:root{
  --paper:#f7f5f0; --card:#fff; --ink:#1b1e22; --muted:#596069; --line:#e2ddd2;
  --accent:#0f5c55; --accent-ink:#0b443f; --accent-soft:#e7f0ed; --warn:#8a3b12; --warn-soft:#fbf1e8;
  --serif:"Iowan Old Style","Palatino Linotype",Palatino,"Book Antiqua",Georgia,serif;
  --sans:system-ui,-apple-system,"Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif;
  --radius:10px;
}
*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{margin:0;background:var(--paper);color:var(--ink);font:16px/1.6 var(--sans)}
a{color:var(--accent);text-underline-offset:2px}
a:hover{color:var(--accent-ink)}
:focus-visible{outline:3px solid #f0b429;outline-offset:2px;border-radius:4px}
.skip{position:absolute;left:-999px;top:0;background:var(--ink);color:#fff;padding:.5rem 1rem;z-index:10}
.skip:focus{left:0}
.wrap{max-width:1040px;margin:0 auto;padding:0 20px}

/* header */
.site-head{border-bottom:1px solid var(--line);background:var(--paper)}
.site-head .wrap{display:flex;align-items:center;justify-content:space-between;gap:1rem;min-height:60px}





/* type */
h1,h2,h3{font-family:var(--serif);line-height:1.2;letter-spacing:-.01em}
h1{font-size:clamp(1.75rem,4.5vw,2.5rem);margin:.2em 0 .35em}
h2{font-size:1.45rem;margin:2.2rem 0 .6rem;padding-top:.4rem}
h3{font-size:1.1rem;margin:1.4rem 0 .4rem}
.lede{font-size:1.1rem;color:var(--muted);max-width:44rem;margin:0 0 1.5rem}
main{padding:1.2rem 0 3rem}
.crumbs{font-size:.88rem;color:var(--muted);margin-top:.6rem}
.crumbs a{color:var(--muted)}
.prose{max-width:44rem}
.prose li{margin:.25rem 0}

/* calculator */
.tool{display:grid;gap:0;background:var(--card);border:1px solid var(--line);border-radius:var(--radius);overflow:hidden;box-shadow:0 1px 2px rgba(0,0,0,.03)}
@media (min-width:820px){.tool{grid-template-columns:1.15fr 1fr}}
.tool form{padding:1.25rem 1.25rem 1.4rem}
.fields{display:grid;gap:.9rem 1rem;grid-template-columns:1fr}
@media (min-width:520px){.fields{grid-template-columns:1fr 1fr}.fields .full{grid-column:1/-1}}
.field{display:flex;flex-direction:column;gap:.3rem;font-size:.92rem;font-weight:600}
.field small{font-weight:400;color:var(--muted)}
.field input,.field select{font:inherit;font-weight:400;font-size:1rem;padding:.6rem .7rem;border:1px solid #cfc9bc;border-radius:8px;background:#fff;color:var(--ink);min-height:44px;width:100%}
.field input:focus,.field select:focus{border-color:var(--accent);outline:2px solid var(--accent-soft);outline-offset:0}
.check{display:flex;align-items:center;gap:.5rem;font-size:.95rem;min-height:44px}
.check input{width:20px;height:20px;accent-color:var(--accent)}
.btn{font:inherit;font-weight:600;background:var(--accent);color:#fff;border:0;border-radius:8px;padding:.7rem 1.2rem;min-height:44px;cursor:pointer;margin-top:1rem}
.btn:hover{background:var(--accent-ink)}
.btn.ghost{background:transparent;color:var(--accent);border:1px solid var(--accent);margin-right:.5rem}
.result{background:var(--accent-soft);padding:1.25rem 1.3rem 1.4rem;border-top:1px solid var(--line)}
@media (min-width:820px){.result{border-top:0;border-left:1px solid var(--line)}}
.result:focus{outline:none}
.r-label{margin:0;color:var(--accent-ink);font-weight:600;font-size:.92rem}
.r-big{margin:.15rem 0 .8rem;font-family:var(--serif);font-size:clamp(1.8rem,5vw,2.4rem);font-weight:700;line-height:1.15;font-variant-numeric:tabular-nums;word-break:break-word}
.r-rows{margin:0;display:grid;gap:.1rem}
.r-rows div{display:flex;justify-content:space-between;gap:1rem;padding:.4rem 0;border-bottom:1px solid rgba(15,92,85,.15)}
.r-rows dt{color:var(--muted)}
.r-rows dd{margin:0;font-weight:600;font-variant-numeric:tabular-nums;text-align:right}
.r-note{font-size:.85rem;color:var(--muted);margin:.8rem 0 0}
.r-error{color:var(--warn);font-weight:600;margin:0}
.course{display:grid;grid-template-columns:1fr 1fr;gap:.6rem;padding:.8rem 0;border-bottom:1px dashed var(--line);align-items:end}
@media (min-width:620px){.course{grid-template-columns:2fr 1fr 1fr 1.2fr auto}}
.course .remove{font:inherit;font-size:.85rem;background:none;border:1px solid var(--line);border-radius:8px;min-height:44px;padding:0 .8rem;cursor:pointer;color:var(--muted)}

