:root {
  --primary: #1b2a4a;
  --primary-light: #2d4a7a;
  --accent: #f47920;
  --accent-hover: #d9681a;
  --pass: #1e8449;
  --pass-bg: #eafaf1;
  --fail: #c0392b;
  --fail-bg: #fdedec;
  --warn: #d4920a;
  --bg: #eef0f4;
  --card: #ffffff;
  --text: #2c3e50;
  --muted: #7f8c8d;
  --border: #dce1e8;
  --input-bg: #f7f8fa;
  --radius: 10px;
}
*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth}
body{font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Oxygen,Ubuntu,Cantarell,sans-serif;background:var(--bg);color:var(--text);line-height:1.5;min-height:100vh}
.container{max-width:720px;margin:0 auto;padding:12px 12px 32px}
/* Header */
.header{background:#ffffff;color:var(--text);padding:20px 20px 16px;border-radius:var(--radius);margin-bottom:14px;text-align:center;position:relative;overflow:hidden;box-shadow:0 1px 4px rgba(0,0,0,0.06)}
.header-top{display:flex;flex-direction:column;align-items:center;gap:10px;margin-bottom:10px}
.header-logo{height:44px;width:auto}
.header-product{height:56px;width:auto;border-radius:6px}
.subtitle{font-size:11px;color:var(--muted);margin-top:4px;letter-spacing:0.5px}
/* Cards */
.card{background:var(--card);border-radius:var(--radius);padding:16px;margin-bottom:12px;box-shadow:0 1px 4px rgba(0,0,0,0.06)}
.card h2{font-size:13px;font-weight:700;text-transform:uppercase;letter-spacing:0.6px;color:var(--primary);margin-bottom:12px;padding-bottom:8px;border-bottom:2px solid var(--accent)}
/* Form */
.fg{margin-bottom:10px}
.fg label{display:block;font-size:12px;font-weight:600;color:var(--muted);margin-bottom:3px}
.fg label.chk{display:flex;align-items:center;gap:8px;font-size:13px;color:var(--text);cursor:pointer}
.fg label.chk input{width:18px;height:18px;accent-color:var(--accent)}
select,input[type="number"]{width:100%;padding:10px 12px;font-size:15px;border:1px solid var(--border);border-radius:7px;background:var(--input-bg);color:var(--text);transition:border-color .2s,box-shadow .2s}
select{-webkit-appearance:none;-moz-appearance:none;appearance:none;background-image:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' fill='%237f8c8d'%3E%3Cpath d='M2 4l4 4 4-4'/%3E%3C/svg%3E");background-repeat:no-repeat;background-position:right 12px center;background-size:12px;padding-right:36px}
select:focus,input[type="number"]:focus{outline:none;border-color:var(--accent);box-shadow:0 0 0 3px rgba(244,121,32,0.12)}
select:disabled{opacity:.45;cursor:not-allowed}
.fr{display:flex;gap:10px}
.fr .fg{flex:1;min-width:0}
.fg small{display:block;font-size:11px;color:var(--muted);margin-top:2px}
.fg small.warn{color:var(--warn)}
.fg small.err{color:var(--fail)}
/* Info box */
.info-box{background:#f0f4fa;border:1px solid #d4dce8;border-radius:7px;padding:10px 12px;font-size:12px;color:var(--primary);line-height:1.7;margin-top:8px}
.info-box strong.err{color:var(--fail)}
/* Button */
.btn-calc{display:block;width:100%;padding:15px;font-size:16px;font-weight:700;text-transform:uppercase;letter-spacing:1px;background:var(--accent);color:#fff;border:none;border-radius:var(--radius);cursor:pointer;margin-bottom:14px;transition:background .15s,transform .1s}
.btn-calc:hover{background:var(--accent-hover)}
.btn-calc:active{transform:scale(0.985)}
.btn-calc:disabled{opacity:.6;cursor:not-allowed;transform:none}
/* Results */
.r-banner{text-align:center;padding:18px 16px;border-radius:var(--radius);margin-bottom:12px;font-size:22px;font-weight:800;letter-spacing:0.5px}
.r-pass{background:var(--pass);color:#fff}
.r-fail{background:var(--fail);color:#fff}
.r-util{font-size:14px;font-weight:400;margin-top:4px;opacity:.9}
.r-summary p{font-size:13px;margin-bottom:4px}
.r-summary strong{color:var(--primary)}
.factors-grid{display:flex;flex-wrap:wrap;gap:8px}
.factors-grid span{display:inline-block;background:#f0f4fa;border-radius:6px;padding:6px 10px;font-size:13px;font-weight:600;color:var(--primary)}
/* Results table */
.rtbl-wrap{overflow-x:auto;-webkit-overflow-scrolling:touch;margin-top:8px}
.rtbl{width:100%;border-collapse:collapse;font-size:12px;white-space:nowrap}
.rtbl th{background:var(--primary);color:#fff;padding:8px 8px;text-align:left;font-weight:600;font-size:11px}
