/* ===== 爱思助手品牌色系 ===== */
:root {
  --primary: #007AFF;
  --primary-dark: #0066D6;
  --primary-light: #EAF2FF;
  --gradient-start: #A048ED;
  --gradient-end: #007AFF;
  --secondary: #236EE7;
  --bg: #F5F5F7;
  --white: #FFFFFF;
  --text: #333333;
  --text-secondary: #808080;
  --text-light: #999999;
  --border: #E5E5E5;
  --success: #0EA400;
  --warning: #E58530;
  --danger: #FF4D4F;
  --shadow: 0 2px 12px rgba(0,0,0,0.08);
}

/* ===== Reset & Base ===== */
* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}
a { text-decoration: none; color: var(--primary); transition: color 0.2s; }
a:hover { color: var(--primary-dark); }
img { max-width: 100%; height: auto; }
ul { list-style: none; }

/* ===== Container ===== */
.container { max-width: 1200px; margin: 0 auto; padding: 0 20px; }

/* ===== Header ===== */
.header {
  background: var(--white);
  box-shadow: 0 1px 4px rgba(0,0,0,0.06);
  position: sticky; top: 0; z-index: 1000;
}
.header-inner {
  display: flex; align-items: center; justify-content: space-between;
  max-width: 1200px; margin: 0 auto; padding: 0 20px; height: 64px;
}
.logo { display: flex; align-items: center; gap: 10px; }
.logo img { width: 42px; height: 42px; }
.logo span {
  font-size: 20px; font-weight: 700;
  background: linear-gradient(135deg, var(--gradient-start), var(--gradient-end));
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
  background-clip: text;
}
.nav { display: flex; gap: 4px; }
.nav a {
  display: block; padding: 8px 18px; color: var(--text); font-size: 15px;
  border-radius: 8px; transition: all 0.2s;
  font-weight: 500;
}
.nav a:hover, .nav a.active {
  background: var(--primary-light); color: var(--primary);
}

/* ===== Hero ===== */
.hero {
  background: linear-gradient(135deg, #A048ED 0%, #007AFF 100%);
  padding: 80px 0; text-align: center; color: var(--white);
  position: relative; overflow: hidden;
}
.hero::before {
  content: ''; position: absolute; inset: 0;
  background: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 1440 320"><path fill="rgba(255,255,255,0.05)" d="M0,160L48,176C96,192,192,224,288,208C384,192,480,128,576,133.3C672,139,768,213,864,224C960,235,1056,181,1152,165.3C1248,149,1344,171,1392,181.3L1440,192L1440,320L1392,320C1344,320,1248,320,1152,320C1056,320,960,320,864,320C768,320,672,320,576,320C480,320,384,320,288,320C192,320,96,320,48,320L0,320Z"/></svg>') no-repeat bottom;
  background-size: cover;
}
.hero h1 { font-size: 42px; font-weight: 700; margin-bottom: 16px; position: relative; }
.hero p { font-size: 18px; opacity: 0.9; max-width: 700px; margin: 0 auto 32px; position: relative; }
.hero-btns { display: flex; gap: 16px; justify-content: center; flex-wrap: wrap; position: relative; }
.btn {
  display: inline-block; padding: 12px 32px; border-radius: 10px; font-size: 16px;
  font-weight: 600; transition: all 0.3s; cursor: pointer; border: none;
}
.btn-primary {
  background: var(--white); color: var(--primary);
  box-shadow: 0 4px 16px rgba(0,0,0,0.15);
}
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 6px 24px rgba(0,0,0,0.2); color: var(--primary); }
.btn-outline {
  background: transparent; color: var(--white);
  border: 2px solid rgba(255,255,255,0.5);
}
.btn-outline:hover { background: rgba(255,255,255,0.1); border-color: var(--white); color: var(--white); }
.btn-blue {
  background: var(--primary); color: var(--white);
  box-shadow: 0 4px 16px rgba(0,122,255,0.35);
}
.btn-blue:hover { background: var(--primary-dark); transform: translateY(-2px); box-shadow: 0 6px 24px rgba(0,122,255,0.45); color: var(--white); }

/* ===== Section ===== */
.section { padding: 80px 0; }
.section-gray { background: var(--white); }
.section-title {
  text-align: center; margin-bottom: 48px;
}
.section-title h2 {
  font-size: 32px; font-weight: 700; color: var(--text); margin-bottom: 12px;
}
.section-title p { font-size: 16px; color: var(--text-secondary); }

/* ===== Feature Cards ===== */
.features-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); gap: 24px; }
.feature-card {
  background: var(--white); border-radius: 16px; padding: 32px 24px;
  box-shadow: var(--shadow); transition: all 0.3s; text-align: center;
}
.feature-card:hover { transform: translateY(-4px); box-shadow: 0 8px 30px rgba(0,0,0,0.12); }
.feature-icon {
  width: 64px; height: 64px; margin: 0 auto 20px;
  background: var(--primary-light); border-radius: 16px;
  display: flex; align-items: center; justify-content: center; font-size: 28px;
}
.feature-card h3 { font-size: 18px; margin-bottom: 10px; color: var(--text); }
.feature-card p { font-size: 14px; color: var(--text-secondary); line-height: 1.6; }

