* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}
:root {
  --primary-dark: #1f443c;
  --primary-light: #7cc8b8;
  --bg-base: #f8faf9;
  --text-main: #1d2b27;
  --text-light: #475c56;
  --card-bg: rgba(255,255,255,0.76);
  --border-subtle: rgba(124,200,184,0.28);
  --line-gradient: linear-gradient(90deg, transparent, #7cc8b8, transparent);
}
html {
  scroll-behavior: smooth;
}
body {
  background-color: var(--bg-base);
  color: var(--text-main);
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  line-height: 1.75;
  overflow-x: hidden;
}

/* ========== 导航 ========== */
nav {
  position: fixed;
  width: 100%;
  top:0;
  z-index: 100;
  padding: 1.4rem 4rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  transition: background 0.45s ease, box-shadow 0.45s ease;
}
nav.scrolled {
  background-color: rgba(31,68,60,0.92);
  backdrop-filter: blur(10px);
  box-shadow: 0 3px 16px rgba(31,68,60,0.16);
}
.logo {
  font-size: 1.55rem;
  font-weight: 700;
  color: #fff;
  letter-spacing: 0.7px;
}
.nav-group a {
  color: rgba(255,255,255,0.82);
  text-decoration: none;
  margin-left: 2.2rem;
  font-size: 0.98rem;
  transition: color 0.3s ease;
  position: relative;
}
.nav-group a::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: -4px;
  width:0;
  height:2px;
  background-color: var(--primary-light);
  transition: width 0.3s ease;
}
.nav-group a:hover {
  color: var(--primary-light);
}
.nav-group a:hover::after {
  width:100%;
}

/* ========== Hero 首屏｜强科技感 ========== */
.hero-block {
  position: relative;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  justify-content: center;
  padding: 0 6rem;
  background: linear-gradient(140deg, #245045, #1f443c);
  overflow: hidden;
}
#particleCanvas {
  position: absolute;
  inset:0;
  opacity:0.24;
}
/* 几何装饰线条 */
.geo-line-1{
  position:absolute;
  top:15%;
  right:10%;
  width:280px;
  height:1px;
  background:var(--line-gradient);
}
.geo-line-2{
  position:absolute;
  bottom:22%;
  right:18%;
  width:180px;
  height:1px;
  background:var(--line-gradient);
}
.geo-line-3{
  position:absolute;
  top:40%;
  right:24%;
  width:1px;
  height:220px;
  background:linear-gradient(180deg, transparent, #7cc8b8, transparent);
}
.hero-content {
  position: relative;
  z-index:2;
  max-width:840px;
}
.hero-block h1 {
  font-size: 3.6rem;
  color:#fff;
  margin-bottom:1.6rem;
  letter-spacing: 1.2px;
  opacity:0;
  transform: translateY(24px);
  animation: heroTitleFade 1.2s ease-out forwards;
}
@keyframes heroTitleFade {
  to {opacity:1; transform: translateY(0);}
}
.hero-block p {
  color:rgba(255,255,255,0.86);
  font-size:1.26rem;
  margin-bottom: 2.6rem;
  opacity:0;
  transform: translateY(24px);
  animation: heroParaFade 1.2s ease-out 0.3s forwards;
}
@keyframes heroParaFade {
  to {opacity:1; transform: translateY(0);}
}
.btn-primary {
  display:inline-block;
  padding:1.15rem 2.6rem;
  background: var(--primary-light);
  color: var(--primary-dark);
  font-weight:700;
  border-radius:999px;
  text-decoration:none;
  transition: transform 0.35s ease, box-shadow 0.35s ease;
  opacity:0;
  transform: translateY(24px);
  animation: heroBtnFade 1.2s ease-out 0.6s forwards;
}
@keyframes heroBtnFade {
  to {opacity:1; transform: translateY(0);}
}
.btn-primary:hover {
  transform: translateY(-4px);
  box-shadow: 0 10px 26px rgba(124,200,184,0.38);
}
/* 底部横向扫光 */
.light-sweep {
  position:absolute;
  bottom: 90px;
  left: 50%;
  transform: translateX(-50%);
  width:420px;
  height:1px;
  background: var(--line-gradient);
  animation: sweep 5s infinite linear;
}
@keyframes sweep {
  0% {transform: translateX(-260px); opacity:0.25;}
  50% {opacity:1;}
  100% {transform: translateX(260px); opacity:0.25;}
}

/* ========== 通用区块 ========== */
.container {
  max-width:1320px;
  margin:0 auto;
  padding:7rem 2rem;
}
.section-wrap {
  position:relative;
}
.section-heading {
  font-size:2.3rem;
  color:var(--primary-dark);
  margin-bottom:1.4rem;
  position:relative;
}
.section-heading::after {
  content:"";
  display:block;
  width:80px;
  height:3px;
  background:var(--primary-light);
  margin-top:0.7rem;
}
.fade-in {
  opacity:0;
  transform: translateY(30px);
  transition: opacity 0.8s ease-out, transform 0.8s ease-out;
}
.fade-in.active {
  opacity:1;
  transform: translateY(0);
}

/* ========== 科技卡片网格｜升级悬浮光效 ========== */
.card-grid {
  display:grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap:2.4rem;
  margin-top:3.4rem;
}
.card-item {
  background: var(--card-bg);
  border:1px solid var(--border-subtle);
  border-radius:18px;
  padding:2.6rem;
  backdrop-filter: blur(10px);
  position:relative;
  overflow:hidden;
  transition: transform 0.38s ease, box-shadow 0.38s ease, border-color 0.38s ease;
}
.card-item::before {
  content:"";
  position:absolute;
  top:0;
  left:-100%;
  width:100%;
  height:100%;
  background: linear-gradient(90deg, transparent, rgba(124,200,184,0.12), transparent);
  transition: left 0.6s ease;
}
.card-item:hover::before {
  left:100%;
}
.card-item:hover {
  transform: translateY(-8px);
  box-shadow: 0 16px 36px rgba(31,68,60,0.12);
  border-color:rgba(124,200,184,0.6);
}
.card-item h3 {
  color:var(--primary-dark);
  font-size:1.4rem;
  margin-bottom: 0.9rem;
}
.card-item p {
  color:var(--text-light);
}

/* ========== 页脚 ========== */
footer {
  background-color: var(--primary-dark);
  color:rgba(255,255,255,0.78);
  text-align:center;
  padding:3rem;
  margin-top:4rem;
}

/* ========== 响应式 ========== */
@media(max-width:960px){
  nav {padding:1.1rem 1.6rem;}
  .nav-group a {margin-left:1rem;}
  .hero-block {padding:0 2rem; align-items:center; text-align:center;}
  .hero-block h1 {font-size: 2.4rem;}
  .geo-line-1,.geo-line-2,.geo-line-3 {display:none;}
}