/* === CSS 变量 === */
:root {
  --color-primary: #1A237E;
  --color-primary-light: #283593;
  --color-accent: #FF8F00;
  --color-accent-light: #FFB300;
  --color-bg: #F5F7FA;
  --color-white: #FFFFFF;
  --color-text: #333333;
  --color-text-light: #666666;
  --color-border: #E0E0E0;
  --font-zh: "Microsoft YaHei", "PingFang SC", "Hiragino Sans GB", sans-serif;
  --font-en: "Segoe UI", system-ui, -apple-system, sans-serif;
  --max-width: 1200px;
  --nav-height: 80px;
}

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

html { scroll-behavior: smooth; }

body {
  font-family: var(--font-zh);
  color: var(--color-text);
  background: var(--color-bg);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--color-primary); text-decoration: none; }
a:hover { color: var(--color-accent); }

img { max-width: 100%; height: auto; display: block; }

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 20px;
}

/* === 排版 === */
h1, h2, h3, h4 { color: var(--color-primary); line-height: 1.3; }
h1 { font-size: 2rem; }
h2 { font-size: 1.6rem; margin-bottom: 16px; }
h3 { font-size: 1.2rem; margin-bottom: 8px; }
p { margin-bottom: 12px; color: var(--color-text-light); }

.section {
  padding: 60px 0;
}

.section-title {
  text-align: center;
  margin-bottom: 40px;
}
.section-title h2 { margin-bottom: 8px; }
.section-title p { font-size: 1.05rem; }

/* === 导航栏 === */
.navbar {
  background: var(--color-white);
  border-bottom: 1px solid var(--color-border);
  position: sticky;
  top: 0;
  z-index: 100;
  height: var(--nav-height);
}

.navbar .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: 10px;
}

.nav-logo img { height: 60px; }

.nav-logo span {
  font-size: 1.3rem;
  font-weight: bold;
  color: var(--color-primary);
}

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

.nav-links a {
  color: var(--color-text);
  font-size: 0.95rem;
  padding: 8px 0;
  border-bottom: 2px solid transparent;
  transition: border-color 0.2s;
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--color-primary);
  border-bottom-color: var(--color-accent);
}

/* 移动端汉堡菜单 */
.nav-toggle {
  display: none;
  background: none;
  border: none;
  font-size: 1.5rem;
  cursor: pointer;
  color: var(--color-primary);
}

@media (max-width: 768px) {
  .nav-links {
    display: none;
    position: absolute;
    top: var(--nav-height);
    left: 0;
    right: 0;
    background: var(--color-white);
    flex-direction: column;
    gap: 0;
    box-shadow: 0 4px 12px rgba(0,0,0,0.1);
  }
  .nav-links.open { display: flex; }
  .nav-links a {
    padding: 14px 20px;
    border-bottom: 1px solid var(--color-border);
  }
  .nav-toggle { display: block; }
}

/* === 页脚 === */
.footer {
  background: var(--color-primary);
  color: rgba(255,255,255,0.8);
  padding: 30px 0;
  text-align: center;
  font-size: 0.85rem;
}

.footer a {
  color: rgba(255,255,255,0.9);
  text-decoration: underline;
}

.footer .beian { margin-top: 8px; }

/* === 按钮 === */
.btn {
  display: inline-block;
  padding: 12px 28px;
  border-radius: 4px;
  font-size: 1rem;
  font-weight: bold;
  border: none;
  cursor: pointer;
  transition: all 0.2s;
}

.btn-primary {
  background: var(--color-accent);
  color: var(--color-white);
}
.btn-primary:hover { background: #E67E00; }

.btn-outline {
  background: transparent;
  color: var(--color-white);
  border: 2px solid var(--color-white);
}
.btn-outline:hover { background: rgba(255,255,255,0.1); }

/* === 卡片 === */
.cards {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.card {
  background: var(--color-white);
  border-radius: 8px;
  padding: 32px 24px;
  text-align: center;
  box-shadow: 0 2px 12px rgba(0,0,0,0.06);
  transition: transform 0.2s, box-shadow 0.2s;
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: 0 8px 24px rgba(0,0,0,0.1);
}

.card-icon {
  font-size: 2.5rem;
  margin-bottom: 16px;
}

.card h3 { margin-bottom: 12px; }

@media (max-width: 768px) {
  .cards { grid-template-columns: 1fr; }
}

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

.form-group label {
  display: block;
  margin-bottom: 6px;
  font-weight: bold;
  color: var(--color-text);
}

.form-group input,
.form-group textarea {
  width: 100%;
  padding: 10px 14px;
  border: 1px solid var(--color-border);
  border-radius: 4px;
  font-size: 0.95rem;
  font-family: var(--font-zh);
  transition: border-color 0.2s;
}

.form-group input:focus,
.form-group textarea:focus {
  outline: none;
  border-color: var(--color-primary);
}

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

.form-error { color: #D32F2F; font-size: 0.85rem; margin-top: 4px; display: none; }

/* === Hero 区 === */
.hero {
  background: url('../images/hero-bg.jpg') center/cover no-repeat;
  color: var(--color-white);
  text-align: center;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  padding: 100px 20px;
}

.hero h1 {
  color: var(--color-white);
  font-size: 2.6rem;
  margin-bottom: 16px;
  text-shadow: 0 2px 12px rgba(0,0,0,0.6);
}

.hero p {
  color: #ffffff;
  font-size: 1.15rem;
  max-width: 600px;
  margin: 0 auto 32px;
  text-shadow: 0 1px 8px rgba(0,0,0,0.5);
}

/* === 联系页双栏 === */
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 32px;
  max-width: 900px;
  margin: 0 auto;
}

@media (max-width: 768px) {
  .contact-grid { grid-template-columns: 1fr; }
}

/* === 工具类 === */
.text-center { text-align: center; }
.mt-20 { margin-top: 20px; }
.mt-40 { margin-top: 40px; }