/* ========== CSS 变量 & 重置 ========== */
:root {
  --primary: #4285F4;
  --primary-dark: #3367D6;
  --secondary: #34A853;
  --accent: #FBBC04;
  --danger: #EA4335;
  --text-primary: #1a1a2e;
  --text-secondary: #555;
  --bg-body: #f8f9fc;
  --bg-card: #ffffff;
  --bg-dark: #1a1a2e;
  --shadow-sm: 0 4px 12px rgba(0,0,0,0.06);
  --shadow-md: 0 8px 30px rgba(0,0,0,0.1);
  --shadow-lg: 0 20px 60px rgba(0,0,0,0.15);
  --radius: 16px;
  --radius-sm: 10px;
  --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --font: 'Segoe UI', system-ui, -apple-system, sans-serif;
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html { scroll-behavior: smooth; }

body {
  font-family: var(--font);
  background: var(--bg-body);
  color: var(--text-primary);
  line-height: 1.6;
  overflow-x: hidden;
}

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

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

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

/* ========== 按钮 ========== */
.btn {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 12px 28px; border: none; border-radius: 50px;
  font-size: 1rem; font-weight: 600; cursor: pointer;
  transition: var(--transition); text-decoration: none;
}
.btn-primary { background: var(--primary); color: #fff; }
.btn-primary:hover { background: var(--primary-dark); transform: translateY(-2px); box-shadow: 0 8px 20px rgba(66,133,244,0.35); }
.btn-secondary { background: rgba(255,255,255,0.15); color: #fff; backdrop-filter: blur(10px); border: 1px solid rgba(255,255,255,0.25); }
.btn-secondary:hover { background: rgba(255,255,255,0.25); transform: translateY(-2px); }
.btn-large { padding: 16px 36px; font-size: 1.1rem; }
.btn-block { width: 100%; justify-content: center; }
.btn-logout { background: var(--danger); color: #fff; margin-top: auto; padding: 10px 20px; border-radius: var(--radius-sm); font-size: 0.9rem; }
.btn-logout:hover { background: #c62828; }

/* ========== 导航栏 ========== */
.navbar {
  position: fixed; top: 0; left: 0; width: 100%;
  background: rgba(255,255,255,0.85); backdrop-filter: blur(20px);
  border-bottom: 1px solid rgba(0,0,0,0.05);
  z-index: 1000; transition: var(--transition);
}
.navbar.scrolled { box-shadow: var(--shadow-sm); }
.navbar-inner {
  display: flex; justify-content: space-between; align-items: center;
  height: 70px;
}
.logo { display: flex; align-items: center; gap: 10px; color: var(--text-primary); font-size: 1.3rem; font-weight: 700; }
.logo-icon { color: var(--primary); font-size: 1.6rem; }
.logo-text { background: linear-gradient(135deg, var(--primary), var(--secondary)); -webkit-background-clip: text; -webkit-text-fill-color: transparent; }
.nav-links { display: flex; align-items: center; gap: 32px; }
.nav-links a { color: var(--text-secondary); font-weight: 500; font-size: 0.95rem; position: relative; }
.nav-links a::after {
  content: ''; position: absolute; bottom: -4px; left: 0; width: 0; height: 2px;
  background: var(--primary); transition: var(--transition);
}
.nav-links a:hover::after, .nav-links a.active::after { width: 100%; }
.nav-admin-link { background: var(--primary); color: #fff !important; padding: 6px 16px; border-radius: 50px; font-size: 0.85rem !important; }
.nav-admin-link::after { display: none !important; }
.nav-admin-link:hover { background: var(--primary-dark) !important; }

.menu-toggle {
  display: none; flex-direction: column; gap: 5px; background: none; border: none; cursor: pointer; padding: 8px;
}
.menu-toggle span { display: block; width: 26px; height: 3px; background: var(--text-primary); border-radius: 4px; transition: var(--transition); }

