/* === HelloGPT Download Site - Dark Tech Theme (Warm Orange) === */
:root {
  --bg: #0F172A;
  --card: #1E293B;
  --card-hover: #253249;
  --border: #334155;
  --text: #E2E8F0;
  --text-muted: #94A3B8;
  --text-dim: #64748B;
  --primary: #F59E0B;
  --primary-dark: #D97706;
  --primary-glow: rgba(245, 158, 11, 0.25);
  --gradient: linear-gradient(135deg, #F59E0B, #EA580C);
  --success: #10B981;
  --danger: #EF4444;
  --radius: 12px;
  --radius-sm: 8px;
  --shadow: 0 4px 24px rgba(0,0,0,0.3);
  --transition: 0.25s ease;
  --max-w: 1200px;
  --font: 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', system-ui, -apple-system, sans-serif;
  --font-mono: 'Cascadia Code', 'Fira Code', 'JetBrains Mono', 'Consolas', monospace;
}

/* === Reset & Base === */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; font-size: 16px; }
body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--font);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

/* === Typography === */
h1 { font-size: 2.5rem; font-weight: 800; line-height: 1.2; background: var(--gradient); -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text; }
h2 { font-size: 1.75rem; font-weight: 700; color: var(--text); margin: 2rem 0 1rem; position: relative; padding-bottom: 0.75rem; }
h2::after { content: ''; position: absolute; bottom: 0; left: 0; width: 60px; height: 3px; background: var(--gradient); border-radius: 2px; }
h3 { font-size: 1.25rem; font-weight: 600; color: var(--primary); margin: 1.5rem 0 0.75rem; }
h4 { font-size: 1.1rem; font-weight: 600; color: var(--text); margin: 1rem 0 0.5rem; }
p { margin-bottom: 1rem; color: var(--text-muted); }
a { color: var(--primary); text-decoration: none; transition: color var(--transition); }
a:hover { color: var(--primary-dark); text-decoration: underline; }
strong { color: var(--text); font-weight: 600; }
ul, ol { margin: 0.5rem 0 1rem 1.5rem; color: var(--text-muted); }
li { margin-bottom: 0.5rem; }
code { font-family: var(--font-mono); background: rgba(245,158,11,0.1); color: var(--primary); padding: 0.15em 0.4em; border-radius: 4px; font-size: 0.9em; }
pre { background: #0F172A; border: 1px solid var(--border); border-radius: var(--radius); padding: 1.25rem; overflow-x: auto; margin: 1rem 0; }
pre code { background: none; padding: 0; color: var(--text); }
blockquote { border-left: 4px solid var(--primary); padding: 0.75rem 1.25rem; margin: 1rem 0; background: rgba(245,158,11,0.05); border-radius: 0 var(--radius-sm) var(--radius-sm) 0; color: var(--text-muted); font-style: italic; }
img { max-width: 100%; height: auto; border-radius: var(--radius); }
hr { border: none; border-top: 1px solid var(--border); margin: 2rem 0; }

/* === Layout === */
.container { max-width: var(--max-w); margin: 0 auto; padding: 0 1.5rem; }
.section { padding: 3rem 0; }
.section-alt { background: rgba(30,41,59,0.5); }

/* === Header / Navigation === */
.site-header {
  background: rgba(15,23,42,0.95);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 100;
}
.nav { display: flex; align-items: center; justify-content: space-between; height: 64px; gap: 2rem; max-width: var(--max-w); margin: 0 auto; padding: 0 1.5rem; }
.nav-brand { display: flex; align-items: center; gap: 0.5rem; font-size: 1.25rem; font-weight: 700; color: var(--text); white-space: nowrap; }
.nav-brand svg { width: 32px; height: 32px; }
.nav-links { display: flex; gap: 1.5rem; list-style: none; margin: 0; }
.nav-links a { color: var(--text-muted); font-size: 0.9rem; font-weight: 500; transition: color var(--transition); }
.nav-links a:hover { color: var(--primary); text-decoration: none; }
.nav-cta {
  background: var(--gradient);
  color: #fff !important;
  padding: 0.5rem 1.25rem;
  border-radius: 50px;
  font-weight: 600;
  font-size: 0.9rem;
  transition: transform var(--transition), box-shadow var(--transition) !important;
}
.nav-cta:hover { transform: translateY(-1px); box-shadow: 0 4px 20px var(--primary-glow); text-decoration: none !important; }
.mobile-toggle { display: none; background: none; border: none; color: var(--text); font-size: 1.5rem; cursor: pointer; }

