.toolkit-page{background:#fff;color:var(--engineering-ink)}
.toolkit-page .site-header{color:#f5f5f5}
.toolkit-page .wordmark{color:#f5f5f5}
.toolkit-page .breadcrumb{color:var(--engineering-muted);flex-wrap:wrap;overflow-wrap:anywhere}
.toolkit-page .light-section{background:#fff;color:var(--engineering-ink)}
.toolkit-navigation{display:flex;flex-wrap:wrap;gap:8px;padding-top:12px;padding-bottom:16px}
.toolkit-navigation a{display:flex;align-items:center;min-height:44px;padding:10px 14px;border:1px solid var(--engineering-rule);border-radius:0;background:var(--engineering-panel);color:var(--engineering-icon);font-size:.875rem;line-height:1.35}
.toolkit-navigation a[aria-current=page]{background:var(--engineering-accent);border-color:var(--engineering-accent);color:#fff}
.toolkit-navigation a:hover{border-color:#777777}
.toolkit-page a:focus-visible,.calculator-input:focus-visible,.calculator-submit:focus-visible{outline:3px solid var(--engineering-focus);outline-offset:3px}
.toolkit-hero{padding:28px 0 36px;border-bottom:1px solid var(--engineering-border)}
.toolkit-page .eyebrow{color:var(--engineering-muted);font-size:.8rem}
.toolkit-hero h1{max-width:1100px;margin-top:14px;font-size:clamp(1.8rem,3.3vw,3rem);line-height:1.15;color:var(--engineering-ink)}
.toolkit-lead{max-width:820px;margin-top:18px;color:var(--engineering-muted);font-size:1rem;line-height:1.75}
.toolkit-directory,.calculator-section{padding-top:36px;padding-bottom:56px}
.tool-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:0;border-top:1px solid var(--engineering-rule);border-left:1px solid var(--engineering-rule)}
.tool-card{min-width:0;min-height:330px;padding:30px;display:flex;flex-direction:column;border:0;border-right:1px solid var(--engineering-rule);border-bottom:1px solid var(--engineering-rule);background:var(--engineering-panel);transition:background .18s}
.tool-card:hover{background:#f7f7f7}
.tool-card-top{display:flex;align-items:center;justify-content:space-between;gap:16px}
.tool-card-icon{width:32px;height:32px;flex-shrink:0;color:var(--engineering-icon)}
.tool-card-top .eyebrow{text-align:right;font-size:.75rem}
.tool-card h2{font-size:1.4rem;line-height:1.35;margin:26px 0 18px;color:var(--engineering-ink)}
.tool-card p{margin-bottom:30px;color:var(--engineering-muted);font-size:1rem;line-height:1.65}
.tool-card-link{margin-top:auto;padding-top:20px;border-top:1px solid #e6e6e6;display:flex;align-items:center;justify-content:space-between;gap:20px;font-size:.9rem;font-weight:650;color:var(--engineering-icon)}
.tool-card-link svg{width:18px;height:18px;flex-shrink:0}
.toolkit-principles,.toolkit-detail{border-top:1px solid var(--engineering-border);background:#fff}
.toolkit-copy-grid{display:grid;grid-template-columns:.85fr 1.35fr;gap:50px}
.toolkit-copy-grid h2{margin-top:16px;font-size:1.8rem;line-height:1.2;color:var(--engineering-ink)}
.toolkit-copy-grid p{font-size:1rem;line-height:1.75;color:var(--engineering-muted)}
.calculator-layout{display:grid;grid-template-columns:minmax(0,1.12fr) minmax(0,1fr);gap:24px;align-items:start}
.calculator-panel,.calculator-results,.calculator-method{min-width:0;background:var(--engineering-panel);border:1px solid var(--engineering-border);border-radius:0;padding:28px;color:var(--engineering-ink)}
.calculator-panel h2,.calculator-results h2,.calculator-method h2{font-size:1.35rem;line-height:1.3;margin-bottom:20px}
.calculator-modes{display:flex;flex-wrap:wrap;gap:8px;margin-bottom:24px}
.calculator-modes a{display:flex;align-items:center;min-height:44px;border:1px solid var(--engineering-rule);border-radius:0;background:#fff;padding:10px 12px;font-size:.875rem;line-height:1.4;color:var(--engineering-icon)}
.calculator-modes a[aria-current=page]{background:var(--engineering-accent);border-color:var(--engineering-accent);color:#fff}
.calculator-fields{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:20px}
.calculator-field label{display:block;font-size:.9rem;line-height:1.45;font-weight:650;margin-bottom:8px}
.toolkit-page .calculator-panel .calculator-form .calculator-input{width:100%;min-height:50px;padding:11px 12px;border:1px solid #c8c8c8;border-radius:0;background:#fff;color:var(--engineering-ink);font-size:1rem}
.toolkit-page .calculator-panel .calculator-form .calculator-input[aria-invalid=true]{border-color:var(--engineering-focus)}
.calculator-input::-webkit-inner-spin-button,.calculator-input::-webkit-outer-spin-button{-webkit-appearance:none;margin:0}
