/* 91PO官网 - 响应式样式 */
:root {
  --primary: #ff6b00;
  --primary-dark: #e55d00;
  --accent: #7c3aed;
  --accent-light: #a78bfa;
  --bg-dark: #0d0d12;
  --bg-card: #16161f;
  --bg-card-hover: #1e1e2a;
  --text-primary: #f5f5f7;
  --text-secondary: #a0a0b0;
  --text-muted: #6b6b7b;
  --border: #2a2a3a;
  --gradient: linear-gradient(135deg, #ff6b00 0%, #ff3d00 100%);
  --gradient-purple: linear-gradient(135deg, #7c3aed 0%, #a855f7 100%);
  --shadow: 0 4px 24px rgba(0,0,0,0.4);
  --radius: 12px;
  --radius-sm: 8px;
  --max-width: 1200px;
  --header-height: 64px;
}

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

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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  background: var(--bg-dark);
  color: var(--text-primary);
  line-height: 1.7;
  min-height: 100vh;
}

a { color: var(--primary); text-decoration: none; transition: color 0.2s; }
a:hover { color: var(--accent-light); }

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

.container { max-width: var(--max-width); margin: 0 auto; padding: 0 20px; }

/* Header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: rgba(13,13,18,0.95);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  height: var(--header-height);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: var(--header-height);
}

.logo-link {
  display: flex;
  align-items: center;
  gap: 12px;
  color: var(--text-primary);
}

.logo-link img { width: 40px; height: 40px; border-radius: 10px; }

.logo-text { font-size: 1.25rem; font-weight: 700; }
.logo-text span { color: var(--primary); }

.nav-main { display: flex; gap: 8px; list-style: none; }

.nav-main a {
  color: var(--text-secondary);
  padding: 8px 16px;
  border-radius: var(--radius-sm);
  font-size: 0.95rem;
  transition: all 0.2s;
}

.nav-main a:hover,
.nav-main a.active {
  color: var(--text-primary);
  background: var(--bg-card);
}

.nav-main a.active { color: var(--primary); }

.btn-download {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: var(--gradient);
  color: #fff !important;
  padding: 10px 24px;
  border-radius: 50px;
  font-weight: 600;
  font-size: 0.95rem;
  border: none;
  cursor: pointer;
  transition: transform 0.2s, box-shadow 0.2s;
  white-space: nowrap;
}

.btn-download:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(255,107,0,0.4);
  color: #fff !important;
}

.menu-toggle {
  display: none;
  background: none;
  border: none;
  color: var(--text-primary);
  font-size: 1.5rem;
  cursor: pointer;
  padding: 8px;
}

/* Hero */
.hero {
  padding: 60px 0 80px;
  background: radial-gradient(ellipse at 50% 0%, rgba(124,58,237,0.15) 0%, transparent 60%),
              radial-gradient(ellipse at 80% 50%, rgba(255,107,0,0.08) 0%, transparent 50%);
}

.hero-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 48px;
  align-items: center;
}

.hero-content h1 {
  font-size: 2.5rem;
  line-height: 1.3;
  margin-bottom: 20px;
  background: linear-gradient(135deg, #fff 0%, #ccc 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-content h1 em {
  font-style: normal;
  background: var(--gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-desc {
  font-size: 1.1rem;
  color: var(--text-secondary);
  margin-bottom: 32px;
  max-width: 520px;
}

.hero-btns { display: flex; gap: 16px; flex-wrap: wrap; margin-bottom: 32px; }

.btn-secondary {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: var(--bg-card);
  color: var(--text-primary) !important;
  padding: 10px 24px;
  border-radius: 50px;
  font-weight: 600;
  border: 1px solid var(--border);
  transition: all 0.2s;
}

.btn-secondary:hover {
  background: var(--bg-card-hover);
  border-color: var(--primary);
  color: var(--primary) !important;
}

.hero-features {
  display: flex;
  gap: 24px;
  flex-wrap: wrap;
}

.hero-feature {
  display: flex;
  align-items: center;
  gap: 8px;
  color: var(--text-secondary);
  font-size: 0.9rem;
}

.hero-feature::before {
  content: "✓";
  color: var(--primary);
  font-weight: bold;
}

.hero-image {
  position: relative;
  display: flex;
  justify-content: center;
}

.hero-image img {
  max-width: 320px;
  border-radius: 24px;
  box-shadow: var(--shadow), 0 0 60px rgba(124,58,237,0.2);
}

.hero-image::after {
  content: "";
  position: absolute;
  inset: -20px;
  border-radius: 32px;
  background: var(--gradient-purple);
  opacity: 0.1;
  z-index: -1;
  filter: blur(40px);
}

