/* My Gravel Calculator — hand-written stylesheet, no framework, no external fonts. */

*, *::before, *::after { box-sizing: border-box; }

:root {
  --ink: #1b1916;
  --ink-soft: #3b3730;
  --muted: #6d675c;
  --paper: #faf7f2;
  --surface: #ffffff;
  --stone: #e4ddd1;
  --stone-deep: #cfc5b4;
  --rust: #a8481a;
  --rust-deep: #8a3a13;
  --moss: #2c6151;
  --amber: #e2a54a;
  --radius: 14px;
  --shadow: 0 1px 2px rgba(27, 25, 22, .05), 0 12px 32px -18px rgba(27, 25, 22, .35);
  --sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --serif: "Iowan Old Style", "Palatino Linotype", Palatino, "Book Antiqua", Georgia, serif;
  --mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace;
}

html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--paper);
  background-image:
    radial-gradient(circle at 12% 8%, rgba(226, 165, 74, .10), transparent 42%),
    radial-gradient(circle at 88% 0%, rgba(44, 97, 81, .08), transparent 38%);
  background-repeat: no-repeat;
  color: var(--ink);
  font-family: var(--sans);
  font-size: 17px;
  line-height: 1.65;
}

.wrap { width: min(1080px, 100% - 2.5rem); margin-inline: auto; }
.narrow { width: min(760px, 100% - 2.5rem); margin-inline: auto; }

a { color: var(--rust-deep); text-underline-offset: 3px; }
a:hover { color: var(--rust); }

/* ---------- header ---------- */

.site-head {
  border-bottom: 1px solid var(--stone);
  background: rgba(250, 247, 242, .92);
  backdrop-filter: saturate(160%) blur(8px);
  position: sticky; top: 0; z-index: 20;
}
.site-head .bar {
  display: flex; align-items: center; gap: 1.25rem;
  padding: .85rem 0; flex-wrap: wrap;
}
.wordmark {
  display: inline-flex; align-items: center; gap: .55rem;
  font-family: var(--serif); font-size: 1.12rem; font-weight: 600;
  letter-spacing: -.01em; color: var(--ink); text-decoration: none;
}
.wordmark svg { display: block; }
.wordmark b { color: var(--rust-deep); font-weight: 600; }
.site-nav { margin-left: auto; display: flex; gap: 1.4rem; flex-wrap: wrap; }
.site-nav a {
  color: var(--ink-soft); text-decoration: none; font-size: .93rem;
  padding-bottom: 2px; border-bottom: 2px solid transparent;
}
.site-nav a:hover { color: var(--rust-deep); border-bottom-color: var(--amber); }
.site-nav a[aria-current="page"] { color: var(--rust-deep); border-bottom-color: var(--rust); }

/* ---------- hero ---------- */

.hero { padding: 3rem 0 1.75rem; }
.eyebrow {
  font-size: .74rem; letter-spacing: .16em; text-transform: uppercase;
  color: var(--moss); font-weight: 700; margin: 0 0 .75rem;
}
h1 {
  font-family: var(--serif); font-weight: 600; letter-spacing: -.02em;
  font-size: clamp(2.05rem, 5.2vw, 3.05rem); line-height: 1.12;
  margin: 0 0 .9rem; max-width: 20ch;
}
.lede { font-size: 1.12rem; color: var(--ink-soft); max-width: 62ch; margin: 0 0 1rem; }

