/* Sheetwise Engineering - MathSheet website. Plain CSS, no framework.
   Colours: charcoal text, MathSheet blue #1f5fae, MathSheet red #d00000 (used sparingly). */
:root {
  --ink: #1d1f23; --ink2: #4a4f57; --muted: #6b7079; --line: #e3e5e8; --soft: #f5f6f8; --soft2: #eef2f8;
  --blue: #1f5fae; --blue-d: #174a88; --red: #d00000; --radius: 10px;
  --shadow: 0 1px 2px rgba(16,24,40,.06), 0 8px 24px rgba(16,24,40,.08);
  --font: "Segoe UI Variable Text", "Segoe UI", system-ui, -apple-system, "Helvetica Neue", Arial, sans-serif;
}
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
body { margin: 0; font-family: var(--font); color: var(--ink); background: #fff; line-height: 1.6; font-size: 17px; }
img { max-width: 100%; height: auto; }
a { color: var(--blue); text-underline-offset: 2px; }
a:hover { color: var(--blue-d); }
:focus-visible { outline: 3px solid #8fb4e6; outline-offset: 2px; border-radius: 4px; }
.skip { position: absolute; left: -999px; top: 8px; background: #fff; padding: 8px 12px; z-index: 50; }
.skip:focus { left: 8px; }
.wrap { max-width: 1160px; margin: 0 auto; padding: 0 24px; }
.narrow { max-width: 820px; }
h1, h2, h3 { line-height: 1.2; letter-spacing: -0.01em; color: var(--ink); }
h1 { font-size: clamp(34px, 5vw, 56px); font-weight: 650; margin: 0 0 18px; letter-spacing: -0.02em; }
h2 { font-size: clamp(27px, 3.4vw, 38px); font-weight: 650; margin: 0 0 14px; }
h3 { font-size: 21px; font-weight: 600; margin: 0 0 8px; }
p { margin: 0 0 14px; }
.lead { font-size: clamp(18px, 2vw, 21px); color: var(--ink2); max-width: 760px; }
.eyebrow { font-size: 14px; font-weight: 600; letter-spacing: .08em; text-transform: uppercase; color: var(--blue); margin: 0 0 10px; }
.muted { color: var(--muted); }
.small { font-size: 14px; }

/* header */
header.top { position: sticky; top: 0; z-index: 20; background: rgba(255,255,255,.92); backdrop-filter: saturate(180%) blur(10px); border-bottom: 1px solid var(--line); }
header.top .wrap { display: flex; align-items: center; justify-content: space-between; gap: 16px; min-height: 64px; flex-wrap: wrap; }
.brand { display: flex; align-items: center; gap: 10px; text-decoration: none; color: var(--ink); }
.brand .tile { width: 34px; height: 34px; border-radius: 8px; background: var(--blue); color: #fff; font-weight: 700; font-size: 20px; display: grid; place-items: center; position: relative; flex: none; }
.brand .tile::after { content: "+"; position: absolute; right: -3px; top: -9px; color: var(--red); font-size: 19px; font-weight: 800; }
.brand b { display: block; font-size: 18px; line-height: 1.1; }
.brand small { display: block; font-size: 12px; color: var(--muted); line-height: 1.2; }
nav.menu { display: flex; align-items: center; flex-wrap: wrap; gap: 4px 22px; font-size: 15px; }
nav.menu a { color: var(--ink2); text-decoration: none; padding: 6px 0; }
nav.menu a:hover, nav.menu a[aria-current="page"] { color: var(--blue); }
nav.menu a[aria-current="page"] { box-shadow: inset 0 -2px 0 var(--blue); }
nav.menu .btn { padding: 8px 16px; font-size: 15px; }

/* buttons */
.btn { display: inline-flex; align-items: center; justify-content: center; gap: 8px; min-height: 46px; padding: 11px 22px; border-radius: 999px; font-weight: 600; font-size: 16px; text-decoration: none; border: 1.5px solid var(--blue); cursor: pointer; transition: background .15s, color .15s; }
.btn.primary { background: var(--blue); color: #fff; }
.btn.primary:hover { background: var(--blue-d); border-color: var(--blue-d); color: #fff; }
.btn.secondary { background: #fff; color: var(--blue); }
.btn.secondary:hover { background: var(--soft2); }
.btn.soon { background: var(--soft); color: var(--muted); border-color: var(--line); cursor: default; }
.btns { display: flex; flex-wrap: wrap; gap: 12px; margin: 22px 0 10px; }
.note { font-size: 14px; color: var(--muted); }

