/* SurfSizer design system */

:root {
  --ocean-900: #06243a;
  --ocean-800: #0a3352;
  --ocean-700: #0f4a72;
  --ocean-600: #14639a;
  --ocean-500: #1c86c9;
  --ocean-100: #dbeefb;
  --ocean-50:  #f0f8fe;

  --sand-600: #b8792c;
  --sand-500: #e09b3d;
  --sand-100: #fdf1de;

  --ink:       #10202c;
  --ink-soft:  #40566a;
  /* Dark enough to clear 4.5:1 on the tinted result panel and the footer,
     which are the lightest surfaces this token ever sits on. */
  --ink-faint: #55697c;

  --paper:     #ffffff;
  --paper-alt: #f5f9fc;
  --line:      #dbe6ee;
  /* Form controls are UI components, so their edges need 3:1 (WCAG 1.4.11).
     --line is far too faint for that; it stays for decorative dividers only. */
  --field-border: #75899a;

  --ok: #17794a;

  /* Accent text sits on the tinted result panel, so it has to flip with theme. */
  --accent-text: var(--ocean-700);
  --accent-label: var(--ocean-600);
  /* Links need the same treatment — the mid-blue is only legible on light. */
  --link: var(--ocean-600);
  --link-hover: var(--ocean-700);

  --radius: 14px;
  --radius-sm: 9px;
  --shadow-sm: 0 1px 2px rgba(10, 40, 62, .07), 0 2px 8px rgba(10, 40, 62, .05);
  --shadow-md: 0 4px 12px rgba(10, 40, 62, .09), 0 12px 32px rgba(10, 40, 62, .07);

  --measure: 68ch;
  --wrap: 1120px;

  --sans: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

@media (prefers-color-scheme: dark) {
  :root {
    --ocean-100: #163d59;
    --ocean-50:  #0e2c42;
    --sand-100:  #3a2a12;
    --ink:       #e6eef5;
    --ink-soft:  #a8bccd;
    --ink-faint: #7e94a7;
    --paper:     #071a29;
    --paper-alt: #0c2337;
    --line:      #1b3d57;
    --field-border: #4d6b85;
    --ok: #4cc98a;
    --accent-text:  #8ecbf2;
    --accent-label: #6fb8e6;
    --link:         #6fb8e6;
    --link-hover:   #a3d5f5;
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, .4);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, .45), 0 12px 32px rgba(0, 0, 0, .35);
  }
}

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

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

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation-duration: .01ms !important; transition-duration: .01ms !important; }
}

body {
  margin: 0;
  font-family: var(--sans);
  font-size: 17px;
  line-height: 1.65;
  color: var(--ink);
  background: var(--paper);
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3, h4 { line-height: 1.2; color: var(--ink); margin: 0 0 .5em; font-weight: 700; letter-spacing: -.015em; }
h1 { font-size: clamp(2rem, 5vw, 3rem); letter-spacing: -.03em; }
h2 { font-size: clamp(1.5rem, 3.2vw, 2rem); margin-top: 2.4em; }
h3 { font-size: 1.17rem; margin-top: 1.8em; }
p, ul, ol { margin: 0 0 1.15em; }
a { color: var(--link); text-underline-offset: 2px; }
a:hover { color: var(--link-hover); }

.wrap { max-width: var(--wrap); margin-inline: auto; padding-inline: 20px; }

/* Body copy runs the full calculator width. Long measures get a little more
   leading so the eye can still find the next line. */
.prose { max-width: none; }
.prose p, .prose li { line-height: 1.72; }
.prose li { margin-bottom: .4em; }
.prose > section > p, .prose .faq-item p { max-width: 100%; }

/* ---------------------------------------------------------------- header */
.site-header {
  border-bottom: 1px solid var(--line);
  background: var(--paper);
  position: sticky; top: 0; z-index: 20;
}
.site-header .wrap { display: flex; align-items: center; justify-content: space-between; gap: 16px; height: 64px; }
.brand { display: flex; align-items: center; gap: 10px; font-weight: 700; font-size: 1.12rem; color: var(--ink); text-decoration: none; letter-spacing: -.02em; }
.brand img { display: block; width: 34px; height: 34px; border-radius: 50%; flex-shrink: 0; }
.site-nav { display: flex; gap: 22px; font-size: .93rem; font-weight: 500; }
.site-nav a { color: var(--ink-soft); text-decoration: none; }
.site-nav a:hover { color: var(--link); }
.site-nav a[aria-current="page"] { color: var(--link); font-weight: 600; }

/* ---------------------------------------------------------------- hero */
.hero {
  background: var(--ocean-900);
  color: #fff;
  padding: 52px 0 128px;
  position: relative;
  overflow: hidden;
}