/* ---------- calculator ---------- */

.calc {
  display: grid; grid-template-columns: 1.15fr .85fr; gap: 0;
  background: var(--surface); border: 1px solid var(--stone);
  border-radius: var(--radius); box-shadow: var(--shadow);
  margin-bottom: 2.5rem;
}
/* No overflow:hidden here — it would turn .calc into a scroll container and
   kill position:sticky on the results panel. Corners are rounded per child. */
.calc-inputs { padding: 1.6rem 1.75rem 1.9rem; border-radius: var(--radius) 0 0 var(--radius); }
.calc-out {
  padding: 1.6rem 1.6rem 1.9rem; color: #f3efe8;
  background: linear-gradient(168deg, #2a2621 0%, #1b1916 62%, #211d18 100%);
  position: relative; border-radius: 0 var(--radius) var(--radius) 0;
  clip-path: inset(0 round 0 var(--radius) var(--radius) 0);
}
.calc-out::after {
  content: ""; position: absolute; inset: 0; pointer-events: none; opacity: .5;
  background:
    radial-gradient(circle at 78% 14%, rgba(226, 165, 74, .16), transparent 46%),
    radial-gradient(circle at 22% 96%, rgba(44, 97, 81, .22), transparent 52%);
}
.calc-out > * { position: relative; z-index: 1; }
.calc-out-inner { position: sticky; top: 4.9rem; }

fieldset { border: 0; margin: 0 0 1.35rem; padding: 0; }
legend {
  font-size: .74rem; letter-spacing: .13em; text-transform: uppercase;
  font-weight: 700; color: var(--moss); padding: 0; margin-bottom: .6rem;
}
label { display: block; font-size: .84rem; font-weight: 600; color: var(--ink-soft); margin-bottom: .3rem; }
.hint { font-size: .8rem; color: var(--muted); margin: .35rem 0 0; line-height: 1.5; }

input[type="number"], input[type="text"], select {
  width: 100%; font: inherit; font-size: .97rem; color: var(--ink);
  padding: .55rem .65rem; background: #fff;
  border: 1px solid var(--stone-deep); border-radius: 9px;
  appearance: none; -webkit-appearance: none;
}
select {
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 12 8'%3E%3Cpath fill='%236d675c' d='M1 1.5 6 6.5l5-5'/%3E%3C/svg%3E");
  background-repeat: no-repeat; background-position: right .7rem center;
  background-size: 11px; padding-right: 2rem;
}
input:focus, select:focus, button:focus-visible {
  outline: 2px solid var(--amber); outline-offset: 1px; border-color: var(--rust);
}
input[type="number"]::-webkit-outer-spin-button,
input[type="number"]::-webkit-inner-spin-button { -webkit-appearance: none; margin: 0; }
input[type="number"] { -moz-appearance: textfield; }

.pair { display: grid; grid-template-columns: 1fr 6.4rem; gap: .5rem; }
.row { display: grid; gap: .9rem; }
.row.two { grid-template-columns: 1fr 1fr; }
.field { min-width: 0; }

.shape-switch { display: flex; gap: .5rem; margin-bottom: 1rem; }
.shape-switch input { position: absolute; opacity: 0; pointer-events: none; }
.shape-switch label {
  flex: 1; margin: 0; text-align: center; cursor: pointer;
  padding: .5rem .4rem; border: 1px solid var(--stone-deep); border-radius: 9px;
  font-size: .9rem; color: var(--ink-soft); background: #fdfbf8; transition: .15s;
}
.shape-switch input:checked + label {
  background: var(--ink); color: #fdfbf8; border-color: var(--ink);
}
.shape-switch input:focus-visible + label { outline: 2px solid var(--amber); outline-offset: 1px; }

.areas { display: grid; gap: .9rem; }
.area-block {
  border: 1px dashed var(--stone-deep); border-radius: 11px;
  padding: .95rem 1rem 1.05rem; background: #fdfbf8;
}
.area-block header {
  display: flex; align-items: center; justify-content: space-between;
  margin-bottom: .7rem;
}
.area-block h3 {
  margin: 0; font-size: .8rem; letter-spacing: .1em; text-transform: uppercase;
  color: var(--muted); font-weight: 700; font-family: var(--sans);
}
.btn-mini {
  font: inherit; font-size: .8rem; cursor: pointer; background: none;
  border: 1px solid var(--stone-deep); color: var(--muted);
  border-radius: 7px; padding: .12rem .5rem; line-height: 1.5;
}
.btn-mini:hover { border-color: var(--rust); color: var(--rust-deep); }