/* === Hero === */
.hero { padding: 5rem 0 3rem; text-align: center; position: relative; overflow: hidden; }
.hero::before {
  content: '';
  position: absolute;
  top: -50%;
  left: -50%;
  width: 200%;
  height: 200%;
  background: radial-gradient(ellipse at center, var(--primary-glow) 0%, transparent 50%);
  pointer-events: none;
}
.hero-content { position: relative; z-index: 1; }
.hero h1 { font-size: 3rem; margin-bottom: 1rem; }
.hero p { font-size: 1.2rem; color: var(--text-muted); max-width: 700px; margin: 0 auto 2rem; }
.hero-cta {
  display: inline-block;
  background: var(--gradient);
  color: #fff;
  padding: 0.9rem 2.5rem;
  border-radius: 50px;
  font-size: 1.1rem;
  font-weight: 700;
  text-decoration: none;
  transition: transform var(--transition), box-shadow var(--transition);
}
.hero-cta:hover { transform: translateY(-2px); box-shadow: 0 8px 32px var(--primary-glow); text-decoration: none; color: #fff; }
.hero-badge {
  display: inline-flex; align-items: center; gap: 0.5rem;
  background: rgba(16,185,129,0.1); color: var(--success);
  padding: 0.35rem 1rem; border-radius: 50px; font-size: 0.85rem;
  margin-bottom: 1.5rem;
}

/* === Cards Grid === */
.cards-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); gap: 1.5rem; }
.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.75rem;
  transition: transform var(--transition), box-shadow var(--transition), border-color var(--transition);
  position: relative;
}
.card:hover { transform: translateY(-3px); box-shadow: var(--shadow); border-color: var(--primary); }
.card-icon { width: 48px; height: 48px; background: rgba(245,158,11,0.1); border-radius: var(--radius-sm); display: flex; align-items: center; justify-content: center; margin-bottom: 1rem; font-size: 1.5rem; color: var(--primary); }
.card h3 { margin-top: 0; }
.card p { color: var(--text-muted); font-size: 0.95rem; margin-bottom: 0; }

/* === Download Cards === */
.download-cards { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 1.25rem; }
.download-card {
  background: var(--card);
  border: 2px solid var(--border);
  border-radius: var(--radius);
  padding: 1.75rem;
  text-align: center;
  transition: all var(--transition);
  position: relative;
}
.download-card:hover { border-color: var(--primary); transform: translateY(-2px); box-shadow: 0 4px 24px rgba(245,158,11,0.15); }
.download-card.featured { border-color: var(--primary); background: linear-gradient(135deg, rgba(245,158,11,0.08), var(--card)); }
.download-card.featured::before {
  content: '🔥 推荐';
  position: absolute; top: -12px; left: 50%; transform: translateX(-50%);
  background: var(--gradient); color: #fff; padding: 0.2rem 1rem;
  border-radius: 50px; font-size: 0.75rem; font-weight: 700; white-space: nowrap;
}
.download-card-icon { font-size: 2.5rem; margin-bottom: 0.75rem; display: block; }
.download-card h3 { margin: 0.5rem 0; font-size: 1.1rem; color: var(--text); }
.download-card .meta { font-size: 0.8rem; color: var(--text-dim); margin-bottom: 1rem; }
.download-card .btn {
  display: inline-block;
  background: var(--gradient);
  color: #fff;
  padding: 0.6rem 1.5rem;
  border-radius: 50px;
  font-weight: 600;
  font-size: 0.9rem;
  transition: all var(--transition);
}
.download-card .btn:hover { transform: translateY(-1px); box-shadow: 0 4px 16px var(--primary-glow); text-decoration: none; color: #fff; }

/* === Article Cards === */
.article-cards { display: grid; grid-template-columns: repeat(auto-fit, minmax(320px, 1fr)); gap: 1.5rem; }
.article-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  transition: all var(--transition);
}
.article-card:hover { transform: translateY(-3px); box-shadow: var(--shadow); border-color: var(--primary); }
.article-card-image { width: 100%; height: 180px; object-fit: cover; }
.article-card-body { padding: 1.5rem; }
.article-card-body h3 { margin: 0 0 0.5rem; font-size: 1.15rem; }
.article-card-body h3 a { color: var(--text); }
.article-card-body h3 a:hover { color: var(--primary); text-decoration: none; }
.article-card-body p { font-size: 0.9rem; color: var(--text-muted); margin-bottom: 1rem; }
.article-card-body .tag { display: inline-block; background: rgba(245,158,11,0.1); color: var(--primary); padding: 0.2rem 0.75rem; border-radius: 50px; font-size: 0.8rem; }

/* === FAQ Accordion === */
.faq-list { max-width: 800px; margin: 0 auto; }
.faq-item { background: var(--card); border: 1px solid var(--border); border-radius: var(--radius); margin-bottom: 1rem; overflow: hidden; }
.faq-question {
  width: 100%; background: none; border: none; color: var(--text);
  padding: 1.25rem; font-size: 1rem; text-align: left; cursor: pointer;
  display: flex; justify-content: space-between; align-items: center;
  font-weight: 600; font-family: var(--font); transition: color var(--transition);
}
.faq-question:hover { color: var(--primary); }
.faq-question::after { content: '▾'; font-size: 1.2rem; color: var(--primary); transition: transform var(--transition); }
.faq-item.open .faq-question::after { transform: rotate(180deg); }
.faq-answer { padding: 0 1.25rem 1.25rem; color: var(--text-muted); font-size: 0.95rem; display: none; }
.faq-item.open .faq-answer { display: block; }

