/* =============================================
   上海京涛营销策划 - 公共样式表
   ============================================= */

/* ---- CSS Reset & Base ---- */
*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }

:root {
  --red: #C8000A;
  --red-dark: #9E0007;
  --red-light: #F5E6E7;
  --white: #FFFFFF;
  --black: #1A1A1A;
  --gray-100: #F7F7F7;
  --gray-200: #EEEEEE;
  --gray-400: #AAAAAA;
  --gray-600: #666666;
  --gray-800: #333333;
  --font-zh: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
  --font-en: "Arial", sans-serif;
  --max-w: 1200px;
  --transition: 0.3s ease;
}

html { scroll-behavior: smooth; font-size: 16px; }

body {
  font-family: var(--font-zh);
  color: var(--black);
  background: var(--white);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

a { text-decoration: none; color: inherit; }
ul { list-style: none; }
img { max-width: 100%; display: block; }
button { cursor: pointer; border: none; outline: none; font-family: var(--font-zh); }

/* ---- 导航栏 ---- */
.navbar {
  position: fixed; top: 0; left: 0; right: 0; z-index: 1000;
  background: var(--white);
  border-bottom: 1px solid var(--gray-200);
  transition: box-shadow var(--transition);
}
.navbar.scrolled { box-shadow: 0 2px 20px rgba(0,0,0,0.08); }

.nav-inner {
  max-width: var(--max-w); margin: 0 auto;
  display: flex; align-items: center; justify-content: space-between;
  padding: 0 40px; height: 72px;
}

.logo {
  display: flex; align-items: center; gap: 12px;
  font-size: 20px; font-weight: 700; letter-spacing: 0.05em;
}
.logo-mark {
  width: 40px; height: 40px;
  background: var(--red); color: var(--white);
  display: flex; align-items: center; justify-content: center;
  font-size: 18px; font-weight: 900;
  flex-shrink: 0;
}

.nav-links { display: flex; gap: 0; align-items: center; }
.nav-links a {
  display: block; padding: 24px 22px;
  font-size: 15px; color: var(--gray-800);
  position: relative; transition: color var(--transition);
}
.nav-links a::after {
  content: ''; position: absolute; bottom: 0; left: 50%; transform: translateX(-50%);
  width: 0; height: 3px; background: var(--red);
  transition: width var(--transition);
}
.nav-links a:hover, .nav-links a.active { color: var(--red); }
.nav-links a:hover::after, .nav-links a.active::after { width: calc(100% - 44px); }

.nav-cta {
  background: var(--red); color: var(--white) !important;
  padding: 10px 22px !important; font-size: 14px !important; font-weight: 600;
  border-radius: 2px; margin-left: 10px;
  transition: background var(--transition);
}
.nav-cta::after { display: none !important; }
.nav-cta:hover { background: var(--red-dark); }

/* 汉堡菜单 */
.hamburger { display: none; flex-direction: column; gap: 5px; cursor: pointer; padding: 5px; }
.hamburger span { width: 24px; height: 2px; background: var(--black); transition: var(--transition); }
.hamburger.open span:nth-child(1) { transform: rotate(45deg) translate(5px, 5px); }
.hamburger.open span:nth-child(2) { opacity: 0; }
.hamburger.open span:nth-child(3) { transform: rotate(-45deg) translate(5px, -5px); }

/* ---- 页面公共头部 ---- */
.page-hero {
  padding: 140px 40px 80px;
  background: var(--red);
  color: var(--white);
  text-align: center;
}
.page-hero h1 { font-size: 48px; font-weight: 900; letter-spacing: 0.1em; margin-bottom: 16px; }
.page-hero p { font-size: 18px; opacity: 0.85; max-width: 600px; margin: 0 auto; }

/* ---- 通用容器 ---- */
.container { max-width: var(--max-w); margin: 0 auto; padding: 0 40px; }

/* ---- Section 通用 ---- */
.section { padding: 100px 0; }
.section-gray { background: var(--gray-100); }
.section-label {
  font-size: 13px; font-weight: 700; letter-spacing: 0.2em; text-transform: uppercase;
  color: var(--red); margin-bottom: 12px;
  display: flex; align-items: center; gap: 10px;
}
.section-label::before { content: ''; width: 30px; height: 2px; background: var(--red); }
.section-title {
  font-size: 38px; font-weight: 900; line-height: 1.2;
  color: var(--black); margin-bottom: 20px; letter-spacing: 0.02em;
}
.section-desc { font-size: 17px; color: var(--gray-600); max-width: 600px; line-height: 1.8; }

/* ---- 按钮 ---- */
.btn {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 14px 36px; font-size: 15px; font-weight: 700;
  border-radius: 2px; transition: all var(--transition); letter-spacing: 0.05em;
}
.btn-red { background: var(--red); color: var(--white); }
.btn-red:hover { background: var(--red-dark); transform: translateY(-1px); box-shadow: 0 8px 24px rgba(200,0,10,0.3); }
.btn-outline { background: transparent; color: var(--red); border: 2px solid var(--red); }
.btn-outline:hover { background: var(--red); color: var(--white); }
.btn-white { background: var(--white); color: var(--red); }
.btn-white:hover { background: var(--gray-100); }

/* ---- Footer ---- */
.footer {
  background: var(--black); color: var(--white); padding: 60px 0 30px;
}
.footer-grid {
  display: grid; grid-template-columns: 2fr 1fr 1fr 1fr; gap: 60px;
  margin-bottom: 50px;
}
.footer-brand .logo { color: var(--white); margin-bottom: 16px; }
.footer-brand .logo-mark { background: var(--red); }
.footer-brand p { color: var(--gray-400); font-size: 14px; line-height: 1.8; }
.footer h4 { font-size: 14px; font-weight: 700; letter-spacing: 0.1em; margin-bottom: 20px; color: var(--white); }
.footer ul li { margin-bottom: 10px; }
.footer ul li a { color: var(--gray-400); font-size: 14px; transition: color var(--transition); }
.footer ul li a:hover { color: var(--red); }
.footer-bottom {
  border-top: 1px solid #333; padding-top: 24px;
  display: flex; justify-content: space-between; align-items: center;
  color: var(--gray-400); font-size: 13px;
}

/* ---- 滚动动画 ---- */
.reveal { opacity: 0; transform: translateY(30px); transition: opacity 0.7s ease, transform 0.7s ease; }
.reveal.visible { opacity: 1; transform: translateY(0); }

/* ---- 响应式 ---- */
@media (max-width: 768px) {
  .nav-links { display: none; position: fixed; top: 72px; left: 0; right: 0; background: var(--white); flex-direction: column; padding: 20px; border-top: 1px solid var(--gray-200); box-shadow: 0 10px 30px rgba(0,0,0,0.1); }
  .nav-links.open { display: flex; }
  .nav-links a { padding: 14px 0; width: 100%; border-bottom: 1px solid var(--gray-200); }
  .hamburger { display: flex; }
  .page-hero { padding: 120px 20px 60px; }
  .page-hero h1 { font-size: 32px; }
  .section { padding: 60px 0; }
  .section-title { font-size: 28px; }
  .container { padding: 0 20px; }
  .footer-grid { grid-template-columns: 1fr 1fr; gap: 30px; }
  .footer-bottom { flex-direction: column; gap: 10px; text-align: center; }
}