:root{--color-bg: #ffffff;--color-surface: #f7f9fb;--color-surface-2: #eef2f6;--color-border: #dce3ea;--color-text: #1f2933;--color-text-muted: #52606d;--color-primary: #1565c0;--color-primary-dark: #0d47a1;--color-primary-contrast: #ffffff;--color-underweight: #2f80ed;--color-healthy: #1e8e5a;--color-overweight: #c77700;--color-obesity: #c0392b;--color-success-bg: #e7f4ec;--color-warning-bg: #fdf3e2;--color-error: #b3261e;--color-error-bg: #fdecea;--font-sans: system-ui, -apple-system, "Segoe UI", Roboto, Helvetica, Arial, "Apple Color Emoji", "Segoe UI Emoji", sans-serif;--font-size-base: 1rem;--line-height: 1.65;--maxw: 760px;--maxw-wide: 1080px;--radius: 12px;--radius-sm: 8px;--space-1: .25rem;--space-2: .5rem;--space-3: .75rem;--space-4: 1rem;--space-5: 1.5rem;--space-6: 2rem;--space-8: 3rem;--shadow-sm: 0 1px 2px rgba(15, 23, 42, .06);--shadow: 0 4px 16px rgba(15, 23, 42, .08);--focus-ring: 0 0 0 3px rgba(21, 101, 192, .35);color-scheme:light}:root[data-theme=dark]{color-scheme:dark;--color-bg: #0f1621;--color-surface: #161f2b;--color-surface-2: #1f2a38;--color-border: #2c3a4b;--color-text: #e6edf3;--color-text-muted: #9fb0c0;--color-primary: #6db1ff;--color-primary-dark: #8cc2ff;--color-primary-contrast: #0b1220;--color-underweight: #5a9ff5;--color-healthy: #34c98a;--color-overweight: #e8a13c;--color-obesity: #ef6b5e;--color-success-bg: #14352a;--color-warning-bg: #38301a;--color-error: #ff7a72;--color-error-bg: #3a1f1f;--shadow-sm: 0 1px 2px rgba(0, 0, 0, .4);--shadow: 0 4px 16px rgba(0, 0, 0, .5);--focus-ring: 0 0 0 3px rgba(109, 177, 255, .45)}:root[data-theme=dark] .brand .mark{color:var(--color-primary-contrast)}:root[data-theme=dark] .callout.warning{border-color:#5a4a24}*,*:before,*:after{box-sizing:border-box}html{-webkit-text-size-adjust:100%;scroll-behavior:smooth}body{margin:0;font-family:var(--font-sans);font-size:var(--font-size-base);line-height:var(--line-height);color:var(--color-text);background:var(--color-bg);display:flex;flex-direction:column;min-height:100vh}img{max-width:100%;height:auto}a{color:var(--color-primary);text-decoration:underline;text-underline-offset:2px}a:hover{color:var(--color-primary-dark)}h1,h2,h3{line-height:1.25;color:var(--color-text)}h1{font-size:clamp(1.7rem,5vw,2.4rem);margin:0 0 var(--space-3)}h2{font-size:clamp(1.3rem,3.5vw,1.6rem);margin:var(--space-8) 0 var(--space-3)}h3{font-size:1.1rem;margin:var(--space-5) 0 var(--space-2)}p{margin:0 0 var(--space-4)}.container{width:100%;max-width:var(--maxw);margin-inline:auto;padding-inline:var(--space-4)}.container-wide{max-width:var(--maxw-wide)}main{flex:1 0 auto;padding-block:var(--space-6)}.lead{font-size:1.1rem;color:var(--color-text-muted)}.section{margin-top:var(--space-6)}.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}.skip-link{position:absolute;left:var(--space-2);top:-3rem;background:var(--color-primary);color:var(--color-primary-contrast);padding:var(--space-2) var(--space-3);border-radius:var(--radius-sm);z-index:100;transition:top .15s ease}.skip-link:focus{top:var(--space-2)}:focus-visible{outline:2px solid var(--color-primary);outline-offset:2px}.site-header{border-bottom:1px solid var(--color-border);background:var(--color-bg)}.site-header .bar{display:flex;align-items:center;justify-content:space-between;flex-wrap:wrap;gap:var(--space-4);padding-block:var(--space-3)}.brand{font-weight:700;font-size:1.15rem;text-decoration:none;color:var(--color-text);display:inline-flex;align-items:center;gap:var(--space-2);margin-right:auto}.brand .mark{display:inline-grid;place-items:center;width:28px;height:28px;border-radius:7px;background:var(--color-primary);color:#fff;font-size:.8rem;font-weight:700}.site-nav