/* ========== 全局重置 ========== */
* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }

body {
  min-height: 100vh;
  font-family: 'Arial', 'PingFang SC', 'Microsoft YaHei', sans-serif;
  color: #1a2a4a;
  letter-spacing: 0.5px;
  background-color: #fafbfc;
  background-image:
    radial-gradient(ellipse at 15% 10%, rgba(59,145,236,0.08) 0%, transparent 50%),
    radial-gradient(ellipse at 85% 90%, rgba(236,198,59,0.10) 0%, transparent 50%),
    radial-gradient(ellipse at 50% 50%, rgba(59,145,236,0.04) 0%, transparent 60%);
  background-attachment: fixed;
  overflow-x: hidden;
}

/* 背景气泡画布 —— 金蓝气泡云 */
#stars {
  position: fixed;
  top: 0; left: 0;
  width: 100%; height: 100%;
  z-index: 0;
  pointer-events: none;
}

/* 固定任务栏 */
.navbar {
  position: fixed;
  top: 0; left: 0; right: 0;
  height: 64px;
  background: rgba(255,255,255,0.92);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border-bottom: 3px solid transparent;
  border-image: linear-gradient(90deg, #ecc63b, #3b91ec) 1;
  display: flex;
  align-items: center;
  padding: 0 32px;
  z-index: 100;
  /* 默认隐藏，等 .show 后滑下来 */
  opacity: 0;
  transform: translateY(-100%);
  transition: opacity 0.7s ease,
              transform 0.8s cubic-bezier(0.16, 1, 0.3, 1);
}
.navbar.show {
  opacity: 1;
  transform: translateY(0);
}

.nav-logo {
  display: flex;
  align-items: center;
  text-decoration: none;
  z-index: 2;
}

.nav-logo-img {
  height: 48px;
  width: auto;
  display: block;
  object-fit: contain;
}

.nav-menu {
  position: absolute;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  gap: 42px;
  list-style: none;
}

.nav-link {
  position: relative;
  color: #4a5568;
  text-decoration: none;
  font-size: 15px;
  letter-spacing: 1px;
  padding: 6px 2px;
  transition: color 0.3s ease;
}
.nav-link::after {
  content: '';
  position: absolute;
  left: 0; bottom: 0;
  width: 0; height: 2px;
  background: linear-gradient(90deg, #ecc63b, #3b91ec);
  transition: width 0.3s ease;
}
.nav-link:hover,
.nav-link.active { color: #3b91ec; }
.nav-link:hover::after,
.nav-link.active::after { width: 100%; }

/* 主体内容（默认隐藏，等 .show 后渐入上浮） */
#content {
  position: relative;
  z-index: 1;
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 1.1s ease 0.15s,
              transform 1.1s cubic-bezier(0.16, 1, 0.3, 1) 0.15s;
  padding-top: 80px;
}
#content.show {
  opacity: 1;
  transform: translateY(0);
}

/* Hero 首屏（仅主页用） */
.hero {
  min-height: calc(100vh - 80px);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 40px 24px 60px;
  text-align: center;
}

/* 大字容器 */
.hero-title {
  font-family: 'Microsoft YaHei', 'PingFang SC', 'Source Han Sans SC',
               'Noto Sans CJK SC', 'Heiti SC', 'SimHei', sans-serif;
  font-size: clamp(3rem, 10vw, 7rem);
  line-height: 1.15;
  letter-spacing: 0.05em;
  margin: 0;
  padding: 0;
}

/* 品牌主字：深蓝实心 + 柔和投影，素一点 */
.hero-brand {
  font-family: 'Microsoft YaHei', 'PingFang SC', 'Source Han Sans SC',
               'Noto Sans CJK SC', 'Heiti SC', 'SimHei', sans-serif;
  font-weight: 800;
  letter-spacing: 0.12em;
  /* ★ 纯深蓝，不做渐变 */
  color: #1a2a4a;
  /* 两层柔和投影：底下深色阴影 + 远处淡蓝光晕 */
  text-shadow:
    0 2px 0 rgba(26,42,74,0.15),
    0 8px 24px rgba(59,145,236,0.15);
}

.hero-desc {
  margin-top: 28px;
  font-size: 15px;
  letter-spacing: 6px;
  color: #6b7a99;
}

