/* 亿企赢工具平台 · 统一设计系统 */
/* 三页共用：产品展示 / 异议手册 / 平台首页 */

:root {
  /* 背景 */
  --bg: #FFFFFF;
  --bg2: #F5F5F7;
  --bg3: #FBFBFD;
  --card: #FFFFFF;

  /* 线条 */
  --line: #E5E5EA;
  --line2: #EDEDF0;

  /* 文字 */
  --txt: #1D1D1F;
  --txt2: #6E6E73;
  --txt3: #86868B;

  /* 品牌色 */
  --c1: #0071E3;
  --c2: #06A6BD;
  --amber: #C8780A;
  --green: #2E8B57;
  --orange: #D2691E;

  /* 辅助 */
  --rose: #E84A6E;

  /* 形状 */
  --radius: 22px;
  --radius-sm: 14px;

  /* 间距 */
  --maxw: 1180px;
  --section-py: 100px;
  --section-py-sm: 64px;

  /* 阴影 */
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, .06);
  --shadow: 0 4px 20px rgba(0, 0, 0, .08);
  --shadow-lg: 0 8px 40px rgba(0, 0, 0, .10);

  /* 字体 */
  --font: -apple-system, BlinkMacSystemFont, "SF Pro Display", "PingFang SC", "Microsoft YaHei", sans-serif;
}

/* ===== 全局重置 ===== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; -webkit-font-smoothing: antialiased; }
body { font-family: var(--font); color: var(--txt); background: var(--bg); line-height: 1.6; }

/* ===== 统一顶部导航 ===== */
.platform-nav {
  position: fixed; top: 0; left: 0; right: 0; z-index: 100;
  padding: 0 32px; height: 56px;
  display: flex; align-items: center; justify-content: space-between;
  background: rgba(255, 255, 255, .95);
  backdrop-filter: blur(18px) saturate(160%);
  -webkit-backdrop-filter: blur(18px) saturate(160%);
  border-bottom: 1px solid var(--line2);
  transition: border-color .3s, background .3s;
}
.platform-nav.scrolled {
  border-bottom-color: var(--line);
}
.platform-nav .nav-brand {
  font-size: 17px; font-weight: 700; letter-spacing: -.01em;
  color: var(--txt); text-decoration: none;
  display: flex; align-items: center; gap: 8px;
}
.platform-nav .nav-brand span { color: var(--txt3); font-weight: 400; font-size: 13px; }
.platform-nav .nav-links { display: flex; gap: 4px; list-style: none; }
.platform-nav .nav-links a {
  padding: 8px 18px; border-radius: 980px;
  font-size: 14px; color: var(--txt2); text-decoration: none;
  transition: background .2s, color .2s;
  letter-spacing: .01em;
}
.platform-nav .nav-links a:hover { color: var(--txt); background: var(--bg2); }
.platform-nav .nav-links a.active {
  background: var(--txt); color: #fff; font-weight: 500;
}

/* 汉堡菜单（移动端） */
.nav-toggle { display: none; width: 36px; height: 36px; border: none; background: none; cursor: pointer; padding: 6px; }
.nav-toggle span { display: block; width: 100%; height: 2px; background: var(--txt); border-radius: 2px; transition: .25s; }
.nav-toggle span + span { margin-top: 6px; }

/* ===== Section 通用 ===== */
.sec { padding: var(--section-py) 24px; }
.sec.alt { background: var(--bg2); }
.wrap { max-width: var(--maxw); margin: 0 auto; }

.sec-head { text-align: center; margin-bottom: 56px; }
.sec-head .row { display: flex; align-items: center; justify-content: center; gap: 10px; margin-bottom: 14px; }
.sec-no { font-size: 13px; color: var(--txt3); letter-spacing: .08em; font-weight: 600; }
.sec-en { font-size: 13px; color: var(--txt3); letter-spacing: .04em; text-transform: uppercase; }
.sec-line { width: 48px; height: 3px; background: var(--c1); border-radius: 2px; margin: 0 auto 20px; }
.sec-title { font-size: 44px; font-weight: 700; line-height: 1.15; letter-spacing: -.02em; margin-bottom: 14px; }
.sec-sub { font-size: 18px; color: var(--txt2); max-width: 680px; margin: 0 auto; line-height: 1.65; }

/* ===== CTA Button ===== */
.btn { display: inline-flex; align-items: center; gap: 8px; padding: 14px 32px; border-radius: 980px; font-size: 16px; font-weight: 600; text-decoration: none; cursor: pointer; border: none; transition: .25s; letter-spacing: .01em; }
.btn-primary { background: var(--c1); color: #fff; }
.btn-primary:hover { background: #005BBF; transform: translateY(-1px); box-shadow: 0 6px 24px rgba(0, 113, 227, .35); }
.btn-outline { background: transparent; color: var(--c1); border: 1.5px solid var(--c1); }
.btn-outline:hover { background: rgba(0, 113, 227, .06); }

/* ===== Reveal 入场动画 ===== */
.reveal { opacity: 0; transform: translateY(28px); transition: opacity .7s cubic-bezier(.22,1,.36,1), transform .7s cubic-bezier(.22,1,.36,1); }
.reveal.on { opacity: 1; transform: translateY(0); }

/* ===== Footer ===== */
footer { text-align: center; padding: 40px 24px; color: var(--txt3); font-size: 13px; }

/* ===== 响应式 ===== */
@media (max-width: 820px) {
  .platform-nav .nav-links { display: none; }
  .nav-toggle { display: block; }
  .platform-nav.nav-open .nav-links {
    display: flex; flex-direction: column; position: absolute; top: 56px; left: 0; right: 0;
    background: rgba(255,255,255,.96); backdrop-filter: blur(20px); padding: 12px 24px 24px;
    border-bottom: 1px solid var(--line2); gap: 2px;
  }
  .platform-nav.nav-open .nav-links a { padding: 12px 16px; border-radius: 12px; }

  .sec { padding: var(--section-py-sm) 20px; }
  .sec-title { font-size: 30px; }
  .sec-sub { font-size: 16px; }
}