:root{
    --green:#5c7f78;         /* header/footer */
    --green-dark:#4f6f69;    /* button hover */
    --text:#111;
    --muted:#5b5b5b;
    --bg:#ffffff;
    --line:#dcdcdc;
  }
  
  *{box-sizing:border-box}
  
  body{
    margin:0;
    font-family: system-ui, -apple-system, Segoe UI, Roboto, Helvetica, Arial, sans-serif;
    color:var(--text);
    background:var(--bg);
  }
  
  /* Top bar */
  header{
    background:var(--green);
    color:#fff;
    height:64px;
    display:flex;
    align-items:center;
  }
  
  .header-inner{
    width:min(1120px, 92vw);
    margin:0 auto;
    display:flex;
    align-items:center;
    justify-content:space-between;
  }
  
  .brand{
    font-weight:800;
    font-size:34px;
    letter-spacing:.2px;
    line-height:1;
    display:flex;
    align-items:baseline;
    gap:6px;
  }
  .brand small{
    font-weight:700;
    font-size:14px;
    opacity:.95;
    transform: translateY(6px);
  }
  
  nav a{
    color:#fff;
    text-decoration:none;
    font-size:14px;
    margin-left:28px;
    opacity:.95;
  }
  nav a:hover{opacity:1;text-decoration:underline}
  .nav-link.active{
    text-decoration:underline;
    opacity:1;
  }
  
  /* Main */
  main{
    width:min(980px, 92vw);
    margin:52px auto 0;
    text-align:center;
  }
  
  .page{
    min-height: 420px;
  }
  
  h1{
    margin:0 0 10px 0;
    font-size:30px;
    font-weight:800;
  }
  
  .subtitle{
    margin:0 auto 34px;
    color:var(--muted);
    font-size:14px;
    line-height:1.5;
    max-width:720px;
  }
  
  /* Calculator */
  .calc-row{
    margin:0 auto;
    display:flex;
    align-items:center;
    justify-content:center;
    gap:12px;
    flex-wrap:wrap;
  }
  
  .calc-row label{
    font-weight:700;
    font-size:14px;
  }
  
  .calc-row input{
    width:190px;
    height:36px;
    border:1px solid var(--line);
    border-radius:2px;
    padding:0 10px;
    font-size:14px;
    outline:none;
  }
  
  .calc-row input:focus{
    border-color:#b8b8b8;
    box-shadow:0 0 0 3px rgba(92,127,120,.15);
  }
  
  .btn{
    margin:18px auto 0;
    width:min(520px, 92vw);
    height:44px;
    background:var(--green);
    color:#fff;
    border:none;
    border-radius:4px;
    font-weight:700;
    cursor:pointer;
    display:block;
  }
  
  .btn:hover{background:var(--green-dark)}
  
  .btn.btn-small{
    width: min(260px, 92vw);
  }
  
  .result{
    margin:16px auto 0;
    max-width:740px;
    text-align:center;
    font-size:14px;
    line-height:1.55;
    color:#1f1f1f;
    min-height:24px;
  }
  
  .result strong{font-weight:800}
  .result .bad{color:#8a1f1f}
  .result .ok{color:#1a5e2a}
  
  /* FAQ */
  .faq{
    width:min(860px, 92vw);
    margin:64px auto 0;
    text-align:left;
  }
  
  .faq-item{
    display:grid;
    grid-template-columns:40px 1fr;
    column-gap:22px;
    align-items:start;
    margin:28px 0 44px;
  }
  
  .square{
    width:22px;
    height:22px;
    border:3px solid #91b1a9;
    border-radius:2px;
    margin-top:6px;
  }
  
  .faq h2{
    margin:0 0 8px 0;
    font-size:18px;
    font-weight:900;
  }
  
  .faq p{
    margin:0;
    color:#3a3a3a;
    font-size:14px;
    line-height:1.6;
    max-width:720px;
  }
  
  /* Contact page */
  .contact-card{
    width:min(720px, 92vw);
    margin:0 auto;
    text-align:left;
  }
  
  .contact-form{
    border:1px solid var(--line);
    border-radius:6px;
    padding:18px;
  }
  
  .contact-form label{
    display:block;
    font-size:13px;
    font-weight:700;
    color:#2b2b2b;
    margin:12px 0 6px;
  }
  
  .contact-form input,
  .contact-form textarea{
    width:100%;
    border:1px solid var(--line);
    border-radius:4px;
    padding:10px 10px;
    font-size:14px;
    outline:none;
  }
  
  .contact-form input:focus,
  .contact-form textarea:focus{
    border-color:#b8b8b8;
    box-shadow:0 0 0 3px rgba(92,127,120,.15);
  }
  
  .contact-note{
    margin:10px 0 0;
    color:var(--muted);
    font-size:12px;
  }
  
  /* Footer */
  footer{
    margin-top:56px;
    background:var(--green);
    color:#fff;
    text-align:center;
    padding:26px 14px 18px;
  }
  
  footer .fun{
    font-size:14px;
    opacity:.95;
    margin:0 0 14px;
  }
  
  footer .copy{
    font-size:12px;
    opacity:.9;
    margin:0;
  }
  
  /* Small screens */
  @media (max-width:520px){
    .brand{font-size:28px}
    .brand small{transform: translateY(5px)}
    nav a{margin-left:16px}
  }