:root{color-scheme:light;--ink:#142e43;--muted:#526575;--line:#dce4e9;--accent:#bf4b20;--paper:#f5f8fa;--blue:#244d67}*{box-sizing:border-box}body{margin:0;color:var(--ink);background:#fff;font:17px/1.7 system-ui,-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif}a{color:#1d607c;text-underline-offset:4px}a:hover{text-decoration-thickness:2px}.wrap{width:min(1120px,calc(100% - 48px));margin:auto}.site-header{display:flex;align-items:center;justify-content:space-between;padding:25px 0;border-bottom:1px solid var(--line)}.brand{display:flex;gap:12px;align-items:center;font-size:17px;font-weight:750;line-height:1.2;text-decoration:none;color:var(--ink)}.brand-small{display:block;font-size:10px;letter-spacing:3px;margin-top:5px}.header-note{font-size:14px;color:var(--muted)}.intro{padding:35px 0 24px}.eyebrow{font-size:12px;letter-spacing:1.8px;font-weight:750;color:var(--accent);margin:0 0 9px}h1,h2,h3{line-height:1.22;letter-spacing:-.035em}h1{font-size:clamp(30px,4.5vw,49px);margin:0 0 10px;font-weight:750}.intro>p:last-child{margin:0;color:var(--muted)}.calculator{display:grid;grid-template-columns:1fr 1.12fr;border:1px solid var(--line);border-radius:18px;overflow:hidden;box-shadow:0 12px 40px #142e4308}form{padding:30px}label{display:block;font-size:15px;font-weight:650}.required{font-weight:400;color:var(--muted);font-size:13px}input[type=text]{display:block;width:100%;min-height:48px;border:1px solid #a7b9c5;border-radius:7px;margin-top:8px;padding:10px 14px;font:18px/1.4 inherit;font-family:inherit;font-size:18px;color:var(--ink);background:#fff}input[aria-invalid=true]{border:2px solid #a93320}input::placeholder{color:#657785}input[type=checkbox]{width:18px;height:18px;margin:0;accent-color:var(--blue);flex-shrink:0}.check{display:flex;align-items:center;gap:9px;cursor:pointer;font-size:14px;font-weight:500;min-height:32px}.hint{font-size:12px;line-height:1.5;color:var(--muted);margin:6px 0 12px}.options{margin:12px 0 18px}#ovulation-fields{padding:8px 0}button{width:100%;border:0;border-radius:7px;background:var(--ink);color:#fff;min-height:48px;padding:12px 17px;font:650 16px/1.4 system-ui;cursor:pointer;display:flex;justify-content:space-between;align-items:center}button:hover{background:#244d67}.privacy{font-size:12px;margin:12px 0 0;color:var(--muted)}.error{font-size:14px;color:#a12c18;line-height:1.5;margin:8px 0 0}.error:empty{display:none}.result{background:var(--paper);padding:38px 34px;display:flex;flex-direction:column;justify-content:center;border-left:1px solid var(--line)}.due-date{font-size:clamp(27px,3.8vw,43px);letter-spacing:-.04em;line-height:1.2;font-weight:750;margin:0 0 10px;font-variant-numeric:tabular-nums}.range{font-size:14px;color:var(--muted);margin:0 0 15px}.basis{font-size:14px;margin:0;line-height:1.6}.metrics{display:grid;grid-template-columns:repeat(3,1fr);border-top:1px solid #d5dfe5;border-bottom:1px solid #d5dfe5;padding:20px 0;margin:23px 0 15px;gap:12px}.metrics strong{display:block;font-size:29px;line-height:1.2;font-weight:650}.metrics span{display:block;font-size:12px;margin-top:8px;color:var(--muted)}.result-note{margin:0;font-size:13px;line-height:1.6}.result-note.warning{color:#923317;font-weight:600}.reading{padding-top:25px}.reading section{padding:48px 0;border-bottom:1px solid var(--line)}h2{font-size:clamp(26px,3vw,34px);margin:0 0 24px}h3{font-size:20px;margin:28px 0 10px;letter-spacing:-.02em}p{margin:0 0 18px}.reading p{max-width:84ch}.reading section>p,.range-section p{color:#3f5363}.section-number{margin-bottom:12px!important;color:var(--accent)!important}.range-section{display:grid;grid-template-columns:1.25fr 1fr;align-items:center;gap:40px}figure{margin:0}figure