/* ========== 英雄区 ========== */
.hero {
  position: relative; min-height: 100vh;
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  display: flex; align-items: center; padding-top: 70px; overflow: hidden;
}
.hero-content { display: flex; align-items: center; gap: 60px; padding: 80px 0 120px; position: relative; z-index: 2; }
.hero-text { flex: 1; color: #fff; }
.hero-text h1 { font-size: 3.5rem; font-weight: 800; line-height: 1.2; margin-bottom: 16px; }
.hero-text h1 .highlight { background: linear-gradient(135deg, #fbbc04, #ea4335); -webkit-background-clip: text; -webkit-text-fill-color: transparent; }
.subtitle { font-size: 1.2rem; opacity: 0.9; margin-bottom: 36px; max-width: 480px; }
.hero-actions { display: flex; gap: 16px; flex-wrap: wrap; margin-bottom: 40px; }
.hero-stats { display: flex; gap: 32px; font-size: 0.9rem; opacity: 0.85; }
.hero-stats i { margin-right: 6px; }
.hero-image { flex: 1; max-width: 480px; }
.browser-mockup {
  background: #fff; border-radius: var(--radius); overflow: hidden;
  box-shadow: var(--shadow-lg); transform: perspective(1000px) rotateY(-5deg) rotateX(3deg);
  transition: var(--transition);
}
.browser-mockup:hover { transform: perspective(1000px) rotateY(-2deg) rotateX(1deg); }
.browser-bar { display: flex; align-items: center; gap: 8px; padding: 14px 20px; background: #f1f3f4; }
.browser-bar span { width: 12px; height: 12px; border-radius: 50%; }
.browser-bar span:nth-child(1) { background: #fc5f59; }
.browser-bar span:nth-child(2) { background: #fdbc40; }
.browser-bar span:nth-child(3) { background: #33c748; }
.address-bar { flex: 1; background: #fff; border-radius: 6px; padding: 6px 12px; font-size: 0.8rem; color: #888; margin-left: 8px; }
.browser-content { display: flex; flex-direction: column; align-items: center; justify-content: center; padding: 60px 20px; }
.chrome-logo-big { font-size: 5rem; color: var(--primary); margin-bottom: 12px; }
.browser-content p { font-weight: 600; color: #333; font-size: 1.2rem; }

.hero-wave { position: absolute; bottom: -1px; left: 0; width: 100%; line-height: 0; }
.hero-wave svg { display: block; width: 100%; height: 80px; }

/* ========== 通用 section ========== */
.section-header { text-align: center; margin-bottom: 48px; }
.section-header h2 { font-size: 2.2rem; font-weight: 700; margin-bottom: 8px; }
.section-header p { color: var(--text-secondary); font-size: 1.05rem; }

section { padding: 100px 0; }

/* ========== 功能特色 ========== */
.features { background: var(--bg-card); }
.features-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); gap: 28px; }
.feature-card {
  background: var(--bg-body); border-radius: var(--radius); padding: 32px 24px;
  transition: var(--transition); border: 1px solid transparent; text-align: center;
  box-shadow: var(--shadow-sm);
}
.feature-card:hover { transform: translateY(-6px); box-shadow: var(--shadow-md); border-color: var(--primary); }
.feature-icon { width: 64px; height: 64px; background: linear-gradient(135deg, var(--primary), #8b5cf6); border-radius: 16px; display: flex; align-items: center; justify-content: center; margin: 0 auto 20px; color: #fff; font-size: 1.6rem; }
.feature-card h3 { font-size: 1.2rem; margin-bottom: 8px; }
.feature-card p { color: var(--text-secondary); font-size: 0.95rem; }

/* ========== 版本下载 ========== */
.versions { background: var(--bg-body); }
.versions-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); gap: 24px; margin-bottom: 32px; }
.version-card {
  background: var(--bg-card); border-radius: var(--radius); padding: 28px 20px;
  text-align: center; box-shadow: var(--shadow-sm); transition: var(--transition);
  border: 1px solid rgba(0,0,0,0.04);
}
.version-card:hover { transform: translateY(-4px); box-shadow: var(--shadow-md); }
.version-icon { font-size: 2.8rem; color: var(--primary); margin-bottom: 12px; }
.version-card h3 { font-size: 1.3rem; margin-bottom: 4px; }
.version-card .version-desc { color: var(--text-secondary); font-size: 0.9rem; margin-bottom: 16px; }
.version-card .btn-download { margin-top: auto; }
.version-note { text-align: center; font-size: 0.85rem; color: var(--text-secondary); }
.version-note a { color: var(--primary); }