ul{list-style:none;display:flex;flex-wrap:wrap;gap:var(--space-3);margin:0;padding:0;font-size:.95rem}.site-nav a{text-decoration:none;color:var(--color-text-muted);padding-bottom:3px;border-bottom:2px solid transparent}.site-nav a:hover{color:var(--color-primary)}.site-nav a[aria-current=page]{color:var(--color-primary);font-weight:700;border-bottom-color:var(--color-primary)}.nav-toggle,.theme-toggle{align-items:center;justify-content:center;width:44px;height:44px;padding:0;border:1px solid var(--color-border);border-radius:var(--radius-sm);background:var(--color-bg);color:var(--color-text);cursor:pointer}.nav-toggle:hover,.theme-toggle:hover{border-color:var(--color-primary);color:var(--color-primary)}.theme-toggle{display:inline-flex}.theme-toggle svg{width:20px;height:20px}.theme-toggle .icon-sun{display:none}:root[data-theme=dark] .theme-toggle .icon-sun{display:block}:root[data-theme=dark] .theme-toggle .icon-moon{display:none}.nav-toggle{display:none}.nav-toggle-bars,.nav-toggle-bars:before,.nav-toggle-bars:after{content:"";display:block;width:22px;height:2px;background:currentColor;border-radius:2px;transition:transform .2s ease,opacity .2s ease}.nav-toggle-bars{position:relative}.nav-toggle-bars:before{position:absolute;top:-7px}.nav-toggle-bars:after{position:absolute;top:7px}.nav-toggle[aria-expanded=true] .nav-toggle-bars{background:transparent}.nav-toggle[aria-expanded=true] .nav-toggle-bars:before{top:0;transform:rotate(45deg)}.nav-toggle[aria-expanded=true] .nav-toggle-bars:after{top:0;transform:rotate(-45deg)}@media(max-width:879px){.site-nav{flex-basis:100%;order:3}.site-nav ul{flex-direction:column;gap:var(--space-1);margin-top:var(--space-2)}.site-nav li a{display:block;padding:var(--space-3) var(--space-2);border-radius:var(--radius-sm)}.site-nav a[aria-current=page]{background:var(--color-surface-2)}.js .nav-toggle{display:inline-flex}.js .site-nav{display:none}.js .site-nav.open{display:block}}.breadcrumbs{font-size:.85rem;color:var(--color-text-muted);margin-bottom:var(--space-4)}.breadcrumbs ol{list-style:none;display:flex;flex-wrap:wrap;gap:var(--space-1);margin:0;padding:0}.breadcrumbs li:after{content:"/";margin-inline:var(--space-2);color:var(--color-border)}.breadcrumbs li:last-child:after{content:""}.breadcrumbs a{text-decoration:none}.bmi-calc{background:var(--color-surface);border:1px solid var(--color-border);border-radius:var(--radius);padding:var(--space-5);box-shadow:var(--shadow-sm)}.unit-toggle{display:inline-flex;background:var(--color-surface-2);border:1px solid var(--color-border);border-radius:999px;padding:3px;margin-bottom:var(--space-4)}.unit-toggle button{appearance:none;border:0;background:transparent;padding:var(--space-2) var(--space-4);border-radius:999px;font:inherit;cursor:pointer;color:var(--color-text-muted)}.unit-toggle button[aria-pressed=true]{background:var(--color-bg);color:var(--color-primary);font-weight:600;box-shadow:var(--shadow-sm)}.field-grid{display:grid;grid-template-columns:1fr;gap:var(--space-4)}@media(min-width:480px){.field-grid.two{grid-template-columns:1fr 1fr}}.field{display:flex;flex-direction:column;gap:var(--space-1)}.field label{font-weight:600;font-size:.95rem}.field .hint{font-size:.8rem;color:var(--color-text-muted)}.field input,.field select{font:inherit;padding:var(--space-3);border:1px solid var(--color-border);border-radius:var(--radius-sm);background:var(--color-bg);color:var(--color-text);min-height:44px}.field input:focus,.field select:focus{outline:none;border-color:var(--color-primary);box-shadow:var(--focus-ring)}.field input[aria-invalid=true]{border-color:var(--color-error)}.height-us{display:grid;grid-template-columns:1fr 