/* ===== Steps ===== */
.steps { display: grid; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); gap: 24px; }
.step {
  background: var(--white); border-radius: 16px; padding: 32px 24px;
  box-shadow: var(--shadow); text-align: center; position: relative;
}
.step-num {
  width: 48px; height: 48px; border-radius: 50%;
  background: linear-gradient(135deg, var(--primary), var(--gradient-start));
  color: var(--white); font-size: 22px; font-weight: 700;
  display: flex; align-items: center; justify-content: center;
  margin: 0 auto 16px;
}
.step h3 { font-size: 17px; margin-bottom: 8px; }
.step p { font-size: 14px; color: var(--text-secondary); }

/* ===== Download Cards ===== */
.download-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); gap: 24px; }
.download-card {
  background: var(--white); border-radius: 16px; padding: 32px 24px;
  box-shadow: var(--shadow); transition: all 0.3s; text-align: center;
}
.download-card:hover { transform: translateY(-4px); box-shadow: 0 8px 30px rgba(0,0,0,0.12); }
.download-card.featured {
  border: 2px solid var(--primary);
  position: relative;
}
.download-card.featured::before {
  content: '推荐'; position: absolute; top: 12px; right: 12px;
  background: linear-gradient(135deg, var(--primary), var(--gradient-start));
  color: var(--white); font-size: 12px; padding: 4px 12px; border-radius: 20px;
}
.download-icon { font-size: 40px; margin-bottom: 16px; }
.download-card h3 { font-size: 20px; margin-bottom: 8px; }
.download-card .ver { color: var(--text-secondary); font-size: 14px; margin-bottom: 8px; }
.download-card .date { color: var(--text-light); font-size: 13px; margin-bottom: 20px; }
.download-card .btn { width: 100%; }

/* ===== FAQ ===== */
.faq-list { max-width: 800px; margin: 0 auto; }
.faq-item {
  background: var(--white); border-radius: 12px; margin-bottom: 12px;
  box-shadow: var(--shadow); overflow: hidden;
}
.faq-q {
  padding: 20px 24px; cursor: pointer; font-weight: 600; font-size: 16px;
  display: flex; justify-content: space-between; align-items: center;
  transition: background 0.2s;
}
.faq-q:hover { background: var(--primary-light); }
.faq-a {
  padding: 0 24px 20px; font-size: 15px; color: var(--text-secondary);
  line-height: 1.8; display: none;
}
.faq-item.open .faq-a { display: block; }
.faq-arrow { transition: transform 0.3s; color: var(--text-light); }
.faq-item.open .faq-arrow { transform: rotate(180deg); }

/* ===== Stats ===== */
.stats {
  background: linear-gradient(135deg, var(--primary), #667eea);
  padding: 60px 0; color: var(--white); text-align: center;
}
.stats-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(180px, 1fr)); gap: 32px; }
.stat h3 { font-size: 40px; font-weight: 700; }
.stat p { font-size: 15px; opacity: 0.85; margin-top: 4px; }

/* ===== Platform Tags ===== */
.platform-tags { display: flex; flex-wrap: wrap; gap: 10px; justify-content: center; margin-bottom: 32px; }
.platform-tag {
  display: inline-block; padding: 8px 20px; background: var(--white);
  border-radius: 24px; font-size: 14px; font-weight: 500; color: var(--text);
  box-shadow: var(--shadow); transition: all 0.2s;
}
.platform-tag:hover, .platform-tag.active {
  background: var(--primary); color: var(--white); transform: translateY(-2px);
}

/* ===== Breadcrumb ===== */
.breadcrumb { padding: 16px 0; font-size: 14px; color: var(--text-light); }
.breadcrumb a { color: var(--text-secondary); }
.breadcrumb span { color: var(--text); }

/* ===== Page Hero (inner) ===== */
.page-hero {
  background: linear-gradient(135deg, var(--primary), #667eea);
  padding: 60px 0; text-align: center; color: var(--white);
}
.page-hero h1 { font-size: 36px; font-weight: 700; margin-bottom: 12px; }
.page-hero p { font-size: 16px; opacity: 0.9; }

/* ===== Article Content ===== */
.article { max-width: 800px; margin: 0 auto; }
.article h2 { font-size: 24px; margin: 32px 0 16px; color: var(--text); }
.article h3 { font-size: 18px; margin: 24px 0 12px; }
.article p { margin-bottom: 14px; color: var(--text-secondary); line-height: 1.8; }
.article ul { margin: 16px 0; padding-left: 24px; }
.article ul li { list-style: disc; margin-bottom: 8px; color: var(--text-secondary); line-height: 1.7; }
.article .tip-box {
  background: var(--primary-light); border-left: 4px solid var(--primary);
  padding: 16px 20px; border-radius: 0 8px 8px 0; margin: 20px 0;
  font-size: 14px; color: var(--text);
}
.article .warn-box {
  background: #FFF7E6; border-left: 4px solid var(--warning);
  padding: 16px 20px; border-radius: 0 8px 8px 0; margin: 20px 0;
  font-size: 14px;
}

