:root {
  /* === 品牌色 === */
  --primary: #0071e3;
  --primary-dark: #005bb5;
  --primary-light: #3b82f6;
  --secondary: #2A5298;

  /* === 功能色 === */
  --success: #10b981;
  --success-light: #d1fae5;
  --success-soft: #ecfdf5;
  --error: #dc2626;
  --error-light: #fecaca;
  --error-soft: #fef2f2;
  --warning: #f59e0b;
  --warning-light: #fde68a;
  --warning-soft: #fff7ed;

  /* === 渐变 === */
  --gradient-primary: linear-gradient(100deg, var(--primary-dark), var(--primary));
  --gradient-hover: linear-gradient(100deg, #004a9c, #0066cc);
  --gradient-accent: linear-gradient(135deg, var(--primary-light), var(--success));

  /* === 文字 === */
  --text-main: #1e293b;
  --text-secondary: #64748b;
  --text-muted: #94a3b8;

  /* === 背景 === */
  --bg-body: #f8fafc;
  --bg-card: #ffffff;
  --bg-subtle: #f1f5f9;
  --bg-hover: #f8faff;

  /* === 边框 === */
  --border: #e2e8f0;
  --border-light: #f1f5f9;

  /* === 阴影（中性，便于主题切换） === */
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.04);
  --shadow-btn: 0 2px 6px rgba(0,0,0,0.12);
  --shadow-btn-hover: 0 6px 14px rgba(0,0,0,0.18);
  --shadow-card: 0 4px 20px rgba(0,0,0,0.06);
  --shadow-card-hover: 0 8px 30px rgba(0,0,0,0.10);
  --shadow-lg: 0 20px 60px rgba(0,0,0,0.12);

  /* === 圆角 === */
  --radius-pill: 50px;
  --radius-lg: 16px;
  --radius-md: 12px;
  --radius-sm: 8px;

  /* === 过渡 === */
  --transition: 0.2s;
}

* { box-sizing: border-box; margin: 0; padding: 0; }
html { scrollbar-gutter: stable; -webkit-font-smoothing: antialiased; -moz-osx-font-smoothing: grayscale; }
body { font-family: -apple-system, "Microsoft YaHei", "Segoe UI", sans-serif; background: var(--bg-body); color: var(--text-main); min-height: 100vh; padding-bottom: 36px; }

.container { max-width: 900px; margin: 0 auto; padding: 0 20px; }

/* 顶部标题 */
.app-header { padding: 1.75rem 0 0.75rem; border-bottom: 1px solid var(--border-light); margin-bottom: 0; }
.app-header h1 { font-size: 1.8rem; font-weight: 700; background: linear-gradient(135deg, var(--primary-dark), var(--primary)); background-clip: text; -webkit-background-clip: text; color: transparent; letter-spacing: -0.3px; display: inline-block; }
.app-header .badge-tag { display: inline-flex; gap: 0.5rem; margin-top: 0.4rem; font-size: 0.8rem; color: var(--text-secondary); font-weight: 500; }

/* 标题下方说明 */
.app-desc {
  font-size: 0.82rem; color: var(--text-secondary); line-height: 1.6;
  padding: 0 0 10px;
}
.app-desc p { margin: 0 !important; }
.app-desc p:last-child { margin-bottom: 0 !important; }

/* Tab切换 */
.tabs { display: flex; border-bottom: 2px solid var(--border-light); margin-bottom: 20px; }
.tab { padding: 10px 20px; cursor: pointer; font-size: 15px; color: var(--text-muted); border-bottom: 2px solid transparent; margin-bottom: -2px; transition: color var(--transition), border-color var(--transition); }
.tab:hover { color: var(--primary-light); }
.tab.active { color: var(--primary); border-color: var(--primary); font-weight: 500; }

.panel { display: none; }
.panel.active { display: block; animation: fadeIn 0.3s ease; }
@keyframes fadeIn { from { opacity: 0; transform: translateY(4px); } to { opacity: 1; transform: translateY(0); } }

/* 底部免责声明 */
.footer-note {
  text-align: center;
  font-size: 0.72rem;
  color: var(--text-muted);
  padding: 8px 12px;
  margin-top: 180px;
}