1fr;gap:var(--space-3)}fieldset{border:0;margin:0;padding:0}fieldset legend{font-weight:600;font-size:.95rem;padding:0;margin-bottom:var(--space-1)}.actions{display:flex;flex-wrap:wrap;gap:var(--space-3);margin-top:var(--space-5)}.btn{appearance:none;font:inherit;font-weight:600;cursor:pointer;border-radius:var(--radius-sm);padding:var(--space-3) var(--space-5);border:1px solid transparent;min-height:44px}.btn-primary{background:var(--color-primary);color:var(--color-primary-contrast)}.btn-primary:hover{background:var(--color-primary-dark)}.btn-secondary{background:var(--color-bg);color:var(--color-primary);border-color:var(--color-border)}.btn-secondary:hover{background:var(--color-surface-2)}.form-error{margin-top:var(--space-4);padding:var(--space-3);background:var(--color-error-bg);border:1px solid var(--color-error);border-radius:var(--radius-sm);color:var(--color-error);font-size:.95rem}.result{margin-top:var(--space-5);padding:var(--space-5);border-radius:var(--radius);background:var(--color-bg);border:1px solid var(--color-border);border-left:6px solid var(--color-primary)}.result[hidden]{display:none}.result .bmi-number{font-size:clamp(2.2rem,8vw,3rem);font-weight:800;line-height:1;margin:0}.result .bmi-category{font-size:1.1rem;font-weight:700;margin:var(--space-2) 0}.result .bmi-explain{color:var(--color-text-muted);margin-bottom:var(--space-3)}.result .bmi-formula{font-size:.85rem;color:var(--color-text-muted);background:var(--color-surface);border-radius:var(--radius-sm);padding:var(--space-2) var(--space-3);display:inline-block}.result-tools{margin-top:var(--space-4);display:flex;gap:var(--space-3);flex-wrap:wrap}.copy-status{font-size:.85rem;color:var(--color-healthy);align-self:center}.result.cat-underweight{border-left-color:var(--color-underweight)}.result.cat-healthy{border-left-color:var(--color-healthy)}.result.cat-overweight{border-left-color:var(--color-overweight)}.result.cat-obesity{border-left-color:var(--color-obesity)}.result.cat-child{border-left-color:var(--color-primary)}.result.cat-underweight .bmi-category{color:var(--color-underweight)}.result.cat-healthy .bmi-category{color:var(--color-healthy)}.result.cat-overweight .bmi-category{color:var(--color-overweight)}.result.cat-obesity .bmi-category{color:var(--color-obesity)}.bmi-gauge{margin:0 auto var(--space-4);max-width:320px}.bmi-gauge[hidden]{display:none}.bmi-gauge svg{display:block;width:100%;height:auto;overflow:visible}.gauge-band{fill:none;stroke-width:20;stroke-linecap:butt}.gauge-band.underweight{stroke:var(--color-underweight)}.gauge-band.healthy{stroke:var(--color-healthy)}.gauge-band.overweight{stroke:var(--color-overweight)}.gauge-band.obesity{stroke:var(--color-obesity)}.gauge-tick{fill:var(--color-text-muted);font-size:9px;font-weight:600;text-anchor:middle;dominant-baseline:middle}.gauge-needle{fill:var(--color-text);transform-box:view-box;transform-origin:100px 100px;transition:transform .9s cubic-bezier(.22,.8,.28,1)}.gauge-hub{fill:var(--color-text)}@media(prefers-reduced-motion:reduce){.gauge-needle{transition:none}}.child-notice{margin-top:var(--space-3);padding:var(--space-3);background:var(--color-warning-bg);border-radius:var(--radius-sm);font-size:.92rem}.table-wrap{overflow-x:auto;border:1px solid var(--color-border);border-radius:var(--radius)}table.bmi-table{width:100%;border-collapse:collapse;font-size:.95rem}table.bmi-table th,table.bmi-table td{text-align:left;padding:var(--space-3);border-bottom:1px solid var(--color-border)}table.bmi-table thead th{background:var(--color-surface-2)}table.bmi-table tr:last-child