/* 卡片区（主页） */
.cards-section { padding-bottom: 110px; }

.cards {
  display: flex;
  flex-wrap: wrap;
  gap: 28px;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 32px;
}

.card-col {
  flex: 1 1 280px;
  display: flex;
}

.card {
  width: 100%;
  background: #ffffff;
  border: 1px solid rgba(59,145,236,0.12);
  border-radius: 14px;
  padding: 36px 30px 30px;
  display: flex;
  flex-direction: column;
  transition: transform 0.45s cubic-bezier(0.16, 1, 0.3, 1),
              border-color 0.45s ease,
              box-shadow 0.45s ease;
}
.card:hover {
  transform: translateY(-8px);
  border-color: rgba(59,145,236,0.55);
  box-shadow: 0 24px 60px rgba(59,145,236,0.18);
}

.card-num {
  font-size: 13px;
  letter-spacing: 3px;
  color: #3b91ec;
  margin-bottom: 18px;
}

.card-title {
  font-size: 22px;
  font-weight: 700;
  letter-spacing: 2px;
  margin-bottom: 14px;
  color: #1a2a4a;
}

.card-desc {
  flex: 1;
  font-size: 14px;
  line-height: 1.9;
  color: #6b7a99;
  margin-bottom: 26px;
}

.card-more {
  align-self: flex-start;
  color: #3b91ec;
  text-decoration: none;
  font-size: 14px;
  letter-spacing: 1px;
  transition: color 0.3s ease, letter-spacing 0.3s ease;
}
.card-more:hover {
  color: #ecc63b;
  letter-spacing: 3px;
}

/* 通用内容区块（其他页面用） */
.section {
  max-width: 1000px;
  margin: 0 auto;
  padding: 80px 32px;
}
.section-title {
  font-size: 52px;
  letter-spacing: 4px;
  margin-bottom: 40px;
  text-align: center;
}
.section-desc {
  font-size: 15px;
  line-height: 2;
  color: #6b7a99;
  text-align: center;
  margin-bottom: 30px;
}

/* 页脚 */
.footer {
  border-top: 1px solid rgba(59,145,236,0.12);
  padding: 36px 24px;
  text-align: center;
  font-size: 13px;
  letter-spacing: 0.5px;
  color: #8899b0;
}

/* 滚动渐显上浮 */
.reveal {
  opacity: 0;
  transform: translateY(40px);
  transition: opacity 0.9s ease,
              transform 0.9s cubic-bezier(0.16, 1, 0.3, 1);
}
.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

/* 移动端适配 */
@media (max-width: 720px) {
  .navbar { height: 56px; padding: 0 16px; }
  .nav-menu { gap: 16px; }
  .nav-link { font-size: 12.5px; letter-spacing: 0; }
  .nav-logo-img { height: 28px; }
  .hero-title { font-size: clamp(2.4rem, 12vw, 4rem); }
  .hero-brand { letter-spacing: 0.08em; -webkit-text-stroke: 1px #1a3a6e; }

  .cards { padding: 0 20px; gap: 20px; }
  .section { padding: 60px 20px; }
}

/* ========== 滚动提示箭头（v 字形，半透明） ========== */
.scroll-hint {
  position: fixed;
  bottom: 48px;
  left: 50%;
  transform: translateX(-50%);
  z-index: 50;
  pointer-events: none;
  opacity: 0;
  transition: opacity 0.4s ease;
}
.scroll-hint.show {
  opacity: 1;
}
.scroll-hint span {
  display: block;
  width: 18px;
  height: 18px;
  border-right: 2px solid rgba(59,145,236,0.7);
  border-bottom: 2px solid rgba(59,145,236,0.7);
  transform: rotate(45deg);
  margin: -8px auto 0;
  animation: scrollArrow 2s ease-in-out infinite;
}
.scroll-hint span:nth-child(2) {
  animation-delay: 0.25s;
}
@keyframes scrollArrow {
  0%, 100% { opacity: 0.25; transform: rotate(45deg) translate(0, 0); }
  50%      { opacity: 1;    transform: rotate(45deg) translate(3px, 3px); }
}

/* 移动端稍微上移一点，避免贴边 */
@media (max-width: 720px) {
  .scroll-hint { bottom: 16px; }
  .scroll-hint span { width: 14px; height: 14px; }
}