.calculator-input[type=number]{-moz-appearance:textfield;appearance:textfield}
.field-help{font-size:.8125rem;color:var(--engineering-muted);margin-top:7px;line-height:1.55;overflow-wrap:anywhere}
.field-help:empty{display:none}
.field-error,.calculator-error{color:var(--engineering-icon);font-size:.875rem;line-height:1.5;margin-top:8px}
.field-error ul,.calculator-error ul{margin:0;padding-left:18px}
.calculator-error{margin:0 0 18px}
.calculator-submit{margin-top:28px;min-width:180px;min-height:48px;background:var(--engineering-accent)!important;color:#fff!important;border-radius:0}
.calculator-status{color:var(--engineering-muted);font-size:.875rem;min-height:1.5em;margin-top:10px}
.calculator-output{display:grid;gap:24px;min-width:0}
.calculator-results h2{margin-top:10px}
.calculator-results dl{margin:0;display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:12px}
.calculator-results dl>div{background:#fff;border:1px solid var(--engineering-border);border-radius:0;padding:18px;min-width:0}
.calculator-results dt{font-size:.875rem;line-height:1.45;color:var(--engineering-muted)}
.calculator-results dd{margin:8px 0 0;font-size:1.4rem;line-height:1.3;font-weight:650;letter-spacing:-.02em;overflow-wrap:anywhere;color:var(--engineering-ink)}
.result-prompt{color:var(--engineering-muted);font-size:1rem;line-height:1.6}
.results-note{font-size:.8125rem;line-height:1.6;color:var(--engineering-muted);margin-top:18px}
.calculator-method h2{margin:10px 0 18px}
.equation-slot{min-height:130px;display:flex;align-items:center;justify-content:center;margin-bottom:24px;border:1px dashed #c8c8c8;border-radius:0;background:#fff;padding:18px;text-align:center;color:#777777;font-size:.875rem}
.equation-slot img{display:block;width:100%;height:auto;object-fit:contain}
.calculator-method h3{font-size:1rem;margin-bottom:12px}
.calculator-method ul{padding-left:20px;margin:0;color:var(--engineering-muted);font-size:.9rem;line-height:1.7}
.calculator-method li+li{margin-top:10px}
.tool-steps{list-style:none;margin:0;padding:0;border-top:1px solid var(--engineering-border)}
.tool-steps li{display:grid;grid-template-columns:30px 1fr;gap:18px;padding:18px 0;border-bottom:1px solid var(--engineering-border)}
.tool-steps li>span{font-size:.8125rem;color:var(--engineering-muted)}
.toolkit-references{border-top:1px solid var(--engineering-border);background:#fff}
.book-reference-list{display:grid;gap:18px;min-width:0}
.book-reference{display:flex;align-items:flex-start;gap:24px;background:var(--engineering-panel);border:1px solid var(--engineering-rule);padding:28px;min-width:0}
.book-cover{width:100px;max-height:160px;height:auto;object-fit:contain;flex-shrink:0}
.book-reference-copy{min-width:0}
.book-reference h3{font-size:1.2rem;line-height:1.4;letter-spacing:-.02em;color:var(--engineering-ink)}
.book-reference p{font-size:.9rem;line-height:1.7;margin-top:8px;color:var(--engineering-muted)}
.book-reference .book-isbn{font-size:.8125rem;color:var(--engineering-muted)}
.book-source{display:inline-flex;align-items:center;min-height:44px;margin-top:10px;font-size:.9rem;font-weight:650;color:var(--engineering-icon);text-decoration:underline;text-underline-offset:4px}
.toolkit-page [hidden]{display:none!important}
@media(max-width:1000px){.tool-grid{grid-template-columns:repeat(2,minmax(0,1fr))}.calculator-layout{grid-template-columns:1fr}.calculator-output{grid-template-columns:1fr 1fr}.calculator-results dl{grid-template-columns:1fr}}
@media(max-width:700px){.toolkit-navigation{display:grid;grid-template-columns:repeat(2,minmax(0,1fr))}.toolkit-navigation a{font-size:.8125rem;padding:10px;overflow-wrap:anywhere}.toolkit-hero{padding:24px 0 28px}.tool-grid,.calculator-fields,.calculator-output,.calculator-results dl,.toolkit-copy-grid{grid-template-columns:1fr}.toolkit-copy-grid{gap:28px}.tool-card{min-height:230px;padding:24px}.calculator-panel,.calculator-results,.calculator-method{padding:22px}.calculator-modes{display:grid;grid-template-columns:1fr}.calculator-submit{width:100%}.calculator-results dd{font-size:1.3rem}.toolkit-directory,.calculator-section{padding-top:28px}}

@media(max-width:700px){.book-reference{padding:22px;gap:18px}.book-cover{width:75px;max-height:120px}.tool-card-top .eyebrow{font-size:.75rem}.tool-card{min-height:300px}}
@media(max-width:360px){.book-reference{flex-direction:column}}