/* Section */
.section { padding: 80px 0; }
.section-alt { background: var(--bg-card); }

.section-header {
  text-align: center;
  margin-bottom: 48px;
}

.section-header h2 {
  font-size: 2rem;
  margin-bottom: 12px;
}

.section-header p {
  color: var(--text-secondary);
  max-width: 600px;
  margin: 0 auto;
}

/* Feature Cards */
.feature-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.feature-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px;
  transition: all 0.3s;
}

.section-alt .feature-card { background: var(--bg-dark); }

.feature-card:hover {
  border-color: var(--primary);
  transform: translateY(-4px);
  box-shadow: var(--shadow);
}

.feature-icon {
  width: 48px;
  height: 48px;
  background: var(--gradient);
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  margin-bottom: 16px;
}

.feature-card h3 { font-size: 1.15rem; margin-bottom: 10px; }
.feature-card p { color: var(--text-secondary); font-size: 0.95rem; }

/* Screenshot Gallery */
.gallery-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
}

.gallery-item {
  background: var(--bg-card);
  border-radius: var(--radius);
  overflow: hidden;
  border: 1px solid var(--border);
  transition: all 0.3s;
}

.gallery-item:hover {
  border-color: var(--accent);
  transform: scale(1.02);
}

.gallery-item img { width: 100%; aspect-ratio: 9/16; object-fit: cover; }

.gallery-caption {
  padding: 12px 16px;
  font-size: 0.9rem;
  color: var(--text-secondary);
  text-align: center;
}

/* Category Tags */
.category-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin: 24px 0;
}

.tag {
  background: var(--bg-card);
  border: 1px solid var(--border);
  color: var(--text-secondary);
  padding: 6px 16px;
  border-radius: 50px;
  font-size: 0.85rem;
  transition: all 0.2s;
}

.tag:hover {
  border-color: var(--primary);
  color: var(--primary);
}

/* Content Article */
.content-article {
  max-width: 860px;
  margin: 0 auto;
}

.content-article h2 {
  font-size: 1.6rem;
  margin: 40px 0 16px;
  padding-bottom: 8px;
  border-bottom: 2px solid var(--primary);
}

.content-article h3 {
  font-size: 1.25rem;
  margin: 28px 0 12px;
  color: var(--accent-light);
}

.content-article p {
  color: var(--text-secondary);
  margin-bottom: 16px;
  text-align: justify;
}

.content-article ul, .content-article ol {
  color: var(--text-secondary);
  margin: 16px 0 16px 24px;
}

.content-article li { margin-bottom: 8px; }

.content-article a { text-decoration: underline; text-underline-offset: 3px; }

/* Steps */
.steps {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
  margin: 32px 0;
}

.step-item {
  text-align: center;
  padding: 24px 16px;
  background: var(--bg-card);
  border-radius: var(--radius);
  border: 1px solid var(--border);
}

.step-num {
  width: 40px;
  height: 40px;
  background: var(--gradient);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  margin: 0 auto 12px;
}

.step-item h4 { margin-bottom: 8px; font-size: 1rem; }
.step-item p { color: var(--text-secondary); font-size: 0.85rem; }

/* FAQ */
.faq-list { max-width: 800px; margin: 0 auto; }

.faq-item {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  margin-bottom: 12px;
  overflow: hidden;
}

.faq-question {
  padding: 20px 24px;
  font-weight: 600;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  transition: background 0.2s;
}

.faq-question:hover { background: var(--bg-card-hover); }

.faq-question::after {
  content: "+";
  font-size: 1.25rem;
  color: var(--primary);
  transition: transform 0.3s;
}

.faq-item.open .faq-question::after { transform: rotate(45deg); }

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s ease;
}

.faq-item.open .faq-answer { max-height: 500px; }

.faq-answer p {
  padding: 0 24px 20px;
  color: var(--text-secondary);
}

/* CTA */
.cta-section {
  text-align: center;
  padding: 80px 0;
  background: radial-gradient(ellipse at center, rgba(255,107,0,0.1) 0%, transparent 70%);
}

.cta-section h2 { font-size: 2rem; margin-bottom: 16px; }
.cta-section p { color: var(--text-secondary); margin-bottom: 32px; }

/* Page Header */
.page-header {
  padding: 48px 0 32px;
  text-align: center;
  background: var(--bg-card);
  border-bottom: 1px solid var(--border);
}

.page-header h1 { font-size: 2rem; margin-bottom: 8px; }
.page-header p { color: var(--text-secondary); }