/* The hero photo is a real <img> rather than a CSS background so it can carry
   alt text. The scrim over it is what keeps the headline readable. */
.hero-media { position: absolute; inset: 0; z-index: 0; }
.hero-media img { width: 100%; height: 100%; object-fit: cover; object-position: 70% 50%; display: block; }
.hero-media::after {
  content: ""; position: absolute; inset: 0;
  background:
    linear-gradient(100deg, rgba(4, 20, 34, .93) 0%, rgba(4, 20, 34, .84) 38%, rgba(4, 20, 34, .46) 70%, rgba(4, 20, 34, .34) 100%),
    linear-gradient(180deg, rgba(4, 20, 34, .55) 0%, rgba(4, 20, 34, .18) 45%, rgba(4, 20, 34, .5) 100%);
}
.hero > .wrap { position: relative; z-index: 2; }

/* Interior pages carry the same hero photo as the home page; they just sit
   shallower, since no calculator card overlaps the curve below them. */
.hero--interior { padding: 46px 0 64px; }
.hero--interior h1 { max-width: 22ch; }

/* An interior hero that has a calculator card overlapping it needs the same
   deep bottom padding as the home page, or the card covers the lede. */
.hero--calc { padding-bottom: 128px; }

/* #cfe6f7 clears 4.5:1 even against the lightest stop of the hero gradient;
   the previous #a8cbe4 only managed 3.59:1 down there. */
.breadcrumb { font-size: .86rem; margin-bottom: 14px; color: #cfe6f7; }
.breadcrumb a { color: #cfe6f7; text-decoration: underline; }
.breadcrumb a:hover { color: #fff; }
.breadcrumb span { padding: 0 6px; opacity: .65; }

main.wrap > .prose > section:first-child > h2 { margin-top: 1.6em; }
.hero::after {
  content: ""; position: absolute; left: 0; right: 0; bottom: -1px; height: 76px;
  background: var(--paper);
  -webkit-mask: radial-gradient(58% 100% at 50% 100%, #000 99%, transparent 100%);
  mask: radial-gradient(58% 100% at 50% 100%, #000 99%, transparent 100%);
}
.hero h1 { color: #fff; max-width: 17ch; }
.hero .lede { font-size: 1.13rem; color: #cfe6f7; max-width: 60ch; margin-bottom: 0; }
.eyebrow {
  display: inline-block; font-size: .74rem; font-weight: 700; letter-spacing: .1em;
  text-transform: uppercase; color: #8ecbf2; margin-bottom: 14px;
}

/* ---------------------------------------------------------------- calculator */
.calc-shell { margin-top: -96px; position: relative; z-index: 5; }
.calc {
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow-md);
  overflow: hidden;
}
.calc-grid { display: grid; grid-template-columns: 1.25fr .95fr; }
@media (max-width: 900px) { .calc-grid { grid-template-columns: 1fr; } }

.calc-inputs { padding: 28px; }
.calc-inputs h2 { margin: 0 0 4px; font-size: 1.28rem; }
.calc-hint { color: var(--ink-faint); font-size: .89rem; margin-bottom: 22px; }

.field { margin-bottom: 17px; }
.field > label, .field-label {
  display: block; font-weight: 600; font-size: .88rem; margin-bottom: 6px; color: var(--ink);
}
.field-note { font-size: .8rem; color: var(--ink-faint); font-weight: 400; }

input[type="number"], select {
  width: 100%; padding: 10px 12px; font: inherit; font-size: .96rem;
  color: var(--ink); background: var(--paper);
  border: 1px solid var(--field-border); border-radius: var(--radius-sm);
  appearance: none;
}
select {
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='8' viewBox='0 0 12 8'%3E%3Cpath fill='%236f8497' d='M1.4 0 6 4.6 10.6 0 12 1.4 6 7.4 0 1.4z'/%3E%3C/svg%3E");
  background-repeat: no-repeat; background-position: right 12px center; padding-right: 34px;
}
input:focus-visible, select:focus-visible, button:focus-visible, .unit-toggle button:focus-visible {
  outline: 2px solid var(--ocean-500); outline-offset: 2px;
}

.weight-row { display: flex; gap: 8px; }
.weight-row input { flex: 1; }
.unit-toggle { display: inline-flex; border: 1px solid var(--field-border); border-radius: var(--radius-sm); overflow: hidden; flex-shrink: 0; }
.unit-toggle button {
  font: inherit; font-size: .87rem; font-weight: 600; padding: 0 14px;
  background: var(--paper); color: var(--ink-soft); border: 0; cursor: pointer;
}
.unit-toggle button[aria-pressed="true"] { background: var(--ocean-600); color: #fff; }

.field-pair { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; }
@media (max-width: 460px) { .field-pair { grid-template-columns: 1fr; } }

/* ---------------------------------------------------------------- result */
.calc-result {
  padding: 28px; background: var(--ocean-50);
  border-left: 1px solid var(--line);
  display: flex; flex-direction: column;
}
@media (max-width: 900px) { .calc-result { border-left: 0; border-top: 1px solid var(--line); } }

.result-label { font-size: .78rem; font-weight: 700; letter-spacing: .09em; text-transform: uppercase; color: var(--accent-label); }
.result-figure { display: flex; align-items: baseline; gap: 8px; margin: 6px 0 2px; }
.result-figure strong { font-size: clamp(2.8rem, 8vw, 3.9rem); font-weight: 800; letter-spacing: -.045em; line-height: 1; color: var(--accent-text); }
.result-figure span { font-size: 1.4rem; font-weight: 700; color: var(--accent-label); }
.result-range { font-size: .94rem; color: var(--ink-soft); margin-bottom: 18px; }
.result-range b { color: var(--ink); font-weight: 600; }

