:root{--blue:#003366;--accent:#0055aa;--white:#fff}
*{box-sizing:border-box}
body{font-family:Inter,system-ui,Arial,Helvetica,sans-serif;margin:0;background:#f7f9fb;color:#03223a}
.wrap{max-width:980px;margin:0 auto;padding:20px}
.top{background:var(--blue);color:var(--white);padding:30px 0}
.top h1{margin:0;font-size:28px}
.sub{opacity:.9;margin-top:6px}
.box{background:white;border:2px solid var(--blue);border-radius:10px;padding:18px;margin:18px 0}
.row{display:flex;gap:10px;align-items:center;margin:10px 0;flex-wrap:wrap}
label{min-width:80px;color:var(--blue);font-weight:600}
input{flex:1;padding:10px;border:1px solid #d6dbe3;border-radius:6px}
button.btn,button#calcBtn{background:var(--blue);color:var(--white);border:none;padding:10px 16px;border-radius:8px;cursor:pointer}
.result{margin-top:12px;padding:10px;background:#eef6ff;border-radius:6px;color:#03223a}
ul{padding-left:18px}
.bottom{padding:20px;text-align:center;color:#6b7b8a}
a{color:var(--accent);text-decoration:none}
a:hover{text-decoration:underline}