.btn-add {
  margin-top: .9rem; font: inherit; font-size: .88rem; cursor: pointer;
  background: #fdfbf8; border: 1px solid var(--stone-deep); border-radius: 9px;
  padding: .5rem .9rem; color: var(--ink-soft); width: 100%;
}
.btn-add:hover { border-color: var(--rust); color: var(--rust-deep); }

/* results */

.result-label {
  font-size: .72rem; letter-spacing: .15em; text-transform: uppercase;
  color: var(--amber); font-weight: 700; margin: 0 0 .3rem;
}
.result-primary {
  font-family: var(--serif); font-size: clamp(2.6rem, 7vw, 3.5rem);
  line-height: 1; letter-spacing: -.03em; margin: 0; color: #fff;
  font-variant-numeric: tabular-nums;
}
.result-primary small { font-size: .3em; letter-spacing: .06em; color: #b9b1a4; display: block; margin-top: .5rem; font-family: var(--sans); text-transform: uppercase; }
.result-order {
  margin: .85rem 0 1.25rem; padding: .55rem .7rem; border-radius: 9px;
  background: rgba(226, 165, 74, .13); border: 1px solid rgba(226, 165, 74, .28);
  font-size: .86rem; color: #f0e5d2;
}
.result-order b { color: #fff; }

.result-grid { display: grid; grid-template-columns: 1fr 1fr; gap: .1rem 1.1rem; }
.result-grid div {
  padding: .55rem 0; border-top: 1px solid rgba(243, 239, 232, .13);
  display: flex; justify-content: space-between; align-items: baseline; gap: .6rem;
}
.result-grid dt, .result-grid .k { font-size: .84rem; color: #b9b1a4; }
.result-grid .v { font-size: 1rem; font-weight: 600; color: #fff; font-variant-numeric: tabular-nums; }

.result-note { font-size: .78rem; color: #a49c8e; margin: 1.15rem 0 0; line-height: 1.55; }
.result-err {
  margin: .9rem 0 0; font-size: .86rem; color: #ffcf9a;
  background: rgba(168, 72, 26, .28); border: 1px solid rgba(226, 165, 74, .35);
  border-radius: 9px; padding: .5rem .7rem;
}
.result-err:empty { display: none; }

/* ---------- prose ---------- */

.prose { padding-bottom: 1rem; }
.prose h2 {
  font-family: var(--serif); font-weight: 600; letter-spacing: -.015em;
  font-size: clamp(1.5rem, 3.4vw, 1.95rem); line-height: 1.2;
  margin: 2.9rem 0 .8rem;
}
.prose h3 {
  font-family: var(--serif); font-weight: 600; font-size: 1.16rem;
  margin: 1.9rem 0 .5rem; letter-spacing: -.01em;
}
.prose p { margin: 0 0 1rem; max-width: 68ch; }
.prose ul, .prose ol { max-width: 66ch; padding-left: 1.15rem; margin: 0 0 1.1rem; }
.prose li { margin-bottom: .45rem; }
.prose strong { color: var(--ink); }

.callout {
  border-left: 3px solid var(--amber); background: #fff9ef;
  padding: 1rem 1.15rem; border-radius: 0 11px 11px 0; margin: 1.5rem 0;
}
.callout p:last-child { margin-bottom: 0; }
.callout p:first-child { margin-top: 0; }

table.data {
  width: 100%; border-collapse: collapse; margin: 1.2rem 0 1.6rem;
  font-size: .93rem; background: var(--surface);
  border: 1px solid var(--stone); border-radius: var(--radius); overflow: hidden;
}
table.data caption {
  caption-side: top; text-align: left; font-size: .84rem; color: var(--muted);
  padding-bottom: .5rem;
}
table.data th, table.data td { padding: .6rem .8rem; text-align: left; border-bottom: 1px solid var(--stone); }
table.data thead th { background: #f4efe6; font-size: .78rem; letter-spacing: .07em; text-transform: uppercase; color: var(--ink-soft); }
table.data tbody tr:last-child td { border-bottom: 0; }
table.data td:not(:first-child), table.data th:not(:first-child) { font-variant-numeric: tabular-nums; }
.table-scroll { overflow-x: auto; -webkit-overflow-scrolling: touch; }