.working { border-top: 1px solid var(--line); padding-top: 15px; margin-top: auto; }
.working h3 { font-size: .84rem; text-transform: uppercase; letter-spacing: .07em; color: var(--ink-faint); margin: 0 0 9px; }
.working-row { display: flex; justify-content: space-between; gap: 12px; font-size: .87rem; padding: 3px 0; color: var(--ink-soft); }
.working-row b { color: var(--ink); font-weight: 600; font-variant-numeric: tabular-nums; }
.working-row.is-total { border-top: 1px solid var(--line); margin-top: 7px; padding-top: 9px; font-weight: 600; color: var(--ink); }
.working-eq { font-size: .84rem; color: var(--ink-faint); margin: 10px 0 0; font-variant-numeric: tabular-nums; }

.length-tip {
  background: var(--sand-100); border-radius: var(--radius-sm);
  padding: 11px 13px; font-size: .88rem; color: var(--ink-soft); margin-top: 14px;
}
.length-tip b { color: var(--ink); }

/* ---------------------------------------------------------------- tables */
.table-scroll { overflow-x: auto; margin: 0 0 1.3em; -webkit-overflow-scrolling: touch; }
table { border-collapse: collapse; width: 100%; min-width: 420px; font-size: .93rem; }
caption { text-align: left; font-size: .87rem; color: var(--ink-faint); padding-bottom: 8px; }
th, td { text-align: left; padding: 9px 13px; border-bottom: 1px solid var(--line); }
thead th { background: var(--paper-alt); font-size: .82rem; text-transform: uppercase; letter-spacing: .05em; color: var(--ink-soft); white-space: nowrap; }
tbody tr:hover { background: var(--paper-alt); }
td.num, th.num { font-variant-numeric: tabular-nums; white-space: nowrap; }

/* ---------------------------------------------------------------- misc blocks */
main section { scroll-margin-top: 80px; }

.callout {
  background: var(--paper-alt); border: 1px solid var(--line);
  border-left: 3px solid var(--ocean-500);
  border-radius: var(--radius-sm); padding: 15px 18px; margin: 1.6em 0;
}
.callout p:last-child { margin-bottom: 0; }
.callout strong { color: var(--ink); }

.faq-item { border-bottom: 1px solid var(--line); padding: 4px 0 14px; }
.faq-item h3 { margin-top: 1.1em; }
.faq-item p:last-child { margin-bottom: 0; }

.method {
  background: var(--paper-alt); border: 1px solid var(--line);
  border-radius: var(--radius); padding: 22px 24px; margin: 2em 0;
}
.method h2 { margin-top: 0; font-size: 1.2rem; }
.method p:last-child { margin-bottom: 0; }

/* ---------------------------------------------------------------- footer */
/* Text results (a "3/2" or an "L") need far less size than a big number. */
.result-figure strong.is-text { font-size: clamp(2.1rem, 5.5vw, 2.8rem); }
.result-sub { font-size: 1.02rem; font-weight: 600; color: var(--ink); margin: 0 0 4px; }
.result-extras {
  background: var(--paper); border: 1px solid var(--line);
  border-radius: var(--radius-sm); padding: 11px 13px;
  font-size: .89rem; color: var(--ink-soft); margin-bottom: 14px;
}
.result-extras b { color: var(--ink); }

.site-footer {
  margin-top: 72px; border-top: 1px solid var(--line);
  background: var(--paper-alt); padding: 36px 0 30px;
  font-size: .89rem; color: var(--ink-faint);
}
.site-footer a { color: var(--ink-soft); }
.footer-row { display: flex; flex-wrap: wrap; gap: 10px 26px; justify-content: space-between; align-items: center; }

/* Full link list in the footer — the header nav can't hold every page, and on
   mobile it is hidden entirely, so this is the real navigation down there. */
.footer-nav {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 22px 30px; padding-bottom: 26px; margin-bottom: 22px;
  border-bottom: 1px solid var(--line);
}
.footer-nav h2 {
  font-size: .78rem; text-transform: uppercase; letter-spacing: .08em;
  color: var(--ink-soft); margin: 0 0 9px;
}
.footer-nav ul { list-style: none; margin: 0; padding: 0; }
.footer-nav li { margin-bottom: 6px; }
.footer-nav a { color: var(--ink-soft); text-decoration: none; }
.footer-nav a:hover { color: var(--link); text-decoration: underline; }

/* Rather than hide the nav on small screens, let it scroll sideways. */
@media (max-width: 860px) {
  .site-nav {
    gap: 16px; overflow-x: auto; -webkit-overflow-scrolling: touch;
    white-space: nowrap; scrollbar-width: none; margin-left: 12px;
  }
  .site-nav::-webkit-scrollbar { display: none; }
}

.visually-hidden {
  position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px;
  overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; border: 0;
}