/* DNA SPACE — main.css v5.0 */
body{background:#f8fafc;color:#D1D5DB;font-family:-apple-system,BlinkMacSystemFont,'PingFang SC','Microsoft YaHei',sans-serif;margin:0;overflow-x:hidden}
.site-header{position:sticky;top:0;z-index:100;background:rgba(2,8,18,.94);backdrop-filter:blur(18px);border-bottom:1px solid rgba(37,99,235,.1)}
.header-inner{max-width:1200px;margin:0 auto;padding:0 24px;display:flex;align-items:center;height:60px;gap:24px}
.logo{display:flex;align-items:center;gap:8px;font-size:1.15rem;font-weight:700;color:#F3F4F6;text-decoration:none}
.main-nav{display:flex;gap:2px;flex:1}
.nav-link,.nav-dropdown>a{padding:8px 10px;font-size:.83rem;color:#6B7280;text-decoration:none;border-radius:8px;transition:all .15s;white-space:nowrap}
.nav-link:hover,.nav-dropdown>a:hover{color:#F3F4F6;background:rgba(37,99,235,.08)}
.nav-dropdown{position:relative}
.dropdown-menu{position:absolute;top:100%;left:50%;transform:translateX(-50%);min-width:160px;padding:8px 0;background:rgba(7,20,40,.97);border:1px solid rgba(37,99,235,.1);border-radius:12px;opacity:0;visibility:hidden;transition:all .22s;box-shadow:0 12px 36px rgba(0,0,0,.5);z-index:200}
.nav-dropdown:hover .dropdown-menu{opacity:1;visibility:visible}
.dropdown-item{display:block;padding:9px 18px;font-size:.84rem;color:#6B7280;text-decoration:none;transition:all .15s}
.dropdown-item:hover{background:rgba(37,99,235,.08);color:#F3F4F6}
.btn-login,.btn-register{padding:7px 14px;font-size:.85rem;border-radius:50px;text-decoration:none}
.btn-login{color:#2563eb;border:1px solid rgba(37,99,235,.3)}
.btn-register{background:#2563eb;color:#fff}
.btn-login:hover{background:rgba(37,99,235,.08)}
.mobile-toggle{display:none;background:none;border:none;color:#6B7280;font-size:1.5rem;cursor:pointer}
.hero{padding:80px 24px 60px;text-align:center;position:relative}
.hero-title{font-size:3.5rem;font-weight:700;color:#F3F4F6;margin:0}
.hero-subtitle{font-size:1.2rem;color:#2563eb;margin:12px 0}
.hero-desc{font-size:.95rem;color:#6B7280;margin:8px 0 28px}
.hero-actions{display:flex;gap:14px;justify-content:center}
.btn-primary,.btn-ghost{padding:12px 28px;border-radius:8px;font-size:.95rem;font-weight:600;text-decoration:none;transition:all .2s}
.btn-primary{background:#2563eb;color:#fff}
.btn-ghost{color:#2563eb;border:2px solid rgba(37,99,235,.3)}
.btn-primary:hover{box-shadow:0 0 24px rgba(37,99,235,.25)}
.hero-stats{display:flex;justify-content:center;gap:60px;margin-top:40px}
.stat-num{display:block;font-size:2rem;font-weight:700;color:#2563eb}
.stat-label{font-size:.78rem;color:#6B7280}
.section{padding:60px 24px;position:relative;z-index:1}
.section-alt{background:rgba(37,99,235,.02)}
.section-header{max-width:1100px;margin:0 auto 24px;display:flex;align-items:baseline;justify-content:space-between}
.section-title{font-size:1.4rem;font-weight:600;color:#F3F4F6;margin:0}
.section-desc{font-size:.88rem;color:#6B7280}
.section-more{font-size:.85rem;color:#2563eb;text-decoration:none}
.tools-tabs{display:flex;justify-content:center;gap:0;margin-bottom:24px}
.tools-tab{padding:10px 28px;font-size:.92rem;cursor:pointer;border:1px solid rgba(48,54,61,.5);background:rgba(13,17,27,.6);color:#8b949e;transition:all .2s}
.tools-tab:first-child{border-radius:8px 0 0 8px}
.tools-tab:last-child{border-radius:0 8px 8px 0}
.tools-tab.active{background:rgba(0,240,255,.12);border-color:rgba(0,240,255,.4);color:#00f0ff;font-weight:600}
.tools-panel{display:none}
.tools-panel.active{display:block}