/* sections */
section { padding: 84px 0; }
section.tight { padding: 56px 0; }
section.soft { background: var(--soft); }
.center { text-align: center; }
.center .lead { margin-left: auto; margin-right: auto; }
.hero { padding: 72px 0 0; text-align: center; }
.hero .lead { margin: 0 auto; }
.hero .btns { justify-content: center; }
.hero .shotwrap { margin: 44px auto 0; max-width: 980px; }

/* screenshots */
.frame { display: block; border: 1px solid #d9dce1; border-radius: var(--radius); background: #fff; box-shadow: var(--shadow); overflow: hidden; }
.frame img { display: block; width: 100%; }
.frame.bar::before { content: ""; display: block; height: 22px; background: #f0f0f0 radial-gradient(circle at 14px 11px, #d0d3d8 4px, transparent 5px) , #f0f0f0; border-bottom: 1px solid #e2e4e8; }
figure { margin: 0; }
figcaption { font-size: 14px; color: var(--muted); margin-top: 10px; }
button.zoom { all: unset; display: block; cursor: zoom-in; width: 100%; }
button.zoom:focus-visible { outline: 3px solid #8fb4e6; outline-offset: 3px; border-radius: var(--radius); }

/* layouts */
.split { display: grid; grid-template-columns: 5fr 7fr; gap: 56px; align-items: center; }
.split.rev { grid-template-columns: 7fr 5fr; }
.split.rev > :first-child { order: 2; }
.grid3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 22px; }
.grid2 { display: grid; grid-template-columns: repeat(2, 1fr); gap: 28px; }
.card { border: 1px solid var(--line); border-radius: var(--radius); padding: 24px; background: #fff; }
.card p { margin: 0; color: var(--ink2); }
.card .ic { width: 38px; height: 38px; border-radius: 9px; background: var(--soft2); color: var(--blue); display: grid; place-items: center; font-weight: 700; margin-bottom: 14px; font-size: 18px; }
ul.ticks { list-style: none; padding: 0; margin: 14px 0; }
ul.ticks li { position: relative; padding-left: 28px; margin: 8px 0; color: var(--ink2); }
ul.ticks li::before { content: ""; position: absolute; left: 2px; top: 8px; width: 12px; height: 7px; border-left: 2.5px solid var(--blue); border-bottom: 2.5px solid var(--blue); transform: rotate(-45deg); }

/* four words strip */
.steps4 { display: grid; grid-template-columns: repeat(4, 1fr); gap: 0; border: 1px solid var(--line); border-radius: var(--radius); overflow: hidden; }
.steps4 div { padding: 22px 22px; border-right: 1px solid var(--line); background: #fff; }
.steps4 div:last-child { border-right: 0; }
.steps4 b { display: block; font-size: 19px; color: var(--blue); }
.steps4 span { color: var(--ink2); font-size: 15px; }

/* tabs (home demo) */
.tabs [role="tablist"] { display: flex; flex-wrap: wrap; justify-content: center; gap: 8px; margin: 26px 0 28px; }
.tabs [role="tab"] { font: inherit; font-size: 15px; font-weight: 600; padding: 9px 18px; border-radius: 999px; border: 1px solid var(--line); background: #fff; color: var(--ink2); cursor: pointer; min-height: 42px; }
.tabs [role="tab"][aria-selected="true"] { background: var(--ink); border-color: var(--ink); color: #fff; }
.tabs [role="tabpanel"] { display: grid; grid-template-columns: 4fr 8fr; gap: 44px; align-items: center; text-align: left; }
.tabs [role="tabpanel"][hidden] { display: none; }
.js .tabs .nojs-title { display: none; }
.tabs [role="tabpanel"] a { display: inline-block; padding: 8px 0; font-weight: 600; }
.tabs .nojs-title { margin-top: 30px; }

/* worked example component */
.worked { border: 1px solid var(--line); border-radius: var(--radius); background: #fff; overflow: hidden; }
.worked > header { padding: 18px 24px; border-bottom: 1px solid var(--line); background: var(--soft); }
.worked > header .eyebrow { margin: 0 0 4px; }
.worked > header h3 { margin: 0; }
.worked .body { display: grid; grid-template-columns: 4fr 7fr; }
.worked .body > div { padding: 22px 24px; }
.worked .body > div + div { border-left: 1px solid var(--line); background: #fcfcfd; }
.worked dl { margin: 0; }
.worked dt { font-size: 13px; font-weight: 700; text-transform: uppercase; letter-spacing: .06em; color: var(--muted); margin-top: 14px; }
.worked dt:first-child { margin-top: 0; }
.worked dd { margin: 4px 0 0; color: var(--ink2); }
details.more { margin-top: 12px; }
details.more summary { cursor: pointer; color: var(--blue); font-weight: 600; }

