding-top: 18px;
  border-top: 1px dashed var(--border-color);
  font-size: 13.5px;
  color: var(--text-muted);
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 12px;
  flex-wrap: wrap;
}

.video-caption .tag {
  background: linear-gradient(90deg, rgba(30, 111, 255, 0.12), rgba(0, 198, 251, 0.12));
  padding: 4px 14px;
  border-radius: 999px;
  font-size: 12.5px;
  font-weight: 600;
  color: var(--brand-1);
}

/* 双列 / 文档网格响应式 */
@media (max-width: 760px) {
  .grid-2col,
  .docs-grid {
    grid-template-columns: 1fr;
  }
}

/* ===== 右侧导航栏（无底框 · 垂直居中） ===== */
.side-nav {
  position: fixed;
  right: 28px;
  top: 50%;
  transform: translateY(-50%);
  z-index: 90;
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding: 8px 6px;
}

.side-nav a {
  position: relative;
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 6px 10px;
  border-radius: 8px;
  font-size: 13px;
  font-weight: 500;
  text-decoration: none;
  color: #7d8aa0;
  white-space: nowrap;
  transition: color 0.2s ease, background 0.2s ease;
}

.side-nav a .side-nav-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: #c9d4e4;
  flex-shrink: 0;
  transition: background 0.2s ease, box-shadow 0.2s ease, transform 0.2s ease;
}

.side-nav a:hover {
  color: var(--brand-1);
  background: rgba(30, 111, 255, 0.06);
}

.side-nav a:hover .side-nav-dot {
  background: var(--brand-1);
}

.side-nav a.active {
  color: var(--brand-1);
  font-weight: 700;
}

.side-nav a.active::before {
  content: "";
  position: absolute;
  left: -6px;
  top: 50%;
  transform: translateY(-50%);
  width: 3px;
  height: 16px;
  border-radius: 999px;
  background: linear-gradient(180deg, var(--brand-1), var(--brand-2));
}

.side-nav a.active .side-nav-dot {
  background: linear-gradient(90deg, var(--brand-1), var(--brand-2));
  box-shadow: 0 0 0 4px rgba(30, 111, 255, 0.14);
  transform: scale(1.2);
}

/* 窄屏隐藏右侧导航栏 */
@media (max-width: 1080px) {
  .side-nav {
    display: none;
  }
}