.tools-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:20px;max-width:1100px;margin:0 auto}
.tool-card{display:flex;flex-direction:column;padding:28px 22px;background:rgba(7,20,40,.78);border:1px solid rgba(37,99,235,.1);border-radius:16px;text-decoration:none;color:#D1D5DB;transition:all .2s;min-height:150px;backdrop-filter:blur(14px)}
.tool-card:hover{transform:translateY(-2px);border-color:rgba(37,99,235,.3)}
.tool-card-icon{font-size:2.2rem;margin-bottom:14px}
.tool-card-name{font-size:1rem;font-weight:600;color:#F3F4F6;margin:0}
.card-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:20px;max-width:1100px;margin:0 auto}
.research-card,.tutorial-card{background:rgba(7,20,40,.78);border:1px solid rgba(37,99,235,.1);border-radius:16px;padding:20px;text-decoration:none;color:#D1D5DB;transition:all .2s;display:block;backdrop-filter:blur(14px)}
.research-card:hover,.tutorial-card:hover{transform:translateY(-2px);border-color:rgba(37,99,235,.3)}
.research-title,.tutorial-title{font-size:.95rem;font-weight:600;color:#F3F4F6;margin:0 0 8px;line-height:1.4}
.research-desc,.tutorial-desc{font-size:.82rem;color:#6B7280;line-height:1.5;margin:0 0 10px}
.research-meta,.tutorial-meta{display:flex;justify-content:space-between;font-size:.75rem;color:#4B5563}
.site-footer{background:rgba(2,8,18,.95);border-top:1px solid rgba(37,99,235,.1);padding:48px 24px 24px;position:relative;z-index:1}
.footer-inner{max-width:1100px;margin:0 auto}
.footer-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:36px}
.footer-col h4{color:#F3F4F6;font-size:.95rem;margin:0 0 14px}
.footer-col a{display:block;color:#6B7280;font-size:.85rem;line-height:2;text-decoration:none}
.footer-col a:hover{color:#2563eb}
.footer-bottom{text-align:center;padding-top:28px;margin-top:28px;border-top:1px solid rgba(37,99,235,.1);color:#4B5563;font-size:.78rem}
@media(max-width:767px){.tools-grid,.card-grid{grid-template-columns:1fr}.hero-title{font-size:2rem}.hero-stats{gap:30px;flex-wrap:wrap}.footer-grid{grid-template-columns:repeat(2,1fr)}.main-nav{display:none}}

/* ─── 响应式断点补充 (2026-08-04 SEO移动落地页合规) ─── */
@media(max-width:1024px){
  .footer-grid{grid-template-columns:repeat(2,1fr);gap:24px}
  .tools-grid,.card-grid{grid-template-columns:repeat(2,1fr)}
  .hero-title{font-size:2.6rem}
  .section{padding:40px 20px}
}
@media(max-width:768px){
  .tools-grid,.card-grid{grid-template-columns:1fr}
  .hero{padding:48px 16px 32px}
  .hero-title{font-size:2rem}
  .hero-desc{font-size:.9rem;line-height:1.7}
  .tools-tabs{flex-wrap:wrap}
  .tools-tab{padding:8px 16px;font-size:.85rem;flex:1;min-width:0;text-align:center}
  .section-header{flex-direction:column;align-items:flex-start;gap:8px}
  .features-grid{grid-template-columns:repeat(2,1fr)}
}
@media(max-width:480px){
  .hero-title{font-size:1.6rem}
  .hero-subtitle{font-size:.95rem}
  .features-grid{grid-template-columns:1fr}
  .footer-grid{grid-template-columns:1fr;gap:20px}
  .btn-primary,.btn-ghost{padding:10px 20px;font-size:.88rem}
  .tool-card{padding:20px 16px}
  .section{padding:32px 14px}
}

/* ─── Glitch gradient hero title (2026-08-04: 恢复渐变色文字, 页面用 glitch-text 类但全站 CSS 无定义) ─── */
.glitch-text{
  background:linear-gradient(135deg,#2563eb 0%,#8B5CF6 30%,#EC4899 60%,#2563eb 100%);
  background-size:300% 300%;
  -webkit-background-clip:text;background-clip:text;
  color:transparent;display:inline-block;text-shadow:none;
  animation:dnaGradFlow 5s ease infinite;
}
@keyframes dnaGradFlow{
  0%{background-position:0% 50%}
  50%{background-position:100% 50%}
  100%{background-position:0% 50%}
}