/* === Table === */
.table-wrap { overflow-x: auto; margin: 1.5rem 0; }
table { width: 100%; border-collapse: collapse; font-size: 0.95rem; }
thead { background: rgba(245,158,11,0.1); }
th { padding: 0.9rem 1rem; text-align: left; font-weight: 700; color: var(--primary); border-bottom: 2px solid var(--primary); }
td { padding: 0.75rem 1rem; border-bottom: 1px solid var(--border); color: var(--text-muted); }
tr:hover td { background: rgba(245,158,11,0.03); }
td:first-child { font-weight: 600; color: var(--text); }

/* === Trust Bar === */
.trust-bar { display: flex; justify-content: center; gap: 2rem; flex-wrap: wrap; padding: 1.5rem; background: var(--card); border-radius: var(--radius); border: 1px solid var(--border); }
.trust-item { display: flex; align-items: center; gap: 0.5rem; color: var(--success); font-size: 0.95rem; font-weight: 600; }
.trust-item .check { font-size: 1.2rem; }

/* === Breadcrumbs === */
.breadcrumbs { padding: 1rem 0; font-size: 0.85rem; color: var(--text-dim); }
.breadcrumbs a { color: var(--text-muted); }
.breadcrumbs a:hover { color: var(--primary); }
.breadcrumbs span { color: var(--text-dim); }
.breadcrumbs .sep { margin: 0 0.5rem; color: var(--border); }

/* === Content Area === */
.content { max-width: 820px; margin: 0 auto; padding: 2rem 0; }
.content-meta { display: flex; gap: 1.5rem; font-size: 0.85rem; color: var(--text-dim); margin: 1rem 0 2rem; flex-wrap: wrap; }
.content-meta span { display: flex; align-items: center; gap: 0.3rem; }
.feature-image { width: 100%; border-radius: var(--radius); margin: 1.5rem 0; }
.tip-box {
  background: rgba(245,158,11,0.08);
  border: 1px solid rgba(245,158,11,0.2);
  border-radius: var(--radius-sm);
  padding: 1.25rem;
  margin: 1.5rem 0;
}
.tip-box h4 { color: var(--primary); margin-top: 0; }

/* === Legal Pages === */
.legal-content { max-width: 800px; margin: 0 auto; padding: 2rem 0; }
.legal-content h2 { font-size: 1.3rem; }
.legal-content p, .legal-content li { font-size: 0.95rem; }

/* === Footer === */
.site-footer {
  background: var(--card);
  border-top: 1px solid var(--border);
  padding: 3rem 0 2rem;
  margin-top: 3rem;
}
.footer-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); gap: 2rem; }
.footer-col h4 { color: var(--text); margin-bottom: 1rem; }
.footer-col ul { list-style: none; margin: 0; }
.footer-col ul li { margin-bottom: 0.5rem; }
.footer-col ul a { color: var(--text-muted); font-size: 0.9rem; }
.footer-col ul a:hover { color: var(--primary); }
.footer-bottom { text-align: center; padding-top: 2rem; margin-top: 2rem; border-top: 1px solid var(--border); color: var(--text-dim); font-size: 0.85rem; }

/* === CTA Section === */
.cta-section { text-align: center; padding: 3rem 0; }
.cta-section h2 { padding-bottom: 0; }
.cta-section h2::after { left: 50%; transform: translateX(-50%); }

/* === Highlight === */
.highlight { color: var(--primary); }
.badge { display: inline-block; background: rgba(245,158,11,0.15); color: var(--primary); padding: 0.15rem 0.6rem; border-radius: 4px; font-size: 0.8rem; font-weight: 600; }
.price-tag { font-size: 2rem; font-weight: 800; color: var(--success); }
.strikethrough { text-decoration: line-through; color: var(--text-dim); }

/* === Responsive === */
@media (max-width: 768px) {
  h1 { font-size: 1.8rem; }
  h2 { font-size: 1.4rem; }
  .hero h1 { font-size: 2rem; }
  .hero p { font-size: 1rem; }
  .nav-links { display: none; }
  .nav-links.open { display: flex; flex-direction: column; position: absolute; top: 64px; left: 0; right: 0; background: var(--bg); padding: 1.5rem; border-bottom: 1px solid var(--border); }
  .mobile-toggle { display: block; }
  .trust-bar { gap: 1rem; flex-direction: column; align-items: center; }
  .cards-grid, .download-cards { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 480px) {
  .container { padding: 0 1rem; }
  .footer-grid { grid-template-columns: 1fr; }
}