/* flow (Excel) */
.flow { display: grid; grid-template-columns: 1fr auto 1fr auto 1fr; gap: 16px; align-items: center; }
.flow .arrow { font-size: 28px; color: var(--blue); text-align: center; }
.flow h3 { font-size: 17px; margin: 0 0 8px; }

/* before / after */
.ba { display: grid; grid-template-columns: 5fr 9fr; gap: 24px; align-items: start; }
.tag { display: inline-block; font-size: 12px; font-weight: 700; letter-spacing: .06em; text-transform: uppercase; padding: 3px 10px; border-radius: 999px; margin-bottom: 10px; }
.tag.before { background: #eef0f3; color: var(--ink2); }
.tag.after { background: #e3edf9; color: var(--blue); }

/* feature page sub nav */
.subnav { position: sticky; top: 64px; z-index: 10; background: rgba(255,255,255,.95); border-bottom: 1px solid var(--line); }
.subnav .wrap { display: flex; gap: 6px 22px; overflow-x: auto; white-space: nowrap; padding-top: 10px; padding-bottom: 10px; font-size: 15px; scrollbar-width: thin; }
.subnav a { color: var(--ink2); text-decoration: none; }
.subnav a:hover { color: var(--blue); }
.feature-head { max-width: 820px; margin-bottom: 36px; }

/* pricing */
.pricebox { max-width: 560px; margin: 0 auto; border: 1px solid var(--line); border-radius: 16px; box-shadow: var(--shadow); padding: 36px; background: #fff; text-align: left; }
.pricebox .name { font-weight: 600; color: var(--ink2); }
.pricebox .amount { font-size: 64px; font-weight: 650; letter-spacing: -0.03em; line-height: 1; margin: 10px 0 6px; }
.pricebox .amount small { font-size: 18px; font-weight: 500; color: var(--muted); letter-spacing: 0; }
.compare { width: 100%; border-collapse: collapse; font-size: 16px; }
.compare th, .compare td { text-align: left; padding: 12px 14px; border-bottom: 1px solid var(--line); vertical-align: top; }
.compare th { background: var(--soft); font-weight: 600; }
.tablewrap { overflow-x: auto; border: 1px solid var(--line); border-radius: var(--radius); }
.faq details { border-bottom: 1px solid var(--line); padding: 16px 0; }
.faq summary { cursor: pointer; font-weight: 600; font-size: 18px; list-style-position: outside; }
.faq details p { margin: 10px 0 0; color: var(--ink2); }

/* text pages */
.page { padding: 56px 0 80px; }
.page h1 { font-size: clamp(32px, 4vw, 44px); }
.page h2 { font-size: 24px; margin-top: 36px; }
.updated { color: var(--muted); font-size: 14px; margin-bottom: 26px; }
pre.eula { white-space: pre-wrap; font-family: Consolas, "Courier New", monospace; font-size: 14px; background: var(--soft); border: 1px solid var(--line); border-radius: var(--radius); padding: 22px; overflow-x: auto; }
pre.cmd { white-space: pre-wrap; word-break: break-all; font-family: Consolas, "Courier New", monospace; font-size: 14px; background: var(--soft); border: 1px solid var(--line); border-radius: var(--radius); padding: 12px 16px; }
code.hash { font-family: Consolas, monospace; word-break: break-all; background: var(--soft); padding: 1px 6px; border-radius: 4px; }
.callout { border-left: 4px solid var(--blue); background: var(--soft2); padding: 16px 20px; border-radius: 0 var(--radius) var(--radius) 0; margin: 20px 0; }
.callout p:last-child { margin: 0; }
ol.howto { padding-left: 22px; }
ol.howto li { margin: 10px 0; }
kbd { font-family: Consolas, monospace; font-size: 14px; background: var(--soft); border: 1px solid #cfd3d8; border-bottom-width: 2px; border-radius: 5px; padding: 1px 6px; }

/* CTA band */
.band { background: var(--ink); color: #fff; border-radius: 18px; padding: 54px 40px; text-align: center; }
.band h2 { color: #fff; }
.band .lead { color: #c9ced6; margin-left: auto; margin-right: auto; }
.band .btns { justify-content: center; }
.band .btn.secondary { background: transparent; color: #fff; border-color: #8a929d; }
.band .btn.secondary:hover { background: rgba(255,255,255,.08); }
.band .btn.soon { background: transparent; color: #aab1bb; border-color: #4a515b; }
.band .note { color: #aab1bb; }

/* footer */
footer.bottom { border-top: 1px solid var(--line); background: var(--soft); padding: 44px 0 30px; font-size: 14px; color: var(--muted); margin-top: 0; }
footer.bottom .cols { display: grid; grid-template-columns: 2fr 1fr 1fr 1fr; gap: 28px; }
footer.bottom h4 { margin: 0 0 10px; font-size: 14px; color: var(--ink); }
footer.bottom a { display: block; color: var(--ink2); text-decoration: none; margin: 6px 0; }
footer.bottom a:hover { color: var(--blue); }
footer.bottom .legal { margin-top: 30px; padding-top: 18px; border-top: 1px solid var(--line); }