img{display:block;width:100%;height:auto;border-radius:12px}figcaption{color:var(--muted);font-size:12px;line-height:1.5;margin-top:10px}.timeline-layout{display:grid;grid-template-columns:.9fr 1.4fr;gap:48px;align-items:center}.timeline{border-left:2px solid #e4e9ec;padding-left:25px}.timeline>div{position:relative}.timeline>div:before{content:"";position:absolute;left:-32px;top:7px;width:12px;height:12px;border:3px solid #fff;border-radius:50%;background:var(--accent);box-shadow:0 0 0 1px #d6b5a7}.timeline h3{font-size:18px;letter-spacing:-.02em;margin-top:22px}.timeline p{font-size:15px;color:#3f5363;line-height:1.65}.faq>div{padding:6px 0 13px;border-bottom:1px solid var(--line)}.faq>div:last-of-type{border:0}.source-note{font-size:13px;margin-top:20px}.notice{padding:18px;background:#fff3e8;margin-top:20px}footer{padding:30px 0 36px!important;font-size:12px;color:var(--muted);display:flex;gap:50px;justify-content:space-between}footer p{max-width:720px;margin:0}footer span{white-space:nowrap}.skip{position:absolute;top:-100px;background:#fff;padding:12px;z-index:9}.skip:focus{top:0}:focus-visible{outline:3px solid #cd672c;outline-offset:4px}[hidden]{display:none!important}@media(max-width:760px){.wrap{width:calc(100% - 32px)}.site-header{padding:17px 0}.header-note{display:none}.intro{padding:24px 0 18px}.intro>p:last-child{font-size:14px}.eyebrow{font-size:10px}.calculator{grid-template-columns:1fr}.calculator form{padding:20px}.result{border-left:0;border-top:1px solid var(--line);padding:22px}.due-date{font-size:31px}.metrics{padding:14px 0;margin:16px 0 12px}.metrics strong{font-size:25px}.reading section{padding:34px 0}.range-section,.timeline-layout{grid-template-columns:1fr;gap:24px}.range-section figure,.timeline-layout figure{max-width:450px;margin:auto;width:100%}.timeline-layout figure{order:2}h2{margin-bottom:18px}h3{font-size:19px}footer{display:block}footer span{display:block;margin-top:16px}.reading{padding-top:10px}}@media(prefers-reduced-motion:no-preference){button{transition:background .15s}}
/* Date controls preserve the explicit US text format while exposing a native calendar. */
.input-wrap{position:relative}.input-wrap input[type=text]{padding-right:58px}.calendar-control{position:absolute;right:2px;top:2px;width:44px;height:44px;display:grid;place-items:center;border-left:1px solid var(--line);color:var(--blue);font-size:27px;line-height:1;cursor:pointer}.calendar-control input{position:absolute;inset:0;width:100%;height:100%;opacity:0;cursor:pointer}.calendar-control input::-webkit-calendar-picker-indicator{position:absolute;inset:0;width:100%;height:100%;margin:0;padding:0;cursor:pointer}.calendar-control:focus-within{outline:3px solid #cd672c;outline-offset:2px;border-radius:4px}
@media(max-width:760px){.site-header{padding:12px 0}.brand{font-size:15px}.intro{padding:14px 0 12px}.intro .eyebrow{margin-bottom:6px}h1{font-size:28px;line-height:1.12;margin-bottom:6px}.intro>p:last-child{font-size:13px;line-height:1.5}.calculator form{padding:16px}.options{margin:8px 0 10px}.check{min-height:28px}.hint{margin:4px 0 8px}.privacy{font-size:11px;line-height:1.5;margin-top:8px}.result{padding:16px}.range{margin-bottom:10px}.metrics{margin:12px 0 10px}}
@media(max-width:360px){.intro .eyebrow,.intro>p:last-child{display:none}.intro{padding:12px 0}.intro h1{font-size:26px;margin-bottom:0}.calculator form{padding:14px}.site-header{padding:10px 0}}
/* Anchor the native calendar to the whole field so its popup fits narrow screens. */
.calendar-control{left:0;right:0;width:100%;border-left:0;pointer-events:none}.calendar-control>span{display:grid;place-items:center;margin-left:auto;width:44px;height:40px;border-left:1px solid var(--line)}.calendar-control input{pointer-events:none}.calendar-control input::-webkit-calendar-picker-indicator{left:auto;right:0;width:44px;pointer-events:auto}