.area-wrap{max-width:580px;margin:0 auto;font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,sans-serif;color:#1a1a1a}
.area-header{display:flex;align-items:center;gap:12px;margin-bottom:20px}
.area-icon{font-size:34px;line-height:1}
.area-title{font-size:22px!important;font-weight:600!important;margin:0 0 3px!important;padding:0!important;border:none!important;color:#1a1a1a!important}
.area-sub{font-size:13px;color:#666;margin:0}
.area-shape-select{display:flex;gap:7px;margin-bottom:18px;flex-wrap:wrap}
.area-shape-btn{padding:9px 14px;font-size:13px;font-weight:500;border:1px solid #d0d0d0;border-radius:9px;background:#fff;color:#555;cursor:pointer;transition:background .13s}
.area-shape-btn:hover:not(.act){background:#eff6ff}
.area-shape-btn.act{background:#dbeafe;color:#1D4ED8;border-color:#93c5fd;font-weight:700}
.area-grid2{display:grid;grid-template-columns:1fr 1fr;gap:12px}
.area-grid3{display:grid;grid-template-columns:1fr 1fr 1fr;gap:12px}
@media(max-width:420px){.area-grid2,.area-grid3{grid-template-columns:1fr}}
.area-lbl{display:block;font-size:13px;font-weight:500;color:#555;margin-bottom:5px}
.area-iw input{width:100%;box-sizing:border-box;padding:9px 12px;border:1px solid #d0d0d0;border-radius:8px;font-size:14px;color:#1a1a1a;background:#fff;outline:none;-moz-appearance:textfield}
.area-iw input::-webkit-inner-spin-button,.area-iw input::-webkit-outer-spin-button{-webkit-appearance:none}
.area-iw input:focus{border-color:#1D4ED8;box-shadow:0 0 0 3px rgba(29,78,216,.1)}
.area-group{margin-bottom:10px}
.area-result-card{background:linear-gradient(135deg,#1D4ED8,#1e3a8a);border-radius:12px;padding:18px 22px;color:#fff;margin-top:12px;text-align:center;animation:area-in .22s ease}
@keyframes area-in{from{opacity:0;transform:translateY(5px)}to{opacity:1;transform:translateY(0)}}
.area-res-main{font-size:38px;font-weight:800;font-family:monospace;margin-bottom:4px}
.area-res-sub{font-size:14px;opacity:.8}
.area-formula-box{background:#fafafa;border:1px solid #e8e8e8;border-radius:10px;padding:12px 16px;margin-top:10px;text-align:center;font-size:13px;color:#555}
.area-formula-box strong{color:#1D4ED8;font-family:monospace}