:root{
  --bg: #f7f8fb;
  --card: #ffffff;
  --text: #0f1724;
  --muted: #6b7280;
  --accent: #5b8def;
  --accent-contrast: #ffffff;
  --glass: rgba(255,255,255,0.6);

  --radius: 12px;
}

[data-theme="dark"]{
  --bg: #0b0f14;
  --card: #081019;
  --text: #e6eef8;
  --muted: #9aa6b2;
  --accent: #5b8def;
  --accent-contrast: #081019;
  --glass: rgba(255,255,255,0.03);
}

*{box-sizing:border-box}
html,body{height:100%}
body{
  margin:0;
  font-family: 'Inter', system-ui, -apple-system, 'Segoe UI', Roboto, 'Helvetica Neue', Arial;
  background:var(--bg);
  color:var(--text);
  -webkit-font-smoothing:antialiased;
  -moz-osx-font-smoothing:grayscale;
  line-height:1.5;
}

.container{max-width:1100px;margin:0 auto;padding:1rem}

.skip-link{position:absolute;left:-999px;top:auto;width:1px;height:1px;overflow:hidden}
.skip-link:focus{left:1rem;top:1rem;width:auto;height:auto;background:var(--card);padding:.5rem;border-radius:6px}

.header-grid{display:flex;align-items:center;gap:1rem;justify-content:space-between;padding:1rem 0}
.brand{display:flex;align-items:center;gap:.6rem;color:var(--text);text-decoration:none}
.brand .logo{color:var(--text)}
.brand-name{font-weight:700}

.nav-list{display:flex;gap:0.5rem;list-style:none;margin:0;padding:0}
.nav-link{padding:.4rem .6rem;border-radius:8px;text-decoration:none;color:var(--muted)}
.nav-link:hover{color:var(--text);background:var(--glass);transform:translateY(-1px);transition:transform .12s ease}
.nav-link.active{color:var(--accent);font-weight:600}

.nav-toggle{display:none;border:0;background:transparent}
.hamburger{width:28px;height:2px;background:var(--text);display:block;position:relative}
.hamburger::before,.hamburger::after{content:"";position:absolute;left:0;width:28px;height:2px;background:var(--text)}
.hamburger::before{top:-8px}
.hamburger::after{top:8px}

.header-actions{display:flex;align-items:center;gap:.5rem}
.btn{border:0;padding:.6rem .9rem;border-radius:10px;background:transparent;cursor:pointer}
.btn.primary{background:var(--accent);color:var(--accent-contrast);font-weight:600}
.btn.ghost{background:transparent;border:1px solid rgba(0,0,0,0.06)}
.btn.outline{border:1px solid rgba(0,0,0,0.06)}

.hero{padding:2.5rem 0}
.hero-grid{display:grid;grid-template-columns:1fr 360px;gap:2rem;align-items:center}
.hero .lead{color:var(--muted)}

.device-mock{transform:translateY(0);transition:transform .5s ease,opacity .4s ease}

.tool{padding:1.5rem 0}
.card{background:var(--card);border-radius:var(--radius);padding:1rem;box-shadow:0 6px 18px rgba(13,14,18,0.04);margin-top:1rem}
.tool-card{display:grid;gap:1rem}
.form-row{display:block;margin-bottom:.75rem}
.input-group{display:flex;gap:.5rem;align-items:center}
.input-group input[type="number"], input[type="email"], textarea{flex:1;padding:.6rem .75rem;border-radius:8px;border:1px solid rgba(0,0,0,0.06);background:transparent;color:var(--text)}
.input-group input[type="range"]{width:100%;margin-top:.5rem}
.presets{display:flex;gap:.4rem}
.preset{padding:.3rem .5rem;border-radius:6px;border:1px solid rgba(0,0,0,0.06);background:transparent;cursor:pointer}
.preset:hover{transform:translateY(-2px)}

.result-row{display:flex;align-items:center;justify-content:space-between;gap:1rem;margin-top:.5rem}
.result-value{font-size:1.5rem;font-weight:700}
.result-actions .btn{margin-left:.5rem}

.muted{color:var(--muted)}
.small{font-size:.9rem}

.faq{padding:1.5rem 0}
.accordion details{background:var(--card);padding:.75rem;border-radius:8px;margin-bottom:.5rem}
.accordion summary{cursor:pointer;outline:none}

.site-footer{margin-top:2.5rem;padding-top:1.5rem;border-top:1px solid rgba(0,0,0,0.04)}
.footer-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:1rem;padding:1rem 0}
.col-brand .socials{display:flex;gap:.5rem;margin-top:0.75rem}
.social{display:inline-flex;align-items:center;justify-content:center;padding:.4rem;border-radius:8px;background:var(--glass);transition:transform .18s ease}
.social:focus, .social:hover{transform:translateY(-4px);}
.footer-links{list-style:none;padding:0;margin:0}
.footer-links li{margin-bottom:.5rem}
.newsletter{display:flex;gap:.5rem}
.newsletter input{flex:1}
.footer-bottom{padding:1rem 0;border-top:1px solid rgba(0,0,0,0.03);margin-top:1rem}

/* Responsive */
@media (max-width: 900px){
  .hero-grid{grid-template-columns:1fr}
  .footer-grid{grid-template-columns:1fr 1fr}
}
@media (max-width: 600px){
  .nav-list{display:none}
  .nav-toggle{display:block}
  .footer-grid{grid-template-columns:1fr}
}

/* small utilities */
.visually-hidden{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap;border:0}

/* Subtle animations */
.card, .btn{transition:transform .16s ease, box-shadow .12s ease}

/* Focus styles */
:focus{outline:2px dashed var(--accent);outline-offset:3px}