.rtbl td{padding:7px 8px;border-bottom:1px solid var(--border)}
.rtbl tbody tr:nth-child(even){background:#f9fafb}
.rtbl .ref{display:block;font-size:10px;color:var(--muted);font-weight:400}
.s-ok{color:var(--pass);font-weight:700}
.s-fail{color:var(--fail);font-weight:700}
.s-na{color:var(--muted);font-style:italic;font-weight:400}
.gov-line{margin-top:8px;font-size:13px;font-weight:600;color:var(--primary)}
/* Step detail rows */
.rtbl tbody tr:not(.steps-row){cursor:pointer}
.rtbl tbody tr:not(.steps-row):hover{background:#eef3fa}
.steps-row{display:none}
.steps-row.show{display:table-row}
.steps-row>td{padding:0 8px 8px;background:#f8f9fb;border-bottom:1px solid var(--border)}
.steps-block{font-family:"SF Mono",SFMono-Regular,Menlo,Monaco,Consolas,monospace;font-size:11px;color:var(--muted);line-height:1.8;padding:6px 8px}
.step-line{white-space:nowrap}
.step-line b{color:var(--text)}
.row-expand{font-size:9px;color:var(--muted);margin-left:4px;transition:transform .15s;display:inline-block}
.steps-row.show+tr .row-expand,.rtbl tr.expanded .row-expand{transform:rotate(90deg)}
/* Combined steps */
.comb-steps{margin-top:10px;border-top:1px solid var(--border);padding-top:8px}
/* Combined */
.comb-box{background:#f8f9fb;border-radius:8px;padding:14px;margin-top:8px}
.comb-row{display:flex;justify-content:space-between;padding:5px 0;font-size:14px}
.comb-row.total{border-top:2px solid var(--border);padding-top:10px;margin-top:6px;font-weight:700;font-size:15px}
/* Footer */
.footer{text-align:center;padding:16px 12px;font-size:11px;color:var(--muted);line-height:1.6}
.disclaimer{background:var(--card);border-radius:var(--radius);padding:14px 16px;margin-bottom:12px;box-shadow:0 1px 4px rgba(0,0,0,0.06);font-size:10px;color:var(--muted);line-height:1.7;text-align:justify}
/* Tooltips */
.tip{position:relative;display:inline-block;cursor:help;margin-left:4px;vertical-align:middle}
.tip .tip-icon{display:inline-flex;align-items:center;justify-content:center;width:16px;height:16px;border-radius:50%;background:var(--primary-light);color:#fff;font-size:10px;font-weight:700;line-height:1}
.tip .tip-text{visibility:hidden;opacity:0;position:absolute;z-index:100;bottom:calc(100% + 6px);left:50%;transform:translateX(-50%);min-width:200px;max-width:280px;padding:8px 10px;background:var(--primary);color:#fff;font-size:11px;line-height:1.5;border-radius:6px;box-shadow:0 4px 12px rgba(0,0,0,0.2);white-space:normal;font-weight:400;transition:opacity .15s,visibility .15s;pointer-events:none}
.tip .tip-text::after{content:'';position:absolute;top:100%;left:50%;transform:translateX(-50%);border:5px solid transparent;border-top-color:var(--primary)}
.tip:hover .tip-text,.tip:focus .tip-text{visibility:visible;opacity:1}
/* Warn box for validation */
.val-warn{background:#fef9e7;border:1px solid #f9e79f;border-radius:7px;padding:8px 12px;font-size:12px;color:#7d6608;margin-top:6px;display:none}
.val-warn.show{display:block}
/* Assumption notes in results */
.assumptions{background:#eef6ff;border:1px solid #b3d4f7;border-radius:7px;padding:8px 12px;font-size:12px;color:#1a5276;margin-top:8px}
.assumptions p{margin:2px 0}
/* Brick thumbnail */
.sub-row{display:flex;align-items:center;gap:10px}
.sub-row select{flex:1;min-width:0}
.brick-thumb{max-width:156px;height:auto;border-radius:6px;border:1px solid var(--border);flex-shrink:0;display:none}
.brick-thumb.show{display:block}
/* Error page */
.err-page{max-width:480px;margin:80px auto;text-align:center;padding:32px;background:#fff;border-radius:var(--radius);box-shadow:0 2px 8px rgba(0,0,0,0.08)}
.err-page h1{color:var(--fail);font-size:20px;margin-bottom:12px}
.err-page p{color:var(--muted);font-size:14px}
/* Responsive */
@media(max-width:480px){
  .fr{flex-direction:column;gap:0}
  .container{padding:8px 8px 24px}
  .header{padding:16px 12px 12px}
  .header-logo{height:36px}
  .header-product{height:44px}
  .rtbl{font-size:11px}
  .rtbl th,.rtbl td{padding:6px 5px}
  .tip .tip-text{min-width:160px;max-width:220px;left:0;transform:none}
  .tip .tip-text::after{left:16px;transform:none}
}