/* ========== FAQ ========== */
.faq { background: var(--bg-card); }
.faq-list { max-width: 740px; margin: 0 auto; }
.faq-item {
  border: 1px solid #eef0f4; border-radius: var(--radius-sm); margin-bottom: 12px;
  overflow: hidden; transition: var(--transition);
}
.faq-item.active { box-shadow: var(--shadow-sm); border-color: var(--primary); }
.faq-question {
  display: flex; justify-content: space-between; align-items: center;
  padding: 18px 24px; cursor: pointer; font-weight: 600; font-size: 1rem;
  background: #fafafa; transition: var(--transition);
}
.faq-question i { transition: var(--transition); color: var(--text-secondary); }
.faq-item.active .faq-question i { transform: rotate(180deg); color: var(--primary); }
.faq-answer { max-height: 0; overflow: hidden; transition: max-height 0.4s ease, padding 0.3s ease; padding: 0 24px; background: #fff; }
.faq-item.active .faq-answer { max-height: 200px; padding: 16px 24px 24px; }
.faq-answer p { color: var(--text-secondary); line-height: 1.8; }

/* ========== 页脚 ========== */
.footer { background: var(--bg-dark); color: #ccc; padding: 60px 0 0; }
.footer-inner { display: grid; grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); gap: 40px; }
.footer-brand .logo { color: #fff; font-size: 1.2rem; margin-bottom: 12px; display: inline-flex; }
.footer-brand p { font-size: 0.9rem; opacity: 0.8; margin-top: 12px; }
.footer-links h4 { color: #fff; margin-bottom: 16px; font-size: 1rem; }
.footer-links a { display: block; color: #aaa; margin-bottom: 8px; font-size: 0.9rem; }
.footer-links a:hover { color: #fff; }
.footer-bottom { text-align: center; padding: 24px 0; margin-top: 40px; border-top: 1px solid rgba(255,255,255,0.08); font-size: 0.85rem; opacity: 0.7; }

/* ========== 后台管理 ========== */
.admin-page { background: #f0f2f5; min-height: 100vh; }
.admin-container { min-height: 100vh; }
.admin-login {
  display: flex; align-items: center; justify-content: center; min-height: 100vh;
  background: linear-gradient(135deg, #667eea, #764ba2);
}
.login-card {
  background: #fff; border-radius: var(--radius); padding: 48px 40px; width: 100%; max-width: 400px;
  box-shadow: var(--shadow-lg);
}
.login-header { text-align: center; margin-bottom: 32px; }
.login-header i { font-size: 3rem; color: var(--primary); }
.login-header h2 { margin: 12px 0 4px; }
.login-header p { color: var(--text-secondary); font-size: 0.9rem; }
.form-group { margin-bottom: 20px; }
.form-group label { display: block; margin-bottom: 6px; font-weight: 500; font-size: 0.9rem; }
.form-group input, .form-group textarea {
  width: 100%; padding: 12px 16px; border: 2px solid #e0e0e0; border-radius: var(--radius-sm);
  font-size: 1rem; transition: var(--transition); background: #fafafa;
}
.form-group input:focus, .form-group textarea:focus { border-color: var(--primary); outline: none; background: #fff; }
.form-group textarea { min-height: 100px; resize: vertical; }
.login-error { color: var(--danger); text-align: center; margin-top: 12px; min-height: 24px; font-size: 0.9rem; }

/* 管理面板 */
.admin-panel { display: flex; min-height: 100vh; }
.admin-nav {
  width: 240px; background: var(--bg-dark); color: #fff; display: flex; flex-direction: column;
  padding: 24px 0; position: sticky; top: 0; height: 100vh;
}
.admin-nav-header { padding: 0 24px 24px; font-size: 1.2rem; font-weight: 700; border-bottom: 1px solid rgba(255,255,255,0.1); margin-bottom: 16px; }
.admin-nav-links { flex: 1; }
.admin-nav-links a { display: block; padding: 12px 24px; color: #aaa; transition: var(--transition); font-size: 0.95rem; }
.admin-nav-links a i { margin-right: 10px; width: 20px; text-align: center; }
.admin-nav-links a:hover, .admin-nav-links a.active { background: rgba(255,255,255,0.08); color: #fff; }
.admin-content { flex: 1; padding: 32px; max-width: calc(100% - 240px); }
.admin-tab-header { display: flex; justify-content: space-between; align-items: center; margin-bottom: 24px; }
.admin-table-wrapper { overflow-x: auto; }
.admin-table { width: 100%; border-collapse: collapse; background: #fff; border-radius: var(--radius-sm); overflow: hidden; box-shadow: var(--shadow-sm); }
.admin-table th, .admin-table td { padding: 14px 18px; text-align: left; border-bottom: 1px solid #f0f0f0; }
.admin-table th { background: #f8f9fc; font-weight: 600; font-size: 0.85rem; color: var(--text-secondary); }
.admin-table td { font-size: 0.9rem; }
.admin-table tr:hover td { background: #fafafa; }
.admin-table .actions { display: flex; gap: 8px; }
.admin-table .btn-sm { padding: 6px 14px; font-size: 0.8rem; border-radius: 6px; }
.btn-edit { background: #e8f0fe; color: var(--primary); }
.btn-edit:hover { background: #d2e3fc; }
.btn-delete { background: #fce8e6; color: var(--danger); }
.btn-delete:hover { background: #f8d7da; }

