*{
  box-sizing:border-box;
}

body{
  margin:0;
  font-family:Arial, sans-serif;
  background:#f7f7fb;
  color:#101828;
}

.site-header{
  display:flex;
  justify-content:space-between;
  align-items:center;
  padding:15px 18px;
  background:#2b2d42;
  color:#fff;
  position:relative;
}

.logo{
  margin:0;
  font-size:20px;
}

.nav{
  display:flex;
  gap:20px;
}

nav a {
  color: white;
  text-decoration: none;
  margin-left: 20px;
  padding: 8px 14px;
  border-radius: 6px;
  transition: 0.3s;
}

nav > a:hover {
  background: #00c853;
}

.burger{
  display:none;
  font-size:26px;
  background:none;
  border:none;
  color:#fff;
  cursor:pointer;
}

.wrap{
  max-width:1100px;
  margin:auto;
  padding:30px 20px 50px;
}

.hero{
  text-align:center;
  margin-bottom:28px;
}

.eyebrow{
  margin:0 0 10px;
  color:#7c3aed;
  font-size:13px;
  font-weight:700;
  text-transform:uppercase;
  letter-spacing:1px;
}

.hero h1{
  margin:0 0 12px;
  font-size:40px;
}

.hero-text{
  max-width:680px;
  margin:0 auto;
  color:#667085;
  line-height:1.7;
}

.calculator-card{
  display:grid;
  grid-template-columns:1fr 1fr;
  gap:24px;
  background:white;
  border-radius:24px;
  padding:26px;
  box-shadow:0 12px 30px rgba(0,0,0,0.07);
  margin-bottom:24px;
}

.card-left h2{
  margin:0 0 6px;
}

.card-subtitle{
  margin:0 0 20px;
  color:#667085;
}

.grid{
  display:grid;
  grid-template-columns:repeat(2, 1fr);
  gap:16px;
}

.full{
  grid-column:1 / -1;
}

.field{
  margin-bottom:18px;
}

.field label{
  display:block;
  margin-bottom:8px;
  font-weight:600;
}

.field input,
.field select{
  width:100%;
  padding:13px;
  border:1px solid #d0d5dd;
  border-radius:14px;
  font-size:15px;
  background:#fff;
}

.section-block{
  margin-top:10px;
}

.section-top{
  display:flex;
  justify-content:space-between;
  align-items:center;
  gap:12px;
  margin-bottom:12px;
  flex-wrap:wrap;
}

.section-top h3{
  margin:0;
  font-size:18px;
}

.switch-group{
  display:flex;
  gap:8px;
}

.switch-btn{
  padding:10px 14px;
  border:1px solid #d0d5dd;
  background:#fff;
  border-radius:12px;
  cursor:pointer;
  font-weight:700;
}

.switch-btn.active{
  background:#f3e8ff;
  border-color:#c4b5fd;
  color:#6d28d9;
}

.calculate-btn{
  width:100%;
  margin-top:8px;
  border:none;
  border-radius:16px;
  background:#7c3aed;
  color:white;
  padding:15px;
  font-size:16px;
  font-weight:700;
  cursor:pointer;
}

.calculate-btn:hover{
  background:#6d28d9;
}

.card-right{
  background:linear-gradient(180deg, #faf5ff, #ffffff);
  border:1px solid #ede9fe;
  border-radius:22px;
  padding:24px;
  display:flex;
  flex-direction:column;
  justify-content:center;
}

.result-main{
  text-align:center;
  margin-bottom:20px;
}

.result-label{
  display:block;
  color:#6b21a8;
  margin-bottom:8px;
  font-weight:600;
}

.result-main strong{
  display:block;
  font-size:42px;
  color:#7c3aed;
  line-height:1.1;
}

.result-unit{
  display:block;
  margin-top:4px;
  color:#7c3aed;
}

.result-stats{
  display:grid;
  grid-template-columns:1fr;
  gap:12px;
}

.stat-box{
  background:white;
  border:1px solid #ede9fe;
  border-radius:16px;
  padding:16px;
  text-align:center;
}

.stat-box span{
  display:block;
  color:#667085;
  font-size:14px;
  margin-bottom:8px;
}

.stat-box strong{
  font-size:22px;
  color:#111827;
}

.result-note{
  margin:18px 0 0;
  color:#475467;
  line-height:1.6;
  text-align:center;
}

.info-grid{
  display:grid;
  grid-template-columns:1fr 1fr;
  gap:24px;
}

.info-card{
  background:white;
  border-radius:22px;
  padding:24px;
  box-shadow:0 12px 30px rgba(0,0,0,0.07);
}

.info-card h2{
  margin-top:0;
}

.info-card p{
  color:#475467;
  line-height:1.7;
}

.faq-item{
  margin-bottom:18px;
}

.faq-item:last-child{
  margin-bottom:0;
}

.faq-item h3{
  margin-bottom:8px;
}

.hidden{
  display:none;
}

@media (max-width:900px){
  .calculator-card{
    grid-template-columns:1fr;
  }

  .info-grid{
    grid-template-columns:1fr;
  }
}

@media (max-width:700px){
  .grid{
    grid-template-columns:1fr;
  }

  .hero h1{
    font-size:32px;
  }
}

@media (max-width:600px){
  .burger{
    display:block;
  }

  .nav{
    display:none;
    position:absolute;
    top:60px;
    left:0;
    right:0;
    background:#2b2d42;
    flex-direction:column;
    padding:15px;
    z-index:1000;
  }

  .nav.open{
    display:flex;
  }
}