:root{--accent:#00eaff;--bg:#0c0c0f;--bg-glass:rgba(24,24,28,.6);--text:#e3e3e7;}
body.light{--bg:#fff;--bg-glass:rgba(255,255,255,.6);--text:#121212;}
*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
body{font-family:'Inter',sans-serif;background:var(--bg);color:var(--text);line-height:1.6;scroll-behavior:smooth;
background-image:radial-gradient(circle at 20% 20%,rgba(0,234,255,.15),transparent 40%),radial-gradient(circle at 80% 0%,rgba(255,0,128,.08),transparent 50%),radial-gradient(circle at 50% 80%,rgba(0,255,170,.1),transparent 50%);transition:background .6s,color .6s;}
a{color:var(--accent);text-decoration:none}
.site-header{display:flex;justify-content:space-between;align-items:center;padding:1rem 2rem;position:fixed;top:0;width:100%;z-index:100;
background:var(--bg-glass);backdrop-filter:blur(18px) brightness(1.05);border-bottom:1px solid rgba(255,255,255,.08);}
.logo{font-family:'Space Grotesk',sans-serif;font-size:1.8rem}
nav ul{display:flex;gap:1.2rem;list-style:none;align-items:center}
.hero{display:flex;align-items:center;justify-content:center;min-height:100vh;text-align:center;padding:0 1rem;}
.glass{background:var(--bg-glass);border:1px solid rgba(255,255,255,.12);backdrop-filter:blur(18px) brightness(1.05);border-radius:24px;
box-shadow:inset 0 1px 2px rgba(255,255,255,.08),0 4px 18px rgba(0,0,0,.45);}
.hero-content{max-width:720px;padding:3rem}
.btn{display:inline-block;margin-top:1.2rem;background:var(--accent);color:#000;font-weight:600;padding:.8rem 1.4rem;border:none;
border-radius:24px;box-shadow:0 4px 12px rgba(0,234,255,.35);transition:transform .2s cubic-bezier(.25,.8,.35,1);}
.btn:hover{transform:translateY(-3px)}
.section{max-width:1100px;margin:4rem auto;padding:0 1rem}
.section h3{font-family:'Space Grotesk',sans-serif;font-size:2rem;margin-bottom:1rem;color:var(--accent)}
.cards{display:grid;grid-template-columns:repeat(auto-fit,minmax(260px,1fr));gap:2rem;margin-top:1rem}
.card{background:rgba(0,0,0,.3);padding:1.5rem;border-radius:20px;box-shadow:inset 0 1px 2px rgba(255,255,255,.05),0 2px 8px rgba(0,0,0,.5)}
footer{text-align:center;padding:2rem 1rem;color:rgba(255,255,255,.6)}
.social{margin-top:.5rem;display:flex;gap:1rem;justify-content:center}
#mode-toggle{background:none;border:none;font-size:1.25rem;color:var(--text);cursor:pointer}