/* EverydayCalcs — clean light theme, system fonts, no frameworks */
:root{--bg:#f7f8fa;--surface:#ffffff;--border:#dfe3ea;--text:#1c2430;--muted:#5b6572;
--accent:#0b6bcb;--accent2:#095aa9;--good:#0a7d4f;--radius:12px}
*{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth}
body{background:var(--bg);color:var(--text);font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Helvetica,Arial,sans-serif;line-height:1.65;font-size:17px}
a{color:var(--accent);text-decoration:none}
a:hover{text-decoration:underline}
.wrap{max-width:980px;margin:0 auto;padding:0 20px}
.site-header{background:var(--surface);border-bottom:1px solid var(--border);position:sticky;top:0;z-index:50}
.site-header .wrap{display:flex;align-items:center;justify-content:space-between;padding-top:13px;padding-bottom:13px;flex-wrap:wrap;gap:8px}
.brand{font-weight:800;font-size:1.2rem;color:var(--text)}
.brand span{color:var(--accent)}
.nav a{color:var(--muted);margin-left:20px;font-size:.95rem}
.nav a:hover{color:var(--accent)}
.hero{text-align:center;padding:52px 20px 34px}
.hero h1{font-size:clamp(1.9rem,5vw,2.9rem);line-height:1.15}
.hero h1 span{color:var(--accent)}
.hero p{color:var(--muted);max-width:640px;margin:14px auto 0;font-size:1.05rem}
.grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(280px,1fr));gap:18px;margin:26px 0 10px}
.card{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);padding:20px;transition:transform .15s ease,border-color .15s ease}
.card:hover{transform:translateY(-3px);border-color:var(--accent)}
.card h3{font-size:1.12rem;margin-bottom:6px}
.card h3 a{color:var(--text)}
.card p{color:var(--muted);font-size:.94rem}
main{padding:30px 0 10px}
main h1{font-size:clamp(1.7rem,4.5vw,2.4rem);line-height:1.2;margin-bottom:8px}
.lede{color:var(--muted);font-size:1.05rem;margin-bottom:22px;max-width:720px}
.tool{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);padding:24px;margin-bottom:28px}
.tool label{display:block;font-weight:600;font-size:.95rem;margin:12px 0 5px}
.tool input,.tool select{width:100%;padding:11px 12px;border:1px solid var(--border);border-radius:8px;font-size:1rem;background:#fff;color:var(--text)}
.tool .row{display:grid;grid-template-columns:1fr 1fr;gap:16px}
@media(max-width:640px){.tool .row{grid-template-columns:1fr}}
.btn{display:inline-block;background:var(--accent);color:#fff;font-weight:700;padding:12px 30px;border-radius:999px;font-size:1rem;border:none;cursor:pointer;margin-top:18px}
.btn:hover{background:var(--accent2)}
.result{margin-top:20px;background:#eef6ee;border:1px solid #bfe3c8;border-radius:10px;padding:16px 18px;display:none}
.result.show{display:block}
.result .big{font-size:1.5rem;font-weight:800;color:var(--good)}
.result p{margin:3px 0}
section.copy{max-width:760px}
section.copy h2{font-size:1.45rem;margin:30px 0 10px}
section.copy p{margin-bottom:12px}
section.copy ul{margin:0 0 12px 22px}
section.copy li{margin-bottom:5px}
.formula{background:#eef3fb;border:1px solid #c9dcf5;border-radius:10px;padding:14px 18px;font-family:ui-monospace,Menlo,Consolas,monospace;font-size:.98rem;margin:12px 0;overflow-x:auto}
table.data{width:100%;border-collapse:collapse;margin:14px 0;background:var(--surface);font-size:.95rem}
table.data th,table.data td{border:1px solid var(--border);padding:7px 10px;text-align:left}
table.data th{background:#eef3fb}
.tablewrap{overflow-x:auto}
.faq h2{font-size:1.45rem;margin:30px 0 12px}
.faq .qa{background:var(--surface);border:1px solid var(--border);border-radius:10px;padding:16px 18px;margin-bottom:12px;max-width:760px}
.faq .qa h3{font-size:1.05rem;margin-bottom:5px}
.faq .qa p{color:#38414e}
.related{margin:34px 0 8px}
.related h2{font-size:1.3rem;margin-bottom:12px}
footer{background:var(--surface);border-top:1px solid var(--border);margin-top:44px;padding:26px 0 30px;color:var(--muted);font-size:.94rem}
footer nav{margin-bottom:8px}
footer nav a{margin-right:18px;color:var(--muted)}
footer nav a:hover{color:var(--accent)}
.note{font-size:.9rem;color:var(--muted)}