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

html {
  scroll-behavior: smooth;
}

body {
  font-family: 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
  background: #000;
  color: #e0e0e0;
  line-height: 1.6;
  overflow-x: hidden;
}

.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
}

/* 导航 */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  background: rgba(0, 0, 0, 0.85);
  backdrop-filter: blur(12px);
  z-index: 999;
  border-bottom: 1px solid rgba(100, 150, 255, 0.1);
}

.navbar .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  height: 70px;
}

.logo {
  font-size: 20px;
  font-weight: 700;
  color: #4fd1ff;
  letter-spacing: 1px;
}

.menu {
  list-style: none;
  display: flex;
  gap: 28px;
}

.menu a {
  color: #c0d6ff;
  text-decoration: none;
  font-size: 15px;
  transition: color 0.3s;
}

.menu a:hover {
  color: #4fd1ff;
}

/* 动态太阳系背景 */
.hero {
  width: 100%;
  height: 100vh;
  position: relative;
  display: flex;
  align-items: center;
  overflow: hidden;
  background: radial-gradient(ellipse at center, #0a102a 0%, #000 70%);
}

.solar-system {
  position: absolute;
  width: 1200px;
  height: 1200px;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  z-index: 1;
}

.sun {
  position: absolute;
  width: 60px;
  height: 60px;
  background: #ffcc00;
  border-radius: 50%;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  box-shadow: 0 0 40px #ff9900, 0 0 80px #ff6600;
}

.orbit {
  position: absolute;
  border: 1px solid rgba(100, 150, 255, 0.15);
  border-radius: 50%;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  animation: rotate 20s linear infinite;
}

.orbit1 { width: 180px; height: 180px; animation-duration: 6s; }
.orbit2 { width: 260px; height: 260px; animation-duration: 10s; }
.orbit3 { width: 340px; height: 340px; animation-duration: 14s; }
.orbit4 { width: 440px; height: 440px; animation-duration: 18s; }
.orbit5 { width: 600px; height: 600px; animation-duration: 28s; }

.planet {
  position: absolute;
  border-radius: 50%;
  top: 0;
  left: 50%;
  transform: translateX(-50%);
}

.mercury { width: 8px; height: 8px; background: #aaa; }
.venus   { width: 14px; height: 14px; background: #ffc988; }
.earth   { width: 16px; height: 16px; background: #4f9eff; }
.mars    { width: 12px; height: 12px; background: #ff7048; }
.jupiter { width: 36px; height: 36px; background: #e9a576; }

@keyframes rotate {
  0% { transform: translate(-50%, -50%) rotate(0deg); }
  100% { transform: translate(-50%, -50%) rotate(360deg); }
}

.hero-overlay {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 5, 20, 0.6);
  z-index: 2;
}

.hero-content {
  position: relative;
  z-index: 3;
  max-width: 700px;
}

.hero h1 {
  font-size: 52px;
  line-height: 1.15;
  margin-bottom: 24px;
  color: #fff;
}

.hero p {
  font-size: 18px;
  color: #b0c4de;
  margin-bottom: 32px;
}

.hero-buttons {
  display: flex;
  gap: 16px;
}

.btn {
  padding: 14px 30px;
  border-radius: 4px;
  text-decoration: none;
  font-weight: 600;
  transition: all 0.3s;
}

.btn-primary {
  background: #4fd1ff;
  color: #000;
}

.btn-primary:hover {
  background: #33bbff;
}

.btn-outline {
  border: 1px solid #4fd1ff;
  color: #4fd1ff;
  background: transparent;
}

.btn-outline:hover {
  background: rgba(79, 209, 255, 0.1);
}

/* 区块 */
.section {
  padding: 100px 0;
}

.dark { background: #020718; }
.darker { background: #000410; }

.section-head {
  margin-bottom: 50px;
}

.section-head h2 {
  font-size: 36px;
  margin-bottom: 10px;
  color: #fff;
}

.section-head p {
  color: #889abd;
  max-width: 600px;
}

/* 卡片网格 */
.grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 30px;
}

.card {
  background: rgba(0, 20, 60, 0.3);
  border: 1px solid rgba(100, 150, 255, 0.1);
  border-radius: 8px;
  overflow: hidden;
  transition: transform 0.3s, border-color 0.3s;
}

.card:hover {
  transform: translateY(-6px);
  border-color: #4fd1ff;
}

.card-img {
  height: 200px;
  background: linear-gradient(45deg, #0a2a5a, #103a7a);
}

.card-body {
  padding: 24px;
}

.card h3 {
  font-size: 20px;
  margin-bottom: 10px;
  color: #fff;
}

.card p {
  font-size: 15px;
  color: #a0b4d0;
}

/* 页脚 */
.footer {
  padding: 50px 0 30px;
  background: #000;
  text-align: center;
  border-top: 1px solid rgba(100, 150, 255, 0.1);
}

.footer p {
  color: #778da9;
  font-size: 14px;
  margin-bottom: 8px;
}

.beian a {
  color: #4fd1ff;
  text-decoration: none;
}