:root{--content-width: 1180px;--bg: #f7f9fc;--surface: #ffffff;--surface-alt: #f2f5f8;--surface-blue: #f4f8ff;--text: #111827;--text-strong: #0b1220;--text-muted: #687386;--text-faint: #8c96a5;--border: #e2e7ed;--border-strong: #cfd7e1;--accent: #1672e8;--accent-hover: #0f61ca;--accent-soft: rgb(22 114 232 / 8%);--nav: #101827;--nav-muted: #aeb8c7;--success: #15803d;--warning: #c97800;--danger: #d14343;--radius-sm: 4px;--radius-md: 6px;--shadow-sm: none}body{margin:0;background:var(--bg);color:var(--text);font-family:Inter,ui-sans-serif,system-ui,-apple-system,BlinkMacSystemFont,Segoe UI,sans-serif;font-size:15px;line-height:1.55}h1,h2,h3{margin-top:0;line-height:1.15}h1{font-size:clamp(2rem,4vw,2.75rem);font-weight:750;letter-spacing:-.035em}h2{font-size:clamp(1.4rem,2.5vw,1.9rem);font-weight:700;letter-spacing:-.025em}h3{font-size:1rem;font-weight:700}a{color:var(--accent)}.container{width:min(var(--content-width),calc(100% - 2rem));margin-inline:auto}.section{padding:2.75rem 0}.section-alt{background:#f1f5f9;border-block:1px solid var(--border)}.eyebrow{margin:0 0 .45rem;color:var(--accent);font-size:.7rem;font-weight:750;letter-spacing:.09em;text-transform:uppercase}.site-header{background:var(--nav);border-bottom:1px solid rgb(255 255 255 / 8%)}.site-nav{min-height:64px;display:flex;align-items:center;justify-content:space-between;gap:1rem}.brand{display:flex;flex-direction:column;align-items:flex-start;line-height:1.2;text-decoration:none}.brand-name{color:#fff;font-size:1.1rem;font-weight:750;letter-spacing:-.02em}.brand-tag{color:var(--nav-muted);font-size:.72rem;letter-spacing:.04em}.main-menu{display:flex;flex-wrap:wrap;gap:.25rem}.main-menu a{padding:.45rem .6rem;border-radius:4px;color:#c9d2df;background:transparent;font-size:.86rem;font-weight:550;text-decoration:none}.main-menu a:hover{color:#fff;background:#ffffff0f}.main-menu a.is-current{color:#fff;background:#ffffff17}.panel{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius-md);box-shadow:none;padding:1.5rem}.panel-heading{margin:0 0 1rem;font-size:.69rem;font-weight:750;letter-spacing:.065em;text-transform:uppercase;color:var(--text-muted)}.calculator-grid{display:grid;grid-template-columns:.9fr 1.1fr;gap:0}.panel.calculator-grid{padding:0}.calculator-grid>.col{min-width:0;padding:1.5rem}.calculator-grid>.col+.col{border-left:1px solid var(--border)}.field{display:grid;gap:.35rem;margin-bottom:.85rem}.field>label{color:var(--text-strong);font-size:.8rem;font-weight:650}.field .hint{grid-column:1 / -1;color:var(--text-muted);font-size:.8rem}input,select,textarea{min-height:42px;border:1px solid var(--border-strong);border-radius:4px;background:#fff;color:var(--text);font:inherit;padding:.4rem .6rem}input[type=radio],input[type=checkbox]{min-height:auto;width:18px;height:18px;padding:0;accent-color:var(--accent)}textarea{min-height:120px;resize:vertical}input:hover,select:hover{border-color:#aeb9c7}input:focus-visible,select:focus-visible,textarea:focus-visible,.button-primary:focus-visible,.button-secondary:focus-visible{outline:2px solid rgb(22 114 232 / 18%);outline-offset:1px;border-color:var(--accent)}.input-unit{display:grid;grid-template-columns:1fr 84px;gap:.5rem}.radio-row{display:flex;flex-wrap:wrap;gap:.5rem 1.25rem;padding:.35rem 0}.radio-row label{display:flex;align-items:center;gap:.45rem;font-weight:500;cursor:pointer}.button-row{display:flex;flex-wrap:wrap;gap:.75rem;margin-top:1.25rem}.button-primary,.button-secondary{min-height:40px;padding:0 .95rem;border-radius:4px;font:inherit;font-size:.86rem;font-weight:650;cursor:pointer}.button-primary{border:1px solid var(--accent);background:var(--accent);color:#fff}.button-primary:hover{background:var(--accent-hover)}.button-secondary{background:#fff;border:1px solid var(--border-strong);color:var(--text)}.button-secondary:hover{border-color:#aeb9c7;color:var(--text-strong)}.diagram-wrap{background:linear-gradient(var(--surface-alt) 1px,transparent 1px),linear-gradient(90deg,var(--surface-alt) 1px,transparent 1px),#fbfcfe;background-size:24px 24px;border:1px solid var(--border);border-radius:4px;padding:1.5rem}.tank-diagram{display:block;width:100%;height:auto}.tank-outline{fill:#fff;stroke:#344054;stroke-width:2}.tank-liquid{fill:#1672e838;stroke:var(--accent);stroke-width:1}.dimension-line{stroke:#788597;stroke-width:1.25}.dimension-label{fill:#596579;font-size:13px;font-weight:650}.diagram-dim .is-active{stroke:var(--accent)}.diagram-dim text.is-active,.diagram-dim .is-active+text{fill:var(--accent)}.result-value-wrap{display:flex;align-items:baseline;gap:.5rem .75rem;flex-wrap:wrap}.result-value{color:var(--text-strong);font-size:clamp(2.4rem,5vw,3.4rem);font-weight:760;line-height:1;letter-spacing:-.045em;font-variant-numeric:tabular-nums}.result-unit{color:var(--text-muted);font-size:1rem;font-weight:600}.result-sub{font-size:1rem;font-weight:650;color:var(--success)}.result-empty{color:var(--text-muted);font-style:italic}.result-details{display:grid;grid-template-columns:repeat(3,1fr);margin-top:1.5rem;border-top:1px solid var(--border)}.result-dt{padding:.9rem 1rem 0}.result-dt+.result-dt{border-left:1px solid var(--border)}.result-dt dt{color:var(--text-muted);font-size:.69rem;font-weight:750;text-transform:uppercase;letter-spacing:.06em}.result-dt dd{margin:.2rem 0 0;font-size:1rem;font-weight:650;color:var(--text-strong);font-variant-numeric:tabular-nums}.chart-controls{display:flex;flex-wrap:wrap;gap:.75rem;align-items:flex-end;padding:1rem;border:1px solid var(--border);border-radius:var(--radius-md) var(--radius-md) 0 0;background:var(--surface)}.chart-controls .field{margin-bottom:0;min-width:150px;flex:1}.chart-actions{display:flex;gap:.5rem}.table-wrap{border:1px solid var(--border);background:var(--surface);overflow-x:auto}.data-table{width:100%;border-collapse:collapse;font-variant-numeric:tabular-nums}.data-table th,.data-table td{padding:.58rem .75rem;border-bottom:1px solid var(--border)}.data-table th{background:#f8fafc;color:var(--text-muted);font-size:.69rem;font-weight:750;letter-spacing:.065em;text-transform:uppercase}.data-table td:first-child,.data-table th:first-child{text-align:left}.data-table td:not(:first-child),.data-table th:not(:first-child){text-align:right}.data-table tbody tr:nth-child(2n){background:#fbfcfd}.data-table tbody tr:hover{background:var(--accent-soft)}.chart-page main .container{padding:2.5rem 0 3rem}.chart-title{font-size:clamp(1.7rem,3.2vw,2.3rem);font-weight:750;letter-spacing:-.025em;line-height:1.15}.chart-dims{margin:.35rem 0 1.25rem;font-size:.9rem;line-height:1.5;color:var(--text-muted)}.chart-note{margin:1rem 0 0;color:var(--warning);font-weight:600}.chart-note:empty,.chart-dims:empty{display:none}.chart-page .chart-actions{margin-top:1.25rem;flex-wrap:wrap}.chart-back{margin-left:.75rem;font-size:.92rem}.page-header p:not(.eyebrow),.hero p:not(.eyebrow){color:var(--text-muted);max-width:62ch}.content p{max-width:75ch;color:var(--text)}.formula{margin:1rem 0;padding:.8rem 1rem;background:var(--surface-alt);border:1px solid var(--border);border-radius:4px;overflow-x:auto}.formula code{font-size:.92rem;white-space:nowrap}.dip-steps{margin:1rem 0;padding-left:1.25rem;display:grid;gap:.5rem}.fine-print{color:var(--text-muted);font-size:.82rem}.hero{padding:3.75rem 0 3rem}.hero-logo{display:block;width:70%;height:auto;margin:0 auto 1.75rem}.hero p{font-size:1rem}.tool-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(220px,1fr));gap:1rem}.tool-card{display:flex;flex-direction:column;gap:.7rem;padding:1.25rem;background:#fff;border:1px solid var(--border);border-radius:var(--radius-md);color:var(--text);text-decoration:none;transition:border-color .15s ease,background-color .15s ease}.tool-card:hover{border-color:#b9c9dc;background:#fbfdff}.tool-card .tool-svg{height:130px;width:100%}.tool-card h3{margin:0}.tool-card p{margin:0;color:var(--text-muted);font-size:.86rem;line-height:1.5;flex:1}.tool-card .tool-link{margin-top:.35rem;color:var(--accent);font-size:.82rem;font-weight:650}.contact-form{display:grid;gap:1rem;max-width:34rem;margin-top:1.5rem}.contact-note{color:var(--warning);font-weight:600;font-size:.9rem}.no-print[hidden]{display:none}.site-footer{margin-top:3rem;background:var(--nav);border-top:1px solid rgb(255 255 255 / 8%);padding:1.5rem 0;color:var(--nav-muted);font-size:.88rem}.site-footer a{color:#c9d2df}.site-footer a:hover{color:#fff}.site-footer .container{display:flex;flex-wrap:wrap;gap:.5rem 1.5rem;justify-content:space-between}.site-footer ul{margin:0;padding:0;list-style:none;display:flex;flex-wrap:wrap;gap:.25rem 1rem}.disclaimer{max-width:75ch}@media(max-width:800px){.calculator-grid{grid-template-columns:1fr}.calculator-grid>.col+.col{border-left:0;border-top:1px solid var(--border)}.result-details{grid-template-columns:1fr}.result-dt+.result-dt{border-left:0;border-top:1px solid var(--border)}.button-row .button-primary,.button-row .button-secondary,.chart-actions,.chart-actions .button-secondary{flex:1}}@media(prefers-reduced-motion:reduce){*{transition:none!important}}@media print{body{background:#fff;color:#000}.no-print{display:none!important}.panel,.chart-controls,.table-wrap{box-shadow:none}.diagram-wrap{background:#fff}.site-footer{background:#fff;color:#000;border-top:1px solid #000}.result-value{font-size:2rem}.chart-page main .container{padding:0}.chart-dims{color:#000}.data-table th,.data-table td{border-color:#000}}