/* ===== Tutorial List ===== */
.tutorial-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(340px, 1fr)); gap: 24px; }
.tutorial-card {
  background: var(--white); border-radius: 16px; overflow: hidden;
  box-shadow: var(--shadow); transition: all 0.3s; display: flex;
}
.tutorial-card:hover { transform: translateY(-4px); box-shadow: 0 8px 30px rgba(0,0,0,0.12); }
.tutorial-img {
  width: 140px; min-height: 140px; background: linear-gradient(135deg, var(--primary-light), #E8F6FC);
  display: flex; align-items: center; justify-content: center;
  font-size: 48px; flex-shrink: 0;
}
.tutorial-body { padding: 20px; flex: 1; }
.tutorial-body h3 { font-size: 17px; margin-bottom: 8px; line-height: 1.4; }
.tutorial-body p { font-size: 13px; color: var(--text-light); margin-bottom: 12px; }
.tutorial-body .tag {
  display: inline-block; padding: 3px 10px; background: var(--primary-light);
  color: var(--primary); border-radius: 12px; font-size: 12px; font-weight: 500;
}

/* ===== Contact ===== */
.contact-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 40px; }
.contact-info h2 { font-size: 28px; margin-bottom: 16px; }
.contact-item { display: flex; align-items: center; gap: 12px; margin-bottom: 16px; color: var(--text-secondary); }
.contact-icon { font-size: 24px; }
.contact-form { background: var(--white); padding: 32px; border-radius: 16px; box-shadow: var(--shadow); }
.form-group { margin-bottom: 20px; }
.form-group label { display: block; font-weight: 500; margin-bottom: 6px; font-size: 14px; }
.form-group input, .form-group textarea, .form-group select {
  width: 100%; padding: 10px 14px; border: 1px solid var(--border);
  border-radius: 8px; font-size: 15px; transition: border-color 0.2s;
  font-family: inherit;
}
.form-group input:focus, .form-group textarea:focus {
  outline: none; border-color: var(--primary); box-shadow: 0 0 0 3px rgba(0,122,255,0.1);
}
.form-group textarea { min-height: 120px; resize: vertical; }

/* ===== Sitemap ===== */
.sitemap { display: grid; grid-template-columns: repeat(auto-fit, minmax(250px, 1fr)); gap: 32px; }
.sitemap-col h3 { font-size: 18px; margin-bottom: 12px; color: var(--primary); }
.sitemap-col ul li { margin-bottom: 8px; }
.sitemap-col ul li a { font-size: 14px; color: var(--text-secondary); }
.sitemap-col ul li a:hover { color: var(--primary); }

/* ===== Footer ===== */
.footer {
  background: #1a1a2e; color: rgba(255,255,255,0.7); padding: 48px 0 24px;
}
.footer-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); gap: 32px; margin-bottom: 32px; }
.footer-col h3 { color: var(--white); font-size: 16px; margin-bottom: 16px; }
.footer-col ul li { margin-bottom: 10px; }
.footer-col ul li a { color: rgba(255,255,255,0.6); font-size: 14px; transition: color 0.2s; }
.footer-col ul li a:hover { color: var(--white); }
.footer-bottom {
  border-top: 1px solid rgba(255,255,255,0.1); padding-top: 24px;
  text-align: center; font-size: 13px;
}

/* ===== Responsive ===== */
@media (max-width: 768px) {
  .header-inner { flex-direction: column; height: auto; padding: 12px 16px; gap: 12px; }
  .nav { flex-wrap: wrap; justify-content: center; }
  .nav a { font-size: 13px; padding: 6px 12px; }
  .hero { padding: 48px 16px; }
  .hero h1 { font-size: 28px; }
  .hero p { font-size: 15px; }
  .contact-grid { grid-template-columns: 1fr; }
  .tutorial-card { flex-direction: column; }
  .tutorial-img { width: 100%; height: 120px; min-height: auto; }
  .section { padding: 48px 0; }
  .section-title h2 { font-size: 24px; }
  .page-hero { padding: 40px 16px; }
  .page-hero h1 { font-size: 26px; }
}

/* ===== Animations ===== */
@keyframes fadeInUp {
  from { opacity: 0; transform: translateY(20px); }
  to { opacity: 1; transform: translateY(0); }
}
.animate { animation: fadeInUp 0.6s ease-out; }

/* ===== Keyword section (SEO) ===== */
.keyword-cloud { text-align: center; padding: 40px 0; }
.keyword-cloud a {
  display: inline-block; padding: 6px 16px; margin: 4px;
  background: var(--white); border-radius: 20px; font-size: 14px;
  color: var(--text-secondary); box-shadow: 0 1px 4px rgba(0,0,0,0.06);
  transition: all 0.2s;
}
.keyword-cloud a:hover { background: var(--primary); color: var(--white); }