/* 弹窗 Modal */
.modal-overlay {
  position: fixed; top: 0; left: 0; width: 100%; height: 100%;
  background: rgba(0,0,0,0.5); backdrop-filter: blur(6px);
  display: flex; align-items: center; justify-content: center; z-index: 2000;
}
.modal-card { background: #fff; border-radius: var(--radius); width: 90%; max-width: 500px; max-height: 80vh; overflow-y: auto; box-shadow: var(--shadow-lg); }
.modal-header { display: flex; justify-content: space-between; align-items: center; padding: 24px 28px 0; }
.modal-header h3 { font-size: 1.2rem; }
.modal-close { background: none; border: none; font-size: 1.8rem; cursor: pointer; color: #aaa; transition: var(--transition); }
.modal-close:hover { color: var(--danger); }
#modalBody { padding: 20px 28px; }
.modal-actions { display: flex; gap: 12px; justify-content: flex-end; padding: 20px 28px; border-top: 1px solid #f0f0f0; }

/* ========== 响应式 ========== */
@media (max-width: 992px) {
  .hero-content { flex-direction: column; text-align: center; }
  .hero-text h1 { font-size: 2.8rem; }
  .subtitle { margin: 0 auto 36px; }
  .hero-actions { justify-content: center; }
  .hero-stats { justify-content: center; flex-wrap: wrap; }
  .hero-image { max-width: 360px; }
  .admin-panel { flex-direction: column; }
  .admin-nav { width: 100%; height: auto; position: relative; flex-direction: row; padding: 12px 16px; align-items: center; }
  .admin-nav-header { border: none; padding: 0 16px 0 0; margin: 0; }
  .admin-nav-links { display: flex; gap: 8px; flex: 1; }
  .admin-nav-links a { padding: 8px 14px; border-radius: 6px; font-size: 0.85rem; }
  .btn-logout { margin: 0; }
  .admin-content { max-width: 100%; padding: 20px; }
}

@media (max-width: 768px) {
  .navbar-inner { height: 60px; }
  .nav-links { position: fixed; top: 60px; left: 0; width: 100%; background: rgba(255,255,255,0.98); backdrop-filter: blur(20px); flex-direction: column; padding: 20px; gap: 16px; box-shadow: var(--shadow-md); transform: translateY(-120%); transition: var(--transition); }
  .nav-links.open { transform: translateY(0); }
  .menu-toggle { display: flex; }
  .hero-text h1 { font-size: 2.2rem; }
  .hero-content { padding: 60px 0 80px; }
  .hero-image { max-width: 280px; }
  .features-grid { grid-template-columns: 1fr; }
  .versions-grid { grid-template-columns: 1fr 1fr; }
  section { padding: 60px 0; }
  .section-header h2 { font-size: 1.8rem; }
  .admin-nav { flex-wrap: wrap; }
  .admin-nav-links { order: 3; width: 100%; margin-top: 8px; flex-wrap: wrap; }
}

@media (max-width: 480px) {
  .container { padding: 0 16px; }
  .hero-text h1 { font-size: 1.8rem; }
  .hero-actions { flex-direction: column; align-items: stretch; }
  .hero-stats { flex-direction: column; gap: 12px; align-items: center; }
  .versions-grid { grid-template-columns: 1fr; }
  .login-card { padding: 32px 20px; }
  .modal-card { width: 95%; }
}