/* lightbox */
dialog.lightbox { border: 0; padding: 0; background: transparent; max-width: 96vw; max-height: 94vh; }
dialog.lightbox::backdrop { background: rgba(10,12,16,.82); }
dialog.lightbox img { display: block; max-width: 96vw; max-height: 88vh; width: auto; border-radius: 6px; background: #fff; }
dialog.lightbox .cap { color: #e6e8eb; font-size: 14px; margin-top: 8px; text-align: center; }
dialog.lightbox .x { position: fixed; top: 14px; right: 18px; font: 600 15px var(--font); color: #fff; background: rgba(255,255,255,.14); border: 0; border-radius: 999px; padding: 10px 16px; cursor: pointer; }

/* coming soon: strip under the header + launch news sign-up */
.soonbar { background: var(--soft2); border-bottom: 1px solid var(--line); font-size: 15px; }
.soonbar .wrap { padding-top: 9px; padding-bottom: 9px; }
.soonbar b { color: var(--red); }
.soonbar a { display: inline-block; padding: 4px 0; font-weight: 600; }
.newsbox { border: 2px solid var(--blue); border-radius: 14px; padding: 30px 32px; background: #fff; box-shadow: var(--shadow); }
.newsbox h2 { margin: 0 0 8px; }
.newsbox > p { margin: 0 0 18px; color: var(--ink2); }
.signup .fields { display: grid; grid-template-columns: 2fr 1.3fr auto; gap: 14px; align-items: end; }
.signup label { display: block; font-size: 14px; font-weight: 600; margin-bottom: 6px; }
.signup input { width: 100%; box-sizing: border-box; min-height: 46px; padding: 0 14px; font: inherit; font-size: 16px; border: 1px solid #c3c8cf; border-radius: 8px; }
.signup input:focus { outline: 3px solid #8fb4e6; outline-offset: 1px; border-color: var(--blue); }
.signup .btn { font: inherit; font-weight: 600; cursor: pointer; }
.signup .note { margin: 12px 0 0; }
[hidden] { display: none !important; }

/* responsive */
@media (max-width: 960px) {
  .split, .split.rev, .tabs [role="tabpanel"], .worked .body, .ba, .grid2 { grid-template-columns: 1fr; gap: 28px; }
  .split.rev > :first-child { order: 0; }
  .worked .body > div + div { border-left: 0; border-top: 1px solid var(--line); }
  .grid3 { grid-template-columns: 1fr 1fr; }
  .steps4 { grid-template-columns: 1fr 1fr; }
  .steps4 div:nth-child(2) { border-right: 0; }
  .steps4 div:nth-child(-n+2) { border-bottom: 1px solid var(--line); }
  .flow { grid-template-columns: 1fr; }
  .flow .arrow { transform: rotate(90deg); }
  footer.bottom .cols { grid-template-columns: 1fr 1fr; }
  section { padding: 60px 0; }
}
@media (max-width: 600px) {
  body { font-size: 16px; }
  .wrap { padding: 0 18px; }
  .grid3, .steps4 { grid-template-columns: 1fr; }
  .steps4 div { border-right: 0; border-bottom: 1px solid var(--line); }
  .steps4 div:last-child { border-bottom: 0; }
  header.top .wrap { padding-top: 8px; padding-bottom: 8px; }
  nav.menu { gap: 2px 16px; font-size: 15px; width: 100%; }
  .subnav { top: 0; position: static; }
  .pricebox { padding: 26px 22px; }
  .band { padding: 40px 22px; border-radius: 14px; }
  footer.bottom .cols { grid-template-columns: 1fr; }
  .hero { padding-top: 44px; }
  .signup .fields { grid-template-columns: 1fr; }
  .newsbox { padding: 24px 20px; }
}
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } }
@media print { header.top, .subnav, footer.bottom, .btns { display: none; } }
/* demo clips (home page #demos) */
.clips { display: grid; grid-template-columns: repeat(3, 1fr); gap: 22px; margin-top: 28px; }
.clips figure { margin: 0; }
.clips video { display: block; width: 100%; height: auto; border: 1px solid var(--line); border-radius: var(--radius); background: #fff; }
.clips figcaption { margin-top: 8px; font-size: .95rem; color: var(--ink2); }
@media (max-width: 960px) { .clips { grid-template-columns: 1fr 1fr; } }
@media (max-width: 600px) { .clips { grid-template-columns: 1fr; } }