/* schedule */
details.sched-box{margin-top:1rem;background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:.2rem 1rem}
details.sched-box summary{cursor:pointer;font-weight:600;padding:.7rem 0;min-height:44px}
.table-scroll{overflow-x:auto;max-height:28rem;overflow-y:auto;margin-bottom:1rem}
table{border-collapse:collapse;width:100%;font-size:.92rem;font-variant-numeric:tabular-nums}
th,td{padding:.45rem .6rem;text-align:right;border-bottom:1px solid var(--line);white-space:nowrap}
th:first-child,td:first-child{text-align:left}
thead th{position:sticky;top:0;background:#faf8f3;font-weight:600}
.prose table{margin:1rem 0;background:var(--card)}

/* content blocks */
.formula{background:var(--card);border:1px solid var(--line);border-left:4px solid var(--accent);border-radius:8px;padding:.9rem 1.1rem;font-family:ui-monospace,"Cascadia Mono",Consolas,monospace;font-size:.95rem;overflow-x:auto;white-space:pre-wrap}
.example{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:1rem 1.2rem}
.example ol{padding-left:1.2rem;margin:.4rem 0}
.notice{background:var(--warn-soft);border:1px solid #efd9c4;border-radius:8px;padding:.8rem 1rem;font-size:.92rem;color:#5a2a0d;margin:1.2rem 0}
.faq details{border-bottom:1px solid var(--line);padding:.2rem 0}
.faq summary{cursor:pointer;font-weight:600;padding:.75rem 0;list-style-position:outside}
.faq details p{margin:.1rem 0 .9rem}
.sources li{margin:.35rem 0}
.meta{font-size:.88rem;color:var(--muted)}
.related{display:flex;flex-wrap:wrap;gap:.5rem;padding:0;list-style:none}
.related a{display:inline-block;padding:.45rem .8rem;border:1px solid var(--line);border-radius:999px;background:var(--card);text-decoration:none;color:var(--ink);font-size:.92rem}
.related a:hover{border-color:var(--accent);color:var(--accent)}

/* home */
.hero{padding:1.6rem 0 .6rem}
.hero h1{max-width:20ch}
.group{margin-top:2rem}
.group h2{font-size:1.1rem;font-family:var(--sans);text-transform:uppercase;letter-spacing:.08em;color:var(--muted);margin:0 0 .7rem;padding:0}
.cards{display:grid;gap:.8rem;grid-template-columns:repeat(auto-fill,minmax(250px,1fr));padding:0;margin:0;list-style:none}
.cards a{display:block;height:100%;background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:1rem 1.1rem;text-decoration:none;color:var(--ink);transition:border-color .15s,transform .15s}
.cards a:hover{border-color:var(--accent);transform:translateY(-1px)}
.cards strong{display:block;font-family:var(--serif);font-size:1.1rem;margin-bottom:.2rem}
.cards span{color:var(--muted);font-size:.93rem}
@media (prefers-reduced-motion:reduce){.cards a{transition:none}.cards a:hover{transform:none}}

/* footer */
.site-foot{border-top:1px solid var(--line);padding:1.6rem 0 2.2rem;font-size:.9rem;color:var(--muted)}
.site-foot .wrap{display:flex;flex-wrap:wrap;justify-content:space-between;gap:1rem}
.site-foot nav a{color:var(--muted);margin-right:1rem}
.site-foot p{margin:0}

/* header shared with renewpage.com */
.site-head .wrap{flex-wrap:wrap;row-gap:.2rem;padding-top:.4rem;padding-bottom:.4rem}
.logo{display:flex;align-items:center;gap:9px;font-family:var(--serif);font-weight:700;font-size:1.2rem;color:var(--ink);text-decoration:none;letter-spacing:-.01em}
.logo i{width:28px;height:28px;border-radius:8px;display:grid;place-items:center;font-style:normal;font-size:15px;color:#0f1222;
  background:conic-gradient(from 200deg,#ff6b4a,#ffc35c,#2ec5b6,#ff6b4a)}
.topnav{display:flex;flex-wrap:wrap;gap:.2rem 1.1rem;margin-left:auto;margin-right:1rem}
.topnav a{color:var(--muted);text-decoration:none;font-size:.95rem;padding:.35rem 0;min-height:44px;display:inline-flex;align-items:center}
.topnav a:hover{color:var(--ink)}
.topnav a[aria-current]{color:var(--accent);font-weight:600}
.lang select{font:inherit;font-size:.9rem;padding:.35rem .5rem;border:1px solid var(--line);border-radius:8px;background:#fff;color:var(--ink);min-height:40px}
.sr{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap}
@media (max-width:640px){.topnav{order:3;width:100%;margin:0;justify-content:flex-start}.lang{margin-left:auto}}
:lang(ja) h1,:lang(ja) h2,:lang(zh-Hant) h1,:lang(zh-Hant) h2,:lang(ko) h1,:lang(ko) h2{font-family:var(--sans);letter-spacing:0}
:lang(ja) body,:lang(zh-Hant) body,:lang(ko) body{word-break:keep-all;overflow-wrap:anywhere}