.breadcrumb {
  display: flex;
  justify-content: center;
  gap: 8px;
  font-size: 0.9rem;
  color: var(--text-muted);
  margin-top: 12px;
}

.breadcrumb a { color: var(--text-secondary); }
.breadcrumb span { color: var(--text-muted); }

/* Legal Page */
.legal-content {
  max-width: 860px;
  margin: 0 auto;
  padding: 48px 20px 80px;
}

.legal-content h2 {
  font-size: 1.4rem;
  margin: 32px 0 12px;
  color: var(--text-primary);
}

.legal-content h3 {
  font-size: 1.15rem;
  margin: 24px 0 10px;
  color: var(--accent-light);
}

.legal-content p, .legal-content li {
  color: var(--text-secondary);
  margin-bottom: 12px;
  line-height: 1.8;
}

.legal-content ul, .legal-content ol { margin: 12px 0 12px 24px; }

.legal-content .update-date {
  color: var(--text-muted);
  font-size: 0.9rem;
  margin-bottom: 32px;
}

/* Error Pages */
.error-page {
  min-height: 80vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 40px 20px;
}

.error-code {
  font-size: 8rem;
  font-weight: 800;
  background: var(--gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  line-height: 1;
  margin-bottom: 16px;
}

.error-page h1 { font-size: 1.75rem; margin-bottom: 12px; }
.error-page p { color: var(--text-secondary); margin-bottom: 32px; max-width: 480px; margin-left: auto; margin-right: auto; }

/* Footer */
.site-footer {
  background: var(--bg-card);
  border-top: 1px solid var(--border);
  padding: 48px 0 24px;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 40px;
  margin-bottom: 40px;
}

.footer-brand img { width: 48px; border-radius: 12px; margin-bottom: 12px; }
.footer-brand p { color: var(--text-muted); font-size: 0.9rem; max-width: 280px; }

.footer-col h4 {
  font-size: 0.95rem;
  margin-bottom: 16px;
  color: var(--text-primary);
}

.footer-col ul { list-style: none; }
.footer-col li { margin-bottom: 8px; }
.footer-col a { color: var(--text-muted); font-size: 0.9rem; }
.footer-col a:hover { color: var(--primary); }

.footer-bottom {
  border-top: 1px solid var(--border);
  padding-top: 24px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 12px;
}

.footer-bottom p { color: var(--text-muted); font-size: 0.85rem; }

.footer-links { display: flex; gap: 20px; }
.footer-links a { color: var(--text-muted); font-size: 0.85rem; }

/* Internal Links Box */
.internal-links {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  margin: 32px 0;
}

.internal-links h3 {
  font-size: 1.1rem;
  margin-bottom: 16px;
  color: var(--primary);
}

.internal-links ul {
  list-style: none;
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 8px;
}

.internal-links a {
  color: var(--text-secondary);
  font-size: 0.9rem;
  display: flex;
  align-items: center;
  gap: 6px;
}

.internal-links a::before {
  content: "→";
  color: var(--primary);
}

/* Mobile Nav */
@media (max-width: 992px) {
  .hero-grid { grid-template-columns: 1fr; text-align: center; }
  .hero-desc { margin: 0 auto 32px; }
  .hero-btns { justify-content: center; }
  .hero-features { justify-content: center; }
  .hero-image { order: -1; }
  .hero-image img { max-width: 260px; }
  .feature-grid { grid-template-columns: repeat(2, 1fr); }
  .gallery-grid { grid-template-columns: repeat(2, 1fr); }
  .steps { grid-template-columns: repeat(2, 1fr); }
  .footer-grid { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 768px) {
  .menu-toggle { display: block; }

  .nav-main {
    display: none;
    position: absolute;
    top: var(--header-height);
    left: 0;
    right: 0;
    background: var(--bg-card);
    flex-direction: column;
    padding: 16px;
    border-bottom: 1px solid var(--border);
  }

  .nav-main.open { display: flex; }

  .header-inner .btn-download { display: none; }

  .hero-content h1 { font-size: 1.75rem; }
  .section { padding: 48px 0; }
  .section-header h2 { font-size: 1.5rem; }
  .feature-grid { grid-template-columns: 1fr; }
  .gallery-grid { grid-template-columns: repeat(2, 1fr); gap: 12px; }
  .steps { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr; }
  .footer-bottom { flex-direction: column; text-align: center; }
  .internal-links ul { grid-template-columns: 1fr; }
}

@media (max-width: 480px) {
  .hero-content h1 { font-size: 1.5rem; }
  .gallery-grid { grid-template-columns: 1fr 1fr; }
}