:root{
  --primary:#1f8fb3;
  --dark:#0f4f65;
  --bg:#f5fbff;
  --card:#ffffff;
  --accent:#7ec8df;
  --max-width:1100px;
}
*{box-sizing:border-box}
body{font-family:Inter, Arial, sans-serif;background:var(--bg);margin:0;color:#102a43;}
.container{max-width:var(--max-width);margin:0 auto;padding:1rem;}
.header{background:linear-gradient(180deg,var(--primary),var(--dark));color:white;padding:1.2rem 0;text-align:center;position:relative;}
.logo-img{display:block;margin:0 auto;width:96px;height:96px;object-fit:contain;border-radius:12px;background:transparent;}
.site-title{font-size:1.6rem;margin:0.4rem 0 0;font-weight:700;letter-spacing:0.6px;}
.nav{background:transparent;display:flex;justify-content:center;padding:0.6rem 0;}
.tabs{display:flex;gap:0.3rem;flex-wrap:wrap;justify-content:center;}
.tab-btn{background:rgba(255,255,255,0.12);border:none;color:white;padding:0.55rem 0.9rem;border-radius:8px;cursor:pointer;font-weight:600;}
.tab-btn.active{background:white;color:var(--dark);box-shadow:0 6px 18px rgba(15,79,101,0.12);}
.main{padding:1.2rem;}
.card{background:var(--card);border-radius:12px;padding:1rem;margin:1rem 0;box-shadow:0 6px 16px rgba(16,42,67,0.06);}
.calc-grid{display:grid;grid-template-columns:1fr 360px;gap:1rem;}
@media(max-width:900px){.calc-grid{grid-template-columns:1fr;} .nav{padding:0} .tab-btn{padding:0.6rem 0.8rem}}
.form-row{display:flex;gap:0.6rem;margin-bottom:0.8rem;flex-wrap:wrap;}
.form-row label{flex:1;min-width:140px;display:flex;flex-direction:column;font-size:0.9rem;color:#334e68;}
input[type=number], input[type=text], select{padding:0.6rem;border-radius:8px;border:1px solid #e6eef4;background:#fbfdff;font-size:0.95rem;}
.small{max-width:140px;}
.result-box{background:linear-gradient(180deg,var(--accent),#eaf7fb);padding:0.8rem;border-radius:8px;font-weight:700;}
.ad-placeholder{min-height:90px;border-radius:8px;border:2px dashed #cfeff9;display:flex;align-items:center;justify-content:center;color:#6aaec6;font-weight:600;}
.ad-placeholder.hidden{display:none;}
.footer{padding:1rem;text-align:center;color:#5c6b73;font-size:0.9rem;}
.hint{font-size:0.85rem;color:#6b7a82;}

/* Result box style - blue background with white text */
.result-box-blue{background:linear-gradient(180deg,var(--accent),#0b7db8);color:#fff;padding:0.8rem;border-radius:8px;font-weight:700;text-align:center;}
.calc-actions{margin-top:0.8rem;display:flex;flex-direction:column;gap:0.6rem;}