details.faq {
  border-bottom: 1px solid var(--stone); padding: .25rem 0;
}
details.faq summary {
  cursor: pointer; padding: .85rem 0; font-weight: 600; font-size: 1.02rem;
  list-style: none; display: flex; gap: .8rem; align-items: baseline;
}
details.faq summary::-webkit-details-marker { display: none; }
details.faq summary::before {
  content: "+"; color: var(--rust); font-weight: 700; font-size: 1.1rem; flex: none;
}
details.faq[open] summary::before { content: "\2013"; }
details.faq[open] summary { color: var(--rust-deep); }
details.faq .faq-body { padding: 0 0 .9rem 1.6rem; }
details.faq .faq-body p:last-child { margin-bottom: 0; }

/* card links */

.cards { display: grid; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); gap: 1rem; margin: 1.4rem 0 2rem; }
.card {
  display: block; text-decoration: none; color: inherit; background: var(--surface);
  border: 1px solid var(--stone); border-radius: var(--radius); padding: 1.15rem 1.25rem;
  transition: .16s;
}
.card:hover { border-color: var(--rust); transform: translateY(-2px); box-shadow: var(--shadow); }
.card h3 { font-family: var(--serif); margin: 0 0 .35rem; font-size: 1.1rem; color: var(--rust-deep); }
.card p { margin: 0; font-size: .9rem; color: var(--muted); line-height: 1.5; }

/* ---------- footer ---------- */

.site-foot {
  margin-top: 3.5rem; border-top: 1px solid var(--stone);
  background: #f4efe6; padding: 2rem 0 2.5rem; font-size: .88rem; color: var(--muted);
}
.foot-grid { display: flex; flex-wrap: wrap; gap: 1.5rem 2.5rem; justify-content: space-between; }
.site-foot h2 { font-size: .74rem; letter-spacing: .13em; text-transform: uppercase; margin: 0 0 .5rem; color: var(--ink-soft); font-family: var(--sans); }
.site-foot ul { list-style: none; margin: 0; padding: 0; }
.site-foot li { margin-bottom: .3rem; }
.site-foot a { color: var(--ink-soft); text-decoration: none; }
.site-foot a:hover { color: var(--rust-deep); text-decoration: underline; }
.foot-legal { margin-top: 1.75rem; padding-top: 1.25rem; border-top: 1px solid var(--stone-deep); max-width: 70ch; font-size: .82rem; line-height: 1.6; }

.skip {
  position: absolute; left: -9999px; top: 0; background: var(--ink); color: #fff;
  padding: .6rem 1rem; z-index: 40; border-radius: 0 0 8px 0;
}
.skip:focus { left: 0; }

/* ---------- error page ---------- */

.oops { padding: 5rem 0 3rem; text-align: center; }
.oops .code { font-family: var(--serif); font-size: 5rem; line-height: 1; color: var(--stone-deep); margin: 0; }

/* ---------- responsive ---------- */

@media (max-width: 860px) {
  .calc { grid-template-columns: 1fr; }
  .calc-inputs { border-radius: var(--radius) var(--radius) 0 0; }
  .calc-out {
    border-top: 1px solid var(--stone);
    border-radius: 0 0 var(--radius) var(--radius);
    clip-path: inset(0 round 0 0 var(--radius) var(--radius));
  }
  .calc-out-inner { position: static; }
}
@media (max-width: 560px) {
  body { font-size: 16px; }
  .wrap, .narrow { width: calc(100% - 1.75rem); }
  .hero { padding: 2.25rem 0 1.25rem; }
  .calc-inputs, .calc-out { padding: 1.25rem 1.15rem 1.5rem; }
  .row.two { grid-template-columns: 1fr; }
  .result-grid { grid-template-columns: 1fr; }
  .site-nav { gap: 1rem; width: 100%; }
}

@media print {
  .site-head, .site-foot, .btn-add, .btn-mini { display: none; }
  .calc { break-inside: avoid; }
  .calc-out { background: #fff; color: #000; }
  .result-primary, .result-grid .v { color: #000; }
}