td{border-bottom:0}.swatch{display:inline-block;width:12px;height:12px;border-radius:3px;margin-right:var(--space-2);vertical-align:middle}.faq details{border:1px solid var(--color-border);border-radius:var(--radius-sm);padding:var(--space-3) var(--space-4);margin-bottom:var(--space-3);background:var(--color-bg)}.faq summary{cursor:pointer;font-weight:600;list-style:none}.faq summary::-webkit-details-marker{display:none}.faq summary:after{content:"+";float:right;color:var(--color-primary);font-weight:700}.faq details[open] summary:after{content:"-"}.faq details[open] summary{margin-bottom:var(--space-2)}.card-grid{display:grid;grid-template-columns:1fr;gap:var(--space-4)}@media(min-width:560px){.card-grid{grid-template-columns:1fr 1fr}}.card{display:block;padding:var(--space-4);border:1px solid var(--color-border);border-radius:var(--radius);text-decoration:none;color:var(--color-text);background:var(--color-bg);transition:border-color .15s ease,box-shadow .15s ease}.card:hover{border-color:var(--color-primary);box-shadow:var(--shadow-sm);color:var(--color-text)}.card .card-title{font-weight:700;color:var(--color-primary);margin-bottom:var(--space-1)}.card .card-desc{font-size:.9rem;color:var(--color-text-muted)}.sources ul{list-style:none;padding:0;margin:0;display:grid;gap:var(--space-3)}.sources li{padding:var(--space-3);border:1px solid var(--color-border);border-radius:var(--radius-sm);background:var(--color-surface)}.sources .src-note{font-size:.85rem;color:var(--color-text-muted);margin-top:var(--space-1)}.callout{padding:var(--space-4);border-radius:var(--radius);border:1px solid var(--color-border);background:var(--color-surface);margin-block:var(--space-4)}.callout.warning{background:var(--color-warning-bg);border-color:#f0d9a8}.callout .callout-title{font-weight:700;margin-bottom:var(--space-1)}.ad-slot{margin-block:var(--space-6);display:flex;align-items:center;justify-content:center;min-height:90px;border:1px dashed var(--color-border);border-radius:var(--radius-sm);background:repeating-linear-gradient(45deg,var(--color-surface),var(--color-surface) 12px,var(--color-surface-2) 12px,var(--color-surface-2) 24px);color:var(--color-text-muted);font-size:.85rem;letter-spacing:.04em;text-transform:uppercase}.tabs{margin-top:var(--space-4)}.tablist{display:flex;gap:var(--space-2);flex-wrap:wrap;border-bottom:2px solid var(--color-border);margin-bottom:var(--space-4)}.tablist button{appearance:none;border:0;background:transparent;font:inherit;font-weight:600;padding:var(--space-3) var(--space-4);cursor:pointer;color:var(--color-text-muted);border-bottom:3px solid transparent;margin-bottom:-2px}.tablist button[aria-selected=true]{color:var(--color-primary);border-bottom-color:var(--color-primary)}.tabpanel[hidden]{display:none}.site-footer{border-top:1px solid var(--color-border);background:var(--color-surface);margin-top:var(--space-8);padding-block:var(--space-6);font-size:.9rem;color:var(--color-text-muted)}.footer-cols{display:grid;grid-template-columns:1fr;gap:var(--space-5)}@media(min-width:640px){.footer-cols{grid-template-columns:2fr 1fr 1fr}}.site-footer h2{font-size:.95rem;margin:0 0 var(--space-2);color:var(--color-text)}.site-footer ul{list-style:none;padding:0;margin:0;display:grid;gap:var(--space-2)}.site-footer a{text-decoration:none;color:var(--color-text-muted)}.site-footer a:hover{color:var(--color-primary)}.footer-legal{margin-top:var(--space-5);padding-top:var(--space-4);border-top:1px solid var(--color-border);font-size:.82rem}.prose{max-width:var(--maxw)}.prose ul,.prose ol{margin:0 0 var(--space-4);padding-left:1.4em}.prose li{margin-bottom:var(--space-2)}@media(prefers-reduced-motion:reduce){*{scroll-behavior:auto!important;transition:none!important}}